JP2001086484A - Radio monitor system, display device and monitor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio monitor system, a display device and a monitor device with which data including much information can be simultaneously transmitted at a high speed between a plurality of transmitters/receivers by using a direct spread spectrum modulation. SOLUTION: Each of the display device and the monitor device is provided with RF modules and direct spread spectrum modem parts for performing transmission/reception while switching a plurality of channels. A display device (a) establishes communications with a monitor device (c) by using a control channel (G channel) (S4 and S8) and transmits data by using a transmitting channel (A channel) and the direct spread spectrum modulation (S10 and S26). A display device (b) similarly establishes communications by using the G channel (S44 and S48) and transmits data by using a C channel (S52).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a system for monitoring a subject on a monitor installed at a place distant from a camera, and more particularly to a wireless monitoring system for transmitting image signals from a plurality of cameras to a plurality of monitors.

[0002]

2. Description of the Related Art In a conventional surveillance system using a camera and a monitor, cable connection work is required when the system is installed in order to connect the camera and the monitor by wire. Therefore, a monitoring system by wireless connection has been proposed for the purpose of eliminating this wiring work. In particular, Japanese Patent Application Laid-Open No. 9-163355 discloses a wireless monitoring system that transmits image data having a large amount of information from a camera to a monitor by using a modulation method using a spread spectrum. A wireless monitoring system according to the present invention includes a plurality of slave stations transmitting a wireless signal modulated with an image signal from a television camera, and a plurality of master stations receiving a wireless signal, demodulating the image signal, and displaying the demodulated image signal on an image monitor. including. According to the present invention, an image request signal is transmitted from a master station to a specific slave station,
Only the specific slave station that has received the image request signal and the master station that has transmitted the image request signal transmit and receive image data.

Accordingly, even when data having a large amount of information such as image data is transmitted by using a modulation method using a spread spectrum, a master station and a slave station that transmit and receive simultaneously are one station each. Therefore, interference does not occur.

[0004]

One of the features of the modulation method using the spread spectrum is that the transmission bandwidth is widened and the number of channels per frequency bandwidth is increased. When the modulation method using the spread spectrum is applied to high-speed transmission of image data with a large amount of information, the types of spread codes that can be used within a limited band are limited, and interference occurs when a plurality of devices perform transmission and reception simultaneously. The above-mentioned invention is an invention made to solve this. Since there is only one slave station for transmitting and one master station for receiving, interference can be avoided.

However, in a monitoring system having a plurality of master stations and a plurality of slave stations, if image data cannot be transmitted simultaneously between the plurality of master stations and slave stations, a plurality of monitors are required. Even so, only one camera can display real-time images from one camera on one monitor.

On the other hand, a modulation system using a spread spectrum has many features such as secrecy.

Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a real-time property while maintaining the characteristics of a modulation system using a spread spectrum. It is an object of the present invention to provide a wireless monitoring system, a display device, and a monitoring device that can transmit data with a large amount of information at a high speed and can simultaneously transmit data to a plurality of transmitting and receiving stations.

[0008]

A wireless monitoring system according to a first aspect of the present invention is a wireless monitoring system including a plurality of display devices and a plurality of monitoring devices, wherein each of the display devices stores data. Modulation / demodulation means for modulating / demodulating by the spread spectrum method, and transmission means connected to the modulation / demodulation means for transmitting / receiving data modulated by the spread spectrum method using any one of a plurality of channels within a predetermined frequency band. And, an image request signal to the monitoring means, a signal transmission means for transmitting to the modulation and demodulation means for transmission, via the transmission means and the modulation and demodulation means, image data receiving means for receiving image data from the monitoring device, Display means for displaying an image received by the receiving means,
Each monitoring device is connected to modulation and demodulation means for modulating and demodulating data by a spread spectrum method and modulation and demodulation means of the monitoring device, and transmits data modulated by the spread spectrum method to any one of a plurality of channels within a predetermined frequency band. A transmitting means for transmitting and receiving by using the above, a signal receiving means for receiving an image request signal from a display device via the transmitting means and the modulation / demodulation means of the monitoring device, and for capturing an image of the monitoring area. Image data transmitting means for transmitting the image data captured by the image capturing means to the display device which has transmitted the image request signal received by the signal receiving means via the transmission means and the modulation / demodulation means of the monitoring device. And a transmission channel setting unit for setting a transmission / reception channel by the transmission unit between the display unit and the display device.

According to the first aspect of the present invention, the plurality of display devices and the plurality of monitoring devices each include a transmission unit and a modulation / demodulation unit. The transmission means can divide a predetermined frequency band into a plurality of channels. By using the plurality of divided channels, data can be simultaneously transmitted between the plurality of display devices and the monitoring device. Further, the modulation / demodulation means can modulate / demodulate data to be transmitted / received by a direct spread spectrum method and transmit / receive the data. By using this modulation method, data transmission having characteristics such as confidentiality can be realized. When simultaneously transmitting image data having a large amount of information between a plurality of display devices and a monitoring device using this modulation method, the channel to be used among the plurality of channels divided by the transmission channel setting means is used. Because it is determined, there is no interference. This makes it possible to provide a wireless monitoring system capable of simultaneously transmitting data with a large amount of information between a plurality of display devices and a monitoring device by using a spread spectrum modulation method having various characteristics.

According to a second aspect of the present invention, in the wireless monitoring system according to the first aspect of the present invention, in addition to the configuration of the first aspect, the display device has a voice input unit for inputting voice and an input by voice input unit. Further includes audio data transmitting means for transmitting the audio data to the monitoring device via the transmission means and the modulation / demodulation means of the display device, wherein the monitoring device transmits the audio data transmitted from the display device to the monitoring device. Audio data receiving means for receiving through the transmission means and the modulation / demodulation means, and audio output means for outputting the audio data received by the audio data receiving means.

According to the second aspect of the present invention, it is possible to input a voice such as a warning of a monitor by the voice input means of the display device, and to input the voice data to the monitoring device by the voice data transmitting means. Can be sent.
The transmitted sound data can be received by the sound data receiving means of the monitoring device, and the received sound data can be output to the subject as sound such as a warning by the sound data output means. Thus, a wireless monitoring system capable of transmitting image and audio data can be provided.

According to a third aspect of the present invention, in the wireless monitoring system according to the second aspect of the present invention, in addition to the configuration of the second aspect, the display device transmits the audio data transmitted from the monitoring device to a transmission unit of the display device and The monitoring device further includes audio data receiving means for receiving the audio data via the modulation / demodulation means, and audio output means for outputting the audio data received by the audio data receiving means. And an audio data transmitting unit for transmitting the audio data input by the audio input unit to the display device via the transmission unit and the modulation / demodulation unit of the monitoring device.

[0013] According to the third aspect of the present invention, the voice input means of the monitoring device can input a voice near the monitoring device, and the input voice data can be transmitted to the display device by the voice data transmitting device. be able to. The transmitted audio data can be received by the audio data receiving means of the display device, and the received audio data can be output to the monitor by the audio data output means. Thus, a wireless monitoring system capable of transmitting image and two-way audio data can be provided.

According to a fourth aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the display device further includes channel extracting means for extracting an empty channel, and transmission channel setting means. Includes means for determining a transmission channel based on the result of extraction by the channel extracting means.

According to the invention described in claim 4, the channel extracting means of the display device can extract an unused channel among the plurality of transmission channels. The transmission channel setting means of the monitoring means can determine an empty channel extracted by the channel extraction means as a transmission channel. This makes it possible to provide a wireless monitoring system that does not require a transmission channel to be determined in advance.

According to a fifth aspect of the present invention, there is provided a display device,
A display device for receiving and displaying image data from a monitoring device, comprising: a modulation / demodulation unit for modulating / demodulating data according to a spread spectrum method, and a data unit connected to the modulation / demodulation unit, the data modulated according to the spread spectrum method being a predetermined value. Transmission means for transmitting and receiving using any one of a plurality of channels in a frequency band, signal transmission means for transmitting an image request signal to the monitoring apparatus to the modulation / demodulation means, and transmission means and transmission / reception means Image data receiving means for receiving image data from the monitoring device, and display means for displaying an image received by the receiving means.

According to the fifth aspect of the present invention, the display device includes the transmission means and the modulation / demodulation means. The transmission means can divide a predetermined frequency band into a plurality of channels. By using the plurality of divided channels, a plurality of display devices can simultaneously receive image data. Further, the modulation and demodulation means can modulate the received data by a spread spectrum method and receive the data. By using this modulation method, data transmission having characteristics such as confidentiality can be realized. Also, when a plurality of display devices receive image data with a large amount of information at the same time using this modulation method, interference may be caused by selecting and receiving a channel to be received among a plurality of divided channels. There is no. This makes it possible to provide a display device in which a plurality of display devices can simultaneously receive data with a large amount of information by using the extended spectrum modulation method having various features.

A display device according to a sixth aspect of the present invention comprises:
A display device for receiving and displaying image data from a monitoring device, comprising: a modulation / demodulation unit for modulating / demodulating data according to a spread spectrum method, and a data unit connected to the modulation / demodulation unit, the data modulated according to the spread spectrum method being a predetermined value. Transmitting means for transmitting and receiving using any of a plurality of channels in a frequency band, image data receiving means for receiving image data from the monitoring device via the transmitting means and modulation / demodulation means, and receiving by the receiving means Display means for displaying the resulting image.

According to the invention described in claim 6, the display device includes a transmission unit, a modulation / demodulation unit, an image data reception unit, and a display unit. By selecting a receiving channel among the plurality of channels divided by the transmission unit, image data can be received and displayed on the display unit without transmitting an image request signal. This allows
As long as at least one display device having the signal transmitting means transmits the image request signal, a display device capable of receiving image data can be provided.

A display device according to a seventh aspect of the present invention comprises:
In addition to the configuration of the invention according to claim 5, the display device further includes a voice input unit for inputting voice, and voice data input by the voice input unit to the monitoring device via the transmission unit and the modulation / demodulation unit. Voice data transmitting means for transmitting the data.

According to the seventh aspect of the present invention, it is possible to input a voice such as a warning of a monitor by the voice input means, and to transmit the input voice data to the monitoring device by the voice data transmitting means. Can be. This makes it possible to provide a display device that can receive image data from the monitoring device and transmit audio data input to the monitoring device.

The display device according to the invention described in claim 8 is:
In addition to the configuration of the invention described in claim 5 or 6, the transmission channel setting means includes means for changing the transmission channel according to predetermined conditions.

According to the present invention, the transmission channel changing means changes the channel displayed by the display device according to a predetermined condition. Accordingly, it is possible to provide a display device that can change the transmission channel displayed on the display unit in response to a condition that image data is transmitted on a plurality of transmission channels.

According to a ninth aspect of the present invention, there is provided a monitoring device comprising:
A monitoring device for transmitting captured image data to a display device, comprising: a modulation / demodulation unit for modulating / demodulating data by a spread spectrum method; and a modulation / demodulation unit connected to the modulation / demodulation unit, the data modulated by the spread spectrum method being transmitted to a predetermined frequency. Transmitting means for transmitting and receiving using any of a plurality of channels in the band, signal receiving means for receiving an image request signal from the display device via the transmitting means and the modulation / demodulation means, and Imaging means for taking an image, and image data transmitting means for transmitting, via the transmission means and the modulation / demodulation means, the image data captured by the imaging means to the display device which has transmitted the image request signal received by the signal receiving means. And a transmission channel setting unit for setting a transmission / reception channel by the transmission unit between the transmission unit and the display device.

According to the ninth aspect of the present invention, the monitoring device includes a transmission unit, a modulation / demodulation unit, and a transmission channel setting unit. The transmission means can divide a predetermined frequency band into a plurality of channels. By using the plurality of divided channels, a plurality of monitoring devices can simultaneously transmit image data. In addition, the modulation and demodulation means,
The data to be transmitted can be modulated by the spread spectrum method and transmitted. By using this modulation method, data transmission having characteristics such as confidentiality can be realized. Also, when a plurality of monitoring devices transmit image data with a large amount of information at the same time using this modulation method, the transmission channel setting means determines the channel to be used for transmission among the plurality of divided channels. , Do not interfere. Thus, it is possible to provide a monitoring device that can simultaneously transmit data with a large amount of information by a plurality of monitoring devices by using a spread spectrum modulation method having various characteristics.

According to a tenth aspect of the present invention, in addition to the configuration of the ninth aspect, the monitoring device transmits the audio data transmitted from the display device via a transmission unit and a modulation / demodulation unit. It further includes audio data receiving means for receiving, and audio output means for outputting audio data received by the audio data receiving means.

According to the tenth aspect of the present invention, the transmitted voice data can be received by the voice data receiving means, and the received voice data can be transmitted to the subject as voice such as a warning by the voice data output means. Can be output. Thereby, image data can be transmitted to the display device, and audio data received from the display device can be output.
A monitoring device can be provided.

[0028] In the monitoring apparatus according to the eleventh aspect of the present invention, in addition to the configuration of the ninth aspect, the transmission channel setting means includes means for setting a transmission channel in advance.

According to the eleventh aspect, the transmission channel setting means can set the transmission channel used for transmitting image data from the monitoring device to the monitoring means. This makes it possible to provide a monitoring device capable of presetting an occupied channel.

According to a twelfth aspect of the present invention, in the monitoring device according to the ninth aspect, in addition to the configuration of the ninth aspect, the image data transmitting means transmits the image data captured by the image capturing means.
Means for providing to the modulation and demodulation means for transmission to two or more display devices including the display device which transmitted the image request signal.

According to the twelfth aspect of the present invention, the image data transmitting means transmits the image data to the display device other than the display device which has transmitted the image request signal, using one of the transmission channels. Image data can be received by selecting a transmission channel among display devices that have not transmitted an image request signal. Accordingly, it is possible to provide a monitoring device capable of transmitting image data to another display device only by transmitting at least one of the plurality of display devices transmitting the image request signal.

According to a thirteenth aspect of the present invention, in addition to the configuration of the ninth aspect, the monitoring device further comprises means for displaying image data when a predetermined condition is satisfied. And control means for stopping transmission to the communication device.

According to the thirteenth aspect, the control means can stop the transmission of the image data according to a predetermined condition. Accordingly, it is possible to provide a monitoring device that stops transmission of image data and shifts a transmission channel to an empty channel in response to a condition such as the display device transmitting unnecessary data of image data.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, repetition of detailed description thereof will be appropriately omitted.

Referring to FIG. 1, a monitoring device according to the present invention includes a camera 20 for capturing an image of a monitoring area,
0 for converting the image data into data.
An image compression unit 24 connected to the D conversion unit 22 and the A / D conversion unit 22 for compressing the image data; a memory 26 connected to the image compression unit 24 and storing the image data at the time of compression; A microphone 40 for inputting voice,
A / D / D / A converter 38 and an A / D / D / A converter 38 which are connected to the speaker 42 for outputting sound, the microphone 40 and the speaker 42, and convert sound data into data. , An echo canceller 36 for performing processing for preventing howling and the like, an audio compression / expansion unit 34 connected to the echo canceller 36 for compressing / expanding audio data, an image compression unit 24, and an audio compression unit. CPU (Central Processing) connected to the decompression unit 34
A communication control unit 28 connected to the CPU 32 and controlling communication with the display device;
8 for performing wireless communication with the display device.
F module.

The communication control unit 28 is connected with the image compression unit 24 and the audio compression / decompression unit 34. The CPU 32 has a ROM (Read Only Memory) storing a program and a RAM (Ra) storing intermediate data and the like in a processing step.
ndom Access Memory). The DIP switch 30 is connected to the CPU 32.

The RF module is connected to the communication control unit 28, and is connected to the direct spread spectrum modulation / demodulation unit 44 for spread spectrum modulation / demodulation of data, and is connected to the direct spread spectrum modulation / demodulation unit 44 and communicates with the display device at a predetermined frequency. It includes an RF transmitting unit 46 and an RF receiving unit 48 for transmitting and receiving, and an antenna 50 connected to the RF transmitting unit 46 and the RF receiving unit 48. The camera 20 is provided so that the monitoring area can be imaged in the field of view. Camera 20
Is not limited to a specific one as long as a captured image can be output to the outside. In the present embodiment, the camera 20 outputs the captured image data to the A / D converter 22 in an analog data format.

The A / D converter 22 converts image data input from the camera 20 from analog data to digital data. The A / D converter 22 outputs the converted digital data to the image compressor 24.

The image compression unit 24 uses the memory 26 to compress the image data input from the A / D conversion unit 22 for each frame. The data compression method is not limited to a specific method, but in terms of compression efficiency and the like, JPEG (Joint Photographic Image Coding Expe
(rts Group) method is preferred. The image compression section 24 outputs the compressed image data to the communication control section 28.

The microphone 40 is provided so that sound in the monitoring area can be collected. The microphone 40 outputs the collected voice data to the A / D / D / A converter 38 in an analog data format.

The A / D / D / A converter 38 includes a microphone 40
Is converted from analog data to digital data. The A / D / D / A converter 38 outputs the converted digital data to the echo canceller 36. Further, the A / D / D / A converter 38 converts audio data input from the echo canceller 36 from digital data to analog data. The A / D / D / A converter 38 converts the converted analog data into a speaker 42
Output to

The echo canceller 36 eliminates howling and acoustic echo due to acoustic coupling between the microphone 40 and the speaker 42. The echo canceller 36 converts the voice data subjected to the echo cancellation processing into the voice compression / decompression unit 3.
4 is output. The echo canceller 36 performs the same echo cancellation processing on the audio data input from the audio compression / decompression unit 34 and outputs the same to the A / D / D / A conversion unit 38.

The audio compression / decompression unit 34 compresses audio data input from the echo canceller 36. The data compression method is not limited to a specific one, but may be an ADPCM (Adaptive Differential Pulse Code M).
odulation) system is preferred. The audio compression / decompression unit 34
The compressed audio data is output to the communication control unit 28. The audio compression / decompression unit 34 decompresses the audio data input from the communication control unit 28. The data decompression method is not limited to a specific one, but it must be the same as the data compression method. The audio compression / decompression unit 34
The expanded audio data is output to the echo canceller 36.

The speaker 42 is connected to the A / D / D / A converter 3
The audio data input from 8 is amplified to generate audio in the monitoring area.

The CPU 32 executes a program stored in the ROM, and controls the image compression section 24, the communication control section 28, and the audio compression / decompression section 34.

The communication control unit 28 stores the compressed image data and the compressed audio data in one packet, and adds an error detection code after each data. The communication control unit 28 outputs the packetized data directly to the spread spectrum modulation / demodulation unit 44. In addition, the communication control unit 28 extracts audio data from the packetized data input directly from the spread spectrum modulation / demodulation unit 44. The communication control unit 28 outputs the extracted audio data to the audio compression / decompression unit 34.

The direct spread spectrum modulation / demodulation section 44 performs direct spread spectrum modulation on the data input from the communication control section 28 using a spreading code. The direct spread spectrum modulator / demodulator 44 outputs the modulated signal to the RF transmitter 46. The direct spread spectrum modulation / demodulation unit 44 performs spread spectrum demodulation on the received data input from the RF reception unit 48 using a spread code. The direct spectrum modulation / demodulation unit 44 outputs the demodulated data to the communication control unit 28. Note that the spreading code used for demodulation must be the same as the spreading code used for modulation.

The RF transmitting section 46 further modulates the signal input directly from the spread spectrum modulating / demodulating section 44 with a carrier having a frequency determined by a transmission channel described later. The RF transmitter 46 amplifies the signal modulated by the carrier and outputs the amplified signal to the antenna 50. By the modulation processing in the RF transmission unit 46, the signal subjected to the spread spectrum can be transmitted using a specific communication frequency and a specific band.

The RF receiving section 48 modulates the signal input from the antenna 50 in the reverse manner to the RF transmitting section 46 and outputs the modulated signal directly to the spread spectrum modulation / demodulation section 44.

The dip switch 30 is a switch for determining a transmission channel. Referring to FIG. 3, the transmission channel is defined as ISM (Industrial Scientific and Medica).
l) Frequency band (2471MHz to 2497MHz)
Channels excluding the G channel among the A to G channels divided into channels. The G channel with the highest frequency is used as a control channel for establishing a communication connection. The DIP switch 30 determines any one of the A to F channels for each monitoring device.

Referring to FIG. 2, a display device according to the present invention includes a monitor 60 for displaying a monitoring area, a monitor controller 62 connected to the monitor, and a monitor controller 62 connected to the monitor controller 62 for expanding image data. An image decompression unit 64 for processing, a memory 26 connected to the image decompression unit 64 for storing image data at the time of decompression, a microphone 40 for inputting audio, and a speaker 42 for outputting audio. Connected to the microphone 40 and the speaker 42,
An A / D / D / A converter 38 for converting the audio data, an echo canceller 36 connected to the A / D / D / A converter 38 for performing a process for preventing howling and the like, A CPU 7 connected to the canceller 36 and connected to the image expansion unit 64 and the audio compression and expansion unit 34 for compressing and expanding audio data;
2, a communication control unit 68 connected to the CPU 72 and controlling communication with the monitoring device, and an RF module connected to the communication control unit 68 and performing wireless communication with the monitoring device. The image expansion section 64 and the audio compression / expansion section 34 are connected to the communication control section 68.

As in the case of the CPU 32, the CPU 72
Includes OM and RAM. An operation switch 70 and a display lamp 71 are connected to the CPU 72.

The RF module is an RF module of the above-described monitoring device.
It has the same configuration as the module. 2 will be described below.

The monitor 60 displays an image captured by the camera 20. The monitor 60 is not limited to a specific one as long as it can display an image.

The monitor controller 62 includes the image decompression unit 6
Data conversion (for example, D / A conversion) so that the image data input from
Perform

The image decompression unit 64 uses the memory 26 to decompress the image data input from the communication control unit 68 for each frame. The data decompression method must be the same as the method used for data compression. The image decompression unit 64 outputs the decompressed image data to the monitor controller 62.

The CPU 72 executes a program stored in the ROM, and controls the image decompression unit 64, the communication control unit 68, and the audio compression / decompression unit 34.

The communication control unit 68 extracts image data and audio data from the packetized data input directly from the spread spectrum modulation / demodulation unit 44. The communication control unit 68 outputs the extracted image data to the image decompression unit 64 and the extracted audio data to the audio compression and decompression unit 34.
The communication control unit 68 packetizes the audio data input from the audio compression / decompression unit 34. Since this packetization process is the same as the communication control unit 28 in FIG. The description will not be repeated.

The operation switch 70 is a switch for inputting a transmission channel switching instruction and the like.

The display lamp 71 includes a plurality of lamps for displaying the use status of the transmission channel and the like.

Referring to FIG. 4, communication control unit 2 of the monitoring device
The configuration of a packet in the communication control unit 8 or the communication control unit 68 of the display device will be described. Referring to FIG. 4A, a voice reply packet in communication control unit 68 of the display device includes a header, voice data, and a CRC (Cyclie Reundancy Check code, error detection code). Referring to FIG. 4B, the video / audio transmission packet in communication control unit 28 of the monitoring device includes a header, voice data, CRC for voice data, image data, and CRC for video data. Referring to FIG. 4C, the headers shown in FIGS. 4A and 4B include a preamble, a frame synchronization signal, a call signal, a destination address, a source address, command information, and a CRC for the header. The command information includes an image request command, a transmission channel setting command, and the like. In one transmission channel, the monitoring device transmits image data and audio data, and the display device transmits audio data. Therefore, as shown in FIG. Communication is performed.

Referring to FIGS. 5 to 7, the display device a is composed of two display devices a and b, and three monitoring devices c, d and e. The wireless monitoring system that displays images captured by the monitoring device c and the monitoring device d and displays images captured by the monitoring device e on the display device b operates as follows.

First, in step 2 (hereinafter, step is abbreviated as S), the display device a determines whether or not there is a signal being transmitted on the G channel which is a control channel. If there is a signal being transmitted to the G channel (YES in S2), the process returns to S2, and waits until the G channel becomes empty. On the other hand, if there is no signal being transmitted on the G channel (NO in S2), the process proceeds to S4. S4
, The display device a transmits an image request signal to the monitoring device c using the G channel. At S6, it is determined whether or not monitoring device c is in a standby state. If the transmission channel of the monitoring device c is set to the G channel, it is in a standby state. In other cases, the image data is being transmitted on the A to F channels, and is not in the standby state. If the monitoring device c is not in the standby state in S6 (NO in S6), the process returns to S6, and the monitoring device c
Wait until the state transitions to the standby state. On the other hand, when monitoring device c is in the standby state in S6 (YES in S6), the process proceeds to S8. In S8, monitoring device c transmits an Ack signal to display device a using the G channel. In S10, monitoring device c transmits an image / audio signal to display device a using channel A set by dip switch 30. In S12, the display device a determines whether there is an interrupt signal on the G channel. If there is an interrupt signal on the G channel (Y in S12)
ES), the process is shifted to, an interrupt process is performed, and thereafter, the process is returned. On the other hand, if there is no interrupt signal on the G channel (NO in S12), the process proceeds to S14.
In S14, the display device a performs the same processing as in S4 on the monitoring device d. In S16, the display device a performs the same processing as in S6 on the monitoring device d. In S18, monitoring device d performs the same processing as that of S8 on display device a. In S20, monitoring device d transmits an image / audio signal to display device a using the B channel set by DIP switch 30.

On the other hand, if there is an interrupt signal by the G channel in S12 (YES in S20), referring to S6, in S44, the display device b sends the monitor device e to the monitor device e.
The same processing as in step 4 is performed. In S46, the display device b
The same processing as in S6 is performed on the monitoring device e. S4
At 8, the same processing as at S8 is performed on the monitoring device e and the display device b. In S50, the monitoring device e sets the display device b
Is transmitted using the C channel set by the dip switch 30. Note that S48
After the process of, the process returns to S14 of FIG. 5 and the interrupt process ends.

Referring to FIG. 7, at S22, display device a
It is determined which of the monitoring device c and the monitoring device d is to be displayed. The monitoring device to be displayed is selected by the operation switch 70, and according to the selection, S22
Is determined. At S22, the display device a is replaced by the monitoring device c.
Is selected (c in S22), the process proceeds to S24. On the other hand, when monitoring device d is selected (d in S22), the process proceeds to S28.

In S24, the display device a changes the transmission channel to the A channel. At S26, the display device a
Outputs the image captured by the monitoring device c to the monitor 60, and reproduces the sound collected by the monitoring device c on the speaker 42. Further, in S26, the display device a returns a voice (for example, a warning sound) signal input from the microphone 40 of the display device to the monitoring device c using the A channel. The returned voice is the speaker 4 of the monitoring device c.
2 output.

In S28, the display device a performs the same processing as in S24 on the monitoring device d. In S30, the display device a sends a signal to the monitoring device d using the B channel.
The same processing as in step 26 is performed.

At S32, the operation switch 7 is displayed on the display device a.
From 0, it is determined whether any of monitoring end and monitoring device change has been input. At S32, the display device a
If the monitoring end request has been input (end in S32), the process ends. On the other hand, at S32, the display device a
If the monitoring device change request has been input (changed in S32), the process returns to S22. In S22, when another monitoring device is selected, an image captured by another monitoring device can be immediately output without transmitting an image request signal or an Ack signal.

On the other hand, referring to FIG. 6, in S52, the display device “b” instructs the monitoring device “e” by using the C channel in S2.
The same processing as in step 6 is performed. In S54, it is determined whether or not the end of monitoring has been input from operation switch 70 to display device b. In S54, if a monitoring end request has been input to display device b (YES in S54), the process ends. On the other hand, if the monitoring end request has not been input to the display device b in S54 (NO in S54), the process proceeds to S5.
Returned to 2.

The operation of the wireless monitoring system based on the above structure and flowchart will be described.

Referring to FIG. 8, black circles indicate signal transmission sources, and arrows indicate signal transmission destinations. Reference numerals in parentheses provided on the left and right margins indicate step numbers in FIGS.

When a signal for selecting the monitoring device c and the monitoring device d is input from the operation switch 70 of the display device a, the display device a uses the G channel as a control channel at S4. An image request signal 100 is transmitted to the monitoring device c. In S8, the monitoring device c having received the image request signal uses the G channel to output the Ack signal 102
Send In S10, monitoring device c transmits image / audio signal 104 to display device a using channel A in accordance with the transmission channel setting instruction input from dip switch 30. On the other hand, at S14, the display device a
Sends an image request signal 1 to the monitoring device d using the G channel.
06 is transmitted. In S18, the monitoring device d that has received the image request signal uses the G channel to output the Ack signal 108.
Send In S20, monitoring device d transmits image / audio signal 106 to display device a using B channel in accordance with the transmission channel setting instruction input from DIP switch 30.

The display device b is operated by the operation switch 70.
When an input for selecting the monitoring device e is input, an image request signal 116 is transmitted from the display device b to the monitoring device e using the G channel in S44, and in S46, the monitoring device e transmits to the display device b. Ack signal 118 using G channel
Is transmitted, and in S52, the display device b is
The video / audio signal 120 is transmitted using the C channel.

When the monitoring device c is selected on the display device a, an audio signal 112 is transmitted from the display device a to the monitoring device c using the A channel in S26, and two-way communication is performed. When the monitoring device d is selected on the display device a, the audio signal 114 is transmitted from the display device a to the monitoring device d using the B channel in S30. Also, S5
At 2, the audio signal 122 is transmitted from the display device b to the monitoring device e using the C channel.

As described above, the wireless monitoring system, the display device, and the monitoring device according to the embodiment of the present invention can have a plurality of transmission channels, and can simultaneously transmit data between the plurality of display devices and the monitoring device. Can be transmitted and received. Further, since the direct spread spectrum method is used as the data modulation method, image data with a large amount of information can be transmitted at high speed while maintaining features such as confidentiality, and no interference occurs. As described above, it is possible to provide a wireless monitoring system, a display device, and a monitoring device capable of simultaneously and accurately communicating data with a large amount of information among a plurality of devices.

Next, a modified example of the embodiment of the present invention will be described. <First Modified Example> Referring to FIG. 9, a first modified example is obtained by adding a channel setting signal to an image request signal transmitted from a display device to a monitoring device (signal 130, signal 132, and signal 132). Signal 134).

The display device executes the program stored in the ROM of the CPU 32 to extract an empty channel among the transmission channels before transmitting the image request signal. For example, carrier sense for detecting whether or not a data packet is being transmitted to each transmission channel is executed, and an empty channel is extracted. The display device designates one of the extracted empty channels as a transmission channel, and transmits it to the monitoring device together with the image request signal.

According to this modification, it is not necessary to set a transmission channel in the monitoring device in advance.

<Second Modification> Referring to FIG.
In the modified example, the image / audio signal transmitted from the monitoring device is also transmitted to a display device other than the display device from which the image request signal is transmitted (signal 140, signal 142, and signal 142).
Signal 144).

When transmitting the video / audio signal, the monitoring device specifies a global address including the addresses of all the display devices in the destination address shown in FIG. 4C.

According to this modified example, the display device b includes the monitoring device c and the monitoring device d that have not transmitted the image request signal.
, The video and audio signal 140 from the monitoring device c and the video and audio signal 142 from the monitoring device d can be received. As a result, the display device b can display the image and sound of the monitoring device that has not transmitted the image request signal only by switching the transmission channel with the operation switch 70.

<Third Modification> Referring to FIG.
In the modified example, in addition to the second modified example, a sub-display device dedicated to reception is provided, and an image and sound signal is received from each monitoring device (signal 150, signal 152, signal 1).
54).

According to this modification, the sub-display device does not require a structure for transmitting the image request signal and the audio signal. This makes it possible to realize an inexpensive sub-display device that can display images and sounds of all monitoring devices simply by switching the transmission switch with the operation switch 70.

<Fourth Modification> Referring to FIG.
In the modified example, in addition to the second modified example, an image end signal is added to the audio signal from the display device to the monitoring device (signal 160, signal 162, signal 164).

The display device is operated when the operation switch 70 receives an input for selecting the end of monitoring, or when the microphone 4
When there is no audio input for a certain period of time from 0, an image end signal is transmitted to the monitoring device together with audio data. The monitoring device that has received the image end signal ends the image / audio output, changes the set channel from the transmission channel to the control channel (G channel), and shifts to a standby state.

According to this modification, unnecessary transmission of an image / audio signal can be reduced, and more vacant channels can be provided as transmission channels.

<Fifth Modification> Referring to FIG.
Is a display device provided with a monitor scan function.

In the display device a, when an image / audio signal is received on the A channel from the monitoring device c, on the B channel from the monitoring device d, and on the C channel from the monitoring device e, the monitor scanning function is as follows. Works like Referring to FIG. 13, in S50, an initially set channel is set. At S52, the state of operation switch 70 is read. In S54, it is determined whether or not the scan mode is selected from the read operation switch 70.
If it is determined in S54 that the scan mode is set (YES in S54), the process proceeds to S58. On the other hand, if it is determined in S54 that the scan mode has not been set (NO in S54), the process proceeds to S56.
(Fixed mode). In S56, it is determined whether to change the monitoring device. If the monitoring device is changed in S56 (YES in S56), the process proceeds to S60. On the other hand, if the monitoring device is not changed in S56 (NO in S56), the process returns to S52. S5
At 8, it is determined by a timer provided in the CPU 72 whether or not the reception state of the displayed monitoring device has passed 10 seconds. If the time is up in S58 (YES in S58), the process proceeds to S60. On the other hand, S58
If the time is not up (N at S58)
O), the process is moved to S62. At S60, S50
The channel is changed from the channel set in to another channel. In S62, the display device receives the image / audio data using the changed channel. In S64, the display device transmits the audio data. In S66, the display device expands the image / audio data. At S68,
The display device displays an image and outputs sound.

According to the present modification, referring to FIG. 14, the screen of monitor 60 on the display device can be automatically switched.

<Sixth Modification> Referring to FIG.
In the modified example, the monitoring apparatus is provided with an image transmission end function.

In S70, when the monitoring device receives the image request signal (YES in S70), the monitoring device sets a transmission channel in S72. In S74 to S78, the image / audio data is transmitted by the display device that has transmitted the image request signal. In S80, a timer provided in CPU 32 determines whether or not 10 minutes have continuously passed. If time is up in S80 (YE in S80
S), the process is moved to S82. On the other hand, if the time has not elapsed in S80 (NO in S80), the process returns to S74. In S80, the monitoring device ends the transmission of the image / audio data, changes the setting channel from the transmission channel to the control channel (G channel), and shifts to a standby state.

According to this modification, unnecessary transmission of an image / audio signal can be reduced, and more vacant channels can be provided as transmission channels.

<Seventh Modification> Referring to FIG.
Is a display device provided with a data transmission status display function of a transmission channel. The display device detects the use status of each channel by checking whether or not to receive a packet within a predetermined time in the transmission channels except before and after the change at the timing of changing the transmission channel. In this modification, since it takes time to determine whether to receive a packet, detection is performed only when five minutes or more have elapsed since the transmission channel was changed. Further, the transmission channels are divided into upper (A, B, and C channels) and lower (D, E, and F channels) and are detected alternately.

Referring to FIG. 16, in S100, CPU
A timer provided in 72 determines whether five minutes have elapsed since the previous channel change. If the time has not elapsed in S100 (NO in S100), this processing ends without doing anything. On the other hand, if the time has elapsed in S100 (YES in S100), the process proceeds to S102. In S102, since it is not necessary to detect the channel before the change and the channel after the change, the channels before and after the change are stored in order to exclude these channels from the detection targets. In step S104, it is determined whether the lower channel has been detected in the previous detection process in order to separate the upper channel and the lower channel and perform the processing alternately. S104
If the lower channel was the target last time (S1
04, NO), and this time the target is the upper channel (S
108), in S104, if the lower channel was previously the target (YES in S104), the current target is the lower channel (S106). In S110, since it is not necessary for the display device itself to detect the transmission channel used by the monitoring device that has transmitted the image request signal, a determination is made to exclude this channel from the detection target. In S112, it is detected whether or not a packet is received within a predetermined time on the detection target channel. S
At 114, according to the detection result, referring to FIG. 17, the display lamp 71 corresponding to the channel where the packet is detected is turned on, and the display lamp 71 corresponding to the channel where the packet is not detected is turned off. In S116, it is determined whether or not detection has been performed for all of the detection target channels. If it is determined in S116 that the detection of all the channels to be detected has not been completed (NO in S116),
The process returns to S104. On the other hand, if it is determined in S116 that detection of all channels to be detected has been completed (YES in S116), the process proceeds to S118. In S118, the detected result is set in the storage channel. The content set in the storage channel is used to display the status of a channel that was not detected at the time of detection on the display lamp 71.

According to the present modification, the status of data transmission from the monitoring device whose image has been requested by another display device can be visually grasped on the display device, and the transmission channel can be selected without selecting an empty channel. it can.

As described above, the same operation and effect as those of the present embodiment can be exhibited in the modification of the present embodiment.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Brief description of the drawings]

FIG. 1 is an electrical control block diagram of a monitoring device according to an embodiment of the present invention.

FIG. 2 is an electrical control block diagram of the display device according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram of a transmission channel.

FIG. 4 is a configuration diagram of a communication packet.

FIG. 5 is a flowchart 1 showing a procedure of data transmission between the monitoring device and the display device.

FIG. 6 is a flowchart 2 showing a procedure of data transmission between the monitoring device and the display device.

FIG. 7 is a flowchart 3 showing a procedure of data transmission between the monitoring device and the display device.

FIG. 8 is an explanatory diagram of a data transmission procedure between the monitoring device and the display device.

FIG. 9 is an explanatory diagram of a data transmission procedure between the monitoring device and the display device.

FIG. 10 is an explanatory diagram of a data transmission procedure between the monitoring device and the display device.

FIG. 11 is an explanatory diagram of a data transmission procedure between the monitoring device and the display device.

FIG. 12 is an explanatory diagram of a data transmission procedure between the monitoring device and the display device.

FIG. 13 is a flowchart illustrating a procedure of data reception of the display device.

FIG. 14 is a diagram illustrating a display screen of a display device.

FIG. 15 is a flowchart illustrating a procedure of data transmission of the monitoring device.

FIG. 16 is a flowchart illustrating a procedure of data reception of the display device.

FIG. 17 is an external view of a display device.

[Explanation of symbols]

Reference Signs List 20 camera, 22 A / D conversion unit, 24 image compression unit, 26 memory, 28,68 communication control unit, 30 dip switch, 32,72 CPU, 34 audio compression / decompression unit, 36 echo canceller, 38 A / D / D /
A conversion unit, 40 microphones, 42 speakers, 44 direct spread spectrum modulation / demodulation unit, 46 RF transmission unit, 48 R
F receiving unit, 50 antennas, 60 monitors, 62 monitor controllers, 64 image decompression units, 70 operation switches, 71 display lamps.

Claims (13)

[Claims] 1. A wireless monitoring system including a plurality of display devices and a plurality of monitoring devices, wherein each of the display devices is connected to the modulation and demodulation means for modulating and demodulating data by a spread spectrum method. Transmission means for transmitting and receiving data modulated by the spread spectrum method using any of a plurality of channels in a predetermined frequency band, and an image request signal to the monitoring device, the modulation and demodulation means Signal transmitting means for giving and transmitting; image data receiving means for receiving image data from the monitoring device via the transmitting means and the modem means; and displaying an image received by the receiving means. Display means, wherein each of the monitoring devices includes: a modulation / demodulation means for modulating / demodulating data by a spread spectrum method; A transmission unit connected to the modulation / demodulation unit of the device, for transmitting and receiving data modulated by the spread spectrum method using any one of a plurality of channels in a predetermined frequency band; and the transmission unit of the monitoring device And a signal receiving unit for receiving an image request signal from the display device via the modulation / demodulation unit; an imaging unit for capturing an image of a monitoring area; and image data captured by the imaging unit. The display device that has transmitted the image request signal received by the signal receiving unit, the image data transmitting unit for transmitting via the transmission unit and the modulation and demodulation unit of the monitoring device, between the display device, A transmission channel setting unit for setting a transmission / reception channel by the transmission unit. 2. The display device, comprising: a voice input unit for inputting a voice; and voice data input by the voice input unit, the monitoring device transmitting the transmission unit and the modulation / demodulation unit of the display device. Audio data transmitting means for transmitting the audio data via the transmission device and the modulation / demodulation means of the monitoring device. The wireless monitoring system according to claim 1, further comprising: a data receiving unit; and an audio output unit for outputting audio data received by the audio data receiving unit. 3. The audio data receiving means for receiving the audio data transmitted from the monitoring device via the transmission means and the modulation / demodulation means of the display device, and the audio data receiving means. Further comprising audio output means for outputting audio data received by the, the monitoring device, audio input means for inputting audio, audio data input by the audio input means, the display device, 3. The wireless monitoring system according to claim 2, further comprising an audio data transmitting unit for transmitting via said transmitting unit and said modem unit of said monitoring device. 4. The display device further includes channel extracting means for extracting an empty channel, and the transmission channel setting means includes means for determining a transmission channel based on a result of the extraction by the channel extracting means. The wireless monitoring system according to claim 1. 5. A display device for receiving and displaying image data from a monitoring device, comprising: a modulation / demodulation unit for modulating / demodulating data by a spread spectrum system; and a modulation / demodulation unit connected to the modulation / demodulation unit and modulated by a spread spectrum system. A transmission unit for transmitting and receiving data using any of a plurality of channels in a predetermined frequency band, and a signal transmission unit for transmitting an image request signal to the monitoring device by giving the image request signal to the modulation and demodulation unit. A display device comprising: image data receiving means for receiving image data from the monitoring device via the transmission means and the modulation / demodulation means; and display means for displaying an image received by the receiving means. 6. A display device for receiving and displaying image data from a monitoring device, comprising: a modulation / demodulation unit for modulating / demodulating data by a spread spectrum system; and a modulation / demodulation unit connected to the modulation / demodulation unit and modulated by a spread spectrum system. A transmission unit for transmitting and receiving data using any one of a plurality of channels within a predetermined frequency band; and an image for receiving image data from the monitoring device via the transmission unit and the modulation / demodulation unit. A display device, comprising: a data receiving unit; and a display unit for displaying an image received by the receiving unit. 7. The display device transmits voice data input by the voice input device and voice data input by the voice input device to the monitoring device via the transmission device and the modulation / demodulation device. The display device according to claim 5, further comprising: a voice data transmitting unit for transmitting the voice data. 8. The display device according to claim 5, wherein the transmission channel setting unit includes a unit for changing a transmission channel according to a predetermined condition. 9. A monitoring device for transmitting captured image data to a display device, comprising: a modulating / demodulating means for modulating / demodulating data by a spread spectrum method; and a modulating / demodulating means connected to the modulating / demodulating means for transmitting data modulated by a spread spectrum method. A transmission unit for transmitting and receiving using any one of a plurality of channels in a predetermined frequency band; and a signal reception for receiving an image request signal from the display device via the transmission unit and the modulation / demodulation unit. Means, an image pickup means for picking up an image of a monitoring area, image data picked up by the image pickup means, to a display device which has transmitted an image request signal received by the signal receiving means, to the transmission means and the modem. Transmission / reception channel by the transmission means between the image data transmission means for transmitting via the means and the display device And a transmission channel setting means for setting, monitoring device. 10. An audio data receiving unit for receiving audio data transmitted from the display device via the transmission unit and the modulation / demodulation unit, and the audio data received by the audio data receiving unit. The monitoring device according to claim 9, further comprising: an audio output unit configured to output a sound signal. 11. The monitoring apparatus according to claim 9, wherein said transmission channel setting means includes means for setting a transmission channel in advance. 12. The image data transmitting means for providing the image data captured by the image capturing means to the modulation / demodulation means in order to transmit the image data to two or more display devices including a display device which has transmitted an image request signal. 10. The method of claim 9, comprising means.
The monitoring device according to claim 1. 13. The monitoring device according to claim 9, wherein the monitoring device further includes a control unit that stops transmitting the image data to a display unit when a predetermined condition is satisfied.