论CCD相机标定的内、外因素：畸变模型与信噪比

决定ＣＣＤ相机定标的精度不仅取决于成像系统中已存在的各种畸变（模型），同时取决于这些畸变在数据噪声中所占的比例－信噪比，前者称为决定相机标定精度的内在因素，后者称为决定相机标定精度的外在因素。本文提出了利用统计显著性检验、相关系数检验来选择畸变模型。各种不同的模拟数据及实际数据试验表明：（１）不同的成像系统中畸变模型是不一致的，必须用显著性检验方法来检验畸变模型是否显著，删除非显著性畸变；（２）在选择多个畸变参数作为畸变模型时，畸变参数之间、畸变参数与标定参数之间有时存在强相关，必须用相关性检验这些参数，删除强相关畸变参数。本文还提出了用畸变在数据噪声中所占有的比例－信噪比作为衡量以多高的精度去量测影像坐标才能补偿畸变的标准，模拟试验数据表明：信噪比越大，畸变越能补偿；反之补偿就小．而且定标精度与信噪比是指数函数关系。

The Intrinsic and extrinsic Factor of CCD Calibration:Distortion Model and Signal to Noise Ratio

The precision of CCD calibration depends on both distortion models in imagery process and signal-noise-ratio.The former is called intrinsic factor,and the latter is called extrinsic factor.The paper presents to select distortion model using statistic notable check and correlation coefficient check,and use signal-noise-ratio,which is a proportion of distortions in data noise,as criterion.A large number of simulative and realistic experiments show(1) Various distortion models exist in various imagery system;(2)There is high correlation among distortion parameters or between distortion parameters and camera parameters;In addition,(3) The larger the signal-tonoise ratio is,the larger the compensation capability to distortion is,on the contrary,the smaller the ratio of signal-to-noise is,the smaller the compensation capability is;(4)The relation of precision improving with signal-to-noise ratio is exponential function.