KR100376753B1 - Method for output image of video monitoring system - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for displaying and outputting a good image despite a difference in scanning method between an image photographing apparatus and a display apparatus. Outputting to the display device, the horizontal / vertical reduction ratio being different for each channel image data of the digitally interlaced scanning method; Storing the scaled image data in a memory for configuring a screen; And outputting and displaying the stored one screen image data to the sequential scanning type image display device.

Description

Video output method of video surveillance system {METHOD FOR OUTPUT IMAGE OF VIDEO MONITORING SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video surveillance system, and more particularly, to a method for displaying and outputting a good image despite a difference in scanning method between an image photographing apparatus and a display apparatus.

In general, a video surveillance system processes a plurality of images input from one or more video cameras and displays them on a monitor in a split screen. The video signal photographed and input from the video camera is generally captured by the interlaced scan method, and the video signal captured by the interlaced scan method is output to a television which is a display device through horizontal and vertical scalers having the same ratio.

Recently, in order to store a larger amount of image data, the spread of a personal computer (PC) based digital video recorder (DVR) has been rapidly made. However, since the monitor, which is a video display device of such a video surveillance system, adopts a sequential scanning method, problems such as deterioration of image quality and resolution deterioration occur. Referring to this in more detail with reference to Figure 1,

First, as illustrated in FIG. 1, video signals captured by four video cameras in the interlaced scanning method are divided into four screens as shown in FIG. 1B by horizontal / vertical scalers having the same ratio. However, when the image signal photographed by the interlaced scanning method is simply displayed on the display device of the sequential scanning method as shown in (d) as shown in (c) of FIG. 1, the image as shown in (e) is displayed as a result. Since the oval image is reduced to 1/2, you will see the distorted image.

In order to solve this problem, as shown in (f) of FIG. 1, an odd-numbered and even-numbered field is sequentially mixed as shown in FIG. The aspect ratio of the output signal becomes the same so that a normal screen can be output. However, if such a screen is not a still image but a video, a 1/60 second time difference occurs between the odd field and the even field, so that the distorted video is displayed as shown in (h), and the resolution is degraded as well.

On the other hand, the "screen split display using the scanning line conversion function" (filed application number 10-1998-52991), which was previously filed and patented by the Republic of Korea Patent Office. This prior art includes two video decoders, two memories, and two video encoders for scanning line conversion, and a TV monitor and a computer monitor are connected to each encoder output. The above patent invention records a video signal in a memory in front of a video encoder connected to a computer monitor, reads out twice as fast as the recording speed, and converts scan lines.

However, since the above-described prior art has to pass through the video decoder, the video encoder, the video decoder, the video encoder in order to output the interlaced video signal input from the video camera to the computer monitor of the progressive scan method, Signal degradation inevitably occurs. In addition, since a video signal must be read twice as fast as the memory write speed, a clock for memory control is required. This has the disadvantage that the design of the memory control means is complicated.

Accordingly, an object of the present invention is to provide an image output method of an image surveillance system capable of displaying an optimal image without deterioration of image quality despite a difference in scanning method between an image signal input device and a display device.

It is still another object of the present invention to provide an image output method capable of displaying an image obtained by reducing an interlaced scanning video signal captured by one or more cameras at a different ratio with respect to a vertical direction and a horizontal direction on an interlaced display device. In providing.

1 is an exemplary view of a processing video signal display screen for explaining a general video output method.

2 is a block diagram of a video surveillance system according to an embodiment of the present invention.

3 is an exemplary view of a processed video signal display screen for explaining a video output method according to an embodiment of the present invention.

Image output method of the video surveillance system according to an embodiment of the present invention for achieving the above object;

In outputting the interlaced channel video signal photographed by one or more cameras to the progressive scan video display device,

Scaling the horizontal / vertical reduction ratio differently for each channel image data of the digitally converted interlaced scanning method;

Storing the scaled image data in a memory for configuring a screen;

And outputting and displaying the stored one screen image data to the sequential scanning type image display device.

In addition, the present invention is characterized in that the reduction ratio in the horizontal / vertical direction is 1/2: 1 for each channel image data.

That is, the present invention reduces the size of 1/2 screen only in the horizontal direction by using the fact that the interval between the upper and lower lines in the interlaced scanning method is twice as large as the interval between the upper and lower lines in the sequential scanning method. Despite the difference in scanning method, it is possible to display an optimal image without deterioration of image quality.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

2 is a block diagram of a video surveillance system according to an embodiment of the present invention.

Referring to FIG. 2, first, the A / D converters 20a to 20c convert analog video signals input from the corresponding video cameras 10a to 10c into digital video data and output them. Such A / D converters 20a to 20c exist in the same number as the installed video cameras, and the number of video cameras is installed and operated in plurality, such as four or eight, depending on the surveillance area.

The image input controllers 30a to 30c extend the digital image data output from the A / D converters 10a to 10c, and separately control and control the synchronization signal to output the data to the memory controller 50. The image input control units 30a to 30c also match the number of A / D converters 20a to 20c.

The horizontal / vertical scalers 40a to 40c serve to reduce (or enlarge) the horizontal and vertical directions to store the image data output from each of the image input controllers 30a to 30c as split screens. Such horizontal / vertical scalers 40a to 40c reduce the screen by interpolating between adjacent image data according to the screen reduction ratio as already known. In addition, the horizontal / vertical scalers 40a to 40c may reduce (or enlarge) the screen ratio to the horizontal and vertical directions of the horizontal / vertical scalers 40a to 40c according to how many split screens are displayed on the image display unit 90. May vary, and the screen reduction ratio in the horizontal / vertical direction may vary according to the scanning method of the image display unit 90. This will be described in more detail in the operation description of the present invention. These horizontal and vertical scalers 40a to 40c also match the number of video cameras 10a to 10c.

The memory controller 50 records the image reduced (or enlarged) image data output from each of the horizontal and vertical scalers 40a to 40c at the address of the memory 60 designated for each channel. The recorded image data is read and output so that the recorded image data can be displayed in real time. The memory controller 50 receives the horizontal and vertical synchronous signals output from the image input controllers 30a to 30c, and configures a screen of n frames divided by n. For example, in the case of configuring a 4-split screen, the memory controller 50 configures a scaled 4-split screen by checking whether the vertical synchronization signal is completed from each channel based on one of the four channels. can do.

The memory 60 temporarily stores image data of one frame that is accessed and controlled by the memory controller 50 and output from the video camera.

The image output controller 70 synthesizes and outputs additional information (time, channel information, etc.) on image data of one screen output from the memory controller 50. The image data output from the image output controller 70 is converted into an analog image signal through the D / A converter 80 and output to the image display unit 90. The image display unit 90 may be a display device employing interlaced scanning or a display device employing progressive scanning.

In the video surveillance system having the above-described configuration, when the video cameras 10a to 10c employ the interlaced scanning method and the video display unit 90 adopts the progressive scanning method, the method for outputting an image without deterioration of image quality. This will be described. In the following description, a case in which a four-split screen is configured and displayed as one frame as shown in FIG. 3 will be described as an example.

3 is an exemplary view of a processed video signal display screen for explaining an image output method according to an exemplary embodiment of the present invention.

First, video signals of each channel photographed by four video cameras 1, 2, 3, and 4 are converted into digital image data through corresponding A / D converters 20a, 20b,... The digital image data is inputted to the horizontal / vertical scalers 40a, 40b, .. while the horizontal / vertical synchronous signals are separated from the image input controllers 30a, 30b, .., and extended to digital data for post-processing. do. The horizontal / vertical scalers 40a, 40b, .., which are connected to the rear ends of the image input controllers 30a, 30b, .. respectively, perform 1/2 scaling in the horizontal direction and do not perform scaling in the vertical direction. If designed, the 640 × 240 image signal captured by the interlaced scanning method is reduced to 320 × 240 size and stored in the memory 60 under the control of the memory controller 50.

As illustrated in (b) of FIG. 3, an example of the 4-division video data reduced by 1/2 only in the horizontal direction is illustrated. For reference, FIG. 3A illustrates an image signal of 640 × 240 size photographed by interlaced scanning. As shown in (b) of FIG. 3, since the 4-split video signal having a size of 640x480 is a screen made of a signal input from a video signal input device employing an interlaced scanning method, the video of each divided screen is vertical. It has a distorted image in the direction. The vertical line spacing in the image display apparatus employing the interlaced scanning method is about twice as large as the vertical line spacing in the image display apparatus employing the progressive scanning method. Therefore, if the video signal captured by the interlaced scanning method is half-scaled only in the horizontal direction to form a 4-split screen, the screen as shown in FIG. 3 (b) is displayed. Due to the difference in human spacing, a normal picture such as half scaled vertically is displayed. 3C shows an example of the 4-split display screen in this case.

Therefore, if the video signal photographed by the interlaced scanning method is scaled 1/2 in the horizontal direction and configured as a 4-split screen and output to the sequential scanning type image display device, as shown in FIG. The normal screen is not deteriorated.

On the other hand, when outputting a video signal captured by the interlaced scanning method to an image display device employing the interlaced scanning method, it is displayed on the odd-numbered line in the 4-split screen (FIG. If the corresponding image data is output as the image data of the odd field, and the image data corresponding to the even line is output as the image data of the even field, the screen of the two fields as shown in (d) of FIG. 3 is interlaced. As indicated by, the watcher can see the normal screen without any disturbance. Conversely, image data corresponding to odd lines may be output as image data of even fields, and image data corresponding to even lines may be output as image data of odd fields.

As described above, it will be apparent that the control of reading and outputting odd lines or even lines from the split screen image data stored in the frame memory 60 is performed by the memory controller according to the image signal output device.

In the above example, the 4-split screen has been described as an example, but the same applies to the case of the 9-split and 16-split screen display.

For example, suppose that the 9-split screen is configured to be displayed as one screen, and the horizontal / vertical scalers 40a to 40c perform 3: 1 scaling in the horizontal direction to convert the horizontal size of one channel image to 214 pixels. If the image is reduced and the vertical size of one channel image is reduced to 160 pixels by performing 3: 2 scaling on the vertical direction, a 9-division screen having a size of 640 × 480 is formed. When the 9-split screen is displayed as it is on the image display device employing the sequential scanning method, a normal screen is displayed. In addition, when displaying on an image display device employing interlaced scanning, an odd line is displayed in an odd field and an even line is displayed in an even field, and a normal screen is displayed as in a 4-split screen. Can be.

In addition, if the 16-split screen is configured to be displayed as one screen, 4: 1 scaling in horizontal direction (that is, interpolation of four pixels in the horizontal direction to make one pixel) is performed on the image signal photographed by interlaced scanning. If you execute 2: 1 scaling in the vertical direction, a 16-split screen having a size of 640 × 480 is created. When one 16-split screen is output to a video display device employing a sequential scan method or interlaced scan method in the same manner as a 4-split screen, a normal screen may be displayed.

As another embodiment of the present invention, the image signal photographed by using the sequential scanning method may be output to the image display apparatus employing the interlaced scanning method. In this case, the apparatus for photographing the image using the sequential scanning method may be a PC camera, and the screen size in this case corresponds to a size of 640 × 480. When the 640 × 480 size image is output to the interlaced image display device having the 640 × 240 size, the image is simply stored in the frame memory 60 without scaling in the horizontal and vertical directions (scaler bypass). In the video data, the data of the odd line may be output in the odd field, and the data of the even line may be output in the even field. In this case, the aspect ratio of the input signal and the aspect ratio of the display device can remain the same.

Accordingly, the present invention can display the input image as a normal image screen without deterioration and disturbance of image quality even if the input device and the display device of the video signal adopt different scanning methods. A normal screen can be displayed by keeping the aspect ratio of the display device the same.

As described above, the present invention utilizes the fact that the interval between the upper and lower lines in the interlaced scanning method is twice as large as the interval between the upper and lower lines in the sequential scanning method. There is an advantage that can display the optimal image without deterioration.

In the present invention, even when the interlaced scanning video signal is displayed and output in the interlaced scanning method, the present invention can display the same as the original video ratio, thereby displaying a clear image without deterioration of the vertical resolution and deterioration of image quality. It works.

On the other hand, the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be defined only by the appended claims.

Claims (12)

In the video output method of the video surveillance system for screen-split display and output the one or more channel video signal photographed by the interlaced scan method to the video display device of the progressive scan method, Converting at least one channel video signal into digital channel video data; Scaling each of the digitally converted channel image data according to the number of screen divisions, and scaling down the screen by scaling the horizontal / vertical reduction ratio differently; Storing one screen image by storing each channel image data of which the screen is reduced at a designated address of the memory; And outputting the completed screen image data to the sequential scanning type image display device and displaying the screen image data. The image output method of claim 1, wherein each channel image data that is digitally converted is 2: 1 scaling in a horizontal direction and bypassed without scaling in a vertical direction to reduce each channel image data. The image output method of claim 1, wherein each channel image data is reduced by performing 3: 1 scaling in a horizontal direction and 3: 2 scaling in a vertical direction with respect to each of the digitally converted channel image data. The image output method of claim 1, wherein 4: 1 scaling is performed in the horizontal direction and 2: 1 scaling is performed in the vertical direction with respect to each of the digitally converted channel image data. In the video output method of the video surveillance system for screen-divided display the one or more channel video signal photographed by interlaced scanning method to the interlaced video display device, Converting at least one channel video signal into digital channel video data; Scaling each of the digitally converted channel image data according to the number of screen divisions, and scaling down the screen by scaling the horizontal / vertical reduction ratio differently; Storing one screen image by storing each channel image data of which the screen is reduced at a designated address of the memory; And displaying the image data of the even lines among the stored one screen image data as the data of the even fields and outputting the image data of the odd lines as the image data of the odd fields. The image output method according to claim 5, wherein the channel image data is reduced by performing a 2: 1 scaling in the horizontal direction on each of the digitally converted channel image data and bypassing without scaling in the vertical direction. The image output method of claim 5, wherein each channel image data is reduced by performing 3: 1 scaling in a horizontal direction and 3: 2 scaling in a vertical direction with respect to each of the digitally converted channel image data. . The image output method of claim 5, wherein 4: 1 scaling is performed in the horizontal direction and 2: 1 scaling in the vertical direction is performed on each of the digitally converted channel image data. In the video output method of the video surveillance system for screen-divided display the one or more channel video signal photographed by interlaced scanning method to the interlaced video display device, Converting at least one channel video signal into digital channel video data; Scaling each of the digitally converted channel image data according to the number of screen divisions, and scaling down the screen by scaling the horizontal / vertical reduction ratio differently; Storing one screen image by storing each channel image data of which the screen is reduced at a designated address of the memory; And outputting and displaying the even-numbered line image data as odd field data and the odd-line image data as even field image data among the stored one-screen image data. 10. The image output method of claim 9, wherein each channel image data is reduced by performing 2: 1 scaling in the horizontal direction and bypassing without scaling in the vertical direction for each of the digitally converted channel image data. In the video output method of the video surveillance system for screen-splitting and outputting one or more channel video signal photographed in a sequential scan method to the interlaced video display device, Converting at least one channel video signal into digital channel video data; Storing each digitally converted channel image data at a designated address of the memory to construct a screen image; And outputting and displaying the even-numbered line image data as odd field data and the odd-line image data as even field image data among the stored one-screen image data. In the video output method of the video surveillance system for screen-splitting and outputting one or more channel video signal photographed in a sequential scan method to the interlaced video display device, Converting at least one channel video signal into digital channel video data; Storing each digitally converted channel image data at a designated address of the memory to construct a screen image; And displaying the image data of the even lines among the stored one screen image data as the data of the even fields and outputting the image data of the odd lines as the image data of the odd fields.