Methods of scene change detection and fade detection for indexing of video sequences

DETAILED DESCRIPTION DESCRIPTION OF THE PREFERRED EMBODIMENT.
Referring to the schematic diagram of FIG.
1 of the drawing, it can be seen that methods according to a first aspect of the present invention make use of a preliminary step which involves locating suspected scene changes using only I-frame information in the compressed domain (block 20 of the diagram).
This step relies upon use of DC image-based criteria to "qualify" certain pairs of frames as indicating gradual or abrupt scene changes.
Thereafter, the qualified frame associated information is further processed to locate abrupt and/or fade-in, fade-out scene changes using either a bit allocation distribution criterion across P-frames (block 30) or a criterion comparing the number of positive/negative DC residual coefficients (block 40) with respect to each P-frame in the regions where there is a suspected scene or object change.
In this manner, temporal segmentation markers may be generated and are associated with the input video sequence to locate and identify the particular types of scene changes of the video sequence.
Specific preferred arrangements for each of the abrupt scene change and fade-in/fade-out scene change detection steps will now be described in detail.
It should be appreciated that there is substantial opportunity for varying details of these steps without departing from the more general aspects of the present invention.
Detailed method steps are, however, indicated below to provide an appreciation for the possible variations to persons skilled in this art.
Simply stated, one aspect of the present method comprises the following steps: 1.
Locate the GOP's in which scene changes are suspected to exist by using the DC--image-based process on successive I-frames; 2.
Apply the bit allocation-based criterion to P-frames in each of the GOP's selected in step 1 to locate cut points.
To apply this latter technique to MPEG-4 compressed video, the following detailed steps are employed.
Since MPEG-4 is object-based, similarly located objects in two adjacent frames are compared