Design Of Integrated Polarization Sensor And Research On Its Calibration Agorithm

Bionic polarization navigation is a kind of autonomous navigation method which relies on the stable sky polarization distribution pattern in nature.It has the advantages of strong anti-interference ability,complete autonomy and no error accumulation over time.Existing bionic polarization navigation sensors can be divided into photodiode type and CMOS image sensor(CIS)type according to their different photosensitive components.The CIS polarization sensor is composed of an image sensor,a multi-channel polarizer and an optical lens.Because its instantaneous field of view error is small and more polarization information can be obtained each time,its robustness and adaptability have a larger space for development.However,most of the existing CIS polarization sensors are built by image sensor modules and development boards,which have the problem of redundant components with large volume.In addition,due to the limitation of manufacturing process,the photoelectric conversion deviation of CIS and the transmission deviation of metal nanometer grating are the main factors affecting the angular measurement accuracy of the sensor.However,the calibration parameters of the existing calibration methods are not specific enough,and the robustness and adaptability need to be improved.In order to solve the above problems,this paper first introduces an integrated CIS polarization navigation sensor,which is mainly composed of optical lens,four-directional metal nanometer grating,CIS and micro-control unit(MCU).The sensor features high integration of components,small size and no redundancy of components.Then,according to the performance model of each component of the polarization sensor,a new full parameter calibration method is proposed,which can accurately solve the performance parameters of the Mueller matrix and the gain and dark current of CIS at all pixel positions,so as to achieve the calibration purpose.On this basis,a mode-based region extraction algorithm is proposed,which makes full use of the statistical law of the original light intensity and extinction ratio of all prime regions to extract the effective region of the sensor,so as to eliminate the defective region and uneven region of the sensor's photosensor surface,and reduce the error of the polarization angle calculation of the sensor.Finally,indoor and outdoor experimental platforms are built respectively,and indoor and outdoor sensor verification experiments are carried out to prove the performance of the sensor and the effectiveness of the above calibration and region extraction algorithm.The indoor and outdoor experiment results show that the full parameter calibration algorithm can accurately solve the performance parameters of the sensor,which can effectively improve the accuracy and robustness of the polarization angle solution of the sensor.And the extinction ratio image obtained in the calibration process can reflect the grating defects that the original light intensity image cannot show.Therefore,the effective region extraction algorithm based on the mode of extinction ratio image and original light intensity image can more accurately eliminate the defect area and the shaded area on the sensory surface of the sensor,and further improve the calculation accuracy of polarization angle.