Hierarchical hybrid shot change detection method for MPEG-compressed video

• US 20010021268A1
• Filed: 03/06/2001
• Published: 09/13/2001
• Est. Priority Date: 03/07/2000
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yoon, Kyoung Ro, Jun, Sung Bae
• Granted Patent: US 7,027,509 B2
• Time in Patent Office: Days
• US Class Current: 382/165
• CPC Class Codes: G11B 27/28 by using information signals recorded by the same method as the main recording G11B27/22 takes precedence
• CPC Class Codes: H04N 19/142 Detection of scene cut or scene change
• CPC Class Codes: H04N 19/179 the unit being a scene or a shot
• 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 19/87 involving scene cut or scene change detection in combination with video compression
• 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 21/44008 involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 5/147 Scene change detection
• CPC Class Codes: H04N 5/45 Picture in picture , e.g. displaying simultaneously another television channel in a region of the screen

Abstract

The present invention relates to a hierarchical hybrid shot change detection method in MPEG-compressed video circumstances, wherein the method according to the present invention comprises: detecting a shot change candidate region, by hierarchically applying a global color distribution difference among the frames by the color histogram; detecting an abridged shot change candidate region by using the difference of the global color histogram difference among adjacent I, P frames after additionally decoding P frames existed in the detected candidate region; decoding B frames within a abridged shot change detection candidate region at a macro block level in a sequence of the B frames sharing adjacent two anchor frames; determining a distribution characteristic of an intra coded block and a reference pattern type of each B frame in the region; and detecting a hard cut by using the distribution characteristic and reference type.

Claims

1. A hierarchical hybrid shot change detection method for MPEG-compressed video for detecting a shot change, by hierarchically applying a global color histogram based method and a macro block type distribution based method, comprising:

detecting a shot change candidate region by using the global color distribution difference among the frames by the color histogram;

detecting an abridged shot change candidate region by using the difference of the global color histogram among adjacent I/P, P/P, P/I frames after additionally decoding the P frames existed in the detected candidate region;

finding a distribution characteristic of an intra coded block and a reference type and a reference pattern of the each B frame by decoding the B frames in the detected abridged shot change candidate region at the macro block level; and

detecting a hard cut occurrence by using the distribution characteristic of the intra coded block and reference type and reference pattern.

2. The hierarchical hybrid shot change detection method for MPEG-compressed video according to

claim 1

, wherein the color histogram can be extracted by restoring a pixel value of the whole image or by restoring a DC image or by restoring a thumbnail image as a sub-sampling image.

3. The hierarchical hybrid shot change detection method for MPEG-compressed video according to

claim 1

, wherein the process for detecting the shot change candidate region is proceeded only when the difference of the global color distribution among the frames is bigger than a first threshold τ

_c1, and the process performs detection of the shot change candidate region for the next GOP (Group of Picture) region when the difference of the global color distribution among the frames is not bigger than the first threshold τ

_c1.

4. The hierarchical hybrid shot change detection method for MPEG-compressed video according to

claim 1

, wherein the process for detecting the shot change candidate region selects adjacent I frames as the two frames for calculating the difference of the color histograms.

5. The hierarchical hybrid shot change detection method for MPEG-compressed video according to

claim 1

, wherein the process for detecting the abridged shot change suspicious region comprises the steps of:

finding the difference of the global color histograms among the adjacent I/P, P/P, P/I frames by decoding the I, P frames in the detected shot change candidate region;

selecting a candidate region where the difference of the global color histograms is the maximum; and

selecting the pertinent region as the abridged shot change candidate region when the difference of the color histograms in the selected candidate region is bigger than a second threshold τ

_c2 or performing the shot change candidate detection for the next GOP region when the difference of the color histograms in the selected candidate region is not bigger than the second threshold τ

_c2.

6. The hierarchical hybrid shot change detection method for MPEG-compressed video according to

claim 5

, wherein the second threshold τ

_c2 can be a value same with the first threshold τ

_c1 for detecting the shot change candidate region on the basis of the difference of the global color histograms.

7. The hierarchical hybrid shot change detection method for MPEG-compressed video according to

claim 1

, wherein the process for detecting the abridged shot change suspicious region comprises the steps of:

calculating the difference of the global color histograms among the adjacent I/P, P/P, P/I frames by additionally decoding the P frames in the detected shot change candidate region;

detecting a peak by using a peak detection algorithm for the color histogram difference values; and

selecting the pertinent region as the abridged shot change candidate region when the gradient about the detected peak is bigger than a certain threshold or performing the shot change candidate detection about the next GOP region when the gradient about the detected peak is not bigger than the certain threshold.

8. The hierarchical hybrid shot change detection method for MPEG-compressed video according to

claim 7

, wherein the peak detection algorithm uses the gradient about the difference of the color histograms among the frames or calculates the peak ratio about an average of the difference of the color histograms among the frames.

9. A shot change detection method using a macro block type distribution characteristic in MPEG-compressed video environment, comprising:

decoding B frames in a shot change candidate region at a macro block level for a sequence of the B frames sharing adjacent two anchor frames;

determining a distribution characteristic of an intra coded block and a reference pattern type of the each B frame in the candidate region; and

detecting a hard cut by using the distribution characteristic of the intra coded macro blocks and reference type of macro blocks.

10. The shot change detection method using the macro block type distribution characteristic in MPEG-compressed video environment according to

claim 9

, wherein the process for decoding the B frames at the macro block level selects the B frame having the maximum ratio after calculating the ratio of the intra coded block at the each B frame, judges it as there is a hard cut when the ratio of the selected frame is bigger than a third threshold, and judges there is no hard cut when the ratio of the selected frame is not bigger than the third threshold.

11. The shot change detection method using the macro block type distribution characteristic in MPEG-compressed video environment according to

claim 9

, wherein the process for decoding the B frames at the macro block level adapts a peak detection algorithm about the calculated ratio after calculating the ratio of the intra coded block at the each B frame, judges it there is a hard cut when there is one peak in the suspicious region, and judges there is no hard cut when at least two peaks exist in the suspicious region.

12. The shot change detection method using the macro block type distribution characteristic in MPEG-compressed video environment according to

claim 9

, wherein the process for determining the reference pattern type of the B frame determines the reference type of the pertinent B frame as a forward reference pattern when a forward prediction ratio using two thresholds (τ

_u, τ

_d) is bigger than a fourth threshold (τ

_u), determines it as a none reference pattern when the forward prediction ratio is between the two thresholds (τ

_u, τ

_d), and determines it as a backward reference pattern when the forward prediction ratio using the two thresholds (τ

_u, τ

_d) is smaller than a fifth threshold (τ

_d).

13. The shot change detection method using the macro block type distribution characteristic in MPEG-compressed video environment according to

claim 9

, wherein the process for determining the reference pattern type of the B frames determines the first B frame in the candidate region as a hard cut point when the all reference pattern types are backward reference patterns, determines the first frame of the latter half as the hard cut point when the first half of the reference patterns of the B frames are the forward reference patterns and the latter half of the reference patterns of the B frames are the backward reference patterns, determines the last frame of the abridged candidate region as the hard cut point when the all reference pattern types are forward reference patterns, and determines there is no hard cut when the all above-described conditions are not satisfied.