JP2002171483A - Image reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To retrieve a motion part from an image recorded for a long time in a short time when detecting the motion part. SOLUTION: A motion detection section 3 capturing compressed image data recorded on a hard disk 2 detects a motion, the compressed image whose motion is detected is sent from the hard disk 2 to an image expansion processing section 4 to reproduce the image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reproducing apparatus capable of extracting and reproducing a moving image when reproducing an image recorded for a long time.

[0002]

2. Description of the Related Art In an image recording system for surveillance, there is a demand for searching and viewing only a portion of an image recorded for a long time after the image has been changed due to a human intrusion or the like.
Conventional systems of this type do not have that function.

Therefore, conventionally, when recording an image, various conditions such as an image sensor or the like are used to detect the surroundings, and an image of a portion where the sensor has operated or only images before and after the image has been recorded, or the sensor has operated. A time is recorded, and an image at the time is searched for and reproduced from a long-time recorded image.

[0004]

However, when only the part where the sensor operates is recorded, the image of the other part cannot be recorded, and the detection part of the sensor is changed to change the detection. It was not possible to reproduce an image having a change in a part, nor was it possible to change the sensitivity of change detection during reproduction and reproduce an image detected with that sensitivity.

It is an object of the present invention to provide an image reproducing apparatus which solves the above-mentioned problem by performing motion detection during reproduction.

[0006]

According to a first aspect of the present invention, there is provided a recording medium on which a compressed image is recorded, and a method for detecting motion by taking in compressed image data recorded on the recording medium. And a means for taking in the compressed image of which motion has been detected by the motion detecting means from the recording medium and expanding the image.

In a second aspect based on the first aspect, the image decompression means is configured to take in a compressed image before and after that including the compressed image detected by the motion detection means and decompress the image.

[0008] In a third aspect based on the first or second aspect, the compressed image is an image including recording time data, and the motion detecting means includes a compressed image recorded on the recording medium. Is configured to perform motion detection on an image during a designated time.

According to a fourth aspect of the present invention, in the first, second, or third aspect, there is provided means for displaying an image obtained by the image decompression means, and the display means displays a thumbnail of the input image. It was configured as follows.

[0010] In a fifth aspect based on the first, second, third, or fourth aspect, the motion detecting means is configured to perform motion detection for a designated portion.

In a sixth aspect, the first, second, third, fourth,
Alternatively, in the fifth invention, the motion detection means is configured so that its detection sensitivity is adjustable.

[0012]

FIG. 1 is a block diagram showing an embodiment of an image recording apparatus according to the present invention. Reference numeral 1 denotes an image compression processing unit for compressing a video signal of a monitoring area captured by a monitoring camera such as a CCD camera, and 2 a hard disk as a recording medium for recording image data compressed by the image compression processing unit 1. Reference numeral 3 denotes a motion detection unit which takes in the compressed image data read from the hard disk 2 and performs motion detection.
Is an image decompression processing unit that decompresses the compressed image data read from the hard disk 2 and converts it into the original video signal and outputs it. Is a control unit that controls A display such as a monitor is connected to a stage subsequent to the image memory 5.

A video signal of a surveillance image picked up by a fixed surveillance camera is compressed by an image compression processing unit 1 to be recorded as compressed image data on a hard disk 2, and compressed image data read from the hard disk 2 Is decompressed by the image decompression processing unit 4 and written into the image memory 5,
It is displayed on a display (not shown).

When reproducing an image having a predetermined or more motion from the compressed image data recorded on the hard disk 2, the control unit 6 controls the motion detection unit 3 to detect a detected portion (a specific detection area in the monitoring image). ) And detection sensitivity (the minimum amount of motion to be detected)
By reading out only the data necessary for motion detection from the compressed image data of (1) and fetching the data into the motion detection unit 3 and sequentially comparing the data of the preceding and succeeding images with respect to the compressed image data,
An image having a motion higher than the sensitivity set for the set detection site is detected. When a moving image is detected, the detection result is sent to the control unit 6, and the control unit 6 transfers the moving compressed image data to the hard disk 2.
To the image decompression processing unit 4 to perform decompression processing there,
Write to the image memory 5. In the image memory 5, the control unit 6
In accordance with the instruction from, the decompressed image is arranged in a display format such as a single screen display or a thumbnail display and output to a display device (not shown).

In the above description, the motion detection unit 3 needs to operate faster than the expansion operation of the image expansion processing unit 4. Therefore, in the present embodiment, a compression method that enables fast and simple motion detection, for example, a wavelet compression method, is used for the processing in the image compression processing unit 1 and the processing in the image expansion processing unit 4. This method employs (1). Decompose the original image into high and low frequency components, (2). Reduce the low frequency component to half the size of the image vertically and horizontally and further divide it into high frequency components and low frequency components (3). This is a method of obtaining the low frequency component by repeating the operation of (2) several times. By the operations (1) to (3), the lowest frequency component obtained is considerably smaller than the original image size (the number of image data). Therefore, high-speed motion detection is performed by comparing the preceding and succeeding images using the low-frequency component data in which the number of image data has been reduced.

In the above, if the data of the recording time is included in the compressed image data to be recorded on the hard disk 2, the detection range can be designated at the time of the motion detection by the motion detection section 3, and the time within the specific time range Motion detection can be performed only for an image. This is suitable for selectively performing nighttime motion detection on an image captured in a monitoring area in which many people enter and leave during the day but are small at night.

[0017]

As described above, according to the present invention, only a moving part of a recorded image can be extracted and displayed. Therefore, even when a moving part is detected from an image recorded for a long time, The search for the moving part can be performed in a short time. In addition, since the detection site, the detection sensitivity, and the detection time can be arbitrarily set at the time of reproduction, a search more suitable for the purpose can be performed. For example, if it is later found out that something on a specific shelf within the image range was stolen during image recording, the stolen image can be set by setting that shelf part as the detection site. Only the extracted information can be reproduced and displayed. In addition, a small moving portion can be ignored by setting the detection sensitivity. Further, only the movement at night can be detected by specifying the time.

[Brief description of the drawings]

FIG. 1 is a block diagram for implementing an image reproducing apparatus of the present invention.

FIG. 2 is an explanatory diagram of weblet compression.

[Explanation of symbols]

 1: Image compression processing unit 2: Hard disk 3: Motion detection unit 4: Image expansion processing unit 5: Image memory 6: Control unit

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 7/18 H04N 5/92 H

Claims (6)

[Claims] 1. A recording medium on which a compressed image is recorded,
Means for taking in the compressed image data recorded on the recording medium to perform motion detection, and means for taking in the compressed image whose motion is detected by the motion detection means from the recording medium and expanding the image. Image reproducing device. 2. The image reproducing apparatus according to claim 1, wherein said image decompressing means takes in a compressed image before and after that including the compressed image detected by said motion detecting means and decompresses the image. apparatus. 3. The image reproducing apparatus according to claim 1, wherein said compressed image is an image including recording time data, and said motion detecting means is a compressed image recorded on said recording medium. Wherein the motion detection is performed on an image during a designated time period. 4. An image reproducing apparatus according to claim 1, further comprising: means for displaying an image obtained by said image decompressing means, wherein said display means displays a thumbnail of the input image. Characteristic image reproducing device. 5. The image reproducing apparatus according to claim 1, wherein said motion detecting means detects a motion of a designated part. 6. An image reproducing apparatus according to claim 1, wherein said motion detecting means has an adjustable detection sensitivity.