JP3271260B2 - Vertical contour compensation circuit - Google Patents
Vertical contour compensation circuitInfo
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- JP3271260B2 JP3271260B2 JP26168389A JP26168389A JP3271260B2 JP 3271260 B2 JP3271260 B2 JP 3271260B2 JP 26168389 A JP26168389 A JP 26168389A JP 26168389 A JP26168389 A JP 26168389A JP 3271260 B2 JP3271260 B2 JP 3271260B2
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- imaging
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、補色フィルタと固体撮像素子とを用いたビ
デオカメラの垂直輪郭補償回路に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical contour compensation circuit of a video camera using a complementary color filter and a solid-state imaging device.
本発明は、補色フィルタと固体撮像素子とを用いたビ
デオカメラの垂直輪郭補償回路において、この固体撮像
素子より得られる1ラインの撮像信号と当該撮像信号に
隣接するラインの撮像信号を加算した信号と、この2つ
のラインの撮像信号を減算して得られた信号に第1の乗
算手段で係数を掛けた第1の垂直高域成分信号を加算す
る第1の加算手段と、この撮像信号と当該撮像信号のn
水平期間前後(n=1,2,3‥‥)のラインの撮像信号に
夫々正負所定の極性を付して加算して得られた信号に、
第2の乗算手段で係数を掛け、当該第2の乗算手段の出
力の第2の垂直高域成分信号をこの第1の加算手段の出
力に加算する第2の加算手段とを有することにより、垂
直方向の空間周波数レスポンスの調整の自由度を高め、
垂直方向の輪郭特性を良好にして画質を改善できる様に
したものである。The present invention relates to a vertical contour compensation circuit of a video camera using a complementary color filter and a solid-state imaging device, a signal obtained by adding an imaging signal of one line obtained from the solid-state imaging device and an imaging signal of a line adjacent to the imaging signal. And first addition means for adding a first vertical high-frequency component signal obtained by multiplying a signal obtained by subtracting the image signals of these two lines by a coefficient by a first multiplication means; N of the imaging signal
To the signals obtained by adding the imaging signals of the lines before and after the horizontal period (n = 1, 2, 3 ‥‥) with predetermined positive and negative polarities, respectively,
A second adding means for multiplying a coefficient by a second multiplying means and adding a second vertical high-frequency component signal output from the second multiplying means to an output from the first adding means, Increase the degree of freedom in adjusting the spatial frequency response in the vertical direction,
The image quality can be improved by improving the contour characteristics in the vertical direction.
ビデオカメラにおいては、受光面に形成された光学像
を或る面積を有する画素単位で分解されることに起因し
てカメラの解像度が低下する現象である所謂アパーチャ
歪みが生じる。このアパーチャ歪みを補正すると共に更
に画質を改善するために、近時は水平方向及び垂直方向
の輪郭補償回路が使用されている。In a video camera, so-called aperture distortion, which is a phenomenon in which the resolution of the camera is reduced due to the decomposition of an optical image formed on the light receiving surface into pixels having a certain area, is generated. In order to correct the aperture distortion and further improve the image quality, recently, horizontal and vertical contour compensation circuits are used.
第3図は所謂市松模様の補色フィルタと単板式で2ラ
イン同時読出しを行なうCCD(Charge Coupled Devic
e)とを用いたビデオカメラの垂直輪郭補償回路を示
し、この第3図において、(1)はCCD、(2)市松模
様の補色フィルタであり、この補色フィルタ(2)には
垂直方向(Y方向)にピッチPで帯状のパターン(3
A),(3B),(3C),‥‥が形成されている。それら
のパターン(3A),(3E),‥‥には夫々水平方向(X
方向)に緑(Gr)とマゼンダ(Mg)とが交互に着色さ
れ、パターン(3B),(3D),(3F),‥‥には夫々水
平方向にシアン(Cy)と黄(Ye)とが交互に着色され、
パターン(3C),(3F),‥‥には夫々水平方向にマゼ
ンダ(Mg)と緑(Gr)とが交互に着色されており、その
補色フィルタ(2)を構成する各単色フィルタに夫々対
応してそのCCD(1)の各画素が形成されている。FIG. 3 shows a so-called checkerboard complementary color filter and a CCD (Charge Coupled Device) which simultaneously reads out two lines in a single-plate system.
3) shows a vertical contour compensating circuit of a video camera using (e). In FIG. 3, (1) is a CCD, (2) a complementary color filter having a checkered pattern, and the complementary color filter (2) has a vertical direction ( A band-like pattern (3
A), (3B), (3C), and ‥‥ are formed. The patterns (3A), (3E), and ‥‥ have the horizontal direction (X
Direction), green (Gr) and magenta (Mg) are alternately colored, and patterns (3B), (3D), (3F), and ‥‥ have cyan (Cy) and yellow (Ye) in the horizontal direction, respectively. Are alternately colored,
Patterns (3C), (3F), and ‥‥ are colored alternately with magenta (Mg) and green (Gr) in the horizontal direction, respectively, and correspond to each monochromatic filter that composes its complementary color filter (2). Then, each pixel of the CCD (1) is formed.
そして、2ライン同時読出しの場合には、奇数フィー
ルド期間には例えばパターン(3A)及び(3B)に対応す
るCCD(1)の2ラインの画素(4A)の信号(撮像信
号)が同時に読出され、続いて2ラインの画素(4B),
(4C),‥‥の信号が順次同時に読出される。一方、偶
数フィールド期間にはパターン(3B)及び(3C)に対応
するCCD(1)の2ラインの画素(5A)の信号が同時に
読出され、続いて2ラインの画素(5B),(5C),‥‥
の信号が順次同時に読出される。これら同時に読出され
る2ラインの画素の撮像信号I(m)及びI(m+1)
(m=1,2,3,‥‥)が夫々接続端子(6)及び(7)を
介して加算回路(8)及び減算回路(9)に供給され、
加算回路(8)からは次式で表され輪郭補正の基礎とな
る信号aが加算回路(10)の一方の入力端子に供給され
る。In the case of simultaneous reading of two lines, signals (image signals) of pixels (4A) of two lines of the CCD (1) corresponding to, for example, patterns (3A) and (3B) are simultaneously read during the odd field period. , Followed by two lines of pixels (4B),
(4C), The signals of ‥‥ are sequentially and simultaneously read. On the other hand, during the even field period, the signals of the pixels (5A) of two lines of the CCD (1) corresponding to the patterns (3B) and (3C) are simultaneously read out, and subsequently the pixels (5B) and (5C) of two lines , ‥‥
Are sequentially and simultaneously read out. The imaging signals I (m) and I (m + 1) of the two lines of pixels that are simultaneously read out.
(M = 1, 2, 3,...) Are supplied to the addition circuit (8) and the subtraction circuit (9) via the connection terminals (6) and (7), respectively.
From the adder circuit (8), a signal a represented by the following equation and serving as a basis for contour correction is supplied to one input terminal of the adder circuit (10).
a=I(m)+I(m+1) ‥‥(1) また、(11)は入力信号と出力信号との関係が第4図
の如くなりノイズを遮断する役割を果たすコアリング回
路、(12)は入力信号に係数Kを乗ずる乗算回路を示
し、減算回路(9)の出力信号がコアリング回路(11)
及び乗算回路(12)を介して次式で表わされる垂直高域
成分信号bに変換され、信号bが加算回路(10)の他方
の入力端子に供給される。a = I (m) + I (m + 1) (1) Further, (11) is a coring circuit which plays a role of blocking noise by making the relationship between the input signal and the output signal as shown in FIG. 4, (12) Denotes a multiplication circuit for multiplying the input signal by a coefficient K, and the output signal of the subtraction circuit (9) is a coring circuit (11)
Then, the signal is converted into a vertical high-frequency component signal b represented by the following equation via a multiplier circuit (12), and the signal b is supplied to the other input terminal of the adder circuit (10).
b≒K(I(m)−I(m+1)) ‥‥(2) そして、加算回路(10)にてその基礎となる信号aに
その垂直高域成分信号bが加算されて補正後のm番目の
水平走査信号J(m)が得られ、この信号J(m)は出
力端子(13)を介して図示省略した映像信号処理回路に
供給される。尚、第3図例で得られる信号a,b及びJ
(m)は夫々輝度信号であり、色信号については別の回
路で処理される。b ≒ K (I (m) −I (m + 1)) ‥‥ (2) Then, the vertical high frequency component signal b is added to the base signal a by the addition circuit (10), and m is corrected. A second horizontal scanning signal J (m) is obtained, and this signal J (m) is supplied to a video signal processing circuit (not shown) via an output terminal (13). The signals a, b and J obtained in the example of FIG.
(M) is a luminance signal, and a chrominance signal is processed by another circuit.
第3図例の垂直方向の空間周波数がfの成分について
のレスポンスについて検討するに、m番目のラインの撮
像信号I(m)の垂直方向(Y方向)の平均位置をyと
すると、撮像信号I(m)及びI(m+1)は直流分を
無視すると夫々定数A及びαを用いて次のように表わす
ことができる。In order to examine the response of the component having the spatial frequency f in the vertical direction in the example of FIG. 3, assuming that the average position in the vertical direction (Y direction) of the imaging signal I (m) of the m-th line is y, I (m) and I (m + 1) can be expressed as follows using constants A and α, respectively, ignoring the DC component.
I(m)=Asin(2πfy+α) ‥‥(3) I(m+1)=Asin(2πf(y+P)+α) ‥‥(4) 従って、信号a及びbは夫々次のように表わすことが
できる。I (m) = Asin (2πfy + α) ‥‥ (3) I (m + 1) = Asin (2πf (y + P) + α) ‥‥ (4) Accordingly, the signals a and b can be expressed as follows, respectively.
a=I(m)+I(m+1) =Asin(2πf(y+P/2)+α) ・cos(πfP) ‥‥(5) b≒K(I(m)−I(m+1)) =−KAcos(2πf(y+P/2)+α) ・sin(πfP) ‥‥(6) この式(5)において、信号aの振幅はcos(πfP)
の絶対値によって制限され、cos(πfP)の絶対値はf
≪1/Pのときに略1となりf=1/(2P)のときに0とな
る。従って、信号aの空間周波数レスポンスは第5図A
に示す如きローパスフィルタ回路特性となる。a = I (m) + I (m + 1) = Asin (2πf (y + P / 2) + α) cos (πfP)) (5) b ≒ K (I (m) −I (m + 1)) = − KAcos (2πf (Y + P / 2) + α) sin (πfP) P (6) In this equation (5), the amplitude of the signal a is cos (πfP)
And the absolute value of cos (πfP) is f
It becomes approximately 1 when と き に 1 / P, and becomes 0 when f = 1 / (2P). Therefore, the spatial frequency response of signal a is shown in FIG.
The low-pass filter circuit characteristics shown in FIG.
一方、この式(6)において、信号bの振幅はsin
(πfP)の絶対値によって制限され、sin(πfP)の絶
対値はf≪1/Pのときに略0となりf=1/(2P)のとき
に1となる。従って、信号bの空間周波数レスポンスは
第5図Bに示す如きハイパスフィルタ回路特性となる。On the other hand, in the equation (6), the amplitude of the signal b is sin
It is limited by the absolute value of (πfP), and the absolute value of sin (πfP) becomes substantially 0 when f≪1 / P, and becomes 1 when f = 1 / (2P). Therefore, the spatial frequency response of the signal b has a high-pass filter circuit characteristic as shown in FIG. 5B.
そして、信号aに信号bを加算して得られる水平走査
信号J(m)の空間周波数レスポンスは、第5図Cに示
す如く、ほぼ第5図Aの特性と第5図Bの特性とを加算
した特性となり、空間周波数の高い領域にピーク(14)
がある。そして、第3図の乗算回路(12)における係数
Kの値を種々に設定することにより、水平走査信号J
(m)の空間周波数レスポンスの特性はある程度変更す
ることができる。尚、第5図では空間周波数レスポンス
を表わす曲線の横軸の単位は〔TV本〕であり、その横軸
の最大値は略500〔TV本〕である。また、第5図の特性
は振幅特性のみであり信号a及び信号bの位相特性は夫
々異なっているため、第5図Cの曲線は必ずしも第5図
Aの曲線と第5図Bの曲線との加算結果にはならない。Then, as shown in FIG. 5C, the spatial frequency response of the horizontal scanning signal J (m) obtained by adding the signal b to the signal a substantially matches the characteristic shown in FIG. 5A and the characteristic shown in FIG. 5B. Adds the characteristics and peaks in the region with high spatial frequency (14)
There is. Then, by setting the value of the coefficient K in the multiplication circuit (12) of FIG.
The characteristics of the spatial frequency response of (m) can be changed to some extent. In FIG. 5, the unit of the horizontal axis of the curve representing the spatial frequency response is [TV lines], and the maximum value of the horizontal axis is approximately 500 [TV lines]. Also, since the characteristic in FIG. 5 is only the amplitude characteristic and the phase characteristics of the signal a and the signal b are different from each other, the curve in FIG. 5C is not necessarily the curve in FIG. 5A and the curve in FIG. Does not result in the addition of
上述のように従来の垂直輪郭補償回路においては、係
数Kの値を調整して信号aと信号bとの混合比を変える
ことによりある程度空間周波数レスポンスの特性を変え
ることができる。しかしながら、その混合の元になる信
号a及び信号bは夫々単純なローパス特性およびハイパ
ス特性であるため、その混合比を変えて得られる特性の
範囲には制限があり、所望の空間周波数レスポンス特性
を得ることができない不都合があった。そのため、最終
的に得られる画像の垂直方向の輪郭の鮮明度等に影響さ
れる画質についても必ずしも満足できるものが得られて
いなかった。As described above, in the conventional vertical contour compensation circuit, the characteristics of the spatial frequency response can be changed to some extent by adjusting the value of the coefficient K and changing the mixing ratio of the signal a and the signal b. However, since the signal a and the signal b that cause the mixing have simple low-pass characteristics and high-pass characteristics, respectively, the range of characteristics obtained by changing the mixing ratio is limited. There were inconveniences that could not be obtained. For this reason, a satisfactory image quality which is affected by the sharpness of the vertical contour of the finally obtained image has not always been obtained.
本発明は斯かる点に鑑み、ビデオカメラの垂直輪郭補
償回路において、得られる空間周波数のレスポンス特性
の調整の自由度を高めてより高画質が得られるようにす
ることを目的とする。In view of the above, it is an object of the present invention to provide a vertical contour compensation circuit of a video camera with a higher degree of freedom in adjusting a response characteristic of an obtained spatial frequency so as to obtain higher image quality.
本発明垂直輪郭補償回路は例えば第1図に示す如く、
補色フィルタ(2)と固体撮像素子(1)とを用いたビ
デオカメラの垂直輪郭補償回路において、この固体撮像
素子(1)より得られる1ラインの撮像信号I(m+
1)と当該撮像信号I(m+1)に隣接するラインの撮
像信号I(m)を加算した信号aと、この2つのライン
の撮像信号I(m),I(m+1)を減算して得られた信
号I(m)−I(m+1)に第1の乗算手段(12)で係
数K1を掛けた第1の垂直高域成分信号bを加算する第1
の加算手段(10)と、この撮像信号I(m+1)と当該
撮像信号I(m+1)のn水平期間前後(n=1,2,3‥
‥)のラインの撮像信号I(m),I(m+2)に夫々正
負所定の極性を付して加算して得られた信号例えば(I
(m)+I(m+1)+I(m+2))に、第2の乗算
手段(20)で係数K2を掛け、当該第2の乗算手段(20)
の出力の第2の垂直高域成分信号をこの第1の加算手段
(10)の出力に加算する第2の加算手段(22)とを有す
るものである。The vertical contour compensation circuit of the present invention is, for example, as shown in FIG.
In a vertical contour compensation circuit of a video camera using a complementary color filter (2) and a solid-state imaging device (1), a one-line imaging signal I (m +
1) is obtained by subtracting the signal a obtained by adding the image signal I (m) of the line adjacent to the image signal I (m + 1) and the image signals I (m) and I (m + 1) of the two lines. the signal I (m) -I (m + 1) to the first adding the first vertical high-frequency component signal b multiplied by the coefficient K 1 in the first multiplier means (12)
Adding means (10), the image signal I (m + 1), and before and after n horizontal periods of the image signal I (m + 1) (n = 1, 2, 3 ‥).
‥) A signal obtained by adding the imaging signals I (m) and I (m + 2) of the line with predetermined positive and negative polarities, for example, (I)
(M) + I (m + 1) + I (m + 2)) is multiplied by a coefficient K2 by the second multiplication means (20), and the second multiplication means (20)
And a second adding means (22) for adding the output of the second vertical high frequency component signal to the output of the first adding means (10).
斯かる本発明によれば、1ラインの撮像信号に対して
n水平期間前後のラインの撮像信号を夫々加減算して係
数を掛けることにより、例えばバンドパス特性など様々
な空間周波数レスポンスの特性を有する垂直高域成分信
号が得られる。従って、それら係数を調整してその垂直
高域成分信号をその所定のラインの撮像信号に加算する
ことにより、得られる空間周波数のレスポンス特性の周
波数の自由度が高まりより高画質が得られる。According to the present invention, the image signal of one line is added to and subtracted from the image signal of the line before and after the n horizontal periods, and is multiplied by a coefficient, thereby having various spatial frequency response characteristics such as bandpass characteristics. A vertical high frequency component signal is obtained. Therefore, by adjusting the coefficients and adding the vertical high-frequency component signal to the imaging signal of the predetermined line, the degree of freedom of the frequency response characteristic of the obtained spatial frequency is increased, and higher image quality is obtained.
以下、本発明垂直輪郭補償回路の一実施例につき第1
図及び第2図を参照して説明しよう。本例は単板式で2
ライン同時読出し方式のCCDを用いるビデオカメラに本
発明を適用したものであり、この第1図において第3図
に対応する部分には同一符号を付してその詳細説明は省
略すると共に、第3図例のコアリング回路(11)に対応
する回路は図示を省略する。また、本例でもCCDから読
出された撮像信号は輝度信号として扱う。Hereinafter, a first embodiment of the vertical contour compensation circuit according to the present invention will be described.
This will be described with reference to FIG. 2 and FIG. This example is a single plate type 2
In this embodiment, the present invention is applied to a video camera using a CCD of a line simultaneous readout system. In FIG. 1, portions corresponding to those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. A circuit corresponding to the coring circuit (11) in the figure is not shown. Also in this example, the imaging signal read from the CCD is treated as a luminance signal.
第1図は本例の垂直輪郭補償回路を示し、この第1図
において、CCD(1)から同時に読出された2ライン
((m+2)番目のライン及び(m+3)番目のライ
ン)の撮像信号I(m+2)及びI(m+3)を夫々接
続端子(6)及び(7)を介してラインメモリ(L・
M)(15)及び(16)に供給し、ラインメモリ(16)か
ら読出した信号をラインメモリ(L・M)(17)に供給
する。これらラインメモリ(17),(15)及び(16)か
ら読出される信号が夫々撮像信号I(m−1),I(m)
及びI(m+1)に相当する。また、2ライン同時読出
しであるから、撮像信号I(m+1)を高域補償の基準
にすると、信号I(m−1)は1H(1Hは1水平期間を意
味する)前の撮像信号であり、信号I(m+2)及びI
(m+3)は夫々1H後の撮像信号である。FIG. 1 shows a vertical contour compensation circuit of the present embodiment. In FIG. 1, an image pickup signal I of two lines ((m + 2) th line and (m + 3) th line) simultaneously read from CCD (1). (M + 2) and I (m + 3) are connected to the line memory (L.multidot.L) via the connection terminals (6) and (7), respectively.
M) (15) and (16), and a signal read from the line memory (16) is supplied to the line memory (LM) (17). The signals read from these line memories (17), (15) and (16) are image signals I (m-1) and I (m), respectively.
And I (m + 1). Also, since two lines are read simultaneously, if the imaging signal I (m + 1) is used as a reference for high-frequency compensation, the signal I (m-1) is an imaging signal 1H (1H means one horizontal period) before. , Signals I (m + 2) and I
(M + 3) are image signals after 1H, respectively.
本例においても、加算回路(8)にて信号I(m)に
信号I(m+1)を加算して得られた信号aを加算回路
(10)の一方の入力端子に供給し、減算回路(9)にて
信号I(m)から信号I(m+1)を減算して得られた
信号に乗算回路(12)にて係数K1を乗じて得られる垂直
高域成分信号bを加算回路(10)の他方の入力端子に供
給する。また、(18)及び(19)は夫々3入力の加減算
回路を示し、入力信号をA,B,Cとすると、これら加減算
回路(18)及び(19)は夫々それら入力信号の2種類を
組合せて成る信号(例えばA+B,A−B)や3種類を組
合せて成る信号(例えばA+B+C,A−B+C)の内で
所望の空間周波数のレスポンス特性を有する信号を生成
する。Also in this example, a signal a obtained by adding the signal I (m + 1) to the signal I (m) in the addition circuit (8) is supplied to one input terminal of the addition circuit (10), and the subtraction circuit ( signal I (m) from the signal I (m + 1) obtained by subtracting the signal obtained by the multiplication circuit (12) adding the vertical high-frequency component signal b obtained by multiplying the coefficient K 1 at circuit at 9) (10 ) To the other input terminal. (18) and (19) denote three-input addition / subtraction circuits, respectively. If the input signals are A, B and C, these addition / subtraction circuits (18) and (19) combine two types of these input signals, respectively. A signal having a desired spatial frequency response characteristic is generated from among the signals (for example, A + B, AB) and the signals (for example, A + B + C, AB-C) that are obtained by combining the three types.
そして、加減算回路(18)は信号I(m),I(m+
1)及びI(m+2)を加減算して得られた信号を乗算
回路(20)に供給し、加減算回路(19)は信号I(m−
1),I(m+1)及びI(m+3)を加減算して得られ
た信号を乗算回路(21)に供給する。これら乗算回路
(20)及び(21)は夫々入力信号に係数K2及びK3を乗じ
て垂直高域成分信号c及びdを生成する。Then, the addition / subtraction circuit (18) outputs the signals I (m) and I (m +
1) and a signal obtained by adding and subtracting I (m + 2) are supplied to a multiplying circuit (20), and an adding / subtracting circuit (19) provides a signal I (m−2).
1) A signal obtained by adding and subtracting I (m + 1) and I (m + 3) is supplied to a multiplier circuit (21). These multiplier circuits (20) and (21) produces a vertical high frequency component signal c and d is multiplied by a coefficient K 2 and K 3 respectively input signal.
そして、加算回路(10)にて信号aに信号bを加算
し、加算回路(22)にて加算回路(10)の出力信号に信
号cを加算し、加算回路(23)にて加算回路(22)の出
力信号に信号dを加算することにより、垂直方向の輪郭
が補正されたm番目の水平走査信号J(m)を生成し、
この信号J(m)を出力端子(13)に供給する如くな
す。尚、更に信号I(m−2),I(m−3),‥‥及び
信号I(m+4),I(m+5),‥‥をも用いてより高
次の垂直高域成分信号を生成し、このより高次の信号を
その信号J(m)に加算する如くなしてもよい。The addition circuit (10) adds the signal a to the signal a, the addition circuit (22) adds the signal c to the output signal of the addition circuit (10), and the addition circuit (23) By adding the signal d to the output signal of 22), an m-th horizontal scanning signal J (m) whose vertical contour has been corrected is generated,
This signal J (m) is supplied to the output terminal (13). Further, a higher-order vertical high-frequency component signal is generated using the signals I (m-2), I (m-3), ‥‥ and the signals I (m + 4), I (m + 5), ‥‥. , The higher-order signal may be added to the signal J (m).
本例の信号a及びbの空間周波数の振幅成分のレスポ
ンス特性は、既に式(5)及び(6)を用いて説明した
如く、夫々ローパス特性(第2図A)及びハイパス特性
(第2図B)になる。また、信号dの垂直方向の空間周
波数fにおけるレスポンス特性について検討するに、信
号dは例えば次式で表現されるものとする。The response characteristics of the amplitude components of the spatial frequencies of the signals a and b in this example are, as already described with reference to equations (5) and (6), the low-pass characteristics (FIG. 2A) and the high-pass characteristics (FIG. 2), respectively. B). In order to study the response characteristics of the signal d at the spatial frequency f in the vertical direction, the signal d is assumed to be expressed by the following equation, for example.
d=K3(I(m−1)−I(m+3)) ‥‥(7) この場合、信号I(m)が式(3)で定義されるもの
とすると、補色フィルタ(2)のパターン(3A),(3
B),‥‥の垂直方向(Y方向)のピッチはPであるた
め式(3)は次のように変形できる。d = K 3 (I (m−1) −I (m + 3)) (7) In this case, assuming that the signal I (m) is defined by Expression (3), the pattern of the complementary color filter (2) (3A), (3
Since the pitch in the vertical direction (Y direction) of B) and ‥‥ is P, equation (3) can be modified as follows.
d/K3=Asin(2πf(y−P)+α) −Asin(2πf(y+3P)+α) =−Acos(2πf(y+P)+α) ・sin(4πfP) ‥‥(8) 従って、信号dの振幅はsin(4πfP)の絶対値によ
って制限され、sin(4πfP)の絶対値はf=0,f=1/
(4P),f=1/(2P),‥‥のときに夫々0となり、f=
1/(8P),f=3/(8P),‥‥のときに夫々1となる。即
ち、信号dの空間周波数のレスポンス特性は第2図Dに
示す如く一種のバンドパスフィルタ回路又はくし型フィ
ルタ回路の特性になる。同様に、加減算回路(18)の加
減算の方法を選択することにより信号cの空間周波数の
レスポンス特性は例えば第2図Cに示すような特性に設
定することができる。従って、信号aに信号b,c,dを順
次加算して得られるm番目の水平走査信号J(m)の垂
直方向の空間周波数のレスポンス特性は、ほぼ第2図E
に示す如く2つのピーク(24)及び(25)を有する特性
となる。そして、この信号J(m)のレスポンス特性は
加減算回路(18),(19)における加減算の方法を種々
に加えることにより、また係数K1〜K3の値を種々に変え
ることにより、そのピーク(24)及び(25)の位置を変
更できると共に、そのピークの数を例えば3個以上にす
ることもできる。d / K 3 = Asin (2πf (y−P) + α) −Asin (2πf (y + 3P) + α) = − Acos (2πf (y + P) + α) · sin (4πfP) ‥‥ (8) Therefore, the amplitude of the signal d Is limited by the absolute value of sin (4πfP), and the absolute value of sin (4πfP) is f = 0, f = 1 /
(4P), f = 1 / (2P), 0 when 0, and f =
1 / (8P), f = 3 / (8P), 1 when ‥‥. That is, the response characteristic of the spatial frequency of the signal d becomes the characteristic of a kind of band-pass filter circuit or comb filter circuit as shown in FIG. 2D. Similarly, by selecting an addition / subtraction method of the addition / subtraction circuit (18), the response characteristic of the spatial frequency of the signal c can be set to a characteristic as shown in FIG. 2C, for example. Accordingly, the response characteristic of the spatial frequency in the vertical direction of the m-th horizontal scanning signal J (m) obtained by sequentially adding the signals b, c, and d to the signal a is substantially equal to that of FIG.
As shown in FIG. 7, the characteristic has two peaks (24) and (25). Then, the response characteristic of the signal J (m) is subtraction circuit (18), by adding the various addition and subtraction method in (19), also by changing the value of the coefficient K 1 ~K 3 variously its peak The positions of (24) and (25) can be changed, and the number of peaks can be set to, for example, three or more.
上述のように、本例によれば基本となるラインの撮像
信号I(m+1)に対して±1ライン及び±2ライン前
後の撮像信号を加減算しているので、単なるローパス特
性又はハイパス特性のみならず、バンドパス特性やくし
型特性等の様々なレスポンス特性を有する垂直高域成分
信号を得ることができる。また、係数K1〜K3の値を調整
することにより信号a,b,c,dの混合比を変えることがで
きる。従って、最終的に得られる水平走査信号J(m)
の垂直方向の空間周波数のレスポンス特性の調整の自由
度が大きくなると共に、所望のレスポンス特性を得るこ
とができる利益がある。As described above, according to this example, the imaging signals of ± 1 line and ± 2 lines are added to and subtracted from the imaging signal I (m + 1) of the basic line. Instead, it is possible to obtain a vertical high-frequency component signal having various response characteristics such as bandpass characteristics and comb characteristics. Further, by adjusting the values of the coefficients K 1 to K 3 , the mixing ratio of the signals a, b, c, and d can be changed. Therefore, the finally obtained horizontal scanning signal J (m)
The degree of freedom in adjusting the response characteristics of the spatial frequency in the vertical direction is increased, and a desired response characteristic can be obtained.
そして、それら信号a,b,c,dの混合比等を調整するこ
とにより得られる画像の垂直方向の所定の空間周波数成
分の輪郭を強調するなどして、より画質を改善すること
ができる。By adjusting the mixture ratio of the signals a, b, c, d and the like, the outline of a predetermined spatial frequency component in the vertical direction of the obtained image can be enhanced, and the image quality can be further improved.
尚、上述実施例は2ライン同時読出しのCCDを用いた
ビデオカメラに本発明を適用したものであるが、例えば
通常の方式である2ラインの信号が混合された形で読出
されるCCDを用いたビデオカメラやCCDの代わりにMOS型
撮像素子等を用いたビデオカメラにも本発明は適用され
る。In the above-described embodiment, the present invention is applied to a video camera using a CCD of two-line simultaneous reading. For example, a CCD that is read in a form in which two-line signals are mixed in a normal system is used. The present invention is also applicable to a video camera using a MOS type imaging device or the like instead of a conventional video camera or CCD.
このように本発明は上述実施例に限定されず、本発明
の要旨を逸脱しない範囲で種々の構成を採り得ることは
勿論である。As described above, the present invention is not limited to the above-described embodiment, and may adopt various configurations without departing from the spirit of the present invention.
本発明によれば、n水平期間前後のラインの撮像信号
を夫々加減算することによりバンドパス特性やくし型特
性等の様々の特性を有する垂直高域成分信号が得られる
ので、垂直方向の空間周波数のレスポンス特性の調整の
自由度が大きくなる。従って、垂直方向の輪郭の鮮明度
等が所望の程度に設定でき、全体として画質を改善でき
る実用上の利益がある。According to the present invention, a vertical high frequency component signal having various characteristics such as bandpass characteristics and comb characteristics can be obtained by adding and subtracting image signals of lines before and after n horizontal periods, respectively. The degree of freedom in adjusting the response characteristics increases. Therefore, there is a practical advantage that the sharpness of the contour in the vertical direction can be set to a desired degree and the image quality can be improved as a whole.
第1図は本発明による垂直輪郭補償回路の一実施例を示
す構成図、第2図は第1図例の各部信号の垂直方向の空
間周波数のレスポンス特性を示す線図、第3図は従来の
垂直輪郭補償回路の例を示す構成図、第4図は第3図例
のコアリング回路(11)の動作の説明に供する線図、第
5図は第3図例の各部信号の垂直方向の空間周波数のレ
スポンス特性を示す線図である。 (1)はCCD、(2)は補色フィルタ、(8),(1
0),(22)及び(23)は夫々加算回路、(9)は減算
回路、(12),(20)及び(21)は夫々乗算回路、(1
5),(16)及び(17)は夫々ラインメモリ、(18)及
び(19)は夫々加減算回路である。FIG. 1 is a block diagram showing an embodiment of a vertical contour compensation circuit according to the present invention, FIG. 2 is a diagram showing a response characteristic of a spatial frequency in the vertical direction of each signal in the example of FIG. 1, and FIG. FIG. 4 is a diagram for explaining the operation of the coring circuit (11) of FIG. 3, and FIG. 5 is a vertical direction of each signal of FIG. FIG. 3 is a diagram showing response characteristics of spatial frequencies of FIG. (1) is a CCD, (2) is a complementary color filter, (8), (1)
(0), (22) and (23) are addition circuits, (9) is a subtraction circuit, (12), (20) and (21) are multiplication circuits, (1)
5), (16) and (17) are line memories, respectively, and (18) and (19) are addition and subtraction circuits, respectively.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭63−62493(JP,A) 特開 平2−141089(JP,A) (58)調査した分野(Int.Cl.7,DB名) H04N 9/04 - 9/11 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-62493 (JP, A) JP-A-2-141089 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) H04N 9/04-9/11
Claims (1)
デオカメラの垂直輪郭補償回路において、 上記固体撮像素子より得られる1ラインの撮像信号と当
該撮像信号に隣接するラインの撮像信号を加算した信号
と、上記2つのラインの撮像信号を減算して得られた信
号に第1の乗算手段で係数を掛けた第1の垂直高域成分
信号を加算する第1の加算手段と、 上記撮像信号と当該撮像信号のn水平期間前後(n=1,
2,3‥‥)のラインの撮像信号に夫々正負所定の極性を
付して加算して得られた信号に、第2の乗算手段で係数
を掛け、当該第2の乗算手段の出力の第2の垂直高域成
分信号を上記第1の加算手段の出力に加算する第2の加
算手段と を有することを特徴とする垂直輪郭補償回路。In a vertical contour compensation circuit of a video camera using a complementary color filter and a solid-state imaging device, an imaging signal of one line obtained from the solid-state imaging device and an imaging signal of a line adjacent to the imaging signal are added. First addition means for adding a signal and a first vertical high-frequency component signal obtained by multiplying a signal obtained by subtracting the two lines of imaging signals with a coefficient by a first multiplication means; And before and after n horizontal periods of the imaging signal (n = 1,
A signal obtained by adding the image pickup signals of the lines (2, 3 ‥‥) with predetermined positive and negative polarities and adding them is multiplied by a coefficient by a second multiplying means, and a second signal of the output of the second multiplying means is multiplied. And a second adding means for adding the two vertical high frequency component signals to the output of the first adding means.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP26168389A JP3271260B2 (en) | 1989-10-06 | 1989-10-06 | Vertical contour compensation circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP26168389A JP3271260B2 (en) | 1989-10-06 | 1989-10-06 | Vertical contour compensation circuit |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH03123275A JPH03123275A (en) | 1991-05-27 |
JP3271260B2 true JP3271260B2 (en) | 2002-04-02 |
Family
ID=17365276
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP26168389A Expired - Lifetime JP3271260B2 (en) | 1989-10-06 | 1989-10-06 | Vertical contour compensation circuit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3271260B2 (en) |
-
1989
- 1989-10-06 JP JP26168389A patent/JP3271260B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPH03123275A (en) | 1991-05-27 |
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