JPS61189739A - Transmitter of handwritten graphic - Google Patents

Abstract

PURPOSE:To cope successfully with both DPCM and chain coding systems by performing the sampling with the low sampling frequency of about 30Hz and producing the Freeman chain trains in eight directions and ian a size '1' from the obtained handwritten graphic data to perform the chain coding. CONSTITUTION:When the transmission is performed by means of the DPCM coding, this coding uses the relative coordinates to the continuation of strokes like a conventional graphic transmitter. While in a chain coding mode the relative coordinates obtained from a sampling processing part 3 are developed to the Freeman chain trains in eight directions and in a size '1' at an interpolating chain generating part 15. Thus the chain coding is carried out at a chain coding part 13 to said chain trains. In other words, the Freeman chain train can be coded directly or the DPCM (differential chain) coding system which codes the differential of the chain train can also be available.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a handwritten figure transmission device that samples handwritten figures, sequentially encodes them with high efficiency, and transmits the data.

[Conventional technology]

A conventional device of this type is shown in FIG.

In the figure, 1 is a coordinate detection unit that detects an analog signal X of the X coordinate as the position of the pen input from the tablet, an analog signal y of the X coordinate, and a signal Z indicating the top/bottom of the pen on the tablet; An A/D conversion unit 3 converts the signals x, y, and z detected by the coordinate detection unit 1 into A/D (analog-to-digital) at a constant sampling period; A sampling processing unit that determines the start and end of a stroke based on the continuity of the top and bottom signals of the pen and the relative displacement with the coordinates at the previous time with respect to the coordinate signals at each time. 4l-Il, DPCM (
Difference P CM ; Deduct PulseCode
Modulation) encoding unit, 5 is the above-mentioned D
a transmission data buffer that temporarily stores the transmission data encoded by the PCM encoding unit 4; 6 a communication control unit that controls transmission and reception while monitoring the transmission and reception status of the transmission line 12; 7; 8 is a receive data buffer that temporarily stores all received data transmitted through the transmission line 12tl under the control of the communication control unit 6; 8 is a decoder for the data stored in the receive data buffer 7; 9 is an interpolation processing unit for developing a sampled transmitted or received handwritten figure into an image in units of dots; 11 is an image display section for displaying the dot image stored in the image storage section 10; 12 is a transmission line, such as a CRT; and 12 is a transmission line.

Next, the operation will be explained. First, when the coordinate detection section 1 detects the analog signal X of the X coordinate, the analog signal y of the X coordinate, and the signal Z indicating the top/bottom of the pen regarding the position of the pen on the tablet, A/D conversion is performed at a sampling frequency (for example, about 60 Hz). Here, it is assumed that the coordinates after A/D conversion are Yi, and the upper and lower signals of the pen are t-Zi. Figure 11 also shows the katakana “i”
What is the sample point sequence I Pj ) when omitting ? It shows.

In the sampling processing unit 6, the continuity (up/down) of the pen up and down signals at the sampling points of the handwritten figure as shown in FIG.
The start, end, and continuation of a stroke are automatically determined based on the change in down (down), and relative coordinates (difference coordinates) with respect to the immediately preceding sample point are determined for the continuation point of the stroke.

In Figure 13, for data expressed in coordinates, I) E
', the data encoded by the CM encoder 4 is written to the transmission data buffer. The communication control section 6 performs all communication controls for transmitting the transmission data stored in the transmission data buffer 5 through the transmission line 12 or for receiving data transmitted through the transmission line 12.

The data received by the communication control unit 6 is stored in the reception data buffer 7, and then decoded by the DPCM decoding unit 8 at the subsequent stage. The handwritten figure data obtained in the DPCM encoding section 4 and the DPCM decoding section 8 is developed into a dot image in the interpolation processing section 9, and then stored in the image storage section 10 and displayed on the image display section 11. .

[Problem that the invention seeks to solve]

Since the conventional handwritten figure transmission device is configured as described above, it can be applied to communication using DPCM encoding, but it is not suitable for high-speed handwritten figure input ( fast sampling) and chain detection, etc., and cannot be applied. Therefore, the encoding method for communication is limited to DPCM encoding only, and there are problems such as a structure that is not applicable to either DPCM encoding or chain encoding.

This invention was made to solve the above-mentioned problems, and unlike the conventional handwritten figure transmission device that uses only DPCM encoding, it is capable of sampling handwritten figures at a sampling frequency as low as 3011z. conduct and DPCM
The overall purpose of the present invention is to obtain a handwritten figure transmission device capable of mutual communication with both encoding systems and chain encoding.

[Means to solve all problems]

The handwritten figure transmission device according to the present invention replaces the interpolation processing section in the conventional handwritten figure transmission device with an interpolation chain generation section that generates an interpolation chain from sampled coordinates, and newly creates a code for chain encoding. It is provided with an encoding section and a decoding section.

[Effect]

In this invention, in addition to conventional DPCM encoding, chain encoding is also sampled at a low sampling frequency of about 30 Hz, which is the same as that used in DPCM encoding.
From the handwritten figure data obtained by the sampling, a Freeman chain array of size l in eight directions is generated by linear interpolation processing, and chain encoding is performed. It also corresponds to encoding.

〔Example〕

Hereinafter, all drawings of an embodiment of the present invention will be described.

In FIG. 1, the same parts as in FIG. 10 are indicated by the same reference numerals. In FIG. 1, 13 is a chain encoding section, 14 is a chain decoding section, and 15 is an interpolation chain generating section.

Next, the operation of this invention will be explained. First, an analog signal X of the Xi mark related to the position of the pen on the tablet, an analog signal Y of the Y coordinate, and a signal Z indicating the top/bottom of the pen.
can be detected by the coordinate detection unit 1, and if the sampling period is a constant, for example, the sampling frequency f is about 30 Hz, then the distance is 33 m.
A/D conversion is performed in the A/D converter 2 in 5ec. Here, if the coordinates after A/D conversion are tXiyYi and the pen top and bottom signals are t-Zi, then the sampling point sequence IPi) is the 11th
It is the same as the haze in the figure. Next, based on the A/D converted coordinates, the sampling processing unit B calculates the start and end of the stroke and the relative coordinates with respect to the immediately preceding sampling point based on the continuity of the pen. When transmitting using DPCM encoding, DPCM encoding is performed in which the continuation of a stroke is encoded using relative coordinate tones, as in the conventional apparatus. When transmitting using chain encoding, as shown in FIG. 2, the interpolation chain generation section 15 expands the relative coordinates obtained in the sampling processing section 3 into an 8-direction Freeman chain array of size 1. In this way, a chain sequence as shown in FIG. 3 is obtained in the interpolation chain generating section 15, and the chain encoding section 1
Chain encoding is performed in step 3. That is, as chain encoding, the Freeman chain sequence may be encoded as it is, or DPCM (differential chain) encoding that encodes the difference between the chain sequences as shown in FIG. 4 may be adopted.

An example of the code is shown in FIG. Next, writing to the image storage section 10 is performed by directly writing as a dot image from the chain array in eight directions obtained from the interpolation chain generation section 15. Regarding image power distribution when using DPCM encoding,
The aforementioned interpolation chain generation section 15 generates an 8-way identical chain sequence of size 1, and writes the chain sequence into the image storage section 10 as a dot image. DPCM encoder 4
, or the data encoded by the chain encoding unit 13 is once stored in the transmission data buffer 5 and sent to the transmission line 12 by the communication control unit 6. On the other hand, the received data sent through the transmission line 12 is controlled by the communication control section 6 and then temporarily stored in the received data buffer 7.

If the accumulated received data is transmitted by DPCM, it is decoded by the DPDM decoding section 8, developed into a dot image by the interpolation chain generation section 15, and stored in the image storage section 10. If communication is based on chain encoding, the chain decoding unit 14
The image is decoded and written to the image storage unit 10 as a red dot image. The image data of the dot image stored in the image storage section 10 is stored in the image display section 1.
1.

In addition, in the above-mentioned embodiments, a configuration that can be applied to both chain encoding and DPCM encoding based on an 8-direction chain array of size 1 was shown.
Window chain encoding and DPCM based on window chain encoding method using directional chain sequence Vt
An example of a configuration that can be applied to either encoding is the circuit configuration shown in FIG. In this case, there are 20 types of window chain codes from -9 to ~10 as shown in Figure 7, and at the end of the stroke,
E0 to E corresponding to the internal position of the window as shown in Figure 8.
Encode the code of I4. Then, the window chain expansion unit 17 in FIG. 6 expands the window chain code into a freeman chain code string as shown in FIG.

In the above embodiment, regarding DPCM encoding, the case where the continuation of a stroke is constant-length encoded with respect to relative coordinates has been described. However, if the size of relative coordinates exceeds a predetermined size, it is necessary to apply modified DPCM encoding that encodes using absolute coordinates. In this case, the DPCM encoding section and the DPCM decoding section may be replaced with corresponding encoding/decoding sections. Similarly, when applied to zone encoding, D
This can be handled by modifying the PCM encoder/decoder for zone encoding.

〔Effect of the invention〕

As described above, the present invention provides a circuit that can be applied to communication using either DPCM encoding or chain encoding even when sampling is performed at a sampling frequency as low as the tablet pen position coordinate f 30 Hz. Since it was configured,
Does not require a high-speed sampling input device and can be used with DPC
The present invention is not limited to M-encoding, but has the advantage that it becomes possible to communicate with handwritten figure transmission devices that could only communicate with each other using the chain encoding method.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a handwritten figure transmission device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of an 8-direction chain of size 1, and FIG. 3 is an explanatory diagram of an example of relative coordinates and an interpolation chain train. Figure 4 is an explanatory diagram of the differential chain encoding method, Figure 5 is a code diagram of the Freeman code and differential chain code, and Figure 6 is handwritten figure transmission that can support both DPCM encoding and window chain encoding. A block diagram of the device, Fig. 7 is an explanatory diagram of the window chain, Fig. 8 is an explanatory diagram of internal coordinate position representation at the end of a stroke, and Fig. 9 is a diagram of the transformation from a window chain to a freeman chain. Table diagram, Figure 10 is a block diagram of a conventional handwritten figure transmission device, Figure 11 is an explanatory diagram showing an example of a sample point sequence when the handwritten figure in Figure 10 is sampled, and Figure 12 is a sample point sequence. FIG. 13 is an explanatory diagram of relative coordinate expression. In the figure, 1 is a coordinate detection section, 2 is an A/D conversion section, 3 is a sampling processing section, 4 is a DPCM encoding section, and 5 is a transmission data/data conversion section.
buffer, 6 is a communication control unit, 7 is a received data buffer, 8 is a DPCM decoding unit, 10 is an image storage unit, 11 is an image display unit, 16 is a chain encoding unit, 14 is a chain decoding unit, 15 is a 1 is an interpolation chain generation unit, 16 is a window chain synthesis unit, 17 is a window chain expansion unit, 1
8 is a window chain encoding section, and 19 is a window chain decoding section. Figure 2 Figure 3 Figure 5 Figure 9 Figure 11 ■ Procedural amendment (voluntary)

Claims (2)

[Claims] (1) A/
The handwritten data is converted into a digital signal by the D conversion unit, the relative displacement of the sample point on the coordinates of the handwritten figure is determined by the sampling processing unit, and the relative coordinates of the sample point are subsequently encoded by the DPCM encoding unit. In the figure transmission device, while data is transmitted via the communication control unit, the received data is decoded in the DPCM decoding unit, and the transmitted and received handwritten figures are stored in the image storage unit and displayed as images. In addition, when transmitting chain encoding, the relative coordinates of the sample points are expanded into an 8-direction Freeman chain string of size 1 in the interpolation chain generation section, and the chain encoding section encodes the chain and transmits it. When receiving chain encoded data, the data is loaded into the image storage unit via the chain decoding unit and is compatible with either DPCM encoding or chain encoding depending on the encoding selection of the transmission device on the transmitting side. Features of handwritten figure transmission device (2) A handwritten figure is sampled at a predetermined sampling frequency and encoded in the DPCM encoder in accordance with the encoding method of the recipient's transmission device, or an 8-directional Freemanchen string of size 1 is encoded all at once. a window chain synthesis unit that encodes and transmits the output of the window chain synthesis unit, and a DPCM decoding unit or window chain decoding unit that encodes and transmits the output of the window chain synthesis unit; The decoding unit decodes the signal, and the window chain expansion unit decompresses the decoded signal. A handwritten figure transmission device according to claim 1, characterized in that: