Pulse or digital communications – Bandwidth reduction or expansion – Television or motion video signal
Reexamination Certificate
2000-07-28
2001-10-09
Le, Vu (Department: 2613)
Pulse or digital communications
Bandwidth reduction or expansion
Television or motion video signal
C375S240240, C348S699000
Reexamination Certificate
active
06301302
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a system designed to search for a desired scene represented by a moving picture signal. This invention also relates to a system for detecting a change in scenes (a scene change) represented by a moving picture signal. Furthermore, this invention relates to a recording medium which stores a computer-related video-signal processing program.
2. Description of the Related Art
Japanese published unexamined patent application 7-192003 discloses a system designed to search for a desired scene represented by a moving picture signal. In the system of Japanese application 7-192003, each sequence of 1-frame-corresponding segments which represent caption-added pictures is extracted from the moving picture signal. Typical scenes related to the respective extracted sequences can be indicated on a display. The user can search the indicated scenes for a desired scene.
The system of Japanese application 7-192003 implements a process of discriminating caption-added pictures from caption-less pictures. The system of Japanese application 7-192003 uses the assumption that pixels corresponding to edges of caption characters tend to remain at same positions during a given number of successive frames. For every frame, the number of such pixels is detected. When the number of such pixel exceeds a threshold number, it is decided that the related frame represents a caption-added picture. Otherwise, it is decided that the related frame represents a caption-less picture. The result of this decision tends to be adversely affected by noise in the moving picture signal.
According to a known method of detecting a change in scenes (a scene change) represented by a moving picture signal, every frame related to the moving picture signal is divided into a set of blocks having equal sizes. Detection is made as to differences (variations) in luminance or color between equal-position blocks in two successive frames. A given number of smaller differences are selected from among the detected differences. An inter-frame variation is calculated on the basis of the summation of the smaller differences. When the inter-frame variation exceeds a threshold value, it is decided that a scene change occurs between the two successive frames.
Japanese published unexamined patent application 4-111181 discloses a method of detecting a change point in a moving picture. According to the method in Japanese application 4-111181, every frame related to the moving picture is divided into a set of blocks having equal sizes. Color-related feature quantities are calculated for the respective blocks. Calculation is given of differences (variations) in color-related feature quantity between equal-position blocks in two successive frames. Blocks related to differences greater than a threshold value are regarded as effective-change blocks. A correlation coefficient for the last two frames is calculated on the basis of the number of the effective-change blocks. In addition, calculation is made as to the rate of a change between the present correlation coefficient and the immediately preceding correlation coefficient. When the calculated change rate exceeds a prescribed value, it is decided that a change point occurs in the moving picture.
SUMMARY OF THE INVENTION
It is a first object of this invention to provide an improved apparatus designed to search for a desired scene represented by a moving picture signal.
It is a second object of this invention to provide an improved method of searching for a desired scene represented by a moving picture signal.
It is a third object of this invention to provide an improved apparatus for detecting a change in scenes (a scene change) represented by a moving picture signal.
It is a fourth object of this invention to provide an improved method of detecting a change in scenes (a scene change) represented by a moving picture signal.
It is a fifth object of this invention to provide a recording medium which stores an improved video-signal processing program.
A first aspect of this invention provides a moving picture search apparatus comprising first means for dividing every frame represented by a moving picture signal into blocks; second means for calculating a number of pixels forming portions of a caption in each of the blocks; third means for comparing the number of pixels which is calculated by the second means with a threshold value; fourth means for, when the calculated number of pixels is equal to or greater than the threshold value, deciding that the related block is a caption-containing block; fifth means for detecting a time interval related to the moving picture signal during which every frame represented by the moving picture signal has a caption-containing block decided by the fourth means; and sixth means for selecting a 1-frame-corresponding segment of the moving picture signal which represents a caption-added frame present in the time interval detected by the fifth means.
A second aspect of this invention is based on the first aspect thereof, and provides a moving picture search apparatus wherein the second means comprises means for detecting a luminance level of each of pixels composing a block, means for comparing the detected luminance level with a threshold level, and means for, when the detected luminance level is equal to or greater than the threshold level, deciding that the related pixel forms a portion of a caption.
A third aspect of this invention is based on the first aspect thereof, and provides a moving picture search apparatus wherein the second means comprises means for detecting a luminance level of each of pixels composing a block, means for comparing the detected luminance level with a threshold level, means for calculating a difference between the detected luminance level of each of pixels and the detected luminance level of a neighboring pixel, means for comparing the calculated difference with a threshold difference, and means for, when the detected luminance level is equal to or greater than the threshold level and the calculated difference is equal to or greater than the threshold difference, deciding that the related pixel forms a portion of a caption.
A fourth aspect of this invention is based on the first aspect thereof, and provides a moving picture search apparatus wherein the second means comprises means for detecting a color of each of pixels composing a block, means for comparing the detected color with a reference color range, and means for, when the detected color is in the reference color range, deciding that the related pixel forms a portion of a caption.
A fifth aspect of this invention is based on the first aspect thereof, and provides a moving picture search apparatus wherein the second means comprises means for detecting a color of each of pixels composing a block, means for comparing the detected color with a reference color range, means for calculating a difference between the detected color of each of pixels and the detected color of a neighboring pixel, means for comparing the calculated difference with a reference difference, and means for, when the detected color is in the reference color range and the calculated difference is in the reference difference, deciding that the related pixel forms a portion of a caption.
A sixth aspect of this invention is based on the first aspect thereof, and provides a moving picture search apparatus wherein the fourth means comprises means for comparing the calculated number of pixels in a block in a present frame with a second threshold value, means for comparing the calculated number of pixels in the block in a previous frame with the second threshold value, means for calculating an absolute value of a difference between the calculated number of pixels in the block in the present frame and the calculated number of pixels in the block in the previous frame, means for comparing the calculated absolute value of the difference with a third threshold value, and means for, when both the calculated number of pixels in the block in the present fra
Kikuchi Yasuhiro
Tanaka Akiyoshi
Yamada Shin
Connolly Bove Lodge & Hutz
Le Vu
Matsushita Electric - Industrial Co., Ltd.
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