KR101625910B1 - Method and device for image processing by image division - Google Patents

Abstract

An image processing method and apparatus using image segmentation capable of minimizing deterioration of image quality due to an error in a transmission path and increasing compression efficiency in performing compression and decompression of a video signal using a plurality of processors are provided. An image processing method using image segmentation according to an embodiment of the present invention includes dividing an image frame into a plurality of sub-blocks having a predetermined pixel size, sampling pixels at the same position within a predetermined number of sub-blocks Constructing a plurality of macroblocks, and constructing a plurality of slices by dividing the plurality of macroblocks according to locations in subblocks of the sampled pixels.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and an apparatus for image processing using image segmentation,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method and apparatus using image segmentation, and more particularly, to a technique of dividing an image frame in order to process a high-resolution image in parallel using a multi-processor.

Screen resolutions of mobile devices such as mobile phones, PMPs, and PDAs are steadily increasing. In recent years, smart phones and tablet PCs have enabled high-quality video services on mobile devices. With the spread of digital TVs, the screen resolution is 1920 x 1080 or more, that is, full-HD household TVs are becoming popular, and the frame rate is also increasing. Furthermore, UHDTV (Ultra HDTV) having a resolution of 4K or 8K (for example, 7680 x 4320) based on the horizontal of the screen has been attracting attention as a next generation TV.

Image compression techniques capable of increasing the compression efficiency of an image with increasing resolution of a display device have been developed and used. The amount of computation for compressing and restoring an image increases with the increase of the screen size and the frame rate.

In order to reduce power consumption while processing a large amount of computation, a multicore processor having a plurality of CPUs on one chip has been developed and is widely used in PCs and notebooks, and is also used for smartphones and tablet PCs .

In order to efficiently compress image data, a conventional image compression method divides an original image into a plurality of blocks having a predetermined size, and one block includes adjacent pixels on the screen. For example, in the H.264 / AVC standard, the image is divided into macroblocks. The macroblock is composed of one 16 × 16 Luminance sample block and two chrominance sample blocks. (The size of the color difference sample block may vary depending on the format of the input image). FIG. 1 is a diagram illustrating a method of dividing an image into 16 × 16 macroblocks according to the prior art. In this manner, the entire picture is divided into macroblocks of uniform size, and encoding / decoding or decoding is performed on a macroblock-by-macroblock basis.

In addition, the conventional image compression standard uses a method of dividing an original image into a plurality of slices and encoding the original image in order to prevent a decoded image from being degraded due to errors in a transmission path, Do not propagate to other slices. For example, as shown in FIG. 2A, in the MPEG-4 standard, a method of constructing slices by grouping several macroblocks in a raster scan order is used. In the H.264 / AVC standard, a slice is constructed in an arbitrary order irrespective of the scanning order as shown in FIG. 2B. As shown in FIG. 2C, successive macroblocks are alternately arranged in different slice groups Slice a method of allocating macroblocks belonging to an arbitrary square area to different slice groups as shown in FIG. 2D, and the like.

Meanwhile, the method of dividing an image into a slice or a slice group as described above can be used not only to reduce the influence of errors in transmission and decoding of an image, but also to perform encoding or decoding of an image through a plurality of processors It is possible. 3 is a diagram illustrating a method of dividing one image into a plurality of slices and simultaneously encoding them in a plurality of image encoding processors and combining them into one bit stream.

However, when the conventional method as described above is used, compression information of adjacent slices can not be used, so there is a disadvantage in that the compression efficiency is lower than that when a whole screen is encoded into a single slice. If an error occurs in the transmission path, There is a problem that image quality deterioration is inevitable in a certain area. Also, when the continuous macroblocks are allocated to different slice groups as in the method of FIG. 2C or the like, it is possible to distribute image deterioration due to errors to the entire screen, but there is a problem that the compression efficiency is lowered further .

Disclosure of Invention Technical Problem [8] The present invention has been proposed in order to solve the above-described problems, and it is an object of the present invention to provide an image compression apparatus and a compression / decompression method capable of minimizing deterioration in image quality due to errors in a transmission path, And an object thereof is to provide an image processing method and apparatus using image segmentation.

According to an aspect of the present invention, there is provided an image processing method using image segmentation, the method comprising: dividing an image frame into a plurality of sub-blocks having a predetermined pixel size; And constructing a plurality of slices by dividing the plurality of macroblocks according to positions in the sub-blocks of the sampled pixels.

The method may further include encoding the plurality of slices in parallel using a plurality of image encoding processors, and combining the encoded data to generate a bitstream.

According to another aspect of the present invention, there is provided an image processing method using image segmentation, comprising: dividing an image frame into a plurality of sub-blocks having a predetermined pixel size; calculating an average value of pixels of each of the plurality of sub- And constructing an average value slice with pixels having an average value.

The method includes the steps of: constructing a plurality of macroblocks by sampling pixels located at the same position within a predetermined number of subblocks; dividing the plurality of macroblocks according to locations in subblocks of the sampled pixels, And calculating a difference value between the pixels included in each of the plurality of slices and the pixels included in the average value slice to construct the plurality of slices as the difference values.

The method may further include encoding the average value slice and a plurality of slices including the difference values in parallel using a plurality of image encoding processors, and combining the encoded data to generate a bitstream.

In the encoding step, information on positions in subblocks of pixels constituting each slice may be recorded in a slice header.

An image processing apparatus using image segmentation according to an embodiment of the present invention divides an image frame into a plurality of sub-blocks having a predetermined pixel size, samples pixels at the same positions in a predetermined number of sub-blocks, And a plurality of image encoders for encoding the plurality of slices in parallel, each of the plurality of macroblocks being divided into a plurality of sub-blocks, A multiprocessor including a processor, and a data combining unit for combining the encoded data to generate a bitstream.

The image divider may further comprise an average value slice with pixels having the average value by calculating an average value of the pixels of each of the plurality of subblocks. The average value slice may include pixels included in each of the plurality of slices, The difference values with the included pixels may be calculated and the plurality of slices may be configured with the difference values.

The plurality of image encoding processors may encode the average value slice and a plurality of slices composed of the difference values in parallel.

According to the present invention, an image is divided and encoded and decoded so that neighboring pixels are contained in different slices, so that even if an error occurs in some slices during data transmission, It is possible to remarkably reduce noticeable picture quality deterioration through the transmitted peripheral pixels.

Further, there is an effect that the compression efficiency is improved as compared with the case where the same number of slices are divided by the conventional technique.

Also, even if only one of a plurality of slices is decoded, a reduced whole image can be obtained, and spatial scalability can be provided more effectively.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a conventional image dividing method; Fig.
2A to 2D are diagrams illustrating various methods of dividing an original image into a plurality of slices.
3 illustrates a method of encoding an image using a plurality of processors.
4 is a flowchart of an image processing method using image segmentation according to an embodiment of the present invention.
5 is a diagram for explaining in detail a method of dividing an image according to the embodiment of FIG.
6 is a flowchart of an image processing method using image segmentation according to another embodiment of the present invention.
7 is a configuration diagram of an image processing apparatus using image segmentation according to an embodiment of the present invention.

The above and other objects, features, and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, which are not intended to limit the scope of the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 is a flowchart of an image processing method using image segmentation according to an embodiment of the present invention, and FIG. 5 is a diagram for explaining the image segmentation method according to the embodiment of FIG. 4 in detail.

Referring to FIGS. 4 and 5, an image processing method using image segmentation according to an embodiment of the present invention includes dividing an image frame into a plurality of sub-blocks having a predetermined pixel size (S401) (S403) of sampling a plurality of macroblocks by sampling pixels at the same position in the block, and constructing a plurality of slices by dividing the plurality of macroblocks according to positions in the sub-blocks of the sampled pixels Step S405. The method may further include a step (S407) of encoding a plurality of slices in parallel using a plurality of image encoding processors, and a step (S409) of combining the encoded data to generate a bitstream.

In this embodiment, it is assumed that one macroblock has a size of 16 x 16 pixels. However, it is obvious that the size of such a macroblock may vary depending on the format and resolution of the image.

In step S401, the image is divided such that M x N pixels of the original image constitute one sub-block. In this embodiment, M = N = 2, and the positions of four adjacent pixels in one sub-pixel are expressed as a, b, c, and d, respectively, as shown in FIG.

In step S403, a plurality of macroblocks are configured by sampling pixels located at the same positions in 16x16 sub-blocks. That is, when sampling is performed in the horizontal direction by M: 1 and in the vertical direction by N: 1, pixels are selected one by one in the horizontal and vertical directions from the condition of M = N = 2, The pixels at positions b, c, and d are separated into different macroblocks. In this way, the pixels at the position a are grouped together and the macroblock a0, a1, ... And the pixels at positions b, c, and d are grouped together to form macroblocks b0, b1, ... , c0, c1, ... , d0, d1, ... .

In step S405, a slice is composed of a plurality of macroblocks composed of pixels located at the same positions. That is, the macroblocks a0, a1, ... And the slice A is constituted, and the slices B, C and D are constituted similarly.

Subsequently, in step S407, the slices A, B, C, and D are simultaneously encoded in parallel using a plurality of image encoding processors, and the encoded data is combined in step S409 to generate one bit stream. Each slice can be combined and transmitted without restriction of order.

In this case, in order to enable accurate decoding of the bitstream, it is possible to record, in the slice header, information on the positions of the pixels included in each slice in the sub-block in the encoding process. Alternatively, the values required for the slice header can be eliminated by predefining the values of M and N and defining the slice transmission order in advance. In the subsequent decoding process, the decoded result of each slice can be rearranged so that the pixels included in each slice can be displayed at the correct positions on the screen using the recorded information or the predefined order.

According to the present invention, spatial scalability can be effectively supported in one bitstream. That is, according to the above embodiment, since each slice has uniform spatial information about the image, it is possible to obtain a reduced full screen even if only one of the slices A, B, C, and D is decoded.

6 is a flowchart of an image processing method using image segmentation according to another embodiment of the present invention.

Referring to FIG. 6, an image processing method according to another exemplary embodiment of the present invention includes dividing an image frame into a plurality of sub-blocks having a constant pixel size (S601), calculating an average value of pixels of each of the plurality of sub- A step S603 of constructing a plurality of macroblocks by sampling pixels at the same position within a certain number of subblocks, (S607) and a plurality of macroblocks are divided according to the positions in the sub-blocks of the sampled pixels to form a plurality of slices. The difference value between the pixels included in each of the plurality of slices and the pixels included in the average value slice is And constructing the plurality of slices into difference values (S609). In addition, the method may further include a step (S611) of encoding a plurality of slices composed of an average value slice and difference values using a plurality of image encoding processors in parallel (S611), and combining the encoded data to generate a bitstream (S613) .

The present embodiment is an example in which the spatial scalability is further developed in the embodiments of FIGS. 4 and 5, and is a separate average value slice consisting of pixels having an average value of pixels included in each sub- And the remaining slices may comprise difference values from the pixels included in the average value slice to improve the encoding efficiency. In this case, in the decoding process, only a mean value slice is decoded to obtain a restored image of a small size, and if the remaining slices are further decoded, an image of the same size as the original can be obtained.

7 is a configuration diagram of an image processing apparatus using image segmentation according to an embodiment of the present invention.

Referring to FIG. 7, an image processing apparatus using image segmentation according to an exemplary embodiment of the present invention includes an image division unit 701, a multi-processor 703, and a data combination unit 705.

The image divider 701 divides an image frame into a plurality of sub-blocks having a predetermined pixel size, samples pixels at the same positions in a predetermined number of sub-blocks to form a plurality of macro blocks, A plurality of slices can be constructed by dividing the block according to the position in the sub-block of the sampled pixels.

In addition, the image divider 701 may calculate an average value of the pixels of each of the plurality of sub-blocks, and further configure one average value slice as the pixels having the calculated average value. In this case, A plurality of slices may be configured as calculated difference values by calculating the difference value between the pixels and the pixels included in the average value slice.

The multiprocessor 703 includes a plurality of image encoding processors P_A, P_B, ..., P_X for simultaneously encoding a plurality of slices in parallel. The plurality of image encoding processors P_A, P_B, ..., P_X may record information on positions in subblocks of pixels constituting each slice in the slice header during encoding. The multiprocessor 703 may be implemented in the form of a multicore processor in which a plurality of cores exist in one chip and perform different operations in parallel.

The data combining unit 705 combines data encoded in parallel to generate one bit stream. The order of combining the parallel data can be determined in an order determined according to the specification of the image or the like, or arbitrarily.

The more detailed functions and the effects of the respective configurations are the same as those described with reference to FIGS.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention.

Claims (14)

Dividing an image frame into a plurality of sub-blocks having a predetermined pixel size;
Constructing a plurality of macroblocks by sampling each pixel corresponding to the same position in each sub-block of the plurality of sub-blocks; And
Constructing a plurality of slices by classifying the plurality of macroblocks based on positions of the sampled pixels in subblocks;
The image processing method comprising:
The method according to claim 1,
Encoding the plurality of slices in parallel using a plurality of image encoding processors; And
Combining the encoded data to generate a bitstream
The image processing method comprising the steps of:
3. The method of claim 2,
And the encoding step records information on positions in subblocks of pixels constituting each slice in a slice header
Image Processing Method Using Image Segmentation.
The method according to claim 1,
Wherein the macroblock has a size of 16 x 16 pixels
An image segmentation method of a video signal.
Dividing an image frame into a plurality of sub-blocks having a predetermined pixel size;
Calculating an average value of pixels of each of the plurality of subblocks;
Constructing an average value slice with pixels having the average value;
Forming a plurality of macroblocks by sampling respective pixels corresponding to the same position in each sub-block of the plurality of sub-blocks;
A plurality of macroblocks are classified into a plurality of slices based on positions of the sampled pixels in subblocks, and a difference value between pixels included in each of the plurality of slices and pixels included in the average value slice Calculating the plurality of slices as the difference values;
The image processing method comprising:
6. The method of claim 5,
Encoding the average value slice to generate a bitstream;
The image processing method comprising the steps of:
6. The method of claim 5,
Encoding a plurality of slices comprising the average value slice and the difference values in parallel using a plurality of image encoding processors; And
Combining the encoded data to generate a bitstream
The image processing method comprising the steps of:
8. The method of claim 7,
And the encoding step records information on positions in subblocks of pixels constituting each slice in a slice header
Image Processing Method Using Image Segmentation.
The image frame is divided into a plurality of sub-blocks having a predetermined pixel size, and pixels corresponding to the same position corresponding to the same position in each sub-block of the plurality of sub-blocks are sampled to construct a plurality of macro blocks A video divider for dividing the plurality of macroblocks into a plurality of slices based on positions of the sampled pixels in subblocks;
A multiprocessor including a plurality of image encoding processors for encoding the plurality of slices in parallel; And
A data combining unit for combining the encoded data to generate a bitstream;
The image processing apparatus comprising:
10. The method of claim 9,
Wherein the image dividing unit further calculates an average value of the pixels of each of the plurality of subblocks and further configures one average value slice as the pixels having the average value
Image processing apparatus using image segmentation.
11. The method of claim 10,
Wherein the image dividing unit calculates the difference value between the pixels included in each of the plurality of slices and the pixels included in the average value slice and configures the plurality of slices as the difference values
Image processing apparatus using image segmentation.
12. The method of claim 11,
Wherein the plurality of image encoding processors encode the average value slice and a plurality of slices composed of the difference values in parallel
Image processing apparatus using image segmentation.
10. The method of claim 9,
Wherein the plurality of image encoding processors record information on positions in subblocks of pixels constituting each slice in a slice header during encoding
Image processing apparatus using image segmentation.
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