激光散斑引起的象强度中心漂移的理论计算

Theoretical Calculation for Centroid Shift of Image Due to Laser Speckle

在传感技术的许多应用中，经常需要用探测器在象面上接收一个成象斑点，以便从中提取空间深度和位置信息。由于激光的高亮度和极好的方向性，使之成为非常理想的投影光源。但是由于激光散斑噪声的存在，使得象斑强度中心与象斑几何中心不再重合，导致对物体空间深度和位置的估计错误。本文从散斑统计光学理论出发，针对四种不同的光瞳函数，提出在相干照明条件下象斑强度中心计算方法。

In many sensing applications,an imaging spot must be received in the image plane with detector to extract the data of spatial depth and lateral position of the object.Because of brightness and directionality,laser has become into an excellent projection light source.With the influence of laser speckle noise,the image spot intensity center cannot overlap with image spot geometric center.This leads to a false estimation of the spatial depth and position of object.Based on the speckle statistic optics theory,a calculation method for image spot center intensity for the four different pupil functions under the coherent lighting condition has be proposed.The analytic expression for the basic uncertainty in position measurement has been derived in the paper.