JPS62269488A - Picture encoding transmission equipment - Google Patents

Abstract

PURPOSE:To obtain an inexpensive device in which performances required for both a moving image and a still picture are satisfied, by performing encoding with picture elements fitted respectively, at an encoding part common for the moving image, and the still picture. CONSTITUTION:The decoding operation of the moving image at a decoding part is performed as usual, but at the time of decoding the still picture, a decoding signal is fetched in a still picture frame memory 21 temporarily. At the time of transmitting a double circled picture element by an encoding part at a still picture transmission side, a still picture controller at the decoding part of a reception side controls so that the decoding signal is written at the position of the double circled picture element in the frame memory 21. It is possible to make a whole image roughly display at an early time of transmission by performing an interpolation processing, even when only the double circled picture element is transmitted to the decoding part at the reception side. In such a way, it is possible to obtain the device manufactured at low cost, and in which superior picture quality, and performances for both the moving image, and the still picture, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image encoding and transmitting device used for communication conferences and the like.

[Conventional technology]

FIG. 4 is a block diagram showing the configuration of a conventional image encoding and transmission device that transmits moving images and still images. The image signal (to) is a video encoding/decoding device (hereinafter abbreviated as codec) that encodes the video signal (5) and decodes the video encoded data into the video signal 03.3 is the video encoder Data, (to) is a transmission control unit for connecting the video codec (to) and still image codec (to) to the game, C
a11 is the multiplexed data exchanged by the transmission control unit (to), 02 is the video signal decoded by the video coder, 0 is the monitor that displays the video signal image, 041 is the still image camera, (to) is a still image signal, (to) is a still image coden that encodes and decodes the still image, is still image encoded data, is a still image signal, and CII is a monitor that displays the still image signal (to).

FIG. 5 is a block diagram showing an example of a video encoding section of a conventional image encoding and transmitting device. (4) is an input signal sequence that is a blocked coding unit, (5) is a dynamic vector quantizer, (61 is a DVQ index, and (7) is a DVQ output vector. , C is a filter that prevents noise accumulation, (9) is the DvQ output vector that has passed through the filter, 01-digit subtractor,
til+ is an inter-frame difference vector, 03 is an adaptive vector quantizer, and (13 is adaptive vector quantization (hereinafter abbreviated as AVQ) encoding information.

α4 is A, V Q, output vector, Q51 is adder, [+61 is local decoding vector, field memory for the number of pixels of αDFi video, 0 seconds is delayed previous frame vector.

FIG. 6 is a block diagram showing an example of a decoding section of a conventional image encoding and transmitting device, where (6) is a DVQ index,
is a dynamic vector quantization supervising/decoding unit, @ is a digital filter, (9) is a DVQ output vector that has passed through the filter, and the other side is AVQ encoding information.

09 is an adaptive vector quantizer decoding unit, α field is a locally decoded interframe difference vector, and t19 is an adder.

(Iff is a local decoding vector, 071 is a field memory for the number of pixels of a moving image, cl, i is a deblocking circuit that scan-converts a blocked signal sequence in the raster direction, and u4 is a moving image output signal sequence.

Next, the operation will be explained. In Fig. 4.

The video camera (A) converts the video into an electrical signal to obtain a video signal (2'6).Video signal (5)
is compressed and encoded by the video codec Ca81 and sent to the transmission system 1 (to) as video encoded data (to).

On the transmission side, both parts multiplex the video encoded data with other data to be transmitted, and transmit the multiplexed data Cl11.

At the same time, it receives the multiplexed data sent from the game and distributes it to nine. If it is obtained from the video encoded data (multiplexed data cl1 received by 21), it is sent to the video codefuku (example), and the video signal 02 from the game is decoded and displayed on the video monitor (c). .

On the other hand, the still image codec (1) normally does not perform any encoding operation, and encodes the still image 1 signal (c) from the still image camera only when it is safe to transmit still images. The still image encoded data CAN is sent to the transmission control unit (to). In general, still image encoding involves a large number of subframes compared to moving images, and it is not possible to encode a single still image using the correlation between consecutive frames like in moving images. The amount of encoded image data is considerably larger than the encoded data of one screen of video.Therefore, when still image transmission starts.

The transmission control unit temporarily suspends transmission and reception of video encoded data in order to complete still image transmission in the shortest possible time.

In the block diagram of the video codec encoding unit shown in FIG.
The input vector (4) is a block of ×n strokes.

In the dynamic vector quantizer (5), the human vector +411''i is compared with the dynamic code table consisting of the previous frame signal u81 etc. read from the field memory αD, and the input vector (4) is displaced around the in-screen position. It is quantized into the previous frame vector at the position of the target, and the DVQ index (6), DVQ, and output vector (force) corresponding to the displacement are obtained.

The DVQ output vector (power) is smoothed by a digital filter Q to prevent accumulation of quantization noise.

The DVQ output vector (9) smoothed by the filter enters the subtractor and is subtracted from the input vector (4).

Obtain the interframe difference vector uIl. The inter-frame difference vector (IO is subjected to adaptive processing such as motion detection and mean value separation normalization in an adaptive vector quantizer a2.

AVQ output vector 1141 and AVQ such as index
Code encoding information is used. The AVQ output vector is added to the DVQ output vector (9) smoothed by the filter in an adder O9 to form a locally decoded vector 0υ.

is written to the corresponding location in field memory 07).

The contents of field memory (171) are quoted by DVQ when encoding the 0th frame.
VQ, index (6) is variable length coded.

The transmission fti control unit sends out the data as transmission data, but in order to keep the amount of transmitted information constant, if the amount of information generated is large, frames to be encoded are thinned out and frame dropping control is performed.

In the decoding unit block diagram of FIG. 6, DVQ.

The index (6), AVQ, and encoded information o3i are decoded into a moving image signal sequence (2). First, the DVQ index (61) enters the DVQ decoding unit (to) and the digital filter Ca, and the previous frame vector at a position displaced according to the DVQ index (6) from the corresponding position of the previous frame decoded image in the field memory (lη) is read. Served.

It is smoothed by a digital filter Qω. on the other hand.

AVQ, encoding information ([31id AVQ decoding capital 09 decodes the inter-frame difference locally decoded vector Q41, adds it to the previous frame vector (9) smoothed by a filter in the adder u9, and generates the locally decoded vector (in order) is obtained.

The local decoding vector Uυ is placed in the corresponding position of the feed memory 07) for decoding the next frame! j: Being drawn into.

The above is necessary for the operation of video codecs, but video codecs reduce the number of pixels in order to encode moving images within a limited amount of information.

On the other hand, encoding still images and written images requires higher resolution, and it is difficult to encode moving images and still images using the same number of pixels. Therefore, when transmitting moving images and still images, it is necessary to prepare a still image codec that is independent of the moving image codec.

[Problem that the invention seeks to solve]

Since the conventional image encoding and transmitting apparatus is configured as described above, it is necessary to have a moving image codec and a still image codec independently, which results in an increase in cost.

! If one encoder is used for both codecs, the number of pixels in the video is too large, and the amount of information generated is large.

There were problems with limited circuits, such as the inability to make smooth movements, and the lack of resolution for still images, resulting in dissatisfaction with performance.

This invention was made to solve the above-mentioned problems, and by using a common encoding unit for video and still images, it is possible to reduce the cost (but also improve image quality and performance for both video and still images). The purpose is to obtain a good image encoding and transmitting device d.

[Means for solving problems]

In the image encoding and transmission device according to the present invention, a common encoding unit is used for encoding moving images and still images, and the resolution of still images is set to twice that of moving images horizontally and twice vertically. , field memories in the interframe coding/decoding loop are provided for the number of moving picture pixels, and frame memories for the number of still picture pixels are provided only outside the decoding loop of the decoding section.

[Effect]

The image encoding and transmitting device of the present invention operates in the same way as the conventional method when encoding a moving image, but when encoding a still image, it skips one pixel in the horizontal direction and skips one pixel in the vertical direction. The first sub-sample image is transmitted using intra-frame coding, the quantization distortion is converged using inter-frame coding, and the remaining sub-sample images are then transmitted using inter-frame coding. By encoding and transmitting the sub-sample images, a still image with four times the number of pixels as a moving image is transmitted.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of an encoding section of an image encoding and transmitting apparatus according to the present invention. In Fig. 1, (1) is the input signal series that is the digitalized signal from the camera, (
2) is a blocking circuit that blocks and outputs a signal scanned in one direction.

(3) is a still image controller that controls blocking during still image transmission; and (4) Id has been blocked. (5) is a dynamic vector digitizer, (61 is a DVQ index, (7) is a DVQ output vector, (8) is an adaptive filter whose characteristics change depending on the DVQ index, (9) is an adaptive DVQ passed through the filter (8), output vector, (II is the subtracter H inter-frame difference vector, 02 is the adaptive vector quantizer, a-yu is the AVQ encoding information, C4 is the AVQ, output vector, (19 is adder, ne is the local decoding vector.

An is a field memory corresponding to the number of pixels of the moving image, and 0 sand is a delayed previous frame vector.

FIG. 2 is a block diagram showing an example of the decoding section of the image encoding and transmitting apparatus according to the present invention, and (6) is a DVQ.

index, (2) is a dynamic vector quantizer decoding unit, (river is an adaptive filter whose characteristics change depending on the DVQ index, (9) is a DVQ output vector that has passed through the adaptive filter (8), Hake AVQ, encoding information , a9
is the adaptive vector quantizer decoding unit, θ is the locally decoded interframe difference vector, a is the adder, haze is the locally decoded vector, an is the field memo 1 for the number of pixels in the video, Q11 is the still image frame memory with a capacity for the number of pixels (four times that of the video), (a) is the static Ryogawa force signal sequence, (3)
is a still image controller, C231 is a deblocking circuit that performs scanning conversion of blocked vectors in the raster direction, and I24 is a video output signal series.

Next, the operation will be explained.

In FIG. 1, in the case of encoding a moving image, the same operation as in the conventional example is performed. However, in this embodiment, the filter in the interframe coding and decoding loop includes DVQ.

An adaptive filter (8) that adaptively changes the smoothing characteristic according to the index (61) is used. This operation is expressed by the following equation when the filter output of the pixel X is ga in the pixel durability shown in Figure 3. It will be done.

Here, the control variable α is expressed by a temporal equation in which U is the horizontal component and V is the vertical component of the movement vector indicated by the DVQ index.

. Engineering, -a (Iul+IVI) 8 is a positive constant determined by the continuous nature of the image.

Also, the above formula uses the absolute value distance of the movement vector, but it is 0
The following formula may also be used.

. It goes without saying that the adaptive filter is also used in the video decoding section.

On the other hand, in the case of still image encoding, the following operation is performed.

The number of encoded pixels for still images is t in both horizontal and vertical directions compared to moving images.
Since it is multiplied by i2, the double circle and circle in Figure 3.

The pixels corresponding to the triangular and square positions are encoded separately. In FIG. 3, it is assumed that the encoding process of the moving image is the position of the double light mark. In the case of still image encoding, first block only the pixels of double light,
Transmission is performed after intraframe encoding. When this is completed, interframe coding is performed using the quantized signal written in the field memory Q, 71 as a predicted value. In the case of still images, the input signal (1) does not change during interframe encoding, so interframe encoding repeatedly encodes adaptive vector quantization errors. After several cycles of interframe encoding, the decoded values of the pixels of double light eventually converge. When the pixel values of the double light converge to a certain degree, the still image controller (3) issues an instruction to the blocking circuit to collectively form a block of pixels marked with circles in FIG. The pixels are circled.

Encoding is started using the decoded value of the 211th circle pixel encoded immediately before as the predicted value. When the decoded value of the pixel marked with a circle eventually converges, the pixel coding of the triangular mark is performed, and after that, the pixel marked with the square mark is coded, and so on, and four sequences are performed at number 1111.

The decoding of a moving image in the decoding section is the same as the operation of the conventional example, but in the case of decoding a still image, the decoded signal is carried and taken into a still image frame memory. When the encoding unit on the still image transmitting side encodes and transmits the double light pixels shown in Fig. 3, the still image controller of the decoding unit on the receiving side (
3) is controlled so that the decoded signal is written at the pixel position of the double light of the still image frame memo IJCa1l. Even if only the pixels of the double light are transmitted to the receiving side decoding unit, by performing interpolation processing, it is possible to display a rough overall image at an early point in the still image transmission.

In the above embodiment, even during still image transmission, the adaptive filter
Although controlled by the Q index.

During still image transmission, it is better to perform other controls such as the following.

First, when the pixels of the double light in Fig. 3 are intra-frame encoded, the weighting coefficient of the adaptive filter is decreased, and when inter-frame encoding is performed, the speed of inter-frame encoding increases. α is increased each time, and α is controlled to become “1” when interframe encoding of pixels of double light is completed.

Next, interframe encoding of the pixels marked with circles in FIG. 3 starts, but at this time α is again made small and gradually approaches 1".

Furthermore, in the above embodiment, it is assumed that the input of the camera displaying the still image does not change while the still image is being transmitted.
If a still image frame memory is prepared at the entrance of the encoding section, the camera input can change once the still image is loaded into the memory. If it is shared with the frame memory, the increase in hardware will be small.

〔Effect of the invention〕

As described above, according to the present invention, the single-image encoding/transmission device is configured such that the encoding section for moving images and still images performs encoding with the appropriate number of pixels for each. Both have the effect of providing an inexpensive device that satisfies the required performance.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the encoding section of the image encoding and transmitting device according to the present invention, FIG. 2 is a block diagram showing an example of the decoding section of the image encoding and transmitting device according to the present invention, and FIG. FIG. 4 is an explanatory diagram showing the arrangement of still image coding pixels of the image coding and transmitting device according to the present invention. FIG. 4 is a block diagram showing a configuration example of a conventional image coding and transmitting device that transmits moving images and still images. FIG. 6 is a block diagram showing an example of an encoding section of a conventional image encoding and transmitting device. FIG. 6 is a block diagram showing an example of a decoding section of a conventional image encoding and transmitting device. FIG. FIG. 3 is an explanatory diagram of the operation of an adaptive filter used in the encoding/transmission device. In the figure, +11 is an input signal sequence, (2) is a blocking circuit, (3) is a still image controller, (4) is an input vector, (5] is a dynamic vector quantizer, +6
11dDVQ index, (7) is the DVQ output vector. (8) is the adaptive filter, (9j is the DV passed through the filter
Q. Output vector, aQ is a subtracter, aU is an inter-frame difference vector, o2 is an adaptive vector quantizer, α311″i
AVQ encoding information, α core is AVQ, output vector, α
9 is an adder, the mark is a locally decoded vector, aη is a field memo 1, tllj is a previous frame vector, Ql is an adaptive vector quantizer decoding unit, t2Ij is a dynamic vector quantizer decoding unit, ell is a still image frame Memory, ■ is a still image output signal series, and C23 is a deblocking circuit. @ is the video output signal series, (to) is the digital filter. c7e is a video camera, or video signal, - field is a video codec, V! I is video encoded data, (, 3 is the transmission control unit, l3111'i multiplexed data, C33 is the video signal, (g) is the video monitor, (b) is the still image camera, (9 is the still image) signal, (to) still image codec,
0D is still image encoded data, (to) is still image signal,
C31 is a still image monitor. In addition, in FIG. 1, the same reference numerals indicate the same or equivalent parts. ○ku○〈〈〈〈 ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○○

Claims (2)

[Claims] (1) A blocking circuit that blocks an image signal sequence input in raster direction scanning order into encoding processing unit blocks of m×n (m and n are integers) pixels and uses the blocks as input vectors, and an image of at least one frame or more earlier. A field memory that stores one field, and a set of output vectors that are read out by blocking signal sequences at or around the encoding target position from the field memory, and one of the output vectors that is most similar to the input vector. A dynamic vector quantizer that obtains one as a dynamics vector quantization (hereinafter abbreviated as DVQ) output vector and uses the index (label) of the DVQ output vector as an encoded output, and a smoothing process for the DVQ output vector. A digital filter that prevents accumulation of vector quantization noise, a subtracter that obtains a difference signal between the input vector and the digital filter output, and a vector quantum an encoding unit comprising an adaptive vector quantizer that performs quantization, an adder that adds the output of the digital filter and the adaptive vector quantization output vector to obtain a locally decoded vector, and one field of a decoded image at least one frame before. a field memory for storing the information, an adaptive vector quantizer decoding unit that decodes the adaptive vector quantization coded information encoded by the adaptive vector quantizer and reproduces the decoded frame difference vector, and the dynamic vector quantizer. a dynamic vector quantizer decoding unit that decodes the DVQ index encoded by the quantizer, reproduces the movement vector, and controls the read position of the field memory; and the field that is read out according to the movement vector. A digital filter connected to the output of the memory, an adder that adds the decoded inter-frame difference vector and the output of the filter, and a deblocking circuit that converts the locally decoded vector that is the output of the adder into a raster scanning image signal sequence. A decoding unit comprising an image signal encoding/decoding unit constitutes a basic unit for encoding and decoding an image signal. Take every other pixel horizontally and vertically, and every other line, and create subsample blocks at the same intervals as the pixel interval of the video.
Shift the pixels to be blocked in four ways so that all pixels of the still image are encoded, and use the above image signal encoding/decoding basic unit to intra-frame encode the first sub-sample image signal. After transmission, the intra-frame encoded image signal is used as a predicted signal to perform inter-frame encoded transmission, and the remaining sub-sampled image signals are also inter-frame encoded using the inter-frame encoded image signal as a predicted value. an encoding-side still image controller that performs transmission and instructs the above-mentioned interframe encoding to be repeated for several frames on the same sub-sampled image signal to improve image quality; and the above-mentioned locally decoded output vector in the decoding section. The first sub-sample image signal is obtained by intra-frame decoding during still image decoding, and written to the corresponding position in the still image frame memory, and then written to the decoded image filled memory. Interframe decoding is performed using the intraframe decoded image signal as a prediction signal, and interframe decoding is performed on the remaining sub-sampled image signals using the interframe decoded signal as a prediction value. An image encoding and transmitting apparatus comprising: a still image controller on a decoding side that instructs to repeat decoding for several frames and write the decoding to a corresponding position in the still image frame memory. (2) The digital filter that prevents the accumulation of noise has D according to the magnitude of the amount of motion indicated by the DVQ index.
In order to strengthen the degree of smoothing processing for the VQ output vector, the weighting coefficient α of the filter is varied, and the target pixel is
Image encoding according to claim 1 using a motion adaptive filter in which the filter output of the target pixel is the sum of the multiplied value and the value obtained by multiplying (1-α) the average value of the surrounding four pixels. Transmission device.