JP2004112005A - Image recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording system and a reproducing system for an image recorder in which the burden of a confirming work can be lessened. <P>SOLUTION: A recording section 31 records an image photographed by means of a camera 4 constantly in a storage means 34. A variation point is judged for each frame image and specific information and variation level of the frame image are recorded in an index file 351 when a variation point is judged. The variation level is defined by the ratio of a variation occurring area to an effective area. A reproducing section 32 has two reproduction systems. One system sequentially reproduces frame images recorded as variation points in the index file 351. Another system sequentially reproduces the frame images at the head of the frame images recorded continuously as variation points. Furthermore, the reproducing section 32 performs reproduction depending on the variation level when it is specified. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a recording method and a reproducing method of an image captured by a camera.
[0002]
[Technical background and issues]
There is an image recording device for monitoring using a hard disk or the like. A camera is installed in a monitoring area such as a store, and images taken by the camera are sequentially stored in a storage unit such as a hard disk.
[0003]
In such an image recording apparatus, since it is necessary to constantly monitor the inside of the monitoring area, it is necessary to always store the captured image in the storage unit even when the state in the monitoring area does not change. Then, when an abnormality occurs, the image recorded by the image recording apparatus is reproduced later to observe the state in the monitoring area.
[0004]
However, when it is not possible to specify the time zone in which the abnormality has occurred, it is necessary to reproduce and check all the images recorded by the image recording apparatus, and a long time is required for the checking operation.
[0005]
SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an image recording apparatus provided with an image recording method and a reproduction method that can easily confirm an image photographed by a camera.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is a recording device for recording an image captured by a camera, comprising: an image recording means for constantly recording a frame image continuously input from the camera; And index recording means for recording, as index information, a change point of the input frame image.
[0007]
According to a second aspect of the present invention, in the image recording apparatus according to the first aspect, the index recording unit determines that the change point occurs when the ratio of the change occurrence area to the effective area of the frame image exceeds a predetermined threshold. Means.
[0008]
According to a third aspect of the present invention, in the image recording apparatus according to the second aspect, the effective area is a mask area designated in advance as a change point extraction target from all areas of the frame image input from the camera. The feature is that the area is excluded.
[0009]
According to a fourth aspect of the present invention, in the image recording apparatus according to any one of the first to third aspects, when the image recorded by the image recording means is reproduced, the index information is referred to. Means for sequentially reproducing only the frame images recorded as the change points.
[0010]
According to a fifth aspect of the present invention, in the image recording apparatus according to any one of the first to fourth aspects, when the image recorded by the image recording unit is reproduced, the index information is referred to. Means for sequentially reproducing only the first frame image among the frame images recorded continuously as change points.
[0011]
According to a sixth aspect of the present invention, in the image recording apparatus according to any one of the first to fifth aspects, the index recording unit records a ratio of a change occurrence area to an effective area of a frame image as a change level. The image recording apparatus further comprises: when reproducing the image recorded by the image recording means, by referring to the index information, the designated change in the frame image recorded as a change point. Means for sequentially reproducing only the frame images at the change points equal to or higher than the level.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
<Overall configuration and processing overview>
As shown in FIG. 1, a camera 4 is installed in a monitoring area 1, and an image captured by the camera 4 is transferred to an image recording device 3 installed in a monitoring room 2 via a cable. A monitor 5 is connected to the image recording device 3 so that an image recorded by the image recording device 3 can be reproduced and displayed.
[0014]
The surveillance area 1 is, for example, inside a convenience store, and the camera 4 takes pictures of the inside of the store, for example, around the clock. Then, the image recording device 3 constantly records the image input from the camera 4. The monitoring room 2 may be located at a remote location remote from the monitoring area 1, and the image captured by the camera 4 may be transferred via a network.
[0015]
FIG. 2 is a diagram illustrating a functional block configuration of the image recording device 3. The image recording device 3 includes a recording unit 31 and a reproducing unit 32.
[0016]
The recording unit 31 has a function of inputting an image captured by the camera 4 and storing the input image in the storage unit 34 as image data 341. Further, the recording unit 31 has a function of writing index information to the index file 351 stored in the storage unit 35. The storage means 34 and 35 are composed of, for example, hard disks.
[0017]
The reproduction unit 32 has a function of reproducing the image data 341 stored in the storage unit 34 while referring to the index file 351. The image data 341 is a set of frame images continuously captured by the camera 4. Therefore, the reproducing unit 32 has a function of reproducing the image data 341 as a moving image.
[0018]
<Change point judgment and index file>
Next, a method of determining a change point and the index file 351 will be described. The recording unit 31 includes a change point determination unit 311. The change point determination unit 311 is a functional unit that detects a change point of a continuously input image captured by the camera 4.
[0019]
The determination of the change point is determined by the ratio of the change occurrence area CA to the effective area EA shown in FIG. Here, the effective area EA is an area obtained by removing the mask area MA from the entire area of the frame image captured by the camera 4. In the figure, the area indicated by oblique lines is the mask area MA, and the area other than the oblique lines is the effective area EA. A range surrounded by a broken line is a change occurrence area CA.
[0020]
For example, it is assumed that a window glass exists in the entire shooting area. In this case, the outside scene taken through the window glass is not monitored. That is, when a change point is detected even for a scene outside the window, a movement of a person outside the monitoring area is detected, and a useless check operation is performed. Therefore, an area excluding the mask area MA from all areas is to be monitored.
[0021]
As a method of determining the change occurrence area CA, for example, there is a method of using difference information between frame images. For the effective area EA divided into blocks, a difference is calculated for luminance information between frame images for each block. More specifically, a method of calculating a difference between frames for luminance information of each pixel in a block, and taking an average of differences (or a sum of differences) in the block can be used. Then, when the difference value exceeds a certain threshold value, the block is recognized as a changed block and included in the change occurrence area CA. Then, by adjusting the value of the threshold value, it is possible to adjust and determine the changed block. For example, by setting the threshold value to be low, it is possible to make an adjustment to increase the determination sensitivity of the changed block.
[0022]
In the example shown in the figure, the ratio of the change occurrence area CA to the effective area EA is 0.2 because the effective area EA is 20 blocks and the change occurrence area CA is 4 blocks. . That is, the change level is 0.2. Here, for convenience, a value obtained by multiplying this ratio by 10 is used as a change level. In the example of the figure, the change level is 2.
[0023]
In this way, the change point determining unit 311 determines whether or not a change has occurred in each block in the effective area EA. Then, when the change occurrence area CA exists in the effective area EA, the recording unit 31 records the specific information and the change level of the current frame image in the index file 351 as index information.
[0024]
FIG. 4 is a diagram showing an example of the contents of the index file 351. In the index file 351, a frame number and a change level are recorded as index information. As the specific information of the frame image, as shown in the figure, a frame number sequentially added to the frame image is used, or time information can be used.
[0025]
As described above, by referring to the index file 351, it is possible to obtain information such as which frame image has a change in the image and the level of the change.
[0026]
The above-described image recording method will be specifically described with reference to FIG. FIG. The contents of seven continuous frame images 1002141 to 1002147 are shown.
[0027]
First, the first frame No. The image 1002141 has no change from the previous frame image (not shown). In this case, no index information is recorded in the index file 351 because the change occurrence area CA does not exist.
[0028]
Next, the second frame No. In the image of 1002142, a person appears and a change occurs in the image. In the figure, the change occurrence area CA is indicated by a broken line. At this time, it is assumed that the change level of the image is calculated as 2 by the change point determining unit 311. As a result, as shown in FIG. 1002142 and change point level 2 are recorded.
[0029]
Next, the third frame No. In 1002143, the change occurrence area CA expands according to the movement of the person. As a result, as shown in FIG. 1002143 and change point level 5 are recorded.
[0030]
Similarly, the fourth frame No. 1002144, the change level 5 is the fifth frame No. In 1002145, the change level 4 is recorded in the index file 351.
[0031]
Next, the sixth frame No. In 1002146, the change of the image occurs due to the disappearance of the shadow, and the change level 2 is recorded in the index file 351.
[0032]
Then, the seventh frame No. In the image 1002147, there is no change from the sixth frame image, so that the change occurrence area CA does not exist, and no index information is recorded in the index file 351.
[0033]
Thus, the frame No. The five frame images 1002142 to 1002146 are determined to be change points, and index information is recorded in the index file 351.
[0034]
<Playback processing>
Next, a reproduction process of a recorded image will be described. The reproduction unit 32 executes a recording image reproduction process in response to an instruction from the designation unit 33. The designation unit 33 instructs the reproduction unit 32 to reproduce an image in response to an instruction from an operation button, a remote control, or the like included in the image recording device 3.
[0035]
There are two types of image reproduction methods, and the specification unit 33 receives an operation instruction such as an operation button and specifies which reproduction method to use for the reproduction unit 32.
[0036]
The first reproduction method is a sequential reproduction method of changing points. This method is a method of sequentially reproducing frame images in which the change occurrence area CA exists among the image data 341 stored in the storage means 34. That is, this is a method of reproducing the frame images of all the frame numbers recorded in the index file 351.
[0037]
By using this reproduction method, the user can check only the changed image. This makes it possible to reduce the burden of the checking operation. For example, in the example shown in FIG. Five images from No. 1002142 to No. 1002146 are reproduced. The images 1003051 and 1003052 are reproduced.
[0038]
The second playback method is a method of playing back the first frame image among the frame images continuously recorded as a change point. In other words, in a case where frame images in which the change occurrence area CA exists continuously exist, the first change point image is reproduced.
[0039]
By using this reproduction method, the user can check only the changed image. Furthermore, when the changed images are continuously present, only the first image is reproduced, so that a quick confirmation operation can be performed. For example, in the example shown in FIG. The image of No. 1002142 is reproduced. The image of 1003051 is reproduced.
[0040]
In addition, the specifying unit 33 can specify a change level of an image to be reproduced. The designation unit 33 designates a change level of an image to be reproduced for the reproduction unit 32 in response to an instruction from an operation button or the like.
[0041]
In the example shown in FIGS. 4 and 5, for example, if the designated change level is 2, the frame No. No. 1002142 to 1002146 and five frame images and frame Nos. The frame image 1003051 is to be reproduced. On the other hand, if the designated change level is 5, the frame No. Two images 1002143 and 1002144 are to be reproduced.
[0042]
In this manner, by specifying the change level at the time of reproduction, image reproduction can be performed while selecting the change level (detection sensitivity) of the frame image to be reproduced. The user specifies the change level in ten steps from 1 (high sensitivity) to 10 (low sensitivity), for example, using the operation buttons and the like. As a result, it is possible to use a method in which the change level is first increased, the image of the greatly changed portion is confirmed, and then the small change is confirmed while decreasing the change level. Thereby, an efficient checking operation can be performed.
[0043]
【The invention's effect】
As described above, according to the first aspect of the present invention, since a change point of an image is recorded as index information together with an image, it is possible to specify a changed image from images that are constantly recorded.
[0044]
According to the second aspect of the present invention, since the change point is determined from the ratio of the change occurrence area in the effective area, it is possible to quantitatively grasp the degree of occurrence of the change.
[0045]
According to the third aspect of the present invention, since the area excluding the change point extraction target is set as the effective area, it is possible to accurately determine only the meaningful change occurrence.
[0046]
According to the fourth aspect of the present invention, since only the frame images recorded as the change points are sequentially reproduced, it is possible to reduce the burden of the checking operation.
[0047]
According to the fifth aspect of the present invention, since only the head of the continuously existing change point images is reproduced, a quick confirmation operation can be performed.
[0048]
According to the sixth aspect of the present invention, since the reproduction in which the change level is designated is possible, the change detection sensitivity of the image to be reproduced can be adjusted according to the purpose.
[Brief description of the drawings]
FIG. 1 is a diagram showing an installation mode of a camera and an image recording device installed in a monitoring area.
FIG. 2 is a functional block diagram of the image recording apparatus.
FIG. 3 is a diagram illustrating an effective area, a change occurrence area, and the like of a frame image.
FIG. 4 is a diagram showing a registration example of index information.
FIG. 5 is a diagram showing an example of frame images shot continuously.
[Explanation of symbols]
3 Image recording device 4 Camera 5 Monitor 31 Recording unit 32 Reproduction unit 33 Designation unit 311 Change point determination unit 341 Image data 351 Index information CA Change occurrence area EA Effective area MA Mask area

Claims (6)

A recording device for recording an image taken by a camera,
Image recording means for constantly recording a frame image continuously input from the camera,
Index recording means for recording a change point of a continuously input frame image as index information,
An image recording apparatus comprising: The image recording apparatus according to claim 1,
The index recording means,
Means for determining a change point when the ratio of the change occurrence area to the effective area of the frame image exceeds a predetermined threshold,
An image recording apparatus comprising: The image recording apparatus according to claim 2,
The image recording apparatus according to claim 1, wherein the effective area is an area obtained by excluding a mask area which has been designated in advance as a change point extraction target from all areas of a frame image input from the camera. The image recording apparatus according to any one of claims 1 to 3, further comprising:
Means for sequentially reproducing only frame images recorded as change points by referring to the index information when reproducing the image recorded by the image recording means,
An image recording apparatus comprising: The image recording apparatus according to any one of claims 1 to 4, further comprising:
When reproducing the image recorded by the image recording means, by referring to the index information, of the frame images continuously recorded as a change point, means for sequentially reproducing only the first frame image,
An image recording apparatus comprising: An image recording apparatus according to any one of claims 1 to 5,
The index recording means,
Means for recording the ratio of the change occurrence area to the effective area of the frame image as a change level,
Including
The image recording device further includes:
When reproducing the image recorded by the image recording means, by referring to the index information, only the frame images at the change points higher than the designated change level among the frame images recorded as the change points are sequentially reproduced. Means to
An image recording apparatus comprising:

Images