CN103149789A - Image modulation transfer function (MTF) evaluation-based module motor curve testing method - Google Patents

Image modulation transfer function (MTF) evaluation-based module motor curve testing method Download PDF

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Publication number
CN103149789A
CN103149789A CN201310063935XA CN201310063935A CN103149789A CN 103149789 A CN103149789 A CN 103149789A CN 201310063935X A CN201310063935X A CN 201310063935XA CN 201310063935 A CN201310063935 A CN 201310063935A CN 103149789 A CN103149789 A CN 103149789A
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China
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motor
image
curve
module
testing
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CN201310063935XA
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CN103149789B (en
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丁亮
张宝忠
张扣文
王刚
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宁波舜宇光电信息有限公司
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Abstract

The invention provides an image modulation transfer function (MTF) evaluation-based module motor curve testing method. An MTF capable of reflecting a defocusing change condition of a lens and testing the consistency of motor characteristics is used as a definition calculation function, MTFs of different positions of a motor are analyzed according to a motor curve fitted by the MTFs, the kinetic characteristics of the motor are judged, and when the motor curve is tested, the positions of the highest points of the motor curve in four corners of a displayed image are simultaneously found, the positions of the four corners are calculated to obtain focal length differences of the four corners, a tilting height difference of the lens and the surface of a sensor is judged, and a tilting angle is calculated. According to the motor curve testing scheme applied by the invention, an MTF testing target and image detection equipment are used for effectively detecting the motor characteristics of a module and bad conditions of tilting of the motor, so that the quality of the product is ensured.

Description

Estimate the method for testing of module motor curve based on image M TF

Technical field

The present invention relates to mobile phone cam module motor curve test method, especially relate to the technical method of the AF mobile phone cam module motor curve test of estimating based on image M TF.

Background technology

At present along with AF(focuses automatically) widespread use of mobile phone cam, the assembling inclination and the motor abnormal problem that cause due to reasons such as processing procedure and motor supplied materials often occur.How this defective products is detected the key of guaranteeing product quality with being.Classic method is to test the dynamic tilt of motor curve and motor with the mode of laser ranging.The dynamic tilt of motor can not the complete reaction camera lens and sensor between inclination, therefore, the method for studying the inclination between a kind of accurately detector lens and sensor and can testing the motor curve simultaneously will be particularly important.

Summary of the invention

The present invention is a kind of novel AF mobile phone cam module motor curve test method based on image M TF evaluation, test the performance of module motor with the method, the accurately inclination between detector lens and sensor and can reflect the performance of testing motor simultaneously of described method, described a kind of method of testing of estimating module motor curve based on image M TF comprises the following steps:

1) select target and back light, utilize the adjustment height support to adjust target to the distance of Camera Test module, the focal position of the corresponding test of described distance module, be the focal position of motor when running to half stroke to positive dirction of test module, the Camera Test module be placed on the test position of graphic transmission equipment;

2) open the back light of test chart top, start graphic transmission equipment, the test module is carried out the initialization setting, the target image that described test module is taken is square, then drive the motor operation of Camera Test module, described graphic transmission equipment will be tested the target image transmitting of module shooting to computing machine;

3) fixed step size is set, choose the image that positive and negative two traffic directions of motor all run to the test module when setting step-length, and the mtf value at computed image center, draw the step-length of positive and negative two traffic directions of motor and the relation curve of picture centre MTF, be similar to normal distribution curve according to the motor class of a curve of picture centre MTF match;

4) aligning too distribution curve analyzes, the two ends lifting position of described normal distribution curve is respectively enable position and the stop position of motor operation direction, the linearity of the smoothness of described curve reflection motor operation, the difference of the normal distribution curve peak position of positive and negative two traffic directions of motor is that motor is sluggish.

Wherein, the image of described Computer display is 1/8th sizes of the target image that photographs of test module.

When testing, the method for testing step at the angle of inclination of motor is as described below:

1) in the operation test of motor positive dirction, draw simultaneously the mtf value at square-shaped image four angles and the curve of motor step-length, four curves of drafting are normal distribution curve;

2) find out four peak positions of four curves, the vergence direction of motor is the overturning angle from first peak of the angle at last peak place place, the horizontal ordinate difference of first peak and last peak position is the difference of motor step number, in the identical characteristic of the focal length of same field, can calculate the angle of inclination of motor according to camera lens.

The tangent value at motor angle of inclination is the ratio of the actual physics distance at the inclined height of motor and image two angles, and the inclined height of described motor can be multiplied each other by the operation slope of the difference of motor step number and motor and draw.

Further, the brightness stability of described back light, the brightness of back light panel is even.

The size of described target and light source can be full of the whole image that the test module is taken.

The motor curve testing scheme that the present invention uses, by using the MTF(modulation transfer function) test chart and image detecting apparatus, change the mode of use laser testing in the past, effectively detected the bad of the motor of module and motor inclination aspect, guaranteed the quality of product.Use this method of testing, the bad product of this respect can be detected.

Description of drawings

Fig. 1 is the testing apparatus schematic diagram of embodiments of the invention;

Fig. 2 is the preparation flow process of motor curve test in embodiment;

Fig. 3 is test flow chart in embodiment;

Fig. 4 is according to the motor curve synoptic diagram of picture centre MTF match in embodiment;

Fig. 5 is the peak position view of the motor curve at four angles of image in embodiment;

Fig. 6 is the schematic diagram at motor angle of inclination.

Embodiment

Problem to be solved by this invention is AF mobile phone module motor abnormal products is detected, and a kind of motor curve measuring technology scheme of estimating based on image M TF is provided.Foundation is for fixing object distance, the defocusing amount that changes camera lens can change the sharpness of module imaging, by selecting suitable sharpness computation function, can substitute laser ranging, the consistance that is used for the test motor characteristics is such as starting current, stop electric current, the linearity, sluggishness etc.In this programme, utilize the MTF evaluation of image definition computing function to substitute traditional laser testing, the MTF that adopts image is because this function anti-interference is good, and can reflect accurately the out of focus situation of camera lens, thereby can reasonable evaluation motor curve characteristic.

The operation of motor is mainly displacement, the variation of displacement is the variation of focal length in the performance of camera lens, and the embodiment of the variation of focal length on image is the variation of image definition, so situation of change with MTF, can indirectly test the change in displacement situation of motor, change camera lens with respect to the change in displacement of focal position by the relative position that changes motor, then by calculating motor operation at the mtf value of diverse location image, just can judge the ruuning situation of motor.

As shown in Figure 1, the parts that described method of testing is utilized have: adjustment height support 1, target 5, back light 4, image capture device 3, test module 2.

as shown in Figure 2, select target 5 and back light 4, utilize adjustment height support 1 to adjust target 5 to the distance of Camera Test module 2, described distance can be according to camera lens depth-of-field guide quick-setting, make test module 2 focal position just in time be in the position that the motor positive dirction runs to half stroke, the size of described target 5 and back light 4 can be full of the whole image that the test module is taken, the brightness stability of described back light 4, evenly, select the stable image capture device 3 of transmission, the motor that need to can accurately control simultaneously module in test drives, make motor to move according to preset requirement, then Camera Test module 2 is placed on the test position of graphic transmission equipment 3, and open the back light of test chart top, test.

Described test flow chart as shown in Figure 3, the initialization test module, motor is parked on initialized step number, the mark domain that described test module photographs similarly is square, because the figure of the sensor transmissions of test module is square, described image is transferred to computing machine through graphic transmission equipment, and the image of described Computer display is 1/8th sizes of the target image that photographs of test module, and this ratio also can be adjusted.

In the time of on the initialized step number of motor, the image that shows is unsharp, operation along with the motor positive dirction, image will be from unintelligible to clear, be motor positive dirction when running to half stroke in the time of the most clearly, the image on this moment target is on the focal length of test module, when motor continues operation, on the focal length of test module, image is not from clear to unintelligible for image on target.

Motor operation is to move according to the fixed step size of setting, and obtains the image of place step-length and shows on computers image, calculates mtf value and real-time rendering curve, in order to finish all mtf values of post analysis and show test results at the test stroke.

According to characteristics linear between motor displacement and drive current, the relation that the MTF of module and optical image distance present is the normal distribution curve centered by focal length.According to above 2 points, can derive, use the motor class of a curve of MTF match to be similar to a normal distribution curve.

As shown in Figure 4, the curve of drawing during the positive and negative both direction operation of motor overlaps, motor is when moving to positive dirction, enable position is that c and stop position are b, motor is to reverse direction operation the time, and enable position is that b and stop position are c, and the process the during operation of motor positive dirction has been divided into 78 equal portions, and during reverse direction operation, run to when setting step-length and positive dirction has same mtf value.Can judge the linearity of motor operation by the smoothness of curve, line smoothing, the motor wire performance enough reaches requirement.The motor difference of the curve peak position a of both direction operation back and forth is that motor is sluggish, and it is sluggish in full accord with standard that curve overlaps explanation.

Further, in conjunction with the lens optical characteristic, can directly test out the degree of tilt between AF process camera lens and sensor, the degree of tilt of motor is exactly the degree of tilt of sensor.When test curve, draw simultaneously the mtf value at square-shaped image four angles and the curve of motor one direction step-length, four curves drawing are also normal distribution curve, find out four peak positions of four curves, and the vergence direction of motor is the overturning angle from first peak of the angle at last peak place place, in Fig. 5, upper left corner curve is m1, and upper right corner curve is m2, and lower left corner curve is m3, lower right corner curve is m4, and motor is from the lower left corner to the upper right overturning angle.

In Fig. 5, the initialized step number of motor is 180step, the horizontal ordinate difference of first peak and last peak position is the difference of motor step number, according to camera lens in the identical characteristic of the focal length of same field, can calculate the angle of inclination of motor, upper left corner m1 arrives focal position prior to lower right corner m4, and differs the 25step distance, can determine that according to experimental test motor specification the motor slope is 0.54 μ m/step, therefore can calculate the poor S of inclined height is 13.5 μ m.As shown in Figure 6, according to design, can determine the actual physics distance L at two angles of image, finally calculate tilt angle theta=arctan(13.5/L), described angle of inclination is exactly the angle of inclination of 7 of camera lens 6 and sensors.

The present invention has changed the mode of use laser testing in the past by using the MTF test, has effectively detected the bad of the motor of module and inclination aspect, has guaranteed the quality of product.Use this method of testing, the bad product of this respect can be detected.

Claims (6)

1. a method of testing of estimating module motor curve based on image M TF, comprise the following steps:
1) select target and back light, utilize the adjustment height support to adjust target to the distance of Camera Test module, the focal position of the corresponding test of described distance module, be the focal position of motor when running to half stroke to positive dirction of test module, the Camera Test module be placed on the test position of graphic transmission equipment;
2) open the back light of test chart top, start graphic transmission equipment, the test module is carried out the initialization setting, the target image that described test module is taken is square, then drive the motor operation of Camera Test module, described graphic transmission equipment will be tested the target image transmitting of module shooting to computing machine;
3) fixed step size is set, choose the image that positive and negative two traffic directions of motor all run to the test module when setting step-length, and the mtf value at computed image center, draw the step-length of positive and negative two traffic directions of motor and the relation curve of picture centre MTF, be similar to normal distribution curve according to the motor class of a curve of picture centre MTF match;
4) aligning too distribution curve analyzes, the two ends lifting position of described normal distribution curve is respectively enable position and the stop position of motor operation direction, the linearity of the smoothness of described curve reflection motor operation, the difference of the normal distribution curve peak position of positive and negative two traffic directions of motor is that motor is sluggish.
2. the method for testing of estimating module motor curve based on image M TF according to claim 1, it is characterized in that: the method for testing step at the angle of inclination of motor is as described below:
1) in the operation test of motor positive dirction, draw simultaneously the mtf value at square-shaped image four angles and the curve of motor step-length, four curves of drafting are normal distribution curve;
2) find out four peak positions of four curves, the vergence direction of motor is the overturning angle from first peak of the angle at last peak place place, the horizontal ordinate difference of first peak and last peak position is the difference of motor step number, in the identical characteristic of the focal length of same field, can calculate the angle of inclination of motor according to camera lens.
3. the method for testing of estimating module motor curve based on image M TF according to claim 1, is characterized in that: step 2) in, the image of described Computer display is 1/8th sizes of the target image that photographs of test module.
4. the method for testing of estimating module motor curve based on image M TF according to claim 2, it is characterized in that: the tangent value at motor angle of inclination is the ratio of the actual physics distance at the inclined height of motor and image two angles, and the inclined height of described motor can be multiplied each other by the operation slope of the difference of motor step number and motor and draw.
5. the method for testing of estimating module motor curve based on image M TF according to claim 1, it is characterized in that: the brightness stability of described back light, the brightness of back light panel is even.
6. the method for testing of estimating module motor curve based on image M TF according to claim 1, it is characterized in that: the size of described target and light source can be full of the whole image that the test module is taken.
CN201310063935.XA 2013-02-28 2013-02-28 The method of testing of module motor curve is evaluated based on image MTF CN103149789B (en)

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CN103837828A (en) * 2014-03-27 2014-06-04 广东欧珀移动通信有限公司 Travel curve test method and system of camera-shooting mode motor and mobile terminal
CN104219428A (en) * 2014-08-21 2014-12-17 深圳市金立通信设备有限公司 Camera installation device
CN104219427A (en) * 2014-08-21 2014-12-17 深圳市金立通信设备有限公司 Camera installation method
CN104683587A (en) * 2015-03-09 2015-06-03 深圳市欧珀通信软件有限公司 Mobile terminal, camera focusing method thereof and camera focusing device thereof
CN105025290A (en) * 2014-04-23 2015-11-04 宁波舜宇光电信息有限公司 Method for automatically adjusting inclination between image photographing module group sensor and lens
CN105744266A (en) * 2016-03-25 2016-07-06 宁波舜宇光电信息有限公司 Inclination measurement system and method of camera module
CN105787947A (en) * 2016-03-22 2016-07-20 歌尔声学股份有限公司 Voice coil motor stroke calibration method and device and test fixture
CN107403453A (en) * 2017-07-25 2017-11-28 歌尔股份有限公司 Adjusting process and device based on photoelectricity module
CN107483921A (en) * 2017-08-18 2017-12-15 信利光电股份有限公司 A kind of method and device for the linearity for judging motor
CN107656418A (en) * 2016-07-26 2018-02-02 宁波舜宇光电信息有限公司 The test of adjustable focus camera module inclined light shaft and computational methods
CN107861063A (en) * 2017-12-14 2018-03-30 信利光电股份有限公司 A kind of motor testing apparatus
CN107920246A (en) * 2017-12-28 2018-04-17 广东欧珀移动通信有限公司 The gradient test method and device of camera module
CN108012145A (en) * 2017-12-14 2018-05-08 信利光电股份有限公司 Solution method, system and the equipment of foreign matter are arranged at camera module motor bottom
CN108107362A (en) * 2017-12-26 2018-06-01 信利光电股份有限公司 A kind of characteristic quadratic slope determination methods of voice coil motor, device and equipment
CN108169868A (en) * 2017-12-26 2018-06-15 信利光电股份有限公司 A kind of characteristic quadratic slope judgment method of voice coil motor, device and equipment
CN108737815A (en) * 2018-04-13 2018-11-02 深圳怡化电脑股份有限公司 A kind of quality determining method and system of imaging sensor
CN108989791A (en) * 2018-07-11 2018-12-11 昆山丘钛微电子科技有限公司 A kind of linear detection method of motor, device and computer readable storage medium
CN110855856A (en) * 2018-08-21 2020-02-28 宁波舜宇光电信息有限公司 Assembling method of multi-group optical lens based on motor optical assembly

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CN103837828A (en) * 2014-03-27 2014-06-04 广东欧珀移动通信有限公司 Travel curve test method and system of camera-shooting mode motor and mobile terminal
CN105025290A (en) * 2014-04-23 2015-11-04 宁波舜宇光电信息有限公司 Method for automatically adjusting inclination between image photographing module group sensor and lens
CN104219428A (en) * 2014-08-21 2014-12-17 深圳市金立通信设备有限公司 Camera installation device
CN104219427A (en) * 2014-08-21 2014-12-17 深圳市金立通信设备有限公司 Camera installation method
CN104219428B (en) * 2014-08-21 2019-04-26 深圳市金立通信设备有限公司 A kind of camera mounting device
CN104683587A (en) * 2015-03-09 2015-06-03 深圳市欧珀通信软件有限公司 Mobile terminal, camera focusing method thereof and camera focusing device thereof
CN105787947A (en) * 2016-03-22 2016-07-20 歌尔声学股份有限公司 Voice coil motor stroke calibration method and device and test fixture
CN105787947B (en) * 2016-03-22 2018-05-01 歌尔股份有限公司 Demarcate the method, apparatus and measurement jig of voice coil motor stroke
WO2017162201A1 (en) * 2016-03-25 2017-09-28 宁波舜宇光电信息有限公司 Inclination measurement system for photographing module and measurement method
CN105744266A (en) * 2016-03-25 2016-07-06 宁波舜宇光电信息有限公司 Inclination measurement system and method of camera module
CN107656418A (en) * 2016-07-26 2018-02-02 宁波舜宇光电信息有限公司 The test of adjustable focus camera module inclined light shaft and computational methods
CN107403453A (en) * 2017-07-25 2017-11-28 歌尔股份有限公司 Adjusting process and device based on photoelectricity module
CN107403453B (en) * 2017-07-25 2020-11-17 歌尔光学科技有限公司 Adjusting method and device based on photoelectric module
CN107483921A (en) * 2017-08-18 2017-12-15 信利光电股份有限公司 A kind of method and device for the linearity for judging motor
CN108012145A (en) * 2017-12-14 2018-05-08 信利光电股份有限公司 Solution method, system and the equipment of foreign matter are arranged at camera module motor bottom
CN107861063A (en) * 2017-12-14 2018-03-30 信利光电股份有限公司 A kind of motor testing apparatus
CN108107362A (en) * 2017-12-26 2018-06-01 信利光电股份有限公司 A kind of characteristic quadratic slope determination methods of voice coil motor, device and equipment
CN108169868A (en) * 2017-12-26 2018-06-15 信利光电股份有限公司 A kind of characteristic quadratic slope judgment method of voice coil motor, device and equipment
CN107920246B (en) * 2017-12-28 2019-10-25 Oppo广东移动通信有限公司 The gradient test method and device of camera module
WO2019128534A1 (en) * 2017-12-28 2019-07-04 Oppo广东移动通信有限公司 Degree of incline test method and apparatus for camera module, and storage medium and electronic device
CN107920246A (en) * 2017-12-28 2018-04-17 广东欧珀移动通信有限公司 The gradient test method and device of camera module
CN108737815B (en) * 2018-04-13 2019-12-10 深圳怡化电脑股份有限公司 Quality detection method and system of image sensor
CN108737815A (en) * 2018-04-13 2018-11-02 深圳怡化电脑股份有限公司 A kind of quality determining method and system of imaging sensor
CN108989791A (en) * 2018-07-11 2018-12-11 昆山丘钛微电子科技有限公司 A kind of linear detection method of motor, device and computer readable storage medium
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CN110855856A (en) * 2018-08-21 2020-02-28 宁波舜宇光电信息有限公司 Assembling method of multi-group optical lens based on motor optical assembly

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