彩色图像的单应矩阵估计算法

An algorithm for estimating the homography of color images

图像间单应矩阵估计是图像配准与图像拼接中的核心问题,传统的估计方法是针对灰度图像的算法。本文以分层运动估计为基础提出了彩色图像的平面单应矩阵的估计算法。此算法采用色度与饱和度不变为约束条件得到彩色图像的光流方程,显著改善了亮度不变约束的不足之处;采用最优导数计算滤波器计算图像导数,提高了算法的精度与稳健性;采用尺度总体最小二乘方法代替最小二乘或总体最小二乘方法来估计模型参数,提高了算法对于图像噪声的适应性。实验结果表明,该算法稳健性好、精度高,而且可以得到稠密的匹配点。

The estimation of intra-frames homography is a key issue to image registration and mosaicing, and the conventional estimation methods are only feasible for the gray images. In this paper, the homographic matrix of two colored consecutive frames is proposed based on a hierarchical motion estimation approach. In our algorithm, the new constraints, viz. , the conservation of hue and saturation, are adopted to obtain optical flow equations and the defects of the lightness conservation are remarkably decreased. Meanwhile, the numerical derivatives of the images are obtained by using the optimal muhi-dimensional derivative filters which enhance the robustness and accuracy of the algorithm. Furthermore, the scaled total least squares （STLS） approach instead of the least squares （LS） or total least squares （TLS） method is used to estimate the parameters of the homography and the adaptability for the image noise are enlarged greatly. The experiment results with synthetical and real images show that the algorithm is of high robustness and accuracy and the dense image corresponding points can be obtained as byproducts.