编码孔径成像光谱仪中编码元形变的分析校正

Analysis and Correction of Coded Pixel Distortion in Coded Aperture Imaging Spectrometer

在编码孔径成像光谱仪中,由于数字微镜器件(DMD)工作在倾斜光路中,导致编码元在探测器上产生非对称形变,解码时无法确定所获编码图像各像素对应的编码方式。为解决这一问题,提出"非对称形变的规则条纹校正"方法,通过规则条纹在探测器上产生变化,直观地观察编码元形变,根据已知条纹规则,即可定量分析图像的形变量并进行校正。该方法可以保证在系统全视场清晰成像的前提下实现对编码图像的校正。首先介绍了所设计光谱仪的成像原理以及编码元的形变原因,其次在实验过程中调节探测器以获得全清晰视场,最后利用提出的方法对编码图像进行处理。实验表明,处理后图像与理论值的相似度比未处理时高37.87%,图像恢复DMD加载的图样形状,为后续的解码运算奠定了基础。

Since the digital mircomirror device （DMD） is working in slant optical path in the coded aperture imaging spectrometer, the coded pixel will generate unsymmetrical distortion on detector, which will make it unable to determine the coded method corresponding to each pixel of obtained coded image when decoding. In order to solve this problem, this paper proposes a method of ＂unsymmetrical deformation regular stripe calibration＂. Through the changes that the regular stripe produces on the detector, the deformation of the coded pixel is visually observed. According to the known stripe rule, the deformation of the image can be quantitatively analyzed and corrected. This method can ensure the correction of the coded image under the premise of clear imaging of the entire field of view of the system. Firstly, the imaging principle of the designed spectrometer and the deformation reason of the coded pixel are introduced. Secondly, the detector is adjusted during the experiment to obtain a full-clear field of view. Finally, the proposed method is used to process the coded image. Experiments show that the similarity between the processed image and the theoretical value is 37.87% higher than that of the unprocessed image. The image restores the pattern shape loaded by the DMD, which lays the foundation for the next decoded operation.