Research On Hadamard Transform High Sensitive Imaging System Based On DMD Coding

Compared to the conventional two-dimensional imaging techniques, the Hadamard encoding technology has the advantage of high SNR(signal to noise ratio). Even the images achieved in the faint light irradiation conditions has high SNR, However, target information is often lost in the noise under conditions of strong background noise. An appropriate mathematical model need to be established to apply the advantages that Hadamard encoding has the multi-channels to the two-dimensional imaging. Meanwhile, a targeted optical system need to be designed to realize the linear superposition of signal detection from the perspective of optical design based on the theory of Hadamard encoded. Thus, the use of Hadamard transform theory to achieve coding imaging needs to solve two problems, namely mathematical models to improve SNR and signal superposition optical system to achieve high magnification in the two-dimensional imaging based on Hadamard theory. Research work of this paper are mainly around these two issues.The basic theory of Hadamard encoding detection is elaborated, the mathematical model to realize two-dimensional imaging has been discussed under the assumption that the noise is independent of the detector signal during each measurement. The results show that the improvement of SNR in Hadamard coding imaging is relate to the length of Hadamard encoding templates n and is of that of conventional two-dimensional into the imaging signal. From the perspective of the practical applications, the best coding matrix is determined to be loop S matrix.The characteristics of parallel light passing through the plano-convex lens under the condition of narrow field is analyzed and the optical system is designed by a configuration of different focal length plano-convex. The imaging system can not only achieve the optical signal convergence with a high magnification but also minimizing energy loss at the most. It meets the demands of beam convergence capability of the imaging system and a high acquisition of automation systems is realized by using the combination of the operating mode with coding templates and detectorsBased on the above analysis of theories, an two-dimension imaging optical system of Hadamard transform is designed, and preliminary experiments are implemented. The results indicate that the imaging system can achieve a high SNR image reconstruction.