JPH0231545B2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Description of the field to which the invention pertains The present invention relates to a system that encodes, transmits, decodes, and reproduces and displays stroke information such as handwritten characters and figures, and is capable of solving the problem when a transmission error occurs. The present invention relates to a method for indicating to an operator that a transmission error has occurred.

(2) Description of conventional technology Conventionally, in a drawing image communication system that transmits stroke information such as handwritten characters and figures, the first
It had the configuration shown in the figure. That is, the coordinates detected by a position coordinate detector 1 such as a tablet are sampled by a sampler 2 at a rate of about 40 samples per second and input to an encoder. The encoded data is sent to a decoder 5 via a transmission path 4, and the reproduced sample point sequence is interpolated between sample points by a linear interpolator 6, and then written to a refresh memory 7. is displayed on the display 8.

Here, when using a normal analog telephone line etc. as the transmission path 4 and multiplexing and transmitting audio and image signals, position coordinates are encoded in relative coordinate format in order to reduce the amount of transmission codes. -DPCM
Encoding methods etc. are used. However, with relative coordinate format encoding, correct position coordinates after the point where a transmission error occurs cannot be reproduced. Therefore,
Conventionally, as a countermeasure against code errors, code error detection means such as parity were provided, and if a code error occurred, the inserted absolute coordinates could be correctly decoded and displayed according to predetermined rules. The company used a method to stop displaying the information until it became available. Since the rate at which absolute coordinates are transmitted is approximately one point per stroke (range that can be written with one stroke) in relation to the amount of code, this method may result in one stroke not being displayed at all.

When simultaneous communication of audio and graphic images is carried out, it is possible to fill in the missing parts of the graphic image caused by coding errors to some extent with conversation, but when a hearing-impaired person uses the system only for written communication, In cases such as when only a drawn image is transmitted unilaterally, it is not possible to simply stop displaying the part where a transmission error has occurred. As can be seen in the example shown in Figure 3, there was a risk that important information would be missing.

(3) Purpose of the Invention In order to eliminate these drawbacks, the present invention aims to solve the following problems: When a transmission error occurs, the last point that could be correctly reproduced before the error occurred or the first point that normal decoding could be restarted. A mark indicating that an error has occurred is displayed at the point, which will be explained below using the drawings.

(4) Description of structure and operation of the invention FIG. 4 shows the structure of a system according to an embodiment of the invention. The configuration of the system of this embodiment is compared with the configuration of the conventional method shown in FIG.
The difference is that a mark pattern generation circuit 9 is added. When the decoder 5 detects an error, the display is stopped, and at the same time, a mark pattern generation circuit 9 generates a mark indicating that an error has occurred, and writes it in the refresh memory 7 and displays it. The error mark is written in the refresh memory 7 so that it is displayed at the point immediately before a transmission error occurs or at the first point at which decoding was successful. The mark pattern generation circuit 9 may have a similar configuration to a character pattern generator, and generates a mark corresponding to the input code in the form of a dot pattern. The refresh memory 7 is composed of a memory corresponding to a display screen and a dot.

5 and 6 show how the error mark is displayed. In FIG. 5, P ₁ , P ₂ , . . . are sample point sequences to be transmitted. In Fig. 5, assuming that a transmission error occurs while receiving P ₆ , the last point displayed as shown in Fig. 6 is P ₅ , so an error mark “□×” will be placed above P ₅ . ” is displayed. In addition, as shown in Fig. 7, the error occurrence point a
When is the beginning of a stroke, an error mark “□×” is displayed at the rear end of the previous stroke as shown in FIG.

The above explanation uses an example of attaching an error mark to the last point that was correctly decoded. Of course, it may also be the first point at which decoding can be resumed normally.

The shape of the error mark is shown as “□×” in Figure 6,
Of course, the size, shape, etc. are free. In addition, if a transmission error occurs, this method can be used in combination with other display methods such as lamps, or a method that displays a message indicating that an error has occurred at a fixed position on the screen, for even greater effectiveness. is obtained. Further, for stroke portions that are lost due to transmission errors, it is also possible to perform retransmission or other commonly used correction methods.

(5) Explanation of effects As explained above, according to the present invention, sentences,
In a system that encodes, transmits, and displays stroke information such as graphics, when a code error occurs, a mark is displayed to indicate that the code error occurred at the location temporally closest to the part where the code error occurred. Therefore, there is an advantage that the operator can quickly and reliably check for code errors when reading the display screen.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a conventional system, FIGS. 2 and 3 are display screen diagrams when a code error occurs in the conventional system, FIG. 4 is a configuration diagram of a system according to an embodiment of the present invention, and FIGS. FIG. 8 is an explanatory diagram of the error mark display method according to the present invention. In the figure, 1 is a position coordinate detector, 2 is a sampler, and 3
4 is an encoder, 4 is a transmission line, 5 is a decoder, 6 is a linear interpolator, 7 is a refresh memory, 8 is a display, and 9 is a mark pattern generation circuit.

Claims (1)

[Claims] 1. In a system that encodes, transmits, decodes, and reproduces and displays stroke information such as handwritten characters and geometric figures, there is a means for detecting code errors, and a means for storing the position coordinates of the latest correctly decoded stroke information. , means for displaying a mark on a display screen, and when a code error is detected by the code error detecting means, the position coordinates are stored by the storing means. The position coordinates of the stroke playback point immediately before the previous stroke playback point, or the position coordinates of the stroke playback point immediately after the correct absolute position coordinates are decoded for the first time after normal code reception is resumed, are used to confirm that an error has occurred. 1. A method for visually displaying a transmission error in graphical image communication, characterized by displaying a mark indicating the position on an area including the position coordinates.