Aberration-free Image Reconstruction Method Based on CCD Array Pixel Response Function Calibration in Frequency Domain

Abstract

The invention discloses an aberration-free image reconstruction method based on CCD array pixel response function frequency domain calibration, and belongs to the technical field of detectors. A frequency domain model of pixel response functions is established, same-frequency lasers with high stability are utilized for generating sinusoidal interference fringes in a far field, fringe light fields at different spatial frequencies are acquired by changing the relative positions of the same-frequency lasers, frequency domain calibration is conducted on the pixel response functions, calibration coefficients in all orders of all the pixel response functions are acquired respectively, on the basis and in combination with a Fourier optics method, CCD imaging reconstruction is achieved, and aberration-free imaging of a CCD detector can be achieved. According to the method, the pixel frequency domain response functions can be calibrated, meanwhile, tiny offset of the relative positions of all pixels can be calibrated, reconstructed images are free of sample blurs, modulation transfer functions (MTF) approach 1, the contrast ratio is not decreased, and the aberration-free image reconstruction method has the advantages of being high in calibration accuracy and wide in application prospect.

Description

technical field [0001] The invention belongs to the technical field of calibration of optical metrology detectors, and relates to a frequency domain reconstruction method for aberration-free imaging of detectors based on frequency domain calibration of pixel response functions. Background technique [0002] The emergence of photoelectric imaging detector arrays has almost completely replaced film for its convenience in digital storage, transmission and processing, whether it is for military or civilian use. Charge Coupled Device (CCD) is one of the most commonly used detector arrays. It can convert optical images into discrete digital electrical signals, and its smallest working unit is a pixel. With the development of VLSI technology, the resolution, sensitivity, stability and other technical indicators of CCD have been greatly improved, and have been widely used in industrial inspection, machine vision, aerospace remote sensing, low-light night vision, imaging guidance , ...

AI Technical Summary

Problems solved by technology

By scanning the different pixel positions of the CCD with a focused spot (sub-micron size) close to the diffraction limit, the PRF of the measurement pixel can be discretely measured. Due to the limitation of the diffraction limit of the focusing optical system, the size of the focused spot cannot be infinitely small, so its resolution is limited. However, the scanning area of ​​this method can only reach a few pixels, the measurement range is small, and the speed is slow, which is not suitable for practical engineering applications

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