JP7308131B2 - optical adjuster - Google Patents

Description

The present invention relates to an optical adjustment device for adjusting the optical axis of a camera module.

Door slave units that constitute an intercom device are widely used that are equipped with a camera. When assembling the camera in this entrance child device, there is a process of mounting the lens holder that constitutes the camera module on the camera board equipped with the image sensor, and in this process focus adjustment and correction of optical axis deviation are performed ( For example, see Patent Document 1).

JP 2010-197959 A

An image without distortion can be obtained by correcting the optical axis misalignment, but this correction sometimes causes so-called lens shading, in which the periphery of the captured image becomes dark or colored. However, this shading correction was not performed together.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an optical adjustment device that improves the image output from a camera module by performing shading correction in accordance with optical axis adjustment. .

In order to solve the above-mentioned problems, the invention of claim 1 provides a lens holder that holds a lens, when a camera module is manufactured by attaching a lens holder to a camera substrate having an image sensor, the center of the lens and the center of the image sensor are aligned. An optical adjustment device for correcting an optical axis misalignment that occurs between a camera adjustment table on which a camera module is placed, an image input unit for inputting an image signal captured by an image sensor, and an image input unit and a control/judgment unit for judging the direction and distance of the optical axis misalignment based on the image information of the image sensor. Based on the captured image signal, the direction and distance of the optical axis misalignment are determined to determine the optical axis misalignment correction value, and the point shifted by the optical axis misalignment correction value is used as the starting point of the shading correction. do.
According to this configuration, after performing the optical axis shift correction of the camera module, the point shifted by the correction value is used as the starting point of the shading correction. It is possible to obtain a good image with no bias in image quality.

According to the second aspect of the invention, in the configuration of the first aspect, the camera module includes, in addition to the lens holder and the image sensor, an image signal processing unit that processes image data output from the image sensor. The unit and the image signal processing unit are connected by a transmission line, and the optical axis deviation correction value can be transmitted to the image signal processing unit. The correction start point is set in the image signal processing unit.
According to this configuration, since the point shifted by the optical axis deviation correction value is set as the shading correction start point in the image signal processing section of the camera module, the correction can be performed even if the camera module is subsequently removed from the camera adjustment table. Images can be output.

According to a third aspect of the invention, there is provided the configuration according to the second aspect, wherein the image signal processing unit stores a correction value used for shading correction, and performs shading correction using the correction value. do.
According to this configuration, shading correction can be performed with simple control.

According to the present invention, after correcting the optical axis misalignment of the camera module, the shading correction is performed using the correction value as a starting point of the shading correction. , it is possible to obtain an image with no deviation in image quality.

1 is a configuration diagram showing an example of an optical adjusting device according to the present invention; FIG. FIG. 4 is an explanatory diagram of a camera module; It is a focus and optical-axis adjustment chart figure. 9 is a flowchart of shading correction processing; FIG. 10 is an explanatory diagram of optical axis adjustment and shading correction, in which (a) shows a state in which the optical axis center is aligned, (b) shows a case in which it is shifted to the left, and (c) shows a case in which it is shifted downward. . It is a captured image explaining the generated shading. 7 shows the luminance level of the captured image of FIG. 6. FIG. 7 is a picked-up image in which the shading in FIG. 6 is corrected; 9 shows the luminance level of the captured image of FIG. 8. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments embodying the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram showing an example of an optical adjustment apparatus according to the present invention. A camera adjustment table 2 on which a camera module 1 to be adjusted is mounted, and an imaging operation of the arranged camera module 1 are performed to obtain the captured image. It comprises an image input unit 3 and a control/judgment unit 4 that detects the amount of optical axis deviation and shading from the image obtained by the image input unit 3 and sets the correction amount.

FIG. 2 is an explanatory diagram of the camera module 1 to be adjusted. In the camera module 1, as shown in FIG. 2, a lens holder 11 having a lens 11a attached thereto is fixed by a screw 14 to a camera substrate 13 having an image sensor 12 attached thereto. Here, the lens holder 11 is screwed at two locations on the left and right. The cross mark shown in FIG. 2 indicates the center M of the optical axis, and the optical axis deviation is corrected so that the center M of the image sensor 12 and the center of the lens 11a coincide. Reference numeral 1a denotes an image signal processing unit composed of an ISP that processes signals output from the image sensor 12. FIG.

The optical axis adjustment and shading correction of the camera module 1 configured as described above are performed as follows. First, focus adjustment is performed, and then optical axis adjustment and shading correction are performed.
A camera module 1 is installed on a camera adjustment table 2. - 特許庁When the camera module 1 is installed on the camera adjustment table 2, the first connection section 21 is connected to the image input section 3 via the transmission line L1, and the second connection section 21 is connected to the control/judgment section 4 via the transmission line L2. 2 connections 22 are provided.
When the camera module 1 is installed in this manner, the camera module 1 is connected to the image input section 3 and the control/judgment section 4 , the camera module 1 is activated, and the captured image is transmitted to the image input section 3 .

The image input unit 3 and the control/judgment unit 4 are connected, and the control/judgment unit 4 calculates a correction value and the like from the image data captured by the camera module 1 input to the image input unit 3. Send to camera module 1.

When the camera module 1 is installed on the camera adjustment table 2, the lens holder 11 before focus adjustment is assembled. Focus adjustment is performed while confirming the captured image on the external monitor.

FIG. 3 shows a focus and optical axis adjustment chart G used at this time. As shown in FIG. 3, the one on which a large number of vertical and horizontal patterns with high contrast are formed is used. While viewing this pattern image captured by the camera module, the lens holder 11 is manually moved to adjust the focus so that the center of the image sensor 12 and the center of the lens 11a are aligned as shown in FIG. Then, when the camera is in focus, the lens holder 11 is fixed by screwing it to the camera substrate 13 at two places on the left and right.

After the lens holder 11 is fixed, the video signal of the camera module 1 is input to the image input unit 3, and the control/judgment unit 4 judges the optical axis deviation direction. This determination will be described with reference to the flow chart of FIG.
After recognizing the captured image of the focus/optical axis adjustment chart G (S1), the control/judgment unit 4 determines whether there is a shift in the center position of the focus/optical axis adjustment chart G, and if there is a shift, which position (direction) in the imaging range. , distance) (S2). If there is optical axis misalignment, correction values (X, Y coordinates) are calculated (S3). The optical axis deviation correction value is set so as to move in the direction opposite to the deviation direction.

The calculated optical axis deviation correction value is transmitted to the camera module 1 and stored in the image signal processing section 1a. After that, the camera module 1 outputs image data whose optical axis has been adjusted by this correction value. If there is no optical axis deviation, correction setting is not performed (S4).

5A and 5B are explanatory diagrams of the optical axis adjustment, in which (a) shows a state in which the optical axis center M is aligned, (b) shows a case in which it is shifted to the left, and (c) shows a case in which it is shifted downward. , M1 indicate optical axis adjustment points. In this manner, the correction value is set so that when there is optical axis misalignment, the optical axis moves in the direction opposite to the misaligned direction.
Then, the point shifted by this correction value is set as the shading correction start point (S5). In this way, by causing the camera module 1 to take an image of a predetermined chart and adjusting the optical axis, it is possible to perform the subsequent shading correction satisfactorily.

Shading correction values are stored in advance in the image signal processing unit 1a, and shading correction is performed using the stored shading correction values with the correction value for optical axis adjustment as a starting point. In this way, the image data after the optical axis adjustment and shading correction are output from the image signal processing section 1a.
FIG. 6 is a captured image illustrating the shading that has occurred, and FIG. 7 shows the brightness levels of the captured image of FIG. 8 shows a captured image in which the shading in FIG. 6 is corrected, and FIG. 9 shows the luminance level of the captured image in FIG.

In this way, if there is an optical axis misalignment, unevenness (unevenness) will appear somewhere in the captured image due to shading. Therefore, the effect of image quality improvement (especially peripheral visibility improvement) is large.
After correcting the optical axis misalignment of the camera module 1, the shading correction is performed with the point shifted by the correction value as the starting point of the shading correction. Therefore, in the process of manufacturing the camera module 1, it is possible to obtain a good image with no bias in image quality.
Further, since the point shifted by the optical axis deviation correction value is set as the shading correction start point in the image signal processing section 1a of the camera module, the camera module will output the corrected image even if it is removed from the camera adjustment table thereafter. can.
Further, since the shading correction is performed using a predetermined shading correction value, the shading correction can be performed with simple control.

In the above-described embodiment, the image signal processing unit 1a of the camera module 1 stores the shading correction value in advance, but the control/judgment unit 4 stores the correction value of the optical axis misalignment to the image signal processing unit 1a. When transmitting, it may be transmitted together and stored.

Reference Signs List 1 Camera module 1a Image signal processing unit 2 Camera adjustment base 3 Image input unit 4 Control/judgment unit 11 Lens holder 11a Lens 12 Image sensor 13 Camera substrate 14 Screw G Focus and optical axis adjustment chart M Optical axis center. M1: correction point (shading correction starting point), L2: transmission line.

Claims (3)

Optical adjustment for correcting the optical axis misalignment that occurs between the center of the lens and the center of the image sensor when a camera module is manufactured by attaching a lens holder that holds a lens to a camera board equipped with an image sensor. a device,
a camera adjustment base on which the camera module is mounted;
an image input unit to which an image signal captured by the image sensor is input;
a control/determination unit that determines the direction/distance of the optical axis deviation based on the image information of the image input unit;
The control/judgment unit judges the direction and distance of the optical axis displacement based on the image signal obtained by the image sensor capturing the predetermined focus and optical axis adjustment chart input to the image input unit, and detects the optical axis displacement . 1. An optical adjusting device, wherein a correction value is obtained, and a point shifted by the optical axis deviation correction value is used as a starting point of shading correction. The camera module includes, in addition to the lens holder and the image sensor, an image signal processing unit that processes image data output by the image sensor,
the control/determination unit and the image signal processing unit are connected by a transmission line, and the optical axis deviation correction value can be transmitted to the image signal processing unit;
2. The optical adjustment device according to claim 1, wherein the control/judgment section sets a point shifted by the optical axis deviation correction value as a shading correction start point in the image signal processing section. 3. The optical adjusting device according to claim 2, wherein the image signal processing unit stores a correction value used when performing shading correction, and uses the correction value to perform shading correction.

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