KR100442518B1 - The Method and System for capture of the Multi-channel Image Signal - Google Patents

Abstract

PURPOSE: A multi-channel image signal capturing method and system is provided to extract synchronizing signals of image signals according to channels to decide an optimum capture sequence, and to capture the multi-channel image signals by the capture sequence, thereby increasing the number of captured frames per second. CONSTITUTION: A multiplexer(310) receives a plurality of image signals from a plurality of channels, and selectively outputs the plurality of image signals. An image synchronizing signal separator(320) extracts synchronizing signals from the plurality of image signals. A synchronizing signal storage(330) stores according to channels the relative start time of the synchronizing signals corresponding to each channel and the cycle of the synchronizing signals corresponding to each channel in association with the relative start time, on the basis of a synchronizing signal of one of the plurality of image signals. A capture sequence decider(340) decides the capture sequence of the plurality of image signals, based on the relative start time and the cycle. An image capture unit(350) captures the plurality image signals sequentially in accordance with the decided capture sequence.

Description

The method and system for capture of the Multi-channel Image Signal

The present invention relates to a method and a system for capturing a multi-channel video signal. More particularly, the present invention relates to a method of improving a frame rate at the time of capture by analyzing a synchronization signal of an input multi-channel video signal and determining a capture order of video signals for each channel. And to the system.

In general, an image signal capture system receives an image signal photographed using a charge coupled device (CCD) camera through a plurality of channels, and converts the input image signal into a digital image signal using an image processing board. Save it.

1A is a view for explaining a video signal capture system 130 according to the prior art. Images 111 to 114 of FIG. 1A are images captured by cameras 121 to 124 installed in department stores. The cameras 121 to 124 that receive the image transmit the image signal associated with the image to the image signal capture system 130.

The video signal capture system 130 such as a digital video recorder (DVR) captures and stores the input video signal or transmits the captured video signal to a predetermined remote computer 150 through the communication network 140. do.

Such systems are widely used not only for security systems, but also in automated inspection equipment, multimedia systems, video conferencing and electronic commerce. In addition, with the recent rapid development of communication and the Internet, as more and more users want to view images at the field or remote sites, they want to receive video signals more clearly and quickly.

1B is a block diagram illustrating a video signal capture system 130 according to the prior art. The conventional video signal capture system 130 for receiving and storing video signals includes a multiplexer 132 and an image capture device 132. The multiplexer 131 receives a plurality of analog video signals (first to fourth analog video signals of FIG. 1B) input through a plurality of channels, and selects and outputs one of the one or more analog video signals.

The image capture device 132 captures each output image signal, and is responsible for converting an analog image signal into a digital image signal. Thus, the image capture device 132 includes an analog-to-digital converter. The image signal capture system according to another prior art may further include an image synchronization signal separator in addition to the apparatus of FIG. 1B. However, in the prior art, the sync signal extracted by the video sync signal separator is used to identify only the even and odd fields of the video signal.

2 is a timing diagram for explaining a multi-channel video signal capture method according to the prior art. 2A to 2D, timing diagrams for synchronization signals of video signals input through four channels of channels #A to #D are shown, respectively. 2 (e) shows an image signal corresponding to each channel when the images are captured in the order of channel (#A)-> channel (#B)-> channel (#C)-> channel (#D). Show the timing chart until all are captured. Hereinafter, an image signal when an image signal input for each channel is captured for each channel in a predetermined capture order will be referred to as a 'multi-channel capture image signal'.

Comparing the synchronization signal of the video signal input from the channel (#A) (Fig. 2 (a)) and the synchronization signal of the multi-channel capture video signal (Fig. 2 (e)) captured in the channel order, the channel ( It can be seen that the video signal of each channel is captured once while the synchronization signal of the video signal input from #A) is input five times. That is, if the video signal input to each channel is input at a frame rate of 30fps (frame per second) in the case of NTSC, the multi-channel captured video signal is captured at a frame rate of 4 * 30/5 = 24 fps. Therefore, even when there is no loss of the video signal or the loss of the frame rate in each channel, a number of problems may occur such that the image processing becomes unnatural because the frame rate of one channel is lowered and displayed at 6 fps.

The present invention has been made to improve the prior art as described above, by extracting the synchronization signal of the video signal for each channel to determine the optimal capture order and capture the multi-channel video signal in accordance with the capture order, frame that can be captured per second It is an object of the present invention to provide a method and system for increasing the number of frames to improve the frame rate.

It is still another object of the present invention to provide a method and system that can reduce the number of lost frames by updating the steps of extracting, storing, and capturing a synchronization signal corresponding to a channel at predetermined intervals to determine an optimal capture order. .

1A is a view for explaining a video signal capture system according to the prior art.

1B is a block diagram illustrating a video signal capture system according to the prior art.

2 is a timing diagram for explaining a multi-channel video signal capture method according to the prior art.

3 is a block diagram illustrating a multi-channel video signal capture system according to an embodiment of the present invention.

4 is a diagram for describing an image signal input from each channel according to one embodiment of the present invention;

5 is a view for explaining a multi-channel image capture system according to an embodiment of the present invention.

FIG. 6 is a diagram showing an example of data stored in a synchronization signal storage according to one embodiment of the present invention; FIG.

7 is a flowchart illustrating a method of capturing an image signal according to another embodiment of the present invention.

8 is an internal block diagram of a general purpose computer system that may be used in a multichannel video signal capture system in accordance with the present invention.

<Explanation of symbols for the main parts of the drawings>

310: multiplexer 320: synchronization signal storage unit

330: Sync signal storage unit 340: Capture order determination unit

350: video capture device

In order to achieve the above object and solve the problems of the prior art, the multi-channel video signal capture system according to the present invention is to receive a plurality of video signals from a plurality of channels, and to selectively output the plurality of video signals A multiplexer, a video sync signal separator for extracting a sync signal from the plurality of video signals, and a relative start time of a sync signal corresponding to each channel based on a sync signal of one video signal of the plurality of video signals And a synchronization signal storage unit for storing a period of a synchronization signal corresponding to each channel in each channel in association with a relative start time of the synchronization signal, and a capture order of the plurality of image signals based on the relative start time and the period. A capture order determination unit for determining a, and according to the determined capture order D. An image capture device for sequentially capturing the plurality of image signals.

According to one or more exemplary embodiments, a method for capturing a multi-channel video signal includes selectively outputting video signals from a plurality of input channels, extracting sync signals from the plurality of video signals, and one video signal from the video signals. Storing the relative start time of the synchronization signal corresponding to each channel and the period of the synchronization signal for each channel based on the synchronization signal of the channel, and corresponding to each channel based on the relative start time and the period for each channel. Determining a capture order of an image signal and sequentially capturing an image signal corresponding to each channel according to the capture order.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

3 is a block diagram illustrating a multi-channel video signal capture system according to an embodiment of the present invention. The multi-channel image signal capture system 300 includes a multiplexer 310, an image synchronization signal separator 320, a synchronization signal storage unit 330, a capture order determiner 340, and an image capture device 350.

The multiplexer 310 receives a plurality of analog video signals from a plurality of channels, and selects and outputs one of the plurality of analog video signals. In this case, the plurality of analog video signals are generally not synchronized with each other.

The image sync signal separator 320 extracts a sync signal from each of the video signals output from the multiplexer 310. FIG. 4 is a diagram for describing an image signal input from each channel, wherein the image signal is composed of a frame, and one frame is composed of an odd field and an even field. In another aspect, the frame consists of a blanking area and an active video area. The synchronization signal extracted from the image synchronization signal separator 320 may be a synchronization signal for distinguishing odd and even fields of the image signal, or a synchronization signal for distinguishing a blanking area and an active video area of the image signal, Or both of the synchronization signals. In addition, according to another embodiment of the present invention, in addition to the synchronization signal according to the field and the synchronization signal according to the region, it is possible to extract a synchronization signal determined according to specific conditions to be implemented.

The synchronization signal storage unit 330 stores the relative start time of the synchronization signal corresponding to each channel for each channel based on the synchronization signal of one of the image signals input from the plurality of channels. 5 is a diagram illustrating a multi-channel video signal capture system 300 according to the present embodiment. 5A to 5D are timing diagrams corresponding to sync signals of respective video signals input through four channels of channels #A to #D, as shown in FIG. to be.

For example, when the synchronization signal of the video signal input from the channel #A is set as the reference signal, the relative start time of the synchronization signal corresponding to the channel #A becomes '0', and other channels (# The relative start time of the synchronization signal corresponding to B, #C and #D) has a value greater than or equal to the relative start time of the reference signal. In this case, the period of the video signal input from each channel is regarded as the same value or a value within a predetermined error range.

The capture order determiner 340 determines a capture order of an image signal corresponding to each channel based on the relative start time for each channel stored in the sync signal storage 330.

For example, in FIG. 5, the relative start time of the synchronization signal corresponding to each channel is 4 msec (for channel #B), 6 msec (for channel #C), and 7 msec (channel #D), respectively. , The capture order determination unit 340, based on the period of the video signal input from each channel and the relative start time, as shown in (e) of FIG. The capture order is determined so as to capture video signals corresponding to the channel #D, the channel #C, and the channel #B.

That is, in case of capturing only odd fields, for example, the image signal, the image capturing apparatus 350 captures an image signal corresponding to the channel #A serving as a reference signal, and synchronizes the image signal with the synchronization signal A0 in time. After the falling edge (starting of the falling edge-Even Field), the video signal corresponding to the channel (#D) to which the rising edge (starting of the odd field) of the synchronization signal D0 comes.

According to another embodiment of the present invention, when capturing a frame image, instead of capturing one field like an odd field or an even field as in the above-described embodiment, when the rising edge ends (Odd-Even) After capturing, i.e. after capturing a pair of high and low regions, the image of the next frame is captured. In this embodiment as well, the frame rate is improved in the same manner as in the case of capturing only odd fields.

Meanwhile, due to the physical characteristics of the image capturing apparatus 350, there may be a period in which it is difficult to normally capture the next image signal for a predetermined time after capturing the predetermined image signal. That is, there may be a period in which the image capturing apparatus 350 operates unstable, which may be a method of implementing the image capturing apparatus 350 to implement the multi-channel image signal capturing system 300 according to the present embodiment. It depends on the device and the like for implementing the image capture device 350. Capturing an image signal in an unstable section can damage the image of the captured image. Therefore, after the falling edge of the synchronization signal A0 of the video signal corresponding to the channel #A, the rising edge of the synchronization signal D0 of the video signal corresponding to the channel #D is next. In addition, the image capturing apparatus 350 may not normally capture an image signal corresponding to the channel #D.

According to another embodiment of the present invention, as described above, the other channel in a period in which the image capture device 350 cannot capture another image signal immediately after capturing the image signal (hereinafter, referred to as an instability period). When there is a rising edge of the synchronization signal of the video signal of the multi-channel video signal capture system 300 skips without capturing the video signal of the other channel.

The instability period may be set differently according to an embodiment, and the multi-channel image signal capture system 300 may determine the capture order by further considering the instability period of the image capture device 350 in addition to the relative start time or period. have. Therefore, the multi-channel video signal capture system 300 according to the present embodiment not only improves the frame rate at the time of capturing the video signal, but also allows the video signal to be captured clearly and accurately.

In addition, according to another embodiment of the present invention, the synchronization signal storage unit 330 further stores the period of the synchronization signal corresponding to each channel in addition to the relative start time for each channel, and the capture order determination unit 340 is the The capture order is determined based on the period other than the relative start time. The capture order determined by the capture order determiner 340 may be further stored in the synchronization signal storage 330.

6 is a diagram illustrating an example of data stored in the synchronization signal storage unit 330 at this time. As shown in FIG. 6, the synchronization signal storage unit 330 stores relative starting points and periods of video signals corresponding to each channel for each channel. Since the actual period of the image signal corresponding to each channel is further stored, the capture order determiner 340 may determine the most efficient capture order.

The image capture device 350 captures an image signal corresponding to each channel according to the capture order determined by the capture order determiner 340. The image capture device 350 also functions as an analog-to-digital converter that converts an analog image signal into a digital image signal at the time of capture.

According to the present exemplary embodiment, the frame rate, which is a speed at which an image signal is captured in the image capturing apparatus 350, is significantly improved compared to the related art. In the case of capturing an image signal according to the prior art, in the prior art, as shown in FIG. 2, the image signal corresponding to each channel is output during the "5 cycles" of the image signal corresponding to the channel #A. Although each is captured once, according to the present embodiment, as illustrated in FIG. 5, an image signal corresponding to each channel is captured once during each of three cycles of the image signal corresponding to the channel #A. In other words, the rate at which the image signal is captured is increased by two cycles.

As such, according to the present embodiment, it is possible to capture a multi-channel video signal at an optimum frame rate by determining an appropriate capture order.

Further, according to another embodiment of the present invention, the multi-channel video signal capture system 300 updates the sync signal of the video signal of each channel at predetermined time intervals, and the relative start time (or period) of the updated sync signal. Determine the capture order.

The interval of the relative start time of the synchronization signal of the image signal may vary constantly. This is a phenomenon caused by the fact that the actual period of the video signal is slightly different even if it is assumed that the video signals of the same period are handled.

Accordingly, the image synchronization signal separator 320 extracts a synchronization signal of an image signal corresponding to each channel at predetermined time intervals, and the synchronization signal storage unit 330 stores a relative start time or period of the newly extracted synchronization signal. In addition, the capture order determiner 340 determines a capture order of an image signal corresponding to each channel based on the newly stored relative start time or period. In addition, the image capture device 350 captures an image signal corresponding to each channel in a newly determined capture order.

Through the 'update' process as described above, the multi-channel video signal capture system 300 can capture the video signal more efficiently (that is, fewer frames not captured at the timing that can be captured).

The predetermined time interval may be 'every time after the image capturing apparatus 350 captures an image signal corresponding to each channel once', or is set by an operator of the multi-channel image signal capturing system 300 according to the present embodiment. It may be one time interval or a time interval set by a user such as a purchaser of the multi-channel video signal capture system 300.

The shorter the time interval, the more efficient the frame rate of capturing the video signal corresponding to each channel becomes, but the time interval captures the video signal because it may act as a load on the multi-channel video signal capture system 300. In this case, it can be appropriately selected according to the required specifications.

Hereinafter, a video signal capture method according to another embodiment of the present invention will be described. 7 is a flowchart illustrating a video signal capturing method according to the present embodiment, and the video signal capturing method may be performed by the multi-channel video signal capturing system 300 described above.

The multi-channel video signal capture system 300 selectively outputs a plurality of video signals input from the plurality of channels in step 710, and in step 720 the video sync signal separator 320 uses the outputted video signals. Each sync signal is extracted.

In operation 730, the multi-channel video signal capturing system 300 sets the relative start time and period of the sync signal corresponding to each channel based on the sync signal of one of the plurality of video signals. Save it.

Data stored in the multi-channel video signal capture system 300 is as shown in FIG. 6.

According to another embodiment of the present invention, when the period of each video signal has the same value or a value within a predetermined error range, only the relative start time of the sync signal is stored.

In operation 740, the multi-channel video signal capturing system 300 determines a capture order of video signals corresponding to each channel based on the relative start time of each channel as shown in FIG. 6. The capture order may be determined by further considering a star period. The multi-channel video signal capture system 300 sequentially captures video signals corresponding to each channel according to the capture order determined in step 740.

As described above, when determining the capture order of the video signal corresponding to each channel and capturing the video signal according to the capture order, as shown in FIG. As described above with reference to FIGS. 5 and 6, the detailed description thereof will be omitted.

Further, according to another embodiment of the present invention, steps 720 to 740 are performed at predetermined time intervals. That is, once the capturing order is determined by performing the steps 720 to 740, the multi-channel video signal capturing system 300 captures the video signals in the determined capture order during the time interval, and then passes by the time interval. Steps 720 to 740 are again performed to capture the video signal according to the determined new capture order (which may be the same as the previous capture order) to maintain the frame rate optimally at capture.

Korea adopts the NTSC (national television system committee) method established by the US Television System Committee, and according to the broadcasting method, a video signal of one channel has a frame rate of 30 fps. For example, when a video signal having 30 fps is input to each of four channels, the multi-channel captured image is captured once every three cycles of the video signal corresponding to channel #A in FIG. 5, so that 4 * 30 [fps] / 3 = 40 [fps]. The number of frames per second is 16 frames per second more than a multi-channel captured image having 24 frames per second, which is a frame rate according to the related art described with reference to FIG. 2, and 10 frames more than a normal case (30 fps). For PAL with 25fps, 4 * 25 [fps] /3=33.3 [fps], 8.3 frames more than normal (25fps). As such, when the frame rate of the multi-channel captured image is increased, the frame rate at which the video signal corresponding to each channel is displayed is also improved, so that the displayed screen is more natural.

The present invention also provides a computer-readable recording medium for executing the image signal capture method according to the embodiment described above. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. The media may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks, such as floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. The medium may be a transmission medium such as an optical or metal wire, a waveguide, or the like including a carrier wave for transmitting a signal specifying a program command, a data structure, or the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like.

8 is an internal block diagram of a general purpose computer system that may be used in the multi-channel video signal capture system 300 described above.

Computer system 800 includes one or more processors 801 connected to a main memory including random access memory (RAM) 802 and read only memory (ROM) 803. The processor 801 is also called a central processing unit (CPU). As is well known in the art, the ROM 803 serves to transfer data and instructions to the CPU unidirectionally, and the RAM 802 typically transfers data and instructions bidirectionally. Used to. RAM 802 and ROM 803 may include any suitable form of computer readable media. Mass storage 804 is bidirectionally coupled to processor 801 to provide additional data storage capabilities, and may be any of the computer readable recording media described above. The mass storage device 804 is used to store programs, data, and the like, and is typically an auxiliary memory device such as a hard disk which is slower than the main memory device. Certain mass storage devices such as CD ROM 806 may be used. The processor 801 may include one or more input / output interfaces such as video monitors, trackballs, mice, keyboards, microphones, touchscreen displays, card readers, magnetic or paper tape readers, voice or handwriting readers, joysticks, or other known computer input / output devices. 805 is connected. Finally, the processor 801 may be connected to a wired or wireless communication network through the network interface 807. Through this network connection, the procedure of the method described above can be performed. The apparatus and tools described above are well known to those skilled in the computer hardware and software arts.

The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention.

According to the method and apparatus for capturing a multi-channel video signal according to the present invention, a frame capable of processing per second by extracting a synchronization signal of a video signal for each channel to determine an optimal capture order and capturing a multi-channel video signal according to the capture order You can improve the frame rate by increasing the number.

In addition, according to the present invention, the frame rate at the time of capture is improved by extracting the synchronization signal of the video signal for each channel at predetermined time intervals and updating the relative start time and period of the synchronization signal to determine the optimal capture order of the video signal. .

In addition, according to the present invention, since the frame rate at the time of capture is improved, screen drop-off phenomenon per channel is slowed down, and a good quality screen is provided to the user.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above-described embodiments, which can be variously modified and modified by those skilled in the art to which the present invention pertains. Modifications are possible. Accordingly, the spirit of the present invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications thereof will belong to the scope of the present invention.

Claims (9)

delete delete In the multi-channel video signal capture system, A multiplexer for receiving a plurality of video signals from a plurality of channels and selectively outputting the plurality of video signals; An image synchronization signal separator for extracting a synchronization signal from the plurality of image signals, respectively; The period of the synchronization signal corresponding to each channel in relation to the relative start time of the synchronization signal corresponding to each channel and the relative start time of the synchronization signal based on the synchronization signal of one of the plurality of image signals as a reference. A synchronization signal storage unit for storing the channel by channel; A capture order determination unit for determining a capture order of the plurality of video signals based on the relative start time and the period; And Image capture device for sequentially capturing the plurality of video signals in accordance with the determined capture order Multi-channel video signal capture system comprising a. In the multi-channel video signal capture system, A multiplexer for receiving a plurality of video signals from a plurality of channels and selectively outputting the plurality of video signals; An image synchronization signal separator for extracting a synchronization signal from the plurality of image signals, respectively; An image capture device for sequentially capturing the plurality of image signals; A synchronization signal storage unit for storing the relative start time of the synchronization signal corresponding to each channel based on the synchronization signal of one of the plurality of image signals for each channel, and for storing the instability period of the image capture device ; The instability period refers to a period during which the image capture device cannot capture any image signal normally; and A capture order determination unit for determining a capture order of the plurality of video signals based on the relative start time and the instability period Including, And the image capturing apparatus sequentially captures the plurality of image signals according to the capture order. In the multi-channel video signal capture method, Selectively outputting a plurality of video signals input from a plurality of channels; Extracting sync signals from the output video signals; On the basis of the synchronization signal of one of the plurality of image signals, the relative start time of the synchronization signal corresponding to each channel and the period of the synchronization time corresponding to each channel in association with the relative start time for each channel Storing each star; Determining a capture order of an image signal corresponding to each channel based on the relative start time; And Sequentially capturing an image signal corresponding to each channel according to the capture order Multi-channel video signal capture method comprising a. The method of claim 5, The step of extracting each of the synchronization signal, And extracting the synchronization signals at predetermined time intervals, respectively. delete A computer-readable recording medium having recorded thereon a program for executing the method of claim 5. The method according to claim 3 or 4, And the image synchronizing signal separator extracts the synchronizing signal at predetermined time intervals.