Method and apparatus for estimating and compensating for jitter in digital video
First Claim
1. A method of estimating jitter between two video frames in a digital video sequence, comprising:
- comparing a pixel subset of one video frame to candidate pixel subsets within a search area in the other video frame to determine a preliminary matching pixel subset from the candidate pixel subsets;
determining an actual matching pixel subset from the other video frame based on the location of the preliminary matching pixel subset relative to said search area; and
calculating a global jitter vector based on the pixel subset and the actual matching pixel subset thereby to estimate the jitter;
checking the reliability of the actual matching pixel subset; and
only calculating the global jitter vector if the actual matching pixel subset is deemed to be reliable;
wherein reliability of the actual matching pixel subset is based on at least one of frame contrast measure and steepness measure; and
wherein said determining comprises;
determining if the preliminary matching pixel subset is adjacent a border of the search area;
if not, designating the preliminary matching pixel subset as the actual matching pixel subset;
otherwise, altering the search area; and
comparing the pixel subset to candidate pixel subsets within the altered search area to determine the actual matching pixel subset;
wherein said altering comprises;
shifting the search area in the direction of the preliminary matching pixel subset.
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Accused Products
Abstract
A method of estimating and compensating for jitter between two video frames in a digital video sequence comprises comparing a pixel subset in one video frame to candidate matching pixel subsets within a search area in the other video frame to obtain a preliminary matching pixel subset. Based on the location of the preliminary matching pixel subset, an adapted search area is formed and the comparing is continued within the adapted search area to obtain a final matching pixel subset. Motion is calculated between the video frames based on the final match thereby to estimate the jitter. The video frames are then transformed based on the estimated jitter.
30 Citations
26 Claims
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1. A method of estimating jitter between two video frames in a digital video sequence, comprising:
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comparing a pixel subset of one video frame to candidate pixel subsets within a search area in the other video frame to determine a preliminary matching pixel subset from the candidate pixel subsets; determining an actual matching pixel subset from the other video frame based on the location of the preliminary matching pixel subset relative to said search area; and calculating a global jitter vector based on the pixel subset and the actual matching pixel subset thereby to estimate the jitter; checking the reliability of the actual matching pixel subset; and only calculating the global jitter vector if the actual matching pixel subset is deemed to be reliable; wherein reliability of the actual matching pixel subset is based on at least one of frame contrast measure and steepness measure; and wherein said determining comprises; determining if the preliminary matching pixel subset is adjacent a border of the search area; if not, designating the preliminary matching pixel subset as the actual matching pixel subset; otherwise, altering the search area; and comparing the pixel subset to candidate pixel subsets within the altered search area to determine the actual matching pixel subset; wherein said altering comprises; shifting the search area in the direction of the preliminary matching pixel subset. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. An apparatus for estimating jitter between two video frames in a digital video sequence, comprising:
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a frame comparator comparing a pixel subset of one video frame to candidate pixel subsets within a search area in the other video frame to determine a preliminary matching pixel subset from the candidate pixel subsets; a match position estimator determining the location of the preliminary matching pixel subset relative to said search area; the frame comparator determining an actual matching pixel subset from the other video frame based on the location determined by the match position estimator; and a jitter estimator calculating a global jitter vector based on the pixel subset and the actual matching pixel subset thereby to estimate the jitter; wherein said jitter estimator; checks the reliability of the actual matching pixel subset; and only calculates the global jitter vector if the actual matching pixel subset is deemed to be reliable; wherein reliability of the actual matching pixel subset is based on at least one of frame contrast measure and steepness measure; and wherein said frame comparator; determines if the preliminary matching pixel subset is adjacent a border of the search area; if not, designates the preliminary matching pixel subset as the actual matching pixel subset; otherwise, alters the search area; and compares the pixel subset to candidate pixel subsets within the altered search area to determine the actual matching pixel subset; wherein said altering comprises; shifting the search area in the direction of the preliminary matching pixel subset. - View Dependent Claims (23, 24)
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25. A non-transitory computer readable medium embodying a computer program for estimating jitter between two video frames in a digital video sequence, the computer program, when executed, performs a method comprising:
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comparing a pixel subset of one video frame to candidate pixel subsets within a search area in the other video frame to determine a preliminary matching pixel subset from the candidate pixel subsets; determining an actual matching pixel subset from the other video frame based on the location of the preliminary matching pixel subset relative to said search area; and calculating a global jitter vector based on the pixel subset and the actual matching pixel subset thereby to estimate the jitter; checking the reliability of the actual matching pixel subset; and only calculating the global jitter vector if the actual matching pixel subset is deemed to be reliable; wherein reliability of the actual matching pixel subset is based on at least one of frame contrast measure and steepness measure; and wherein said determining comprises; determining if the preliminary matching pixel subset is adjacent a border of the search area; if not, designating the preliminary matching pixel subset as the actual matching pixel subset; otherwise, altering the search area; and comparing the pixel subset to candidate pixel subsets within the altered search area to determine the actual matching pixel subset; wherein said altering comprises; shifting the search area in the direction of the preliminary matching pixel subset. - View Dependent Claims (26)
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Specification