数字微镜Hadamard变换光谱仪光谱反演矩阵标定及实验

国内外对DMD空间光调制的Hadamard变换成像光谱仪做了大量的理论研究和实验验证，但这项技术的研究还不够成熟，很多问题需要进一步的研究。在这种光谱仪中每个像素点色散光谱的编码矩阵互不相同。通过比较激光编码图像灰度值的变化并结合S矩阵元素的变化规律，提出了一种光谱反演矩阵的标定方法。以七阶左移循环S矩阵为例设计编码模板，通过两组成像实验对光谱反演结果进行了验证。在第一组实验中，将一束激光波长为632.8 nm激光导入光谱仪中，光谱仪的光谱响应范围为550~680 nm，632.8 nm在第五个波段范围626~644 nm之内理论上只有波段范围为626~644 nm的第五幅光谱图像是明亮的，其余的图像没有能量分布，实际的实验结果与理论上的分析相吻合。在第二组实验中，让光谱仪对一个彩色蝴蝶模型进行成像，在反演后得到的光谱图像上提取两个测试点的光谱曲线，与用辐射度计提取的光谱特性曲线进行对比分析，实验结果表明反演所得的光谱曲线与辐射度提取的光谱特性曲线基本一致。两组光谱反演的实验结果验证了所提出的光谱反演矩阵标定方法的有效性。

Spectral recovery matrices identification and experiment of Hadamard transform spectrometer based on DMD

A great deal of theoretical research and experimental verification has been done on the DMD spatial light modulated Hadamard transform spectrometer, but the research on this technology was still immature, many problems need to be further studied. The spatial distribution of the dispersion spectrum on the DMD was different because of the different spatial positions of the pixels on the image which resulted in the different encoding matrices of the dispersion spectrum of each pixel. An identification method of spectral recovery matrix was proposed by comparing the gray values of laser-coded images and combining with the changing rules of S-matrix elements. Taking the 7-order left-shift cyclic S-matrix as an example, the results of spectral recovery were verified by two imaging experiments. In the first experiment, a laser beam of 632.8 nm was directed into the spectrometer, the spectral response range of the spectrometer was 550-680 nm, and 632.8 nm within the fifth band range from 626 nm to 644 nm. Theoretically, only the fifth spectral images with a bond range of 626-644 nm was bright, and the rest of the images have no energy distribution. The actual experimental results are in agreement with the theoretical analysis. In the second experiment, the spectrometer was used to image a color butterfly model. The spectral curves of two test points were extracted from the recovered spectral images, and compared with the spectral characteristic curves obtained by radiometer. The experimental results show that the spectral curves obtained from the recovered spectral images are basically the same as the spectral characteristics curves extracted by radiometer. Two groups of spectral recovery experimental results verify the effectiveness of the proposed identification method for spectral recovery matrix.