JPS622753B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a still image transmission device that performs image transmission and remote control of a transmitter via a two-wire single line.

In still image transmission, the entire transmission line band is used to send one image quickly, so it is impossible to send different signals on the same line. Conventionally, four wires were used to control the transmitter. The uplink was used for image transmission, and the downlink was used for control signal transmission. Therefore, there was a drawback that the line cost increased.

The present invention is characterized in that an image transmission end signal is encoded and transmitted during a period in which an image synchronization signal or an address signal is transmitted, and based on this, image transmission and control signal transmission are time-divisionally controlled. The purpose of this method is to perform image transmission and remote control of the transmitter using a two-wire line.

FIG. 1 shows an embodiment of the present invention, in which 1 is a still image transmitter, 2 is a still image output signal, 3 is an image transmission end signal, 4 is a line control circuit 1, 5 is a line control signal, 6
is a line switch, 7 is a control reception signal, 8 is a control reception signal detector, 9 is a control reception signal detection output, 10 is a first delay shaping circuit, 11 is an image transmission start signal,
12 is a second delay shaping circuit, 13 is a control signal receiver, 14 is a control output signal latch circuit, 15 is a control output terminal, 16 is a transmission line, 17 is a line switch, 1
8 is a still image reception signal, 19 is a still image receiver, 20
is the reception output of the image transmission end signal, 21 is the line control circuit 2, 22 is the line control signal, 23 is the control signal transmitter output, 24 is the control signal transmitter, 25 is the image reception signal detection circuit, 26 is the image reception signal This is the detection output.

Next, this operation will be explained.

First, when the transmission of one image is completed, the still image transmitter 1 encodes and transmits an image transmission end signal during the period of transmitting the synchronization signal or address signal of the still image output signal 2, and also sends the image transmission end signal 3.
is supplied to the line control circuit 4. In response to the image transmission end signal, the line control circuit controls the line switching device 6 using the line control signal 5, switches the line to the control signal receiver side, and receives the control signal. A control reception signal detector 8 detects the control reception signal 7, and outputs a control reception signal detection output 9 while the carrier wave is being received. At the edge where the control reception signal detection output turns OFF, the line control signal 5 is inverted and the line is switched to the still image transmitter side. On the other hand, the delay shaping circuit 10
Then, at the edge of the OFF edge of the control reception signal detection output, an image transmission start signal 11 with a timing slightly delayed in time is generated to control the startup of the still image transmitter 1, and in addition to the delay shaping circuit 12, the image transmission start signal 11 is generated with a timing slightly delayed in time. A control signal latch timing pulse is generated that is delayed by one field or one frame of the TV signal or more from the start signal. The control signal receiver 13 demodulates and stores the symbols received in a short time and outputs them to the control signal latch circuit 14. A control output terminal of the latch circuit is connected to a control terminal on the camera side (not shown). This latch circuit latches the control signal using the outputs of the 12 delay shaping circuits and outputs it to the control signal output terminal 15, so that control is performed using the image transmission time.

Next, the image signal transmitted via the transmission path 16 is connected to the still image receiver 19 side by a line switch 17, and when the image transmission is completed, an image transmission end signal reception output 20 is supplied to the line control circuit 21. Then, the line control signal 22 is inverted, and the line switching device 17 switches the line to the control signal transmitter 24 side for a short time (time enough for the receiver to verify demodulation), and during this time, the control signal transmitter 24 transfers the control signal to the transmission path. 16 to the sending side. Thereafter, the line control circuit 21 inverts the line control signal again, and the line switch 17 switches the line to the still image receiver side.

The presence or absence of the still image reception signal 18 is detected in the image reception signal detection circuit 25 and the image reception signal detection output 26 is supplied to the line control circuit 21. If a received signal cannot be obtained, the line control signal is inverted and the control signal is retransmitted.

In this way, image transmission and control signal transmission are carried out through the transmission line 16.
A two-wire line can be used by sharing and time-sharing.

Also, the control signal transmission time is at a transmission rate of 200 bits/
Even if signal transmission takes about seconds, it is sufficient to transmit signals within several seconds, so the image update time is only slightly extended.

As described above, according to the present invention, image transmission and remote control can be performed using a two-wire line with almost no change in image transmission time, which reduces line costs and is highly effective in practical use.

[Brief explanation of the drawing]

The figure shows an embodiment of the invention. 1: still image transmitter, 6: line switch, 13: control signal receiver, 16: transmission line, 19: still image receiver, 24: control signal transmitter.

Claims (1)

[Claims] 1. A narrowband still image transmission device having a still image transmitter, a control signal receiver, and a line controller on the transmitting side,
The receiving side has a still image receiver, a control signal transmitter, and a line controller, and every time one image is transmitted from the transmitting side, the image transmission ends during the period when the image synchronization signal or address signal is transmitted. After encoding and transmitting the indicated signal, the transmitting side switches the line to the control signal receiver side, and after storing the control signal, detects the end of the control signal transmission and switches the line to the still image transmitting side, On the receiving side, this still image transmission device has the function of switching the line to the control signal transmitter side upon receiving the image signal transmission end signal, and then switching the line to the still image receiver side after transmitting the control signal for a short time.