Research On Optimizing Contrast Of Imaging Based On Polarimetric In Complex Imaging Environment

Polarimetric imaging systems can obtain the information that is not visible on intensity images.Therefore,it is applied in many fields such as target detection and image quality enhancement.Based on polarimetric imaging,we investigate the algorithm of contrast optimization under uneven illumination and the underwater image recovery algorithm.The uneven illumination could hamper the target detection.We propose a method of illumination compensation and contrast optimization for Stokes polarimetric imaging.In addition,based on the model of underwater image formation,we consider the polarization effect of the object,and propose a method of underwater image recovery based on the correction of transmittance map.The major works of the thesis as follows:1)Investigating the method of measuring the polarization parameters and polarimetric imaging systems.Based on the conditions of the laboratory,we set up the imaging optics system with polarization state analyzer(PSA)consists of a rotating quarter wave plate and a rotating linear polarizer.We control the CCD as well as acquire and display the image by writing a LabView program,and thus complete the general design of a passive polarimetric imaging system.The light source is a He-Ne laser with the wavelength of 632.8 nm which applies to Stokes vector measurement of monochromatic light.2)Investigating the method which could increase the performance of target detection.We proposed the method of using degree of polarization(DOP)image to obtain the information that is not visible on intensity images.We have proposed a method with taking into account the statistics of spatial fluctuations by adjusting the state of PSA.Moreover,the uneven illumination could cause the significant spatial intensity fluctuations in the scene.We propose a method of illumination compensation and contrast optimization for Stokes polarimetric imaging,which allows significantly increasing the performance of target detection under uneven illumination.3)Research on the physical model of underwater image formation of active polarized illumination and the behavior of the polarized light in turbid water.Based on the polarimetric imaging system,expounding the method of underwater image recovery.We consider the polarization effect of the object,and propose a method of retrieving the objects radiance based on estimating the polarized-difference image of the target signal by a curve fitting method.The method could overcome difficulty that the previous methods could fail when the depolarization effect of the object is low and the quality of the underwater image can be effectively enhanced.