JPH02218279A - Image transmission device between digital TV receivers - Google Patents

Abstract

PURPOSE:To send a still picture between digital TV receivers through the use of a general-purpose telephone line network by sending a picture data written in a picture memory of a digital TV receiver for picture transmission to a digital TV receiver for picture reception via a transmission line, writing the data in a built in picture memory and displaying it on a monitor. CONSTITUTION:The write to a picture memory 21 is stopped by a memory controller 22 at a digital TV receiver for picture transmission, the readout from the picture memory 21 is repeated and the picture data read from the picture memory 21 is converted into a serial data by a P/S conversion circuit 28, modulated with a prescribed analog signal at a modulator 31 of a MODEM 30 and the result is outputted to a transmission line 40 via an NCU 33. A demodulator 72 at the digital TV receiver 5 for picture reception converts the data into a digital data, an S/P conversion circuit 28 converts the data into a parallel picture data and it is written in a picture memory 61. The picture data written in the picture memory 61 is rand by the memory controller 62 and outputted on a monitor 64.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to digital television (hereinafter simply referred to as digital
This invention relates to an image transmission device between digital TV receivers that enables image transmission between receivers (denoted as V).

[Prior Art] The currently widely used TV (television) receivers are analog receivers that use analog technology for the signal processing system that processes incoming TV signals and outputs images to a CRT (cathode ray tube). Since these are TV receivers, images (for example, color still images) cannot be transmitted between these analog TV receivers. Recently, digital TV receivers that use digital technology in their signal processing systems (e.g. l": l)
TV(E)(tended Defjnjtion T
Although a digital TV receiver (e1evision) has been developed, there is nothing that transmits images between these digital TV receivers.

[Problems to be Solved by the Invention] As mentioned above, it is not possible to transmit images between analog TV receivers that are currently in general use, and there is no way to transmit images between digital TV receivers. There has been a problem in that images (for example, color images taken with a video camera) cannot be transmitted between digital TV receivers using a line (for example, a general-purpose telephone network). The present invention has been made in view of the above-mentioned problems, and utilizes an image memory built into a digital TV receiver (for example, a frame memory in which image data for one frame is written), and uses a transmission line to receive digital TV images. It is an object of the present invention to provide an image transmission device between digital TV receivers that can transmit images (for example, color still images) between the receivers.

[Means for Solving the Problems] The image transmission device between digital TV receivers according to the present invention includes an A/D conversion circuit that converts a human-powered video signal into digital image data, and a memory controller 1-roller that performs read/write control. ,
An image memory into which image data output from the A/D conversion circuit is written, a D/A conversion circuit that converts the image data read from the image memory into an analog video signal, and this D/A conversion circuit. Two digital TV receivers each equipped with a monitor for displaying the converted video signal on a display screen are provided, one of the two digital TV receivers is used for transmitting images, and the other is used for receiving images. , a parallel-to-serial conversion circuit for converting parallel image data read from the built-in image memory into serial data and outputting the same on the digital TV receiver for image transmission; and this parallel-to-serial conversion circuit. a modulator that modulates the data output from the transmission line into an analog signal and outputs it to the transmission line, and a demodulator that demodulates digital data from the analog signal transmitted by the transmission line on the digital TV receiver side for image reception. a serial/parallel conversion circuit that converts the serial data demodulated by this demodulator into parallel image data and outputs it, and the image data output from this serial/parallel conversion circuit and a built-in A/D conversion circuit. The device is characterized in that it is provided with a switching circuit that switches the image data output from the image data to the built-in image memory and outputs the image data.

[Operation] On the side of a digital TV receiver for image transmission, an input video signal is converted into digital image data by an A/D conversion circuit, and written into an image memory whose read/write is controlled by a memory controller. At step 1, image data is read from the image memory, converted into an analog video signal by a D/A conversion circuit, and supplied to the monitor. Therefore, the monitor displays an image corresponding to the image data in the image memory.

Here, when image transmission is selected, image data read from the image memory is converted into serial data by a parallel/serial conversion circuit, modulated into an analog signal by a modulator, and transmitted to a transmission line.

On the digital TV receiver side for image reception, the analog signal transmitted by the transmission line is converted to a digital signal by a demodulator, converted to parallel image data by a serial/parallel conversion circuit, and then transferred to the image memory via a switching circuit. will be written to.

Next, the image data read from the image memory is converted into serial data by a parallel/serial conversion circuit, and then
The A conversion circuit converts the signal into an analog video signal and supplies it to the monitor. Therefore, the monitor displays an image corresponding to the image data in the image memory. As described above, images are transmitted from the digital TV receiver for image transmission to the digital TV receiver for image reception.

[Embodiment] The figure shows an embodiment of an image transmission device between digital TV receivers according to the present invention. In this figure, 1 is a digital RV receiver for image transmission, and 5 is a digital TV receiver for image reception.

The digital TV receiver 1 for image transmission has an antenna 3.
a tuner 12 that selects a predetermined color television signal from among a plurality of color television signals that are received by the user and input manually via the television signal input terminal 11; and an IF detection circuit 13 coupled to the output side of the tuner 12; , this IF detection circuit 1
Color video signals from 3 (hereinafter simply referred to as video signals) and multiple color video signal input terminals 14.15.16
A selection circuit 1 that selectively selects a video signal from color video signals (hereinafter simply referred to as video signals) input from
7 and the A/D (
analog/digital) conversion circuit] 8, a Y/C (luminance signal/color signal) separation circuit 19 connected to the output side of this A/D conversion circuit 18, and a Y/C (luminance signal/color signal) separation circuit 19 connected to the output side of this Y/C separation circuit 19. One individual terminal 20a of the switching circuit 20, movable piece 20m
and an image memory (for example, a frame memory into which image data for one frame can be written) 21 coupled via a common terminal 20c, and a memory controller 22 that controls reading and writing of this image memory 21.

A D/A (digital-to-analog) conversion circuit 23 connected to the output side of the image memory 21, a monitor 24 connected to the output side of the D/A conversion circuit 23, and a monitor 24 connected to the output side of the image memory 21. A parallel/serial (hereinafter simply referred to as P/S) conversion circuit 26 coupled via an on/off switch 25, a transmission data output terminal 27 coupled to the output side of this P/S conversion circuit 26, Transmission data input terminal 28
Then, the digital data input to the transmission data input terminal 28 is converted into serial/parallel data and outputted to the other individual terminal 20b of the switching circuit 20 (hereinafter simply referred to as S/P).
(described as ) conversion circuit 29. Transmission data output terminal 2 of the digital TV receiver 1 for image transmission
7 and the transmission data input terminal 28 are respectively M.O.D.E.
M, (Modulator/Demodulator) 30's modulator 31 and demodulator 32
and is coupled to one end of a transmission line (for example, a telephone line network) 40 via an NCU (network control unit) 33.

The digital TV receiver 5 for image reception, like the digital TV receiver 1 for image transmission, selects one of the plurality of color television signals received by the antenna 7 and inputted through the television signal input terminal 51. A tuner 52 for selecting a predetermined color television signal, an IF detection circuit 53 coupled to the output side of the tuner 52, a video signal from the IF detection circuit 53, and a plurality of video signal input terminals 54, 55 .
a selection circuit 57 that selectively selects a video signal from among the video signals inputted from the selection circuit 56; an A/D conversion circuit 58 coupled to the output side of the selection circuit 57; A Y/C separation circuit 59 coupled to the output side of the circuit 58, and one individual terminal 60a of a switching circuit 60, a movable piece 60m and a common terminal 60c are connected to the output side of this Y/C separation circuit 59.
an image memory (for example, a frame memory into which one frame's worth of image data can be written) 61, a memory controller 1 to roller 62 that control reading and writing of the image memory 61, and the image memory 61. a D/A conversion circuit 63 coupled to the output side of the D/A conversion circuit 63;
a monitor 64 coupled to the output side of the image memory 6;
1, a transmission data output terminal 67 connected to the output side of the P/S conversion circuit 66, and a transmission data input terminal. 68, and an S/P conversion circuit 69 which serially/parallel converts the data inputted to the transmission data input terminal 68 and outputs the converted data to the other individual terminal 60b of the switching circuit 60. Digital TV receiver 1 for image transmission
The transmission data output terminal 67 and the transmission data input terminal 68 are respectively connected to the modulator 7 of a MODEM (modulation/demodulation device) 70.
It is coupled to the other end of the transmission line (for example, telephone network) 40 via a demodulator 72 and an NCU (network control unit) 73.

Next, the operation of the above embodiment will be explained.

When using the digital TV receiver 1 for image transmission as a simple receiver, the movable piece 20m of the switching circuit 20 is connected to one individual terminal 20a, and the on/off switch 2
Turn off 5. Then, the video signal selected by the selection circuit 17 from among the color television signal and the color video signal is converted into digital image data by the A/D conversion circuit] 8, and is converted into digital image data by the Y/C separation circuit 19 (Y (luminance signal ) and C (color signal) and written into the image memory 21. The image data read out from the image memory 21 is converted into an analog video signal by the D/A conversion circuit 23, and then sent to the monitor 2.
4 is output. Therefore, the monitor 24 displays a color moving image corresponding to the input video signal. At this time, if the memory controller 22 stops writing to the image memory 21 and repeats reading from the image memory 21, the monitor 24 displays a color still image corresponding to the image data in the image memory 21. .

Even when the digital TV receiver 5 for receiving images is used as a simple receiver, the digital TV receiver 1 for transmitting images
Since this is the same as when the is used as a simple receiver, the explanation will be omitted.

Next, a case will be described in which a color still image is transmitted from the digital TV receiver 1 for image transmission to the digital TV receiver 5 for image reception.

On the side of the digital TV receiver 1 for image transmission, as described above, the image memory 21 is controlled by the memory controller 22.
Stop writing to the image memory 21, repeat reading from the image memory 21, and turn on the on/off switch 25 while displaying a color still image corresponding to the image data in the image memory 21 on the monitor 24. . Then, the image data read from the image memory 21 is converted into serial data by the P/S conversion circuit 26, and the MODE M
The signal is modulated into a predetermined analog signal by the modulator 31 of the (modulator/demodulator) 30 and output to the transmission line 40 via the NCU 33 .

On the digital TV receiver 5 side for image reception, a switching circuit 6
0 movable piece 60m is connected to the other individual terminal 60b, and the on/off switch 65 is turned off. And transmission line 4
0, the analog signal transmitted from the digital TV receiver 1 for image transmission passes through the NCU 73 of the MODEM 70, is converted into digital data by the demodulator 72, and is converted into digital data by the S/
The P conversion circuit 69 converts the data into parallel image data, which is then written into the image memory 61 via the switching circuit 60. The image data written in the image memory 61 is read out by the memory controller 62, and is read out by the D/A conversion circuit 63.
The signal is converted into an analog video signal and output to the monitor 64. Therefore, the monitor 64 displays a color still image corresponding to the image data in the image memory 61. Therefore, a color still image is transmitted from the digital TV receiver 1 for image transmission to the digital TV receiver 5 for image reception.

Contrary to the above, when transmitting a color still image from the digital TV receiver 5 side for image reception to the digital TV receiver 1 side for image transmission, the switching circuit on the digital TV receiver 5 side for image reception 60 movable piece 60m to one individual terminal 6
0a, turn on the on/off switch 65, connect the movable piece 20m of the switching circuit 20 on the side of the digital TV receiver 1 for image transmission to the other individual terminal 20b, and turn the on/off switch 25 off. Then, the color still image is transmitted from the digital TV receiver 5 for image reception to the digital TV receiver 1 for image transmission in the same manner as in the above case.

In the embodiment described above, color still images can be mutually transmitted between the digital TV receiver side for image transmission and the digital TV receiver side for image reception, but the present invention is not limited to this. It is also possible to transmit monochrome still images.

In the above embodiment, a switching circuit, an on/off switch, a P/S circuit, and an S/P are provided on each of the digital TV receiver side for image transmission and the digital TV receiver side for image reception.
MODEM consisting of circuit, modulator, demodulator and NCU
However, the present invention is not limited to this. , at least a P/S circuit and a modulator are provided on the side of the digital TV receiver for image transmission, and a switching circuit, an S/P circuit, and a demodulator are provided on the side of the digital TV receiver for image reception. Any device that can transmit an image from the digital TV receiver for image transmission to the digital TV receiver for image reception may be used. For example, on the side of the digital TV receiver 1 for image transmission shown in the figure, the switching circuit 2o and the S/P circuit 2
9, the on/off switch 25, and the demodulator 32 are omitted,
The output side of the Y/C separation circuit 19 is directly coupled to the image memory 21, and the output side of the image memory 21 is directly coupled to the P/S circuit 26. And a digital TV receiver 5 for receiving images.
On the side, an on/off switch 65 and a P/S circuit 66
and the modulator 71 may be omitted, and the image may be transmitted only from the digital TV receiver 1 side for image transmission to the digital TV receiver 5 side for image reception.

[Effects of the Invention] As described above, the image transmission device between digital TV receivers according to the present invention includes a parallel/serial conversion circuit and a modulator on the digital TV receiver side for image transmission, and a digital TV receiver for image reception. A demodulator, a serial/parallel conversion circuit, and a switching circuit are provided on the TV receiver side, and the image data written in the image memory of the digital TV receiver for image transmission is transferred to the digital data for image reception via a transmission line. Since the image is transmitted to the TV receiver side, written into its built-in image memory, and displayed on the monitor, images can be transmitted between digital TV receivers using a transmission line. Therefore, still images can be transmitted between digital TV receivers using a general-purpose telephone network as a transmission line. Therefore, instead of viewing still images taken with a video camera by oneself, the user can transmit them to others for viewing using a general-purpose telephone network.

[Brief explanation of the drawing]

The figure is a block diagram showing an embodiment of an image transmission device between digital TV receivers according to the present invention. 1...Digital TV receiver for image transmission, 5...Digital TV receiver for image reception, 18.58...A/
D conversion circuit, 21.61... Image memory, 22.62
...Memory controller, 23.63...D/A conversion circuit, 24.64...Monitor, 26...P/S conversion circuit (parallel/serial conversion circuit), 31...Modulator, 4
0...Transmission line, 60...Switching circuit, 69...S/
P conversion circuit (serial/parallel conversion circuit), 72... demodulator. Applicant Fujitsu General Ltd.

Claims (1)

[Claims] (1) An A/D conversion circuit that converts an input video signal into digital image data, an image memory that is controlled to read and write by a memory controller and into which the image data output from the A/D conversion circuit is written, and a D/A converts read image data into analog video signal
There are two digital TV receivers each equipped with a conversion circuit and a monitor that displays the video signal converted by the D/A conversion circuit on a display screen, and one of the two digital TV receivers is used for image transmission. Parallel/serial conversion for converting parallel image data read from the built-in image memory into serial data and outputting it to the digital TV receiver side for image transmission, with the other side used for image reception and the other side for image reception. circuit, and a modulator that modulates the data output from the parallel/serial conversion circuit into an analog signal and outputs it to a transmission line, and the data is transmitted to the digital TV receiver for image reception via the transmission line. A demodulator that demodulates digital data from an analog signal, a serial/parallel conversion circuit that converts the serial data demodulated by this demodulator into parallel image data and outputs it, and an image that is output from this serial/parallel conversion circuit. An image transmission device between digital TV receivers, comprising a switching circuit that switches data and image data output from a built-in A/D conversion circuit to a built-in image memory and outputs the same.