Apply GPCA to Motion Segmentation - Intelligent Video Event Analysis and Understanding - page 33

frame 1 frame 2 1. background 2. phone regions
3. head region 4. background 5. phone regions 6. head region
7. Occluded region
Fig. 5 The segmentation of the Susie calling. 1)-3) are the results of the subspace segmenta-
tion method; 4)-6) are the results of the post-processing procedure; 7) the layer boundary
goes through the occluded regions.
Moreover, it has been judged that the regions of the phone and the hair patch are
in front of the head region. This seems to be a bit strange. In general, the hair
patch belongs to the head region. All the hair should be regarded as a whole body
on the head and there is no occlusion to each other (unless the hairlines are con-
sidered). But it can be observed that the occluded regions overlying on the layer
boundary appear at the bottom right of the image, i.e. around the boundaries be-
tween the shoulder and the hair. The motion of the hair is independent of that of
the shoulder. The shoulder region is classified into the head region. Thus, it is
acceptable to preserve this patch as an independent layer as shown in Fig.5(5).
Table Tennis
The table tennis sequence presents a hand holding a table tennis racket to hit a
white ball. The image resolution is 190×130 pixels. Applying our motion segmen-
tation method to the two successive frames, we obtained 3 segmented parts of the
scene, i.e. ball region, arm region and background region, as shown in Fig.6. The
segmentation results by the subspace segmentation approach described in section
2 are shown in Fig.6(1-3). After the post-processing procedure, the segmentation
results are shown in Fig.6(4-6), and the region of background is behind those of
the ball and arm.
It can be observed that the region of the ball is very small compared to that of
the background. In terms of the area comparison strategy, it should be merged into
the background. But due to the detected layer edge segments by the Polysegment
Alg. in step 3 of the post-processing procedure, the ball region can be preserved.