JPS59218410A - Automatic focusing method - Google Patents

Abstract

PURPOSE:To make automatic focusing possible with a simple constitution by deriving a point where the difference between an image subjected to average value processing or smoothing and an image which is not subjected to processings at all is maximum. CONSTITUTION:A video signal 9 from a camera 6 is allowed to pass an average value processing or smoothing means 7, and a video signal 10 whose high frequency components are removed and the original video signal 9 from the camera 6 are compared with each other in a comparator 8 to obtain the difference, and an output 11 is derived by an addition with respect to the whole of a picture or a designated area, and the dispersion of this difference is obtained while moving an object or a focusing lens and the camera 6 relatively in the direction of the optical axis, and the camera is adjusted to the in-focus position where the dispersion is maximum. These functions are constituted of a video RAM device for the purpose of facilitating measurement of dimensions and recognition of the position of the object after automatic focusing. That is, the image from a camera 12 is inputted to an image memory 13. The image memory can be accessed from a computer 14, and said functions are realized with software.

Description

【発明の詳細な説明】 〔発明の利用分野〕 本発明は、自動焦点顕微鏡等の自動焦点合せ方法に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an automatic focusing method for an automatic focusing microscope or the like.

〔発明の背景〕[Background of the invention]

従来の自動焦点合せは、特公昭３９−２４１５２号に示
すように例えば第１図に示すように合焦点面５の前後に
等間隔で置いた光電素子２，６でレンズ１を介して撮像
して得られる信号の出力が等しくなることを利用してピ
ント面前後でボケの程度が等しい点を検出し、その中間
を合焦点とするものがある。また、特開昭５２−１５０
０２４号に開示されているように光導電素子が合焦時に
抵抗が極値を示すことを利用したものが知られ、またポ
ラロイドカメラに見られる放射した超音波が被写体に当
って反射してくる時間を測定するものが考案されている
。しかし、産業応用面では通常自動焦点合せを行った後
に、対象物の寸法測定や位置認識を行うことを要求され
ることが多い。そのため今挙げた自動焦点合せの方法で
は、焦点合せとは別に寸法測定や位置認識を行う機構が
必要になり、規模、価格の点で問題があった。In conventional automatic focusing, as shown in Japanese Patent Publication No. 39-24152, for example, as shown in FIG. There is a method that uses the fact that the output of the signal obtained by the two methods is equal to each other to detect a point where the degree of blur is equal before and after the focal plane, and sets the point in the middle as the focal point. Also, JP-A-52-150
As disclosed in No. 024, there is a known device that takes advantage of the fact that the resistance of a photoconductive element shows an extreme value when it is focused, and the ultrasonic waves emitted from a Polaroid camera hit the subject and are reflected. Something has been devised to measure time. However, in industrial applications, it is often required to measure the dimensions and recognize the position of the object after automatic focusing. Therefore, the automatic focusing method just mentioned requires a mechanism that measures dimensions and recognizes the position in addition to focusing, which poses problems in terms of scale and cost.

〔発明の目的〕[Purpose of the invention]

本発明の目的は、前記した従来技術の問題点に鑑み、簡
単な構成で自動焦点合せが出来るようにした自動焦点合
せ方法を提供するにある。SUMMARY OF THE INVENTION In view of the problems of the prior art described above, an object of the present invention is to provide an automatic focusing method that allows automatic focusing with a simple configuration.

〔発明の概要〕[Summary of the invention]

本発明は、上記目的を達成するために映像の平均値処理
もしくは平滑化を施したものと、何ら処理を施さないも
のの差が最大になる点を求めることにより、焦点合せを
行うようにしたことを特徴とするものである。In order to achieve the above object, the present invention performs focusing by determining the point where the difference between the average value processing or smoothing of the image and the image without any processing is maximized. It is characterized by:

〔発明の実施例〕[Embodiments of the invention]

以下、本発明の一実施例を第２図乃至第５図にもとづい
て具体的に説明する。第２図は自動焦点合せの機能図で
ある。カメラ６からの出力映像信号９を平均値処理手段
もしくは平滑化手段７に通し、比較器８で高周波成分の
除去された映像信号１０とカメラ６からの生の出力映像
信号９とを画面全体もしくは比較してその差を求め、画
面全体もしくは指定エリアについて加算して出力１１を
求め、対象物又は結像レンズとカメラ６とを光軸方向に
相対的移動（変位）させながらその分散を求め、その分
散の最大となる合焦点位置に調節する。自動焦点合せの
後対象物の寸法測定、位置認識が容易に行えるように、
これらの機能を第６図のビデオＲＡＭ装置で構成した。Hereinafter, one embodiment of the present invention will be specifically described based on FIGS. 2 to 5. FIG. 2 is a functional diagram of automatic focusing. The output video signal 9 from the camera 6 is passed through the average value processing means or the smoothing means 7, and the video signal 10 from which high frequency components have been removed by the comparator 8 and the raw output video signal 9 from the camera 6 are combined with the entire screen or Compare and find the difference, add for the whole screen or a designated area to find the output 11, and find the dispersion while relatively moving (displacing) the object or the imaging lens and the camera 6 in the optical axis direction, The focal point position is adjusted to maximize the dispersion. After automatic focusing, it is easy to measure the dimensions and recognize the position of the object.
These functions were configured by the video RAM device shown in FIG.

第３図は市販のビデオＲＡＭ装置であυ、カメラ１２か
らの映像を画像メモリ１３に入力する。FIG. 3 shows a commercially available video RAM device υ, which inputs images from a camera 12 to an image memory 13.

画像メモリＶ；コンピュータ１４からアクセスでき、第
２図の機能をソフトウェアで実現する。第２図の平均値
処理機構７は、例えば第４図で示す３×３絵素の平均値
ぬ′なる値ｖ’−（、↓ｏ■・）／９を求め、第２図の
比較器８で、今求めた平均値処理された画像ｖ’＝（、
着。■）／９と未処理画像■とを第２図の比較器８で比
較し、その差（ｖ、’＝Ｖ６）を画像全体もしくは指定
エリア内について加算する。そして対象物又は結像レン
ズとカメラ６とを光軸方向に相対的に移動させながらそ
の変位量を変位検出手段で検出すると共に、上に加算さ
れた出力の分散を求めると第５図のようになる。この分
散が最大となる点が指定エリアに対する合焦点位置であ
る。勿論、第２図の機能をハードウェアで構成してもよ
い。その場合、第２図のブロック７は、ローパスフィル
タカラ構成された平滑化手段である。Image memory V; can be accessed from the computer 14, and realizes the functions shown in FIG. 2 by software. The average value processing mechanism 7 in FIG. 2 calculates, for example, the average value of the 3×3 picture elements shown in FIG. 8, the average value processed image v'=(,
Arrived. (2)/9 and the unprocessed image (2) are compared by the comparator 8 in FIG. 2, and the difference (v,'=V6) is added for the entire image or within the specified area. Then, while relatively moving the object or the imaging lens and the camera 6 in the optical axis direction, the amount of displacement is detected by the displacement detection means, and the dispersion of the added output is calculated as shown in Figure 5. become. The point where this dispersion is maximum is the focal point position for the specified area. Of course, the functions shown in FIG. 2 may be configured by hardware. In that case, block 7 in FIG. 2 is a smoothing means configured as a low-pass filter collar.

このように本発明によれば、簡単な構成で自動焦点合せ
が可能となシ、対象物の寸法測定や位置認識と同じ機構
で行うことができる。換言すれば従来のビデオＲＡＭで
自動焦点合せの特別な機構なしで焦点合せから寸法測定
・位置認識を行うことが可能となった。As described above, according to the present invention, automatic focusing is possible with a simple configuration, and can be performed using the same mechanism as measuring the dimensions and recognizing the position of the object. In other words, it has become possible to perform focusing, dimension measurement, and position recognition using a conventional video RAM without a special automatic focusing mechanism.

〔発明の効果〕〔Effect of the invention〕

以上説明したように本発明によれば、簡単な構成で安価
に自動焦点合せを行うことができる効果を奏する。As explained above, according to the present invention, automatic focusing can be performed at low cost with a simple configuration.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は従来自動焦点合せ機構−例を示した図、第２図
〜第５図は本発明の一実施例を示し、第２図は本発明の
自動焦点合せの機能図、第３図はビデオＲＡＭ装置を示
した図、第４図は平均値処理の一実施例を示した図、第
５図は合焦点で比較器出力の分散が最大となることを示
す図である。 ６　カメラ、 ７・・・平均値処理手段もしくは平滑化手段、８　比較
器、　　　　　　９　映像信号、１２・・・カメラ、１
６・・・画像メモリ、１４・　コンピュータ。 第　ｌ　図 ２　　　　３ 第　２　図 ／θ 第　４ｒｙｓ 第　３　図Fig. 1 is a diagram showing an example of a conventional automatic focusing mechanism, Figs. 2 to 5 show an embodiment of the present invention, Fig. 2 is a functional diagram of the automatic focusing mechanism of the present invention, and Fig. 3 4 is a diagram showing a video RAM device, FIG. 4 is a diagram showing an example of average value processing, and FIG. 5 is a diagram showing that the dispersion of the comparator output becomes maximum at a focused point. 6 Camera, 7... Average value processing means or smoothing means, 8 Comparator, 9 Video signal, 12... Camera, 1
6... Image memory, 14. Computer. Fig. 2 3 Fig. 2/θ 4rys Fig. 3

Claims (1)

【特許請求の範囲】[Claims] 対象物体上の像を撮像装置で撮像し、この撮像によって
得られる映像信号に平均値処理または平滑化処理を施し
、この処理を施された信号と処理を施さない信号との差
を検出し、この差が最大となる点を求め、これを合焦点
とすることを特徴とする自動焦点合せ方法。An image on the target object is captured by an imaging device, the video signal obtained by this imaging is subjected to averaging processing or smoothing processing, and the difference between the processed signal and the unprocessed signal is detected, An automatic focusing method characterized by finding the point where this difference is maximum and setting this as the in-focus point.