Video retrieval method and apparatus

#The present invention relates to a method, and apparatus, for retrieving a broadcast video or a video included in a data base, and in particular to a video retrieval method, and apparatus, capable of retrieving a video at high speed by using a feature of a video as a clue.

#In multimedia information processing systems of recent years, it is possible to store various kinds of information such as videos and texts and display them to users. In case they are to be retrieved, however, there is no alternative but to retrieve them by using languages such as keywords. In this case, work for providing key words is required. The task of providing frames of a video with respective keywords requires much hard labor. Furthermore, since keywords are freely provided by the data base constructor, there is a problem that these keywords become useless in case the viewpoint of the user is different from that of the data base constructor. Furthermore, in case of videos, there is a need for retrieval based upon a feature of an image itself besides a keyword. Retrieval using a feature of an image as a clue needs a technique capable of fast matching a feature of a video including an enormous number of frames with features of its enquiry video. Heretofore, there has never been a matching technique which can be applied to videos. In conventional video retrieval, therefore, there is no practical means except a method in which the user checks and looks for a video with eyes while reproducing videos together with functions of rapid traverse and rewind. Even if videos are digitized and stored to form a data base, therefore, efficient use is impossible. Furthermore, there exists no vodeo retrieval system catching a specific scene out of a video which is being broadcasted.

#An object of the present invention is to provide a video retrieval method, and apparatus, capable of fast matching a feature of a target video with a feature of an enquiry video without conducting work of providing keywords for video retrieval. As for the target video, both a video which is being broadcasted and a video included in a data base should be dealt with.

#FIG. 1 is a schematic block diagram of a video retrieval system configuration in an embodiment of the present invention;

#FIG. 2 is an entire block diagram of an embodiment of video retrieval processing according to the present invention;

#FIG. 3 is a diagram showing an embodiment of a video naming method using a character string;

#Hereafter, an embodiment of the present invention will be described by referring to drawings.

#FIG. 1 is an example of a schematic block diagram of a system configuration for implementing the present invention. Numeral 1 denotes a display device such as a CRT for displaying an output screen of a computer 2. Instructions to the computer 2 can be given by using a pointing device 3 or a keyboard 4. A video reproducing device 5 is an optical disk or a video deck. Video signals outputted from the video reproducing device 5 are successively converted to digital image data by a video input device 6 and sent to the computer 2. When occasion demands, it is also possible to take in video images which are being broadcasted and a video signal fed from a broadcast receiver 7 is inputted to the video input device 6. Within the computer 2, digital image data are inputted to a memory 9 via an interface 8 and processed by a CPU 10 in accordance with a program stored in the memory 9. In case the video handled by the CPU 10 is being sent from the video reproducing device 5, frame images are provided with numbers (frame numbers) in order from the head of the video. By sending a frame number to the video reproducing device via a control line 11, the video of the pertinent scene is reproduced. In case of a video sent from the broadcast receiver 7, there are no frame numbers. As occasion demands in this case, therefore, time when an image has been taken in is recorded and used instead of frame number. Under the necessity of internal processing of the computer, various kinds of information can be stored in an external information storage device 12. In the memory 9, various data produced by processing described hereafter are stored. The various data stored in the memory 9 are referred to as occasion demands.

#FIG. 2 is an entire block diagram of an embodiment of video retrieval processing according to the present invention. The processing is executed within the computer 2. In accordance with the present invention, the target video is inputted frame by frame successively and stored temporarily in the memory 9. The representative frame extractor 20 detects a scene change from a frame image 27 stored in the memory 9 by referring to preceding and succeeding frame images and extracts a frame image 28 at the time of detection. The character string converter 21 converts the frame image 28 to a character code string 29 reflecting a feature of the frame image 28. The video name generator 22 successively stores the character code string sent from the character string converter 21 in a shift register having a fixed length. The character code string stored in the shift register corresponds to a frame image string forming the video, and the character code string is outputted as a video name 30.