JPS5992687A - Still picture transmitter - Google Patents

Abstract

PURPOSE:To obtain a still picture transmitter which is utilized for mutual transmission and enables an instantaneous or sequential switching system by providing plural memories and switches on a transmission side. CONSTITUTION:A video signal inputted from a terminal 31 is A/D-converted and written in a memory 15 or 16 selectively through a switch 14, and one-field or one-frame contents are stored therein. The stored picture information is read out at a speed low allowable for transmission to be transmitted through a switch 17 and a transmission control part 20, and also read at a speed fast enough for a television monitoring to be output to a television monitor through switches 18 and 19. The switches 18 and 19 is operated to display a transmit picture and an already transmitted picture on the same television monitor all the time. Therefore, the switch 17 is changed over by transmission or reception to allow transmission control parts 20 and 30 to have bidirectivity, so that the television monitor a terminal 33 only displays a receive picture.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a still image transmission device that transmits image information such as television signals and character information via a narrowband transmission path.

Conventionally, this type of instantaneous switching type still image transmission apparatus has only one set of storage devices (hereinafter referred to as memory) on the transmitting side, so that only the transmitted image can be viewed. On the other hand, if multiple sets of memories are simply provided as shown in FIG. Since both types of information are sent out, the two images are not alternately exchanged on each TV monitor, making it difficult to use for mutual transmission for conferences and the like.

An object of the present invention is to provide a still image transmission device that eliminates the drawbacks of the conventional method by having multiple sets of memories and switching devices on the transmitting side, can also be used for mutual transmission, and is capable of instantaneous switching or sequential switching. It is to provide.

In the present invention, the transmitting side also includes a plurality of sets of memories,
The receiving side has means for writing the image information transmitted from the transmitting side into any memory among the plurality of memory sets, and a TV monitor. By having a means that allows high-speed reading to be performed on any memory or all memories for display on both terminals, it is possible not only to realize an instantaneous switching method for mutual transmission, which was previously impossible, but also to enable high-speed reading from any memory or all memories. A still image transmitting device having a completely new function is obtained in which a new image can be transmitted to another memory while viewing the same screen, and the screen being transmitted can also be viewed at the same time.

Next, the present invention will be described in detail with reference to the drawings of an embodiment of the present invention. FIG. 2 shows an embodiment of the present invention, in which the sending side has two sets of memo') $1 and $2'e, and a switch for arbitrarily switching between memory writing and reading. have. The video signal input from terminal 31 is A
The /D converter 13 converts the analog signal into a digital signal. The converted digital signal is written to the #11 memory 15 and #2 memory 16 by the switch 14,
Here, the contents of one field or one frame are accumulated. The accumulated image information is read out at a low speed that can be transmitted over a narrowband transmission path, and is sent to the transmission control unit 2 via the switch 17.
0, the parallel data is converted into serial data, a transmission control code is added thereto, and then sent out to the transmission path via the modem connected to the terminal 34.

On the other hand, the transmission image information stored in #1 memory 15 is T
The signal is read out at a fast speed that can be displayed on a V monitor, is demodulated into the original analog signal by a D/A converter 21 via a switch 18, and is output to a TV monitor connected to a terminal 32. In addition, the already transmitted image information stored in #2 memory 16 is read out at a fast speed that can be displayed on a TV monitor, demodulated into the original analog signal by D/A converter 22 via switch 191r, and connected to terminal 33. Other TVs that will be played
Output to monitor. When one screen of information has been sent and the switch 14, 17, 18, 19 is switched, the image information to be transmitted is written into the #2 memory 16. However, the contents of #2 memory (transmitted image) are displayed on the TV monitor connected to 32 via the switch 18, and
# to the TV monitor connected to #3 via the switch 19'
1 The contents of the memory (already transmitted surface image) are displayed.

Therefore, by operating the switch 18, 19, the transmitted image and the previously transmitted image are always displayed on the same TV monitor. Also, switch switches 14 and 18 to the #1 memory side.
If the transmission controllers 20 and 23 are made bidirectional, the TV monitor at the terminal 32 can display only the transmitted image, and the TV monitor at the terminal 33 can display only the received image. I will try my best to do it. The above is the operation of the transmitting unit. While transmitting the newly written image to the receiving side, it is displayed on the TV monitor, and the image previously written to the memory on the other side is displayed on the other TV monitor at the same time. It is possible to display it on a monitor.

Next, to explain the receiving section, the image information transmitted from the transmitting side via the modem connected to the terminal 35 is decoded by the transmission control section 23, and the control code is decoded and converted from real data to parallel data. #1 memory 25 or #2 through the switch 24
Written to memory 26. Which memory to write to can be done by automatically controlling the switch 24 using the control code decoded by the transmission control unit 23, or it can be changed manually depending on the situation. Switcher 2
7.28 is TV from #1 memory 25 or #2 memory 26
The data read out at the rate is supplied to switching D/A converters 29 and 30 automatically or manually. The D/A converter 29.30 demodulates the digital signal to the original analog signal and outputs it to the TV monitor connected to the terminal 36.37.
On the receiving side, as well as on the transmitting side, images being received and images already received can be displayed simultaneously on a fixed TV monitor.

As described above, according to the present invention, not only can images that have already been transmitted and images that are being transmitted be displayed separately on two television monitors, but also the two television monitors can be displayed separately for images that are being transmitted, by operating a switch.

It can also be used for received images, allowing for smooth proceedings in meetings. In this embodiment, the functions have been described with distinction between the transmitting side and the receiving side for ease of explanation, but it is clear that if the receiving side has the same configuration as the transmitting side, the same functions can be performed in both directions.

As explained above, by providing multiple sets of memories on the transmitting side and the receiving side, the present invention eliminates idle time on the transmission line, makes effective use of multiple sets of television monitors, and allows meetings to proceed smoothly. An effective still image transmission device can be realized.

[Brief explanation of drawings]

Figure 1 is a block diagram showing an example of the conventional technology;
The figure is a block diagram showing one embodiment of the present invention. In the figure, 1, 13...A/D converter, 3, 4,
15゜16.25.26...Memory, 6,7,
21, 22.29゜30...D/A converter, 8
, 20, 23...transmission control section, 7, 5, 1
4, 17, 18, 19, 24.27.28...
Switch, 9, 10, 11, 12, 31, 34, 35, 3
6.37...Terminal.

Claims (1)

[Claims] an A/D converter that converts an image signal into a digital signal; two memories that store the image signal converted into a digital signal; and an output of the A/D converter that is selectively stored in the two memories. a first switch for distributing, a second switch for selectively receiving the low-speed digital image signals read from the two memories, and a digital image signal from the second switch as a still image. comprising a transmission means for transmitting, and two third switching devices for complementary selecting the image signals of the television scanning speed read from the two memories,
A still image transmission device characterized in that the image signal being transmitted and the image signal of the transmission stream are extracted from the two third switching devices as monitor signals.