Video coding system

• US 20030053545A1
• Filed: 10/08/2002
• Published: 03/20/2003
• Est. Priority Date: 09/20/1996
• Status: Abandoned Application

• Current Assignee: Sisvel International S.A. (Fineur International S.A.)
• Original Assignee: Sisvel International S.A. (Fineur International S.A.)
• Inventors: Karczewicz, Marta, Oktem, Levent, Lainema, Jani
• Application Number:
  US10/267,967
• Publication Number:
  US 20030053545A1
• Time in Patent Office: Days
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/53 Multi-resolution motion estimation; Hierarchical motion estimation
• CPC Class Codes: H04N 19/537 Motion estimation other than block-based
• CPC Class Codes: H04N 19/567 Motion estimation based on rate distortion criteria
• CPC Class Codes: H04N 19/80 Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation H04N19/635, H04N19/86 take precedence

Abstract

A motion estimation system for a video coder is disclosed. The system comprises an input for a video image (6) to be coded. It also comprises a series of motion estimators (2, 3) of varying complexity, for estimating a motion vector field between the received image (6) and a reference image (5). The subsequent motion estimator in the series is selected by a control means (4) if a prediction error associated with the motion vector field estimated by the currently selected motion estimator exceeds a predetermined threshold.

Claims

1. A motion estimation system for a video coder comprising:

means for receiving a video frame to be coded;

a series of motion estimators of varying complexity, for estimating a motion vector field between the said received frame and a reference frame; and

control means for selecting the subsequent motion estimator in the series only if a prediction error associated with the motion vector field estimated by the currently selected motion estimator exceeds a predetermined threshold.

2. A motion estimation system as claimed in claim 1, wherein the series of motion estimators comprises a series of motion models.

3. A motion estimation system as claimed in claim 2, wherein the motion models are polynomial motion models.

4. A motion estimation system as claimed in claim 2 or 3, wherein the series of motion models comprise a hierarchy inluding a translational motion model, a simplified linear model and a complete linear model.

5. A motion estimation system as claimed in any of claims 2 to 5, wherein the series of motion models comprises any one, or any combination of, a zero motion model, a translational motion model, an affine motion model and a quadratic motion model.

6. A motion estimation system as claimed in any preceding claim, wherein the series of motion estimators comprises a series of minimisers.

7. A motion estimation system as claimed in claim 6, wherein the series of minimisers comprises a segment matching minimiser, a Newton minimiser and a Quasi-Newton minimiser.

8. A motion estimation system as claimed in claim 6 or 7, wherein the series of minimisers comprises a full search minimiser and/or a Taylor expanded minimiser.

9. A motion estimation system as claimed in any preceding claim, further comprising means for smoothing the received frame and for forwarding the smoothed frame to the series of motion estimators.

10. A motion estimation system as claimed in claim 9, wherein the smoothing means comprises a series of low pass filters.

11. A motion estimation system as claimed in claim 9 or 10, wherein the control means selects the level of smoothing during minimisation depending on the change in prediction error.

12. A video coder comprising a motion estimation system as claimed in any preceding claim.

13. A motion estimation method for coding a video frame, comprising:

receiving a video frame to be coded;

estimating a motion vector field between the said received frame and a reference frame, using a motion estimator from a series of motion estimators of varying complexity;

determining whether a prediction error associated with the motion vector field estimated by the currently selected motion estimator exceeds a predetermined threshold and, only if so, selecting the subsequent motion estimator in the series.