Data processing: database and file management or data structures – Database design – Data structure types
Reexamination Certificate
2000-01-28
2004-05-25
Alam, Shahid (Department: 2172)
Data processing: database and file management or data structures
Database design
Data structure types
C707S793000, C707S793000, C348S135000, C348S143000, C348S155000
Reexamination Certificate
active
06741977
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to an image recording/playback apparatus which is designed for use in a system for monitoring various events taking place in a place concerned by making use of movie techniques. More particularly, the present invention is concerned with an improvement of the image recording/playback apparatus which makes it possible to survey and/or retrieve a monitoring picture or image recorded over an extended period within a short time on the order of one several-tenth of the recording period. Further, the present invention is concerned with a image recording/playback method and a recording medium which stores the method in the form of a program executable with a computer.
In a place such as supermarket, convenience store, elevator hall or the like which is frequented by a large number of persons and which is difficult to be surveyed by a person in charge of management or watching, a monitoring camera is installed for the purpose of preventing accidents and/or crimes in advance. In this conjunction, the monitoring system for monitoring the places such as mentioned above by viewing the moving images or pictures taken by such monitoring camera can generally be classified into two types, i.e., a system which necessitates a constant survey of collected images picked up by the monitoring cameras by a person at a center station (hereinafter referred to as the online-type monitoring system) and a system in which pictures or images taken by the monitoring camera are stored accumulatively for allowing survey and inspection thereof later as occasion requires, e.g. upon commitment of offense or crime (hereinafter this type of monitoring system will be referred to as a storage-type monitoring system). The storage-type monitoring system involves scarcely personnel expenses when compared with the online-type monitoring system. For this reason, the former is adopted widely in practical applications. At this juncture, it is noted that in the storage-type monitoring system, a time-lapse video recorder is primarily employed for storing and playback the pictures or images as picked up by the monitoring camera.
With the time-lapse video recorder, such a video recorder is meant which is modified on the basis of a conventional video recorder such that the time interval for recording the images at a rate of thirty frames per second is increased to an interval on the order of several frames per second for recording only sparsely. Thus, with the time-lapse video recorder based on the conventional video recorder, it is possible to perform the recording over a period of about 180 hours (about eight days) by recording at the rate of one frame per second by using a tape medium capable of recording over 120 minutes with the conventional video recorder. Of course, by increasing the frame interval, recording can be performed over a further extended period which will however be accompanied with dropout of image of some object under monitoring, to a disadvantage. For this reason, the recording interval which exceeds one second or so is not adopted in practical applications. Further, it is conceivable to use a tape medium which can ensure a recording duration which exceeds 120 minutes or so. However, in consideration of durability (or possibility of breakage) of the tape medium, the tape which allows recording over 120 minutes or so is usually employed. Such being the circumstances, the longest recording time duration of the time-lapse video recorder based on the conventional video recorder is approximately 180 hours.
Image recording is performed starting from the leading end of the tape toward the trailing end thereof. Upon reaching the trailing end of the tape in the image recording operation, tape rewinding operation is automatically put into effect, whereon overwriting operation is performed, starting again from the leading end of the tape. In this manner, a series of images can be stored ordinarily over a time span of 180 hours or so at maximum. For perusing or surveying the images as recorded, substantially same method as that for the conventional video recorder can be resorted to. However, when the images recorded by the time-lapse video recorder based on the video recorder are to be reproduced straightforwardly in a same manner as the picture recorded by the conventional video recorder, the playback speed may amount to be thirtyfold.
Accordingly, the time-lapse video recorder is ordinarily provided with a mechanism for allowing the recorded images to be reproduced at a rate of several frames per second.
Among the time-lapse video recorders, there has been developed such a recorder in which a digital recording on a hard disk is adopted. With the time-lapse video recorder which is based on the VHS video recorder, the recording head may be damaged because recording/stop operations are mechanically repeated. Besides, the tape medium is likely to become degraded, incurring deterioration of quality of the reproduced images. These problems can certainly be solved by the digital recorder mentioned above. Parenthetically, the digital recorder is generally termed the digital time-lapse video recorder distinctively from the time-lapse video recorder based on the conventional VHS video recorder.
As will now be appreciated from the foregoing, monitoring images can be stored over an extended time period with the time-lapse video recorder. However, the time-lapse video recorder suffers serious problems with regard to the image reproduction for the survey or perusal. Firstly, it has to be pointed out that several times as long as the recording time of the recording medium (120 minutes in the case of the video tape) will be taken for observing thoroughly all the images or pictures recorded during the extended period of for 180 hours. Secondly, effectiveness of search and/or perusing (or surveying) operations is extremely poor because of disordered states of the objects concerned with images of significance and insignificance being recorded concurrently and alternately. In the present state of the art, reproduction is performed simply from the leading end of the tape while observing the images only rumblingly, which will often result in failure to notice the image of interest or concern, to a great disadvantage.
As is apparent from the above, the perusal of the images recorded accumulatively with the time-lapse video recorder imposes a great burden on the user because of necessity for concentrative observation of the images over a much extended time period.
At this juncture, it should be added that as an approach for solving the problems mentioned above, there has already been proposed such a monitoring system in which an infrared sensor such as a man-sensor is combined with the time-lapse video recorder. However, such system suffers many drawbacks. Firstly, with the time-lapse video recorder based on the VHS video recorder, mechanical portion for effectuating the recording/stop operations will be damaged at a relatively high failure rate because of frequent on/off operations. Secondly, reliability can not be ensured in respect to the effective coverage range of the sensor and the sensitivity thereof. Thirdly, high cost will be involved in retrofitting the monitoring system. For these reasons, combination of the sensor with the time-lapse video recorder is seldom adopted in the practical applications, leaving the aforementioned problems unsolved.
SUMMARY OF THE INVENTION
The fundamental problem of the conventional time elapse video recorder can be found in that the image data as inputted to the recorder are simply recorded on a time serial basis without performing any classification of the data. In this conjunction, let's suppose a case where a person monitors a certain place as to occurrence of some event. In that case, he or she will take notes of the events such as, for example, coming-in/out of persons, positional changes of equipment or the like for classification and orderly arrangement with a view to facilitating the search or retrieval of the events as
Fujita Takehiro
Miyatake Takafumi
Nagasaka Akio
Nagaya Shigeki
Alam Shahid
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Woo Isaac
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