JP2000125256A - Video recording device and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a digital time lapse video recorder which is excellent in retrieval performance, has less image deterioration and performs video recording for a long time at low cost by compressing an image decided as a subject to video recording, adding input time information to it, recording it and displaying an image in the middle of being currently inputted or a stored image. SOLUTION: An image decided as a subject to video recording by a filtering means is compressed, input time information is attached to it, it is subjected to video recording, and an image in the middle of being currently inputted or a stored image is shown. In this device, an image is fetched in every fixed time interval, and only needed images are selected through image filtering and are subjected to video recording after data compression is performed. The fetched images are sequentially transferred to a video memory 118 while first storing the fetched images in a memory 170 according to a control program stored in the memory 170 and an input image 210 is shown on a display. Further, a selected image is stored as video recorded data in an auxiliary storage device 160 after filtering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video recording apparatus used in the field of video monitoring and a computer-readable recording medium on which a control program for the video recording apparatus is recorded. In particular, the present invention relates to a digital time-lapse video recorder capable of recording digital video for a long time at low cost, and a recording medium on which a control program of the digital time-lapse video recorder is recorded.

[0002]

2. Description of the Related Art At present, surveillance using camera images is performed at various places such as roads, railroad crossings, service floors of banks, convenience stores, and condominiums. The purpose of such monitoring is to provide a system that can prevent accidents and crimes before they occur and take immediate action after the fact.

In a department store or a convenience store, a monitoring system for preventing accidents and crimes beforehand requires technology for automatically detecting abnormalities of customers exhibiting suspicious behavior. In this situation, the observers have to check the images on the TV monitor. Therefore, there is a problem that the cost of a monitoring system for preventing accidents and crimes is high.

On the other hand, a surveillance system for post-processing can be expected to have the effect of suppressing crime. At present, in condominiums and convenience stores, surveillance systems that constantly record camera images using a time-lapse video recorder are widely used. The time-lapse video recorder has a feature that it can be recorded on a single video tape for several days. The reason that long-time recording is possible is that while a normal video recorder records 30 frames per second, a time-lapse video recorder sets the recording time interval freely. This is because For example, if the recording time interval is set to one frame per second, a 60-hour image can be recorded on a video tape capable of recording for two hours. Then, if the recording is continued endlessly using this device, the image up to three days before is always recorded on the video tape. Therefore, in the example of this monitoring system, it is possible to investigate the situation retroactively up to three days before the discovery of the incident.

[0005] However, it is not easy to examine the contents of a video tape recorded by a time-lapse video recorder. When a video is viewed at a normal playback speed, a videotape recorded at one-second intervals looks like a 30-times moving image, making it difficult to grasp the contents. Therefore, in order to check the contents of the image, it is necessary to perform the operation of sending each frame.
There is a problem that a great deal of labor is required. In addition, since the tape is usually overwritten and used many times, the deterioration of the image quality becomes a problem. In some cases, such as "the criminal's face is not clearly seen" occurs, and the purpose of monitoring cannot be achieved.

[0006]

As described above, the conventional time-lapse video recorder is excellent in that it can record for a long time at a low cost. There was a problem. That is, there are problems that a videotape recorded for a long time must be viewed by frame-forwarding operation, and a searched image is not always clear.

An object of the present invention is to provide a digital time lapse video recorder which has excellent search performance, has little image quality deterioration, and can record at low cost for a long time.

[0008]

In order to solve the above-mentioned problems, a sampling time setting means for setting a recording time interval, a means for inputting and digitizing an image in a time series, and a method for inputting an image at a sampling time. Filtering means for determining whether or not to record based on a predetermined criterion, image compression means for compressing an image determined to be "recorded" by the filtering means, and recording of the compressed image with input time information added thereto An image recording means and an image display means for displaying one or a plurality of images currently input or stored in the image recording means are provided.

The filtering means calculates the degree of difference between the input image at the sampling time and the image recorded in the past, and when the degree of difference exceeds a predetermined value, determines "record". Note that the previously recorded image is used as the previously recorded image. Also, as the degree of difference, an average value of color or luminance is calculated for each block from the image, the absolute value of the difference between corresponding blocks of the two images is obtained, and the maximum value thereof is used.

[0010] The medium of the image recording means uses a random access memory such as a hard disk, a DVD-RAM, and a flash memory.

Still another solution means is a sampling time setting means for setting a recording time interval, a means for inputting images in time series, and whether or not to record an input image at a sampling time according to a predetermined standard. "Record" by filtering means and filtering means
Image recording means for adding the input time information to the image determined to be recorded, and image display means for displaying one or more of the image currently being input or the image stored in the image recording means.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail.

FIG. 1 shows an example of a surveillance system using a digital time lapse video recorder according to the present invention.
A video signal from the surveillance camera 200 is input from a video input terminal 110 of the digital time lapse video recorder 100 and recorded as a digital image. The recorded digital image is displayed on the display 220 as an analog image from the video output terminal 110. The recorded digital image is sent from the modem terminal 140 to the monitoring center through a telephone line. At that time, mobile phone 2
10 and the like are also available. The digital time-lapse video recorder 100 is controlled by an instruction from a remote controller via the infrared light receiving unit 130.

As described above, a conventional analog surveillance camera or display can be directly connected to the monitoring device connected to the digital time lapse video recorder 100 of the present invention. Further, the fact that an image can be transmitted to a distant place via a modem is a function not provided in the conventional time-lapse video recorder.

FIG. 2 is an embodiment of a system configuration diagram of a digital time lapse video recorder according to the present invention. Basically, the system configuration is the same as that of a digital computer that is currently widely used.

First, reference numeral 111 denotes a video signal 2 from the surveillance camera.
An A / D converter for converting 10 into a digital image. The converted digital image is taken into the memory 170 via the interface 112 and simultaneously with the video memory 118.
It is taken in. The video memory 118 is a display 2
The image displayed at 20 is stored as digital data. 119 is a kind of D / D that is also commonly called RAMDAC.
The A converter reads data written in the video memory 118 sequentially according to the scanning line speed and draws the data on the display 220. Therefore, the video memory 118
Is updated, the updated content is displayed on display 2.
This is immediately reflected on the display content of No. 20. Display 22
0 is a device for displaying an image, for example,
It may be a small CRT or plasma display,
It may be a liquid crystal display device. By repeating such image capturing at a frequency of about 30 times per second, a continuous moving image can be displayed on the display.
The auxiliary storage device 160 is a large-capacity recording device such as a hard disk, and is a device for semi-permanently recording digital data. This may be a recording device such as a PCMCIA hard disk card that can be attached to and detached from the main body of the storage device, or a recording device such as a DVD-RAM and a flash memory that can be attached and detached only from a recording medium. CPU 150 executes software programs for realizing the functions described in the present invention, including control for recording. The program resides in the memory 170, and data necessary for executing the program is also stored here as needed. The modem 139 transmits the recorded image and additional information through a telephone line. Infrared receiver 13
0 is an information input device from a remote controller. The input information is transmitted to the CPU 150 via the interface 131, and is appropriately processed. Reference numeral 180 denotes a data bus for interconnecting the devices described above.

In the system configuration of the digital time-lapse video recorder described above, in the present embodiment, images are captured at regular time intervals, only necessary images are selected by filtering the images, data is compressed, and then recorded. First, according to the control program stored in the memory 170, the captured image is sequentially transferred to the video memory 118 while being stored in the memory 170, and is displayed on the display 2.
The input image 210 is displayed on 20. After the filtering, the selected image is stored in the auxiliary storage device 160 as recording data.

FIG. 3 is a diagram showing the principle of realizing low-cost long-time recording according to the present invention. Reference numeral 300 is a timing chart showing a generation cycle of the video signal. 1 in the NTSC standard
30 frames are generated per second. On the other hand, frames are thinned out temporally by taking in images at specified sampling intervals. Reference numeral 310 shows a timing chart of sampling. In this example, the frames are thinned to 1/30, and only one frame is taken in one second.
The timing of this sampling can be freely set. However, if the sampling interval is too wide for long-time recording, if the intruding object in the monitoring area passes quickly, recording omission occurs, and the purpose of monitoring cannot be achieved. Therefore, the present invention provides a method capable of recording for a long time without increasing the sampling interval. Reference numeral 320 represents the image content at the sampling timing. When the surveillance camera is fixed and there is no intruding object or change in the background, the input image sequences are almost similar. Therefore, in the present invention, when it is determined that the previously recorded image is the same as the image to be currently recorded, the recording is omitted to save memory consumption for the recording. 330 indicates the filtered and selected frame. When such filtering is performed, a fixed time is consumed in a time zone where the image changes a lot, but when the change is small such as at night, the memory consumption is reduced,
Long-time recording becomes possible. The image at the time when recording was omitted is the same as the image recorded immediately before it, so even if there is an image search request at the time when recording was omitted, the result can be displayed as a substitute image It is. Recording data 1
Since 61 is composed of a still image and the time at which it was acquired, in the example of FIG. 3, “display the image at time 1”.
, The image at time 0 may be displayed as a proxy.

As described above, according to the present invention, since the image content is determined and the recording is omitted, the recording time can be lengthened without causing a recording omission of an intruder. effective.

FIG. 4 shows an embodiment of a remote controller for giving an instruction to the digital time lapse video recorder of the present invention. All instruction commands from the remote controller 400 are issued via infrared signals from the infrared light emitting unit 420.
A button 410 is used to instruct power ON / OFF. 430
Is a button for instructing recording, 431 is a button for instructing playback display, 432 is a button for instructing a recording interval, 433
Is a button for setting various parameters, and 434 is a paddle switch for selecting an item, which can be pressed left, right, up and down. Reference numeral 435 denotes a paddle switch for setting a numerical value from 0 to 9, and when it is pressed upward, the value becomes large, and 9 is the upper limit. On the other hand, when the lower side is pressed, the value becomes smaller, and 0 is the lower limit.

Next, the operation of the recording interval button 432, the recording button 430, and the playback button 431 will be described below.

When the recording interval button 432 is pressed, the display 220 displays a sampling time setting screen shown in FIG. In the figure, 500 is a cursor, 510
Is a sampling time input area, and 520 is an estimated recording time display area. Move cursor to paddle switch 434
Is operated to move to a predetermined digit in the sampling time input area 510, and the paddle switch 435 is operated to input a predetermined sampling time.

Next, when the cursor is moved to the setting area 530 and the setting button 433 is pressed, the sampling time is set. When the sampling time is set, the estimated recording time is displayed in an area 520. Finally, when the cursor is moved to the area 540 and the setting button 433 is pressed, the sampling time setting screen ends, and the basic screen of FIG. 6 is displayed.

When the record button 430 is pressed, a basic screen shown in FIG. 6 is displayed on the display 220. In the figure, reference numeral 600 denotes a display area for input images, 610 denotes an area for displaying a list of recorded images, and the recorded images 611 are reduced and displayed side by side. 620, 630, 64
0 indicates recording status information, 620 indicates a sampling time interval during recording, 630 indicates a recording start time, and 6 indicates a recording start time.
Reference numeral 40 denotes a recording meter, which indicates how many hours can be recorded. Then, when the recording button 430 is pressed during recording, the recording processing is stopped.

When the play button 431 is pressed, a play screen shown in FIG. 7 is displayed on the display 220. In the figure, 700 is a moving image display area, 710 is a structure display area,
720 is a list display area. Images recorded so far are displayed in the above three formats. For example, when the cursor 500 is moved over a desired time display in the structure display area and the setting button 433 is pressed, the list display area 720 is displayed.
, An image 721 at the corresponding time is displayed along with the acquisition time 722. Further, a corresponding recorded image is reproduced as a moving image in an area 701 of the moving image display area 700.
The moving image is displayed on the operation areas 702, 703, and 704 with the cursor 50.
By moving 0 and pressing the setting button 433, reverse playback, pause, and playback can be performed. When a desired image is found, the moving image display area 700 is enlarged and displayed by moving the cursor to the area 705 and pressing the setting button 433. Although the number of images that can be displayed in the list display area 720 is limited, all images can be browsed quickly by operating the scroll bar in the area 723.

As described above, in the conventional time-lapse video, only the images can be browsed sequentially, but according to the present invention, the recorded images can be accessed either sequentially or randomly, so that the retrieval performance is improved. effective.

FIG. 8 shows an embodiment of the data structure of the recording data 161 of the present invention. The recorded data includes a header section and an image section. In the header part, the recording start date 161-
1. Recording start time 161-2, sampling time 161-3, number of recordings 161-4 are recorded, and in the image section, the image number 161-5, the image acquisition date 161-6, the image acquisition Time 161-7,
The image data 161-8 is recorded.

FIG. 9 shows an embodiment of the recording control program 172 of the digital time lapse video recorder of the present invention. First, step 900 is an initialization process, in which the basic screen of FIG. 5 is displayed on the display. And step 9
At step 05, a variable STATUS1 for controlling the recording state is reset to 0, and at step 910, a variable STAT for controlling the reproduction state.
Reset US2 to zero.

Then, while the power of the digital time lapse video recorder is turned on (step 920), the following control processing is executed.

First, in step 930, the state of the buttons on the remote controller is checked, and the following judgment processing in step 940 is performed.

If the recording interval recording button 432 is pressed, a sampling time setting process is executed in step 941. This processing is an interactive processing with the user, and after the system displays the sampling time setting screen of FIG. 5 on the display, the user operates the remote controller 400 to input a numerical value. When the processing ends, the display of the display returns to the basic screen of FIG.

Next, the determination processing of step 950 is performed.

If the variable STATUS1 is 0 and the recording button 430
If is pressed, recording initialization processing 951 is executed.
In the recording initialization process, the header information of the recording data is
The recording start date, the recording start time, the sampling time, and the recording number N are written in the auxiliary storage device 160. The number of recordings is initially 0. Then, in step 952, the variable STATUS1
Is set to 1 so that the video is being recorded.

If the variable STATUS1 is 1 and the recording button 430
If is pressed, step 953 is executed and the variable STAT
US1 is reset to 0 to end recording.

Next, in the determination processing of step 960, STATUS
If 1 is 1, a recording process is performed in step 961, and an image is written to the auxiliary storage device 160. Details of this recording process will be described later with reference to FIG.

Next, the judgment processing of step 970 is performed.

If the variable STATUS2 is 0 and the play button 431
If is pressed, the reproduction initialization process 971 is executed.
In the recording initialization process, the reproduction screen of FIG. 7 is displayed on the display. Then, in step 972, the variable SSTATU2 is set to 1
To set it to the playback state.

If the variable STATUS2 is 1 and the play button 431
If is pressed, the reproduction end process 973 is executed. In the reproduction end processing, the display of the display is returned to the basic screen of FIG.

Then, in step 973, the variable STASTU2 is reset to 0, and the reproduction is completed.

Next, in the judgment processing of step 980, STATUS
If 2 is 1, playback processing is performed in step 981, and the image recorded in the auxiliary storage device 160 is displayed at a predetermined position on the display.

The above steps 930 to 981
By repeating the above processing, video recording and playback can be realized.

FIG. 10 shows the details of the recording process 961. First, in step 1000, the time difference between the current time p and the previous sampling time t is calculated. And step 100
In step 5, it is determined whether the difference has exceeded a preset sampling time. If the difference has exceeded, the current time is determined to be the timing of image input, and the following processing is executed.

First, in step 10006, the current time p is stored as a sampling time in a variable t. Then, in step 1010, an image from the monitoring camera 200 is input and stored in the memory 170.

Next, by the processing of steps 1020 to 1022, the degree of difference between the image registered immediately before and the input image is obtained. In the present invention, if the images are the same, recording is omitted, thereby preventing wasteful memory consumption. First, in step 1020, the input image is divided into blocks, and an average value of luminance is calculated for each block. Next, in step 1021, the absolute value of the difference between the average value of the luminance of the image registered immediately before and the average value of the luminance of the input image is calculated for each block. Then, in step 1022, the maximum value of the absolute difference value is calculated in each block. In the present invention, this maximum value is used as the degree of difference between images. Since the average value of the luminance for each block is used, there is an effect of being less affected by noise. Next, in step 1030, it is determined whether or not the maximum value of the absolute difference value is larger than a predetermined threshold Th. If it is larger, it is determined that the image has changed, and the image registration processing of steps 1030 to 1060 is executed.

First, at step 1030, the number of recordings N is updated by one. Then, in step 1040, the input image is
Compression is performed to reduce the data amount to one-half. The compression method uses the JPEG method already standardized by ISO. Next, in step 1050, the compressed image is registered in a predetermined location 161-8 of the recorded data 161. And step 1060
Then, as related information, the current recording number N is set as an image number to a predetermined location 161-5, the current date is set as an image acquisition date to a predetermined location 161-6, and the current time is set as an image acquisition time. Each is registered in a predetermined location 161-7.

In the embodiment, the average value of luminance is used for calculating the degree of difference between images. However, when the input image is a color image, the average value is calculated for each of the R, G, and B color components. The method can also calculate the degree of difference. In the embodiment, the image is compressed before the image is registered. However, if the image is already compressed at the input stage, the process of step 1040 can be omitted.

In this embodiment, the maximum value of the absolute difference value of each block is calculated and compared with the threshold value as the degree of difference. However, the absolute difference value of each block is sequentially determined by a threshold. If the value is larger than the threshold value, it is determined that the image has changed, and the image registration processing of steps 1030 to 1060 may be executed.

Instead of comparing with the image registered immediately before, the absolute value of the difference may be compared between the background screen and the input screen stored in advance.

The recording control program of the digital time lapse recorder may be resident in the memory 170 or may be recorded on a computer-readable recording medium such as a CD-ROM.

FIG. 11 shows another embodiment of the digital time lapse video recorder, which is an invention assuming that the surveillance camera is a digital video camera. In this case, the input image has already been digitized. Therefore, the A / D converter required in the system configuration of FIG. 2 becomes unnecessary and is omitted in FIG. Other configurations are the same.

As described above, the digital time lapse video recorder of the present invention can record recorded data in a memory which can be randomly accessed, and thus has excellent search performance. Also, recording for a long time in digital format increases the memory cost. However, in the present invention, recording of the same image is omitted, and memory consumption is reduced. Further, by using the average value of the luminance in block units to determine the degree of difference between images, the operation can be stably performed even for an image having much noise.

[0052]

According to the present invention, recorded data can be recorded in a memory which can be randomly accessed, so that the retrieval performance is excellent, and since the image is digitized, the image quality deteriorates even if recording is repeated many times. However, since recording of the same image is omitted, memory consumption is reduced, and there is an effect that a digital time-lapse video recorder capable of prolonging recording can be provided.

[Brief description of the drawings]

FIG. 1 is an example of a monitoring system using a digital time-lapse video recorder of the present invention.

FIG. 2 is a system configuration diagram of a digital time-lapse video recorder of the present invention.

FIG. 3 is a diagram showing the principle of low-cost long-time recording according to the present invention.

FIG. 4 is an embodiment of a remote controller according to the present invention.

FIG. 5 is an embodiment of a sampling time setting screen of the present invention.

FIG. 6 is an example of a basic screen according to the present invention.

FIG. 7 is an embodiment of a reproduction screen according to the present invention.

FIG. 8 is an embodiment of a data structure of recorded data according to the present invention.

FIG. 9 is an embodiment of a recording control program of the present invention.

FIG. 10 is a detailed flowchart of a recording process according to the present invention.

FIG. 11 is another system configuration diagram of the digital time lapse video recorder of the present invention.

[Explanation of symbols]

100 Digital time-lapse video recorder, 11
0: video input terminal, 111: A / D converter, 118: video memory, 119: D / A converter, 120: video output terminal, 130: infrared light receiving unit, 139: modem, 140
... Modem terminal, 150 ... CPU, 160 ... Auxiliary storage device, 170 ... Memory, 180 ... Data bus, 200 ... Monitoring camera, 210 ... Mobile phone, 220 ... Display
400 Remote control.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akira Nagasaka 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo F-term in Central Research Laboratory, Hitachi, Ltd. 5C053 FA06 FA12 FA23 FA25 FA27 GB06 GB21 GB36 JA22 KA03 KA22 KA24 KA26 LA06 LA15 5C054 CE16 DA09 EA01 EB02 EB05 EF06 EG05 EG06 FC01 GA01 GA04 GB05 GD05 HA18

Claims (13)

[Claims] 1. Sampling time setting means for setting a recording time interval, means for inputting and digitizing images in time series, and whether or not to record an input image at a sampling time according to a predetermined standard. The filtering means for determination, the image compression means for compressing the image determined to be "recorded" by the filtering means, the image recording means for recording the compressed image by adding input time information, and the image or image recording currently being input Video recording apparatus comprising: image display means for displaying one or more images stored in the means. 2. The filtering means according to claim 1, wherein a difference between an input image at a sampling time and an image recorded in the past is calculated, and when the difference exceeds a predetermined value, "recording" is performed. Video recording apparatus characterized by determining 3. A video recording apparatus according to claim 2, wherein the previously recorded image is an image recorded immediately before. 4. The method according to claim 2, wherein an average value of color or luminance is calculated for each block from the image, an absolute value of a difference between corresponding blocks of the two images is calculated, and a maximum value thereof is calculated. Video recording device characterized by the following: 5. A video recording apparatus according to claim 1, wherein the medium of the image recording means is one of a hard disk, a DVD-RAM, and a flash memory. 6. Sampling time setting means for setting a recording time interval, means for inputting images in time series, and filtering means for judging whether or not to record an input image at a sampling time according to a predetermined standard. Image recording means for adding input time information to an image determined to be "recorded" by the filtering means and recording the image, and an image currently displayed or one or more images displayed in the image recording means Video recording apparatus comprising display means 7. The filtering means according to claim 6, wherein the degree of difference between the input image at the sampling time and the previously recorded image is calculated, and when the degree of difference exceeds a predetermined value, "recording" is performed. Video recording apparatus characterized by determining 8. A video recording apparatus according to claim 7, wherein the previously recorded image is an image recorded immediately before. 9. The method according to claim 7, wherein an average value of color or luminance is calculated for each block from the image, and an absolute value of a difference between corresponding blocks of the two images is calculated. Video recording device characterized by the value 10. The medium of the image recording means according to claim 6,
Video recording device characterized by being one of hard disk, DVD-RAM and flash memory 11. A step of storing an input image from a surveillance camera in a memory on a computer-readable recording medium on which a control program of a video recording apparatus is recorded, wherein a difference between an image registered in the past and the input image is determined. Calculating the degree of difference, determining whether the degree of difference is greater than a predetermined threshold value, and, if so, registering the input image in a recording medium. Recording medium. 12. The computer-readable recording medium according to claim 11, further comprising a step of displaying a registered image on a display. 13. The computer-readable recording medium according to claim 11, wherein said step of determining the degree of difference includes a step of dividing the input image into blocks and calculating an average value of luminance in each block. When,
For each block, calculating the absolute difference between the average value of the brightness of the image registered immediately before and the average value of the brightness of the input image, and calculating the maximum value of the absolute difference in each block And setting the maximum value to the degree of difference.