JP4595132B2 - Image distribution method, image display recording method, and program thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image distribution method suitable for use in a monitoring system, an image display recording method, and a program thereof.
[0002]
[Prior art]
(Definition)
First, terms used in this specification are defined. In this specification, “image size” means a data size (that is, bit length) after compression encoding for the same image signal as a reference. Therefore, in order to perform compression coding of an image signal with a “large image size”, it is effective to make the pixels finer and increase the resolution and to reduce the degree of compression, thereby decoding. A fine image can be obtained as a later image. Conversely, in order to perform compression encoding with a “small image size”, it is effective to reduce the resolution by coarsening the pixels and to increase the degree of compression, thereby reducing the data size. However, an inferior image can be obtained as a decoded image.
[0003]
(Background technology)
As shown in FIG. 10, images captured by monitoring cameras 221 installed at a plurality of locations are displayed on a monitor 232 at a single location by distributing the images through a communication line 240 such as a LAN (Local Area Network). There is known a monitoring system that enables monitoring. The image distribution device 220 includes a camera 221 and an image signal processing device 222, and the image signal processing device 222 compresses and encodes an image signal acquired by the camera 221 and outputs the image signal to the communication line 240. The terminal device 230 that receives the distribution of the image signal includes a terminal device main body 231 and a monitor 232. The terminal device main body 231 decodes the received image signal and displays the decoded image signal on the monitor 232. To a recording medium (not shown). The monitor 232 simultaneously displays a plurality of image signals received from a plurality of locations, for example, in a screen division format.
[0004]
[Problems to be solved by the invention]
By the way, in the conventional monitoring system, when the number of cameras 221 to be monitored at the same time increases, the image size is maintained at a normal size, and the frames are thinned out (that is, the number of frames is reduced), A measure has been taken to reduce the load on the communication line 240. In the monitoring image for the purpose of recording, real-time performance is not required, so the problem is slight even if the number of frames is reduced. However, in the monitoring image intended for display on the monitor 232, since real-time performance is important, there is a problem in that the quality of monitoring deteriorates if the number of frames is reduced.
[0005]
The present invention has been made to solve the above-described problems in the prior art, and reduces the load on the communication line while recording an image having a large image size, that is, excellent in fineness, and a small image size. That is, an object is to provide an image distribution method, an image display recording method, and a program thereof that can realize both the display of an image that is inferior in definition but does not impair the real-time property.
[0006]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided an image distribution method for distributing an image signal in a compression-encoded format, wherein (a) a signal indicating a recording interval and a display image size is received through a communication line. a step, constitute a (b) the image signal, each frame that is continuously input, and a step of distributing the recording frame and a display frame in a continuous state, the recording frame corresponding to the recording interval It is distributed at a predetermined number of frame intervals, and frames other than the recording frame are distributed as the display frame. (C) The compression encoding is performed on the display frame with an image size corresponding to the display image size. And (d) performing the compression encoding with an image size larger than the display image size for the recording frame, and (e) by the steps (c) and (d). The image signal whose serial compression encoding has been performed, further comprising the step of delivering through the communication line.
[0007]
According to a second aspect of the present invention, there is provided an image display recording method for receiving, displaying and recording a compressed encoded image signal via a communication line, and (A) a recording interval and a display image via the communication line. Transmitting a signal indicating a size; and (B) receiving the image signal distributed by the image distribution method of the first invention in response to the signal indicating the recording interval and the display image size. And (C) obtaining the decoded image signal by decoding the image signal received in the step (B), and (D) recording the recording frame of the decoded signal. And (E) displaying the display frame as an image in the decoded signal.
[0008]
According to a third aspect of the present invention, in the image display recording method of the second invention, the step (A) includes the recording interval and the display image to each of a plurality of communication partners through the communication line. The signal indicating the size is transmitted, and in the step (B), the image of the first invention is transmitted from each of the plurality of communication partners in response to the signal indicating the recording interval and the display image size. The step (C) receives the image signal distributed by a distribution method, and the step (C) decodes the image signal received in the step (B) and corresponding to each of the plurality of communication partners. The step (D) records the recording frame among the decoded signals corresponding to the plurality of communication partners, and the step (E) includes the plurality of communication partners. Single display on multiple split screens corresponding to The face is divided, said to each of the plurality of split screens, said display frames corresponding to display an image.
[0009]
According to a fourth aspect of the present invention, there is provided a program for causing a computer to execute the above steps in order to realize the method of any one of the first to third aspects on a computer.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
(1. Outline of image distribution system)
FIG. 1 is a block diagram showing a configuration of an image distribution system according to an embodiment of the present invention. The image distribution system 120 includes an image distribution device 20, a communication line 40, and a terminal device 30. In response to a distribution request from the terminal device 30, the image distribution device 20 compresses and encodes an image signal obtained by imaging with a camera and distributes the image signal to the terminal device 30 through the communication line 40. An example of the communication line 40 is a network such as a LAN or the Internet. The terminal device 30 is configured to decode the compression-encoded image signal output by the image distribution device 20 along the time, and to record and display an image. As shown in FIG. 1, the terminal apparatus 30 can also request distribution to a plurality of image distribution apparatuses 20 and receive distribution of compressed encoded image signals from the plurality of image distribution apparatuses 20.
[0011]
(2. Configuration of image distribution device)
FIG. 2 is a block diagram illustrating a configuration of the image distribution device 20. The image distribution device 20 includes an image signal processing device 21 that forms the main body of the image distribution device, and one or more cameras 22. The image signal processing device 21 includes a video decoder 23, a compression unit 24, an image recording unit 25, an interface 26, a control unit 27, a work memory 29, and a bus line 28 for connecting them together.
[0012]
An image signal obtained by imaging with the camera 22 is converted from an analog format to a digital format by the video decoder 23. When a plurality of cameras 22 are connected to the video decoder 23, the plurality of cameras 22 are sequentially switched, for example, one frame at a time or every predetermined time. That is, any one of the plurality of cameras 22 is selected over time, and an image signal obtained by imaging the selected camera 22 is input to the video decoder 23. The digital image signal output from the video decoder 23 is compressed and encoded by the compression unit 24.
[0013]
The work memory 29 is a memory for temporarily holding an image signal in the course of compression encoding processing. The compression-coded image signal output from the compression unit 24 is recorded in the image recording unit 25 or sent to the interface 26. Recording in the image recording unit 25 and transmission to the interface 26 can be performed simultaneously. When the interface 26 is connected to the external communication line 40, the interface 26 sends the compression-coded image signal output from the compression unit 24 or the compression-coded image signal recorded in the image recording unit 25 to the communication line 40. To do.
[0014]
The control unit 27 is composed of, for example, a CPU (computer) that operates based on a program (software), and has a function of controlling the elements 23 to 26 and 29. When the control unit 27 is composed of a CPU, the work memory 29 or the image recording unit 25 also functions as a memory that stores a program that defines the operation of the CPU. The compression unit 24 is configured by a semiconductor chip (LSI) that executes compression of an image signal only by hardware, for example. Some or all of the elements 23 to 27 and 29 included in the image signal processing device 21 may be constituted by a single semiconductor chip (LSI or system LSI), and the whole is a single semiconductor. A chip (system LSI) may be used.
[0015]
As described above, the image distribution device 20 is configured to be able to output a compression-encoded image signal to the communication line 40 in synchronization with the image signal input from the camera 22, that is, in real time. . Further, since the image recording unit 25 for recording the compression-encoded image signal is provided, not only the compression-encoded image signal can be distributed but also recorded according to the purpose and conditions. Further, instead of real-time distribution, the recorded compressed and encoded image signal can be read from the image recording unit 25 and sent to the communication line 40 through the interface 26.
[0016]
(3. Configuration of terminal equipment)
FIG. 3 is a block diagram showing an internal configuration of the terminal device 30. The terminal device 30 includes a terminal device main body 31 and a monitor 32. The terminal device main body 31 includes an interface 33, an expansion unit 34, an image storage unit 35, a video encoder 36, a control unit 37, a recording medium 39, and a bus line 38 for connecting them together. The interface 33 is connected to the communication line 40, thereby communicating with the image distribution apparatus 20 through the communication line 40. The decompressing unit 34 decodes the compression-coded image signal received by the interface 33. The decoded image signal obtained by decoding is recorded on the recording medium 39 or sent to the video encoder 36. Recording on the recording medium 39 and transmission to the video encoder 36 can be performed simultaneously.
[0017]
The video encoder 36 converts the decoded image signal output from the decompression unit 34 or the decoded image signal recorded on the recording medium 39 from a digital format to an analog format. The analog image signal output from the video encoder 36 is input to the monitor 32. The monitor 32 displays the input analog image signal on the screen.
[0018]
The control part 37 is comprised by CPU which operate | moves based on a program (software), for example, and has fulfill | performed the function which controls each element 33-36,39. The control unit 37 may be configured by an LSI including only hardware instead of the CPU. The image storage unit 35 is a work memory for temporarily holding an image signal in the course of processing by the decompression unit 34. When the control unit 37 is formed of a CPU, the image storage unit 35 also functions as a memory that stores a program that defines the operation of the CPU. Some or all of the elements 33 to 37 and 39 included in the terminal device main body 31 may be formed of a single semiconductor chip (LSI or system LSI), and the whole is a single semiconductor. A chip (system LSI) may be used.
[0019]
(4. Operation of image distribution system)
FIG. 4 is a flowchart showing an operation procedure of the image distribution system 120. FIG. 5 is a flowchart showing an internal procedure of a part of the processing of FIG. Further, FIGS. 6 to 8 are operation explanatory diagrams of the image distribution system 120.
[0020]
In the image distribution system 120, when the terminal device 30 transmits a distribution request signal to the image distribution device 20 through the communication line 40 (step ST11), the image distribution device 20 cancels the standby state (step ST1). Subsequently, the terminal device 30 transmits a signal instructing the recording interval and a signal instructing the display image size to the image distribution device 20 (step ST12). The process of step ST12 may be performed simultaneously with the process of step ST11. The signals transmitted in steps S11 and S12 are generated by, for example, the control unit 37 (FIG. 3) and transmitted through the interface 33.
[0021]
Next, the image distribution device 20 executes compression encoding of the image (step ST2). The process of step ST2 is executed by the compression unit 24, and the procedure is shown in FIG. In step ST21, the image signal is input to the compression unit 24 for each frame. As illustrated in FIG. 2, when a plurality of cameras 22 are connected to the video decoder 23, a frame sent from the camera 22 selected at each time point is input.
[0022]
In the next step ST22, as illustrated in FIG. 6, the input frame is distributed to either the recording frame F1 or the display frame F2. The recording frame F1 is a frame suitable for the terminal device 30 as a distribution partner to record an image on the recording medium 39, and the display frame F2 is a frame suitable for the terminal device 30 to display an image on the monitor 32. It is. In step ST22, the input frame is allocated to the recording frame F1 at a frame interval corresponding to the instructed recording interval. FIG. 6 shows an example in which the designated recording interval is 4 frames.
[0023]
The recording frame F1 is compression-encoded with a normal image size, that is, with a resolution and compression rate that place importance on the fineness of the image (step ST24). On the other hand, the display frame F2 is compression-encoded with the instructed display image size (step ST23). In step ST12 described above, the terminal device 30 instructs the image size of the frame to be displayed on the monitor 32 as the display image size. This display image size is set smaller than the image size of the frame intended for image recording. Therefore, as schematically shown in FIG. 7, the display frame F2 is compressed and encoded with an image size smaller than that of the recording frame F1. Thereafter, the compression-encoded frame F1 or F2 is output from the compression unit 24 in the form of a bit stream (step ST25). FIG. 8 schematically shows how the sequence of frames input to the video decoder 23 is handled in the subsequent processing.
[0024]
Returning to FIG. 4, when the process of step ST2 is completed for one frame, the frame F1 or F2 output from the compression unit 24 is delivered to the terminal device 30 through the interface 26 and the communication line 40 (step ST5). ). At the same time, when recording is to be performed (step ST3), the frame F1 or F2 output from the compression unit 24 is recorded on the recording medium 39 (step ST4). In step ST5, the frame F1 or F2 once recorded on the recording medium 39 may be read and distributed. That is, the frame F1 or F2 output from the compression unit 24 may be distributed via the recording medium 39.
[0025]
The terminal device 30 receives the delivered frame F1 or F2 by the interface 33 (step ST5) and decodes it by the decompression unit 34 (step ST13). Frames F1 and F2 having different resolutions or compression rates are decoded by a procedure corresponding to each compression encoding. If the decoded frame is the recording frame F1 (step ST14), it is recorded on the recording medium 39 (step ST16), and if it is the display frame F2 (step ST14), it is displayed on the monitor 32 through the video encoder 36 (step ST14). Step ST15).
[0026]
When step ST15 or ST16 is completed for one frame, the control unit 37 determines whether or not to end the process (step ST17). For example, when it is determined that the terminal device 30 should be terminated, such as when the user of the terminal device 30 instructs termination, the control unit 37 transmits a signal notifying the end of distribution to the image distribution device 20 (step ST19). The communication is terminated (step ST20). On the other hand, if it is determined that the process should not be terminated, the control unit 37 returns the process to step ST12 if the instruction content regarding the recording interval or the display image size needs to be changed (step ST18). New instruction contents are transmitted to the image distribution apparatus 20. On the other hand, when it is not necessary to change the instruction content (step ST18), the control unit 37 returns the process to step ST5 so that the interface 33 receives a new frame.
[0027]
In the image distribution apparatus 20, when the distribution of the compression-encoded image signal (step ST5) and the necessary recording (step ST4) are completed, the control unit 27 determines whether or not the process should be terminated (step ST6). When it is determined that the process should be terminated, such as when a signal for notifying the end of distribution has been received or when the operator of the image distribution apparatus 20 has instructed the termination, the control unit 27 communicates with the terminal device 30. Communication is terminated (step ST7). On the other hand, while it is determined that the processing should not be terminated, the control unit 27 performs the processing from reception of new instruction contents (step ST12) or compression / encoding processing of the image signal (step ST2) to step ST6 for each frame. Repeat.
[0028]
Since the image distribution system 120 operates as described above, the terminal device 30 indicates the size of the image to be displayed on the screen as the display image size, and also indicates the frame interval of the image to be recorded as the recording interval. While reducing the load on the communication line 40, it is possible to simultaneously record an image having a large image size, that is, excellent in definition, and displaying an image having a small image size, that is, inferior in definition but not impairing real-time characteristics. be able to.
[0029]
(5. Operation when receiving distribution from multiple image distribution devices)
As illustrated in FIG. 1, when the terminal device 30 receives distribution of the compression-encoded image signal from the plurality of image distribution devices 20, the terminal device 30 individually distributes to each of the plurality of image distribution devices 20. A request (step ST11), a signal indicating the recording interval, and a signal indicating the display image size (step ST12) may be transmitted. And it is good to perform the process of step ST13-ST19 with respect to the flame | frame which each of the some image delivery apparatus 20 delivers. Of the frames distributed by each image distribution device 20, the number of recording frames F1 having a large image size is limited by the recording interval, and the display frame F2 has a small image size. Frames distributed by the distribution device 20 can be processed with a light burden.
[0030]
The frames distributed by the plurality of image distribution apparatuses 20 are simultaneously displayed on a single display screen of the monitor 32 in a screen division format as illustrated in FIG. In FIG. 9, nine sections numbered 1 to 9 represent divided screens corresponding to the nine image distribution apparatuses 20. Thereby, taking advantage of the small image size of the display frame F2, the display frames F2 distributed from the plurality of image distribution apparatuses 20 can be simultaneously viewed. It is desirable that the display image size that the terminal device 30 instructs to each image distribution device 20 corresponds to the size of the corresponding divided screen. As a result, it is possible to display an image with a fine definition between a plurality of divided screens.
[0031]
【The invention's effect】
In the method according to the first aspect of the present invention, a frame constituting an image signal to be compression-encoded is divided into a recording frame and a display frame in accordance with a recording interval instructed through a communication line. The display frame is compression-encoded with an image size corresponding to the display image size instructed through the communication line, and the recording frame is compression-encoded with an image size larger than that. For this reason, the terminal device connected to the communication line indicates the size of the image to be displayed on the screen as the display image size, and also indicates the frame interval of the image to be recorded as the recording interval, and distributes in response thereto From the compressed and encoded image signal, the display frame can be displayed on the screen and the recording frame can be recorded on the recording medium. As a result, while reducing the load on the communication line, recording a fine image with a large image size, that is, a high resolution and a low compression ratio, and a small image size, that is, a resolution because the resolution is low or the compression ratio is high. Although it is inferior, it is possible to simultaneously display an image without impairing real-time performance.
[0032]
In the method according to the second aspect of the present invention, the display frame is displayed on the screen and the recording frame is recorded on the recording medium from the compressed encoded image signal distributed by the method according to the first aspect. Therefore, the size of the image to be displayed on the screen is instructed as the display image size, and the frame interval of the image to be recorded is instructed as the recording interval, thereby reducing the load on the communication line and increasing the image size. That is, it is possible to simultaneously realize recording of an image having excellent definition and display of an image having a small image size, that is, inferior definition but not impairing real-time characteristics.
[0033]
In the method according to the third aspect of the present invention, image signals are distributed from a plurality of communication partners, and a single display screen is divided into a plurality of divided screens corresponding to the plurality of communication partners. The corresponding display frame is displayed as an image on each of the above. For this reason, taking advantage of the small image size of the display frame, it is possible to simultaneously view the display frames distributed from a plurality of communication partners.
[0034]
In the program according to the fourth aspect of the present invention, the method according to each of the first to third aspects can be executed by being installed in a computer.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an image distribution system according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of the image distribution apparatus in FIG. 1;
FIG. 3 is a block diagram showing a configuration of the terminal device of FIG. 1;
4 is a flowchart showing an operation procedure of the image distribution system of FIG. 1;
FIG. 5 is a flowchart showing an internal procedure of step ST2 of FIG.
6 is an operation explanatory diagram showing an operation of the image distribution system of FIG. 1. FIG.
7 is an operation explanatory diagram showing an operation of the image distribution system of FIG. 1. FIG.
8 is an operation explanatory diagram showing an operation of the image distribution system of FIG. 1. FIG.
FIG. 9 is an operation explanatory diagram showing an operation of the image distribution system of FIG. 1;
FIG. 10 is a block diagram illustrating a configuration of an image distribution system according to a conventional technique.
[Explanation of symbols]
20 Image distribution device 30 Terminal device 40 Communication line F1 Recording frame F2 Display frame

Claims (4)

An image distribution method for distributing an image signal in a compression-encoded format,
(a) receiving a signal indicating a recording interval and a display image size through a communication line;
(b) constituting said image signal, each frame that is continuously input, and a step of distributing the recording frame in a continuous state with the display frame, the recording frame is a predetermined number corresponding to the recording interval Sorted at frame intervals, frames other than the recording frame are sorted as the display frame,
(c) performing the compression encoding on the display frame with an image size corresponding to the display image size;
(d) performing the compression encoding on the recording frame with an image size larger than the display image size;
(e) further comprising the step of distributing the image signal subjected to the compression encoding in the steps (c) and (d) through the communication line.
Image delivery method. An image display recording method for receiving, displaying and recording a compressed encoded image signal via a communication line,
(A) transmitting a signal indicating a recording interval and a display image size through the communication line;
(B) receiving the image signal distributed by the image distribution method according to claim 1 in response to the signal indicating the recording interval and the display image size;
(C) obtaining a decoded image signal by decoding the image signal received in the step (B);
(D) recording the recording frame of the decoded signal;
(E) A step of displaying the display frame as an image in the decoded signal. The step (A) transmits the signal indicating the recording interval and the display image size to each of a plurality of communication partners through the communication line,
The image signal distributed by the image distribution method according to claim 1, wherein the step (B) responds to the signal indicating the recording interval and the display image size from each of the plurality of communication partners. Receive
The step (C) obtains the decoded image signal by decoding the image signal corresponding to each of the plurality of communication partners received in the step (B),
The step (D) records the recording frame of the decoded signal corresponding to each of the plurality of communication partners,
The step (E) divides a single display screen into a plurality of divided screens corresponding to the plurality of communication partners, and displays the corresponding display frame as an image on each of the plurality of divided screens. The image display recording method according to claim 2.   A program for causing a computer to execute each of the steps in order to realize the method according to any one of claims 1 to 3 on a computer.

Images