Method to improve accuracy and reliability of motion estimated with phase correlation

摘要

A method of improving accuracy and reliability of motion estimation is described herein. In one aspect, a 2D neighborhood of phase correlation peak is approximated with an outer-product of two 1D vectors to eliminate the sub-pixel error. In another aspect, estimation of reliability is improved. In yet another aspect, two-pass phase correlation is implemented to eliminate sub-pel motion bias.

主权项

1. A system for performing phase correlation to eliminate sub-pixel motion bias programmed in a memory in a device comprising:
a. a first pass module for performing a first pass of phase correlation; b. an offset module for offsetting a window in a reference picture using an offset according to motion determined in the first pass; c. a second pass module for performing a second pass of the phase correlation using an original current window and the offset reference window to generate a second phase correlation surface, wherein the second pass module further comprises:
i. an offset window function module for applying an offset window function to the window of a reference frame to obtain an offset frame result;ii. a third Fast Fourier Transform module for applying the Fast Fourier Transform to the offset frame result yielding a third set of complex values;iii. normalizing a product of the third set of complex values and a complex conjugate of a first set of complex values; andiv. a second inverse Fast Fourier Transform module for computing the inverse Fast Fourier Transform to yield a second phase correlation surface; d. a sub-pixel module for computing sub-pixel motion estimates based on the second phase correlation surface; and e. a final motion module for computing a final motion estimate by summing the offset and sub-pixel estimates.