空间矩和Zernike矩亚像素边缘算子分析

讨论了空间矩、Zernike矩两个亚像素边缘算子的运行时间和定位精度。分析结果表明,Zernike具有更快的运行速度,当计算3个用于边缘定位的参数时,其运行时间较空间矩算子节约了50%。理论分析了空间矩和Zernike矩算子的关系,并推导出了两个算子边缘距离为l的差值公式。测试结果表明,当两个算子的l都限制在中心像素内时,空间矩算子的边缘厚度多达3个像素,而Zernike矩算子的边缘厚度小于1个像素,可见Zernike矩算子的定位精度为真正的亚像素级。经比较,Zernike矩算子的运行时间和定位精度均好于空间矩算子。

Analysis on spatial moments and Zernike moments subpixel edge operators

Running time and location accuracy of spatial moments and Zernike moments subpixel edge operator are discussed. Analysis result shows that masks of Zernike moments operator is only half of spatial moments operator, therefore, 50% running time can be saved for Zernike moments operator when necessary three edge parameters are calculated. The relationship of whole edge parameters between spatial moments and Zernike moments operator is analyzed, and D-value formula of location position l is given. While l is limited into central pixel of a sampled window, testing result shows that edge thickness is basically less than one pixel for Zernike moments operator, but it is more than three pixel for spatial moments operator, it demonstrates Zernike moments operator can performed real subpixel-level edge detection. Therefore, both running time and location accuracy of Zernike moments operator are better than that of spatial moments operator.