EP0637894A2
Expired / Lapsed
EP
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Apparatus and method for detecting motion vectors to half-pixel accuracy
Assignee: WiniaDaewoo Co Ltd
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Filing: 1994-07-20
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Granted: —
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Expires: 2014-07-20
Abstract
Abstract Motion vectors between a current frame and its preceding frame of video signals are optimally determined to a half-pixel accuracy by finding a plurality of full-pixel resolution motion vectors corresponding to a plurality of best matching blocks in a search region; and, thereafter, deriving a half-pixel resolution motion vector by selecting an half-pixel resolution block which yields the minimum error function out of all possible half-pixel resolution candidate blocks included in half-pixel resolution search regions, each of which corresponding to one of the full-pixel motion vectors.
Inventors
- 👤 Sang-Ho Kim
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 23:41
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/50; H04N19/503; H04N19/51; H04N19/523; H04N19/53
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
128 words
A method for determining motion vectors between a current frame and its preceding frame of video signals to a half-pixel accuracy, wherein the current frame is divided into a multiplicity of search blocks of an identical size and the preceding frame is made to include a corresponding number of search regions, each search region having a plurality of candidate blocks of said identical size, which comprises the steps of: (a) determining a predetermined number of full-pixel resolution motion vectors for each of the search blocks in the current frame, wherein said predetermined number is greater than one but smaller than the number of candidate blocks in a search region; and (b) determining a half-pixel resolution motion vector based on the full-pixel resolution motion vectors determined in step (a).
Claim 2
Dependent Claim
81 words
The method in accordance with claim 1, wherein said step (a) includes the steps of: (a1) calculating error functions, each of said error functions representing the difference between a search block in the current frame and each of full-pixel resolution candidate blocks, having an integer valued displacement, included in the corresponding search region of the previous frame; and (a2) selecting the predetermined number of full-pixel resolution motion vectors for the search block which yield smallest error functions in the predetermined number.
Claim 3
Dependent Claim
132 words
The method in accordance with claim 1, wherein said step (b) includes the steps of: (b1) obtaining half-pixel resolution candidate blocks in the half -pixel resolution search region corresponding to one of said full-pixel resolution motion vectors; (b2) calculating and comparing error functions, each of said error functions representing the difference between the search block in the current frame and each of the half-pixel resolution candidate blocks, thereby selecting a half-pixel resolution block which yields a minimum error function; and (b3) repeating steps (b1) and (b2) for a next full-pixel resolution motion vector until all of the half-pixel resolution candidate blocks in the last half-pixel resolution search region corresponding to the last full-pixel resolution motion vector of the block are processed, to thereby determine the half-pixel resolution motion vector of the block.
Claim 4
Dependent Claim
189 words
The method in accordance with claim 2, wherein said step (a2) further includes the steps of: (a21) initializing a first group of variables, SE i 's, which stores the predetermined number of error functions, wherein i is a positive integer ranging from 1 to the predetermined number; (a22) reading an error function E and a displacement D corresponding to a candidate block in a search region of the previous frame; (a23) comparing said E with the values stored in said SE i 's; (a24) rearranging the values stored in said SE i 's and E in an ascending order and discarding a largest one; (a25) storing the remaining values stored in said SE i 's and E in said SE i 's for the processing of a next candidate block; (a26) storing displacements, each of said displacements corresponding to one of the values stored in SE i 's in a second group of variables, SD i 's, wherein i is the positive integer ranging from 1 to the predetermined value; and (a27) repeating steps (a22) through (a26) until all of the candidate blocks in the search region are processed.
Claim 5
Independent Claim
140 words
An apparatus for determining motion vectors between a current frame and its preceding frame of video signals to a half-pixel accuracy, wherein the current frame is divided into a multiplicity of search blocks of an identical size and the preceding frame is made to include a corresponding number of search regions, each search region having a plurality of candidate blocks of said identical size, comprising: a full-pixel resolution motion vector detector for determining a predetermined number of full-pixel resolution motion vectors for each of the search blocks in the current frame, wherein said predetermined number is greater than one but smaller than the number of candidate blocks in a search region; and a half-pixel resolution motion vector detector for determining a half-pixel resolution motion vector based on the full-pixel resolution motion vectors determined at the full-pixel resolution motion vector detector.
Claim 6
Dependent Claim
81 words
The apparatus of claim 5, wherein the full-pixel resolution motion vector detector includes: means for calculating error functions, each of said error functions representing the difference between a search block in the current frame and each of full-pixel resolution candidate blocks, having an integer valued displacement, included in the corresponding search region of the previous frame; and means for selecting the predetermined number of full-pixel resolution motion vectors for the search block which yield smallest error functions in the predetermined number.
Claim 7
Dependent Claim
56 words
The apparatus of claim 5, wherein the half-pixel resolution motion vector detector includes: means for obtaining half-pixel resolution candidate blocks in the half-pixel resolution search region corresponding to one of said full-pixel resolution motion vectors; and means for calculating and comparing said error functions, thereby selecting a half-pixel resolution block which yields a minimum error function.
References Cited (Backward Citations)
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