Feature scene detecting method and apparatus, and storage medium containing processing program therefor

Abstract: According to the invention, a technique to enable feature scene detection over a plurality of sequential streams. A feature scene detection method for detecting a specific feature scene included in a video image, comprises a step of detecting feature scenes included in a video image divided and recorded in a plurality of sequential streams with time information indicative of replay time of the feature scenes, and a step of, on the assumption that the time information of the detected feature scenes are consecutive in the plurality of sequential streams, obtaining a detection frequency of the feature scenes per unit period, and classifying and recording a specific group of feature scenes with a detection frequency equal to or greater than a threshold value.

Description: The present invention relates generally to techniques for detecting feature scenes included in a video image, and more particularly to methods, apparatus and computer programs for detecting specific feature scenes within a video image, that has been divided and recorded in a plurality of sequential streams. European patent application EP 1 006 685 A2 discloses a method and apparatus for processing a television signal, and for detecting the presence of commercials in the television signal. A commercial candidate section detector detects a commercial candidate section on the basis of a quiet section and a scene charge point. A commercial characteristic quantity detector judges whether the commercial candidate section has various characteristics of commercial, and adds a predetermined value to a commercial characteristic value on the basis of the judgment result. With rapid development of television technologies and direction techniques, special effects, such as flashing lights and abrupt scene changes, in animation programs and the like, occasionally impair health of some viewers. Image flickering, intermittent images, rapid color changes and the like have been found to induce health problems in individuals suffering from photosensitive epilepsy, for example. The Independent Television Commission (hereinafter "ITC"), working in conjunction with medical experts and television licensees, has proposed a set of guidelines for reducing the risk of exposure to potentially harmful stimuli from television viewing. Television images are refreshed a number of times each second and interlaced scanning can generate harmful image flicker. According to the ITC guidelines, flashing and flickering images in black and white which result in visible screen brightness changes of more than 10% of the viewing screen area at rates exceeding 3 flashes per second should be avoided. Moderate brightness level changes in up to 10% of the viewing screen are acceptable to the ITC, as are repetitive changes in screen brightness not exceeding 10% between any two consecutive image frames. The ITC finds flashes of highly saturated red color particularly hazardous, and recommends that such flashes be avoided. For a more detailed description of the ITC guidelines, reference may be had to section 7 of the "ITC Guidance Note on Flashing Images and Regular Patterns," which is available from the ITC web site, at http://www.itc.org.uk. which is incorporated herein by reference. Picture editing techniques that can be used to determine likely sources of flickering images exist, however opportunities for further efficiencies are present. What is needed are improved techniques for detecting special effects in video streams. Preferably, the present invention has an object to provide a technique to reduce the above problems and enable detection of feature scene over a plurality of sequential streams. Preferably, another object of the present invention is to provide a technique to enable an operator to replay a feature scene without being adversely effected by the feature scene when the feature scene is checked. According to the present invention, techniques for detecting feature scenes within a sequential streams of video are provided. Embodiments can include a detecting apparatus that detects specific feature scenes included in a video image. The video image can be divided and recorded in a plurality of sequential streams, and the like. Further, the video image may be divided such that one or more one feature scenes is divided between any two of the plurality of sequential streams. Techniques according to the invention are sufficiently robust to treat a'plurality of sequential streams as a continuous video image for the purposes of feature scene detection. In a representative embodiment according to the present invention, a method for detecting a specific feature scene in a video image is provided. The video image may be divided and recorded into a plurality of sequential streams, for example. The video image can comprise time information indicative of a replay time of the feature scenes, and the like. The method can include, for example, searching one or more frames comprising the video image for feature scenes. If a feature scene is located, information about the feature scene can be stored into a list, for example. Computing a detection frequency of the feature scenes per unit time period can also be part of the method. Further, the method can include classifying a specific group of feature scenes having a detection frequency equal to or greater than a threshold value. When a particular feature scene is divided across multiple sequential input streams, the method can determine that divided portions of the particular feature scene comprise one feature scene based upon the time information corresponding to frames within the video image. In a further representative embodiment according to the present invention, a method for detecting a specific feature scene in a video image can search the video image for feature scenes by capturing a frame image and a corresponding time code. A feature amount can be computed for the captured frame image. The method can also include determining based upon the feature amount whether the frame image is a feature scene, and if so, storing information about the feature scene into a first list, for example. The method can also repeat the capturing, computing and determining for subsequent frame images. In a yet further representative embodiment according to the present invention, a method for detecting a specific feature scene in a video image can compute a detection frequency of the feature scenes per unit time period by determining a number of feature scenes detected, based upon the information about the feature scene stored into the first list, for example. The method can determine a time period from the time information corresponding to the detected feature scenes in the plurality of sequential streams; and compute the detection frequency of the feature scenes per unit time period from the number of feature scenes detected and the time period. In a still further representative embodiment according to the present invention, a method for detecting a specific feature scene in a video image can classify feature scenes by selecting from the feature scenes groups of feature scenes having a number of feature scenes detected per unit time period equal to or greater than a threshold value; and thereupon store the selected groups of features scenes into a second list, for example. Further, the method can also include obtaining a specific group of feature scenes having a detection frequency per unit period equal to or greater than a threshold value from among feature scenes included in a video image. Then the obtained specific group of feature scenes can be replayed using a replay technique to reduce a health risk to a viewer. For example, in some specific embodiments, the replay technique to reduce a health risk to a viewer further can be a technique of replaying the feature scenes at a slower than normal rate, for example. Another technique is to replay the feature scenes using a color substituted for red. Other such techniques can also be used without departing from the spirit and scope of the present invention. In a representative embodiment according to the present invention, a computer program product for detecting a specific feature scene in a video image is provided. The video image can be divided into portions, with each portion recorded into two or more sequential streams. The video image can have time information indicative of replay time of the feature scenes, for example. The computer program product comprises code that searches one or more frames comprising the video image for feature scenes, and if a feature scene is located, stores information about the feature scene into a first list, for example. The program product can also include code that computes a detection frequency of the feature scenes per unit time period; and code that classifies a specific group of feature scenes having a detection frequency equal to or greater than a threshold value. The program product further includes a computer readable storage medium for holding the code. Numerous benefits are achieved by way of the present invention over conventional techniques. According to a specific embodiment of the present invention, as a specific group of feature scenes is replayed using a replay technique that is different from a normal replay techniques, so that when the feature scene is checked, the replaying does not cause harmful effects to an operator performing the checking. According to a specific embodiment of the present invention, as feature scene detection is performed while a video image divided and recorded in a plurality of sequential streams is handled as a continuous video image, feature scene detection over a plurality of sequential streams can be performed. These and other benefits are described throughout the present specification. A further understanding of the nature and advantages of the invention herein may be realized by reference to the remaining portions of the specification and the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 illustrates a diagram showing a representative system configuration of the feature scene detecting apparatus in a specific embodiment according to the present invention. Fig. 2 illustrates a flowchart showing a representative feature scene detection processing in a specific embodiment according to the present invention. Fig. 3 illustrates a diagram showing a representative data structure of data upon detection in a specific embodiment according to the present invention. Fig. 4 illustrates a diagram showing a representative data structure after the completion of the detection processing in a specific embodiment according to the present invention. Fig. 5 illustrates a diagram showing a representative user interface of the feature scene detecting apparatus in a specific embodiment according to the present invention. Fig. 6 illustrates a diagram showing a representative correspondence between video images and results of the feature scene detection processing in a specific embodiment according to the present invention. Fig. 7 illustrates a diagram showing a representative display of a total period of all the video images in the feature scene detecting apparatus in a specific embodiment according to the present invention. Fig. 8 illustrates a diagram showing a representative display of roll number and time code in the roll in the feature scene detecting apparatus in a specific embodiment according to the present invention. Fig. 9 illustrates a flowchart showing a representative video replay processing in a specific embodiment according to the present invention. Fig. 10 illustrates a diagram showing an overview of color information change in a specific embodiment according to the present invention. Fig. 11 illustrates a diagram showing an overview of slow feature scene replay in a specific embodiment according to the present invention. DESCRIPTION OF THE SPECIFIC EMBODIMENTS The present invention provides techniques for feature scene detecting, including a feature scene detection apparatus, and a method for detecting a specific feature scenes included in a video image. The techniques according to the present invention can detect feature scenes in which a video image has been divided and recorded into a plurality of sequential streams analogous to a continuous video image. In one technique for detecting a feature scene, special effects are detected using a device. The device detects a video image part (feature scene), corresponding to a condition previously designated in the detection device, from a detection object video image, and outputs the result of detection , i.e., respective detected video image frames, detected time and the like, to a monitor, a printer or the like connected to the device. For further description of one example of such a device, reference may be had to, "Hohsoh Gijutsu 1998 VOL. 51 NO. 9 Special Issue II: Flashing Video Image Detection in Animation Program," which is incorporated herein in its entirety for all purposes. In conventional picture editing techniques, video image is held in a single source stream, for example, making detection processing of a plurality of video image parts included in a plurality of sequential streams as one video image unavailable. Accordingly, at the initial stage of video image formation, if a special effect, such as flashing light, for example, is present, but is split into components existing in a plurality of sequential streams, conventional techniques cannot determine whether the special effect corresponds to a previously-designated condition. Further, when many conventional techniques check a special effect, the checking process might pose a risk for a user performing the checking. According to the present invention, feature scenes can be detected in a video image that has been divided and recorded into a plurality of sequential streams so that feature scene information is included in each video image in each stream. Specific embodiments according to the invention can detect such features scenes using time information, such as time code indicative of replay time of the feature scene, for example. In a representative embodiment according to the present invention, the time information of the detected feature scenes is consecutive in a plurality of sequential streams. A detection frequency of the feature scenes per unit period is obtained. For example, in a case where a plurality of feature scenes are detected from the end of the first sequential stream to the beginning (hereinafter "head") of the second sequential stream, based upon the time codes of these scenes being consecutive, the number of feature scenes per unit period is calculated from the end of the first sequential stream to the head of the second sequential stream, thus the detection frequency is obtained. Then, the scenes with the obtained detection frequency equal to or greater than a threshold value are classified and recorded as a specific group of feature scenes (hereinafter "group"). Further, when the content of the classified group of specific feature scenes is checked, video images of the classified group of specific feature scenes are obtained from the plurality of sequential streams. Then, the obtained group of specific feature scenes are replayed by a replay technique different from a normal replay technique. The replay technique can be selected to reduce health risks to an operator, for example. For example, a replay technique using a color different from that of the color used in the scene or using a speed lower than a normal speed. As the feature scene detecting apparatus of the present invention performs feature scene detection while regarding a video image divided and recorded in a plurality of sequential streams as a continuous video image, it can detect a feature scene split over sequential stream boundary in a plurality of sequential streams. A feature scene detecting apparatus according to a representative embodiment of the present invention will be described. The described embodiment can perform feature scene detection and is capable of processing a video image divided and recorded in a plurality of sequential streams as a continuous video image. Fig. 1 shows a system configuration of a feature scene detecting apparatus 100 in a representative embodiment according to the present invention. As shown in Fig. 1, the feature scene detecting apparatus 100 has a CPU 101, a memory 102, an auxiliary memory device 103, a display device 104, a keyboard 105, a mouse 106, a video input device 107, an interface 108 and a video replay device 109. The CPU 101 controls the operation of the overall feature scene detecting apparatus 100. The memory 102 is a memory device for loading various programs to control the operation of the overall feature scene detecting apparatus 100. The auxiliary memory device 103 is a memory device for storing the various programs and data. The display device 104 can be a Cathode Ray Tube (CRT), for example, which displays the result of output from the feature scene detecting apparatus 100. The keyboard 105 and the mouse 106 are input devices which input requests to the feature scene detecting apparatus 100. The video input device 107 can be a capture board, for example, which converts a video signal outputted from the video replay device 109 into a digital still image for input. Further, the video input device 107 obtains a time code corresponding to the digital still image. The interface 108 controls the operation of the video replay device 109 from the feature scene detecting apparatus 100 and sends a command from the video replay device 109 to the feature scene detecting apparatus 100. The video replay device 109 replays a video image stored in a video tape or the like. The feature scene detecting apparatus 100 comprises a feature scene detection processor 110, a feature scene classification processor 111, a video acquisition processor 112 and a feature scene replay processor 113. The feature scene detection processor 110 detects feature scenes included in a video image. The video image can be divided and recorded in a plurality of sequential streams. Further, the video image can comprise time information, such as time codes, indicative of replay time of the feature scenes. The feature scene classification processor 111 obtains a detection frequency of the feature scenes per unit period based upon the time information of the detected feature scene. In a specific embodiment, the feature scenes are stored consecutively in the plurality of sequential streams. The feature scene classification processor classifies and records a specific group of feature scenes having a detection frequency equal to or greater than a threshold value. The video acquisition processor 112 obtains a specific group of feature scenes having a detection frequency per unit period equal to or greater than a threshold value from among feature scenes included in a video image, from recording media. The feature scene replay processor 113 replays the obtained specific group of feature scenes by a replay method different from a normal replay method. The replay method may be slower, or less bright, for example, in order to minimize health effects on the viewer. A program for causing the feature scene detecting apparatus 100 to function as the feature scene detection processor 110, the feature scene classification processor 111, the video acquisition processor 112 and the feature scene replay processor 113 is recorded on a recording medium, such as a CD-ROM, and stored into a magnetic disk or the like, then loaded into a memory of a computer to be executed by the processor. Note that the recording medium in which the program is recorded may be a recording medium other than the CD-ROM. A video image replayed by the video replay device 109 includes a plurality of still images, and a time code stored in each still image. Further, a request to the feature scene detecting apparatus 100 may be sent from the video replay device 109 via the interface 108. The video input device 107, such as a capture board, inputs a video signal outputted from the video replay device 109, then sequentially converts respective frames of the video image into digital still images and sends the images to the respective processors of the feature scene detecting apparatus 100. Further, the video input device 107 obtains time codes corresponding to the digital still images from the video signal. In the feature scene detecting apparatus 100, the digital still images and time codes enter the memory 102 via the video input device 107, and are processed by the CPU 101 in accordance with the program loaded in the memory 102. The digital still images, the time codes, and the various information resulting from processing by the CPU 101 can be stored in the auxiliary memory device 103, in accordance with the processing by the CPU 101. Next, the processing by the CPU 101 of the image information will be described. Fig. 2 is a flowchart showing a processing procedure of feature scene detection processing in a representative embodiment according to the present invention. This processing is executed when the user requests start of detection processing using the mouse 106 or the keyboard 105, or when the start of the detection processing is requested from the video replay device 109. When the processing is executed, the feature scene detection processor 110 sets a number RollCnt uniquely indicating a detection object to be detected from a plurality of video images (step 201). The number RollCnt may be set by numbering in video-image input order, for example. Next, from the video image as a detection object, a digital still image, fi, and a time code, TCi, are captured via the video input device 107 (step 202). The time code TCi is stored as a head time code of the video image (TCrs) (step 203). Next, a feature amount of the digital still image fi is calculated (step 204). Then, it is determined based on the feature amount whether the image fi is a feature scene (step 205). If it is determined that the image fi is a feature scene, then the digital still image fi, the feature amount computed in step 204 and the time code TCi are added to a list (step 206). The list can manage feature scenes in detected order, for example. Further, the digital still image fi is displayed in a table on the display device 104 in Fig. 1 (step 207). Next, at step 208, it is determined whether the next digital still image fi+1 is to be processed. At this time, if the user requests to terminate the detection processing by the mouse 106 or the keyboard 105 or if detection processing termination is requested from the video replay device 109 in Fig. 1, the detection processing ends, and then processing at step 211 is performed. Otherwise, if detection processing termination is not requested, the next digital still image is read (steps 209 and 210), and processing from step 204 is continued. If the detection processing is halted at step 208, then the time code TCi immediately before the cessation of detection processing is stored as a time code (TCre) indicating the end of the video image (step 211). The remainder of steps in the flowchart illustrated by Fig. 2 will be discussed with reference to a data structure illustrated in Fig. 3. Fig. 3 shows a structure for data about detected feature scenes in a representative embodiment according to the present invention. Fig. 3 illustrates an element 301, comprising a video image number 302, a start time code 303 and an end code 304 of a video image, and the feature scene list 305 generated at step 206, in correspondence with each other, are elements of a ROLL list (step 212). A representative ROLL list that manages the data representing detected feature scenes is shown in Fig. 3. Elements 301 indicating respective video images are managed in a linear list with head data 307 indicating the head of the list. The head data 307 has a pointer to a head element 301 and the number of elements. The element 301 has the video number 302, the start time code 303 and the end time code 304 of the video image, the feature scene list 305, and a pointer 306 to the next element in the list. At step 213 of Fig. 2, the feature scene classification processor 111 arranges feature scenes 308 from the head scene, in each element of the ROLL list. Based upon the time codes of the feature scenes 308 being consecutive in a plurality of sequential streams, feature scene classification processor 111 calculates the number of feature scenes 308 detected per second, for example. The processor selects a portion of feature scenes having the number feature scenes detected equal to or greater than a preset threshold value, and classifies it as a group (step 213). The results of classification step 213 will be discussed with reference to Fig. 4. Fig. 4 shows a data structure after the completion of the detection processing in a representative embodiment according to the present invention. The results of classification of the feature scenes into groups managed in a list is shown in Fig. 4. Fig. 4 illustrates a group list 401 managing elements 402, each indicating a group. Elements 402 indicate a group list 403, comprised of elements 404, each indicating a feature scene belonging to the group. The number of the element 404 indicating the feature scene in this figure corresponds to the number of the feature scene 308 in Fig. 3. The term "detection result" will be used to indicate the data generated at step 213. Then, at step 214, the feature scene detection processor 110 displays the detection result generated at step 213. If the user requests feature scene detection processing in another sequential stream at step 215, the process returns to step 201, and further feature scene detection processing is performed. Further, when the user requests termination of the feature scene detection, the feature scene detection processing ends. In an alternative embodiment, steps 213 and 214 may be executed after step 215, enabling a plurality of feature scenes to be processed prior to creating the data structures of Fig. 3 and Fig. 4. Fig. 5 shows an example user interface for the feature scene detecting apparatus 100 in a representative embodiment according to the present invention. The user uses the mouse 106 or the keyboard 105 in Fig. 1, to operate a mouse pointer 501 to point to a desired position on the user interface. A video display area 502 displays an object video image and a time code added to the image. A video image that is the object of detection and a video image that is the object of detection-result checking are displayed in this area. A detection operation start button 503 is used to request start of a detection operation. The feature scene detection processing in Fig. 2 is started by clicking this button using the mouse pointer 501. Further, a detection operation end button 504 is used to request termination of the detection operation. The feature scene detection processing in Fig. 2 is terminated by clicking this button using the mouse pointer 501. A feature scene table area 505 is used to display a table of detected feature scenes. The results of the feature scene detection processing in Fig. 2 are displayed in this area. The correspondence between the video images and the results of detection is as shown in Fig 6. Fig. 6 shows the correspondence between the video images and the results of feature scene detection processing in a representative embodiment according to the present invention. In Fig. 6, still images 601 and 602 are detected based on luminance change. A scroll bar 506 is used when all of the results of detection cannot be displayed in the feature scene table area 505. As the buttons and scroll bar used in the user interface are often used in general personal computer processing, the detailed description on these tools is well known to those of ordinary skill in the art. A group icon 507 of Fig. 5 indicates a group detected by the feature scene detection processing in Fig. 2. The group is selected by selection of this icon using the mouse pointer 501, for example. The still images, the time codes and the feature amounts of the images, detected by the feature scene detection processing in Fig. 2, are displayed in icons 508 belonging to the group. Fig. 7 shows a display of a total period of all the video images in the feature scene detecting apparatus 100 of a specific embodiment according to the present invention. Fig. 8 shows a display of roll number and time code within the roll, in the feature scene detecting apparatus 100 of a specific embodiment according to the present invention. The time code is displayed below the group icon 507 and the icon 508, which belong to the group, as well. The display is of the total time period for the entire video image, and is continuous in a plurality of sequential streams as shown in Fig. 7. The display includes a combination of a title of the video image and its time code as shown in Fig. 8. A detection order display area 515 of Fig. 5 is used to display the detection order of a plurality of video images. A video length 510 indicates the length of each video image, and a video title 516 indicates the title of the video image. To delete all the results of detection, deletion processing is performed by clicking an initialize button 509. Further, if a junction between respective video images is designated by a pointer 511, the result of detection from a new video image is inserted at an arbitrary position among the results of detection for a plurality of existing video images. The position to insert the result of detection may be automatically designated if unique time codes are written in all the video images as detection objects. A video replay button 514 is used for performing a checking operation on the detection result video images. When a group is selected and this button is depressed, video image replay is performed beginning at an image corresponding to a time code indicating the group start time to a time code indicating the group end time. Video replay method buttons 512 and 513 indicate video replay methods for display in the video display area 502. The video replay method button 513 is used to change red coloration. If this button is depressed, processing to display a video image with changed red coloration in the video display area 502 is performed. The video replay method button 512 is used to perform slow replay. If this button is depressed, processing to slowly display a video image in the video display area 502 is performed. Fig. 9 is a flowchart showing a processing procedure of video replay processing in a representative embodiment according to the present invention. The flowchart of the video replay processing in Fig. 9 will be described for a case in which the results of feature scene detection processing of Fig. 2 are generated prior to the start of video replay processing. This processing is performed when the group icon 507 is selected and the video replay button 514 is depressed. When the processing of Fig. 9 is performed, the video acquisition processor 112 obtains a group head video image number RollCnts and a time code TCs (step 901). Video acquisition processor 112 also obtains a group end video image number RollCnte and a time code TCe (step 902). Then, the processor stores the number RollCnts as the current video image number RollCnti (step 903). Next, the process waits until the RollCnts-th video image is set in the video replay device 109 (step 904). Then, video fast forward or rewind is performed to a position corresponding to the time code TCs in the video replay device 109 (step 905). Next, replay is started from the position set at step 905. In a step 906, a still image fi and its time code TCi are sequentially obtained. Then at step 911, the still image fi is displayed. Finally, at steps 912, 913 and 917, it is determined whether the video replay is to be continued. First, at step 912, it is determined whether the current video image number RollCnti is less than the group end video image number RollCnte. If the current video image number is less than the group end video image number, it is determined at step 913 whether the entire video image of the video image number has been replayed. If the entire video image of the current video image number has not been replayed, then the processing from step 906 is continued. On the other hand, if the entire video image of the current video image number has been replayed, a video image of the next video image number is set in steps 914 to 916 before the processing at step 906 is continued, and a time code TCrs in the start position of the video image of the next video image number is set in the video replay device 109 (steps 914 to 916). If it is determined at step 912 that the current video image number is equal to the group end video image number, it is determined whether the time code TCi of the current video image is greater than the group end time code TCe. If the current video time code TCi is equal to or less than the group end time code TCe, the processing from step 906 is continued. Further, if the current video time code TCi is greater than the group end time code TCe, the video replay is stopped, and the process ends. The video replay is performed by the above processing. Next, a processing method to replay and check a video image in a specific embodiment according to the invention will be described. This processing is realized by adding processing for steps 907 to 910 between steps 906 and 911. First, a representative example method of changing red coloration in a specific embodiment according to the present invention will be described. This processing is performed when the video replay method button 513 in Fig. 5 is selected. In the flowchart of Fig. 9, at step 907, the feature scene replay processor 113 determines whether the video replay method button 513 is selected, and if it has been selected, the red coloration change processing is performed (step 908). Fig. 10 shows an overview of color information change in a representative embodiment according to the present invention. A technique for changing red coloration in a HIS (Hue, Intensity and Saturation) color model is shown in Fig. 10. In the example of Fig. 10, a part 1001 indicates the range of red to be changed, a color 1002 belonging to the part 1001 is replaced with a color 1003 out of the range of red, nearest to the value of the color 1002, based on the boundary between the part 1001 and the space other that the part 1001 as a threshold value. Next, processing for replaying a video image at a low speed in a specific embodiment according to the invention will be described. This processing is performed when the video replay method button 512 in Fig. 5 is selected. In the flowchart of Fig. 9, at step 909, the feature scene replay processor 113 determines whether the video replay method button 512 is selected, and if it has been selected, the processing for low-speed video image replay is performed (step 910). Fig. 11 shows an overview of a feature scene slow replay technique in a representative embodiment according to the present invention. A technique for performing low-speed video replay will be discussed with respect to an example case of replaying a video image part 1102 of video image 1101 in Fig. 11. In this example, replay is performed with replay stoppage for n seconds between respective still images of the video image part 1102. The replay stoppage period of n seconds can be obtained from the following expression, for example, with a threshold value for an average number of detections per second, used in group classification: n = 1/30 × (Maximum number of detections per second - average number of detections as threshold value upon group detection + 1) The above expression is an example of one technique for obtaining n. In case of simple low-speed replay, replay independent of content can be made by performing the replay with the value n as a fixed value equal to or greater than 1. As described above, as the feature scene detecting apparatus of a specific embodiment according to the present invention performs feature scene detection for video images, including video images that have been divided and recorded in a plurality of sequential streams as a continuous video image. Thus, embodiments according to the present invention can perform feature scene detection over a boundary between two sequential streams. Further, in a feature scene detecting apparatus of a specific embodiment according to the present invention, a specific group of feature scenes can be replayed using a replay method different from a normal replay method, so that when the feature scene is checked, an operator will not suffer adverse effects from replaying the feature scene. Specific embodiments include any of replaying the feature scene at slower than normal speed, replacing red color with other colors, and the like. According to the present invention, as feature scene detection is performed while a video image that has been divided and recorded in a plurality of sequential streams is handled as a continuous video image, feature scene detection over a plurality of sequential streams can be performed. The preceding has been a description of the preferred embodiment of the invention. It will be appreciated that deviations and modifications can be made without departing from the scope of the invention, which is defined by the appended claims.

Claims: A feature scene detecting apparatus (100) for detecting a specific feature scene included in a video image, comprising: a feature scene detection processor (110) that detects feature scenes included in a video image, divided and recorded in a plurality of sequential streams so as to divide at least one feature scene between any two of said plurality of sequential streams, with time information indicative of replay time of the feature scenes; and a feature scene classification processor (111) that obtains a detection frequency of the feature scenes per unit period, based upon said time information of the detected feature scenes in the plurality of sequential streams, and classifies and records a specific group of feature scenes which is a selected portion of the detected feature scenes having a detection frequency, that is the number of the detected feature scenes in the portion per unit time, equal to or greater than a threshold value. The feature scene detecting apparatus for detecting a specific feature scene included in a video image of claim 1, said apparatus further comprising: a video acquisition processor (112) that obtains a specific group of feature scenes having a detection frequency per unit period equal to or greater than a threshold value, among feature scenes included in a video image, from a sequential stream; and a feature scene replay processor (113) that replays said obtained specific group of feature scenes using a replay technique to reduce a health risk to a viewer. The feature scene detecting apparatus (100) for detecting a specific feature scene included in a video image of claim 2, wherein said replay technique to reduce a health risk to a viewer further comprises any selected from a technique of replaying the feature scenes at a slower than normal rate, a technique of replaying the feature scenes using a color substituted for a colour used in the scene. A method for detecting a specific feature scene in a video image, said video image divided and recorded into a plurality of sequential streams so as to divide at least one feature scene between any two of said plurality of sequential streams, said video image having time information indicative of replay time of said feature scenes, said method comprising: searching at least one of a plurality of frames comprising said video image for feature scenes, and if a feature scene is located, storing information about said feature scene into a first list; computing a detection frequency of said feature scenes per unit time period; classifying a specific group of feature scenes which is a selected portion of the detected feature scenes having a detection frequency, that is the number of the detected feature scenes in the portion per unit time, equal to or greater than a threshold value. The method for detecting a specific feature scene in a video image of claim 4, wherein said plurality of sequential streams includes at least a first sequential stream and a second sequential stream, said video image including at least one feature scene having a first portion recorded in said first sequential stream and a second portion recorded in said second sequential stream, said searching at least one of a plurality of frames further comprising determining based upon said time information that said first portion and said second portion comprise said at least one feature scene. The method for detecting a specific feature scene in a video image of claim 4, wherein said searching said video image for feature scenes further comprises: capturing a frame image and a corresponding time code; computing a feature amount for said frame image; determining based upon said feature amount whether said frame image is a feature scene, and if said frame is determined to be a feature scene, storing information about said feature scene into a first list; and repeating said capturing, computing and determining for subsequent frame images. The method for detecting a specific feature scene in a video image of claim 4, wherein said computing a detection frequency of said feature scenes per unit time period further comprises: determining a number of feature scenes detected, based upon said information about said feature scene stored into said first list; determining a time period from said time information corresponding to said detected feature scenes in the plurality of sequential streams; and computing said detection frequency of the feature scenes per unit time period from said number of feature scenes detected and said time period. The method for detecting a specific feature scene in a video image of claim 4, wherein said classifying further comprises: selecting from said feature scenes groups of feature scenes having a number of feature scenes detected per unit time period equal to or greater than said threshold value; and storing said groups of features scenes into a second list. The method for detecting a specific feature scene in a video image of claim 4, said method further comprising: obtaining a specific group of feature scenes having a detection frequency per unit period equal to or greater than a threshold value, among feature scenes included in a video image; replaying said obtained specific group of feature scenes using a replay technique to reduce a health risk to a viewer. The method for detecting a specific feature scene in a video image of claim 9, wherein said replay technique to reduce a health risk to a viewer further comprises any selected from a technique of replaying the feature scenes at a slower than normal rate, a technique of replaying the feature scenes using a color substiruted for a colour used in the scene. A computer program product for detecting a specific feature scene in a video image, said video image divided and recorded into a plurality of sequential streams so as to divide at least one feature scene between any two of said plurality of sequential streams, said video image having time information indicative of replay time of said feature scenes, said computer program product comprising: code that searches at least one of a plurality of frames comprising said video image for feature scenes, and if a feature scene is located, stores information about said feature scene into a first list; code that computes a detection frequency of said feature scenes per unit time period; code that classifies a specific group of feature scenes which is a selected portion of the detected feature scenes having a detection frequency, that is the number of the detected feature scenes in the portion per unit time, equal to or greater than a threshold value; and a computer readable storage medium for holding the code. The computer program product for detecting a specific feature scene in a video image of claim 11, wherein said plurality of sequential streams includes at least a first sequential stream and a second sequential stream, said video image including at least one feature scene having a first portion recorded in said first sequential stream and a second portion recorded in said second sequential stream, wherein said code that searches at least one of a plurality of frames determines based upon said time information that said first portion and said second portion comprise said at least one feature scene. The computer program product for detecting a specific feature scene in a video image of claim 11, wherein said code that searches said video image for feature scenes further comprises: code that captures a frame image and a corresponding time code; code that computes a feature amount for said frame image; code that determines based upon said feature amount whether said frame image is a feature scene, and if said frame is determined to be a feature scene, stores information about said feature scene into a first list; and code that repeatedly invokes said code that captures, code that computes and code that determines for subsequent frame images. The computer program product for detecting a specific feature scene in a video image of claim 11, wherein said code that computes a detection frequency of said feature scenes per unit time period further comprises: code that determines a number of feature scenes detected, based upon said information about said feature scene stored into said first list; code that determines a time period from said time information corresponding to said detected feature scenes in the plurality of sequential streams; and code that computes said detection frequency of the feature scenes per unit time period from said number of feature scenes detected and said time period. The computer program product for detecting a specific feature scene in a video image of claim 11, wherein said code that classifies further comprises: code that selects from said feature scenes groups of feature scenes having a number of feature scenes detected per unit time period equal to or greater than said threshold value; and code that stores said groups of features scenes into a second list. The computer program product for detecting a specific feature scene in a video image of claim 11, said computer program product further comprising: code that obtains a specific group of feature scenes having a detection frequency per unit period equal to or greater than a threshold value, among feature scenes included in a video image; and code that replays said obtained specific group of feature scenes using a replay technique to reduce a health risk to a viewer. The computer program product for detecting a specific feature scene in a video image of claim 16, wherein said replay technique to reduce a health risk to a viewer further comprises any selected from a technique of replaying the feature scenes at a slower than normal rate, a technique of replaying the feature scenes using a color substituted for a colour used in the scene. The apparatus of claim 1 wherein the apparatus includes means for searching at least one of a plurality of frames comprising said video image for feature scenes, and if a feature scene is located, storing information about said feature scene into a first list. The apparatus for detecting a specific feature scene in a video image of claim 18, said apparatus further comprising: means for obtaining a specific group of feature scenes having a detection frequency per unit period equal to or greater than a threshold value, among feature scenes included in a video image; and means for replaying said obtained specific group of feature scenes using a replay technique to reduce a health risk to a viewer.

Inventors: AMEMIYA HIROKAZU, HAGIHARA YOSHINOBU, OMATA MITSUTERU, SAGA TOSHIHIDE, SAKAMOTO KATSUTO, YAMAMITSU TADASHI, AMEMIYA, HIROKAZU, HAGIHARA, YOSHINOBU, OMATA, MITSUTERU, SAGA, TOSHIHIDE, SAKAMOTO, KATSUTO, YAMAMITSU, TADASHI, Amemiya, Hirokazu c/o Hitachi Ltd., Intel.Prop.Gr., Hagihara, Yoshinobu c/o Hitachi Ltd.,Int.Prop.Gr., Omata, Mitsuteru c/o Hitachi, Ltd., Intel.Prop.Gr., Saga, Toshihide c/o Akita Electronics Co. Ltd., Sakamoto, Katsuto c/o Hitachi Ltd.,Int.Prop.Group, Yamamitsu, Tadashi c/o Hitachi Ltd.,Intel.Prop.Gr.
Applicants: HITACHI LTD, HITACHI, LTD.
Application year: 2000
Main classification: H04N5
IPC codes: G11B27, G06F17