利用CRLB的数字摄影测量人工标志定位不确定性评估

考虑影像形成的物理过程,针对叠加零均值高斯白噪声的标志定位模型,利用最大似然估计理论,推导出了基于标志定位不确定性理论的误差性能克拉美-罗下限(Cramér-Rao lower bound,CRLB),同时确定了CRLB在一定置信水平下的置信区间。以圆形标志实验为例,分析了噪声水平和标志大小两个因素对CRLB的影响。

Estimation of Artificial Mark Location Uncertainty with CRLB in Digital Photogrammetry

The uncertainly of artificial mark locations in digital photogrammetry is badly affected by imaging system.Aiming at mark location models with overlapped zero-mean Gaussian white noise and considering the physical process of imaging,a theoretical error performance Cramér-Rao lower bound based on the uncertainty theory of mark location was derived through the theory of maximum likelihood estimation.And its corresponding confidence interval was also determined on a certain confidence level.With the same confidence level,the uncertainty of any practical locations operator can be estimated with the degree of closeness between its own confidence interval and theoretical confidence interval of CRLB.To assess the uncertainty of practical locations operator and design a new more precise mark locations operator,circular mark is taken as an example to illustrate the effects of noise level and mark size on CRLB.The results show that the precision based on CRLB can be achieved 0.015 pixel by choosing suitable mark radius and small noise standard deviation.