Analysis And Experimental Research On Non-uniformity Of Non-scanning Ladad Baseed On APD Arrays

With the development of the society, the requirement of capture information isincreasing all the time. Photoelectric detector3D imaging laser radar technologywhich based on APD array can detect the distance-angle-angle information of thetarget. It can describe the three-dimensional contour of the target so intuitively thatget information more quickly and make it more intuitive and accurate. Now it iswidely used in military reconnaissance guidance, medical imaging, urban planningand other fields. The imaging quality is determined by the performance parametersof the laser radar, and the uniformity of detection accuracy is the key to theperformance parameters of the laser array radar. The influence of the heterogeneityof APD array to the laser radar system performance is discussed in the paper andcorrection scheme is proposed to improve the quality of imaging.APD array without scanning laser radar system is designed from the principleof APD array, the system structure and working principles are introduced in details,the characteristics of the noise of APD detector array is analyzed. The principle ofdammann grating of spectral emission system is expounded, the transmissionproperties of the lattice beam is studied, the conclusion is discovered that blind areaexist in the diffraction grating lattice from the generalized Huygens-Fresneldiffraction theory.The uniformity of the APD array laser radar is analyzed starting from theresponse of the APD detector array. The heterogeneity of the APD array laser radaris mainly caused by optical system and array detectors. The light is uniformdistribution which the APD array detector received because of the optical system; itdirectly leads to the uneven of the detector response to echo signal that the APDarray detector gain non-uniformity. APD array laser radar resulted in non-uniformityin time response, because of the difference between echo signals in different timeand different pixel detector. It is developed that non-uniformity can cause thedistortion of the grey-scale imaging, by combining the equation of the APD laserradar with the optical response characteristics of the photoelectric detector. It isfound that the distance of the array laser radar is also influenced by non-uniformity,by the study of the timing accuracy and the influence to the ranging accuracy of theradar system caused by SNR.Based on the above research, it is proposed that correct the non-uniformity ofthe intensity image by the use of variable gain method and image filtering method.Simulation results show that the system obtained after correction signal strength value and the uniformity of the distance detection accuracy has been greatlyimproved.Finally, based on existing resource, we performed an experiment to study APDarray ladar ranging, experimental results verified the existence of array ladar systemgain non-uniformity, while proved ranging accuracy uniformity is influenced bygain. Provided experimental evidence to research non-uniformity of APD arraynon-scanning ladar system.