JP2001103452A - Image transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a conventional image transmitter a monitoring camera, of which has been heavily loaded because of large arithmetic quantities required to obtain movement vectors. SOLUTION: A current image frame memory 3 stores an image signal from a monitoring camera 1 via an A/D converter 2. Furthermore, a reference image frame memory 5 also stores the image signal when updating a reference image by a reference image update device 4. An image signal converter 6 outputs a luminance signal obtained from the current image frame memory 3 and the reference image frame memory 5 to a binary processing section 7, where the difference data of the luminance signal of each image and the reference image data are compared to obtain binary processing data and a projection arithmetic section 9 obtains a projection value from the binary processing data. Furthermore, a difference discriminating section 9 decides the difference area, a center of gravity arithmetic section 10 calculates the gravity center of the difference area, a JPEG compression section 12 compresses the image data in the difference area after a movement discrimination section 11 calculates moving quantity and moving direction, and a data transmission section 12 transmits the compressed data together with the moving quantity, the moving direction and the data of the difference area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transmitting apparatus for transmitting moving image data by outputting difference image data with respect to a reference image, and more particularly, to moving image data picked up by an image pickup device such as a TV camera. The present invention relates to an image transmission apparatus suitable for performing remote monitoring by transmitting data via a transmission path.

[0002]

2. Description of the Related Art A conventional image transmission apparatus for remote monitoring includes:
Monitoring at a remote location has been made possible by transmitting and displaying moving image information captured by a monitoring camera directly to a monitoring monitor via a dedicated line or via a time plus VTR.
Here, conventionally, since the moving image data captured by the surveillance camera is transmitted as it is, an extremely wide transmission band is required, and it is necessary to connect each dedicated line to each surveillance camera. However, conventional image transmission devices that require a dedicated line for each surveillance camera are very costly, and if a transmission path with a wide transmission band cannot be obtained, reduce the number of transmission frames. , It was necessary to take some sort of information reduction technique.

When image information is compressed and transmitted in order to reduce the image information, TV conference systems and TV telephones use ITU-T H.261 or H.261, which is an international standard, as a compression encoding method for image data. .263 etc. are used. These compression methods use DCT (Discrete Cosine Transform)
, Image information can be compressed at a very high compression ratio by using frame prediction, motion detection, and the like. However, in these image transmission methods, the image quality of the decoded image is significantly degraded, and when one frame of the moving image information is displayed as a still image, the image quality becomes unbearable. There is no problem when only moving images are played back, such as a TV phone or TV conference system, or when the image quality requirement of still images is not tight. However, in the case of a monitoring device, not only the display of moving images but also the occurrence of abnormalities occurs. For confirmation, identification of the cause, and the like, a still image quality that can withstand visual recognition to some extent is required.

[0004] In order to solve such a problem, the surveillance apparatus calculates a change by image processing by comparing the change with a reference image in a surveillance area, and only the changed part is a frame such as JPEG. A method of transmitting data after performing internal compression has been considered. This compares the current image with the reference image to determine areas of change (difference areas)
In this method, the obtained image of the difference area is compressed as a difference image, transmitted, and combined with the reference image at the transmission destination to be displayed. The difference area is calculated by comparing data of each pixel of the current image and the reference image to calculate a difference value, and when the difference value is larger than a predetermined allowable value, the difference area is determined as a changed pixel. When a range in which the changed pixels are continuously present is equal to or larger than a predetermined size, the range is determined through a process such as a difference region.

In this method, it is possible to easily control a desired image quality by changing numerical values such as an allowable value and a continuous existence range, and to reduce the amount of image information to be transmitted without significantly lowering the image quality. Is possible. Further, when the changed image does not appear in a prosperous manner, it is also possible to use a telephone line or the like as a communication path and connect to the monitor monitor side and transmit the image only when transmitting the changed image.

Some of such remote monitoring devices track changes in the difference area in time series, and determine that the cause of the difference area is a moving object and sound an alarm.
In this method, the image pattern such as the density of the previous difference area is stored, the image pattern is searched from the peripheral portion of the previous difference area in the latest image, and the image patterns are compared while being shifted little by little, and the similarity is calculated. This is realized by, for example, extracting a high region, determining the cause of the previous difference region, and calculating a movement vector from position information of the region.

[0007]

However, in a conventional image transmission apparatus for transmitting a difference image, when the movement vector is obtained by the above-described method, the amount of calculation becomes considerably large, and the burden on the surveillance camera increases. So expensive C
If a PU is required or the cost is reduced, there is a problem in that the operation speed becomes slow and it takes a long time to transmit, so that monitoring in real time becomes impossible.

Accordingly, an object of the present invention is to provide an image transmission monitoring device capable of reducing the amount of calculation for obtaining a movement vector and increasing the detection speed even if an inexpensive processing device is used.

[0009]

As means for achieving the above object, an object of the present invention is to provide an image transmission apparatus having the following configuration.

[0010] 1. What is claimed is: 1. An image transmitting apparatus which transmits only an image of an area where a change has occurred by obtaining a difference between a reference image and a current image, wherein a storage unit stores the reference image and the current image, and each pixel of the current image Binarizing means for binarizing by comparing a difference between each pixel of the reference image and the first reference value with each other, and projecting the data binarized by the binarizing means in the axial direction. Projection means for calculating the obtained one-dimensional data to obtain a projection value, and a range in which projection values having a value equal to or greater than a second reference value are continuous from the projection value calculated by the projection means for a predetermined number or more. Difference determining means for determining the difference area by calculating the center of gravity position from the weighted sum of the projection values in the difference area; and the center of gravity supplied from the center of gravity calculation means and the previously obtained center of gravity position. Movement calculation to calculate the amount of movement and the direction of movement of the center of gravity Means for compressing and coding the current image in the difference area determined by the difference determination means, and adding the position information indicating the position of the difference area, the movement amount, and the movement to the compressed current image data. An image transmission apparatus comprising: compression means for adding a direction and outputting; and transmission means for transmitting data supplied from the compression means.

2. 2. The image transmission apparatus according to claim 1, further comprising a transmission determination unit configured to determine whether transmission by the transmission unit is possible based on the moving amount and the moving direction in the difference area.

3. 3. The image transmission device according to claim 1, wherein the image recording unit records the image compressed by the compression unit, and the image recording unit transmits the image to the image recording unit based on the moving amount and the moving direction in the difference area. An image transmission device comprising: a recording determination unit that determines whether or not to record an image.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the image transmission apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the image transmission device of the present invention.

The image transmission apparatus shown in FIG. 1 is a monitoring camera 1 serving as an imaging means, and an A / D converter for A / D converting an image signal picked up by the monitoring camera 1 and outputting RGB image data. 2, a current image frame memory (storage means) 3 which is a frame memory for storing a current image, a reference image updater 4 for controlling reference image update, and a reference image frame memory (storage means) for storing reference images. 5, an image signal converter 6 for converting the RGB signals supplied from the current image frame memory 3 and the reference image frame memory 5 into a luminance signal and a color difference signal and outputting the signals, and respective images of the current image signal and the reference image signal A binarizing unit (binarizing means) 7 for binarizing the data (luminance signal) with a reference value and converting a projection value in the axial direction from the binarized data output from the binarizing unit 7 The desired projection calculation unit (projection means 8, a difference determination unit (difference determination means) 9 for determining the range of the difference from the projection values, the center-of-gravity calculation section (center-of-gravity calculating means) 10 for obtaining the center of gravity from the difference area,
A movement determination unit (movement determination unit) 11 that calculates the amount and direction of movement of the center of gravity position from the previously obtained center of gravity position and the current center of gravity position, and a JPEG compression unit (compression) that JPEG compresses a rectangular area including the difference area. A data transmitting unit (transmitting unit) 13 for adding position information indicating the position of the difference area, a moving amount, and a moving direction to the JPEG image data output from the JPEG compressing unit 12 and transmitting the same to a transmission path; It is composed of

Next, the operation of the image transmission apparatus having such a configuration will be described. An image signal of an image captured by the monitoring camera 1 is converted into RGB image data by the A / D converter 2. The converted RGB image data is stored in the current image frame memory 3, and the same image data is stored as a reference image in the reference image frame memory 5 via the reference image updater 4 at the time of initial activation or reference image update. The current image data in the current image frame memory 3 is sequentially supplied to the image signal converter 6, and at the same time, the reference image data stored in the reference image frame memory 4 is also supplied to the image signal converter 6. The image signal converter 6 converts each of the RGB image data into YUV data (luminance data and color difference data), and outputs the luminance data of each image to the binarization unit 7,
JPEG compression unit 1 for luminance data and color difference data of the current image
Output to 2. The luminance data (sampling data indicating a luminance value) of each image output from the image signal converter 6 is 2
Example of sampling data of a reference image as shown in FIG. 2 (part of one screen is shown).
Or an example of the sampling data of the current image (showing a part of one screen) as shown in FIG.

The binarizing unit 7 receives the luminance data of each pixel supplied as two-dimensional array data, compares the current image data at the same position with the reference image data, and calculates the absolute value of the difference. Then, if the absolute value is larger than the first reference value, data of a new two-dimensional array is set to 1 and otherwise set to 0 and output to the projection calculation unit 8 and the centroid calculation unit 10. Then, the projection operation unit 8 obtains the sum of the data of the same row and the same column for all the columns and all the rows from the received two-dimensional array data, and outputs each to the difference determination unit 9 as a one-dimensional array. FIG. 4 shows an example of the binarized data obtained by the binarizing unit 7, and FIG. 5 shows an example of the result of calculating the projection value by the projection calculating unit 8. here,
The luminance data of the reference image shown in FIG. 2 is compared with the luminance data of the current image shown in FIG. 3, and the result of binarization with the first reference value being 5 is shown as binarized data. The sum of the same row of the binarized data is the vertical axis projection value, and the sum of the same column is the horizontal axis projection value.

The difference judging unit 9 compares the input vertical axis projection value and horizontal axis projection value of the one-dimensional array with the second reference value, and calculates the vertical axis projection value or horizontal axis projection value of the one-dimensional array. Identifies a range in which a larger element is continuous for a predetermined number or more, and combines the range in the vertical axis direction and the range in the horizontal axis direction into one region,
Using this as the difference area, the actual position on the image is calculated,
The position information is output to the center-of-gravity calculation unit 10 and the JPEG compression unit 12. In FIG. 5, for example, the second reference value is 3,
Assuming that the predetermined number is 4, where four or more values of three or more continue are from the fifth row to the ninth row of the vertical axis projection value, and the fourth to ninth columns of the horizontal axis projection value. As a result, it is possible to determine that the range of the rectangle in which the pixel at the position (4, 5) and the pixel at the position (9, 9) of the current image are diagonal pixels is the difference area.

The center-of-gravity calculating section 10 is provided with the binary data from the binarizing section 7 as shown in FIG.
Since the binarized data as shown in (1) is supplied and the data indicating the difference area is supplied from the difference judging unit 9, first, the projection values of the vertical and horizontal axes are calculated for the binarized data in the difference area. I do. Then, the calculated projection values are weighted for each position, the sum is obtained, and 2
The center of gravity is obtained by dividing by the sum of the quantified data, and is output to the movement determining unit 11. FIG. 6 shows a result of recalculating the vertical axis projection value and the horizontal axis projection value for the binarized data in the difference area in the center of gravity calculation unit 10. First, the data on the vertical axis is multiplied by the weight of the data position to obtain the sum, 0 × 1 + 0 ×
2 + 0 × 3 + 0 × 4 + 3 × 5 + 6 × 6 + 6 × 7 + 6 × 8 + 3 × 9 + 0 × 10 = 168, and the sum of the binarized data in the difference area is 3 + 6 + 6 + 6 + 3 = 24 and 16
Dividing 8 gives 7.0, and the center of gravity of the difference area in the vertical axis direction is
You can ask for 7.0. Similarly, when the position of the center of gravity in the horizontal axis direction is calculated as the horizontal axis projection value, it can be obtained as 6.6.
Therefore, (6.6, 7.0) can be determined as the position of the center of gravity of the difference image.

The movement determination unit 11 stores the center of gravity position sent from the previous center of gravity calculation unit 10 and compares the previous center of gravity position with the current center of gravity position to determine the amount of movement of the center of gravity position. JPEG compression unit 1 to determine the moving direction
Output to 2.

The JPEG compression section 12 extracts only the area corresponding to the difference from the position information indicating the difference area input from the difference determination section 9 from the current image data input from the image signal converter 6 and performs JPEG compression. The position information indicating the difference area (information indicating the JPEG-compressed area) and the movement amount and movement direction of the center of gravity supplied from the movement determination section 11 are embedded in the header section of the JPEG data and then output to the data transmission section 12. I do. In order to transmit the input JPEG data to the destination, the data transmission unit 12 performs data conversion into a form suitable for the transmission path and outputs the JPEG data to a transmission path (not shown). In this way, by transmitting only the image in the difference area, it is possible to transmit high-resolution image data with a small amount of data. Further, in addition to the calculation of the difference area, the calculation of the amount of movement of the center of gravity and the direction of movement are also performed from the one-dimensional data obtained by projecting the binarized data. It becomes possible.

The image signal converter 6 outputs only the luminance data to the binarizing unit 7 to detect the difference. However, the difference detection is performed not only with the luminance signal but also with the chrominance signal. Even if it does, and without conversion
Difference detection may be performed for each of the GB data, and the same can be applied to other embodiments described below.

FIG. 7 shows a second embodiment of the image transmission apparatus of the present invention. The image transmission apparatus shown in FIG. 1 includes a transmission determination unit (transmission determination unit) 14 that determines whether transmission by the data transmission unit 13 is possible or not based on the movement amount and the movement direction in the difference area supplied from the movement determination unit 11. This is a configuration different from the first embodiment shown in FIG. Here, the description of the same configuration and the same operation part as those of the first embodiment shown in FIG.
Only different parts centered on the transmission determination unit 14 will be described.

The transmission judging section 14 is supplied with the JPEG compressed image data from the JPEG compressing section 12 and
Supplies the moving amount and moving direction of the difference image. Then, the reference movement amount and the reference movement direction set in advance are compared with the movement amount and the movement direction of the difference image supplied from the movement determination unit 11, and when the conditions match the preset conditions, The JPEG compressed image data is output to the data transmission unit 13.
The EG image data is discarded without being sent to the data transmission unit 13.

In the present embodiment, for example, a difference image is transmitted only when there is a moving object at a predetermined speed or more, or in a situation where a passage whose traveling direction is determined is monitored, a reverse image is used. The setting according to the use condition of the image transmission device can be performed, such as transmitting the difference image only when there is a moving object.

FIG. 8 shows a third embodiment of the image transmission apparatus of the present invention. The image transmission device shown in FIG.
The second embodiment shown in FIG.
An image recording unit (image recording means) 15 for recording a JPEG compressed image compressed by the second method, and a recording determination unit (judgment) for judging whether or not an image can be recorded on the image recording unit 15 based on the moving amount and moving direction in the difference area. (Recording determination means) 16 is added. Here, the second line shown in FIG.
The description of the same configuration and the same operation as in the embodiment is omitted by attaching the same reference numerals, and only different portions will be described.

The recording judging unit 15 is supplied with JPEG image data from the JPEG compressing unit 12, and is supplied with the moving amount and moving direction of the difference image from the moving judging unit 11. And
The predetermined reference movement amount and the reference movement direction are compared with the movement amount and the movement direction of the difference image supplied from the movement determination unit 11, and if the predetermined conditions are met, JPEG compression is performed. The image data is output to the image recording unit 16, and if the conditions are not met, the JPEG image data is discarded without being sent to the image recording unit 16. In the image recording unit 16, the JPE supplied from the recording determination unit 15
The G compressed image data is recorded on a storage medium such as an optical recording medium or a hard disk. The determination of whether or not the recording can be performed by the recording determination unit 15 is determined independently of the determination of whether or not the transmission can be performed by the transmission determination unit 14. Therefore, the image recording to the image recording unit 16 and the data transmission Can be performed individually and independently.

Therefore, in the present embodiment, for example, in a situation where an intersection or the like is being monitored, if a moving object goes straight, neither recording nor transmission is performed, and when a left turn is made, recording is performed but transmission is not performed. Various conditions such as recording and transmitting only when turning right can be set.

[0028]

Since the image transmission apparatus of the present invention has the projection calculating means and the center of gravity calculating means, the moving amount and moving direction of the difference image can be obtained with a small amount of calculation. It is possible to determine a sequential transition.

Further, when the transmission determining means is added, it is possible to set not only the difference generation but also the condition of whether or not to transmit the difference image according to the state of the difference generation.

Further, when the recording determining means and the recording means are added, there is an effect that it is possible to separately set transmission and recording conditions according to the state of occurrence of the difference.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a first embodiment of an image transmission device according to the present invention.

FIG. 2 is an explanatory diagram illustrating an example of reference image data.

FIG. 3 is an explanatory diagram illustrating an example of current image data.

FIG. 4 is an explanatory diagram illustrating an example of binarized data binarized by a binarizing unit;

FIG. 5 is an explanatory diagram illustrating an example of a projection value calculated by a projection calculation unit.

FIG. 6 is an explanatory diagram illustrating an example of a projection value calculated by a center of gravity calculation unit.

FIG. 7 is a configuration diagram showing a second embodiment of the image transmission device of the present invention.

FIG. 8 is a configuration diagram showing a third embodiment of the image transmission device of the present invention.

[Explanation of symbols]

 Reference Signs List 1 surveillance camera (imaging means) 2 A / D converter 3 current image frame memory (storage means) 4 reference image updater 5 reference image frame memory (storage means) 6 image signal converter 7 binarization section (binarization) 8) Projection calculation unit (projection unit) 9 Difference determination unit (difference determination unit) 10 Center of gravity calculation unit (centroid calculation unit) 11 Movement determination unit (movement determination unit) 12 JPEG compression unit (compression unit) 13 Data transmission unit ( (Transmission means) 14 transmission determination section (transmission determination means) 15 recording determination section (recording determination means) 16 image recording section (image recording means)

Continuation of the front page F term (reference) 5C054 AA01 AA05 CA04 CC03 EA01 EA03 EA05 ED17 EF01 EF06 EG10 FC05 FC13 HA18 HA26 5C084 AA04 AA07 AA13 BB31 CC16 CC19 DD12 GG07 GG09 GG11 GG42 GG52 GG52 GG52 GG52 GG52 HA04 9A001 BB03 BB04 EE04 EE05 HH24 HH27 HH28 HH30 HH31 JJ23 JJ24 KK31 KK37 KK42 LL02

Claims (3)

[Claims] 1. An image transmission device for obtaining a difference between a reference image and a current image and transmitting only an image of an area that has changed, comprising: storage means for storing the reference image and the current image; Binarizing means for comparing a difference between each pixel of the current image with each pixel of the reference image corresponding to the first reference value and binarizing the data, and data binarized by the binarizing means; Projecting means for calculating one-dimensional data obtained by projecting in the axial direction to obtain a projection value, and projecting values having a value equal to or more than a second reference value from the projection value calculated by the projecting means are continuous for a predetermined number or more. Difference determining means for determining a difference area by determining a range in which the difference is calculated; centroid calculating means for calculating a centroid position from a weighted sum of projection values in the differential area; and a centroid position supplied from the centroid calculating means. The amount and direction of movement of the center of gravity from the center of gravity A movement determining means for calculating; and a compression encoding of the current image in the difference area determined by the difference determination means, and position information indicating a position of the difference area in the compressed current image data and the movement. An image transmission apparatus, comprising: compression means for adding and outputting an amount and the moving direction; and transmission means for transmitting data supplied from the compression means. 2. The image transmission apparatus according to claim 1, wherein
An image transmission apparatus comprising: a transmission determination unit that determines whether transmission by the transmission unit is possible based on the movement amount and the movement direction in the difference area. 3. The image transmitting apparatus according to claim 1, wherein said image recording means for recording the image compressed by said compression means, and said moving amount and said moving direction in said difference area. An image transmission device comprising: a recording determination unit configured to determine whether an image can be recorded on an image recording unit.