KR20070045428A - Unmanned surveillance system - Google Patents

Abstract

The present invention relates to an unmanned surveillance system or a security system. In particular, when a surveillance camera tracks a subject by a motion vector corresponding to a variation of an acquired image, and stores image data of a surveillance region in a wide variety of storage media. The present invention relates to an unmanned surveillance system for reducing data storage capacity and monitoring a real subject by storing and reproducing image data in response to variations in tracking contents as described above.

Description

Unmanned a monitor a system

1 is an exemplary block diagram of an unmanned surveillance system according to the present invention.

2 is an embodiment for implementing the unmanned surveillance system shown in FIG.

3 is yet another embodiment for implementing the unmanned surveillance system shown in FIG.

The present invention relates to an unmanned surveillance system or a security system. In particular, when a surveillance camera tracks a subject by a motion vector corresponding to a variation of an acquired image, and stores image data of a surveillance region in a wide variety of storage media. The present invention relates to an unmanned surveillance system for reducing data storage capacity and monitoring a real subject by storing and reproducing image data in response to variations in tracking contents as described above.

In general, an unmanned surveillance system or security system is used to photograph a place where security and security are required for security and security of various buildings such as banks, government offices, etc. and further to protect personal property and life. It is a system that can conveniently secure the security of the place without the expense.

The most distinctive feature of these systems is that they constantly monitor certain areas to be monitored or monitored by surveillance cameras, and read and store the images or alert them by determining whether an emergency has occurred. .

These surveillance cameras can be installed at the entrance of the doorway to check the presence and absence of a person without opening the door, to close cameras at banks, large sales offices, prisons, businesses, public institutions, etc. Its applications and functions are being expanded to include traffic cameras for crackdowns, parking violations, and traffic control, especially with the acceleration of technological developments related to automatic control, image recognition, and three-dimensional computer vision. An intelligent surveillance camera capable of automatically tracking and capturing an aperiodically appearing subject, recognizing the subject, providing information about the subject, and even having control over the subject is expected.

Surveillance cameras, as their name implies, are only classified for surveillance purposes, and in broad terms, the imaging principle and basic function is to convert the optical image into an electrical signal form through photoelectric conversion, As it is included in the category of the photoelectric conversion camera for imaging, it operates on the same imaging principle as a typical photoelectric conversion camera, a video camera and a broadcast RGB camera, and shares many functions.

Models with fixed angles of view and mounting positions, and variable angles of view but with fixed positions, models with fixed angles of view moving along a preset movement path, and users' demand for performance and functionality is gradually increasing. With the increase, small size, light weight, low power consumption, high performance and multifunctionality are pursued.

That is, the Auto White Balance (AWB) function that adjusts the color balance by adjusting the color temperature of the image to improve the functionality of the surveillance camera and the Auto Focusing which automatically focuses the camera. In addition to adopting the automation function represented by the AF) function, and the like, in particular, the functions that give adaptability to the change in the shooting conditions caused by the change in the weather, the sun, and the dynamic change of the monitoring object are used. Selectively adopt according to the use.

Related patent applications include Korean Patent Application No. 90-20717 Mobile Surveillance Camera Device, Korean Patent Application No. 90-18774 Automatic Tracking Device for Shooting System, Korean Patent Application No. 91-11623 Automatic Camera Tracking Device Etc. can be mentioned.

In addition to the development of the control technology of the surveillance camera as described above, the technology for storing the captured image has also been further developed by the development of data processing technology, the known video compression system is the two basic forms of compression processing Include spatial and temporary processing methods.

The above-described spatial processing method compresses information by transforming image elements within a specific frame of a video signal according to a compression algorithm, thereby reducing the amount of information required for reproduction of a frame. In contrast, ad hoc processing considers how information changes over time.

Therefore, the amount of information required for reproduction of the frame is reduced in consideration of the change of the image occurring from frame to frame. These changes are reflected in the generated motion vector and transmitted instead of the actual content of the video frame. A description of the implementation of spatial and ad hoc processing can be found in the MPEG Compression Recommendation ISO / IEC 1172-2, referred to herein as the MPEG standard.

The MPEG standard is one of several known video processing standards.

Thus, the conventional MPEG encoder allows the degree of spatial processing to be changed to conserve memory by adjusting the quantization of information of a particular frame. Such an encoder has the function of detecting the movement of the picture from frame to frame and adjusting the degree of temporary processing (ie adjusting the motion vector).

Within the screen monitored by the video camera, the movement may be due to the movement of the subject (eg, a person passing the camera's field of view) or due to the camera (ie, panning, tilting, zooming or focusing the camera). May occur as a result of movement. When the picture is moving, the motion information must be extracted to generate a motion vector.

Prior art systems that perform ad hoc processing to convey motion information (eg, systems using MPEG-type compression) require relatively large memory space and computational power.

In order to store the image data acquired as described above, the storage data must have a considerable storage capacity. Therefore, the storage medium does not specify any one storage medium and can selectively use a storage medium that a user wants to use or needs. In addition, there is a need to develop a technology of allowing a camera to track a subject and storing and recording data generated in response to the tracking method in a corresponding storage medium.

An object of the present invention for overcoming the problems of the prior art as described above relates to an unmanned surveillance system or a security system, in particular, tracking a subject by a motion vector corresponding to the variation of the image obtained by the surveillance camera, When storing the image data of the surveillance area in the storage medium, the image data is stored in response to the variation of the tracking contents as described above, and when combined, the image data is combined and reproduced to reduce the storage capacity of the data and monitor the actual subject. It is to provide an unmanned surveillance system to make it possible.

Features of the unmanned surveillance system according to the present invention for achieving the above object, including a lens, to generate a video signal comprising a plurality of video images by imaging the optical image as an electrical video signal through photoelectric conversion A camera; An image signal processor for generating a motion vector by detecting a difference image signal between a previous image signal delayed for a predetermined screen unit time and the image signal inputted at the present time by delaying the image signal acquired through the camera; Compression means for generating a compressed video signal by achieving a degree of compression processing on the video signal based on an initial video screen acquired through the camera and a difference video signal detected by the video signal processor under arbitrary conditions; Camera driving control means for tracking the subject by driving the camera based on the motion vector generated by the image signal processor; And a processor for outputting, to the compression means, an instruction for changing the degree of compression processing in response to the adjustment instruction signal.

An additional feature of the unmanned surveillance system according to the present invention for achieving the above object is a DVD-RW player, CD-RW player, VTR or VCR as a storage medium for storing the video compressed data generated by the compression means And storage media through image storage means.

Another additional feature of the unmanned surveillance system according to the present invention for achieving the above object is that the storage means for storing the video signal generated through the compression means accesses the stored data under any conditions and And reconstructing means for reconstructing the video image on the basis of the initial screen and the subsequent difference image signal.

The above object and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention described below with reference to the accompanying drawings by those skilled in the art.

First, the technical idea applied to the present invention will be briefly described, and the present invention provides a method for recognizing the known information on the motion of a video picture caused by the movement caused by a camera in order to reduce the computational and memory overhead required for the compression of the video data. Focus on use.

That is, the present invention is to reduce the consumption of the storage medium by storing the image taken on the basis of the generated data while the camera tracks the subject, and restores it according to reverse processing in the future restoration.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

FIG. 1 is a block diagram illustrating an entire system according to the present invention, which will be described with reference to FIGS. 2 and 3.

FIG. 2 is a diagram illustrating a video camera device 1 not shown in FIG. 1 and an image processing central processing unit (not provided with reference numerals). The A / D color space converter 20 and the fan are shown. A pan-tilt-zoom video camera 10 having a tilt-zoom ('PTZ') unit 18, a control panel 30 having a user input 32, and a control interpreter 40 (related memory Has a properly programmed microprocessor) and a compression unit 50.

The camera 10 generates a video signal 19 (consisting of a video image comprising an image element) which is supplied to the color space converter 20, which is output at the output 52 to the digital chrominance and luminance signal Cr. , Cb and Y).

The camera 10 also has a zoom lens 12 having a focus control mechanism 14 and a zoom control mechanism 16.

The PTZ mechanism 18 allows the camera 10 to be panned, tilted, and zoomed by a command input from the control panel 30. The control panel 30 and control interpreter 40 may be included in a unit based on a single microprocessor, preferably available from the 'Touch-tracker' of Sernsormatic Electronics Corp., Deerfield Beach, Florida.

In addition, the camera 10 together with the combined lens and PTZ unit 18 and color space converter 20 is preferably an integrally self-contained 'dome' available as a 'Speed-Dome' from Sernsormatic Electronics Corp. Included in

The compression unit 50 is a conventional video compression unit comprising hardware and software that implements a compression algorithm, preferably the known MPEG system described in the MPEG standard. The MPEG standard describes a system that achieves a degree of compression processing (including spatial and ad hoc processing).

A system may be used in which the degree of compression processing may vary. For example, a known system having a compression filter (with a predetermined filter length and shape and coefficients) in which the degree of spatial compression is varied by adjusting the compression filter length and adjusting the compression filter coefficients and the compression filter type can be used and this The system may be considered equivalent to the compression unit 50. Since video compression hardware and software are known to those skilled in the art, only those aspects which are closely related to the present invention will be described.

In addition, the compression unit 50 has an input 53 connected to the output terminal 52 of the color space converter 20 which receives the digitized chrominance signals Cr, Cb and the luminance signal Y. At the output 54 it has an input 55 which receives the motion vector calculated by the control interpreter 40.

The generation and purpose of these motion vectors are described below. The input 57 of the compression unit 50 receives a command for the degree of spatial compression processing from the output 56 of the control interpreter 40, details are described below. The compression unit 50 has an output 58 for outputting a compressed video signal for transmission over a communication channel.

The basic components of the preferred compression unit 50 are subtractor 60, discrete cosine transform unit 62, quantizer 64, variable length coder 66, de-quantizer 68, inverse discrete cosine transform unit. 70, the summation point 72, and the image storage predictor 74. FIG.

The quantizer 64 quantizes the discrete cosine transformed signal supplied by the discrete cosine transform unit 62. The extent to which quantizer 64 achieves spatial compression processing for the supplied signal is variable. In quantization achievement results, quantizer 64 has at least two quantization matrices, each of which results in a different degree of spatial compression processing.

Writing a variable to register 65 via input 57 causes one of the quantization matrix notes to be selected. These components are known to those skilled in the art and are all described in detail in the MPEG manual.

As noted above, other compression systems and the MPEG standard include two modes, spatial and temporary compression processing. In the spatial compression processing mode, the compression unit 50 compresses the information in the video frame generated by the video camera 10. Each video frame carries an image made up of large picture elements. In the temporary compression processing mode, a motion vector is generated to account for the change of the picture from one frame to another. The motion vector thus represents an indication of the motion of the image carried by the video frame.

When the camera 10 is stationary, the frame difference from the frame of the video signal generated by the camera 10 is less than when the camera 10 is panning, tilting, zooming or focusing. Moreover, the human eye can better distinguish the image details when the camera 10 is stationary than when the camera 10 is moving. Therefore, the compression operation should be able to convey more image details within each frame when the camera 10 is stationary than when the camera 10 moves.

That is, when the camera 10 is stationary, the degree of spatial compression processing must be low. In the case of the preferred processing system described herein, this corresponds to a low degree of quantization.

When the camera 10 is moving, zooming or focusing, the compression operation must convey more information as the picture changes, so that the signal is reproduced correctly. This requires more bandwidth than when the camera 10 is stationary. An increase in the degree of spatial compression processing (ie, an increase in spatial quantization) removes bandwidth limitations for temporary compression (ie, generation of motion vectors) in response to panning, tilting, zooming, or focusing.

However, this results in less detail when the compressed signal is reproduced. Nevertheless, the human eye is an acceptable solution because it is less sensitive to moving objects than stationary objects.

When the camera 10 is stationary, the lens 12 is focused and the lens 12 is not zoomed, and the control interpreter 40 does not perform a temporary compression process (i.e. does not produce a motion vector). The spatial compression process is low. That is, a quantization matrix that provides low quantization is selected by writing the appropriate value in register 65. This results in an indication of the level of detail about the transmission of the compressed signal at the output 58.

The video signal at the output 52 supplied to the compression unit 50 to the input 53 is compressed according to the MPEG algorithm using the spatial compression processing degree set by the control interpreter 40 and compressed at the output 58. It can be used as a video signal. This signal is passed by the multiplexer 80 to the output 82 for transmission over a communication channel or for transmission to a storage device.

The control panel 30, the control interpreter 40 and the PTZ unit 18 form a camera control system. When the user instructs the camera to pan, tilt, zoom, or focus on user input, the control panel 30 calculates a control signal at the output terminal 31. It is supplied to the control interpreter 40 at the input 41. In response, the control interpreter 40 generates at the output 42 the adjustment instruction signal supplied to the input 43 of the PTZ unit 18 for the camera to pan, tilt, zoom or focus.

In response to the adjustment indication signal, the control interpreter 40 generates a series of motion vectors. The motion vector describes how the image generated by the camera 10 is changed by a command received from the user. The motion vector is output in the format indicated by the MPEG standard, to achieve a temporary compression process. The motion vector is stored in a lookup table in the memory of the control interpreter 40.

Thus, for any particular degree of panning, tilting, zooming or focusing, there is a specific set of motion vectors in the lookup table. The vectors indicating combined panning, tilting, zooming or focusing are obtained by multiplying each vector associated with a particular degree of panning, tilting, zooming or focusing with respect to each other. The motion vector is supplied to the multiplexer 80 and multiplexed with the compressed signal calculated as a result of spatial compression.

When the camera control system causes the camera 10 to be adjusted (panning, tilting, zooming or focusing), the control interpreter 40 outputs a command to the compression unit to increase the degree of spatial compression. In a preferred embodiment, control interpreter 40 selects quantizer 64 to select a quantization matrix that yields a high degree of spatial compression processing to adjust its quantization to a high level by having an appropriate value written to register 65. Command

As panning, tilting, zooming or focusing increases or decreases, the control interpreter 40 outputs a command to the compression unit 40 to reduce or increase the degree of spatial compression processing at an appropriate rate. Thus, when the camera is moved or zoomed or focused relative to its periphery, the compression operation is subject to attention on the frame-to-frame change (temporary compression process) rather than the details of each frame (spatial compression process). Puts.

When panning, tilting, zooming or focusing is stopped, control interpreter 40 stops calculating motion vectors. This also allows the degree of spatial compression to be adjusted to an appropriate low level.

The described system also allows the degree of compression processing to vary depending on the video camera. This allows a tradeoff between spatial and temporal processing based on prior knowledge of whether the camera is panning, tilting, zooming or focusing.

This system has been described with reference to a system in which the degree of spatial compression processing is changed by adjusting the quantization of the MPEG-type compression processing system.

In addition, the present invention may be implemented differently from the case shown in FIG. 2, which is the same as the example shown in FIG. 3.

3 is an overall block diagram showing an embodiment of an apparatus for automatically detecting a subject of a surveillance camera according to the present invention, which includes a lens unit 100 for condensing an optical image and an optical image incident through the lens unit 100. The image sensor 110 and the output signal of the image sensor 110 to capture the photoelectric conversion through the photoelectric conversion, automatic gain control (AGC), gamma correction (Correlation Double Sampling; CDS), etc. The difference image signal is obtained between the preprocessor 120 which performs the same preprocessing, the previous image signal stored in the field memory of the image signal output from the preprocessor 120 and the image signal input at the present time point, and the difference image. A subject detection unit 200 for detecting a region having a relatively large pixel value as a target subject region that causes an instant data change, and a contrast ratio based on the target subject region; A focus control unit 300 that performs focus adjustment so that the example information increases, a subject zoom-in unit 500 that zooms in to enlarge and capture the target subject area after performing focus adjustment, and the subject detection unit 200. Detects the target subject area from the subject detecting unit 200 and receives the information on the target subject area from the subject detecting unit 200 to perform focus adjustment and zoom-in to zoom in and capture the subject. The monitoring imaging control unit 400 controls the subject zoom-in unit 500.

Here, the subject detecting unit 200 receives a video signal output from the preprocessor 120 and stores it for one field to generate a previous video signal, and inputs the previous image signal at the present time. After subtracting the video signal to be subtracted, there is a difference image calculator 220 for calculating the difference image signal by taking an absolute value, and a target subject causing an instantaneous data change in a region where the pixel value of the difference image signal is relatively large And a subject region setting unit 230 for setting the target subject region.

The focus adjusting unit 300 receives the image signal and outputs a band pass filtered band signal by band pass filtering, and a focus adjusting lens moving unit which is a focus adjusting lens moving unit for focus adjustment. The focus control motor driver 330 for driving the motor, and the focus control controller 320 for controlling the focus control motor driver 330 to increase the gain of the band signal.

In this case, the band filtering unit 310 may include a low pass filtering unit 311 for low-pass filtering the image signal with respect to a first reference frequency, and a low frequency filtering unit 311 with a relatively smaller output than the first reference frequency. A first high pass filtering unit 312 for outputting a first band signal, which is a signal obtained by performing high pass filtering on a second reference frequency and band-filtering the video signal, and an output of the low frequency filtering unit 311 from a first reference frequency And a second high pass filtering unit 313 for performing a high pass filtering on a third reference frequency that is relatively small and larger than a second reference frequency to output a second band signal which is a band-filtered signal. Preferably, the frequency is 200 MHz, the second reference frequency is 300 KHz, and the third reference frequency is 850 KHz.

In addition, the focus control controller 320 controls the focus control motor driver 330 to increase the gain of the first band signal, thereby determining a moving direction of the focus control lens shift motor 321. And a second focusing control unit 322 that performs forward focusing by controlling the focusing motor driver 330 to increase the gain of the second band signal.

The subject zoom-in unit 500 may include a zoom motor driving unit 520 for driving a zoom lens moving motor (not shown), which is a zoom lens moving unit for zoom-in, and when the focus adjusting unit 200 finishes focusing, The zoom-in controller 510 zooms in to enlarge and capture a target subject area.

Accordingly, in implementing the technique of FIG. 1 according to the present invention, when using the technique illustrated in FIG. 2, the storage capacity may be reduced by storing a signal referred to by reference numeral 82. In the case of using the technique illustrated in FIG. 2, the image output from the difference image calculating unit denoted by reference numeral 220 is stored.

While the invention has been shown and described in connection with specific embodiments thereof, it is well known in the art that various modifications and changes can be made without departing from the spirit and scope of the invention as indicated by the claims. Anyone who owns it can easily find out.

When the unmanned surveillance system according to the present invention as described above is provided, the surveillance camera tracks a subject by a motion vector corresponding to the variation of the acquired image, and stores the image data of the surveillance region in a wide variety of storage media. In response to the above-described variation of the tracking content, the image data is stored and reproduced at the time of reproduction, thereby reducing the storage capacity of the data and monitoring the actual subject.

Claims (1)

A camera, including a lens, for capturing an optical image into an electrical image signal through photoelectric conversion to generate a video signal including a plurality of video images; Motion vector is generated by detecting the difference image signal between the previous image signal delayed for the predetermined screen unit time and the image signal inputted at the present time by acquiring the camera driving control signal of the user. An image signal processor configured to generate a motion vector according to the input signal; A processor for outputting a signal for increasing the degree of compression processing if it is determined that the camera is driven by the motion vector generated by the image signal processing unit and a signal for lowering the degree of compression processing if it is determined that it is not driven; Compression means for achieving a degree of compression processing in accordance with the signal output from the processor; Camera driving control means for tracking the subject by driving the camera based on the motion vector generated by the image signal processor; Storage means for storing the image compressed data generated by the compression means; And And reconstruction means for restoring a video image based on an arbitrary initial screen and a subsequent difference image signal by accessing data stored under an arbitrary condition in the storage means for storing the video signal generated through the compression means. Unmanned surveillance system.

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