Study On Stray Light Characteristic Analysis And Correction Method Of Watercolor Image Spectrometer

Ocean color remote sensing refers to the use of airborne or space borne remote sensors to detect ocean color features. In essence, the detection of dim color target is the extraction of weak signal in strong background noise, which proposes high sensitivity requirement on the ocean color remote sensing instruments. In addition, high spectral resolution is necessary for the remote sensors on color feature extraction. The imaging spectrum technology can obtain a high spectral resolution and realize the continuous spectrum of the spectrum. At the same time, push broom imaging method can achieve a high sensitivity. Therefore the push broom imaging spectrometer is very consistent with the requirements of remote sensing.In this paper, a principle prototype of the push broom imaging spectrometer used in the ocean color remote sensing is studied. Generally speaking, stray light of cross track in this type of instrument affects the imaging quality and the quantitative use of the instrument. This paper focuses on the analysis of the performance of stray light of the instrument, and investigates the components which may produce stray light. And then study the stray light distribution of the instrument, establish its distribution model, and correct the stray light by it. Finally, the method of recovering the saturation data is proposed to deal with the saturation problem of the saturation white clouds.The main contents of this paper include:1. Analysis the characteristics of the imaging experiment outside the laboratory in presence of stray light phenomenon, and design the experiments to investigate the defective components for the lens, light splitting component, filter of second order spectra, detector and circuit in the system, respectively. And then locate the straying light components.2. The experiments of the measurement of spatial distribution of stray light in the instrument with different field of view are designed and the distribution characteristics are analyzed in detail. According to its distribution, the stray light is decomposed into the linear shift component and the linear shift-invariant component. Based on this, the distribution model of the stray light is established and the matrix method is designed to correct the stray light of the instrument. In addition, the field of image restoration is used to correct the stray light of the instrument;3. In order to achieve the elimination of the interference of the stray light interference from clouds to signal of ocean color, recovering the saturation signal of the high brightness clouds is required. By studying the correction channel of smear of the instrument, determine the linear relationship between it and the other working channels data, theoretically. The linear relationship is confirmed by integrating sphere and sunlight. Based on this, cloud target saturation recovery method is proposed, namely to recover the saturated work channels data in a certain extent by unsaturated data of smear channel and the linear relationship between unsaturated data of smear correction channel and other working channels.