JPH09307880A - Radio supervisory system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To configure the radio supervisory system employing spread spectrum communication with a transmission function only for a transmission station and with a reception function only for a reception station. SOLUTION: Each of transmission. stations samples an analog video signal from a camera 1 to convert it into a digital signal, the signal is compressed and the resulting signal is stored in a 1st memory section 4. A control section 5 controlling storage and read of the 1st memory section 4 reads stored video data according to a timing predetermined in the transmission station and sends the read video data to a reception station via a transmission processing section 12. Furthermore, the transmission timing is assigned in advance to each transmission station in the order and a plurality of the transmission stations send the video data sequentially one by one station. A reception station stores video data from each slave station to a 2nd memory section 29 and after the lapse of transmission finish time from all the slave stations based on a clock section 30, data are read from the memory section 29 and a multi-screen video image is displayed on a monitor 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum communication wireless monitoring system, and more particularly, to a plurality of transmitting stations provided with video cameras and a receiving station for monitoring based on camera images from these transmitting stations. The present invention relates to a wireless monitoring system in which a transmitting station is configured with a transmitting function only and a receiving station is configured with a receiving function only.

[0002]

2. Description of the Related Art Conventionally, in a camera monitoring system, a video signal from each camera (61 to 64) is sent to a controller 66 using a cable (cable) 65 as shown in FIG. Or, it was displayed on the monitor 67 after being processed by four screens. In addition to the above wired method, as shown in FIG. 5, the video signal of the camera 51 is analog-modulated or digital-modulated, and the transmitter 52 and the antenna 53.
There is a method of transmitting to the receiving station by a more wireless signal. The receiving station monitors 56 the video signals received by the antenna 54 and the receiver 55.
To be projected.

[0003]

However, the above-mentioned wired method requires wiring work for the transmission cable, which makes it difficult to quickly deal with the case of relocation. On the other hand, in the case of the wireless type, there is no need to carry out wiring work for the transmission cable, and therefore it has the advantage of being able to quickly cope with cases such as relocation, but on the other hand, when transmitting video data by analog modulation, a wide band is required. In the case of digital modulation, it is necessary to increase the transmission power in order to improve the resistance to interference, and when transmitting multiple camera images, carrier frequency signals for the number of cameras are required. There is a drawback that Furthermore, in the case of wireless type,
Signal transmission / reception for designating one of a plurality of cameras is required. Therefore, both the camera side and the receiving station side have a transmission / reception function, and the receiving station side transmits a signal designating the camera side. After the side receives this, the camera side which received the designation transmits the image, and the receiving station receives the image. It is an object of the present invention to provide a monitoring system that improves on various drawbacks of such conventional methods.

[0004]

According to the present invention, there is provided a first memory section for storing camera image data, a transmitting section for transmitting camera image data read from the first memory section by a radio signal, and a time period. A clock unit for managing, and a second memory unit for storing a preset transmission period,
A transmitting station including a control unit that controls transmission so that camera image data is transmitted only during a set period based on the time by the clock unit and the transmission period stored in the second memory unit. It is configured by a plurality and one receiving station that receives a transmission signal related to camera image data from each of the transmitting stations, and the periods transmitted by each of the plurality of transmitting stations are set in order by time division in advance. A wireless monitoring system is provided.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Each transmitting station side samples an analog video signal from a camera into digital data, compresses the data, and stores the data in a first memory section. A control unit for controlling storage and reading of the first memory unit reads the stored video data according to a timing predetermined for the transmitting station, and the read video data to a receiving station via a transmitting unit. Send. The above-mentioned transmission timings are ordered and assigned in advance for each transmitting station, and video data is transmitted from a plurality of transmitting stations one by one in order.

The receiving station receives this. When the receiving station displays images from a plurality of transmitting stations (for example, 4 transmitting stations) as a multi-screen (4 screens) on the monitor, the demodulated video data is sequentially stored in the video memory unit and the receiving station receives the demodulated video data. Based on the clock unit provided, when one transmission from all the transmitting stations has completed one cycle, the video data is read out according to the procedure determined by the memory unit, multi-screen processed and displayed. As an alternative to this multi-screen, the transmitting station transmits the transmitting station identification code together with the video data, and the receiving station separates the transmitting station identification code by the separating unit. Based on the separated identification code, it is determined whether reception of all transmitting stations has been completed (identification code memory unit and determination unit), and when the same determination is made, video data is read from the memory unit, and multi-screens are displayed in the same manner as above. To process.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A wireless monitoring system according to the present invention will be described below with reference to the drawings. 1 is a block diagram of essential parts showing an embodiment of a wireless monitoring system according to the present invention, FIG. 2 is a block diagram of essential parts showing another embodiment, and FIG. 3 is a transmission timing diagram of each transmitting station. 1 and 2, the upper part shows a transmitting station and the lower part shows a receiving station. The concept of this system is as shown in FIG. 5, and the transmitting station is usually composed of a plurality of stations (four stations in the figure), but FIGS. 1 and 2 show one transmitting station among them. In the following, description will be made separately for FIG. 1 and FIG.

(1) Description of operation of the embodiment shown in FIG. 1 An analog video signal from the camera 1 is sent to an input processing section 2, and the processing section 2 performs sampling processing based on a clock signal of a required frequency to obtain digital video data. Convert.
The digital video data is subjected to image compression processing (for example, MPEG, JPEG, etc.) by the compression processing unit 3 based on a required method,
It is stored in the first memory unit 4. The stored video data is read as parallel data at a predetermined timing described later. Storage and reading of the first memory unit 4 are performed under the control of the control unit 5. A clock unit 6 and a second memory unit 7 are connected to the control unit 5. The parallel data read from the first memory unit 4 is parallel-serial (P
-S) The data is sent to the converter 8, where it is converted to serial data and sent to the data synthesizer 9. The data from the header generator 10 is input to the synthesizer 9.

The header generator 10 generates necessary data required for communication (synchronization supplementary data, radio station call code, etc.). The synthesizing unit 9 adds the additional data generated by the header generating unit 10 to the camera image data. The video data to which the required data is added by the synthesizing unit 9 is a modulating unit.
Sent to 11. The modulator 11 performs spread spectrum modulation using a required spread code. This spread modulation signal is sent to the transmission processing unit 12, where it is subjected to conversion processing to a required transmission frequency and amplification processing to a required power. After the same process,
It transmits to the receiving station via the antenna 13. The above is the flow of signal processing.

Here, the transmission timing will be described. In this system, the timing of transmission by each transmitting station is sequenced and assigned in advance to each of a plurality of transmitting stations. FIG. 3 is a transmission timing diagram when the number of transmitting stations is four. In the figure, the transmitting station 1 is set between the reference time (0 mS) and 120 mS with respect to a certain time,
This is an example in which 5 mS of the same 120 mS to 125 mS is set as a rest period, and 125 mS to 245 mS after the passage of the rest period is assigned to the transmitting station 2, hereafter, similarly to the transmitting station 3 and the transmitting station 4. The idle period is provided to avoid duplication with other stations.
As a result, the transmission from the four transmitting stations is completed in one cycle in the period of 500 mS. Hereinafter, the second transmission is repeated. As shown in the figure, 2 images from each transmitting station per second, total 8
The video will be transmitted.

The transmission timing of each transmitting station is managed by the read timing from the first memory unit 4. That is, the data is read from the memory unit 4 in accordance with the transmission timing assigned by the transmitting station.
The management of the transmission timing is performed based on the clock unit 6 and the second memory unit 7. The clock unit 6 is common to all transmitting stations and serves as a reference for time and elapsed time.
In addition, the second memory unit 7 stores the data relating to the transmission timing assigned to the transmitting station. Control unit 5
Reads data from the first memory unit 4 at a predetermined timing based on the clock unit 6 and the second memory unit 7. The read data is transmitted through the flow described above. The receiving station receives the signal transmitted from each transmitting station as described above. As a video monitoring method at this receiving station,
There are a method of switching the transmitting stations one by one and a method of increasing the number of screens for monitoring, but this embodiment will be described on the premise of increasing the number of screens. In addition, this multi-screen is set to four screens.

The camera image data received by the antenna 21 of the receiving station is input to the reception processing section 22 and subjected to necessary processing such as amplification and intermediate frequency conversion. After the same processing, it is sent to the demodulation unit 23.
The demodulation unit 23 performs spread spectrum demodulation using the same spreading code as that of each transmitting station. The data demodulated by the demodulation unit 23 is sent to the data separation unit 24. Same separation section
At 24, the video data obtained by separating the additional data is obtained. The video data is sent to the serial-parallel (SP) converter 25 and converted from serial data to parallel data. The converted parallel video data is temporarily stored in the first memory unit 26 under the control of the control unit 27 and then sequentially read out. The read video data is subjected to data expansion processing by the data expansion processing unit 28, and is restored to digital data before compression processing on the transmitting station side. The same data is stored in the second memory unit 29 under the control of the control unit 27. The storage in the second memory unit 29 is performed until four screens from the transmitting station 1 to the transmitting station 4 are stored. When four screens have been stored, the data is read from the second memory unit 29 under the control of the control unit 27. Whether or not the video data for four screens is stored is managed based on the elapsed time by the clock unit 30. That is, as described above, the transmission timing is assigned to each transmitting station, and the time for one transmission cycle is known. Therefore, the data is read from the second memory unit 29 every time the time for one transmission cycle elapses.

FIG. 4A is a timing chart for storing and reading the video data from the transmission station 1 (camera 1) to the transmission station 4 (camera 4) in the second memory section 29. Images 1 to 4 in FIG. 6B correspond to images from the cameras (1) to (4) in FIG. In order to obtain the four screens in FIG. 6B, for the upper half of the vertical direction, the image 1a is displayed in the first half period of the horizontal line and the image 2a is formed in the second half of the horizontal line. For the lower half of the vertical line, the image 3a may be read during the first half of the horizontal line and the image 4a may be read during the latter half of the horizontal line. In this reading, data thinning is performed. The video data read from the second memory unit 29 in this manner is sent to the output processing unit 31 and converted from a digital signal to an analog signal (D / A conversion).
Etc. to process the monitor video. The video signal from the output processing unit 31 is sent to the monitor 32 to display a 4-screen image as shown in FIG. The clocks installed in the transmitting station and the receiving station receive standard radio waves for time standard (short-wave broadcasting, etc.) and calibrate them periodically based on the radio waves to maintain their accuracy. it can.

(2) Description of Operation of Embodiment of FIG. 2 In FIG. 2, the same parts as those in FIG. 1 are designated by the same reference numerals. 2 is different from FIG. 1 in that the read start timing from the second memory unit 29 in the case of forming a four-screen image on the receiving station side is another method. Specifically, each transmitting station transmits a transmitting station identification code that identifies the transmitting station together with video data, and the receiving station determines the start of reading based on the transmitting station identification code. Is. Therefore, each transmitting station causes the header generating section 10 to generate data related to the transmitting station identification code in addition to the above-mentioned data. The data of the same identification code is further added to the video data (data synthesizing unit 9), and the added video data is transmitted.

On the other hand, the receiving station side separates and outputs not only the video data but also the data relating to the transmitting station identification code as a function of the separating section 24. Of the separated outputs, the video data is processed in the same manner as in FIG. 1, and the transmission station identification code is stored in the third memory unit 33 via the control unit 27. The determination unit 34 determines which transmission station the transmission station identification code stored in the memory unit 33 belongs to. When the determination unit 34 determines that the identification codes of all the transmitting stations have been received, the control unit 27 starts reading data from the second memory unit 29. This reading is performed by the same method as described in the previous section. This enables the same 4-screen processing (FIG. 4B) as in the case of FIG.

[0016]

As described above, according to the present invention, in a monitoring system for monitoring based on a plurality of camera images,
Since a plurality of camera images are transmitted to the receiving station in a time division manner, a simple system configuration is possible in which only the transmitting function is on the camera side and only the receiving function is on the receiving station side. In addition, since video data is transmitted from the camera side (transmitting station) to the receiving station by wireless communication using a spread spectrum method, communication with low power is possible and secrecy can be secured.

[Brief description of drawings]

FIG. 1 is a block diagram of essential parts showing an embodiment of a wireless monitoring system according to the present invention.

FIG. 2 is a principal block diagram showing another embodiment of the wireless monitoring system according to the present invention.

FIG. 3 is a transmission timing chart from the transmitting station in FIG.

FIG. 4A is a timing chart of storage and reading with respect to the second memory unit 29 in FIG. 1, and FIG. 4B is an explanatory diagram of a 4-screen image.

FIG. 5 is a principle configuration diagram for explaining a wireless monitoring system.

FIG. 6 is a principle configuration diagram for explaining a conventional monitoring system.

[Explanation of symbols]

 1 camera 3 data compression processing unit 4 transmission station first memory unit 5 transmission station control unit 6 transmission station clock unit 7 transmission station second memory unit 9 data synthesis unit 10 header generation unit 11 modulation unit 23 demodulation unit 24 separation unit 26 Reception station first memory section 27 Reception station control section 28 Data expansion processing section 29 Reception station second memory section 30 Reception station clock section 33 Reception station third memory section 34 Discrimination section

Claims (5)

[Claims] 1. A first memory unit for storing camera image data, a transmitting unit for transmitting the camera image data read from the first memory unit by a wireless signal, a clock unit for managing time, and a preset unit. A second memory unit storing the transmitted transmission period, and a camera image only for a set period based on the time by the clock unit and the transmission period stored in the second memory unit. A plurality of transmitting stations each including a control unit that controls transmission so as to transmit data, and one receiving station that receives a transmission signal related to camera image data from each of the transmitting stations, and the plurality of transmitting stations. A wireless monitoring system in which the periods transmitted by each station are set in advance by time division. 2. The control means is adapted to read the video data stored in the first memory unit during a transmission period stored in the second memory unit for transmission control in each of the transmitting stations. The wireless monitoring system according to claim 1, wherein the first memory unit is controlled. 3. The wireless monitoring system according to claim 1, wherein the wireless signal is a spread spectrum signal. 4. The receiving station controls a memory section for storing video data transmitted from each of the transmitting stations in a time division manner, a clock section for time management, and the memory section based on the clock section. And a control unit for reading the video data from the memory unit according to a predetermined procedure when the time from each of the plurality of transmission stations by time division has passed one cycle. 1. The monitoring system according to 1. 5. Each of the transmitting stations is provided with data synthesizing means for adding a transmitting station identification code for identifying the transmitting station to the camera image data, while the receiving station is time-divided from each of the transmitting stations. A header separating unit that separates the image data and the transmitting station identification code based on the transmitted image data to which the transmitting station identification code is added; and a video memory unit that stores the image data from the header separating unit, An identification code memory section for storing the transmission station identification code from the header separating means, a determination section for determining which transmission station the transmission station identification code of the memory section is, and the video memory section, And a control unit for controlling the identification code memory unit and the discrimination unit, wherein when the discrimination unit discriminates all the transmission station identification codes of the transmission stations, 2. The surveillance system according to claim 1, wherein the video data is read from the video memory unit according to a predetermined procedure.