Dept. of Eng., Cambridge Univ.
IEEE Trans Image Process. 1993;2(1):2-17. doi: 10.1109/83.210861.
A frequency-domain algorithm for motion estimation based on overlapped transforms of the image data is developed as an alternative to block matching methods. The complex lapped transform (CLT) is first defined by extending the lapped orthogonal transform (LOT) to have complex basis functions. The CLT basis functions decay smoothly to zero at their end points, and overlap by 2:1 when a data sequence is transformed. A method for estimating cross-correlation functions in the CLT domain is developed. This forms the basis of a motion estimation algorithm that calculates vectors for overlapping, windowed regions of data. The overlapping data window used has no block edge discontinuities and results in smoother motion fields. Furthermore, when motion compensation is performed using similar overlapping regions, the algorithm gives comparable or smaller prediction errors than standard models using exhaustive search block matching, and computational load is lower for larger displacement ranges and block sizes.
提出了一种基于图像数据重叠变换的频域运动估计算法，作为块匹配方法的替代方法。通过将重叠正交变换（LOT）扩展到具有复数基函数，首先定义复数重叠变换（CLT）。CLT 基函数在其端点处平滑地衰减为零，并且当数据序列被变换时以 2:1 的方式重叠。开发了一种在 CLT 域中估计互相关函数的方法。这构成了运动估计算法的基础，该算法计算用于重叠、窗口化数据区域的向量。使用的重叠数据窗口没有块边缘不连续性，并且导致更平滑的运动场。此外，当使用类似的重叠区域进行运动补偿时，该算法给出的预测误差与使用穷举搜索块匹配的标准模型相当或更小，并且对于更大的位移范围和块大小，计算负载更低。
