Image analysis – Image compression or coding – Interframe coding
Reexamination Certificate
2000-07-26
2001-07-03
Patel, Jay (Department: 2623)
Image analysis
Image compression or coding
Interframe coding
C348S700000, C382S278000
Reexamination Certificate
active
06256419
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a video edit system and a video browsing method which are capable of locating the head of each video or movie shot, included in a video having a plurality of video or movie shots, wherein each video or movie shot includes a series of uninterrupted video images photographed by one camera. More particularly, the present invention relates to a method and apparatus for detecting a point of change between video shots from a video stored on a video tape or video disk, wherein the video includes a plurality of succeeding frames.
With computer operation speed growing faster and the capacity of memory increasing in recent years, attention is now being focused on database systems and presentation tools which can handle movie and video information. Such information can not be sufficiently handled with conventional systems. Searching for only a desired part of a vast amount of video information and editing it is a time-consuming work.
Among the methods to alleviate editing work by using a computer a method disclosed in “Automatic Video Indexing and Full-Video Search for Object Appearances,” Joho Shori Gakkai Ronbunshi (Collection of Papers, published by Information Processing Society), Vol. 33, No. 4, and Japan Patent Laid-Open No. 111181/1992 entitled “Change Point Detection Method in a Video” has been proposed. The above disclosed method involves automatically dividing a video for individual shots, preparing a list of images each representing a shot, and using them like indices of a book to aid in searching and editing of the video. The above disclosed method allows one to grasp the contents of a video at a glance using the list and to locate a desired scene. It is also possible to handle the video in units of a shot, which is an appropriate length for handling, and thereby make rough editing easy.
To divide the video into shots requires detecting a point of change between video shots in a video, i.e., a change in appearance of a first video shot relative to a second video shot. A conventional method of detecting a point of change between video shots in a video, as described in the above-mentioned Japan Patent Laid-Open No. 111181/1992, is based on a technique that decides that there is a point of change between video shots, i.e., a change in appearance between two succeeding frames of a video (frames are still images making up the motion picture wherein in television
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images are displayed in each second) when there is an image difference between the two frames.
The above disclosed method, however, has a drawback in that it picks up as a point of change video shots having instantaneous disturbances of an image caused by strobe flashes produced when photographs are taken. These disturbances are such as those frequently encountered in press conferences, and by equipment trouble. Such image disturbances tend to occur successively during one shot, resulting in unwanted division of one shot. In a period of a video in which generally dark images of a night scene continue, the image difference between succeeding frames tends to be smaller than that of bright scenes. Hence, if the same reference is used for both dark scenes and bright scenes in determining a point of change, bright scenes may induce an overly sensitive reaction resulting in an erroneous detection of the point of change, while in dark scenes the point of change may fail to be detected.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a method and apparatus to detect a point of change between video shots from a video consisting of a plurality of succeeding frames.
Another object of the present invention is to provide a method and apparatus to detect a point of change between video shots from a video in such a manner to prevent erroneous detection of a point of change between video shots from a video due to an instantaneous image disturbance.
Yet another object of the present invention is to provide a method and apparatus to detect a point of change between video shots from a video without degrading the detection sensitivity below that of the conventional technique.
Still yet another object of the present invention is to provide a method and apparatus to detect a point of change between video shots from a video that can respond flexibly to a change in characteristics of the video.
To achieve the above-described objects, the present invention provides a method having the steps of inputting a video chronologically one frame at a time into a processing device, calculating a feature quantity of video image data for each frame, determining a correlation coefficient between the feature quantity of a current frame and the feature quantity of an immediately preceding frame, determining a second correlation coefficient between the feature quality of the current frame and a feature quality of at least two frames preceding the current frame and indicating a point of change between video shots when the first correlation coefficient and the second correlation coefficient are out of predetermined allowable ranges.
To further achieve the above-described objects the present invention provides a system for detecting a point of change between video shots from a video consisting of a plurality of succeeding frames. The system includes video playback apparatus for playing a video chronologically one frame at a time, a display for displaying the video, and a processing device for calculating a feature quantity of video image data for each frame, determining a first correlation coefficient between a feature quantity of a current frame and a feature quantity calculated from an immediately preceding frame, determining a second correlation coefficient between the feature quantity of the current frame and a feature quantity of at least two frames preceding the current frame, and indicating on the display a point of change between video shots when the first correlation coefficient and the second correlation coefficient are out of predetermined allowable ranges.
The present invention also provides a computer program product for use with a computer having a display. The computer when executing the computer program detects a point of change between video shots from a video consisting of a plurality of succeeding frames. The computer program includes a computer readable medium with the computer program recorded thereon. The computer program includes a first code section for inputting a video chronologically one frame at a time into a processing device, a second code section for calculating a feature quantity of video image data for each frame, a third code section for determining a first correlation coefficient between a feature quantity of a current frame and a feature quantity calculated from an immediately preceding frame and determining a second correlation coefficient between the feature quantity of the current frame and a feature quantity of at least two frames preceding the current frame, and a fourth code section for indicating a point of change between video shots when the first correlation coefficient and the second correlation coefficient are out of predetermined allowable ranges.
When there is an instantaneous image disturbance, there is a characteristic that an image difference between a disturbed frame and an immediately preceding or following frame is larger than an image difference between two frames having the disturbed frame between them. Thus, according to the present invention, when a pattern of combination of correlation coefficients representing such a state is detected, it is possible to correctly decide that the detected change is not a true point of change between video shots. Conversely, it is possible to detect only the part where such an image disturbance has occurred. Further, by dynamically changing the threshold for detecting the point of change between video shots according to the feature of the immediately preceding frame, it is possible to make a precise decision, according to the features of the video image, on whether or not the object
Fujita Takehiro
Miyatake Takafumi
Nagasaka Akio
Nagaya Shigeki
Tanaka Kazuaki
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Patel Jay
LandOfFree
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