JPH02104082A - Still picture video telephone set - Google Patents

Abstract

PURPOSE:To receive a picture data correctly independently of the state of polarity of a telephone line by discriminating the polarity of the telephone line in preceding over the reception of a picture data so as to make the polarity coincident. CONSTITUTION:A CPU 11 is provided with a polarity discrimination means and a polarity coincidence means (not shown). The pattern of specific pattern 64 symbols (string of maximum amplitude and minimum amplitude) sent in preceding over a picture data is compared for each bit. When the patterns are coincident, a coincidence counter is counted up and whether or not all patterns are received is discriminated. In the case of YES, when the coincidence rate is 25% or below, 0 is substituted to a negative flag. When the coincidence rate is 75% or over, after '255' is substituted in the negative flag, the carry is set and the return state is transited.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a still image video telephone device that transmits and receives still images to and from a called party via a telephone line.

[Prior Art] There is a demand for a videophone device that simultaneously transmits audio signals and image data using a telephone communication line, but in reality, current telephone lines cannot transmit dynamic images that require a huge amount of data. It is difficult to continuously transmit and receive images, and still image videophone devices that transmit still images to the other party during a call are being put into practical use.

This still image videophone device temporarily interrupts a normal voice call and sends a desired still image, such as the caller's face, a photo screen, or a picture depending on the content of the call. Is possible.

Therefore, according to such a still image videophone device, it is possible to send and receive images over a telephone line, which was previously impossible, and the amount of data processing is also limited because only one still image is sent each time. This has the advantage that it is easy to put videophones into practical use.

A still image video telephone device capable of transmitting still images as described above is disclosed in, for example, Foreign Communication Technology October 1986 issue. FIG. 2 is a line configuration diagram of the simple still image video telephone device.

In the figure, (1) is a handset, (2) is a microphone, (3) is an audio input/output circuit, (4) is an analog circuit, (
5) is a matrix switch, (6) is a telephone interface circuit, (7) is a telephone line connection terminal, (8) is a speaker, (9) is a keypad, (10) is an input/output port, (1)
1) is the CPU.

(12) is a program memory, (13) is a modulation/demodulation circuit,
(14) is a television camera, (15) is an image controller, (16) is an image memory, and (17) is a display.

Next, the operation of transmitting audio signals and image data in this conventional still image video telephone device will be explained based on FIGS. 2 and 3.

In Figure 2, a voice call is transmitted from the handset (1) or microphone (2) to the telephone line via the voice input/output circuit (3), analog circuit (4), matrix switch (5), and telephone interface circuit (6). It is sent to the connection terminal (7). Further, the audio signal from the other party is reproduced by the handset (1) or the speaker (8) via a path opposite to the above-mentioned signal path.

Here, when transmitting image data, as shown in Fig. 3, in order to confirm whether the other party is using a still image videophone device capable of communicating image data in the same data format,
A header containing an ID code such as data regarding capabilities is sent. Then, after receiving the header back from the other party and confirming that the other party has similar capabilities, the image data is transmitted.

That is, in FIG. 3, when the keypad (9) is used to instruct image data transmission, the CPU (11) detects this via the human output port (10) and executes the process according to the program stored in advance in the program memory (12). The header is sent to the modulation/demodulation circuit (13).

After modulating this header into an analog signal, it is sent to a telephone line connection terminal (7) via a matrix switch (5).
Send from. The header from the communication partner passes through a path opposite to the above-mentioned signal path, and the CPU (11) checks the code, etc.

Meanwhile, the image data taken by the television camera (14) during this period is quantized by the image controller (15), stored in the image memory (16), and then sequentially reproduced by the instructions of the CPU (11) and displayed on the display (17). ) and is output to the telephone line connection terminal (7).

Furthermore, when a header is input from the other party, the matrix switch (5) recognizes that the reception of image data is about to start, and uses the carrier signal received by the matrix switch (5) to transmit the received signal from the telephone interface circuit (6). The signal is switched so that it is not sent to the analog circuit (4) but sent only to the modulation/demodulation circuit (13).

After demodulating the received signal in the modulation/demodulation circuit (13), the CPU (11) returns the header or stores the data in the image memory (16), and
5), the image data is sequentially derived and displayed on the display (
17).

Note that after the transmission and reception of image data is completed, the modulation/demodulation circuit (13
), the matrix switch (5) connects the telephone interface circuit (6) and the analog circuit (4) to restore communication using voice signals.

Furthermore, if the reply from the receiving side is to be omitted, information regarding the omission is included in the header, and the image data is transmitted following the header. In this case, the receiving side still prepares to receive the image data using this header.

[Problems to be Solved by the Invention] Since the conventional still image videophone device is configured as described above, it is not possible to determine the polarity state of the telephone line. For this reason, for example, in a telephone device such as a private telephone device that does not reverse the polarity, there is a problem in that the sending and receiving sides perform a reception operation with the polarity of the telephone line mismatched, and white image data is received as black image data. there were.

This invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a still image video telephone device that can correctly receive image data regardless of the polarity state of the telephone line. .

[Means for Solving the Problems] A still image videophone device according to the present invention includes a determining means for determining a match rate with a specific pattern transmitted in advance of image data, and a method according to a determination result by the determining means. A control device that controls the image memory and the display device is provided with a setting device for determining the polarity based on the image data.

[Operation] The polarity determining means in the present invention determines, bit by bit, whether or not the receiving side matches a specific pattern sent from the transmitting side prior to the image data, and determines the polarity state based on the matching rate. However, by matching the polarities with the polarity matching means according to the result of this determination, it is possible to correctly receive image data regardless of the polarity state of the telephone line.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. The overall configuration of the still picture videophone device is the same as that of the conventional still picture videophone device shown in FIG. It is.

Next, the operation will be explained with reference to the flowchart shown in FIG. First, when the operation is started in step STI, image data is received in step ST2, and a specific pattern, for example, 64 symbols (sequence of maximum amplitude and minimum amplitude) sent prior to this image data, is input bit by bit in step ST3. Compare patterns.

Then, in step ST4, it is determined whether or not there is a match, and Y
In the case of ES, after counting up the coincidence counter in step ST5, in the case of NO in step ST4, it is determined in step ST6 whether all patterns have been received.

If the IWi result is NO, return to step ST2 and repeat the above operation; if YES, calculate the match rate in step ST7, and then determine whether the match rate is 25% or less in step ST8. .

If the determination result is YES, O is substituted into the negative flag in step ST9, and if NO, it is determined in step 5TIO whether the coincidence rate is 75% or more.

Then, if the judgment in step 5TIO is YES, in step 5TII, after substituting r255J for the negative sign flag,
After the operation of step ST9 above, step 5T12
Carry is set in step 5T14. Further, if the judgment in step 5TIO is NO, this means that the telephone line condition has deteriorated, so carry-set is performed in step 5TI3, and the process moves to return in step 5T14.

[Effects of the Invention] As described above, according to the present invention, the polarity of the telephone line is determined prior to reception of image data and the polarities are matched, so that regardless of the polarity state of the telephone line, This has the advantage that image data can always be received correctly.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the operation of a still picture video telephone device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a conventional still picture video telephone device, and FIG. 3 is a conventional still picture television telephone device. 3 is an operation flowchart of the telephone device. In the figure, (11) is the CPU (control device), (14
) is a television camera, (16) is an image memory, and (17) is a display (display device). In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Figure 1 of the flowchart group showing the agent, patent attorney Masuo Oiwa (and 2 others) as force 1'J

Claims (1)

[Scope of Claims] An image memory that stores image data of captured images taken with a television camera and received images transmitted from the other party over a telephone line, and displays image data reproduced from images from this image memory. A videophone comprising: a display device; and a control device that controls storage and reproduction of image data in the image memory, displays the reproduced image data on the display device, and transmits and receives the reproduced image data to and from the other party through the telephone line. The apparatus includes: a polarity determining means for determining a polarity state by determining a matching rate for each bit of a specific pattern transmitted in advance of image data; and a polarity matching device for matching polarity according to a determination result by the polarity determining means. A still picture video telephone device, characterized in that the control device is provided with: means.