Background introduction:
In March 3rd, it received the standard reflector lens supplied by Changchun Institute of Optics, with accurate testing data. After receiving the sample, the Dalian optical detector, through the stripe detection equipment to detect and evaluate the accuracy of the sample, according to the actual results to give feedback.
Standard sample
Zygo detection result
Introduction to JIANYING optical detection equipment:
1.Hardware introduction:
Hardware composition diagram
Hardware components include:
（1）、55 inch 4K LCD TV, the distance is 0.315mm
（2）、Domestic 1 million 300 thousand pixel industrial camera with a resolution of 1280*1024, 1/2 inch CMOS chip camera
（3）、Fuji can millions of pixels industrial lens, 75mm
2.Software part introduction:
System software interface
At the beginning of the beginning of software design is mainly considered in the field of thermal lens detection, in order to meet the requirements of industrial use, in addition to the initial manual calibration, but also increased the internal position and angle automatic calibration function, for correcting position errors. At the same time, the simulation of the light spot is added to confirm the optical effect.
In the detection, due to the light and heat field requires only Slope Error, although the software is currently integrated with the surface fitting function, but the effect is generally, the main analysis from Slope Error.
The accuracy of the software is calculated as follows:
Single direction 20 thousand points of the measurement error evaluation, the unit for micro arc
Standard deviation of 0.99 micro radian, the overall standard deviation of the micro arc in the 1.40, the standard deviation of 3 times the micro arc of 4.20.
Due to the requirements of the industry in the precision of the sub - arc, the equipment can fully meet the requirements.
Actual test results of lenses:
The actual lens detection, we placed in accordance with the normal position of 10 meters, TV shows multiple sets of stripes, shooting pictures and software analysis, the results are as follows:
Horizontal and vertical fringe data
In order to make it easier to adjust the angle of the lens, we placed a soft cushion under the lens.
The test results are as follows:
Standard test results
In the standard test results above, the maximum value of the column on the right side is 20 radians (with pictures).
The test due to the edge of the error is large, affecting the overall distribution, in order to improve the accuracy of measurement results, the effects of the removal of the red edge of maximum value, the calculation of the maximum value of 20 rad and 10 rad respectively, and to have the image and vector vector arrow arrow graph representation, image capture as follows (the size of each lattice representation 0.1M):
The maximum value of 20 rad Slope error distribution (without removal of the border), the root mean square of (RAD)
The maximum value is 10 rad Slope error distribution (remove the border), the root mean square is rad 6.11
The slope error distribution and status of the standard lens can be determined through the
measurement of the above image.
Slope RMS distribution of measured surface on Zygo
Analysis and improvement of test results
Through the actual test, the measurement results are given for reference:
1、Through the lens, we have evaluated the following system error, the evaluation method using Slope RMS, the measurement accuracy of 4.2 rad.
2、In the actual measurement, the distribution of the surface roughness of the lens is generally from the inside to the outside, and there is an angular distribution in the inner periphery. Compared with the Zygo measurement, the Peak value of 15.57 rad is slightly less than Zygo of 20.2 rad, the root mean square value of 6.11 rad is also slightly less than Zygo of 6.56 rad. In general, it has a good correlation with Zygo measurement, which shows that the measured results are accurate.
3、The speed of software measurement, with high precision, accurate to the millimeter level in the measurement of the distance before and after placed on the system needs, other position and angle with the optimization methods of correction, may be appropriate to relax, the process of data acquisition in about 20s, the analysis process of 2s.
Because the accuracy of the device is still higher than that of the high-precision detection, but also by the distribution of the measured data in Figure 5, the device also has a larger room for improvement. If you need to detect this high precision lens, you can consider the following way to continue to improve the accuracy of the device:
1、Hardware improvement:
（1）、Improve the quality of the display, replace the small resolution, wide color gamut display;
（2）、Replacement of large target surface, the number of deep CCD industrial camera;
（3）、Replace high resolution lens;
（4）、The correct position of each hardware is detected.
2、Software improvement:
（1）、The distortion correction algorithm is improved, and the sub-pixel distortion correction is realized;
（2）、The software can be used to improve the algorithm, correlation method, improve the accuracy of the algorithm, noise reduction effect.
Through the above algorithm to improve the accuracy of the test is expected to be more than 1 rad.
