Source: http://www.google.com/patents/US7852939?dq=5,381,459
Timestamp: 2016-09-28 09:28:06
Document Index: 96357367

Matched Legal Cases: ['Application No. 2004', 'art 201', 'art 202', 'art 202', 'art 202', 'art 203']

Patent US7852939 - Motion vector detection method and device of the same - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsWhen a search is made for a motion vector of a moving image, a motion vector search desirable against a hard movement is devised to be made with a small processing amount, and a motion vector detection device includes a wide range motion vector search part, a narrow range motion vector search part, a...http://www.google.com/patents/US7852939?utm_source=gb-gplus-sharePatent US7852939 - Motion vector detection method and device of the sameAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS7852939 B2Publication typeGrantApplication numberUS 11/252,244Publication dateDec 14, 2010Filing dateOct 18, 2005Priority dateOct 18, 2004Fee statusPaidAlso published asUS20070086525Publication number11252244, 252244, US 7852939 B2, US 7852939B2, US-B2-7852939, US7852939 B2, US7852939B2InventorsWataru AsanoOriginal AssigneeKabushiki Kaisha ToshibaExport CitationBiBTeX, EndNote, RefManPatent Citations (9), Non-Patent Citations (1), Referenced by (2), Classifications (19), Legal Events (2) External Links: USPTO, USPTO Assignment, EspacenetMotion vector detection method and device of the same
US 7852939 B2Abstract
When a search is made for a motion vector of a moving image, a motion vector search desirable against a hard movement is devised to be made with a small processing amount, and a motion vector detection device includes a wide range motion vector search part, a narrow range motion vector search part, a motion vector prediction part, and a motion vector re-search part. A rough search is made at equal intervals on an inputted image while a corresponding position in the reference image is made the center; a fine search is made in the vicinity of a predicted value of the motion vector only at one stage in accordance with a search format of a gradient method; and from a result of both, motion vector detection is performed as a motion vector search start point by the gradient method.
obtaining a wide range search evaluation value by searching for a motion vector for the currently processed block at intervals of “n” pixels in a wide search range having “a” pixels and having a wide range search center point which is at a position in the reference image corresponding to a position of the currently processed block in the detection object image;
predicting a predicted motion vector for the currently processed block from past motion vectors for peripheral blocks of the currently processed block, and obtaining a narrow range search evaluation value by searching for the motion vector for the currently processed block at intervals of “m” pixels (n>m>=1) in a narrow search range having “b” pixels (a>b>1) and having a narrow range search center point which is at a position of the predicted motion vector;
detecting the motion vector for the currently processed block by re-searching in a re-search range having “c” pixels (a>c>=b) and a center at the re-search center point,
wherein “n”, “a”, “m”, “b” and “c” are positive integers.
4. The motion vector detection method according to claim 1, wherein, when the wide range search evaluation value is obtained, the wide search range is a range of at least 20 pixels from the wide range search center point, and the “n” pixels are 16 pixels.
5. The motion vector detection method according to claim 1, wherein when the narrow range search evaluation value is obtained, the narrow search range is a range of 2 pixels from the narrow range search center point, and the “m” pixels are two pixels.
obtaining a wide range search evaluation value by searching for a motion vector for a currently processed block at intervals of “n” pixels in a wide search range having “a” pixels and having a wide range search center point which is at a position in the reference image corresponding to a position of the currently processed block in the detection object image;
obtaining a wide range search evaluation value by searching for the motion vector for the currently processed block at intervals of “n” pixels in a wide search range having “a” pixels and having a wide range search center point which is at a position in the reference image corresponding to a position of the currently processed block in the detection object image;
wherein “n”, “a”, “m”, “b” and “c” are positive integers. Description
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2004-303405, filed on Oct. 18, 2004; the entire contents of which are incorporated herein by reference.
The present invention relates to a motion vector detection method associated with moving image coding and a device of the same.
In an international standard of a moving image coding system such as MPEG-2, MPEG-4 or H.264, a motion vector indicating that a block to be coded resembles which position of a reference image is used. When the motion vector is proper, an error between the block and the reference image becomes small, and efficient coding becomes possible. On the other hand, when the motion vector is improper, an error becomes large, and coding efficiency is lowered. As stated above, the accuracy of the motion vector has a large influence on the coding efficiency.
Since motion vector search generally requires a large amount of operation, efficient motion vector search methods have been proposed. As examples of the high speed movement search methods, a hierarchical search method (see, for example, JP-A-2004-129099) and a search by a gradient method (see, for example, Shan Zhu and Kai-Kuang Ma, “A New Diamond Search Algorithm for Fast Block-Matching Motion Estimation”, IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 9, NO. 2, FEBRUARY 2000) are named.
According to embodiments of the present invention, a motion vector detection method for detecting a motion vector by comparing a detection object image, which is one image in a moving picture and is subjected to the detecting of the motion vector, with a reference image that is another image in the moving picture at a time different from the detection object image, includes:
(1) searching for the motion vector at intervals of “n” pixels in a wide search range that has “a” pixels, or pixels as many as “a”, and is centered at a wide range search center point, which point is in the reference image at a position matching one block in the detection object image, so as to obtain a wide range search evaluation value;
(2) predicting a predicted motion vector from a past motion vector and searching for the motion vector at intervals of “m” pixels (n>m>=1) in a narrow search range having “b” pixels (a>b>1) that is centered at a narrow range search center point, which point means a position of the predicted motion vector in the reference image, as to obtain a narrow range search evaluation value;
(4) detecting the motion vector by re-searching for the motion vector in a re-search range having “c” pixels (a>c>=b) that is centered at the re-search center point.
FIG. 1 is a block diagram showing a structure of a moving image coding device including a motion vector detection device according to an embodiment of the invention.
Hereinafter, an embodiment of a motion vector detection device of the present invention will be described in detail with reference to the drawings.
Next, the wide range motion vector search part 201 roughly searches for a motion vector (step 103). Specifically, when a motion vector search range in the horizontal direction is �x pixels, and a search range in the vertical direction is �y pixels, a search is made every “n” pixels while (0, 0) is made the center. That is, a search of points of (i*n, j*n) is made. Here, i and j denote integers, and satisfy a relation of −x≦i*n≦x and −y≦j*n≦y.
For example, in the case where the horizontal direction search range is �20, the vertical direction search range is �10, and the search interval is n=8, a search of in total 15 points of (0, �8), (�8, �8), (�16, �8), (0, 0), (�8, 0) and (�16, 0) is made (see FIG. 4). Here, “1” in FIG. 4 denotes a search point, and a solid line denotes a detected motion vector. When the search range x and y is widened, the number of search points is generally increased, however, when n is set to be large, even if the search range is widened, an increase of the number of search points can be prevented. Although this wide range search is excellent in that a large movement is easy to pursue, it has trouble in accurately pursuing a small movement.
The narrow range motion vector search part 202 searches positions of �“m” pixels, while the predicted motion vector (Px, Py) obtained in this way is made the center. Here, m denotes an integer smaller than n. That is, a search of in total 9 points of (Px, Py), (Px�m, Py), (Px, Py�m), (Px�m, Py�m) is made (see FIG. 6). Here, a dotted line of FIG. 6 denotes a predicted motion vector, “1” denotes a search point, and a solid line denotes a detected motion vector. The narrow range search is very excellent in the case where a movement is small and prediction easily comes true, however, in the case where the movement is large and random, there is a defect that a search of a place far removed from an actual movement is made.
Next, the narrow range motion vector search part 202 finely searches the vicinity of a predicted value of the motion vector (step S104). Specifically, the narrow range motion vector search part 202 makes a search on search points of a first step by a specified gradient method (for example, diamond search), while a motion vector (Px, Py) obtained by the motion vector prediction part 203 is made a start point (see FIG. 9). Here, a dotted line of FIG. 9 denotes a predicted motion vector, “1” denotes a search point, and a solid line denotes a detected motion vector.
The determined motion vector re-search start point is made a start point, and in accordance with the foregoing specified gradient method, a re-search is made for a motion vector (step S106, see FIG. 10). FIG. 10 shows a case where the evaluation value of the motion vector of the narrow range search is better than that of the motion vector of the wide range search, and the search is made in the order of “2”, “3” and “4”.
The invention is not limited to the embodiment, but may be variously modified within the scope of its gist.
As described above, embodiments consistent with the present invention are useful for a technique to compress a moving image and to perform transmission, recording and the like.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS6014181 *Oct 13, 1997Jan 11, 2000Sharp Laboratories Of America, Inc.Adaptive step-size motion estimation based on statistical sum of absolute differencesUS6195389 *Apr 16, 1998Feb 27, 2001Scientific-Atlanta, Inc.Motion estimation system and methodsUS6842483 *Sep 11, 2000Jan 11, 2005The Hong Kong University Of Science And TechnologyDevice, method and digital video encoder for block-matching motion estimationUS6876703 *Apr 27, 2001Apr 5, 2005Ub Video Inc.Method and apparatus for video codingUS6891891 *May 4, 2001May 10, 2005Stmicroelectronics S.R.L.Motion estimation process and systemUS7145950 *Jul 14, 2003Dec 5, 2006Primax Electronics Ltd.Method of motion vector determination in digital video compressionUS7236527 *May 8, 2003Jun 26, 2007Canon Kabushiki KaishaMotion vector search apparatus and methodUS20030161400 *Feb 27, 2002Aug 28, 2003Dinerstein Jonathan J.Method and system for improved diamond motion searchJP2004129099A Title not available* Cited by examinerNon-Patent CitationsReference1Zhu et al., "A new Diamond Search Algorithm for Fast Block-Matching Motion Estimation", IEEE Transactions on Image Processing, vol. 9, No. 2, Feb. 2000, pp. 287-290.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS8565312 *Apr 16, 2010Oct 22, 2013Sony CorporationImage processing method and image information coding apparatus using the sameUS20100272181 *Apr 16, 2010Oct 28, 2010Toshiharu TsuchiyaImage processing method and image information coding apparatus using the same* Cited by examinerClassifications U.S. Classification375/240.16International ClassificationH04N19/91, H04N19/533, G06T7/20, H04N19/60, H04N19/50, H04N19/51, H04N11/02, H04N7/12Cooperative ClassificationH04N19/52, H04N19/61, H04N19/56, H04N19/533, H04N19/57European ClassificationH04N7/26M4V, H04N7/50, H04N7/26M6E2, H04N7/26M2M, H04N7/26M4ILegal EventsDateCodeEventDescriptionDec 2, 2005ASAssignmentOwner name: KABUSHIKI KAISHA TOSHIBA, JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ASANO, WATARU;REEL/FRAME:017309/0736Effective date: 20051031May 14, 2014FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services