KR100651836B1 - System and method of adjusting image sensor six-axis - Google Patents

Abstract

A system and a method for adjusting six axes of an image sensor are provided to obtain the optimum location of the image sensor while the subjective judgment of human is excluded while on assembling a camera lens module. A motor(260) moves the location of an image sensor to adjust six axes. An image acquisition unit(230) receives a signal from the image sensor and acquires an object image. A computer(245) analyzes the object image to output a control signal for moving the location of the image sensor. A motor driver(250) drives the motor correspondingly to the control signal.

Description

System and Method of Adjusting Image Sensor Six-Axis}

1 is a diagram illustrating six axes for determining a position of an image sensor.

2 is a block diagram of an image sensor 6-axis adjusting system according to a preferred embodiment of the present invention.

3 is a diagram illustrating an example of an image processing chart.

4 is a flowchart illustrating an embodiment of a z-axis adjusting process in the image sensor 6-axis adjusting method according to the present invention.

5 is a side view when the z-axis is adjusted.

6 is a flowchart illustrating an embodiment of an x-axis and y-axis adjusting process in the image sensor 6-axis adjusting method according to the present invention.

7 is a perspective view (a) and a front view (b) when the x-axis and the y-axis are adjusted.

8 is a flowchart illustrating an embodiment of a c-axis adjusting process in the image sensor 6-axis adjusting method according to the present invention.

9 is a perspective view (a) and a front view (b) when the c-axis is adjusted.

10 is a flowchart illustrating an embodiment of an a-axis and b-axis adjustment process in the image sensor 6-axis adjustment method according to the present invention.

11 is a side view when the a-axis is adjusted.

12 is a plan view when the b-axis is adjusted.

The present invention relates to a camera lens module, and more particularly, to an image sensor 6-axis adjustment system and method capable of automatically adjusting the position of the image sensor when the camera lens module is assembled.

Recently, digital cameras have become higher and smaller, and image quality has become a major factor in camera performance. In particular, as the mobile communication terminal is equipped with a high pixel image sensor, a zoom function and an auto focusing function, the demand for lens modules is increasing.

The performance of the lens and camera will vary depending on how precisely the lens module is manufactured. Lens design is also an important factor, but how much the designed lens is assembled to match the design value is also an important variable.

Since the conventional camera module uses a low pixel and short focal length lens, assembly is performed only by the distance between the instruments depending on the design value of the apparatus, and the assembly can be maintained to some extent even in this manner. However, in the case of the high pixel image sensor, if the assembly state of the image sensor is not verified during the assembling process, the image may be distorted or out of focus.

Therefore, in the case of the lens module equipped with a high-pixel image sensor, the lens module is assembled through a process of confirming the assembly state while directly watching an image. That is, in the assembly of a conventional lens module, the assembler used a method of manually determining the position of the image sensor by looking at the screen of the board.

1 is a diagram illustrating six axes for determining a position of an image sensor.

Referring to FIG. 1, the six axes are as follows.

First, the movement in the x- and y-axis directions adjusts the center of the image sensor to the optical axis of the lens, and the movement in the z-axis direction adjusts the plane of the image sensor to the focal position of the lens. It plays a role. In addition, the movement in the a-axis and the b-axis direction allows the image plane of the image sensor to maintain the plane, and the movement in the c-axis direction serves to prevent the image from tilting. In general, the movement in the a-axis direction is called a roll operation, the movement in the b-axis direction is called a pitch operation, and the movement in the c-axis direction is called a yaw operation.

According to the related art, when the image sensor is positioned at the position determined to be optimal through the image of the camera device while changing the respective axes, the assembly unit assembles the lens module and the image sensor at the position.

However, the method of assembling the camera lens module according to the conventional technology described above has the following problems.

First, since the position of the image sensor is found by the judgment of the assembler, the characteristics of the product may vary according to the subjective judgment of the individual assembler, and there may be a mistake.

Second, in the assembly process of the camera lens module that requires a fine adjustment, it takes a long time to find the position of the image sensor depending on the human vision and perception.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an image sensor 6-axis adjustment system and method that can find the optimal image sensor position without subjective human judgment.

Another object of the present invention is to provide an image sensor six-axis adjustment system and method for shortening the assembly time of a camera lens module by automating the six-axis adjustment of the image sensor.

Still another object of the present invention is to provide an image sensor 6-axis adjustment system and method capable of minimizing the quality difference between products by automating the image sensor 6-axis adjustment.

As an aspect of the present invention for achieving the above object, the image sensor 6-axis adjustment system according to the present invention, in manufacturing a camera lens module having a lens and an image sensor, automatically adjusts the six axes of the image sensor A system for performing the above, comprising: a motor for adjusting six axes by moving a position of the image sensor; An image acquisition unit receiving a signal from the image sensor to obtain an image of a subject; A computer including a control unit which analyzes the subject image received from the image acquisition unit and outputs a control signal for moving the position of the image sensor; And a motor driver for driving the motor in response to the control signal.

In another aspect of the present invention, the image sensor 6-axis adjusting method according to the present invention, in manufacturing a camera lens module having a lens and an image sensor using a computer system capable of driving a motor, the signal from the image sensor A first process of receiving a subject and obtaining a subject image; A second process of analyzing the subject image and outputting a control signal for moving the position of the image sensor; And a third process of adjusting the at least one of six axes of the image sensor by driving the motor according to the control signal.

The terms used in the present invention are described as follows.

(1) An image sensor is an apparatus or electronic component that detects subject information and converts it into an electric video signal, and can be roughly divided into an imaging tube and a solid state image sensor. The former includes a beacon and plum beacon, and the latter includes a metal oxide semiconductor (MOS) and a charge coupled device (CCD). Used for televisions, cameras, etc., shooting a three-dimensional or flat subject with a lens.

(2) The image processing chart serves as a subject as an analysis tool for automatically adjusting the six axes of the image sensor in the present invention. The six axes are adjusted by analyzing the position and resolution of the pattern drawn on the image processing chart.

The above objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like numbers refer to like elements throughout. In addition, when it is determined that the detailed description of the known function or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

2 is a block diagram of an image sensor 6-axis adjusting system according to a preferred embodiment of the present invention.

Referring to Figure 2 describes a preferred embodiment of the image sensor 6-axis adjustment system according to the present invention.

The image sensor 6-axis adjustment system according to a preferred embodiment of the present invention, the lens barrel 110, the image sensor 120, the image processing chart 200, the image acquisition unit 230, the computer 240, the motor driver And a six-axis adjusting device 260. In addition, the computer 240 includes a control unit 241, a memory 243, and a monitor 245.

The image sensor 120 converts image information of the image processing chart 200 received through the lens barrel 110 into an electrical signal. The image acquisition unit 230 includes an image signal processor (ISP) to acquire an image having an appropriate resolution. The six-axis adjusting device 260 is a device that is physically connected to the image sensor 120 can move the position of the image sensor in each of the six axes. Preferably, the six-axis adjusting device 260 is configured to include a motor. More preferably, the six-axis adjusting device 260 is configured to include a stepping motor. The motor driver 250 is a device composed of an electric circuit for driving the six-axis adjusting device 260 according to the control signal output from the computer 240. The reference chart for image analysis is stored in the memory 243. The user of the image sensor 6-axis adjustment system according to the present invention can observe or control the process of adjusting the 6-axis of the image sensor through the monitor 245.

The image acquisition unit 230 receives an image signal from the image sensor 120 to obtain an image of the image processing chart 200. Here, the image acquisition unit 230 may convert the obtained image to an appropriate resolution. In particular, when the image input from the image sensor 120 is a high resolution, real-time processing is not possible due to a problem of processing speed, and when converted to too low resolution, objectivity of the image processing judgment may be lacked, so converting to an appropriate resolution It is important. Preferably, the resolution is converted to a resolution of about 640 × 480 and transmitted to the controller 241.

The control unit 241 outputs a control signal for moving the position of the image sensor 120 by analyzing an image of the image processing chart 200 received from the image acquisition unit 230. The control signal is for adjusting the six axes of the image sensor 120, respectively. Preferably, the z axis is adjusted first and the remaining axes are adjusted. An image analysis method and process of the image processing chart 200 will be described in detail below. 3 is a diagram illustrating an example of an image processing chart. The image processing chart 200 is photographed and stored in the memory 243 as a reference chart for comparison and analysis.

The motor driver 250 moves the position of the image sensor 120 by driving the six-axis adjusting device 260 in response to a control signal received from the controller 241.

Referring to the six-axis adjustment method of the image sensor according to the present invention. In order to process the image, the image must be clearly displayed. Therefore, it is preferable to adjust the remaining axes after adjusting the z axis. The z-axis adjustment process will be described in turn. The image processing chart 200 is photographed and stored in the memory 243 as a reference chart for comparison and analysis.

4 is a flowchart illustrating an embodiment of a z-axis adjusting process in the image sensor 6-axis adjusting method according to the present invention.

5 is a side view when the z-axis is adjusted.

Referring to Figures 4 and 5 will be described a preferred embodiment of the z-axis adjustment process in the image sensor 6-axis adjustment method according to the present invention. Here, the position of the lens is assumed to be fixed [S400].

First, the image acquisition unit 230 receives a signal from the image sensor 120 to obtain an image of the image processing chart 200 [S410].

Thereafter, the acquired image is analyzed to determine whether the focus of the lens is located on the surface of the image sensor 120 [S420]. When the image sensor 120 is positioned at the focal point of the lens, the high frequency component of the acquired image is maximized. As a method for finding the maximum point, MCS (Mountain Climbing Servo), which is mainly used in an auto focusing algorithm, is used. ) Can be used. The MCS method is based on the distribution curve of the Focus-Value (FV), which is similar to the shape of the mount. The FV refers to the energy of the high frequency components appearing in the image at the moving position of the lens or the image sensor, and refers to the sum of the high frequency components obtained by the high frequency extraction function. Preferably, since the adjustment for the remaining axes has not been made yet, the high frequency component extraction is performed only at the center of the acquired image. Extracting high frequency components only in the center of the image has the advantage of increasing the computational speed.

Then, if the focus of the lens is not located on the surface of the image sensor 120, and outputs a control signal for moving the image sensor 120 in the direction (z axis) coinciding with the central axis of the lens [S430] .

Thereafter, the six-axis adjusting device 260 is driven according to the control signal to move the z-axis of the image sensor 120 [S440].

As described above, when the high frequency component is extracted from the input image, the image sensor is repeatedly moved, and when the high frequency component threshold of the preset value is reached, the z axis is found and the remaining axis is adjusted. Passing In FIG. 5, the image sensor 120 moves from position 120a to position 120b to find the focal point 300 of the lens.

6 is a flowchart illustrating an embodiment of an x-axis and y-axis adjusting process in the image sensor 6-axis adjusting method according to the present invention.

7 is a perspective view (a) and a front view (b) when the x-axis and the y-axis are adjusted.

Referring to FIGS. 6 and 7, a preferred embodiment of the x-axis and y-axis adjusting process in the image sensor 6-axis adjusting method according to the present invention is as follows. Preferably, it is assumed that the z-axis is adjusted.

First, the image acquisition unit 230 receives a signal from the image sensor 120 to obtain an image of the image processing chart 200 [S600].

Thereafter, the distance between the center of the acquired image and the center of the reference chart is measured [S610]. The reason for the distance measurement is to determine how far the center of the image sensor 120 is from the central axis of the lens and to correct it. The distance measurement uses a vector to know the direction to be adjusted. That is, by measuring the vector from the center point of the reference chart to the center point of the acquired image, the correction direction and the correction distance of the x-axis and the y-axis can be known. In this case, the center point is not necessarily a reference point, and a vector from the acquired image to a point at the same position may be determined by determining an arbitrary point of the reference chart as a reference point and using this reference point as a starting point.

Thereafter, it is determined whether the measured distance is within the error range [S620], and if it is not within the error range, a control signal for moving the x-axis and the y-axis is output [S630].

Thereafter, the six-axis adjusting device 260 is driven according to the control signal to move the x-axis and the y-axis of the image sensor 120 [S640]. In FIG. 7, the position of the image sensor 120 is moved (120c? 120d) to adjust the x and y axes. Also in the x-axis and y-axis adjustment process, it is preferable to repeat the steps until the measured distance is within a certain error range. When the center of the image (the point where the 310a and 310b meet) of the image for the chart 200 is located at the center of the reference chart, the x-axis and the y-axis are corrected.

8 is a flowchart illustrating an embodiment of a c-axis adjusting process in the image sensor 6-axis adjusting method according to the present invention.

9 is a perspective view (a) and a front view (b) when the c-axis is adjusted.

Referring to Figures 8 and 9 will be described a preferred embodiment of the c-axis adjustment process in the image sensor 6-axis adjustment method according to the present invention. Preferably, it is assumed that the z-axis is adjusted.

First, the image acquisition unit 230 receives a signal from the image sensor 120 to obtain an image of the image processing chart 200 [S800].

Thereafter, it is determined whether the corner pattern of the acquired image and the corner pattern of the reference chart overlap [S810]. Here, as an example of the determination criteria, an angle to be adjusted may be calculated by measuring an angle formed between the edge pattern of the obtained image and the corner pattern of the reference chart. In FIG. 3, which shows an example of the image processing chart 200, 320a, 320b, 320c, and 320d each represent a corner fringe.

Thereafter, when the result of the determination does not overlap, a control signal for yawing operation (c-axis movement) of the image sensor 120 is output (S820).

Thereafter, the six-axis adjusting device 260 is driven according to the control signal to move the c-axis of the image sensor 120 [S830]. In FIG. 9, the position of the image sensor 120 is moved (120e → 120f) to adjust the c-axis. Even in the c-axis adjustment process, it is preferable to repeat the above steps until the measurement value by a certain criterion such as the measured angle falls within a certain error range. By the c-axis adjustment, the front view of the image sensor 120 is not inclined.

10 is a flowchart illustrating an embodiment of an a-axis and b-axis adjustment process in the image sensor 6-axis adjustment method according to the present invention.

11 is a side view when the a-axis is adjusted.

12 is a plan view when the b-axis is adjusted.

A preferred embodiment of the a-axis and b-axis adjustment process in the image sensor 6-axis adjustment method according to the present invention with reference to Figure 10 to 12 as follows. Preferably, it is assumed that the z-axis is adjusted.

First, the image acquisition unit 230 receives a signal from the image sensor 120 to obtain an image of the image processing chart 200 [S1000].

Thereafter, it is determined whether the resolutions of the patterns on the upper, lower, left, and right sides of the acquired image coincide with each other [S1010]. In FIG. 3 showing an example of the image processing chart 200, 330a, 330c, 330d, and 330b represent top, bottom, left, and right patterns, respectively. In the a-axis and b-axis adjustment process, only the patterns on the upper, lower, left, and right sides of the acquired image are compared with each other, even if they are not compared with the reference chart, or the resolution of each pattern is compared with the resolution of the pattern corresponding to the same position on the reference chart. You can also compare. In addition, when the z-axis is adjusted, the resolution 300 of the pattern at the center of the acquired image may be compared with the resolution of the pattern at the top, bottom, left, and right sides.

Thereafter, when the resolutions do not coincide with each other, a control signal for rolling the image sensor 120 (a-axis movement) or pitch operation (b-axis movement) is output (S1020). For example, if the resolution of the pattern on the top and bottom and the resolution of the pattern 300 in the center do not match, the control signal for roll operation (a-axis movement) is output, and the resolution and center of the pattern on the left and right are displayed. If the resolution of the pattern 300 does not match, a control signal for pitch operation (b-axis movement) is output.

Thereafter, the six-axis adjusting device 260 is driven according to the control signal to move the a-axis or the b-axis of the image sensor 120 [S1030]. In FIG. 11, the position of the image sensor 120 is moved (120g → 120h) to adjust the a-axis. In FIG. 12, the position of the image sensor 120 is moved (120i →) to adjust the b-axis. 120j). In the a-axis and b-axis adjustment process, it is preferable to repeat the above steps until the measurement value according to a certain criterion such as the measured resolution falls within a certain error range. By adjusting the a-axis and the b-axis, the center axis of the lens and the surface of the image sensor 120 form 90 degrees, or right angles.

When the six axes of the image sensor 120 are optimized through the above process, the lens assembly is terminated by mounting the image sensor 120 to the lens module using an adhesive at the position.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The effects of the image sensor 6-axis adjustment system and method according to the present invention described above are as follows.

First, according to the present invention, an optimal image sensor position can be found without excluding a subjective judgment of a human in the assembly process of a camera lens module.

Second, according to the present invention, the assembly time of the camera lens module can be shortened by automating 6-axis adjustment of the image sensor.

Third, according to the present invention, the quality difference between the products can be minimized by the automation of the six-axis adjustment of the image sensor, and it is possible to provide a criterion for discriminating between good and bad after assembly.

Claims (30)

In manufacturing a camera lens module having a lens and an image sensor, a system for automatically adjusting the six axes of the image sensor, A motor for adjusting the six axes by moving the position of the image sensor; An image acquisition unit receiving a signal from the image sensor to obtain an image of a subject; A computer including a control unit which analyzes the subject image received from the image acquisition unit and outputs a control signal for moving the position of the image sensor; And A motor driver for driving the motor in response to the control signal; Image sensor 6 axis adjustment system. The method of claim 1, wherein the image acquisition unit, The image sensor 6-axis adjustment system, characterized in that for converting the image obtained from the image sensor to a predetermined low resolution to pass to the controller. The method of claim 1, wherein the control signal, 6-axis adjustment system for the image sensor, characterized in that for adjusting each of the six axes of the image sensor. The method of claim 3, wherein the control signal, And position the focal point of the lens on the surface of the image sensor. The method of claim 4, wherein the control signal, And if the focus of the lens is not located on the surface of the image sensor, moving the image sensor in a direction coinciding with the central axis of the lens using an auto focusing algorithm. The method of claim 5, wherein the auto focus algorithm, Image sensor 6-axis adjustment system, characterized in that MCS (Mountain Climbing Servo). The method of claim 3, wherein the computer, A memory for storing a reference chart for analyzing the subject image; Image sensor 6-axis adjustment system characterized in that it further comprises. The method of claim 7, wherein the control signal, And an image sensor 6-axis adjustment system for positioning the center of the image sensor on the center axis of the lens. The method of claim 8, wherein the control signal, When the center of the subject image and the center of the reference chart are not matched with each other, the image sensor is moved upward, downward, left, and right in a direction perpendicular to the central axis of the lens. 6-axis adjustment system, characterized in that for moving to). The method of claim 9, wherein the comparison between the subject image and the reference chart comprises: The image sensor 6-axis adjustment system, characterized in that made using a vector as a starting point of any reference point in the reference chart. The method of claim 7, wherein the control signal, And a six-axis adjustment system for operating the image sensor. The method of claim 11, wherein the control signal, And the image sensor is operated with respect to the center axis of the lens when the subject image is inclined compared to the reference chart. The method of claim 12, wherein the comparison between the subject image and the reference chart comprises: And an edge of the reference chart and an edge of the subject image are located at the same position. The method of claim 7, wherein the control signal, And a roll operation or a pitch operation of the image sensor. The method of claim 14, wherein the control signal, If the resolutions of the upper, lower, left, and right of the subject image do not match, roll the image sensor according to a result of comparing the subject image with the reference chart. Image sensor 6-axis adjustment system, characterized in that the roll operation or the pitch operation. The method of claim 15, wherein the comparison between the subject image and the reference chart comprises: And the resolution of the pattern at the center of the reference chart and the resolution of the pattern at the top, bottom, left, and right of the subject image. Image sensor 6-axis adjustment system. The method of claim 1, wherein the motor, Image sensor 6-axis adjustment system characterized in that the stepping motor. In manufacturing a camera lens module having a lens and an image sensor using a computer system capable of driving a motor, A first step of obtaining a subject image by receiving a signal from the image sensor; A second process of analyzing the subject image and outputting a control signal for moving the position of the image sensor; And A third process of adjusting at least one of the six axes of the image sensor by driving the motor according to the control signal; 6-axis adjustment method of the image sensor comprises a. The method of claim 18, wherein the second process, And a control signal for positioning the focus of the lens on the surface of the image sensor. The method of claim 19, wherein the second process, If the focus of the lens is not located on the surface of the image sensor, an image sensor, characterized in that for outputting a control signal for moving the image sensor in a direction coinciding with the central axis of the lens using an automatic focusing algorithm. 6-axis adjustment method. The method of claim 20, wherein the auto focus algorithm, Image sensor 6-axis adjustment method characterized in that the MCS (Mountain Climbing Servo) method. The method of claim 18, wherein the second process, And outputting a control signal for positioning the center of the image sensor on the center axis of the lens. The method of claim 22, wherein the second process, When the center of the subject image and the center of the reference chart are not matched with each other, the image sensor is moved upward, downward, left, right, and right in a direction perpendicular to the central axis of the lens. 6) An image sensor 6-axis adjusting method characterized by outputting a control signal to move. The method of claim 23, wherein the comparison between the subject image and the reference chart comprises: The six-axis adjustment method of the image sensor, characterized in that using a vector having a reference point as a starting point in the reference chart. The method of claim 18, wherein the second process, And outputting a control signal for operating the image sensor with respect to the center axis of the lens when the subject image is inclined compared to the reference chart. The method of claim 25, wherein the comparison between the subject image and the reference chart comprises: And an edge of the reference chart and an edge of the subject image are located at the same position. The method of claim 18, wherein the second process, And outputting a control signal for rolling or pitching the image sensor. The method of claim 27, wherein the second process, If the resolutions of the upper, lower, left, and right of the subject image do not match, roll the image sensor according to a result of comparing the subject image with the reference chart. (roll) 6-axis adjustment method of the image sensor, characterized in that for outputting a control signal for operating the pitch (pitch). The method of claim 28, wherein the comparison between the subject image and the reference chart comprises: And the resolution of the pattern at the center of the reference chart and the resolution of the pattern at the top, bottom, left, and right of the subject image. How to adjust 6-axis image sensor. 30. The method of claim 18, wherein the first to third processes, 6-axis adjustment method of the image sensor, characterized in that it is repeated until the predetermined error range is satisfied.

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