JP2006245891A - Chart for inspecting image of camera module, and image inspecting method and image inspecting device for the camera module using the chart for inspecting image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chart for inspecting an image of a camera module in which an image inspection time period is short and the image of the camera module can be inspected with the good productivity, or to provide an image inspecting device in which the image inspection time period is short and the image of the camera module can be inspected with the good productivity. <P>SOLUTION: The chart for inspecting the image of the camera module is a chart for inspecting an image for inspecting image quality photographed by the camera module, and a resolution inspecting area 2 and a color repeatability inspecting area 3 are disposed in one inspecting chart 11. Further, the image inspecting device of the camera module has an imaging means for imaging the chart for inspecting the image by use of the chart for inspecting the image; and a performance evaluating means for evaluating the performance of the camera module, based on an taken image of the chart for inspecting the image obtained by the imaging means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image inspection chart used for image inspection (resolution inspection and color reproducibility inspection) of a camera module mounted on a mobile phone or the like, an image inspection method and an image inspection apparatus using the image inspection chart. It is.

Conventionally, in an image inspection of a small camera module, inspections such as a luminance level, a color phase, an image resolution, and the presence / absence of dust are performed.
At this time, the imaging environment for the inspection needs to be a plurality of environments such as luminance level measurement, color phase measurement, and image resolution measurement, each of which can be inspected with separate devices, or on one inspection device, It was necessary to change the inspection environment for measurement (for example, change the measurement chart for each measurement).

For example, an image inspection apparatus for a camera module and an image inspection method for a camera module disclosed in JP-A-2002-232918 (Patent Document 1) will be described with reference to FIG.
7, 101a to 101d are camera modules to be inspected, 102 is a PCI (Peripheral Component Interconnect) board, 103 is a personal computer, and 104 is a monitor.
As shown in FIG. 7, for example, four camera modules 101 a to 101 d are installed on a connection jig (not shown) connected to the PCI board 102 in the personal computer 103.
Reference numerals 105a to 105d denote subjects (for example, image inspection charts) photographed by the camera modules 101a to 101d, respectively. These subjects (image inspection charts) have exactly the same conditions (for example, illuminance, large size). The distance to the subject, the angle of view, etc.).

When the camera modules 101a to 101d and the personal computer 103 are turned on, the camera modules 101a to 101d start to operate, and 8-bit RGB digital video signals are continuously output from the camera modules 101a to 101d.
Each camera module 101a to 101d is provided with a buffer memory for one screen in order to improve the processing speed, and outputs an interrupt signal (corresponding to a vertical synchronization signal) when the buffer memory becomes full. The data in the buffer memory is not updated until input of the next data to the buffer memory is started.
Since no particular synchronization is established between the camera modules 101a to 101d, interrupt signals from the camera modules 101a to 101d are output at random.

On the other hand, on the personal computer 103 side, when an interrupt signal is detected using this time, data is quickly taken in from the buffer memory of the camera modules 101a to 101d, and the display (that is, the monitor 104) is sent via the main memory or video memory. Display above.
By repeating this operation, the personal computer 103 displays the images of the four camera modules on the monitor 104 in real time.
As described above, in the image inspection apparatus of the conventional camera module shown in FIG. 7, the brightness levels of a plurality of (for example, four) camera modules are calculated simultaneously, and the brightness levels of the plurality of camera modules are simultaneously compared. Automatically performed by the computer 103 or the like.
In this case, if only one defective product is mixed, it is determined from the comparison data that the product is defective.
The same applies to inspection items such as color phase, image resolution, and presence / absence of dust.
Japanese Patent Laid-Open No. 2002-232918 (FIG. 1, paragraph 0024)

In the conventional image inspection apparatus described above, inspections such as a luminance level, a color phase, an image resolution, and the presence / absence of dust are performed.
At this time, the imaging environment for the inspection needs to be a plurality of environments such as luminance level measurement, color phase measurement, and image resolution measurement.
Therefore, it is necessary to perform inspection with separate devices, or to change the environment on one device (for example, exchange the measurement chart for each measurement), so image inspection time (ie, imaging with a camera module) The time for evaluating the quality of the image to be obtained) becomes long, and the productivity of image inspection of the camera module is poor.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a camera module image inspection chart that can perform image inspection of a camera module with high productivity and a short image inspection time. .
It is another object of the present invention to provide an image inspection method and an image inspection apparatus that can perform image inspection of a camera module with high productivity by using the image inspection chart with a short image inspection time.

  An image inspection chart of a camera module according to the present invention is an image inspection chart for inspecting the quality of an image photographed by a camera module, and includes a resolution inspection area and a color reproducibility inspection area as one. It is arranged in the inspection chart.

  An image inspection method for a camera module according to the present invention includes an imaging step for imaging an image inspection chart using the image inspection chart for the camera module according to the present invention, and an image inspection chart obtained by the imaging step. And a performance evaluation step for evaluating the performance of the camera module based on the captured image.

  An image inspection apparatus for a camera module according to the present invention includes an image pickup means for picking up an image inspection chart using the image check chart for the camera module according to the present invention, and an image inspection chart obtained by the image pickup means. It is characterized by having performance evaluation means for evaluating the performance of the camera module based on the captured image.

According to the image inspection chart of the camera module according to the present invention, since the resolution inspection area and the color reproducibility inspection area are arranged in one chart, the image inspection chart is imaged only once. Thus, it is possible to acquire data for resolution inspection and data for color reproducibility inspection, and image inspection of the camera module can be performed with high productivity.
Further, according to the present invention, since the image inspection chart in which the resolution inspection area and the color reproducibility inspection area are arranged in one chart is used, the camera module can perform the image inspection of the camera module with high productivity. The image inspection method can be provided.
Further, according to the present invention, since the image inspection chart in which the resolution inspection area and the color reproducibility inspection area are arranged in one chart is used, the camera module can perform the image inspection of the camera module with high productivity. An image inspection apparatus can be provided.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the drawings, the same reference sign represents the same or equivalent.
Embodiment 1 FIG.
FIG. 1 is a diagram showing the configuration of an image inspection chart of a camera module according to Embodiment 1 of the present invention.
In the figure, 11 is an image inspection chart of the camera module according to the present embodiment, 2 is a resolution inspection area, and the resolution inspection area 2 is a predetermined position (for example, the central portion O of the image inspection chart 11). A plurality of black and white repeated stripe patterns (that is, patterns in which striped white areas and black areas are alternately repeated) 2a, 2b,.
The resolution inspection area 2 can be used for resolution inspection of an image captured by the camera module by using the edges of the white stripe and the black stripe of a black and white repeated stripe pattern.

Reference numeral 3 denotes a color reproducibility inspection area, and the color reproducibility inspection area 3 includes, for example, white color area 3a, red color area 3b, blue color area 3c, and yellow color area 3d. It consists of two color areas, and can be used for the inspection of the color reproducibility of the image captured by the camera module.
Here, the white color region 3a is for monitoring the luminance signal, and the red / blue color region 3b / 3c is for monitoring the color difference signal.
In addition, in the camera, it is desirable to sensitively observe the yellow reproducibility, so a yellow color region 3d is also provided.
The color reproducibility inspection region 3 is preferably composed of four color regions of white, red, blue, and yellow, but is not necessarily limited to this, and red, blue, green, white, It may be composed of any number of color areas of black, yellow, magenta, and cyan.

As described above, the image inspection chart of the camera module according to the present embodiment has the resolution inspection area 2 and the color reproducibility inspection area 3 arranged in one chart. It is possible to acquire data for resolution inspection and data for color reproducibility inspection by imaging the chart once, and the resolution inspection and the color reproducibility inspection which have been performed separately so far can be performed in one test at the same time. It can be carried out.
As a result, the image inspection time of the camera module can be greatly shortened, and productivity can be improved.

Embodiment 2. FIG.
FIG. 2 is a diagram illustrating a configuration of an image inspection chart of the camera module according to the second embodiment.
As shown in the figure, the image inspection chart 12 of the camera module according to the present embodiment is further arranged at predetermined positions at the four corners in the peripheral portion of the image inspection chart of the camera module according to the first embodiment shown in FIG. A plurality of second repeating stripe patterns 4a, 4b,... Formed by a plurality of black and white repeated stripe patterns 4a, 4b,. The resolution inspection area 4 is further arranged.

In other words, the resolution inspection area of the image inspection chart of the camera module according to the present embodiment is the first resolution inspection comprising the black and white repeated stripe patterns 2a, 2b,... Extending radially from the center of the inspection chart. For a second resolution inspection comprising a black and white repetitive stripe pattern 4a, 4b,... Extending radially from the center point within a circle of an arbitrary radius centered at a predetermined position on the periphery of the inspection chart It is configured in combination with the region 4.
By using the second resolution inspection regions 4 arranged at the four corners that are the peripheral portion of such an inspection chart, the resolution of the peripheral portion of the image can be inspected with high accuracy.

Embodiment 3 FIG.
FIG. 3 is a diagram showing a configuration of an image inspection chart of the camera module according to the third embodiment.
In FIG. 3, reference numeral 5 denotes an alignment mark. As shown in FIG. 3, the image inspection chart 13 of the camera module according to the present embodiment is an image of the camera module according to the first embodiment shown in FIG. An alignment mark 5 for detecting the inspection position of the inspection chart is further arranged on the inspection chart 11.
In the example of FIG. 3, the alignment mark 5 is composed of a white square and a black circle.
The alignment mark 5 has a plurality of black and white repeated stripe patterns (that is, a pattern in which striped white areas and black areas are alternately repeated) extending radially from the center of the image inspection chart 13. In the vicinity of the center of the resolution inspection area 2 formed by 2b,..., Two are arranged symmetrically with respect to the center O of the inspection chart.

Since the shape of the black circle does not change even if it rotates, the alignment mark 5 can be changed to a black circle so that the position can be accurately recognized even when the camera or the inspection chart is rotated.
Further, by arranging a black circle in a white square, the contrast becomes high and the alignment mark can be easily recognized.
Further, by arranging two alignment marks 5 symmetrically with respect to the center portion O of the inspection chart, it is possible to remove contrasting distortion of the image. Further, by using two alignment marks 5, it is possible to recognize and correct a change in the magnification of the image. It is also possible to perform XY correction, θ correction, and magnification correction from the two alignment marks.

In a conventional method that does not use alignment marks, a camera module (imaging device) is mechanically positioned to capture an image inspection chart. And the specific site | part of the imaged image is used for a test | inspection.
However, in the conventional method based on this mechanical positioning, the captured image is slightly displaced due to assembly variations of the camera module (imaging device).
For this reason, there is a possibility that an inspection of a portion deviated from the intended inspection area is performed.
On the other hand, in the image inspection chart 13 of the camera module according to the present embodiment, an alignment mark for detecting the position of the inspection location is arranged. It is possible to correct inspection region variations due to assembly variations of an object (that is, an image sensor as a camera module).

In other words, by using the image inspection chart of the camera module according to the present embodiment, the position of the inspection area of the captured image is slightly shifted (for example, several tens of elements) due to assembly variations of the image sensor. Even if this is the case, the inspection location can be automatically determined by the alignment mark 5, so that an accurate inspection can be performed.
Therefore, the productivity of image inspection of the camera module can be improved without deteriorating the quality of inspection.

Embodiment 4 FIG.
FIG. 4 is a diagram for explaining an image inspection method for a camera module according to Embodiment 4 of the present invention.
4 is an image inspection chart of the camera module in which the alignment mark 5 described in the third embodiment is further arranged with respect to the image inspection chart (FIG. 2) of the camera module according to the second embodiment. , A thick solid line circle 20 indicating the resolution inspection area (in the center and four corners) and a thick solid line square indicating the color reproducibility inspection area (in each of the four color areas).
FIG. 5 is a flowchart for explaining a camera module image inspection method according to the fourth embodiment.

Next, a camera module image inspection method according to the fourth embodiment will be described with reference to FIGS.
First, the image inspection chart 14 shown in FIG. 4 is imaged to obtain image data. (Processing step S1).
Next, from the alignment mark 5 in the obtained image data, the center of the image inspection chart 14 and a preset inspection region (that is, a circle 20 and a square 30 indicated by a thick solid line) are calculated. (Processing step S2)
A resolution evaluation value and a color reproducibility evaluation value are calculated from the calculated image data of the inspection region. (Processing step S3)

Then, regarding the resolution and color reproducibility, the evaluation value obtained in the processing step S3 is compared with the inspection standard value, and it is determined whether or not the evaluation value satisfies a predetermined inspection standard value. (Processing step S4)
The inspection method thus obtained enables inspection and determination of resolution and color reproducibility by one imaging.
As a result, it is possible to simultaneously perform the resolution inspection and the color reproducibility inspection that have been separately performed until now, and the inspection time can be greatly shortened.

As described above, the image inspection method of the camera module according to the present embodiment is obtained by the imaging step of imaging the image inspection chart using the image inspection chart of the camera module according to the present invention, and the imaging step. A performance evaluation step for evaluating the performance of the camera module based on the captured image of the image inspection chart.
As a result, it is possible to simultaneously perform the resolution inspection and the color reproducibility inspection that have been separately performed until now, and the inspection time can be greatly shortened.

Embodiment 5. FIG.
FIG. 6 is a diagram showing a configuration example of an image inspection apparatus for a camera module according to Embodiment 5 of the present invention.
In the figure, 51 is an image inspection chart according to the present invention, and the image inspection chart of any of the image inspection charts 11, 12, 13, 14 described in the first to fourth embodiments is used. It is done.
The image inspection chart 51 receives light from the light source 52 and images it with an image sensor (camera module) 54 to be inspected through a filter 53 (for example, an ND filter or a color temperature conversion filter).

If there is a difference between the light source required for inspection and the actual light source, the filter 53 uses an ND filter (neutral density filter) for illuminance and a color temperature conversion filter for color temperature. The light source state is corrected.
Reference numeral 55 denotes a fixing jig that fixes and electrically connects the image sensor (camera module) 54, 56 is a dark box that isolates the imaging environment from the outside, 60 is an arithmetic processing unit, and 70 is imaging. It is a display device (monitor) that displays the image and the inspection result.
The light source 52, the filter 53, the image pickup device 54, the fixing jig 55, the dark box 56, and the like constitute image pickup means in the image inspection apparatus for the camera module according to this embodiment.

Next, the operation of the camera module image inspection apparatus according to the fifth embodiment will be described with reference to the flowchart of FIG.
The light emitted from the light source 52 is reflected by the image inspection chart 11 and enters the image sensor 54 (camera module) through the filter 53.
The imaging element (camera module) 54 captures an incident image and acquires image data. (Processing step S1)
The obtained image data is calculated by the arithmetic processing unit 60 from the alignment mark 5 in the image and the center of the image inspection chart 10 and a preset inspection region. (Processing step S2)

Next, the arithmetic processing device 60 calculates a resolution evaluation value and a color reproducibility evaluation value from the calculated image data of the inspection region. (Processing step S3)
Then, regarding the resolution and color reproducibility, the arithmetic processing device 60 compares the evaluation value obtained in the processing step S3 with the inspection standard value, and determines whether or not the evaluation value satisfies a predetermined inspection standard value. Judgment is made. (Processing step S4)
As described above, the arithmetic processing device 60 is based on the captured image of the image inspection chart obtained by the imaging means (the light source 52, the filter 53, the imaging element 54, etc.) in the image inspection device of the camera module according to the present embodiment. Thus, it becomes a performance evaluation means for evaluating the performance of the camera module.
The display device (monitor) 70 displays an image picked up by the image pickup device (camera module) 54 and displays an evaluation value of resolution / color reproducibility calculated by the arithmetic processing device 60.

As described above, the image inspection apparatus for a camera module according to the present embodiment has an image pickup means (light source 52, filter 53, image pickup) for picking up an image inspection chart using the image inspection chart for a camera module according to the present invention. Element 54) and performance evaluation means (that is, the arithmetic processing unit 60) for evaluating the performance of the camera module based on the captured image of the image inspection chart obtained by the imaging means.
Therefore, according to the present invention, since the image inspection chart in which the resolution inspection area and the color reproducibility inspection area are arranged in one chart is used, the resolution inspection and the color reproducibility inspection are simultaneously performed by one imaging. Thus, the inspection time can be greatly shortened, so that the image inspection of the camera module can be performed with high productivity.

  INDUSTRIAL APPLICABILITY The present invention is useful for realizing an image inspection method or an image inspection apparatus that can perform image inspection of a camera module with high productivity with a short image inspection time.

It is a figure which shows the structure of the chart for image inspection of the camera module by Embodiment 1 of this invention. It is a figure which shows the structure of the chart for image inspection of the camera module by Embodiment 2 of this invention. It is a figure which shows the structure of the chart for an image test | inspection of the camera module by Embodiment 3 of this invention. It is a figure for demonstrating the image inspection method of the camera module by this invention. 3 is a flowchart for explaining an image inspection method of a camera module according to the present invention. It is a figure which shows the structure of the image inspection apparatus of the camera module by this invention. It is a figure which shows the structure of the image inspection apparatus of the conventional camera module.

Explanation of symbols

11, 12, 13, 14 Chart for image inspection of camera module 2 Resolution inspection area 2a, 2b, 2c, 2d Repeated black and white stripe pattern 3 Color reproducibility inspection area 3a White color area 3b Red color area 3c Blue Color area 3d Yellow color area 4 Resolution inspection area 4a, 4b, 4c, 4d Black and white repeated stripe pattern of resolution inspection area 4 O1, O2, O3, O4 Resolution inspection arranged at the four corners Center point of area 4 5 Alignment marks 20, 30 Inspection area 51 Chart for image inspection of camera module 52 Light source 53 Filter 54 Image sensor 55 Fixing jig 56 Dark box 60 Arithmetic processing unit 70 Display unit

Claims (9)

An image inspection chart for inspecting the quality of an image taken by a camera module,
An image inspection chart of a camera module, wherein a resolution inspection area and a color reproducibility inspection area are arranged in one inspection chart.   2. The image inspection chart for a camera module according to claim 1, wherein the resolution inspection area is formed by a black and white repeated stripe pattern extending radially from a predetermined position in the inspection chart.   2. The image inspection chart for a camera module according to claim 1, wherein the color reproducibility inspection area is composed of four colors of white, yellow, red and blue.   The resolution inspection area extends radially from the central point within a circle of repeated black and white stripes extending radially from the center of the inspection chart and an arbitrary radius centered at a predetermined position on the periphery of the inspection chart. 2. The image inspection chart for a camera module according to claim 1, comprising a combination with a black and white repetitive stripe pattern.   The chart for image inspection of the camera module according to claim 1, wherein an alignment mark for detecting an inspection position is arranged.   6. The chart for image inspection of a camera module according to claim 5, wherein the alignment mark includes a white square and a black circle arranged in the square.   6. The image inspection chart for a camera module according to claim 5, wherein two alignment marks are arranged symmetrically with respect to a center portion of the inspection chart. An imaging step of imaging the image inspection chart using the image inspection chart of the camera module according to any one of claims 1 to 7,
An image inspection method for a camera module, comprising a performance evaluation step for evaluating the performance of the camera module based on a captured image of the image inspection chart obtained by the imaging step. Imaging means for imaging an image inspection chart using the image inspection chart of the camera module according to any one of claims 1 to 7,
An image inspection apparatus for a camera module, comprising performance evaluation means for evaluating the performance of the camera module based on a captured image of the image inspection chart obtained by the imaging means.

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