Multiplicative Noise Analysis And Processing Methed In Distance Image Of Imaging Lidar

Laser radar detection technology is the hot area of research at home and abroad，itis widely used in many aspects, such as spaceflight, meteorology, medical, industrial,early warning, missile guidance and civilian detection. The imaging laser radar can gainnot only the strength of the detect target but also the distance of the detect target. Butthe image is often accompanied by noise, especially the multiplicative noise, what isrelated to the original signal and hard to be removed. It affects image quality andranging accuracy seriously. The research of laser radar in China started relatively later.At present according to the analysis of the imaging laser radar multiplicative noise andprocessing method is not of the system. In this paper, analyze the multiplicative noise inimaging laser radar based on ICCD gain modulation. Showing the noise processingmethod respectively from the airspace domain and frequency domain in the system.Radar image processing results of each method are compared and analyzed theadvantages and disadvantages.The multiplicative noise in ICCD gain modulation imaging laser radar from thenoise of imaging device, what is associated with the image signal in the form ofadditional gain. And noise from the imaging device after micro channel plate into amultiplicative noise. In the spatial domain, using median filter, median filter andhomomorphic filtering method processing to laser radar image. Homomorphic filteringis the method just for multiplicative noise and the best treatment effect of themultiplicative noise. But this method could be interferenced if there is additive noise.So in combination with a variety of filtering methods can get a better effect ofmultiplicative noise cancellation. In the frequency domain, using low-pass, band-passand multi-scale wavelet transform filtering method of radar image processing based onthe image spectrum diagram. One of them, the multi-scale wavelet transform filteringcan effectively filter out the multiplicative noise at the same time keeping the targetedge. When the radar image contains multiplicative and additive noise at the same time,a parallel processing of two kinds of noise is needed. Use separate target imagesegmentation will be detected, for the target the homomorphic filtering method isadopted to remove multiplicative noise and for background median filtering method isadopted to remove the additive noise. That can prevent the two kinds of noiseinterference with each other. Using of neighborhood pixel gray value fluctuation tojudge the multiplicative noise. According to the center of pixels and the pixels aroundfour field gradient changes to a distinction between additive and multiplicative noise,use different methods to filter in different settings. Based on this, advances a kind of advanced six neighborhood structure and processing method of the image. This methedcan make better using of neighborhood information for distinguishing noise type andget a better filtering effect.