Method for evaluating video quality

• US 20110206298A1
• Filed: 02/14/2011
• Published: 08/25/2011
• Est. Priority Date: 02/23/2010
• Status: Active Grant

• Current Assignee: Thomson Licensing (Vantiva SA)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Weitbruch, Sébastien, Robert, Arnaud, Mueller, Stefan
• Granted Patent: US 8,670,627 B2
• Time in Patent Office: Days
• US Class Current: 382/309
• CPC Class Codes: H04N 17/004 for digital television systems

Abstract

A method for evaluating video quality of a video stream comprising the steps of

• a) calculating, for at least a first frame of a series of frames from said video stream, a true value of at least one video quality-related parameter associated to said first frame;
• b) calculating a predicted value of said video quality-related parameter for at least a second frame from said series of frames based on said true value associated to said first frame;
• c) calculating a true value of said video quality-related parameter associated to said second frame; and
• d) judging the video quality of said second frame based on a difference between true and predicted values of the at least one video quality-related parameter associated to said second frame.

Claims

1. A method for evaluating video quality of a video stream comprising the steps of

a) calculating, for at least a first frame of a series of frames from said video stream, a true value of at least one video quality-related parameter associated with said first frame;

b) calculating a predicted value of said video quality-related parameter for at least a second frame out of said series of frames, the prediction being based on said true value associated with said first frame;

c) calculating a true value of said video quality-related parameter associated with said second frame; and

d) judging the video quality of said second frame based on a difference between true and predicted values of the at least one video quality-related parameter associated with said second frame.

2. The method of claim 1 wherein said predicted value is calculated using a Kalman filter.

3. The method of claim 1, wherein steps b), c) and d) are iterated, and a frame used as a second frame in one of said iterations is used as one of said first frames in a subsequent iteration.

4. The method of claim 1, wherein the second frame is a successor of said at least one first frame in said series of frames.

5. The method of claim 1, wherein the second frame is a predecessor of said at least one first frame in said series of frames.

6. The method of claim 1, wherein said at least one video quality related parameter comprises one of

contrast,

edge contrast ratio,

histogram difference, or

noise intensity.

7. The method of claim 1, wherein steps a) to c) are carried out for a plurality of video quality-related parameters, and the judging step d) is based on the differences between true and predicted values of all said parameters.

8. The method of claim 7, wherein step d) comprises the steps of

normalizing said differences and

calculating a sum based on said normalized differences.

9. The method of claim 1, wherein the judgment of step d) is carried out only if at least ten first frames are available for calculating the predicted value in step b).

10. The method of claim 1, wherein in step d) the second frame is provisionally judged to be defective if said difference or said sum exceeds a predetermined threshold.

11. A method for evaluating video quality of a video stream comprising the steps of

aa) defining a first series of frames and a second series of frames;

bb) calculating, for at least a first frame of the first series of frames from said video stream, a true value of at least one video quality-related parameter associated with said first frame;

cc) calculating a predicted value of said video quality-related parameter for at least a second frame out of said first series of frames, the prediction being based on said true value associated with said first frame;

dd) calculating a true value of said video quality-related parameter associated with said second frame;

ee) provisionally judging the video quality of said second frame to be defective if a difference between true and predicted values of the at least one video quality-related parameter associated with said second frame exceeds a predetermined value;

ff) calculating, for at least a first frame of the second series of frames from said video stream, a true value of at least one video quality-related parameter associated with said first frame;

gg) calculating a predicted value of said video quality-related parameter for at least a second frame out of said second series of frames, the prediction being based on said true value associated with said first frame;

hh) calculating a true value of said video quality-related parameter associated with said second frame;

jj) provisionally judging the video quality of said second frame to be defective if a difference between true and predicted values of the at least one video quality-related parameter associated with said second frame exceeds a predetermined value;

wherein a frame belonging to said first and second series is definitely judged to be defective if it was provisionally judged to be defective in step ee) and in step jj).