JPH04284085A - Communication terminal equipment for image display - Google Patents

Abstract

PURPOSE:To reduce the burden of a user by reloading only a part generating error while ignoring a picture erase code added into image data received again. CONSTITUTION:When the error of data is detected, the terminal equipment displays an 'X' mark at the left upper part of a picture display screen, the error generation is recognized by the user of the terminal equipment and simultaneously, after the lapse of fixed time when image data are completely received, a retransmission code is automatically transmitted to an information center. The information center receiving this re-transmission code transmits the same data as the image data to the terminal equipment again. At such a time, the terminal equipment reloads only the part generating the error in the picture, which generates the error, transmitted until the re-transmission with image data subjected to the decode processing of image data to be continuously transmitted while ignoring the erase code and displays the normal image on the image display device of a television receiver or the like.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display communication terminal device that connects to an information center, receives image data, decodes it, and displays an image.

0003

2. Description of the Related Art Videotex systems have become widespread, which store data supplied by information providers in an information center and provide the stored information to users in response to requests from user terminals. In this Videotex system, data such as image data is transmitted using a telephone line or the like as a transmission medium.

FIG. 5 is a block diagram showing a conventional Videotex terminal device.

The CPU 1 is a microprocessor that decodes data sent from the information center, receives an operating clock from the oscillation circuit 9, and performs various controls according to programs stored in the ROM 2. This R
The OM2 has a built-in program that processes image data received from the information center and converts it into image data to be output to an image display device. RAM3 is CPU
1 working memory, and also includes a reception buffer for temporarily storing data sent from the information center. The chip select circuit 4 is a circuit that is controlled by the CPU 1 and selects the ROM 2 and RAM 3. The data transmitting/receiving circuit 5 is a circuit that receives image data sent from the information center and stores it in a receiving buffer in the RAM 3 according to instructions from the CPU 1. The image display circuit 6 is C
This circuit displays image data decoded by the PU 1 on an image display device such as a television receiver (not shown).

When the information center and the data transmitting/receiving circuit 5 are connected via a transmission medium such as a telephone line, image data is guided from the information center to the data transmitting/receiving circuit 5. The data transmitting/receiving circuit 5 receives this image data and transmits it to the CP.
Transfer to U1. The CPU 1 specifies the address of the ROM 2 via the address bus, reads out a program stored in the ROM 2 that converts image data into decoded image data, and reads the program from the RAM based on this program.
3 is used to convert the image data from the data receiving circuit 5 into decoded image data and provide the decoded image data to the image display circuit 6. The image display circuit 6 displays an image on an image display device such as a television receiver (not shown) based on the decoded image data.

[0007] Here, the operation procedure between the information center and the terminal device when an error occurs in the data from the information center will be explained with reference to FIGS. 6 and 7. FIG. 6 is an explanatory diagram showing the operating procedure when an error occurs. Figure 7(A) shows the screen display when an error occurs.
B) shows the screen display that is erased by the screen erasing code added to the image data that is retransmitted at the user's request after an error occurs, and Figure 7 (C) shows the normal screen after error correction. Each display is shown below.

As shown in FIG. 6, image data transmitted from an information center is divided into a plurality of (n) packets and sent. The terminal device decodes the image data included in this packet according to the procedure explained above to form a screen. A CRC code for detecting data errors is added to the end of each packet. The terminal device uses this code to determine whether there is an error in the data, and if an error is detected, an "X" mark is displayed on the top left of the image display screen as shown in Figure 7 (A), and the user of the terminal device is informed of the error. Make them aware of what they have done. At this time, when the user operates the retransmission key on the terminal input device and requests to obtain a normal image, the terminal device transmits a retransmission code to the information center, and the information center that receives this retransmission code,
The same data as the image data is sent to the terminal device again. Normally, there is an image memory erasure code at the beginning of image data, so when this image data is retransmitted, the terminal device recognizes this erasure code and removes the error that was displayed until it was retransmitted. The entire screen displaying the generated image is erased as shown in FIG. 7(B). Thereafter, the terminal device decodes the subsequently sent image data and displays a normal image on an image display device such as a television receiver, as shown in FIG. 7(C).

[0009] Here, the processing of the CPU 1 in the operation procedure between the information center and the terminal device when an error occurs in the data from the information center will be explained with reference to the flowchart of FIG.

In step S11 of FIG.
determines whether there is a data reception code. If there is no data reception code, the CPU 1 determines the presence or absence of key input data including the retransmission key in step S18. If there is a data reception code in step S11, the CPU 1 determines whether there is a screen erase instruction code in the received data in step S13. In step S13, if there is a screen deletion instruction code,
In step S16, the CPU 1 instructs to erase the image memory, and in step S18, determines whether or not there is key input data including the retransmission key. Said step S13
If there is no screen erase instruction code, the CPU 1 instructs the received image data to be decoded in step S15, and determines the presence or absence of key input data including the retransmission key in step S18. do.

[0011] In step S18, if there is no key input data including the retransmission key, the CPU 1 determines in step S21 whether or not there is an error code transmitted at the end of each packet. In step S18, if there is key input data including the retransmission key,
The CPU 1 causes the data transmitting/receiving circuit 5 to perform step S2.
0, an instruction is given to transmit the code corresponding to the data input using the key to the information center, and in step S21, it is determined whether or not there is an error code transmitted at the end of each packet.

[0012] If there is no error code in step S21, the CPU 1 determines the presence or absence of a data reception code in step S11. If there is an error code in step S21, the CPU 1 instructs the image display circuit 6 to display an "X" mark on the image display screen in step S24, and then returns to step S1.
In step 1, the presence or absence of a data reception code is determined.

Here, the main steps of the CPU 1 are to determine the presence or absence of a data reception code in step S11, to determine the presence or absence of key input data including the retransmission key in step S18, and to perform the following steps in step S21. The presence or absence of an error code transmitted at the end of each packet is repeatedly determined.

As can be seen from the flow of steps above,
In step S21, when the CPU 1 recognizes that there is an error code transmitted at the end of each packet, the CPU 1 causes the image display circuit 6 to display an "X" mark on the image display screen in step S24. give instructions on what to do. The image display circuit 6 then displays an "X" mark on the image display screen. Here, when the user of the terminal device operates the retransmission key of the terminal input device and requests to obtain a normal image, the CPU 1 recognizes in step S18 that there is key input data. And CPU1 is
In step S20, the data transmitting/receiving circuit 5 is instructed to send a retransmission code to the information center. The data transmitting/receiving circuit 5 then sends the information to the information center.
Send resend code.

[0015] In such conventional communication terminal devices for displaying images, error images are corrected at the discretion of the user, so there is a possibility that the user may obtain image information without knowing that there is an error. , the user manually requests resending images, which places a burden on the user. In addition, since all the images that were displayed up to that point are erased by the retransmitted image data, it takes time to form a screen, which increases the connection time and increases the economic burden.

[0016]

[Problem to be Solved by the Invention] In the conventional image display communication terminal device as described above, error images are corrected at the discretion of the user, so it is difficult for the user to correct image information without knowing that there is an error. Moreover, since the user manually requests the retransmitted image, it places a burden on the user. In addition, when image data is resent from the information center, all the images that were previously displayed on the image display device are erased by the resent image data, so it takes time to form the image again. It takes,
The connection time between the information center and the terminal device becomes longer, and the economic burden also increases.

The present invention has been made in view of this problem, and it automatically sends a retransmission code after a certain period of time after receiving erroneous image data, and uses the retransmitted image erasure code to erase the previous image data. By displaying the resent image on the display device without erasing the contents of the image memory that was being displayed, the burden on the user is eliminated, and the economic burden is reduced because the connection time with the information center is shortened. The purpose of the present invention is to provide a lightweight image display communication terminal device.

[Configuration of the invention]

[0019]

[Means for solving the problem] An image display communication terminal device that is connected to an information center via a communication line and stores transmitted image data in a memory and then decodes it to display the image on an image display screen. means for instructing correction of the error when an error occurs in the received image data while connected to the communication line; and after a certain period of time, based on the instruction from the means for instructing the error correction, means for transmitting a retransmission code, and if this error correction is instructed, the means for transmitting the retransmission code ignores the screen erasing code added to the image data re-received; The device is equipped with means for not erasing the memory of the computer.

[0020]

[Operation] According to the present invention, when an error occurs in image data during transmission, the terminal device automatically determines the error and sends a retransmission code after a certain period of time after receiving the image data in which the error occurred. Send to the information center. Thereafter, the terminal device ignores the image erasure code and rewrites only the part where the error occurred among the image data retransmitted from the information center.

[0021]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a Videotex terminal device which is an embodiment of the present invention.

The CPU 1 is a microprocessor that decodes data sent from the information center, receives an operating clock from the oscillation circuit 9, and performs various controls according to programs stored in the ROM 2. This R
The OM2 has a built-in program that processes image data received from the information center and converts it into image data to be output to an image display device. RAM3 is CPU
1 working memory, and also includes a reception buffer for temporarily storing data sent from the information center. The chip select circuit 4 is a circuit that is controlled by the CPU 1 and selects the ROM 2 and RAM 3. The data transmitting/receiving circuit 5 is a circuit that receives image data sent from the information center and stores it in a receiving buffer in the RAM 3 according to instructions from the CPU 1. The image display circuit 6 is C
This circuit displays the image data decoded by the PU 1 on an image display device such as a television receiver (not shown). Switch 8 is a switch that instructs the operation of the present invention. The I/O port 7 is an interface that transmits the settings of the switch 8 to the CPU 1.

When the information center and the data transmitting/receiving circuit 5 are connected via a transmission medium such as a telephone line, image data is guided from the information center to the data transmitting/receiving circuit 5. The data transmitting/receiving circuit 5 receives this image data and transmits it to the CP.
Transfer to U1. The CPU 1 specifies the address of the ROM 2 via the address bus, reads out a program stored in the ROM 2 that converts image data into decoded image data, and reads the program from the RAM based on this program.
3 is used to convert the image data from the data receiving circuit 5 into decoded image data and provide the decoded image data to the image display circuit 6. The image display circuit 6 displays an image on an image display device such as a television receiver (not shown) based on the decoded image data.

[0025]Here, in the embodiment of the present invention, the operation procedure between the information center and the terminal device when an error occurs in the data from the information center will be explained with reference to FIGS. 2 and 3. . FIG. 2 is an explanatory diagram showing the operating procedure when an error occurs. FIG. 3(A) shows a screen display when an error occurs, and FIG. 3(B) shows a normal screen display after error correction.

As shown in FIG. 2, the image data transmitted from the information center is divided into a plurality of (n) packets and sent. The terminal device decodes the image data included in this packet according to the procedure explained above to form a screen. A CRC code for detecting data errors is added to the end of each packet. The terminal device uses this code to determine whether or not there is an error in the data, and if an error is detected, an "X" mark is displayed on the upper left of the image display screen as shown in Figure 3 (A), and the user of the terminal device is notified of the error. At the same time, a retransmission code is automatically sent to the information center after a certain period of time after the end of image data reception. The information center that has received this retransmission code transmits the same data as the image data to the terminal device again. Normally, there is an image memory erasure code at the beginning of the image data, but the terminal device ignores this erasure code and displays the screen where the error occurred until it is retransmitted. Only that portion is rewritten with image data obtained by decoding the subsequently sent image data, and a normal image is displayed on an image display device such as a television receiver, as shown in FIG. 3(B).

Next, the operation of one embodiment of the above configuration will be explained with reference to FIG.

In step S11 of FIG.
determines whether there is a data reception code. If there is no data reception code, the CPU 1 determines the presence or absence of key input data in step S18. Said step S11
In, if there is a data reception code, CPU1
In step S12, the time monitoring timer T is reset, and in step S13, it is determined whether there is a screen erase instruction code in the received data. If there is no screen erasure instruction code in step S13, the CPU 1 instructs to decode the received image data in step S15, and determines the presence or absence of key input data in step S18. In step S13, if there is a screen erase instruction code, the CPU 1 executes step S1.
In step 4, it is determined whether the retransmission sequence flag is on. This retransmission sequence flag is a flag that is turned on by a command from the CPU 1 when an error packet, which will be described later, is received. In step S14, when the retransmission sequence flag is off, that is, when receiving the screen deletion instruction code for the next image data after receiving normal image data without any errors, the CPU 1:
In step S16, an instruction to erase the image memory is given, and in step S18, it is determined whether or not there is key input data. When the retransmission sequence flag is on in step S14, the CPU 1 turns off the retransmission sequence flag in step S17, and determines the presence or absence of key input data in step S18.

If there is no key input data in step S18, the CPU 1 determines whether or not there is an error code transmitted at the end of each packet in step S21.
That is, it is determined whether or not an error packet has been received. In step S18, if there is key input data, C
In step S19, the PU 1 turns off the retransmission sequence flag, and in step S20, instructs the data transmission/reception circuit 5 to transmit the code corresponding to the data inputted by the key in step S18 to the information center.
In step S21, it is determined whether there is an error code transmitted at the end of each packet. This is because when the terminal device receives image data with an error, it automatically performs retransmission processing, but it is also designed to allow the user of the terminal device to perform key input operations.

If there is no error code in step S21, the CPU 1 determines the elapsed time of the time monitoring timer T in step S25. Said step S21
If there is an error code, the CPU 1 determines the setting state of the switch 8 in step S22. If this switch 8 is off, in step S24, the CPU
1 performs a process of displaying an "X" mark on the upper left of the image display screen, and in step S25 determines the elapsed time of the time monitoring timer T. If the switch 8 is on in step S22, the CPU 1 determines that an automatic retransmission operation has been instructed, and in step S23, turns on the retransmission sequence flag and displays an "X" mark at the top left of the image display screen. Then, in step S25, the elapsed time of the time monitoring timer T is determined.

This time monitoring timer T is reset in step S11 each time image data is received, and is counted for a certain period of time T by the CPU 1 after one screen is finished.

[0032] In step S25, a certain period of time T
has not elapsed, the CPU 1 executes step S11.
, the presence or absence of a data code is determined. In step S25, if the certain time T has elapsed, C
PU1 determines the retransmission sequence flag in step S26. If this retransmission sequence flag is off, C
PU1 determines the presence or absence of a data code in step S11. In step S26, if the retransmission sequence flag is on, this indicates that there was an error in the image data received immediately before, so the CPU 1
In step S27, the data transmitting/receiving circuit 5 is instructed to transmit a retransmission code to the information center, and in step S11, it is determined whether there is a data receiving code.

Here, the main steps of the CPU 1 are to determine the presence or absence of a data reception code in step S11, to determine the presence or absence of key input data in step S18, and to transmit the data at the end of each packet in step S21. Determination of the presence or absence of an error code, and step S2
The process of determining the progress of the time monitoring timer T in step 5 is repeated.

[0034]

According to the present invention, when an error occurs in image data during transmission, the terminal device automatically determines the error and, after a certain period of time after the end of receiving the image data in which the error occurred, Since the retransmission code is sent to the information center, there is no risk of the user obtaining a wrong image without knowing that an error has occurred, and the operability associated with error correction is improved, which reduces the burden on the user. Becomes lighter. Furthermore, of the image data resent from the information center, the image erasure code is ignored and only the part where the error occurred is automatically rewritten, reducing the time required to form a normal image and reducing the economic burden. will also decrease.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an image display communication terminal device of the present invention.

FIG. 2 is an explanatory diagram showing an operation procedure between an image display communication terminal device and an information center in the present invention.

FIG. 3 is a diagram showing a display example of an image display device according to the present invention.

FIG. 4 is a flowchart illustrating the operation of an embodiment of the image display communication terminal device of the present invention.

FIG. 5 is a block diagram showing a conventional image display communication terminal device.

FIG. 6 is an explanatory diagram showing an operation procedure between a conventional image display communication terminal device and an information center.

FIG. 7 is a diagram showing a display example of a conventional image display device.

FIG. 8 is a flowchart illustrating the operation of an embodiment of a conventional image display communication terminal device.

[Explanation of symbols]

1: CPU 2: ROM 3: RAM 4: Chip select circuit 5: Data transmission/reception circuit 6: Image display circuit 7: I/O port 8: Switch 9: Oscillator

Claims (1)

[Claims] 1. An image display communication terminal device that is connected to an information center via a communication line and stores transmitted image data in a memory and then decodes the image data to display the image on an image display screen. When an error occurs in the received image data while connected to the line, a means for instructing correction of this error, and after a certain period of time, transmitting a retransmission code based on the instruction from the means for instructing this error correction. and if this error correction is instructed, erase the memory of the image data by ignoring the screen erasing code added to the image data re-received by the means for transmitting the retransmission code. 1. A communication terminal device for displaying an image, comprising means for displaying an image.