JP2003111061A - Moving body detector, moving body detection system and moving body detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a moving body at a low cost. SOLUTION: An MPEG encoder 11 uses in-frame (or in-field) coding to compress moving picture data, a data quantity detection means 13 detects a quantity of moving picture data compressed by the MPEG encoder 11, a decision means 14 extracts the data quantity for inter-frame (or inter-field) coding among the data quantity detected by the data quantity detection means 13 and decides whether or not a moving body exists in the moving picture on the basis of the extracted data quantity at the inter-frame (or inter-field) coding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving body detecting device, a moving body detecting system and a moving body detecting method for detecting a moving body existing in a moving image.

[0002]

2. Description of the Related Art When a moving body is detected at a certain place, a monitoring camera or a monitoring device has been proposed which has a moving body detecting function for photographing the place or the moving body and transmitting a warning signal.

As such a conventional monitoring device, there is one described in Japanese Patent Application Laid-Open No. 11-18073. This conventional monitoring device is based on JPEG (Joint Photographic Exper
ts Group) method, a television signal is sequentially stored in a field memory for each field corresponding to a subject and compressed, and the data size of image data compressed by the JPEG method and the data size of previously compressed image data When the difference between the two is greater than or equal to a predetermined value, it is determined that the subject has moved.

[0004]

[Problems to be Solved by the Invention] However, JPE
The G method is originally an image compression method for still images, and in order to handle a moving image as a still image for each field, as in the above-described conventional monitoring apparatus, moving image data for each one field is recorded. It is necessary to store in the memory once and to compress the moving image data for one field stored in the field memory as still image data by the JPEG encoder. In addition to the JPEG encoder, the field memory is required, which reduces the cost of the apparatus. There is a problem that it is difficult to reduce.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a moving body detecting device, a moving body detecting system, and a moving body detecting method capable of detecting a moving body at low cost. To do.

[0006]

In order to solve the above problems, the moving object detecting apparatus of the present invention compresses moving image data by using intra-frame or intra-field coding and inter-frame or inter-field coding. Data compression means, a data amount detection means for detecting the data amount of the moving image data compressed by the data compression means, and a data amount detected by the data amount detection means, which is used for inter-frame or inter-field encoding. And a determination unit that determines the amount of data and determines whether or not a moving object exists in the moving image based on the extracted amount of data during inter-frame or inter-field encoding.

When this moving object detecting device is used, the moving object is directly detected from the moving image data, so that a frame buffer or the like for generating still image data from the moving image data is not required, and the moving object is detected at low cost. be able to.

Further, in the moving object detecting device of the present invention, in addition to the moving object detecting device of the above invention, the determination means detects the intra-frame or intra-field coding period in the moving image data and performs the intra-frame or intra-field coding. When it is not a period, it is determined to be inter-frame or inter-field coding, and the amount of data at that inter-frame or inter-field coding is extracted.

By using this moving object detecting apparatus, it is possible to accurately extract the amount of data when encoding between frames or between fields.

Further, in addition to the moving body detecting apparatus of each of the above inventions, the moving body detecting apparatus of the present invention is characterized in that the determination means determines the data amount at the time of inter-frame or inter-field encoding to be inter-frame or inter-field encoding. It is configured to accumulate in consecutive periods and determine whether or not a moving object exists in the moving image based on the accumulated value of the data amount.

By using this moving object detecting device, it is possible to accurately distinguish a temporary image disturbance such as noise from a moving object, and it is possible to accurately detect the presence of the moving object. it can.

Further, in the moving object detecting apparatus of the present invention, in addition to the moving object detecting apparatus of each of the above-mentioned inventions, the determination means performs unidirectional interframe or interfield coding and bidirectional interframe or interfield coding. The threshold is changed according to the ratio, and it is determined whether or not a moving object exists in the moving image based on the threshold.

By using this moving object detecting device, the presence of a moving object can be detected more accurately.

Further, in the moving object detecting device of the present invention, in addition to the moving object detecting device of each of the above inventions, the data compression means is MPEG.
The moving image data is compressed by the method.

When this moving object detecting device is used, a general-purpose M
A PEG encoder chip or the like can be used as data compression means, and the device can be realized at a lower cost.

The moving object detection system according to the present invention includes a photographing means for photographing a predetermined position and outputting moving image data, and moving image data by the photographing means for intra-frame or intra-field coding and inter-frame or inter-field coding. A photographing side device having a data compressing means for using and compressing, and a transmitting means for transmitting the moving image data compressed by the data compressing means, and the compressed moving image data transmitted from the transmitting means of the photographing side device. Receiving means, a data amount detecting means for detecting the data amount of the moving image data after compression received by the receiving means, and an inter-frame or inter-field code among the data amounts detected by the data amount detecting means. The amount of data at the time of encoding is extracted, and a moving object exists in the moving image based on the extracted amount of data at the time of inter-frame or inter-field encoding. And a moving object detection device including a determination means for determining whether Luke.

When this moving object detection system is used, the moving object is directly detected from the moving image data, so that a frame buffer or the like for generating still image data from the moving image data is not required, and the moving object is detected at low cost. be able to.

The moving object detecting method of the present invention comprises a step of compressing moving image data using intra-frame or intra-field encoding and inter-frame or inter-field encoding, and inter-frame or inter-field in the compressed dynamic image data. Detecting the amount of data at the time of encoding,
Determining whether or not a moving object exists in the moving image based on the detected data amount.

When this moving object detection method is used, the moving object is directly detected from the moving image data, so that a frame buffer or the like for generating still image data from the moving image data is not required, and the moving object is detected at low cost. be able to.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1. FIG. 1 is a block diagram showing the configuration of a moving body detection system according to Embodiment 1 of the present invention. In FIG. 1, a camera 1 is a photographing means for photographing a predetermined position and outputting moving image data. Motion detection device 2
Is a device that detects a moving object in a moving image based on the data of the moving image captured by the camera 1.

In the moving body detecting device 2, the MPEG encoder 11 encodes the moving image data from the camera 1 into MPEG.
(Moving Picture Experts Group) This is a circuit for compression. That is, the MPEG encoder 11 is a data compression unit that compresses moving image data using intra-frame (or field) encoding and inter-frame (or field) encoding. The MPEG system includes MPEG1, MPEG2, and MPEG4.

The transmitting means 12 is a circuit for transmitting the compressed moving image data and transmitting the judgment result of the judging means 14 to the monitoring device 3.

The data amount detecting means 13 is an MPEG.
This is a circuit that detects the data amount per frame (or field) of the moving image data compressed by the encoder 11.

Further, the judging means 14 extracts the data amount at the time of interframe (or field) encoding from the data amount detected by the data amount detecting means 13, and at the time of the extracted interframe (or field) encoding. It is a circuit that determines whether or not a moving object exists in a moving image based on the data amount of.

In the monitoring device 3, the receiving means 21 receives the moving image data from the moving body detecting device 2 and the notification (the determination result of the determining means 14) indicating that the moving body is detected, and the recording means 22 receives the notification. This is a device for recording notifications and moving image data, and for notifying a worker or the like of detection of a moving body by the notification means 23.

The recording means 22 is, for example, a device such as a hard disk device that stores data, a printer that prints a notification, or the like. In addition, the notification unit 23 is a display that displays that a moving object has been detected, a siren that sounds an alarm, a speaker, or the like.

Next, the operation of the above system will be described.

The camera 1 captures an image at a predetermined position,
Outputs moving image data. The MPEG encoder 11 of the moving body detection device 2 compresses the moving image data by the MPEG method and outputs the compressed moving image data.

The data amount detecting means 13 sequentially detects the data amount per frame (or field) in the compressed moving image data and outputs it.

Then, the judging means 14 extracts the data amount of the period corresponding to the P picture and the B picture from the data amount per frame (or field), and based on the extracted data amount, It is determined whether or not a moving object exists.

In the MPEG system, a P picture is a picture after compression by unidirectional interframe (or field) coding, and a B picture is compressed by bidirectional interframe (or field) coding. It is a later picture. In addition, I-pictures exist as pictures after compression by intra-frame (or field) coding. The I-picture data amount by intra-frame (or field) encoding is large, and the P-picture and B-picture data amount by inter-frame (or field) encoding is smaller than the I-picture data amount.

FIG. 2 is a diagram showing an example of a temporal change of the data amount of the compressed moving image data output from the MPEG encoder 11 in FIG. When the I picture is output, as at times T1, ..., T5 shown in FIG.
The amount of data per frame (or field) is large. On the other hand, when P picture or B picture is output,
As in the periods ΔT1, ..., ΔT4 shown in FIG. 2, the data amount per frame (or field) is smaller than the data amount of the I picture.

Further, P pictures and B pictures by inter-frame (or field) encoding are generated by encoding the change of the subject from the previous frame or field, or the preceding and following frames or fields. Therefore, when there is a large change in the subject from the previous frame or field, or the previous or next frame or field, the data amount of the P picture or B picture increases.

Therefore, when there is almost no change in the subject, that is, when there is no moving object, the data amount of the P picture or B picture becomes small as in the period ΔT1 shown in FIG.

On the other hand, when a relatively small moving object is present in the moving image, the data amount of the P picture or B picture becomes slightly large as in the period ΔT2 shown in FIG. Then, when a relatively large moving object is present in the moving image, the data amount of the P picture or the B picture is further increased as in the period ΔT3 shown in FIG. In addition, when a moving object is momentarily present in the moving image or when the image is momentarily disturbed by noise, the data amount of the P picture or the B picture is temporarily increased as in the period ΔT4 shown in FIG. Become.

From the compressed moving picture data, P picture and B picture
When detecting the period corresponding to the picture, the determination means 14
Is determined to be, for example, a period having a data amount equal to or less than a predetermined value as a period corresponding to a P picture and a B picture, or synchronized with an I picture having a peak data amount of compressed moving image data. The period other than the time corresponding to the I picture is determined to be the period corresponding to the P picture and the B picture.

Further, in the case of the MPEG system, since the P picture and the B picture are inter-frame (or field) encoded data, the data amount detecting means 13 causes the picture for each picture in the compressed moving image data to be a picture. The picture type may be discriminated from the value of the "picture coding type" code in the header, and the determination unit 14 may detect the period corresponding to the P picture and the B picture based on the picture type.

The determination means 14 detects the period corresponding to the P picture and the B picture in this way, and, for example, accumulates the amount of data in this period, and if the accumulated value is a predetermined value or more, the moving object It is determined that the moving body exists, and if the cumulative value is smaller than the predetermined value, it is determined that the moving body does not exist.

Then, the judging means 14 sends the judgment result to the transmitting means 12 in order to notify the monitoring device 3 of the judgment result.
Supply to.

The transmitting means 12 transmits the judgment result to the monitoring device 3 together with the compressed moving image data. The determination result and the moving image data after compression may be transmitted by wire or wirelessly, and a dedicated line or a telephone line may be used as the transmission medium.

At this time, the transmitting means 12 may transmit the determination result and the compressed moving image data to the monitoring device 3 only when a moving body is detected.

The receiving means 21 of the monitoring device 3 receives the determination result from the moving object detecting device 2 and the compressed moving image data,
The recording unit 22 records the received determination result and the compressed moving image data. When the determination result indicating that the moving body is detected is received, the notification unit 23 notifies the worker or the like to that effect.

The monitoring device 3 includes an MPEG decoder,
An image processing circuit, a display, or the like may be provided to decompress the received moving image data and display the captured moving image on the display online or offline.

Further, in FIG. 1, the camera 1 and the moving body detecting device 2 are separately provided, but the camera 1 and the moving body detecting device 2 are separated from each other.
May be built in.

Further, when P pictures and B pictures coexist, the judging means 14 may change the threshold value at the time of moving object detection judgment according to the ratio of P pictures and B pictures.

Further, in the first embodiment, one camera 1 and one moving object detection device 2 are provided for each monitoring device 3, but one monitoring device 3 is provided for each monitoring device 3.
You may make it provide several cameras 1 and the moving body detection apparatus 2.

As described above, according to the above-described first embodiment, the moving body detection device 2 is configured so that the frame (or field) is
An MPEG encoder 11 for compressing moving image data using inner coding and inter-frame (or field) coding, and a data amount detecting means 13 for detecting the amount of moving image data compressed by the MPEG encoder 11.
Of the data amount detected by the data amount detecting means 13, the data amount at the time of interframe (or field) encoding is extracted, and the extracted frame (or field) is extracted.
A determination unit 14 that determines whether or not a moving object exists in the moving image based on the amount of data at the time of inter-coding. With this, since the moving object is directly detected from the moving image data,
A frame buffer or the like for generating still image data from moving image data is unnecessary, and moving objects can be detected at low cost.

Further, according to the first embodiment, the determination means 14 of the moving body detection device 2 detects the intra-frame (or field) coding period (I picture period) in the moving image data, and the frame ( Frame (or field) when it is not the intra coding period
It is determined that it is during inter-coding (at the time of P picture and B picture), and the amount of data at that inter-frame (or field) coding is extracted. As a result, it is possible to accurately discriminate a temporary image change such as noise from a moving body, and to accurately detect the presence of the moving body.

Further, according to the first embodiment, the determination means 14 of the moving body detection device 2 performs the unidirectional interframe (or field) coding and the bidirectional interframe (or field) encoding. The threshold is changed according to the ratio, that is, the ratio of the P picture and the B picture, and it is determined whether or not a moving object exists in the moving image based on the threshold. As a result, the presence of the moving body can be detected more accurately.

Furthermore, according to the first embodiment, the MPEG encoder 11 is used as the data compression means for compressing the moving image data. As a result, a general-purpose MPEG encoder chip or the like can be used as data compression means,
The device can be realized at a lower cost.

Embodiment 2. The moving body detection system according to the second embodiment of the present invention is configured to perform moving body detection on the receiving side of moving image data.

FIG. 3 is a block diagram showing the structure of a moving body detection system according to the second embodiment of the present invention. In FIG. 3, the photographing side device 31 is a device that compresses the moving image data photographed by the camera 1 by the MPEG encoder 11 and transmits the compressed moving image data by the transmitting means 12.

The moving object detecting device 2A is a device for receiving moving image data after compression and detecting a moving object in the moving image based on the received data amount.

In the moving body detecting device 2A, the receiving means 41
Is a circuit for receiving the compressed moving image data transmitted from the transmitting means 12 of the photographing side device 31. Further, the recording unit 42 is a device for recording the compressed moving image data and the determination result of the determination unit 44, like the recording unit 22 of FIG.

The data amount detecting means 43 is a circuit for detecting the data amount of the compressed moving image data received by the receiving means 41. Further, the determination unit 44 extracts the data amount at the time of inter-frame (or field) encoding from the data amount detected by the data amount detection unit 43, and the extracted data at the time of inter-frame (or field) encoding. It is a circuit that determines whether or not a moving object exists in a moving image based on the amount. Further, the notification means 45 is a device which, like the notification means 23 of FIG. 1, notifies the worker or the like of the fact that a moving body is detected by the determination means 44.

Next, the operation of the above system will be described.

The camera 1 captures an image at a predetermined position,
Outputs moving image data. The MPEG encoder 11 of the moving body detection device 2 compresses the moving image data by the MPEG method and outputs the compressed moving image data. The transmission means 12 of the moving body detection device 2 transmits the compressed moving image data to the moving body detection device 2A.

The receiving means 41 of the moving body detecting device 2A receives the compressed image data transmitted from the moving body detecting device 2 and supplies it to the data amount detecting means 43 and the recording means 42. The data amount detecting means 43 sequentially detects the data amount per frame (or field) in the compressed moving image data and outputs it. Then, the determination means 44
Is similar to the determination means 14 in the first embodiment,
From the data amount per frame (or field), the data amount in the period corresponding to the P picture and the B picture is extracted, and it is determined whether or not a moving object exists in the moving image based on the extracted data amount. To do.

The determination means 44 informs the determination result of the determination result.
5 and the recording means 42. When the moving body is detected, the notifying unit 45 notifies the worker or the like to that effect, and the recording unit 42 records the determination result together with the compressed moving image data.

As described above, according to the second embodiment, the same effect as that of the first embodiment can be obtained.

An MPEG decoder, an image processing circuit, a display, etc. are provided in the moving body detecting device 2A to expand the received moving image data and display the taken moving image on the display online or offline. May be.

Further, in FIG. 3, the camera 1 and the photographing side device 31 are separated, but the camera 1 and the photographing side device 31 are separated from each other.
May be built in.

Further, in the second embodiment, one camera 1 and one photographing side device 31 are provided for one moving object detecting device 2A, but one moving object detecting device 2 is provided.
For A, each of the plurality of cameras 1 and the photographing side device 31
May be provided. In that case, even if a plurality of cameras 1 and photographing side devices 31 are provided, only one data amount detection means 43 and one determination means 44 are required, so that the moving object detection system can be realized at low cost.

Embodiment 3. The moving body detection device according to the third embodiment of the present invention is one in which the function of the monitoring device 3 according to the first embodiment is built in the moving body detection device 2.

FIG. 4 is a block diagram showing the structure of a moving body detecting apparatus according to the third embodiment of the present invention. The moving body detection device 2B according to the third embodiment of the present invention detects a moving body in a moving image from the data of the moving image captured by the camera 1,
When a moving body is detected, the moving image is recorded by the recording means 51, the fact is transmitted, and a notification is given.

In the moving body detecting apparatus 2B shown in FIG. 4, the recording means 51 is an apparatus for recording the moving image data after compression and the judgment result of the judging means 14 like the recording means 22 of FIG.

Further, the transmitting means 52 is a circuit for transmitting a notification to that effect to a remote worker when the moving body is detected by the judging means 14.

The notifying means 53 is the notifying means 2 of FIG.
Similar to 3, when the determination unit 14 detects a moving body, the determination unit 14 notifies the worker or the like to that effect.

Since the other constituent elements in FIG. 4 are the same as those in the first embodiment, the description thereof will be omitted.

Next, the operation of the above apparatus will be described.

The moving body detecting device 2B according to the third embodiment is
The moving image data compressed by the MPEG encoder 11 and the determination result by the determination unit 14 are recorded by the recording unit 51.

Further, the moving body detection device 2 according to the third embodiment
When a moving body is detected, B informs the worker or the like by means of the notification means 53, or transmits the notification to the worker or the like at a distance by the transmission means 52, for example, through a telephone line or the like. To do.

Since the other operations are the same as those of the moving body detecting device 2 in the first embodiment, the description thereof will be omitted.

The moving object detecting device 2B is provided with an MPEG decoder, an image processing circuit, a display, etc. to expand the received moving image data and display the taken moving image on the display online or offline. May be.

As described above, according to the third embodiment, the same effect as that of the first embodiment can be obtained.

[0077]

According to the present invention, it is possible to obtain a moving body detecting device, a moving body detecting system and a moving body detecting method which can detect a moving body at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a moving body detection system according to a first embodiment of the present invention.

2 is a diagram showing an example of a temporal change in a data amount of compressed moving image data output from the MPEG encoder in FIG.

FIG. 3 is a block diagram showing a configuration of a moving body detection system according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a moving body detection device according to a third embodiment of the present invention.

[Explanation of symbols]

1 camera (shooting means) 2,2A, 2B Motion detection device 11 MPEG encoder (data compression means) 12 Transmission means 21,41 Receiving means 13,43 Data amount detection means 14,44 Judging means

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Claims (7)

[Claims] 1. A data compression means for compressing moving image data using intra-frame or intra-field encoding and inter-frame or inter-field encoding, and a data amount of the dynamic image data compressed by the data compression means. Data amount detecting means for detecting, and of the data amounts detected by the data amount detecting means, the data amount at the time of interframe or interfield encoding is extracted, and the extracted data at the time of interframe or interfield encoding A moving body detection device comprising: a determination unit that determines whether or not a moving body exists in a moving image based on the amount. 2. The determining means detects an intra-frame or intra-field coding period in the moving image data, and defines a time when the intra-frame or intra-field coding period is not the inter-frame or inter-field coding time. The moving object detecting apparatus according to claim 1, wherein the moving amount detecting apparatus determines the data amount and extracts the data amount during the inter-frame or inter-field encoding. 3. The determination means accumulates the extracted data amount at the time of inter-frame or inter-field encoding in a period in which the inter-frame or inter-field encoding is continuous, and based on the accumulated value of the data amount. The moving object detecting device according to claim 1 or 2, wherein it is determined whether or not a moving object exists in the moving image. 4. The determination means changes a threshold value according to a ratio of inter-frame or inter-field encoding in one direction and bi-directional inter-frame or inter-field encoding, and a moving image based on the threshold value. The moving body detection device according to claim 1, wherein it is determined whether or not a moving body exists therein. 5. The moving object detecting device according to claim 1, wherein the data compressing unit compresses moving image data by an MPEG method. 6. A photographing means for photographing a predetermined position and outputting moving image data, and compressing the moving image data by the photographing means by using intra-frame or intra-field coding and inter-frame or inter-field coding. And an image capturing side device having a transmitting means for transmitting the moving image data compressed by the data compressing means, and the compressed moving image data transmitted from the transmitting means of the image capturing side device. Receiving means for receiving, data amount detecting means for detecting the data amount of the compressed moving image data received by the receiving means, and among the data amounts detected by the data amount detecting means, between frames or Extracts the amount of data for inter-field coding and displays it in the moving image based on the extracted amount of data for inter-frame or inter-field coding. Motion detection system comprising: the moving object detection device including a determination means for determining whether the body is present, the. 7. A step of compressing moving image data using intra-frame or intra-field encoding and inter-frame or inter-field encoding, and a data amount at the time of inter-frame or inter-field encoding in the compressed moving image data. And a step of determining whether or not a moving body exists in the moving image based on the detected amount of data, a moving body detection method.