JPH01245687A - Moving image encoding device and method for arranging picture element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a moving image encoding device used for videophones, video conferences, and the like.

2. Description of the Related Art Conventionally, this type of video encoding device has been equipped with an image capture unit, a video encoder, a transmission unit, and a control unit that controls the above functions. is encoded in the video encoding section and transmitted via the transmission section. In the transmission unit, the amount of codes to be transmitted per unit time is determined, and if the amount of codes exceeds the determined amount, a request is made to the control unit to drop frames. The control section that has been requested to drop frames executes frame dropping control on the image capture section.

FIG. 5 shows the configuration of a conventional moving picture encoding device.

In FIG. 5, 21 is a camera, and 22 is an image capturing section.The image captured by the camera is processed to be encoded by the image capturing section. 23 is an encoding unit that encodes the image. Reference numeral 24 denotes a transmission section, which sends the image information generated in the encoding section to the transmission path. At the same time, if encoding characteristics or frame drop control are required depending on the amount of image information, additional information is sent to the control section 25. The control section controls frame dropping for the image capturing section and controls encoding characteristics for the encoding section based on information from the transmission section.

In this way, even the conventional video encoding device described above can perform image encoding without any problems.

Problems to be Solved by the Invention However, in the conventional video encoding device described above, for example, in the first image to be encoded, all pixels are encoded, so the amount of information to be transmitted becomes large and the time required to send one screen increases. takes a long time. For this reason, there was a problem that the number of screens sent per unit time was small and the continuity of movement was lost.

The present invention solves these conventional problems and aims to provide an excellent moving picture encoding device that does not cause loss of picture continuity.

Means for Solving the Problems In order to achieve the above object, the present invention provides a thinned-out image encoding section and a switching circuit in addition to the configuration shown in FIG. To prevent continuity of motion from being lost by transmitting multiple thinned images with a reduced amount of information by thinning out pixels using a thinned image encoding unit when the image changes suddenly. This is what I did.

However, on the other hand, a new problem arises in that thinning out pixels causes deterioration in image quality. As a solution to this problem, the present invention aims to improve image quality by thinning out the peripheral part without thinning out the central part of the screen, which is visually important, and by thinning out only the color difference signal without thinning out the luminance signal. It is.

Therefore, according to the present invention, when an image changes rapidly, the continuity of the image can be maintained by sending multiple images with thinned out pixels, and when the image changes gradually, the continuity of the image can be maintained. Since encoding is performed without thinning out pixels, the problem of image quality deterioration does not occur.

Furthermore, according to the present invention, since the pixel density is high at the center of the screen, the image quality of the center of the image containing the most important image information can be improved.

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, 1 is a camera, and 2 is an image capturing section. Images taken by the camera are processed to be encoded by the image capturing section. 3 is a normal encoding unit which outputs the encoded image to (one). 4 is a thinned-out image encoding unit that generates a plurality of thinned-out images from one original image, encodes them, and outputs them to (a). 5 is a switching circuit (a), (bl) which selects the output of the encoding section to be transmitted. 6 is a transmission section, which sends the selected image information to the transmission path.

At the same time, if encoding characteristics or frame drop control are required depending on the amount of image information, additional information is sent to the control section 7.

Ru. The control unit 7 transmits frame drop control information to the image capture unit 2, encoding unit 3, thinned-out image encoding unit 4, and switching circuit 5 based on the information from the transmission unit 6, and transmits frame drop control information to the encoding unit 3. control the characteristics of

Next, the operation of the above embodiment will be explained. In this embodiment, a moving image is captured from a camera 1 to an image capture unit 2,
Furthermore, this is the encoding unit 3 and the thinned-out image encoding unit 4.
are respectively encoded.

At this time, in the case of the first image, since the amount of information to be sent is large and the transmission time is long, the switching circuit 5 is switched to the (a) side according to the instruction from the control unit 7, and multiple images are thinned out to reduce the amount of information. It is broken down into images and sent.

In the case of the second and subsequent images, the amount of information can be reduced by sending difference information, etc., so the switching circuit 5 is switched to (b) and the output of the encoding section 3 is sent to the transmission section 6.

7・ The image information is sent from the transmission section 6 to the transmission path.

On the other hand, if the moving image suddenly changes, frame drop control information is sent back from the receiving side, and the information is sent to the control unit 7 via the transmission unit 6.
The switching circuit 5 is controlled to switch to (a) by a control signal from the control section 7 to send the thinned-out image.

FIG. 2 shows an example of the thinned-out pixel arrangement method of the present invention. In Fig. 2, 10 is the image before thinning, and 11
．． 12.13 is 10 divided into 3 images,
Each pixel is thinned out to interpolate with each other. Further, as a thinning method, in addition to the above-mentioned method, it is also possible to thin out the color difference signal without thinning out the luminance signal, which is important as visual information, in addition to thinning out spatially.

FIG. 3 shows another embodiment of the method of arranging thinned pixels according to the present invention. In FIG. 3, 10 is an image before thinning, 14.15. 16 is an image obtained by dividing 10 into three images, and is an example of a thinning method in which the peripheral portion is thinned out and the central portion is left.

FIG. 4 shows an example of determining the arrangement of pixels.

As shown in Figure 4, the image is divided into multiple blocks, the coordinate origin is placed in the center of the image, and the coordinates of the center of each block are taken as the coordinates of the block. The total number of pixels in the entire image is N
s, the total number of blocks is BS, the number of pixels in each block is Nx
When y is assumed, Nxy is expressed by the following equation. N, xy-(N
s/Bs) eXpi −(X2+y2)/Ll.

In this way, according to the above embodiment in which the central part is densely arranged and the peripheral part sparsely arranged, it is possible to improve the image quality of the central part, which is the most important information in a videophone or the like.

Effects of the Invention As is clear from the above-mentioned embodiments, the present invention is configured to transmit a plurality of images with pixels thinned out for the first image to be encoded and the image with a rapid change rate. It has the advantage of providing a more natural image with respect to movement. Furthermore, in cases other than the above, since encoding is performed on images that are not thinned out, there is no possibility of deterioration in image quality.

Furthermore, as a pixel arrangement method for thinned images, screen 9 =
By arranging pixels densely in the center and sparsely in the periphery, it has the effect of improving the image quality of the visually important center.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a moving image encoding device according to an embodiment of the present invention, FIG. 2 is a diagram showing an example of the pixel thinning arrangement method of the present invention, and FIG. 3 is a diagram showing another example of the pixel arrangement method of the present invention. FIG. 4 is a diagram showing an example of a pixel arrangement determining method, and FIG. 5 is a schematic block diagram of a conventional moving image encoding device. DESCRIPTION OF SYMBOLS 1... Camera, 2... Image capture unit, 3... Encoding unit, 4 Thinned image encoding unit, 5 - Switching circuit, 6...
...Transmission unit, 7...Control unit, io...Pixel arrangement before thinning, 11.12.13.14.15.16...Example of pixel arrangement after thinning.

Claims (4)

[Claims] (1) An image capture unit that captures a moving image from an image input unit and performs preprocessing for encoding; an image encoding unit that encodes an image output from the image capture unit; a thinned-out image encoding means for thinning out a plurality of images by thinning out pixels from one outputted image and encoding each image; and an output image (a) from the thinned-out image encoding means and the image. a switching means for switching and outputting the output image (b) from the encoding means; a transmission section for sending the image sent from the switching means to a transmission path; A moving image comprising: a control means for controlling the switching means so as to output the output image (a) when the speed of image change is fast, and output the output image (b) when the speed of change of the moving image is slow. Image encoding device. (2) A method of arranging pixels in the thinned-out image encoding means, in which pixels are arranged at positions interpolated with each other among a plurality of images created by thinning out pixels from one image. (3) The pixel arrangement method according to claim (2), wherein the thinned-out image encoding means thins out only pixels targeted for color difference signals. (4) The pixel arrangement method according to claim (2), wherein in the thinned-out image encoding means, pixels are arranged densely in the central part of the image and sparsely in the peripheral part of the image.