Optical testing is constantly evolving, necessitating higher lateral resolution in interferometry. Achieving high resolution leads to longer processing times, significantly impacting testing efficiency. The unwrapping phase algorithm is crucial in interferometry, but its complex calculations can impede efficiency improvements. There are two types of algorithms for the unwrapping phase: path-dependent and path-independent. Path-dependent algorithms tend to be more efficient, and thus, we have chosen to utilize the accelerated path-dependent algorithm. Among these algorithms, Goldstein's algorithm is widely applied. This study uses CPU-GPU heterogeneous computing to parallelize and accelerate the Goldstein phase unwrapping algorithm while maintaining acceptable numerical error limits. Our proposal focuses on optimizing the serial Goldstein algorithm for GPU architectures by parallelizing and enhancing three key steps: residue identification, branch cutting, and integration. Specifically, our optimization approach leverages GPU shared memory and SIMD functionality. To assess the efficiency of our proposed method, we conducted tests on the unwrapped phase image with varying pixel sizes. The results demonstrate that as the pixel size increases, the performance gain from GPU computation becomes more pronounced compared to CPU computation. Using a 4096×4096 phase diagram on the RTX3070 laptop hardware, we achieved a 60x speed increase in the overall process compared to the CPU version. Therefore, employing this algorithm with the GPU can significantly expedite the phase unwrapping process and enhance the efficiency of interferometry.
In this paper, we mainly use the basic principle of Fizeau interferometer, because Fizeau type interferometer has the advantage of common optical path, which can reduce the influence of some system errors to a certain extent, and the requirements for environmental changes are relatively low, and then use zemax optical simulation software to simulate the cat's eye position, confocal position and confocal rotation 180 degree position in the three position absolute detection method, and establish the absolute measurement model . Through the combination of simulation and simulation, it is concluded that the measurement error mainly includes tilt error, translation error and defocus error. Among them, the tilt error and translation error have negligible impact on the system measurement results, and the defocus error has a greater impact on the measurement results. Finally, the defocus error is removed by a new higher-order defocus removal method.
KEYWORDS: Fizeau interferometers, Wavefronts, Control systems design, Control systems, Switching, Optical transmission, Equipment, Wavefront errors, Visualization, Signal detection
To address the problem that the traditional multi-wavelength wavefront detection requires manual adjustment of mechanical devices and low automation, this paper proposes a multi-wavelength laser interferometer control system with the Fizeau-type interferometer principle as the background, using Visual Studio to establish the upper computer control interface on the computer and sending signals to the microcontroller through the serial port to control the interferometer. Among them, the main controls are the switching of fluorescence alignment plate in 1064nm laser, the translation drive of collimating lens within 2mm of Z-axis, the automatic adjustment of variable diaphragm and the variable adjustment of CCD. The system realizes the automatic switching of five wavelengths of the multi-wavelength laser interferometer by controlling the precision motor, which reduces the error caused by manual adjustment and improves the measurement accuracy and efficiency of the interferometer.
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