Method and apparatus for motion detection from compressed video sequence

• US 20030112866A1
• Filed: 12/18/2001
• Published: 06/19/2003
• Est. Priority Date: 12/18/2001
• Status: Abandoned Application

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Yu, Shan, Steward, Daniel
• Application Number:
  US10/024,886
• Publication Number:
  US 20030112866A1
• Time in Patent Office: Days
• US Class Current: 375/240.03
• CPC Class Codes: H04N 19/196 being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters processing of motion vectors H04N19/513
• CPC Class Codes: H04N 19/198 including smoothing of a sequence of encoding parameters, e.g. by averaging, by choice of the maximum, minimum or median value
• CPC Class Codes: H04N 19/48 using compressed domain processing techniques other than decoding, e.g. modification of transform coefficients, variable length coding [VLC] data or run-length data motion estimation in a transform domain H04N19/547; processing of decoded motion vectors H04N19/513
• CPC Class Codes: H04N 19/503 involving temporal prediction adaptive coding with adaptive selection between spatial and temporal predictive coding H04N19/107; adaptive coding with adaptive selection among a plurality of temporal predictive coding modes H04N19/109
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/90 using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals
• CPC Class Codes: H04N 7/188 Capturing isolated or intermittent images triggered by the occurrence of a predetermined event, e.g. an object reaching a predetermined position signal generation from motion picture films H04N5/253

Abstract

A receiver locates command data from the compressed video sequence. A detector detects a change in the command data to indicate motion. The detector detects change in the quantization factor to indicate motion according to an embodiment. The receiver locates the command data from the compressed video sequence by obtaining synchronization information to locate known position in the video sequence and by parsing until finding the desired command data field according to an embodiment. This command data located by the receiver indicates the quantization factor of the compressed video sequence. Both the receiver and the detector can operate in real time on the compressed video sequence.

Claims

1. An apparatus for motion detection on a compressed video sequence, comprising:

a receiver for locating command data from the compressed video sequence; and

a detector for detecting a change in the command data to indicate motion.

2. An apparatus for motion detection according to claim 1,

wherein the compressed video sequence received by the receiver has predetermined compressed format;

and

wherein the receiver locates the command data from the compressed video sequence by obtaining synchronization information to locate known position in the video sequence and by parsing the compressed video sequence until finding the desired command data field.

3. An apparatus for motion detection according to claim 1,

wherein the command data located by the receiver comprises a quantization factor of the compressed video sequence;

and

wherein the detector detects change in the quantization factor to indicate motion.

4. An apparatus for motion detection according to claim 3, wherein the compressed video sequence received by the receiver comprises frames of digital command data and of image data.

5. An apparatus for motion detection according to claim 4, wherein the compressed video sequence received by the receiver has a constant number of bits per frame.

6. An apparatus for motion detection according to claim 3, wherein the detector detects change in the quantization factor by assessing an amount of change of a present value T_i and a previous value T_i-1 as follows:

amount of change=(T_i−

T_i-1)/T_i

and wherein the amount of change is threshold to indicate motion.

7. An apparatus for motion detection according to claim 6, wherein the detector detects an amount of change by thresholding to indicate motion when the amount of quantization factor change is above about 20%.

8. An apparatus for motion detection according to claim 6, wherein the detector detects an amount of change by thresholding to indicate motion when the amount of quantization factor change is above between approximately 10% and 90%.

9. An apparatus for motion detection according to claim 3, wherein the detector detects an amount of change in the quantization factor by taking a derivative of the quantization factor to assess an amount of change and indicate motion.

10. An apparatus for motion detection according to claim 3, wherein the compressed video sequence received by the receiver comprises an MPEG compressed video sequence.

11. An apparatus for motion detection according to claim 3, wherein the compressed video sequence received by the receiver comprises an H.263 compressed video sequence.

12. An apparatus for motion detection according to claim 11, wherein the command data located by the receiver comprises a PQUANT quantization factor field of the H.263 compressed video sequence.

13. An apparatus for motion detection according to claim 1, wherein both the receiver and the detector operate in real time on the compressed video sequence.

14. A method of motion detection on a compressed video sequence, comprising the steps of:

(a) locating command data from the compressed video sequence; and

(b) detecting a change in the command data to indicate motion.

15. A method of motion detection according to claim 14,

wherein the video sequence used in step (a) has predetermined format;

and

wherein the receiving of said step (a) comprises the substeps of

(a1) obtaining synchronization information to locate known position in the video sequence; and

(a2) parsing the compressed video sequence until finding the desired command data field.

16. A method of motion detection according to claim 14,

wherein the command data located in step (a) comprises a quantization factor of the compressed video sequence;

and

wherein the detecting step (b) comprises the substep of (b1) detecting change in the quantization factor to indicate motion.

17. A method of motion detection according to claim 16, wherein the compressed video sequence used in step (a) comprises frames of digital command data and of image data.

18. A method of motion detection according to claim 17, wherein the compressed video sequence used in step (a) has a constant number of bits per frame.

19. A method of motion detection according to claim 16, wherein the step (b1) of determining change in the quantization factor comprises the substep of (b1i) taking a derivative of the quantization factor to assess an amount of change and indicate motion.

20. A method of motion detection according to claim 14, wherein both the steps (a) and (b) operate in real time on the compressed video sequence.