DMD编码哈达玛变换高灵敏成像
High sensitivity imaging based on DMD coding Hadamard Transform
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摘要: 为了增强探测器在微弱光信号条件下的成像质量,提出了一种利用哈达玛变换(Hadamard Transform,HT)实现高灵敏探测的成像方法。基于探测器噪声独立于信号,且每次测量噪声也相互独立的假设,分析了在哈达玛编码成像与经典成像中,噪声对图像信噪比的影响。推导出编码成像的信噪比提升与编码模板长度n有关,约为经典成像信噪比的n/2 倍。同时采用分区编码的方式,减小了高分辨率图像的编码时间。实验结果表明,与经典成像方式相比,采用分区编码的哈达玛变换成像方法明显的提高了图像的信噪比,同时可以在高分辨率图像条件下,缩短编码时间。Abstract: In order to enhance the image quality of the detector under the condition of Low Level Light(LLL) signal, a method of high sensitivity imaging based on Digital Micromirror Device(DMD) coding Hadamard Transform was proposed. On the basis of the assumptions that the noise of the detector and the signal as well as the noise measured each time are both independent, the influence of the noise to the SNR was analyzed in both HT coding imaging and classical imaging. The result was deduced that the improvement of SNR was related to the length n of coding templates in coding imaging, and the value was n/2 times of that in classic imaging. In order to reduce the encoding time of the image, the partitions coding method was applied. Results show that, compared with classical imaging modalities, the use of partitions coding Hadamard transform imaging significantly improves the signal to noise ratio of the image, while the coding time of high-resolution images is shortened.