JPH0441861B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an image communication device that transmits handwritten characters, figures, etc. along with voice over a telephone line, and more specifically, it relates to a device that does not require voice communication. The present invention proposes a drawn image communication device that can communicate at high speed when the drawn image contains less information as run length information than as stroke information.

[Prior art]

Conventional handwritten image communication devices allocate approximately 1900 to 2300Hz of the frequency band of 300 to 3400Hz processed by telephone lines to communication of handwritten images in order to make it possible to transmit handwritten images while having a conversation. was. Because of this narrow band communication, the transmission speed was as low as 300 bps. and,
Even if you only want to transmit a drawing while the other party is absent, or if you do not need to have a conversation even if the other party is present, in other words, even if there is no need to transmit an audio signal, They were forced to transmit at low speeds.

Some of these hand-drawn image communication devices have a bulk communication function, but the hand-drawn image information is stored by performing modified differential encoding on the stroke information obtained from the drawing tablet and storing it in a memory with a finite capacity. Therefore, if the image information exceeds the memory capacity, it is impossible to store any more image information, so it is necessary to prohibit the input of any more image information. In particular, the memory also stores partial deletion information for drawing, so even if there is little image information when storage is complete, there is a lot of data stored in the memory, and all of this is sent, so the transmission speed is slow as described above. Combined with this, communication was taking a long time.

〔the purpose〕

The present invention has been made to eliminate such inconveniences, and by providing two modems with different transmission speeds, one high and one low, and selectively using them, efficient transmission can be achieved. This enables high-speed communication when voice communication is not required or when bulk communication is required, and furthermore, it not only encodes handwritten image information as stroke information, but also encodes it as run length information of the image itself, and encodes it to be transmitted in bulk. An object of the present invention is to provide a graphic image communication device that achieves high speed by transmitting the smaller amount of data.

A drawing image communication device according to the present invention is a drawing image communication device that multiplexes handwritten drawing image information with an audio signal and transmits the same, and includes a first modem that modulates and demodulates the handwritten drawing image information and a transmission speed higher than that of the first modem. a switch for selectively inputting hand-drawn image information to the first or second modem; and a multiplexing circuit for multiplexing the modulated output of the first modem and the audio signal. Features. Further, in a drawing image communication device that multiplexes hand-drawn image information with an audio signal and transmits the same, the device includes a video memory that stores the hand-drawn image information, a first encoding circuit that encodes stroke information of the hand-drawn image information; A second encoding circuit encodes the binary run length of the information stored in the video memory, and each of the first and second encoding circuits determines the amount of encoded information. A comparison circuit for comparison,
a first modem that modulates encoded hand-drawn image information; a diode modem having a higher transmission speed than the first modem; and selectively inputting the encoded hand-drawn image information to the first or second modem. and a multiplexing circuit that multiplexes the modulated output of the first modem and the audio signal, and is configured to provide the encoding circuit output having a smaller amount of information to the second modem by comparison of the comparison circuit. The second feature is that

[First Embodiment] The present invention will be described in detail below based on drawings showing embodiments thereof. FIG. 1 is a block diagram of a first embodiment of the present invention.

In the figure, reference numeral 1 denotes a drawing tablet, and when simultaneous communication of drawing and voice is commanded using the operation switch 1b, when handwriting is done on paper loaded on the pressure-sensitive pad 1a, the coordinate information is read at a fixed sampling period and sent to the control unit 2. taken inside. The control unit 2 supplies the stroke information of the drawn image to the first modem (modulator/demodulator) 4 via the switch 3, where it is FSK modulated.
The FSK-modulated graphic image information is input to the demultiplexing circuit 5 together with the audio signal from the telephone 8, where the graphic image information is multiplexed into this band except for the 1900 to 2300 Hz portion of the audio signal, and the multiplexed signal is It is sent out to the telephone line via switch 7. The drawn image information is also written into the video memory 10 by the control section 2 and displayed on the monitor 9.

Conversely, the signal received through the telephone line is inputted to the multiplexing/demultiplexing circuit 5 via the switch 7, where it is separated into an audio signal and a graphic image information signal, and the former is given to the telephone 8. On the other hand, the latter is demodulated by the first modem and input to the control section 2 via the switch 3, and the drawn image information is written into the video memory 10 by the control section 2 and displayed on the monitor 9.

In the device of the present invention, when drawing-only communication is instructed by operating the operation switch 1b, the control section 2 receives this instruction and switches the switches 3 and 7 to the side shown by the broken line, and connects the second modem 6 between the two switches 3 and 7. to intervene.
The second modem 6 has a higher transmission rate of 4800 (or 2400) baud compared to the 300 bps transmission rate of the first modem. The drawn image signal is then applied to the second modem 6 via the switch 3, where it is modulated at high speed and sent via the switch 7 to the telephone line. In the case of reception, the signal is similarly applied to the second modem 6 for high-speed demodulation, inputted to the control section 2, and displayed on the monitor 9.

The operation of the device of the present invention is performed as follows. That is, the switches 3 and 7 are initially set to the first modem side as shown by solid lines. If the telephone 8 is used to call the other party's machine and simultaneous communication of drawn image information and audio signals is to be performed, an instruction is given using the operating switch 1b. Then, the audio signal is sent out to the telephone line via the demultiplexer circuit 5 and the switch 7, the image information is sent out to the telephone line via the switch 3, the first modem 4, the demultiplexer circuit 5, and the switch 7, and the received signal is sent out through the reverse route. The voice is sent to the telephone 8 and monitor 9, and
Reproduced as an image.

If voice communication is not required, the operation switch 1b instructs high-speed communication using the second modem. In this case, in response to an instruction from the operating switch 1b, a high-speed modem use request signal is first sent to the communication partner via the low-speed first modem 4. If the other party is the device shown in FIG. 1 like the transmitting side, the control unit 2 that received this sends back a permission signal. Upon receiving this, the control section 2 of the transmitting side device switches the switches 3 and 7 to the second modem 6 side, and only the drawing image information inputted from the drawing tablet 1 is modulated at high speed by the second modem and transmitted. At the same time as the permission signal is sent, the other party's machine also switches to the high-speed modem side, demodulates the received signal, and displays it on the monitor 9. After transmission, both devices switch to the original low-speed first modem side of switches 3 and 7.

If the other party's machine is not equipped with a high-speed modem, it will issue a rejection signal or will not issue a permission signal. Communicate. In this case, an appropriate lamp provided on the drawing tablet 1 indicates that high-speed communication is not possible.

In this way, communication time can be shortened.

[Second Embodiment] FIG. 2 is a block diagram showing the configuration of a second embodiment. Components that are the same as in FIG. 1 are given the same reference numerals.

In this embodiment, in addition to the memory 10, there is provided a video memory 12 dedicated to storage for batch communication, and a memory 11 for writing information obtained by modifying and differentially encoding stroke information of an image input to the drawing tablet 1. .

In this embodiment, according to instructions from the operating switch 1b of the drawing tablet 1, voice communication using only the telephone 8, simultaneous communication of drawn image information handwritten on the drawing tablet 1 and voice, and high-speed communication of only the drawn image information are possible. In addition to being able to perform the same operations as in the first embodiment described above, batch communication can also be performed.

The case where batch communication is performed will be explained below with reference to the flowchart of FIG. The control section 2 writes the input information from the drawing tablet 1 into the video memory 12 as image information as it is, and displays this on the monitor 9. On the other hand, the control section 2 encodes the stroke information of the pen on the pressure sensitive pad 1a into a modified differential code and writes it into the memory 11. When inputting the end of writing with the operation switch 1b, the control unit 2
The encoder performs modified Huffman (MH) encoding (modified read encoding may also be used) on the image information written in the video memory 12, and counts the amount of information generated thereby. Here, the encoded information does not necessarily have to be stored, and only the amount of information needs to be stored. Further, when an input that exceeds the storage capacity of the memory 11 is received, the control unit 2 stores the fact that there has been an overflow, and does not perform modified differential encoding or storage after the overflow.

The control unit 2 then compares the amount of information of the MH encoding described above with the amount of information stored in the memory 11. The amount of information of the modified differential code is as follows:
Since the data is stored sequentially from the first address of 1, the value of the address counter at the end of input may be used.
As a result of this comparison, if the amount of modified differentially encoded information is small, the contents of the memory 11 are transmitted;
If the amount of MH-encoded information is small, the contents of the memory 12 are MH-encoded and transmitted.

In the case of batch communication, the control section 2 switches the switches 3 and 7 to the dotted line side to perform modulation using the high-speed first modem, and also demodulates using the same modem during reception.

Note that if the memory 11 is overflowing, the input drawn image information is not completely stored in the memory 11, so in this case, the contents of the video memory 12 are transmitted.

〔effect〕

As described above, according to the present invention, when voice communication is not necessary, the drawn image information that is input sequentially can be transmitted at high speed using the second modem 6, and when voice communication is not necessary, the same modem 6 can be used to transmit the drawn image information all at once. Since high-speed communication can be performed and a smaller amount of information can be communicated at that time, communication time can be significantly reduced in both cases. The present invention has excellent effects such as being able to completely transmit the drawn image regardless of the overflow of the memory 11.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the first embodiment, FIG. 2 is a block diagram of the second embodiment, and FIG. 3 is a flowchart showing the processing contents of the control section of the second embodiment. 1...Drawing tablet, 2...Control unit, 3, 7
...Switch, 4...First modem, 5...Demultiplexing circuit. 6...Second modem, 8...Telephone, 9...
...Monitor, 10, 12...Video memory, 11...
…memory.

Claims (1)

[Claims] 1. A drawing image communication device that multiplexes hand-drawn image information with an audio signal and transmits the same, comprising: a video memory that stores hand-drawn image information; a first encoding circuit that encodes stroke information of the hand-drawn image information; A second encoding circuit encodes the binary run length of the information stored in the video memory, and the first and second encoding circuits each calculate the amount of encoded information. a comparison circuit for comparing; a first modem for modulating encoded hand-drawn image information; and a second modem having a higher transmission speed than the first modem; It is equipped with a switch for selectively inputting the input to the two modems, and a multiplexing circuit for multiplexing the modulated output of the first modem and the audio signal, and the output of the encoding circuit with a smaller amount of information is selected by the comparison circuit. A graphical image communication device, characterized in that it is configured to be transmitted to a second modem.