JP2014032214A

JP2014032214A - Imaging apparatus and focus position detection method

Info

Publication number: JP2014032214A
Application number: JP2010267932A
Authority: JP
Inventors: Takashi Aoki; 貴嗣青木
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2010-11-30
Filing date: 2010-11-30
Publication date: 2014-02-20
Also published as: WO2012073727A1

Abstract

PROBLEM TO BE SOLVED: To achieve fast and accurate phase difference AF.SOLUTION: Pupil-divided first and second phase difference pixels x and y are formed in arrays within a phase difference detection area 40 of a light receiving surface, and control means is provided which controls a focus lens position in a preceding stage of an imaging element into a focus position on the basis of an amount of phase difference between detection information of the pixels x and y. The control means divides the area 40 into a plurality of divided areas I, II, III, and IV in the rectangular direction to a direction of the phase difference, adds output signals of a plurality of pixels x arranged in a line in the rectangular direction within each divided area to each of a plurality of pixels x arrayed in a phase difference detection direction within the divided area, performs similar addition for pixels y and operates a correlation between a signal resulting from addition for pixels x and a signal resulting from addition for pixels y for each divided area to obtain an evaluation curve, subjects the evaluation curve calculated for each divided area to prescribed operation processing to obtain an evaluation curve for the entire area, and obtains the amount of phase difference from the evaluation curve for the entire area.

Description

本発明は、被写体までの距離を検出し撮影レンズの焦点位置制御を行う撮像装置及びその合焦位置検出方法に関する。 The present invention relates to an imaging apparatus that detects a distance to a subject and controls a focal position of a photographic lens, and an in-focus position detection method thereof.

主要な被写体までの距離を検出する合焦位置検出方法には、コントラスト方式や位相差ＡＦ方式がある。位相差ＡＦ方式は、コントラスト方式に比べて合焦位置の検出を高速，高精度に行うことができるため、一眼レフカメラで多く採用されている。 In-focus position detection methods for detecting the distance to the main subject include a contrast method and a phase difference AF method. The phase difference AF method is often used in single-lens reflex cameras because it can detect the in-focus position at a higher speed and with higher accuracy than the contrast method.

従来の一眼レフカメラで採用されている位相差ＡＦ方式は、例えば下記の特許文献１に記載されている様に、被写体画像を撮像する固体撮像素子とは別に、２つの左右に配置される位相差検出用ラインセンサを設け、第１のラインセンサの検出情報と第２のラインセンサの検出情報との位相差に基づき、主要被写体までの距離を検出する構成になっている。 The phase difference AF method employed in the conventional single-lens reflex camera is, for example, as described in Patent Document 1 below, arranged separately on two right and left sides apart from a solid-state image sensor that captures a subject image. A phase difference detection line sensor is provided, and the distance to the main subject is detected based on the phase difference between the detection information of the first line sensor and the detection information of the second line sensor.

この特許文献１記載の位相差ＡＦ方式は、固体撮像素子とは別に位相差検出用のラインセンサが必要となり、部品コスト，製造コストが嵩んでしまい、更に装置が大型化してしまうという問題がある。 The phase difference AF method described in Patent Document 1 requires a line sensor for phase difference detection in addition to the solid-state imaging device, which increases the parts cost and manufacturing cost, and further increases the size of the apparatus. .

これに対し、下記の特許文献２に記載されている様に、固体撮像素子受光面上に位相差検出用の画素を設けたものが提案されている。被写体画像を撮像する固体撮像素子として位相差検出用の画素が形成された固体撮像素子を採用することで、外部の位相差検出用センサが不要となり、低コスト化を図ることが可能となる。 On the other hand, as described in Patent Document 2 below, a pixel in which a pixel for detecting a phase difference is provided on a light receiving surface of a solid-state imaging device has been proposed. By adopting a solid-state image sensor in which pixels for phase difference detection are formed as a solid-state image sensor that captures a subject image, an external phase difference detection sensor becomes unnecessary, and the cost can be reduced.

特開２０１０―８４４３号公報JP 2010-8443 A 特開２０１０―９１９９１号公報JP 2010-91991 A

しかしながら、特許文献２に記載の従来技術は、一眼レフカメラが対象であり、大面積の固体撮像素子を搭載することが前提となっている。位相差検出画素は、特許文献２に記載されている様に、１対の隣接画素の夫々の遮光膜開口を小さくし、かつ一方と他方で遮光膜開口位置を位相差検出方向（通常の場合は左右方向）にずらすことで位相差を検出する構成になっている。 However, the conventional technique described in Patent Document 2 is intended for single-lens reflex cameras, and is premised on mounting a large-area solid-state imaging device. In the phase difference detection pixel, as described in Patent Document 2, the light shielding film opening of each of a pair of adjacent pixels is made small, and the light shielding film opening position of one and the other is set to the phase difference detection direction (normal case). Is configured to detect the phase difference by shifting in the horizontal direction.

一画素一画素の受光面積を大きくとれる大判（大面積）の固体撮像素子であれば、遮光膜開口を少しくらい小さくしても位相差情報を高速かつ高精度にとることができる。しかし、一画素一画素の受光面積を大きくとれない、例えばコンパクトカメラ等に搭載する固体撮像素子では、もともとの遮光膜開口が小さいため、これを更に小さくし、受光時間を短時間にして位相差情報を高速に取得すると、位相差情報の精度つまり合焦位置検出精度が落ちてしまうという問題が生じる。 With a large-sized (large area) solid-state imaging device capable of increasing the light receiving area of each pixel, phase difference information can be obtained at high speed and with high accuracy even if the light shielding film aperture is slightly reduced. However, the light receiving area of each pixel cannot be increased. For example, in a solid-state image sensor mounted on a compact camera or the like, the original light-shielding film aperture is small. If the information is acquired at high speed, there arises a problem that the accuracy of the phase difference information, that is, the focus position detection accuracy is lowered.

本発明の目的は、小面積の固体撮像素子に適用した場合でも高速かつ高精度に位相差情報を取得し合焦位置を求めることができる撮像装置及びその合焦位置検出方法を提供することにある。 An object of the present invention is to provide an imaging apparatus capable of acquiring phase difference information and obtaining a focus position at high speed and with high accuracy even when applied to a solid-state image sensor having a small area, and a focus position detection method thereof. is there.

本発明の撮像装置及びその合焦位置検出方法は、被写体の画像を撮像する受光面に設けられた位相差検出エリア内に、瞳分割した第１の位相差検出画素及び第２の位相差検出画素で構成されるペア画素が配列形成された撮像素子と、
該撮像素子の前段に置かれ、前記被写体の合焦した光学像を前記受光面に結像させるフォーカスレンズと、
前記第１の位相差検出画素の検出情報と前記第２の位相差検出画素の検出情報との位相差を求め、該位相差に基づき前記フォーカスレンズを前記合焦する位置に制御する制御手段とを備える撮像装置であって、
前記位相差の検知方向に対して直角方向に前記位相差検出エリアを複数の分割エリアに分割し、
前記分割エリア毎に、当該分割エリア内の前記直角方向に一列に並ぶ複数の前記第１の位相差検出画素の出力信号を、該分割エリア内の前記位相差を検出する方向に並ぶ複数の前記第１の位相差検出画素毎に加算すると共に、前記直角方向に一列に並ぶ複数の前記第２の位相差検出画素の出力信号を、該分割エリア内の前記位相差を検出する方向に並ぶ複数の前記第２の位相差検出画素毎に加算し、
前記分割エリア毎に、前記第１の位相差検出画素の前記加算した信号と前記第２の位相差検出画素の前記加算した信号との相関関係を演算して分割エリア毎の相関演算曲線を算出し、
前記分割エリア毎に算出された前記分割エリア毎の相関演算曲線のうち任意複数個の前記相関演算曲線間に所定演算処理を施して複数エリアの相関演算曲線を求め、該複数エリアの相関演算曲線から前記フォーカスレンズを前記合焦位置に制御する位相差を求めることを特徴とする。 According to the imaging apparatus and the focus position detection method of the present invention, a first phase difference detection pixel and a second phase difference detection that are divided into pupils in a phase difference detection area provided on a light receiving surface that captures an image of a subject. An image sensor in which a pair of pixels composed of pixels is formed;
A focus lens that is placed in front of the image sensor and forms a focused optical image of the subject on the light receiving surface;
Control means for obtaining a phase difference between detection information of the first phase difference detection pixel and detection information of the second phase difference detection pixel, and controlling the focus lens to the in-focus position based on the phase difference; An imaging device comprising:
Dividing the phase difference detection area into a plurality of divided areas in a direction perpendicular to the phase difference detection direction;
For each of the divided areas, the output signals of the plurality of first phase difference detection pixels arranged in a line in the perpendicular direction in the divided area are output in the direction in which the phase difference in the divided area is detected. A plurality of first phase difference detection pixels are added and a plurality of second phase difference detection pixel output signals arranged in a line in the perpendicular direction are arranged in a direction in which the phase difference in the divided area is detected. For each of the second phase difference detection pixels,
For each divided area, a correlation calculation curve for each divided area is calculated by calculating a correlation between the added signal of the first phase difference detection pixel and the added signal of the second phase difference detection pixel. And
A correlation calculation curve for a plurality of areas is obtained by performing a predetermined calculation process between the plurality of correlation calculation curves among the correlation calculation curves for each of the divided areas calculated for each of the divided areas. To obtain a phase difference for controlling the focus lens to the in-focus position.

本発明によれば、分割エリア毎に評価曲線（相関演算曲線）を求め、複数の評価曲線に対し所定演算処理を施して全体（複数エリア）の評価曲線を求め、この全体の評価曲線（全エリア評価曲線）から位相差量を算出するため、画素加算数が多くなって被写体のパターンが平均化されてしまうことがなく、小さな固体撮像素子を搭載する場合であっても高速かつ高精度に位相差ＡＦを行うことが可能となる。 According to the present invention, an evaluation curve (correlation calculation curve) is obtained for each divided area, and a predetermined calculation process is performed on the plurality of evaluation curves to obtain an entire (multiple area) evaluation curve. Since the phase difference amount is calculated from the area evaluation curve), the pixel addition number does not increase and the pattern of the subject is not averaged. Even when a small solid-state image sensor is mounted, it is fast and highly accurate. It is possible to perform phase difference AF.

本発明の一実施形態に係る撮像装置の機能ブロック構成図である。It is a functional block block diagram of the imaging device which concerns on one Embodiment of this invention. 図１に示す固体撮像素子の受光面上に設ける位相差検出エリアの説明図である。It is explanatory drawing of the phase difference detection area provided on the light-receiving surface of the solid-state image sensor shown in FIG. 図２の点線矩形枠内の表面拡大模式図である。It is a surface expansion schematic diagram in the dotted-line rectangular frame of FIG. 図３の位相差検出画素とその検出信号だけを抜き出し位相差量の概念を説明する図である。FIG. 4 is a diagram for explaining a concept of a phase difference amount by extracting only the phase difference detection pixel of FIG. 3 and its detection signal. 分割エリア毎の評価曲線と合計の評価曲線の説明図である。It is explanatory drawing of the evaluation curve for every division area, and a total evaluation curve. 分割エリア毎の評価曲線の信頼性説明図である。It is reliability explanatory drawing of the evaluation curve for every division area. 分割エリア毎の評価曲線のうち異なる被写体に対する評価曲線が求められた場合の多数決例の説明図である。It is explanatory drawing of the majority decision example when the evaluation curve with respect to a different subject is calculated | required among the evaluation curves for every divided area. 分割エリア毎の評価曲線のうち異なる被写体に対する評価曲線の数が同数となった場合の説明図である。It is explanatory drawing when the number of the evaluation curves with respect to a different subject becomes the same number among the evaluation curves for every divided area. 水平方向及び垂直方向を位相差検出方向とする位相差画素の説明図である。It is explanatory drawing of the phase difference pixel which makes a horizontal direction and a vertical direction a phase difference detection direction. 図９の位相差方向の説明図である。It is explanatory drawing of the phase difference direction of FIG. 図９の位相差検出画素を用いたときの位相差検出エリアの分割例を示す図である。It is a figure which shows the example of a division | segmentation of a phase difference detection area when using the phase difference detection pixel of FIG. 図９に示す分割エリア毎に求めた水平方向，垂直方向の評価曲線の一例を示す図である。It is a figure which shows an example of the evaluation curve of the horizontal direction calculated | required for every division area shown in FIG. 9, and a vertical direction.

以下、本発明の一実施形態について、図面を参照して説明する。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

図１は、本発明の一実施形態に係るデジタルカメラの機能ブロック図である。本実施形態のデジタルカメラ１０は、被写体の静止画像或いは動画像を撮影しカメラ１０内で撮像画像信号をデジタル処理する機能を有し、望遠レンズ及びフォーカスレンズを備える撮影レンズ２０と、撮影レンズ２０の背部に置かれその結像面に配置された固体撮像素子２１と、固体撮像素子２１の各画素から出力されるアナログの画像データを自動利得調整（ＡＧＣ）や相関二重サンプリング処理等のアナログ処理するアナログ信号処理部２２と、アナログ信号処理部２２から出力されるアナログ画像データをデジタル画像データに変換するアナログデジタル変換部（Ａ／Ｄ）２３と、後述のシステム制御部（ＣＰＵ）２９からの指示によってＡ／Ｄ２３，アナログ信号処理部２２，固体撮像素子２１，撮影レンズ２０の駆動制御を行う駆動制御部２４と、ＣＰＵ２９からの指示によって発光するフラッシュ２５とを備える。 FIG. 1 is a functional block diagram of a digital camera according to an embodiment of the present invention. The digital camera 10 of the present embodiment has a function of capturing a still image or a moving image of a subject and digitally processing a captured image signal in the camera 10, and includes a photographic lens 20 including a telephoto lens and a focus lens, and a photographic lens 20. The analog image data output from each pixel of the solid-state image sensor 21 and the solid-state image sensor 21 placed on the imaging surface of the solid-state image sensor 21 and the analog image data such as automatic gain adjustment (AGC) and correlated double sampling processing. From an analog signal processing unit 22 to be processed, an analog / digital conversion unit (A / D) 23 that converts analog image data output from the analog signal processing unit 22 into digital image data, and a system control unit (CPU) 29 described later The A / D 23, the analog signal processing unit 22, the solid-state imaging device 21, and the photographic lens 20 are driven and controlled by It comprises a dynamic controller 24, a flash 25 that emits light in response to an instruction from the CPU 29.

本実施形態のデジタルカメラ１０は更に、Ａ／Ｄ２３から出力されるデジタル画像データを取り込み補間処理やホワイトバランス補正，ＲＧＢ／ＹＣ変換処理等を行うデジタル信号処理部２６と、画像データをＪＰＥＧ形式などの画像データに圧縮したり逆に伸長したりする圧縮／伸長処理部２７と、メニューなどを表示したりスルー画像や撮像画像を表示する表示部２８と、デジタルカメラ全体を統括制御するシステム制御部（ＣＰＵ）２９と、フレームメモリ等の内部メモリ３０と、ＪＰＥＧ画像データ等を格納する記録メディア３２との間のインタフェース処理を行うメディアインタフェース（Ｉ／Ｆ）部３１と、これらを相互に接続するバス４０とを備え、また、システム制御部２９には、ユーザからの指示入力を行う操作部３３が接続されている。 The digital camera 10 according to the present embodiment further includes a digital signal processing unit 26 that takes in digital image data output from the A / D 23 and performs interpolation processing, white balance correction, RGB / YC conversion processing, and the like. A compression / decompression processing unit 27 that compresses or reversely decompresses the image data, a display unit 28 that displays a menu or the like, and a through image or a captured image, and a system control unit that performs overall control of the entire digital camera A media interface (I / F) unit 31 that performs interface processing between the (CPU) 29, an internal memory 30 such as a frame memory, and a recording medium 32 that stores JPEG image data, and the like are connected to each other. The system control unit 29 includes an operation unit 33 for inputting instructions from the user. It has been continued.

システム制御部２９は、固体撮像素子２１から動画状態で出力されデジタル信号処理部２６で処理された撮像画像データ（スルー画像）を配下のデジタル信号処理部２６等を用いて後述するように解析して評価曲線（相関演算曲線）を求め、主要被写体までの距離を検出する。そして、システム制御部２９は、駆動部２４を介し、撮影レンズ２０のうちのフォーカスレンズの位置制御を行い、被写体に合焦した光学像が固体撮像素子２１の受光面に結像するようにする。 The system control unit 29 analyzes the captured image data (through image) output from the solid-state imaging device 21 in a moving image state and processed by the digital signal processing unit 26 using the subordinate digital signal processing unit 26 and the like as described later. To obtain an evaluation curve (correlation calculation curve) and detect the distance to the main subject. Then, the system control unit 29 controls the position of the focus lens of the photographic lens 20 via the drive unit 24 so that an optical image focused on the subject is formed on the light receiving surface of the solid-state imaging device 21. .

固体撮像素子２１は、本実施形態ではＣＭＯＳ型であり、固体撮像素子２１の出力信号をアナログ信号処理部（ＡＦＥ：アナログフロントエンド）２２で処理するが、このＡＦＥ部分（相関二重サンプリング処理やクランプ処理を行う回路や利得制御を行う信号増幅回路等）は固体撮像素子チップ上に周辺回路として設けられるのが普通である。また、固体撮像素子２１のチップ上には、その他にも、水平走査回路や垂直走査回路、雑音低減回路，同期信号発生回路等が周辺回路として受光部周りに形成され、図１のＡ／Ｄ変換部２３も形成される場合がある。なお、固体撮像素子２１は、ＣＣＤ型でも、以下に説明する実施形態はそのまま適用可能である。 The solid-state image pickup device 21 is a CMOS type in this embodiment, and an output signal of the solid-state image pickup device 21 is processed by an analog signal processing unit (AFE: analog front end) 22, and this AFE portion (correlated double sampling processing or A circuit for performing a clamp process, a signal amplifier circuit for performing gain control, and the like) are generally provided as a peripheral circuit on a solid-state imaging device chip. In addition, a horizontal scanning circuit, a vertical scanning circuit, a noise reduction circuit, a synchronization signal generation circuit, and the like are also formed as peripheral circuits around the light receiving unit on the chip of the solid-state imaging device 21, and the A / D in FIG. The conversion part 23 may also be formed. The solid-state imaging device 21 may be a CCD type, and the embodiments described below can be applied as they are.

図２は、固体撮像素子２１の受光面の説明図である。固体撮像素子２１の受光面には、図示しない多数の画素（受光素子：フォトダイオード）が二次元アレイ状に配列形成されている。この実施形態では、複数の画素が正方格子状に配列形成されている。なお、画素配列は正方格子配列に限るものではなく、奇数行の画素行に対して偶数行の画素行が１／２画素ピッチづつずらして配列された、所謂、ハニカム配列でも良い。 FIG. 2 is an explanatory diagram of the light receiving surface of the solid-state imaging device 21. On the light receiving surface of the solid-state image sensor 21, a large number of pixels (light receiving elements: photodiodes) (not shown) are arranged in a two-dimensional array. In this embodiment, a plurality of pixels are arranged in a square lattice pattern. Note that the pixel arrangement is not limited to a square lattice arrangement, and may be a so-called honeycomb arrangement in which even-numbered pixel rows are shifted by 1/2 pixel pitch with respect to odd-numbered pixel rows.

受光面の任意の一部領域位置、図示する例では中央位置に、矩形の位相差検出エリア４０が設けられている。この例では、位相差検出エリア４０は受光面に対して１箇所だけ設けているが、撮影画面内のどこでもＡＦ可能とできるよう複数箇所に設けても良い。受光面の全領域を位相差検出エリアとすることでも良い。 A rectangular phase difference detection area 40 is provided at an arbitrary partial region position on the light receiving surface, in the illustrated example, at the center position. In this example, only one phase difference detection area 40 is provided with respect to the light receiving surface. However, the phase difference detection area 40 may be provided at a plurality of locations so that AF can be performed anywhere on the imaging screen. The entire area of the light receiving surface may be used as a phase difference detection area.

本実施形態では、位相差検出エリア４０を、位相差検出方向（この例では左右方向つまりｘ方向を位相差検出方向としている。）に対し垂直方向（上下方向ｙ）に４分割しており、各分割エリアＩ，II，III，IV毎に、後述の相関演算を行う構成となっている。なお、分割数は４つに限るものではなく、６分割でも７分割でも良く、任意数に分割できる。 In the present embodiment, the phase difference detection area 40 is divided into four in the vertical direction (up and down direction y) with respect to the phase difference detection direction (in this example, the left and right direction, that is, the x direction is the phase difference detection direction). For each of the divided areas I, II, III, and IV, a correlation calculation described later is performed. Note that the number of divisions is not limited to four, and may be six or seven, and can be divided into an arbitrary number.

図３は、位相差検出エリア４０内の、図２の点線矩形枠４１で示す部分の表面拡大模式図である。固体撮像素子２１の受光面には、多数の画素が正方格子配列されており、位相差検出エリア４０内でも同様である。 FIG. 3 is a schematic enlarged surface view of a portion indicated by a dotted rectangular frame 41 in FIG. 2 in the phase difference detection area 40. A large number of pixels are arranged in a square lattice on the light receiving surface of the solid-state imaging device 21, and the same applies to the phase difference detection area 40.

図示する例では、各画素をＲ（赤），Ｇ（緑），Ｂ（青）で示している。Ｒ，Ｇ，Ｂは各画素上に積層したカラーフィルタの色を表し、カラーフィルタ配列は、この例ではベイヤ配列となっているが、ベイヤ配列に限るものではなく、ストライプ等の他のカラーフィルタ配列でも良い。 In the illustrated example, each pixel is indicated by R (red), G (green), and B (blue). R, G, and B represent colors of the color filters stacked on each pixel, and the color filter array is a Bayer array in this example, but is not limited to the Bayer array, and other color filters such as stripes. An array may be used.

位相差検出エリア４０内の画素配列，カラーフィルタ配列は、位相差検出エリア４０外の受光面の画素配列，カラーフィルタ配列と同じであるが、位相差検出エリア４０内では、ペアを構成する斜めに隣接する同色画素を、位相差検出画素１ｘ，１ｙとしている。位相差検出用のペア画素は、本実施形態では、エリア４０内の離散的，周期的な位置、図示する例では市松位置に設けられている。 The pixel array and the color filter array in the phase difference detection area 40 are the same as the pixel array and the color filter array on the light receiving surface outside the phase difference detection area 40. Pixels of the same color adjacent to are designated as phase difference detection pixels 1x and 1y. In the present embodiment, paired pixels for phase difference detection are provided at discrete and periodic positions in the area 40, in the illustrated example, at checkered positions.

なお、図示する例では、カラーフィルタ配列がベイヤ配列のため同色画素が斜めに隣接するのであって、横ストライプ配列の場合には同色画素は水平方向に並ぶため、ペアを構成する２画素は横に隣接することになる。あるいは、横ストライプ配列で同じ色フィルタ行内にペアを構成する２画素を設けるのではなく、縦方向に最近接する同色のフィルタ行の夫々にペアを構成する各画素を離して設けることでも良い。縦ストライプ配列の場合も同様である。 In the illustrated example, the same color pixels are diagonally adjacent because the color filter array is a Bayer array, and in the case of a horizontal stripe array, the same color pixels are arranged in the horizontal direction. Will be adjacent to. Alternatively, instead of providing two pixels constituting a pair in the same color filter row in the horizontal stripe arrangement, each pixel constituting the pair may be provided separately in each filter row of the same color closest in the vertical direction. The same applies to the vertical stripe arrangement.

本実施形態では、位相差検出画素１ｘ，１ｙを、Ｒ，Ｇ，Ｂのうち最も多いＧフィルタ搭載画素に設けており、水平方向（ｘ方向）に８画素置き、垂直方向（ｙ方向）に８画素置き、かつ全体的に市松位置となるように配置されている。従って、位相差検出方向（左右方向）で見たとき、位相差検出画素１ｘは４画素置きに配置されることになる。 In the present embodiment, the phase difference detection pixels 1x and 1y are provided in the most G filter mounted pixels among R, G, and B, and 8 pixels are arranged in the horizontal direction (x direction) and in the vertical direction (y direction). It is arranged so that every eight pixels and the entire checkered position. Accordingly, when viewed in the phase difference detection direction (left-right direction), the phase difference detection pixels 1x are arranged every four pixels.

図４は、図３の位相差検出画素１ｘ，１ｙだけを抜き出して模式的に表示した図である。ペア画素を構成する位相差検出画素１ｘ，１ｙは、特許文献２と同様に、その遮光膜開口２ｘ，２ｙが他の画素（位相差検出画素以外の画素）より小さく形成され、かつ、画素１ｘの遮光膜開口２ｘは左方向に偏心して設けられ、画素１ｙの遮光膜開口２ｙは右方向（位相差検出方向）に偏心して設けられている。 FIG. 4 is a diagram schematically showing only the phase difference detection pixels 1x and 1y in FIG. Similarly to Patent Document 2, the phase difference detection pixels 1x and 1y constituting the paired pixels are formed such that the light shielding film openings 2x and 2y are smaller than other pixels (pixels other than the phase difference detection pixels), and the pixel 1x The light shielding film opening 2x is eccentrically provided in the left direction, and the light shielding film opening 2y of the pixel 1y is eccentrically provided in the right direction (phase difference detection direction).

図４の下段に示す曲線Ｘは、横一行に並ぶ位相差検出画素１ｘの検出信号量をプロットしたグラフであり、曲線Ｙは、これら画素１ｘとペアを構成する位相差検出画素１ｙの検出信号量をプロットしたグラフである。 The curve X shown in the lower part of FIG. 4 is a graph in which the detection signal amounts of the phase difference detection pixels 1x arranged in a horizontal row are plotted, and the curve Y is a detection signal of the phase difference detection pixel 1y that forms a pair with these pixels 1x. It is the graph which plotted quantity.

ペア画素１ｘ，１ｙは隣接画素であり極めて近接しているため、同一被写体からの光を受光していると考えられる。このため、曲線Ｘと曲線Ｙとは同一形状になると考えられ、その左右方向（位相差検出方向）のずれが、瞳分割したペア画素の一方の画素１ｘで見た画像と、他方の画素１ｙで見た画像との位相差量となる。 Since the pair pixels 1x and 1y are adjacent pixels and are very close to each other, it is considered that light from the same subject is received. For this reason, it is considered that the curve X and the curve Y have the same shape, and the shift in the left-right direction (phase difference detection direction) is caused by the difference between the image seen by one pixel 1x of the paired pixel divided by the pupil and the other pixel 1y. This is the amount of phase difference from the image seen in.

この曲線Ｘと曲線Ｙの相関演算を行うことで、位相差量（横ズレ量）を求めることができ、この位相差量から被写体までの距離を算出することが可能となる。曲線Ｘと曲線Ｙの相関量の評価値を求める方法は、公知の方法（例えば特許文献１に記載された方法や特許文献２に記載された方法）を採用すれば良い。例えば、曲線Ｘを構成する各点Ｘ（ｉ）と、曲線Ｙを構成する各点Ｙ（ｉ＋ｊ）の差分の絶対値の積算値を評価値とし、最大評価値を与えるｊ値を、位相差量（横ズレ量）とする。 By performing the correlation calculation between the curve X and the curve Y, the phase difference amount (lateral deviation amount) can be obtained, and the distance to the subject can be calculated from the phase difference amount. A known method (for example, a method described in Patent Document 1 or a method described in Patent Document 2) may be adopted as a method for obtaining the evaluation value of the correlation amount between the curve X and the curve Y. For example, the integrated value of the absolute value of the difference between each point X (i) constituting the curve X and each point Y (i + j) constituting the curve Y is used as the evaluation value, and the j value giving the maximum evaluation value is expressed as the phase difference. The amount (lateral deviation).

しかし、１画素１画素の受光面積が小さい場合、個々の信号量は小さくなってノイズの割合が増えるため、相関演算を行っても精度良く位相差量を検出することが困難となる。そこで、図２の位相差検出エリア４０内において、水平方向同一位置にある画素１ｘの検出信号を垂直方向に複数画素分だけ加算し、水平方向同一位置にある画素１ｙの検出信号を垂直方向に複数画素分だけ加算すれば、ノイズの影響を低減して合焦位置の検出精度（ＡＦ精度）を向上させることが可能となる。 However, when the light receiving area of each pixel is small, the amount of each signal is small and the ratio of noise is increased. Therefore, it is difficult to detect the phase difference with high accuracy even if correlation calculation is performed. Therefore, within the phase difference detection area 40 of FIG. 2, the detection signals of the pixels 1x at the same horizontal position are added by a plurality of pixels in the vertical direction, and the detection signals of the pixels 1y at the same horizontal position are added in the vertical direction. If only a plurality of pixels are added, the influence of noise can be reduced and the detection accuracy (AF accuracy) of the in-focus position can be improved.

しかし、画素加算数を多くすれば良いというものではなく、画素加算数が多くなるほど、それだけ位相差検出エリア４０の画素加算対象とする位相差検出画素の配置領域が上下方向（垂直方向）に延びることになる。被写体パターンは、位相差検出エリア４０の上部分で撮像されるパターンと中間部分で撮像されるパターンと下部分で撮像されるパターンとでは異なるのが普通である。このため、これらを全て画素加算してしまうと、位相差検出方向（左右方向）で被写体の画素加算後のパターンが平均化されてしまい、位相差を求める評価値が下がってしまうという問題が生じる。 However, it is not necessary to increase the number of pixel additions. As the number of pixel additions increases, the arrangement area of the phase difference detection pixels to be added to the pixels in the phase difference detection area 40 extends in the vertical direction (vertical direction). It will be. The subject pattern is usually different between a pattern imaged in the upper part of the phase difference detection area 40, a pattern imaged in the middle part, and a pattern imaged in the lower part. For this reason, if all these pixels are added, the pattern after subject pixel addition is averaged in the phase difference detection direction (left and right direction), resulting in a problem that the evaluation value for obtaining the phase difference is lowered. .

そこで、本実施形態では、図２に示す様に、位相差検出エリア４０を４分割し、画素加算範囲を各分割エリア内に限定し、分割エリアを超えて画素加算しない様にしている。つまり、各分割エリアＩ，II，III，IV毎に画素加算して分割エリア評価曲線（相関演算カーブ）を求め、各分割エリア評価曲線を加算して位相差検出エリア４０の全体の評価曲線（全エリア評価曲線）を求めることとしている。 Therefore, in the present embodiment, as shown in FIG. 2, the phase difference detection area 40 is divided into four, the pixel addition range is limited to each divided area, and pixel addition is not performed beyond the divided area. In other words, pixels are added to each divided area I, II, III, IV to obtain a divided area evaluation curve (correlation calculation curve), and each divided area evaluation curve is added to evaluate the entire evaluation curve of the phase difference detection area 40 ( All area evaluation curve).

図５には、分割エリア毎の夫々の評価曲線Ｉ，II，III，IVと、これら４本の分割エリア評価曲線を合計した全エリア評価曲線（全エリアの相関演算曲線）Ｖを示すグラフである。分割エリア評価曲線Ｉは、分割領域Ｉ内で位相差検出画素１ｘの検出信号を垂直方向（例えば図３の符号４５）に画素加算して得られた図４の曲線Ｘと、同じく分割領域Ｉ内で位相差検出画素１ｙの検出信号を垂直方向（例えば図３の符号４６）に画素加算して得られた図４の曲線Ｙとを相関演算して求めた評価曲線である。この例の場合、最大評価値は最小値として求められる。 FIG. 5 is a graph showing the respective evaluation curves I, II, III, IV for each divided area and the total area evaluation curve (correlation calculation curve for all areas) V obtained by adding up these four divided area evaluation curves. is there. The divided area evaluation curve I is the same as the divided area I in FIG. 4 obtained by adding the detection signals of the phase difference detection pixels 1x in the divided area I in the vertical direction (for example, reference numeral 45 in FIG. 3). 4 is an evaluation curve obtained by correlation calculation with the curve Y in FIG. 4 obtained by adding the detection signals of the phase difference detection pixel 1y in the vertical direction (for example, reference numeral 46 in FIG. 3). In this example, the maximum evaluation value is obtained as the minimum value.

同じく、分割エリア評価曲線IIは分割領域IIで得られた評価曲線であり、分割エリア評価曲線IIIは分割領域IIIで得られた評価曲線であり、分割エリア評価曲線IVは分割領域IVで得られた評価曲線である。 Similarly, the divided area evaluation curve II is an evaluation curve obtained in the divided area II, the divided area evaluation curve III is an evaluation curve obtained in the divided area III, and the divided area evaluation curve IV is obtained in the divided area IV. It is an evaluation curve.

これら４本の分割エリア評価曲線Ｉ，II，III，IVの各々を求めるための加算画素数は、位相差検出エリア４０の垂直方向に並ぶ位相差検出画素１ｘの画素数に対して、ほぼ分割エリア数分の１となるため、被写体のパターンが平均化される虞が少なく、精度良く評価値を算出することが可能となる。 The number of added pixels for obtaining each of these four divided area evaluation curves I, II, III, and IV is substantially divided with respect to the number of phase difference detection pixels 1x arranged in the vertical direction of the phase difference detection area 40. Since the number of areas is one-thousand, there is little possibility that the subject pattern is averaged, and the evaluation value can be calculated with high accuracy.

そして、本実施形態では、これら４本の分割エリア評価曲線Ｉ，II，III，IVを合計した全エリア評価曲線Ｖを求め、更に、全エリア評価曲線Ｖからサブピクセル補間演算を行うことで、位相差量（デフォーカス量）を求める。これにより、ノイズに強く、かつ被写体の各分割エリア毎の評価値を保ったまま位相差の高精度な演算が可能となり、ＡＦ精度の向上を図ることが可能となる。 In the present embodiment, the total area evaluation curve V obtained by totaling these four divided area evaluation curves I, II, III, and IV is obtained, and further, sub-pixel interpolation is performed from the total area evaluation curve V. The phase difference amount (defocus amount) is obtained. This makes it possible to perform highly accurate calculation of the phase difference while being resistant to noise and maintaining the evaluation value for each divided area of the subject, thereby improving the AF accuracy.

図５のグラフの横軸の１単位は、図３の位相差検出画素の画素間隔（８画素間隔の市松配列であるため、４画素間隔となる。）であるため、全エリア評価曲線Ｖの最小値の位置と、この最小値に対して右側に延びる曲線と左側に延びる曲線の夫々の勾配等を勘案して、真の最小値（最大評価値）を与える位置つまり位相差量をサブピクセル補間演算で算出する。これにより、図３の一画素単位で位相差量を求めることが可能となる。 Since one unit of the horizontal axis of the graph of FIG. 5 is the pixel interval of the phase difference detection pixels of FIG. 3 (because of the checkered array of 8 pixel intervals, the interval is 4 pixels), Considering the position of the minimum value and the gradient of the curve extending to the right and the curve extending to the left side relative to this minimum value, the position that gives the true minimum value (maximum evaluation value), that is, the phase difference amount is subpixel. Calculate by interpolation. As a result, the phase difference amount can be obtained for each pixel in FIG.

上述した実施形態では、４本の分割エリア評価曲線Ｉ，II，III，IVを合計して全エリア評価曲線Ｖを求め、最大評価値を求めるとして説明した。しかし、各分割エリアＩ，II，III，IV毎に相関演算を行った場合、信頼性の低い相関演算結果しか得られない分割エリアも存在することがある。 In the above-described embodiment, the four divided area evaluation curves I, II, III, and IV are totaled to obtain the entire area evaluation curve V, and the maximum evaluation value is obtained. However, when the correlation calculation is performed for each of the divided areas I, II, III, and IV, there may be a divided area where only a correlation calculation result with low reliability can be obtained.

例えば、図６に示す様に、相関カーブ（評価曲線）IIだけみたとき、最大評価値（この例では最小値）を与える横軸位置が明確でなく不明（例えば複数点の存在）の場合が存在する。この様な場合には、信頼性の低い相関カーブII以外の、信頼性の高い相関カーブＩ，III，IVの３本の相関カーブだけを加算して合計の全エリア評価曲線（分割領域Ｉの相関演算曲線は使っていないため「全」エリアではなく複数エリアの相関演算曲線であるが、便宜上、「全エリア評価曲線」という。）Ｖを求め、この全エリア評価曲線Ｖをサブピクセル補間処理し、位相差量つまりデフォーカス量を算出する。これにより、ＡＦ精度の更なる向上を図ることが可能となる。 For example, as shown in FIG. 6, when only the correlation curve (evaluation curve) II is viewed, the position of the horizontal axis that gives the maximum evaluation value (minimum value in this example) is not clear and unknown (for example, the presence of a plurality of points). Exists. In such a case, except for the correlation curve II with low reliability, only the three correlation curves I, III, and IV with high reliability are added to obtain a total total area evaluation curve (for the divided region I). Since the correlation calculation curve is not used, it is a correlation calculation curve for a plurality of areas instead of the “all” area, but for convenience, it is referred to as “all area evaluation curve”) V is obtained, and this all area evaluation curve V is sub-pixel interpolated. Then, the phase difference amount, that is, the defocus amount is calculated. Thereby, it is possible to further improve the AF accuracy.

信頼性が高いか否かは、信頼性を数値化しこれが所定閾値より高いか否かで判定する。例えば、１本の分割エリア評価曲線に評価値が同程度の最小値となる極小値が複数存在したとき、信頼性が低いと判断する。 Whether or not the reliability is high is determined by quantifying the reliability and determining whether or not the reliability is higher than a predetermined threshold. For example, when there are a plurality of minimum values that have the same minimum evaluation value in a single divided area evaluation curve, it is determined that the reliability is low.

図２の位相差検出エリア４０内に撮影距離の異なる複数の被写体が存在する場合がある。仮に、被写体Ａ，Ｂが存在するとする。この様な場合、例えば図７に示す様に、分割エリアＩ，II，IIIでは被写体Ａに対して最大評価値を出す評価曲線Ｉ，II，IIIが算出され、分割エリアIVでは被写体Ｂに対して最大評価値を出す評価曲線IVが算出される。図６の場合と異なり、図７の評価曲線IVは、信頼性が低い訳ではなく、信頼性は高い。 There may be a plurality of subjects with different shooting distances in the phase difference detection area 40 of FIG. Assume that subjects A and B exist. In such a case, for example, as shown in FIG. 7, in the divided areas I, II, and III, evaluation curves I, II, and III for calculating the maximum evaluation value for the subject A are calculated, and in the divided area IV, for the subject B. Thus, an evaluation curve IV for obtaining the maximum evaluation value is calculated. Unlike the case of FIG. 6, the evaluation curve IV of FIG. 7 is not necessarily low in reliability but high in reliability.

しかし、この様な場合に、全部の分割エリア評価曲線Ｉ，II，III，IVを合計して全エリア評価曲線Ｖを求めると誤合焦となり、合焦位置を誤る虞がある。そこで、この様な場合には、個々の評価曲線Ｉ，II，III，IVの最大評価値をとる横軸上の位置（精確な位置ではなく、ある程度の同範囲内にあると考えられる位置で良い。）の多数決をとり、分割エリア評価曲線IVを除外し、多数となる分割エリア評価曲線Ｉ，II，IIIを合計することで全エリア評価曲線Ｖを求める。これにより、位相差検出エリア（ＡＦエリア）に撮影距離の異なる被写体が存在しても、誤合焦を防ぐことが可能となる。 However, in such a case, if all the divided area evaluation curves I, II, III, and IV are totaled to obtain the whole area evaluation curve V, there is a possibility that the in-focus position may be incorrect. Therefore, in such a case, a position on the horizontal axis that takes the maximum evaluation value of each evaluation curve I, II, III, IV (not a precise position, but a position that is considered to be within a certain range of some extent). The total area evaluation curve V is obtained by adding the majority of the divided area evaluation curves I, II, and III. As a result, even when subjects with different shooting distances exist in the phase difference detection area (AF area), it is possible to prevent erroneous focusing.

図７の説明では、４本の分割エリア評価曲線の多数決をとるとして説明した。しかし、分割エリア数が４個であるため、２対２の同数となる場合も存在する。この場合を図８で説明する。図８では、分割エリア評価曲線Ｉ，III（被写体Ａに対する評価曲線とする。）と、分割エリア評価曲線II，IV（被写体Ｂに対する評価曲線とする。）の２本づつとなっている。 In the description of FIG. 7, it is assumed that the majority of the four divided area evaluation curves is taken. However, since the number of divided areas is 4, there may be a case where the number is equal to 2 to 2. This case will be described with reference to FIG. In FIG. 8, there are two divided area evaluation curves I and III (the evaluation curves for the subject A) and divided area evaluation curves II and IV (the evaluation curves for the subject B).

この様な場合に、４本の分割エリア評価曲線Ｉ，II，III，IVを合計して全エリア評価曲線Ｖを求めると、被写体Ａにも合焦せず、被写体Ｂにも合焦しない結果になってしまう。そこで、被写体Ａか被写体Ｂのいずれか一方を選ぶことになる。本実施形態では、被写体Ａと被写体Ｂのうち、カメラに近い側の被写体を主要被写体と判断することにする。つまり、位置ズレ量が小さい側（図５の横軸参照：撮像装置に近い側）の被写体を選択し、分割エリア評価曲線Ｉ，IIIだけを加算して全エリア評価曲線Ｖを求め、サブピクセル補間して位相差量を算出する。 In such a case, when the total area evaluation curve V is obtained by adding the four divided area evaluation curves I, II, III, and IV, the subject A is not focused and the subject B is not focused. Become. Therefore, either subject A or subject B is selected. In the present embodiment, of the subjects A and B, the subject closer to the camera is determined as the main subject. That is, the subject on the side where the amount of positional deviation is small (see the horizontal axis in FIG. 5: the side close to the imaging device) is selected, and only the divided area evaluation curves I and III are added to obtain the entire area evaluation curve V, thereby subpixels. The phase difference amount is calculated by interpolation.

これにより、ＡＦエリアに撮影距離の異なる被写体が存在する場合でも、誤合焦を防ぐことが可能となり、かつ、近い被写体に優先的にＡＦを合わせることが可能となる。 As a result, even when subjects with different shooting distances exist in the AF area, it is possible to prevent erroneous focusing, and it is possible to preferentially focus AF on a close subject.

図９は、本発明の別実施形態に係る位相差検出画素の画素配列を示す図である。上述した各実施形態では、位相差検出方向を横方向（ｘ方向）だけとして位相差検出画素１ｘ，１ｙを設けたが、本実施形態では、図１０に示す様に、横方向を第１位相差検出方向とし、縦方向（ｙ方向）も第２位相差検出方向としている。 FIG. 9 is a diagram showing a pixel arrangement of phase difference detection pixels according to another embodiment of the present invention. In each of the embodiments described above, the phase difference detection pixels 1x and 1y are provided with only the phase difference detection direction as the horizontal direction (x direction). However, in this embodiment, as shown in FIG. The phase difference detection direction is used, and the vertical direction (y direction) is also the second phase difference detection direction.

このため、図９に示す様に、この実施形態では、正方配列の最隣接４画素Ａ，Ｂ，Ｃ，Ｄのうち、左上画素Ａ（位相差画素１ｘに相当）と右下画素Ｂ（位相差画素１ｙに相当）とで水平方向（ｘ方向）の位相差を検出し、右上画素Ｃと左下画素Ｄとで垂直方向（ｙ方向）の位相差を検出する構成となっている。即ち、画素Ａの小さな遮光膜開口を左側に偏心させ、画素Ｂの小さな遮光膜開口を右側に偏心させ、画素Ｃの小さな遮光膜開口を上側に偏心させ、画素Ｄの小さな遮光膜開口を下側に偏心させている。 For this reason, as shown in FIG. 9, in this embodiment, among the four adjacent pixels A, B, C, and D in the square array, the upper left pixel A (corresponding to the phase difference pixel 1x) and the lower right pixel B (position) The phase difference in the horizontal direction (x direction) is detected by the phase difference pixel 1y), and the phase difference in the vertical direction (y direction) is detected by the upper right pixel C and the lower left pixel D. That is, the small light shielding film opening of the pixel A is decentered to the left side, the small light shielding film opening of the pixel B is decentered to the right side, the small light shielding film opening of the pixel C is decentered upward, and the small light shielding film opening of the pixel D is It is eccentric to the side.

上述した図９に示す位相差検出画素Ａ，Ｂ，Ｃ，Ｄの組を、図１０の位相差検出エリア４０内の周期的かつ離散的位置に配列することで、縦方向，横方向の位相差を検出する。この場合、矩形の位相差検出エリア４０をメッシュ状に、図１１に示す例では縦横共に２分割の計４つのエリアＩ，II，III，IVに分割する。この４つの分割エリアの夫々では、同一エリア内で縦方向，横方向共に同じ様な評価曲線が得られる蓋然性が高いと考えられる。 By arranging the set of the phase difference detection pixels A, B, C, and D shown in FIG. 9 at periodic and discrete positions in the phase difference detection area 40 of FIG. 10, the vertical and horizontal positions are arranged. Detect phase difference. In this case, the rectangular phase difference detection area 40 is divided into a mesh shape, and is divided into four areas I, II, III, and IV in the example shown in FIG. Each of the four divided areas is considered to have a high probability of obtaining the same evaluation curve in the vertical and horizontal directions within the same area.

図１２は、４つの分割エリアの夫々で水平方向の分割エリア評価曲線と垂直方向の分割エリア評価曲線の計８本の分割エリア評価曲線を求めた場合の一例を示す図である。分割エリアＩからは、水平方向の分割エリア評価曲線Ｉａと垂直方向の分割エリア評価曲線Ｉｂが求まり、分割エリアIIからは、水平方向の分割エリア評価曲線IIａと垂直方向の分割エリア評価曲線IIｂが求まり、分割エリアIIIからは、水平方向の分割エリア評価曲線IIIａと垂直方向の分割エリア評価曲線IIIｂが求まり、分割エリアIVからは、水平方向の分割エリア評価曲線IVａと垂直方向の分割エリア評価曲線IVｂが求まる。 FIG. 12 is a diagram illustrating an example of a case where a total of eight divided area evaluation curves, that is, a divided area evaluation curve in the horizontal direction and a divided area evaluation curve in the vertical direction, are obtained in each of the four divided areas. From the divided area I, a horizontal divided area evaluation curve Ia and a vertical divided area evaluation curve Ib are obtained, and from the divided area II, a horizontal divided area evaluation curve IIa and a vertical divided area evaluation curve IIb are obtained. From the divided area III, a horizontal divided area evaluation curve IIIa and a vertical divided area evaluation curve IIIb are obtained, and from the divided area IV, the horizontal divided area evaluation curve IVa and the vertical divided area evaluation curve are obtained. IVb is obtained.

図１２の例では、分割エリアIVの評価値の信頼性が小さいため、分割エリアＩ，II，IIIの計６本の分割エリア評価曲線を加算して合計の全エリア評価曲線Ｖを求め、サブピクセル補間を行い、位相差量つまりデフォーカス量を算出する。この様に、異なる方向の位相差を検出して合焦位置を求めるため、ＡＦ精度の更なる向上を図ることが可能となる。また、信頼性の低い分割エリアを除外してＡＦ演算には用いないため、ＡＦ精度を更に向上させることができる。 In the example of FIG. 12, since the reliability of the evaluation value of divided area IV is small, a total of six divided area evaluation curves for divided areas I, II, and III are added to obtain a total total area evaluation curve V. Pixel interpolation is performed to calculate a phase difference amount, that is, a defocus amount. In this way, since the in-focus position is obtained by detecting the phase difference in different directions, it is possible to further improve the AF accuracy. Further, since the divided areas with low reliability are excluded and are not used for the AF calculation, the AF accuracy can be further improved.

以上述べた実施形態の様に、位相差検出エリアを複数領域に分割し、分割エリア毎に分割エリア評価曲線を求め、信頼性の高い分割エリア評価曲線だけを加算して合計の全エリア評価曲線を求め、この全エリア評価曲線をサブピクセル補間して位相差量を算出し撮影レンズの合焦制御を行うため、小面積の撮像素子を使用する場合であっても一眼レフカメラと同程度の高速かつ高精度なＡＦ性能を得ることが可能となる。 As in the embodiment described above, the phase difference detection area is divided into a plurality of areas, a divided area evaluation curve is obtained for each divided area, and only a highly reliable divided area evaluation curve is added to obtain a total total area evaluation curve. The total area evaluation curve is sub-pixel interpolated to calculate the amount of phase difference and control the focus of the photographic lens, so even when using a small area image sensor, it is comparable to a single-lens reflex camera. High-speed and high-precision AF performance can be obtained.

なお、上述した実施形態では、位相差検出画素を構成する瞳分割したペア画素として、小さくした遮光膜開口を互いに反対方向にずらした例を用いて説明したが、瞳分割して位相差検出画素を構成する方法はこれに限るものではなく、例えばペア画素に一つのマイクロレンズを搭載して瞳分割することでも良い。 In the above-described embodiment, the pupil-divided pair pixel constituting the phase difference detection pixel has been described by using an example in which the reduced light shielding film openings are shifted in opposite directions. The method of configuring is not limited to this, and for example, one microlens may be mounted on a pair of pixels to divide the pupil.

また、上述した実施形態では、個々のエリア毎の相関演算曲線に対し所要演算処理を施して全エリア（或いは複数エリア）評価曲線を求める場合、所要演算処理として「加算合計」する例について述べたが、他にも、「平均値」や「乗算値」を求めることでも良い。 Further, in the above-described embodiment, an example in which “addition and summation” is performed as the required calculation process when the required calculation process is performed on the correlation calculation curve for each area to obtain an evaluation curve for all areas (or a plurality of areas) has been described. However, “average value” and “multiplication value” may be obtained in addition.

更に、上述した実施形態では、位相差を検出するペア画素を位相差検出エリア内の離散的，周期的な位置に設けた例について述べたが、必ずしも周期的，離散的位置に設ける必要はなく、ランダムな位置（同一行に設けられる位相差検出画素がランダムな位置にあっても図４の曲線Ｘ，Ｙは求められる。）であっても良く、あるいは全画素を位相差検出画素とすることでも良い。 Furthermore, in the above-described embodiment, the example in which the pair pixels for detecting the phase difference are provided at discrete and periodic positions in the phase difference detection area has been described. However, the pixel need not necessarily be provided at the periodic and discrete positions. 4 may be random positions (even if the phase difference detection pixels provided in the same row are at random positions, the curves X and Y in FIG. 4 can be obtained), or all the pixels are used as phase difference detection pixels. That's fine.

以上述べた実施形態の撮像装置及びその合焦位置検出方法は、被写体の画像を撮像する受光面に設けられた位相差検出エリア内に、瞳分割した第１の位相差検出画素及び第２の位相差検出画素で構成されるペア画素が配列形成された撮像素子と、
該撮像素子の前段に置かれ、前記被写体の合焦した光学像を前記受光面に結像させるフォーカスレンズと、
前記第１の位相差検出画素の検出情報と前記第２の位相差検出画素の検出情報との位相差を求め、該位相差に基づき前記フォーカスレンズを前記合焦する位置に制御する制御手段とを備える撮像装置及びその合焦位置検出方法であって、
前記位相差の検知方向に対して直角方向に前記位相差検出エリアを複数の分割エリアに分割し、
前記分割エリア毎に、当該分割エリア内の前記直角方向に一列に並ぶ複数の前記第１の位相差検出画素の出力信号を、該分割エリア内の前記位相差を検出する方向に並ぶ複数の前記第１の位相差検出画素毎に加算すると共に、前記直角方向に一列に並ぶ複数の前記第２の位相差検出画素の出力信号を、該分割エリア内の前記位相差を検出する方向に並ぶ複数の前記第２の位相差検出画素毎に加算し、
前記分割エリア毎に、前記第１の位相差検出画素の前記加算した信号と前記第２の位相差検出画素の前記加算した信号との相関関係を演算して分割エリア毎の相関演算曲線を算出し、
前記分割エリア毎に算出された前記分割エリア毎の相関演算曲線のうち任意複数個の前記相関演算曲線間に所定演算処理を施して複数エリアの相関演算曲線を求め、該複数エリアの相関演算曲線から前記フォーカスレンズを前記合焦位置に制御する位相差を求める
ことを特徴とする。 The imaging apparatus and the focus position detection method thereof according to the embodiments described above include the first phase difference detection pixel and the second phase divided in the phase difference detection area provided on the light receiving surface that captures the image of the subject. An image sensor in which a pair of pixels composed of phase difference detection pixels are arrayed;
A focus lens that is placed in front of the image sensor and forms a focused optical image of the subject on the light receiving surface;
Control means for obtaining a phase difference between detection information of the first phase difference detection pixel and detection information of the second phase difference detection pixel, and controlling the focus lens to the in-focus position based on the phase difference; An imaging apparatus including the same and a focusing position detection method thereof,
Dividing the phase difference detection area into a plurality of divided areas in a direction perpendicular to the phase difference detection direction;
For each of the divided areas, the output signals of the plurality of first phase difference detection pixels arranged in a line in the perpendicular direction in the divided area are output in the direction in which the phase difference in the divided area is detected. A plurality of first phase difference detection pixels are added and a plurality of second phase difference detection pixel output signals arranged in a line in the perpendicular direction are arranged in a direction in which the phase difference in the divided area is detected. For each of the second phase difference detection pixels,
For each divided area, a correlation calculation curve for each divided area is calculated by calculating a correlation between the added signal of the first phase difference detection pixel and the added signal of the second phase difference detection pixel. And
A correlation calculation curve for a plurality of areas is obtained by performing a predetermined calculation process between the plurality of correlation calculation curves among the correlation calculation curves for each of the divided areas calculated for each of the divided areas. To obtain a phase difference for controlling the focus lens to the in-focus position.

また、実施形態の撮像装置及びその合焦位置検出方法は、前記複数エリアの相関演算曲線を算出するとき前記分割エリア毎の各相関演算曲線の信頼性評価を行い、信頼性が所定閾値より高い前記分割エリア毎の相関演算曲線に対してだけ前記所定演算処理を施して前記複数エリアの相関演算曲線を求めることを特徴とする。 In the imaging apparatus and the focus position detection method according to the embodiment, when calculating the correlation calculation curves of the plurality of areas, the reliability of each correlation calculation curve for each divided area is evaluated, and the reliability is higher than a predetermined threshold. The correlation calculation curves for the plurality of areas are obtained by performing the predetermined calculation process only on the correlation calculation curves for the divided areas.

また、実施形態の撮像装置及びその合焦位置検出方法は、前記分割エリア毎の相関演算曲線の最大評価値を与える位置が同程度の範囲内となる分割エリア毎の相関演算曲線だけを用いて前記複数エリアの相関演算曲線を求めることを特徴とする。 In addition, the imaging apparatus and the focus position detection method of the embodiment use only the correlation calculation curve for each divided area in which the position for giving the maximum evaluation value of the correlation calculation curve for each divided area is within the same range. A correlation calculation curve for the plurality of areas is obtained.

また、実施形態の撮像装置及びその合焦位置検出方法は、各分割エリア毎の相関演算曲線の前記最大評価値を与える位置の多数決をとり、多数となる前記分割エリア毎の相関演算曲線だけを用いて前記複数エリアの相関演算曲線を求めることを特徴とする。 In addition, the imaging apparatus and the focus position detection method of the embodiment take a majority decision of the position that gives the maximum evaluation value of the correlation calculation curve for each divided area, and obtain only a large number of correlation calculation curves for each divided area. And calculating a correlation calculation curve of the plurality of areas.

また、実施形態の撮像装置及びその合焦位置検出方法は、前記最大評価値を与える位置が同程度の範囲内となる数が複数となり前記複数エリアの相関演算曲線が複数求まるときは、前記最大評価値を与える位置の位相差ズレ量が小さい方の前記複数エリアの相関演算曲線を選択することを特徴とする。 Further, in the imaging apparatus and the focus position detection method of the embodiment, when the number of positions where the maximum evaluation value is given is within a similar range and a plurality of correlation calculation curves of the plurality of areas are obtained, the maximum The correlation calculation curve of the plurality of areas having the smaller phase difference shift amount at the position where the evaluation value is given is selected.

また、実施形態の撮像装置及びその合焦位置検出方法は、前記最大評価値を与える位置が同程度の範囲内となる数が複数となり前記複数エリアの相関演算曲線が複数求まるときは、前記最大評価値を与える位置が前記撮像素子から近い方の前記複数エリアの相関演算曲線を選択することを特徴とする。 Further, in the imaging apparatus and the focus position detection method of the embodiment, when the number of positions where the maximum evaluation value is given is within a similar range and a plurality of correlation calculation curves of the plurality of areas are obtained, the maximum The correlation calculation curve of the plurality of areas whose position where the evaluation value is given is closer to the image sensor is selected.

また、実施形態の撮像装置及びその合焦位置検出方法は、水平方向の位相差を検出する前記第１の位相差検出画素及び前記第２の位相差検出画素のペア画素の他に垂直方向の位相差を検出する前記第１の位相差検出画素及び前記第２の位相差検出画素のペア画素を前記撮像素子の前記位相差検出エリア内に設け、前記位相差検出エリアをメッシュ状に複数の分割エリアに分割し、各分割エリア毎に、前記水平方向の前記分割エリア毎の相関演算曲線と前記垂直方向の前記分割エリア毎の相関演算曲線とを求め、分割エリア数の２倍の数の前記分割エリア毎の相関演算曲線に基づいて前記複数エリアの相関演算曲線を求めることを特徴とする。 In addition, in the imaging apparatus and the focus position detection method thereof according to the embodiment, in addition to the pair of pixels of the first phase difference detection pixel and the second phase difference detection pixel that detect the phase difference in the horizontal direction, A pair pixel of the first phase difference detection pixel and the second phase difference detection pixel for detecting a phase difference is provided in the phase difference detection area of the image sensor, and the phase difference detection area is formed in a plurality of mesh shapes. Dividing into divided areas, for each divided area, obtain a correlation calculation curve for each of the divided areas in the horizontal direction and a correlation calculation curve for each of the divided areas in the vertical direction, and have twice the number of divided areas. A correlation calculation curve for the plurality of areas is obtained based on a correlation calculation curve for each of the divided areas.

また、実施形態の撮像装置及びその合焦位置検出方法は、前記２倍の数の前記分割エリア毎の相関演算曲線のうち、同一分割エリアにおける前記水平方向の分割エリア毎の相関演算曲線と前記垂直方向の分割エリア毎の相関演算曲線とが異なる最大評価値を持つ場合には当該分割エリアの２本の分割エリア毎の相関演算曲線を除外した残りの分割エリア毎の相関演算曲線から前記複数エリアの相関演算曲線を求めることを特徴とする。 In addition, the imaging apparatus and the focus position detection method according to the embodiment include the correlation calculation curve for each of the horizontal divided areas in the same divided area among the two times as many correlation calculation curves for each of the divided areas, and the above-described correlation calculation curve. If the correlation calculation curve for each divided area in the vertical direction has a different maximum evaluation value, the plurality of correlation calculation curves for the remaining divided areas excluding the correlation calculation curves for the two divided areas of the divided area An area correlation calculation curve is obtained.

以上述べた実施形態によれば、分割エリア毎に画素加算を行うため、画素加算数が多くなって被写体のパターンが平均化されていることがなく、また、画素加算を行うために精度の高い位相差量を検出でき、小型小面積の固体撮像素子であっても高速かつ高精度に位相差ＡＦを実現可能となる。 According to the embodiment described above, since pixel addition is performed for each divided area, the number of pixel additions is increased and the pattern of the subject is not averaged, and the pixel addition is highly accurate. The phase difference amount can be detected, and the phase difference AF can be realized at high speed and with high accuracy even with a small and small area solid-state imaging device.

本発明に係る合焦位置検出方法は、高速かつ高精度なＡＦ性能を得ることができるため、デジタルカメラ特にコンパクトなデジタルカメラやカメラ付携帯電話機、カメラ付電子装置、内視鏡用撮像装置等に適用すると有用である。 Since the in-focus position detection method according to the present invention can obtain high-speed and high-precision AF performance, a digital camera, particularly a compact digital camera, a camera-equipped mobile phone, an electronic device with a camera, an imaging device for an endoscope, etc. It is useful to apply to.

１ｘ，１ｙ位相差検出画素
２ｘ，２ｙ位相差検出画素の遮光膜開口
１０撮像装置
２０撮影レンズ
２１固体撮像素子
２４駆動部
２６デジタル信号処理部
２９システム制御部
４０位相差検出エリア
Ｉ，II，III，IV 分割エリア 1x, 1y Phase difference detection pixels 2x, 2y Light shielding film opening 10 of phase difference detection pixels Imaging device 20 Shooting lens 21 Solid-state imaging device 24 Drive unit 26 Digital signal processing unit 29 System control unit 40 Phase difference detection areas I, II, III , IV Divided area

Claims

被写体の画像を撮像する受光面に設けられた位相差検出エリア内に、瞳分割した第１の位相差検出画素及び第２の位相差検出画素で構成されるペア画素が配列形成された撮像素子と、
該撮像素子の前段に置かれ、前記被写体の合焦した光学像を前記受光面に結像させるフォーカスレンズと、
前記第１の位相差検出画素の検出情報と前記第２の位相差検出画素の検出情報との位相差を求め、該位相差に基づき前記フォーカスレンズを前記合焦する位置に制御する制御手段とを備え、
該制御手段は、
前記位相差の検知方向に対して直角方向に前記位相差検出エリアを複数の分割エリアに分割する手段と、
前記分割エリア毎に、当該分割エリア内の前記直角方向に一列に並ぶ複数の前記第１の位相差検出画素の出力信号を、該分割エリア内の前記位相差を検出する方向に並ぶ複数の前記第１の位相差検出画素毎に加算すると共に、前記直角方向に一列に並ぶ複数の前記第２の位相差検出画素の出力信号を、該分割エリア内の前記位相差を検出する方向に並ぶ複数の前記第２の位相差検出画素毎に加算する手段と、
前記分割エリア毎に、前記第１の位相差検出画素の前記加算した信号と前記第２の位相差検出画素の前記加算した信号との相関関係を演算して分割エリア毎の相関演算曲線を算出する手段と、
前記分割エリア毎に算出された前記分割エリア毎の相関演算曲線のうち任意複数個の前記相関演算曲線間に所定演算処理を施して複数エリアの相関演算曲線を求め、該複数エリアの相関演算曲線から前記フォーカスレンズを前記合焦位置に制御する位相差を求める手段と
を備える撮像装置。 An imaging element in which a pair of pixels composed of a first phase difference detection pixel and a second phase difference detection pixel divided into pupils are arrayed in a phase difference detection area provided on a light receiving surface for picking up an image of a subject. When,
A focus lens that is placed in front of the image sensor and forms a focused optical image of the subject on the light receiving surface;
Control means for obtaining a phase difference between detection information of the first phase difference detection pixel and detection information of the second phase difference detection pixel, and controlling the focus lens to the in-focus position based on the phase difference; With
The control means includes
Means for dividing the phase difference detection area into a plurality of divided areas in a direction perpendicular to the phase difference detection direction;
For each of the divided areas, the output signals of the plurality of first phase difference detection pixels arranged in a line in the perpendicular direction in the divided area are output in the direction in which the phase difference in the divided area is detected. A plurality of first phase difference detection pixels are added and a plurality of second phase difference detection pixel output signals arranged in a line in the perpendicular direction are arranged in a direction in which the phase difference in the divided area is detected. Means for adding each of the second phase difference detection pixels;
For each divided area, a correlation calculation curve for each divided area is calculated by calculating a correlation between the added signal of the first phase difference detection pixel and the added signal of the second phase difference detection pixel. Means to
A correlation calculation curve for a plurality of areas is obtained by performing a predetermined calculation process between the plurality of correlation calculation curves among the correlation calculation curves for each of the divided areas calculated for each of the divided areas. An imaging device comprising: a phase difference for controlling the focus lens to the in-focus position.

請求項１に記載の撮像装置であって、前記複数エリアの相関演算曲線を算出するとき前記分割エリア毎の各相関演算曲線の信頼性評価を行い、信頼性が所定閾値より高い前記分割エリア毎の相関演算曲線に対してだけ前記所定演算処理を施して前記複数エリアの相関演算曲線を求めることを特徴とする撮像装置。 2. The imaging apparatus according to claim 1, wherein when calculating the correlation calculation curves of the plurality of areas, reliability evaluation of each correlation calculation curve for each of the divided areas is performed, and each of the divided areas having a reliability higher than a predetermined threshold value. An imaging apparatus, wherein the predetermined calculation process is performed only on the correlation calculation curve to obtain the correlation calculation curves of the plurality of areas.

請求項１に記載の撮像装置であって、前記分割エリア毎の相関演算曲線の最大評価値を与える位置が同程度の範囲内となる分割エリア毎の相関演算曲線だけを用いて前記複数エリアの相関演算曲線を求めることを特徴とする撮像装置。 The imaging apparatus according to claim 1, wherein only the correlation calculation curve for each divided area in which the position for giving the maximum evaluation value of the correlation calculation curve for each divided area is within a similar range is used. An imaging apparatus characterized by obtaining a correlation calculation curve.

請求項３に記載の撮像装置であって、各分割エリア毎の相関演算曲線の前記最大評価値を与える位置の多数決をとり、多数となる前記分割エリア毎の相関演算曲線だけを用いて前記複数エリアの相関演算曲線を求めることを特徴とする撮像装置。 The imaging apparatus according to claim 3, wherein a majority decision is made for a position that gives the maximum evaluation value of a correlation calculation curve for each divided area, and the plurality of correlation calculation curves for each of the divided areas are used only. An imaging apparatus characterized by obtaining a correlation calculation curve of an area.

請求項３に記載の撮像装置であって、前記最大評価値を与える位置が同程度の範囲内となる数が複数となり前記複数エリアの相関演算曲線が複数求まるときは、前記最大評価値を与える位置の位相差ズレ量が小さい方の前記複数エリアの相関演算曲線を選択することを特徴とする撮像装置。 The imaging apparatus according to claim 3, wherein the maximum evaluation value is given when there are a plurality of numbers in which the position where the maximum evaluation value is given falls within a similar range and a plurality of correlation calculation curves of the plurality of areas are obtained. An image pickup apparatus, wherein a correlation calculation curve of the plurality of areas having a smaller positional phase difference shift amount is selected.

請求項３に記載の撮像装置であって、前記最大評価値を与える位置が同程度の範囲内となる数が複数となり前記複数エリアの相関演算曲線が複数求まるときは、前記最大評価値を与える位置が前記撮像素子から近い方の前記複数エリアの相関演算曲線を選択することを特徴とする撮像装置。 The imaging apparatus according to claim 3, wherein the maximum evaluation value is given when there are a plurality of numbers in which the position where the maximum evaluation value is given falls within a similar range and a plurality of correlation calculation curves of the plurality of areas are obtained. An imaging apparatus, wherein a correlation calculation curve of the plurality of areas whose positions are closer to the imaging element is selected.

請求項１に記載の撮像装置であって、水平方向の位相差を検出する前記第１の位相差検出画素及び前記第２の位相差検出画素のペア画素の他に垂直方向の位相差を検出する前記第１の位相差検出画素及び前記第２の位相差検出画素のペア画素を前記撮像素子の前記位相差検出エリア内に設け、前記位相差検出エリアをメッシュ状に複数の分割エリアに分割し、各分割エリア毎に、前記水平方向の前記分割エリア毎の相関演算曲線と前記垂直方向の前記分割エリア毎の相関演算曲線とを求め、分割エリア数の２倍の数の前記分割エリア毎の相関演算曲線に基づいて前記複数エリアの相関演算曲線を求める撮像装置。 The imaging device according to claim 1, wherein a phase difference in a vertical direction is detected in addition to a pair pixel of the first phase difference detection pixel and the second phase difference detection pixel that detect a phase difference in a horizontal direction. A pair pixel of the first phase difference detection pixel and the second phase difference detection pixel is provided in the phase difference detection area of the image sensor, and the phase difference detection area is divided into a plurality of divided areas in a mesh shape Then, for each divided area, a correlation calculation curve for each of the divided areas in the horizontal direction and a correlation calculation curve for each of the divided areas in the vertical direction are obtained, and the number of divided areas is twice the number of divided areas. An image pickup apparatus that obtains correlation calculation curves for the plurality of areas based on a correlation calculation curve.

請求項７に記載の撮像装置であって、前記２倍の数の前記分割エリア毎の相関演算曲線のうち、同一分割エリアにおける前記水平方向の分割エリア毎の相関演算曲線と前記垂直方向の分割エリア毎の相関演算曲線とが異なる最大評価値を持つ場合には当該分割エリアの２本の分割エリア毎の相関演算曲線を除外した残りの分割エリア毎の相関演算曲線から前記複数エリアの相関演算曲線を求める撮像装置。 The imaging apparatus according to claim 7, wherein among the doubled number of correlation calculation curves for each divided area, the correlation calculation curve for each horizontal divided area and the vertical division in the same divided area. When the correlation calculation curve for each area has a different maximum evaluation value, the correlation calculation for the plurality of areas is performed from the correlation calculation curves for the remaining divided areas excluding the correlation calculation curves for the two divided areas of the divided area. An imaging device for obtaining a curve.

被写体の画像を撮像する受光面に設けられた位相差検出エリア内に、瞳分割した第１の位相差検出画素及び第２の位相差検出画素で構成されるペア画素が配列形成された撮像素子と、
該撮像素子の前段に置かれ、前記被写体の合焦した光学像を前記受光面に結像させるフォーカスレンズと、
前記第１の位相差検出画素の検出情報と前記第２の位相差検出画素の検出情報との位相差を求め、該位相差に基づき前記フォーカスレンズを前記合焦する位置に制御する制御手段とを備える撮像装置の合焦位置検出方法であって、
前記位相差の検知方向に対して直角方向に前記位相差検出エリアを複数の分割エリアに分割し、
前記分割エリア毎に、当該分割エリア内の前記直角方向に一列に並ぶ複数の前記第１の位相差検出画素の出力信号を、該分割エリア内の前記位相差を検出する方向に並ぶ複数の前記第１の位相差検出画素毎に加算すると共に、前記直角方向に一列に並ぶ複数の前記第２の位相差検出画素の出力信号を、該分割エリア内の前記位相差を検出する方向に並ぶ複数の前記第２の位相差検出画素毎に加算し、
前記分割エリア毎に、前記第１の位相差検出画素の前記加算した信号と前記第２の位相差検出画素の前記加算した信号との相関関係を演算して分割エリア毎の相関演算曲線を算出し、
前記分割エリア毎に算出された前記分割エリア毎の相関演算曲線のうち任意複数個の前記相関演算曲線間に所定演算処理を施して複数エリアの相関演算曲線を求め、該複数エリアの相関演算曲線から前記フォーカスレンズを前記合焦位置に制御する位相差を求める
ことを特徴とする撮像装置の合焦位置検出方法。 An imaging element in which a pair of pixels composed of a first phase difference detection pixel and a second phase difference detection pixel divided into pupils are arrayed in a phase difference detection area provided on a light receiving surface for picking up an image of a subject. When,
A focus lens that is placed in front of the image sensor and forms a focused optical image of the subject on the light receiving surface;
Control means for obtaining a phase difference between detection information of the first phase difference detection pixel and detection information of the second phase difference detection pixel, and controlling the focus lens to the in-focus position based on the phase difference; An in-focus position detection method for an imaging apparatus comprising:
Dividing the phase difference detection area into a plurality of divided areas in a direction perpendicular to the phase difference detection direction;
For each of the divided areas, the output signals of the plurality of first phase difference detection pixels arranged in a line in the perpendicular direction in the divided area are output in the direction in which the phase difference in the divided area is detected. A plurality of first phase difference detection pixels are added and a plurality of second phase difference detection pixel output signals arranged in a line in the perpendicular direction are arranged in a direction in which the phase difference in the divided area is detected. For each of the second phase difference detection pixels,
For each divided area, a correlation calculation curve for each divided area is calculated by calculating a correlation between the added signal of the first phase difference detection pixel and the added signal of the second phase difference detection pixel. And
A correlation calculation curve for a plurality of areas is obtained by performing a predetermined calculation process between the plurality of correlation calculation curves among the correlation calculation curves for each of the divided areas calculated for each of the divided areas. A phase difference for controlling the focus lens to the in-focus position is obtained from the focus position detecting method for the imaging apparatus.

請求項９に記載の撮像装置の合焦位置検出方法であって、前記複数エリアの相関演算曲線を算出するとき前記分割エリア毎の各相関演算曲線の信頼性評価を行い、信頼性が所定閾値より高い前記分割エリア毎の相関演算曲線に対してだけ前記所定演算処理を施して前記複数エリアの相関演算曲線を求めることを特徴とする撮像装置の合焦位置検出方法。 The in-focus position detection method for an imaging apparatus according to claim 9, wherein when calculating the correlation calculation curves of the plurality of areas, reliability evaluation of each correlation calculation curve for each divided area is performed, and the reliability is a predetermined threshold value. An in-focus position detection method for an imaging apparatus, wherein the predetermined calculation process is performed only on a higher correlation calculation curve for each divided area to obtain correlation calculation curves for the plurality of areas.

請求項９に記載の撮像装置の合焦位置検出方法であって、前記分割エリア毎の相関演算曲線の最大評価値を与える位置が同程度の範囲内となる分割エリア毎の相関演算曲線だけを用いて前記複数エリアの相関演算曲線を求めることを特徴とする撮像装置の合焦位置検出方法。 The in-focus position detection method for an imaging apparatus according to claim 9, wherein only the correlation calculation curve for each divided area in which the position for giving the maximum evaluation value of the correlation calculation curve for each divided area is within the same range. An in-focus position detection method for an imaging apparatus, characterized in that correlation calculation curves for the plurality of areas are used.

請求項１１に記載の撮像装置の合焦位置検出方法であって、各分割エリア毎の相関演算曲線の前記最大評価値を与える位置の多数決をとり、多数となる前記分割エリア毎の相関演算曲線だけを用いて前記複数エリアの相関演算曲線を求めることを特徴とする撮像装置の合焦位置検出方法。 The in-focus position detection method for an imaging apparatus according to claim 11, wherein a majority decision is made for a position that gives the maximum evaluation value of a correlation calculation curve for each divided area, and a large number of correlation calculation curves for each divided area. A focus position detection method for an imaging apparatus, wherein a correlation calculation curve for the plurality of areas is obtained using only the image.

請求項１１に記載の撮像装置の合焦位置検出方法であって、前記最大評価値を与える位置が同程度の範囲内となる数が複数となり前記複数エリアの相関演算曲線が複数求まるときは、前記最大評価値を与える位置の位相差ズレ量が小さい方の前記複数エリアの相関演算曲線を選択することを特徴とする撮像装置の合焦位置検出方法。 The in-focus position detection method for an image pickup apparatus according to claim 11, wherein when the number of positions where the maximum evaluation value is given falls within a similar range and a plurality of correlation calculation curves of the plurality of areas are obtained, An in-focus position detection method for an imaging apparatus, wherein a correlation calculation curve of the plurality of areas having a smaller phase difference shift amount at a position where the maximum evaluation value is given is selected.

請求項１１に記載の撮像装置の合焦位置検出方法であって、前記最大評価値を与える位置が同程度の範囲内となる数が複数となり前記複数エリアの相関演算曲線が複数求まるときは、前記最大評価値を与える位置が前記撮像素子から近い方の前記複数エリアの相関演算曲線を選択することを特徴とする撮像装置の合焦位置検出方法。 The in-focus position detection method for an image pickup apparatus according to claim 11, wherein when the number of positions where the maximum evaluation value is given falls within a similar range and a plurality of correlation calculation curves of the plurality of areas are obtained, An in-focus position detection method for an image pickup apparatus, comprising: selecting a correlation calculation curve of the plurality of areas closer to a position where the maximum evaluation value is given from the image pickup device.

請求項９に記載の撮像装置の合焦位置検出方法であって、水平方向の位相差を検出する前記第１の位相差検出画素及び前記第２の位相差検出画素のペア画素の他に垂直方向の位相差を検出する前記第１の位相差検出画素及び前記第２の位相差検出画素のペア画素を前記撮像素子の前記位相差検出エリア内に設け、前記位相差検出エリアをメッシュ状に複数の分割エリアに分割し、各分割エリア毎に、前記水平方向の前記分割エリア毎の相関演算曲線と前記垂直方向の前記分割エリア毎の相関演算曲線とを求め、分割エリア数の２倍の数の前記分割エリア毎の相関演算曲線に基づいて前記複数エリアの相関演算曲線を求める撮像装置の合焦位置検出方法。 The in-focus position detection method for an imaging apparatus according to claim 9, wherein the first phase difference detection pixel for detecting a phase difference in the horizontal direction and a pair pixel of the second phase difference detection pixel are vertical. A pair pixel of the first phase difference detection pixel and the second phase difference detection pixel for detecting a phase difference in direction is provided in the phase difference detection area of the image sensor, and the phase difference detection area is formed in a mesh shape. Dividing into a plurality of divided areas, for each divided area, obtain a correlation calculation curve for each of the divided areas in the horizontal direction and a correlation calculation curve for each of the divided areas in the vertical direction, and double the number of divided areas An in-focus position detection method for an imaging apparatus that obtains correlation calculation curves for the plurality of areas based on a number of correlation calculation curves for each of the divided areas.

請求項１５に記載の撮像装置の合焦位置検出方法であって、前記２倍の数の前記分割エリア毎の相関演算曲線のうち、同一分割エリアにおける前記水平方向の分割エリア毎の相関演算曲線と前記垂直方向の分割エリア毎の相関演算曲線とが異なる最大評価値を持つ場合には当該分割エリアの２本の分割エリア毎の相関演算曲線を除外した残りの分割エリア毎の相関演算曲線から前記複数エリアの相関演算曲線を求める撮像装置の合焦位置検出方法。 The in-focus position detection method for an imaging apparatus according to claim 15, wherein the correlation calculation curve for each horizontal divided area in the same divided area among the doubled number of correlation calculation curves for each divided area. And the correlation calculation curve for each divided area in the vertical direction have different maximum evaluation values, the correlation calculation curves for the remaining divided areas excluding the correlation calculation curves for the two divided areas of the divided area are used. An in-focus position detection method of an imaging apparatus for obtaining a correlation calculation curve of the plurality of areas.