JPH04367174A - Automatic discriminator for autofocus - Google Patents

Abstract

PURPOSE:To enable an automatic discriminator for autofocus to automatically and accurately check an autofocus matching degree for a video camera by using the pattern matching technique. CONSTITUTION:The section between the TELE end and the WIDE end in the zoom tracking is divided into a plurality of stages. An A/D converter 13 converts into a digital signal an image signal from a video camera 12 that took picture of a special purpose chart 11 for focus auto discrimination having a plurality of marks corresponding to the individual stages in the aforementioned section. This converted signal is accumulated in a digital image memory 14. Further, based on the read start point for pattern data calculated and picked up by a pattern matching section 15, a computer section 16 reads from an image memory 14 ten and a few points of individual pattern profile data corresponding to each mark of the special purpose chart 11, and analyses this read data to discriminate a focus matching degree at each stage.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic autofocus discrimination device for inspecting the degree of focus in manual focus/zoom tracking of an electronic imaging camera outputting a video signal, such as a video camera or an electronic still camera.

0002

2. Description of the Related Art Conventionally, an automatic focus determination device using a computer has not been used to inspect the degree of focus during zoom tracking because it takes too long to measure.
The system relied on artificial methods in which humans checked the specified recognition marks at the TELE end, then checked again at the zoomed-in WIDE end, and passed the test if the gaps between the recognition marks appeared to be separated by more than the standard.

0003

However, the conventional methods using artificial means have problems in improving the working environment for operators, such as variations in judgment and fatigue due to simple tasks.

SUMMARY OF THE INVENTION The present invention has been made to solve these conventional problems, and it is an object of the present invention to provide an automatic autofocus determination device that can automatically determine the autofocus of a video camera or the like.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention divides the zoom tracking of a video camera, etc. from the TELE end to the WIDE end into a plurality of stages in advance, and each step from the TELE end to the WIDE end. A dedicated chart for autofocus automatic discrimination that has a plurality of marks whose size is determined in advance so that among the marks on the chart imaged at the step, there is a mark of the same size as the reference dimension mark imaged at the TELE end. , an A/D converter that converts a video signal from a video camera or the like that imaged this special chart into a digital signal, a digital image memory that stores the converted digital signal, and a readout of pattern data of the imaged dedicated chart. A pattern matching unit that determines the starting point by referring to standard pattern data, and a computer that analyzes the pattern data in the digital image memory based on the readout starting point and determines the degree of focus at each stage in zoom tracking. It is equipped with a section.

[0006]

[Operation] According to the above-described configuration, the present invention first uses the pattern data of the mark of the reference dimension of the dedicated chart imaged at the TELE end, based on the reading start point of the pattern data calculated by the pattern matching section. By analyzing only the data in the portion where the signal level changes at about 10 points from the reading start point, the degree of focus can be automatically and accurately determined in a short time. Therefore, by performing the same operation on the pattern data of the mark that is the same as the reference dimension at that stage among the data obtained by imaging the dedicated chart in the same way at each stage of zoom tracking,
The degree of focus at each stage in zoom tracking can be automatically determined in order.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of an embodiment of the present invention. In FIG. 1, reference numeral 11 is a dedicated chart for automatic focus determination, with numbers of different sizes on a white background. 1 to No. The boundaries with black circle marks up to 5 have a clear pattern. 12 is a video camera to be inspected;
13 is an A/D converter that converts the video signal output from the video camera 12 into a digital signal, 14 is a digital image memory that stores the A/D converted signal, and 15 is a readout pattern data of the imaged dedicated chart 11. A pattern matching unit that determines the starting point by referring to standard pattern data; 16 is a digital image memory 14;
17 is a CRT monitor section; 18 is a computer section such as a measurement system processor that automatically determines the degree of focus at each stage in zoom tracking by analyzing the data stored in the pattern matching section 15;
are peripheral devices such as a keyboard, an external storage memory, and a CRT.

The pattern matching unit 15 includes a binarization converter 19 that binarizes the digital data converted by the A/D converter 13, a binary memory 20 that stores the binarized data, and a dedicated chart 11. Comparing the data from the matching memory 21 and binary memory 20 that store standard pattern data with the data from the matching memory 21,
The pattern readout start point calculation unit 22 determines the readout start point of data obtained by imaging the dedicated chart 11.

Next, the basic operation of the above embodiment will be explained with reference to FIG. FIG. 2A shows mark No. 1 having the standard dimensions of the dedicated chart 11 obtained by imaging with the video camera 12. 1 is converted into a digital signal by the A/D converter 13 and stored in the digital image memory 14.
The pattern data written in is shown. Then, this pattern data is binarized by a binarization converter 19 and stored in a binary memory 20, and at the same time, the pattern readout start point calculation unit 22 refers to the matching memory 21 storing the regular standard pattern data. The starting point for reading out the pattern data is determined. For example, when the readout start point is determined at position P in FIG. By reading the dedicated chart 1
1 mark no. It is possible to obtain data for one contour. The data of this pattern outline is shown in Figure 2 (B) and (C).
Shown below. FIG. 2(B) shows a case where the camera is focused, and FIG. 2(C) shows a case where the camera is out of focus. In other words, when the focus is on,
If the number of intermediate level data during the transition from the white level to the black level is small and the focus is out of focus, the number of intermediate level data increases. Conversely, by determining the number of intermediate level data in this case, it is possible to determine the degree of focus.

Therefore, as shown in FIG. 3, the maximum enlarged image 2 in zoom tracking of the video camera 12
The range from the TELE end where 3 is obtained to the WIDE end where the minimum reduced image 24 is obtained is divided into 5 stages from S1 to S5, and the mark No. TEL 1
Reference data corresponding to the pattern data when imaged at the E end is registered in the matching memory 21. Then, at stage S1, which is the TELE end, mark No. In step S2, the reduced mark No. 1 is adjusted so that the image data of No. 1 matches the reference data. In step S3, mark No. 2 is further reduced so that the imaged data of No. 2 matches the reference data. In step S4, mark No. 3 is further reduced so that the imaging data of No. 3 matches the reference data. 4 so that the imaging data matches the reference data, and step S5
Now, mark No. which has been further reduced. Each dedicated chart 11 is used to match the imaging data of No. 5 with the reference data.
Mark No. above. 1 to No. Determine the size of 5. Then, the corresponding mark No. in each stage S1 to S5. 1 to No. By matching the imaging data of No. 5 with the reference data using the method described above, it becomes possible to automatically determine the degree of focus at each stage S1 to S5.

As described above, according to the above embodiment, the zoom tracking of the video camera 12 from the TELE end to the WIDE end is divided into five stages from S1 to S5, and at each stage, the corresponding mark on the dedicated chart 11 is No. 1~No. Since the degree of focus is automatically determined by matching data obtained by imaging 5 and reference data, the degree of focus during zoom tracking of the video camera can be accurately inspected in a short time without human intervention.

[0012] Note that the mark No. of the dedicated chart 11. 1
~No. By making 5 circular, dedicated chart 11
Mark No. above. 1~No. Even if the position of 5 and the video camera that images it are shifted in the rotational direction, pattern matching can be performed reliably.

[0013] Also, mark No. 1 and no. By arranging the same mark in two places on the left and right as shown in 2, even if the positions of the dedicated chart 11 and the video camera 12 shift to the left or right at the TELE end where the image is enlarged, at least one mark will remain can be placed within the field of view of the video camera.

[0014]

Effects of the Invention As is clear from the above embodiments, the present invention improves TE in zoom tracking of video cameras, etc.
A dedicated chart that divides the range from the LE end to the WIDE end into multiple stages and has multiple marks of sizes corresponding to each stage, and converts the video signal from a video camera, etc. that captured the chart into a digital signal. a /D converter, a digital image memory for storing converted digital signals, a pattern matching section that determines a readout start point of pattern data of the imaged dedicated pattern by referring to standard pattern data, and a pattern matching unit that determines the readout start point of pattern data of the imaged dedicated pattern; It is equipped with a computer section that analyzes the read data from the digital image memory and determines the degree of focus at each stage in zoom tracking, so it is possible to determine the degree of focus at each stage of zoom tracking. By simply analyzing the data using a computer, accurate automatic focus determination at each stage can be carried out in a short time, making it possible to introduce it into many inspection lines where takt time is limited.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of an autofocus automatic discrimination device according to an embodiment of the present invention.

[Fig. 2] (A) Schematic diagram showing the contents of the digital image memory in which pattern data obtained by imaging a dedicated chart is written. (B) Diagram showing the image memory read data when the camera focus is on. (C) A diagram showing the data read out from the image memory when the camera focus is on. Diagram showing image memory read data when blurred

[Figure 3] Diagram explaining the matching status at each stage in dedicated chart and zoom tracking

[Explanation of symbols]

11 Dedicated chart for automatic focus detection 12
Video camera 13 A/D converter 14 Digital image memory 15 Pattern matching section 16 Computer section 17 CRT monitor section 18 Peripheral equipment 19 Binarization converter 20 Binary memory 21 Matching memory 22 Pattern reading start point calculation section 23 Maximum enlarged image 24 Minimum reduced image

Claims (2)

[Claims] 1. In zoom tracking of an electronic imaging camera, from the TELE end to the WIDE end is divided in advance into a plurality of stages, and in the mark of the chart imaged by the camera at each stage from the TELE end to the WIDE end, A dedicated chart for autofocus automatic discrimination having a plurality of marks whose size is determined in advance so that there is a mark of the same size as the reference dimension mark imaged at the TELE end, and an electronic type imaged of the dedicated chart. An A/D converter that converts a video signal from an imaging camera into a digital signal, a digital image memory that stores the converted digital signal, and a readout start point of pattern data of the imaged dedicated chart using standard pattern data. a pattern matching section that determines by reference; and a computer section that analyzes the pattern data in the digital image memory based on the readout start point and determines the degree of focus at each stage in the zoom tracking. Autofocus automatic discrimination device. 2. The autofocus automatic discrimination device according to claim 1, wherein each of the plurality of marks is circular.