JPH039685A - Picture encoder - Google Patents

Abstract

PURPOSE:To widely enlarge the limit of communication by encoding an input picture signal by using correlation in a picture and correlation between pictures and outputting a moving image output signal and a still picture signal. CONSTITUTION:A moving image encoder 40 and a moving image decoder 41 are connected by a high-speed line 43 for moving image and the moving image encoder 40 and a still picture decoder 42 are connected by a low-speed line 44 for still picture. Between the moving image encoder 40 and moving image decoder 41, normal moving image communication is executed, and between the moving image encoder 40 and still picture decoder 42, the communication of a still picture is executed. For encoding the still picture in the moving image encoder 40, the still picture to be transmitted to the moving image encoder 40 is fetched and encoded data gradually flow to a transmission line. Thus, the limit of the communication can be widely enlarged.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention uses a moving image encoding device of a moving image transmitting station to encode moving images and still images. The present invention relates to a moving image and still image encoding/decoding system that performs multipoint communication with a still image receiving station.

(Prior Art) Conventionally, in image communication in teleconferences, etc., moving images are communicated between video communication stations, and still image communication is performed between still image communication stations and still image communication stations. One image communication took place.

Further, communication of still images was performed between the video communication station and the video communication station using a still image mode in the video encoding device and the video decoding device.

(Problems to be Solved by the Invention) However, in image communication in conventional teleconferences, etc., the encoding processing methods of the moving image encoding device and the still image decoding device are different, so the video communication station The video communication station and the still image communication station communicate with the still image communication station in their respective closed areas, and it is impossible to communicate with both the video station and the still image communication station, which is extremely inconvenient.

In view of the above-mentioned drawbacks, a technical problem of the present invention is to provide an image encoding device capable of simultaneously performing multipoint communication between a moving image decoding device and a still image decoding device. It is.

(Means for Solving the Problems) According to the present invention, an image encoding device that encodes a single-handed image signal using correlation within a screen and correlation between screens, and outputs a video output signal and a still image output signal. But.

separating a synchronization signal from the input image signal, and converting the separated synchronization signal into a frame pulse indicating the beginning of a frame;
A line pulse that indicates the beginning of a line, and a sync separator that generates a vertical sync signal.

a first refresh means for generating a first refresh signal for performing refresh while moving by n lines every predetermined frame based on the frame pulse and the line pulse;

Write signal generating means for generating a write signal during a predetermined frame in response to a still image encoding instruction signal.

by the line pulse and the vertical synchronization signal.

Line number generating means for generating a line number that moves by n lines in each vertical synchronization period of the determined frame.

a second refresh signal that generates a second refresh signal instructing to perform intraframe encoding in the period of the vertical synchronization signal;
and a means of refreshing.

One screen of the human image signal is stored in response to the write signal, the stored image is read from an address corresponding to the line number during the vertical synchronization signal period, and the read signal is used as a still image signal. Frame memory to output.

Receive the input image signal and the still image signal.

a first selection means that selects the still image signal in the period of the vertical synchronization signal, selects the input image signal in the period other than the period of the vertical synchronization signal, and outputs one selected image signal;

and means for obtaining a prediction error signal with reduced redundancy using the selected image signal and the selected prediction signal.

quantization means for quantizing the prediction error signal and outputting a quantized signal;

means for obtaining a locally decoded signal using the quantized signal and the selected predicted signal;

a first prediction means for generating a first prediction signal using the intra-screen correlation from the locally decoded signal;

and second prediction means for generating a second prediction signal from the locally decoded signal using the correlation between the screens.

receiving the first refresh signal and the second refresh signal, selecting the second refresh signal during the vertical synchronization signal period, and selecting the first refresh signal during periods other than the vertical synchronization signal period; a second selection means for outputting the selected refresh signal;

When receiving the first and second pre-a1 signals and indicating that the selected refresh signal is a refresh line, the first prediction signal is selected, and the selected refresh signal is a refresh line. When the line indicates a line other than the line, the second prediction signal is selected.

and third selection means for outputting the selected pren1 signal.

a first code conversion means for code converting a signal other than a section of the vertical synchronization signal in the quantized signal and outputting the code-converted signal as the video output signal;

Code-converting the signal in the section of the vertical synchronization signal and the line number in the quantized signal.

There is obtained an image encoding device characterized in that it has a second code conversion means for outputting the code-converted signal as the still image output signal.

(Summary of the Invention) The invention of the present application enables communication of still images between a moving image encoding device and a still image decoding device, which was previously impossible. It performs multi-point image communication with the image communication station.

That is, as shown in FIG. 1, in order to perform multipoint communication between a moving image encoding device 40, a moving image decoding device 41, and a still image decoding device 42.

The video encoding device 40 and the video decoding device 41 are connected by a high speed line 43 for video, and the video encoding device 40 and the still image decoding device 42 are connected by a low speed line 44 for still images.
Tie it with Then, normal video communication is performed between the video encoding device 40 and the video decoding device 41, and still image communication is performed between the video encoding device 40 and the still image decoding device 42. Let's do it. To encode a still image in the video encoding device 40, a still image to be transmitted to the video encoding device 40 is captured, the captured image is encoded little by little, and the encoded data is gradually transmitted to the transmission path. It is necessary to flow it to because.

This is because the transmission path leading to the still image decoding device has a much lower transmission rate than the transmission path leading to the moving image decoding device 41, so a large amount of data cannot be sent instantaneously.

Therefore, it is necessary to encode and transmit still images little by little using a moving image encoding device.

As shown in Figure 2 (a) = (b) and (c), normally in video encoding, images are rewritten (refreshed) five times in order to remove errors caused by errors in the transmission path. is being carried out. Refreshing is performed by intra-frame coding using correlation within one screen while moving n lines at a time for each predetermined screen, and removes errors that occur in the frame memory of the decoder due to transmission path errors, and creates a new clean frame memory. Write the image into the frame memory of both the encoder and decoder. In areas other than refresh, interframe encoding is performed using the correlation between two screens.

Therefore, in encoding a still image by the video encoding device of the present invention, the refresh mode is used, and each n line is encoded by intra-frame encoding in the vertical synchronization interval, and the area other than refresh is not encoded. . By adding a line number to the encoded still image signal and sending it to the still image decoder, generation of excessive information for each screen is suppressed.

By encoding and transmitting data bit by bit in this way, a large amount of information is not generated instantly.

When encoding a still image, as shown in FIG.
A still image to be transmitted is written in the frame memory 43. As the input to the moving image encoding device 44, the output of the still image frame memory 43 is selected only in the vertical synchronization period.

N lines are encoded every vertical synchronization of the frame determined in the refresh mode. Therefore, in periods other than the vertical synchronization period, moving images can be encoded, and moving images and still images can be communicated at the same time.

The video encoding device of the present invention has a configuration as shown in FIG.
I have two predictors, IFJ device 9.

Predictors 9 and 10 are switched during normal encoding and refreshing. Furthermore, switching between a refresh signal for moving images and a refresh signal for still images is performed using the vertical synchronization signal. In video encoding, the output of the interframe predictor 9 with high encoding efficiency is selected as one normal prediction signal, and the difference from the previous picture is encoded. When performing refresh, the output of the intraframe predictor 9 is selected as a prediction signal for only that period (n lines), and intraframe encoding is performed. At this time, the intra-frame predictor 9 uses the value of the previous pixel in the screen of the input signal or a nearby pixel as the preliminary n1 signal, so it is not affected by the previous screen in which errors due to transmission path errors are accumulated. The contents of the frame memory 10 can be updated gradually with correct images.

When encoding still images, intraframe encoding is performed using vertical synchronization intervals. From the input frame memory 1 in which still images are stored, a still image signal is read out n lines at a time in accordance with the line number given from the refresh circuit 2 for each vertical synchronization period of a predetermined frame.
Perform intraframe encoding. And in the next encoded frame.

The signals of the next n lines are read out and encoded.

For each frame determined in this way, encoding is performed gradually while moving n lines at a time. A line number given from the still image refresh circuit 2 is added to the coded data at this time, and the code converter 2 converts it into an efficient code such as a Huffman code. The speed of the transmission line is then matched and the data is sent little by little over a low-speed line for still images.

The still image decoding device on the receiving side has a frame memory 52 after the intraframe decoder 51 as shown in FIG. By writing 50 lines at a time to the address of the frame memory 52 specified by the reverse code-converted line number, the area of the decoded image is gradually expanded, and it is possible to form - still images.

Since the encoded data is invalidated during the vertical synchronization interval in video encoding, a normal video decoder may be used.

(Embodiment) FIG. 6 is a block diagram showing an embodiment of the encoding device of the present invention. An embodiment of the encoding device of the present invention will be described in detail below with reference to the drawings.

The input image signal is sent to the frame memory 1 via a line 100.
．． The signal is supplied to the sync separator 2 and the switch 5. The frame memory 1 receives a write signal supplied from the refresh circuit 4 via a line 91.

When writing is instructed, the input image signal is written and the screen is stored. Further, the frame memory 1 reads still image data at an address corresponding to the line number designated via the line 90 from the refresh circuit 4 during the period of the vertical synchronization signal applied from the synchronization separator 2. The sync separator 2 separates a sync signal from the input moving image signal supplied via the line 100, and based on the separated sync signal, generates a frame pulse indicating the beginning of a frame, a line pulse indicating the beginning of a line, and Generate vertical synchronization signal. The frame pulse generated by the sync separator 2 is as follows.

It is supplied to the refresh circuit 3 via line 23.

The line pulses generated by the sync separator 2 are supplied to the refresh circuit 3 and the refresh circuit 4 via the line 24. Furthermore, the vertical synchronization signal generated by the synchronization separator 2 is transmitted via a line 21 to the frame memory 1. Refresh circuit 4. Switch 5° Switch 11. Frame memory 10. The signal is supplied to a code converter 13 and a code converter 14. The refresh circuit 3 generates a refresh signal based on the frame pulse and line pulse supplied from the sync separator 2, which performs refresh while moving by n lines every predetermined frame.

The refresh signal generated by the refresh circuit 3 is
The signal is supplied to the switch 11. Refresh circuit 4 receives a still picture instruction signal supplied via line 400 that instructs encoding of a still picture, generates a write signal over one frame, and supplies it to frame memory 1 via line 41.

The refresh circuit 4 also uses the line pulse and vertical synchronization signal supplied from the synchronization separator 2.

A line number that moves by n lines is generated for each vertical synchronization period of a predetermined frame, and is supplied to the frame memory 1 and the code converter 14 via a line 90. Further, the refresh circuit 4 generates a selection signal for performing intra-frame encoding during the vertical synchronization period and supplies it to the switch 11. The switch 5 selects a manual signal based on the vertical synchronization signal supplied from the synchronization separator 2. When the vertical synchronization signal indicates that it is a vertical synchronization period, the output signal of frame memory 1 is selected for encoding a still image, and the vertical synchronization signal indicates that it is outside the vertical synchronization period. Sometimes the line 100 is used to encode moving images.
Select the human power signal supplied via. The output signal of the switch 5 is supplied to a subtracter 6. The subtracter 6 subtracts the signal supplied from the switch 5 and the 14-1 signal supplied from the switch 12 to obtain a prediction error signal.

The output signal of the subtracter 6 is supplied to a quantizer 7.

The quantizer 7 quantizes the prediction error signal supplied from the subtracter 6. The output signal of the quantizer 7 is sent to an adder 8. The signal is supplied to a code converter 13 and a code converter 14. The adder 8 adds the quantized prediction error signal supplied from the Hk quantizer and the prediction signal supplied from the switch 12 to obtain two local posterior signals. The locally decoded signal obtained by adder 8 is supplied to intraframe predictor 9 and frame memory 10. The intra-frame predictor 9 includes an adder 8
Out of the locally decoded signals supplied from the local decoded signal, the value of the pixel 1 near the pixel to be encoded, for example, the previous pixel or the previous line, is used to generate an intra-frame side signal and is supplied to the switch 12. .

The frame memory 10 delays the locally decoded signal supplied from the adder 8 by one frame time to obtain an interframe prediction signal, but the vertical synchronization signal supplied from the synchronization separator 2 is in the vertical synchronization period. When , the writing of local decoded signals is stopped because still images are being encoded.

The inter-frame pre-Mj signal output from the frame memory 10 is
The signal is supplied to the switch 12. When the refresh signal supplied from the switch 11 indicates a refresh line, the switch 12 selects the intra-frame child A.
When the refresh signal indicates a line other than the refresh line, the output of the frame memory 10 is selected. switch 1
The predicted signal of the output of 2 is.

It is supplied to a subtracter 6 and an adder 8. The switch 11 switches the refresh signal according to the vertical synchronization signal supplied from the synchronization separator 2. In the vertical synchronization period, a still image is encoded, so the refresh signal of the refresh circuit 4 is selected, and in a period other than the vertical synchronization period, a moving image is encoded, so the refresh signal of the refresh circuit 3 is selected. . A refresh signal at the output of switch 11 is supplied to switch 12 .

The code converter 13 performs code conversion on the quantized prediction error signal supplied from the quantizer 7, but the vertical synchronization signal supplied from the sync separator 2 is in the vertical synchronization period. When this is indicated, since the still image is being encoded, code conversion is stopped and an invalid code is output. The output signal of the code converter 13 is matched with the speed of the transmission line, and is sent as a moving image output signal to a moving image decoder via the transmission line. The code converter 14 receives the quantized pre-8 in units of n lines supplied from the quantizer 7.
Code conversion is performed on the p1 error signal, but the vertical synchronization signal supplied from the synchronization separator 2 is used.

Code conversion is performed only when the vertical synchronization period is indicated, and code conversion is stopped except in the vertical synchronization period.

At this time, the line number supplied from the refresh circuit 4 is also code-converted and added to the code-converted still image signal. The output signal of the code converter 14 is matched with the speed of the transmission line and sent as a still image output via the transmission line to a still image decoder.

Next, an embodiment of the still image decoding device of the present invention will be described with reference to FIG. The still image signal encoded by the moving image encoding apparatus of the present invention is supplied from the transmission line to the inverse code converter 50 via a line 500. The reverse code converter 50 performs reverse code conversion and obtains a prediction error signal and line number in units of n lines. The prediction error signal obtained by the inverse code converter 50 is supplied to the intraframe decoder 51 via a line 5051, and the frame number is supplied to the frame memory 52 via a line 5052. The intraframe decoder 51 performs intraframe decoding using the value of a pixel 1 near the pixel to be decoded, such as a previous pixel or a previous line, as a prediction signal. The prediction function at this time is
The same intraframe encoder is used in the encoder. The still image signal decoded by the intra-frame decoder 51 is supplied to the frame memory 52. The frame memory 52 writes the intraframe decoded signal supplied from the intraframe decoder 51 to the address specified by the line number supplied from the inverse code converter 50. In this manner, the frame memory 52 gradually enlarges the area of the decoded image by writing the decoded signal to the address designated by the line number n lines at a time, thereby obtaining - still images.

When using transform coding such as orthogonal transform as an intra-frame predictor and an intra-frame decoder.

An orthogonal transformer or the like is inserted between the subtracter 6 and the quantizer 7 of the encoding device shown in FIG. At this time, the intraframe predictor 9 is deleted, and the prediction signal when the switch 12 performs intraframe coding is set to give zero.

It should be noted that the moving image decoder may be one ordinary one.

(Effects of the Invention) As explained in detail above, if the image encoding device of the present invention is used, communication between multiple points can be performed simultaneously between a moving image decoding device and a still image decoding device. Conventionally, a still image communication station and a video communication station are conducted in their respective closed areas, and the scope of communication can be greatly expanded.

When the present invention is put to practical use in this way, its effects are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing a connection relationship between a moving image decoding apparatus and a still image decoding apparatus according to the present invention, and a moving image encoding apparatus that performs multipoint communication. FIGS. 2(a), 2(b), and 2(c) are conceptual diagrams showing refreshing in video encoding according to the present invention. FIG. 3 is obtained by a moving image encoding device according to the present invention. A conceptual diagram when encoding a still image. FIG. 4 is a block diagram of a moving picture encoding device according to the present invention. FIG. 5 is a block diagram of an embodiment of a still image decoding device on the receiving side. FIG. 6 is a block diagram of an encoding device according to an embodiment of the present invention. In the figure, 1, 10.52...frame memory 2.
-・Sync separator, 3.4... Refresh memory. 5.11.12...Switch, 6...Subtractor, 7.
... Quantizer, 8... Adder, 9... Intraframe predictor, 13.14... Code converter, 50... Inverse code converter, 51... Intraframe decoder.

Claims (1)

[Scope of Claims] 1. An image encoding device that encodes an input image signal using correlation within a screen and correlation between screens, and outputs a video output signal and a still image output signal, wherein the input image a sync separator that separates a synchronization signal from a signal and generates a frame pulse indicating the beginning of a frame, a line pulse indicating the beginning of a line, and a vertical synchronization signal based on the separated synchronization signal; a first refresh means for generating a first refresh signal for performing refresh while moving by n lines every predetermined frame based on the line pulse; write signal generating means for generating a write signal during a specified frame; and a line generating means for generating a line number that moves by n lines in each vertical synchronization section of the predetermined frame according to the line pulse and the vertical synchronization signal. a number generating means; and a second refresh signal that generates a second refresh signal instructing to perform intra-frame encoding in the section of the vertical synchronization signal.
refreshing means for storing one screen of the input image signal in response to the write signal, reading out the stored image from an address corresponding to the line number during the interval of the vertical synchronization signal, and reading out the stored image from an address corresponding to the line number in the interval of the vertical synchronization signal; a frame memory that receives the input image signal and the still image signal, selects the still image signal for the period of the vertical synchronization signal, and selects the still image signal for the period other than the period of the vertical synchronization signal; first selection means for selecting a signal and outputting the selected image signal; means for obtaining a prediction error signal with reduced redundancy using the selected image signal and the selected prediction signal; quantization means for quantizing a prediction error signal and outputting a quantized signal; means for obtaining a locally decoded signal using the quantized signal and the selected prediction signal; and a means for obtaining a locally decoded signal from the locally decoded signal. a first prediction means for generating a first prediction signal using the correlation within the screen; and a second prediction means for generating a second prediction signal using the correlation between the screens from the locally decoded signal. , receives the first refresh signal and the second refresh signal, selects the second refresh signal for the period of the vertical synchronization signal, and selects the first refresh signal for the period other than the period of the vertical synchronization signal. a second selection means for selecting and outputting the selected refresh signal; and receiving the first and second prediction signals, when the selected refresh signal indicates that the refresh line is the refresh line; A first prediction signal is selected, and when the selected refresh signal indicates a line other than the refresh line, the second prediction signal is selected, and the second prediction signal is output. and a first code conversion means for code converting signals other than the vertical synchronization signal section in the quantized signal and outputting the code converted signal as the video output signal. , a second code conversion means for code converting the signal in the section of the vertical synchronization signal and the line number in the quantized signal, and outputting the code-converted signal as the still image output signal; An image encoding device comprising: