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The conventional diffractive optical imaging spectrometer uses the single-channel scheme, it is mainly aimed at simple targets, or gas targets with known spectral characteristics. The main disadvantage of conventional system is: if the target is a complex scene such as a natural scene, it's very difficult to demodulate spectral images accurately. Because, the focused and defocused spectral information are superimposed on each other. And, the real system has noise, manufacturing error, testing error and calibration error. So, it is difficult to correctly describe the dispersion parameters of the diffractive spectrometer, which will cause large errors of spectral demodulation accuracy. To solve this problem, an efficient system of diffractive spectral imaging is discussed, which includes a reference channel. Based on the conventional single-channel system, a grayscale camera or a color camera is added for imaging. It can provide a priori knowledge of complex scenes for the diffraction imaging channel. The data of the two channels are jointly processed to improve the final demodulation accuracy of the spectral data. The system composition and basic principles are introduced, the performance of the system is analyzed. The virtual simulation experiment of diffractive optic imaging is established. The simulation of diffractive imaging and spectral demodulation of complex scene have been finished. The demodulation output images are almost the same as the original input image. The experiment system of diffractive optic imaging in visible band is also established in the laboratory. Theoretical analysis, imaging simulation and imaging experiment have verified the validity and feasibility of the diffraction imaging system with reference channel. Compared with the single channel system, the spectral demodulation effect is obviously improved, which greatly improves the application potential and application value.
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