JPH0246148Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a still image display device in a still image transmission system.

In general, standard television transmission methods:
Since 60 screens (fields) are continuously transmitted per second, moving images can be reproduced as they are. For example, as shown in FIG. 1, a TV camera 1 and a monitor 3 are connected by a coaxial cable 2,
An image signal obtained by a television camera 1 is sent to a monitor 3. Since the transmission using the coaxial cable 2 has a transmission bandwidth of 4 to 6 MHz, moving images can be reproduced as they are. However, this method is not suitable for long-distance transmission due to cost and other reasons.

Therefore, the idea was to transmit still images instead of moving images. In other words, transmission is performed in the telephone band (0.3 to 3.4 KHz) using a narrowband transmission line (hereinafter referred to as a transmission line) such as a telephone line.
This method will be explained with reference to FIG. A television camera 4 and a transmitting side memory (hereinafter referred to as TX memory) 5 are provided in a transmitting system 100. The receiving system 200 is provided with a receiving side memory (hereinafter referred to as RX memory) 7 and a monitor 8. The TX memory 5 of the transmitting system 100 and the RX memory 7 on the receiving side are connected by a transmission line 6. The image signal obtained by the television camera 4 is stored in the single-band TX memory 5 at a standard television system speed, and read out from the TX memory 5 at a speed matching the band of the transmission path 6.
The image signal read out in this way is transmitted to the transmission line 6.
The data is stored in the RX memory 7 via the RX memory 7. Furthermore, RX
The image signal stored in the memory 7 is read out again at the standard television system speed and output to the monitor 8. This reading is performed with a constant refresh cycle.

In this way, the still image transmission method requires only a narrow transmission bandwidth, so a long transmission distance can be achieved. On the other hand,
The transmission speed of the image (one field) must be considerably slowed down. The aforementioned transmission line (0.3~3.4KHz)
According to the data transmission time for an image (1 field) is approximately 30
It takes seconds.

As described above, since still image transmission takes time, the interval at which data in the RX memory 7 is rewritten becomes long. Since still image transmission is normally used for managing water levels in dams and other matters, it is difficult to detect changes in images sent from the same location or several locations over time. For example, if a screen at monitoring location B is sent next to a screen at monitoring location A, it is difficult to notice the change in the screen if both points A and B show the same subject. Furthermore, even if the user notices a change in the screen, it is better to be able to recognize that there is a change in the screen due to the transition from the previous screen to the new screen.

The present invention was made based on such a request. Therefore, an object of the present invention is to provide a still image display device that generates sound at each timing when an image signal is transmitted, thereby notifying a monitor of changes in the screen.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 3 is a block diagram of an embodiment of the present invention.
In the figure, 9a, 9b, 9c, and 9d indicate television cameras. This TV camera 9a, 9b, 9
c and 9d are, for example, monitoring locations point a, b, and c.
Assume that it is installed at point and point d. These television cameras 9a, 9b, 9c, and 9d are connected to a TX memory 11 via a switching circuit 10,
By controlling the switching circuit 10 by a control circuit (not shown), for example, the television cameras 9a, 9b,
An image signal from either 9c or 9d is stored in the TX memory 11 at the standard television system speed. this
A signal from the TX memory 11 is transmitted to the RX memory 13 via a transmission line 12. RX memory 1
3 is connected to a monitor 15, and is configured to provide the stored image signal to the monitor 15 via a transmission line at a predetermined refresh cycle.

Furthermore, in the present invention, there is one on the receiving side of the transmission line 12.
Detection means 16 is provided for detecting the synchronization signal at the beginning of the field data. This detection means 16
In the image signal sent from the TX memory 11 to the RX memory 13, in addition to the pure image signal, there is a synchronization signal (timing pulse) that indicates the start of one field data. It is something to detect. After this synchronization signal is taken in, other data, such as image signals, are not allowed to pass through. That is, it is sufficient to extract only the synchronization signal using a circuit equivalent to a filter.

A sounding means 14 is connected to this detecting means 16 . The sounding means 14 includes a signal shaping circuit 17, an audio signal oscillation circuit 18, an amplifier 19, and a sounding medium (hereinafter referred to as a sounding body) 20 such as a speaker. The signal shaping circuit 17 is a circuit that shapes the waveform of the signal obtained by the detection means 16. The audio signal oscillation circuit 18 oscillates for a certain period of time (for example, 0.5 seconds) using the output of the signal shaping circuit 17 as a trigger.
This audio signal is output to 9. The audio signal is amplified by an amplifier 19 and given to a sounding body 20, whereby the sounding body 20 produces a sound such as "pitu". In other words, if one field of image signal is transmitted to the RX memory 13 once every 30 seconds, for example, as described above, then approximately
A sound is made once every 30 seconds.

As explained above, according to the present invention, a wake-up sound is generated in a still image transmission system, so the observer does not have to look closely at the screen, and can clearly hear the image. You can see the change. Therefore, the psychological burden on the supervisor is considerably reduced, and the system is easy to use.

Incidentally, the detection means 16, which is an additional circuit according to the present invention,
Since the sound generation means 14 is small in terms of hardware, it may be incorporated as an RX memory device. Further, the sound generating means 14 may be incorporated into the monitor 15.

[Brief explanation of the drawing]

Figure 1 is a block diagram for explaining the standard television transmission system, Figure 2 is a block diagram of a conventional example, and Figure 3 is a block diagram for explaining the standard television transmission system.
The figure is a block diagram of an embodiment of the present invention. 9a, 9b, 9c, 9d...TV camera, 1
0...Switching circuit, 11...Sending side memory, 12...
...Transmission path, 13...Reception side memory, 14...Sound generation means, 15...Monitor, 16...Detection means.

Claims (1)

[Scope of utility model registration request] An image signal that is transmitted in a still image display device of a still image transmission system that stores an image signal obtained from a television camera in the memory of the transmitting side and then transmits it, and then stores it in the memory of the receiving side and displays it on the monitor. A stationary device characterized in that it is provided with means for detecting a synchronization signal indicating the start of one field data in the middle, and a sounding means for generating a sound at each timing when an image signal is transmitted based on the output of the detecting means. image display device.