WO2005076627A1

WO2005076627A1 - Process method for compressing moving pictures and apparatus for performing said method

Info

Publication number: WO2005076627A1
Application number: PCT/KR2005/000373
Authority: WO
Inventors: Bong Jong Kim
Original assignee: Nevil Soft Co., Ltd.
Priority date: 2004-02-09
Filing date: 2005-02-07
Publication date: 2005-08-18

Abstract

A process method for moving pictures and apparatus for performing said method wherein an original image of the current frame is reduced and the reduced original image is established as a reference image, and a plurality of sub-images are generated from a frame having no time difference from the reference image and images of previous and next frames having very little time difference, and data of horizontal and vertical resolutions of the respective sub-images are alternatively erased in a predetermined order to take a differentiated portion between the reference image and the sub-images for compression, such that there is no time difference between the reference image and the sub-images to heighten the correlation and to remarkably improve data compression rate, and visual characteristics of the compressed images are enhanced to minimize the picture quality loss. Therefore, the picture quality can be remarkably improved even at the same compression rate.

Description

PROCESS METHOD FOR COMPRESSING MOVING PICTURES AND APPARATUS FOR PERFORMING SAID METHOD

FIELD OF THE INVENTION

The present invention relates to a process method for compressing moving pictures and

an apparatus for performing said method and, more particularly, to process methods for

compressing moving pictures and apparatus for performing said methods configured to

markedly improve picture quality even at the same compression rate.

BACKGROUND OF THE INVENTION

A conventional method of compressing moving pictures is to convert spatial

frequencies to time frequencies via a block segmentation method.

However, there is a drawback in the conventional method for compressing the moving

pictures thus described in that the number of calculations required for conversion via a

block segmentation method can be decreased. Further, block noise generated by the conventional block segmentation method such as a mosaic-like picture can be generated by the discontinuity of data at a borderline to deteriorate the picture quality such that the compression rate cannot be increased beyond a certain level.

SUMMARY OF THE INVENTION

The present invention is disclosed to solve the aforementioned drawbacks and it is an

object of the present invention to provide a process method for compressing moving

pictures and an apparatus for performing said method configured to markedly improve

the picture quality at the same compression rate.

In accordance with one embodiment of the present invention, there is provided' a

process method for compressing moving pictures wherein original images are

compressed via encoding and are outputted, the method comprising the steps of:

reducing an original image by a predetermined fraction to conform to an output

resolution and establishing the reduced original image as a reference image, and

copying the reference image in plural numbers for establishment as sub-images

(setting step); erasing pixels per predetermined order from horizontal and vertical

resolutions of each sub-image while alternating the pixel-erasing order at each sub-

image to thereby allow the pixels erased per sub-image to be alternated (alternating

step); allowing the reference image and the alternated sub-images to be arranged in

multi-frames along a time axis (arranging step); differentiating the respective sub- images from the reference image (differentiating step); deleting, from each

differentiated sub-image, areas of vertical and horizontal resolutions whose pixels are

erased in the alternating step and coupling the remaining non-deleted areas to thereby

reduce the overall resolutions of each sub-image (reducing step); and arranging the

reference image and the reduced sub-images on a two-dimensional space and

synthesizing the same into an image of a single frame, and compressing and outputting

the synthesized image (compressing and outputting step).

In accordance with another embodiment of the present invention, there is provided a

process method for decoding a compressed image and outputting the same, wherein a

reference image and a plurality of sub-images each having a value differentiated from

the reference image and a resolution lower than that of the reference image are

synthesized to be compressed into the compressed image of a single frame, the method

comprising the steps of: separating the reference image and respective sub-images

from the compressed image for arrangement on a time axis (arranging step);

expansively interpolating the respective separated sub-images to the same resolution as

that of the reference image (expansively interpolating step); adding the value differentiated from the reference image to each expanded sub-image (adding step); and insertedly coupling the pixels of the horizontal and vertical resolutions of each sub- image to which the differentiated values are added and the reference image onto a single frame according to a set order, and outputting by synthesizing the same into an

image of original resolution (synthesizing and outputting step).

In still another embodiment of the present invention, there is provided a process

method for compressing moving pictures wherein original images are compressed and

outputted by encoding, the method comprising the steps of: reducing an original

image by a predetermined fraction to conform to an output resolution and setting same

as a reference image, and copying the reference image in plural numbers and setting

same as sub-images (setting step); erasing pixels from horizontal and vertical

resolutions of each sub-image per set order wherein the pixel erasing order is

alternated for each sub-image such that a pixel erased for each sub-image can be

alternated (alternating step); arranging the reference image and the alternated sub-

images along a time axis in multiple frames (arranging step); differentiating the

respective sub-images from the reference image (differentiating step); deleting, from

each sub-image, areas of vertical and horizontal resolutions whose pixels are erased in

the alternating step and coupling the remaining non-deleted areas to thereby reduce the overall resolutions of each sub-image (reducing step); and arranging the reference image and the reduced sub-images in multiple frames along a time axis and compressing and outputting the same (arranging and compressing step). In accordance with still a further embodiment of the present invention, there is

provided a process method for decoding compressed images and outputting the same,

wherein a reference image and a plurality of sub-images each having a value

differentiated from the reference image and a resolution lower than that of the

reference image are compressed into respective frames and the compressed respective

frames are arranged along a time axis, the method comprising the steps of: separating

the reference image and the respective sub-images from the compressed images

(separating step); extensively interpolating the respective separated sub-images to the

same resolution as that of the reference image (extensively interpolating step); adding

the value differentiated from the reference image to each expanded sub-image (adding

step); and alternatively coupling the pixels of the horizontal and vertical resolutions of

each sub-image to which the differentiated values are added and the reference image

onto a single frame according to a set order and outputting by synthesizing the same in

an image of original resolution (synthesizing and outputting step).

In accordance with still a further embodiment of the present invention, there is provided a process method for compressing moving pictures wherein an original image is encoded, compressed and outputted, the method comprising the steps of: reducing an original image of a current frame by a predetermined fraction to conform to an output resolution and setting same as a reference image, and copying the reference image in plural numbers and setting same as sub-images (setting step); reducing

original images of a previous frame and a next frame by a predetermined fraction and

copying same in plural numbers and setting same as sub-images (setting step);

erasing pixels from horizontal and vertical resolutions of each sub-image at a

predetermined order wherein the order of erasing the pixels are alternated at every sub-

image such that pixels are alternated in being erased at each sub-image (alternating

step); arranging the reference image and the alternated sub-images in multiple frames

along a time axis (arranging step); differentiating the respective sub-images from the

reference image (differentiating step); and arranging the reference image and the

respective differentiated sub-images in multiple frames along the time axis, and

compressing and outputting same (compressing and outputting step).

In accordance with still further embodiment of the present invention, there is provided a process method for decoding compressed images and outputting the same, wherein a

reference image and a plurality of sub-images each having a differentiated value from the reference image and a resolution lower than that of the reference image are compressed into respective frames and the compressed respective frames are arranged along a time axis, the method comprising the steps of: separating the reference image and the respective sub-images from the compressed image (separating step); adding the value differentiated from the reference image to each said separated sub-image (adding step); and alternatively coupling the pixels of horizontal and vertical

resolutions of each sub-image to which the differentiated values are added and the

reference image onto a single frame according to a predetermined order and

compressing and outputting same as an image of original resolution (compressing and

outputting step).

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of the present invention, reference

should be made to the following detailed description with the accompanying drawings,

in which:

FIG. 1 is a schematic block diagram for illustrating encoding means out of apparatuses for performing a process method for compressing moving pictures according to a first embodiment of the present invention;

FIG. 2 is a schematic block diagram for illustrating decoding means out of apparatuses for performing the process method for compressing the moving pictures according to the first embodiment of the present invention; FIG. 3 is a schematic drawing for explaining a step for dividing an original image into

a reference image and a plurality of sub-images for encoding;

FIG. 4 is a schematic drawing for explaining a step of alternatively separating pixels

from each sub-image and erasing same;

FIGS. 5 and 6 are schematic drawings for explaining a step of comparing each sub-

image with a reference image for differentiation;

FIG. 7 is a schematic drawing for explaining a step of erasing a pixel of level having a

difference within a predetermined scope in the respective differentiated sub-images;

FIG. 8 is a schematic drawing for explaining a step of arranging and synthesizing a reference image and each sub-image in a single frame;

FIG. 9 is a schematic drawing for explaining a step of separating a synthesized image into a reference image and each sub-image for decoding;

FIG. 10 is a schematic drawing for explaining a step of expanding a resolution of each sub-image to that of a reference image; FIG. 11 is a schematic drawing for explaining a step of interpolating pixels relative to a

sub-image of a current frame using frames before and after the current frame;

FIG. 12 is a schematic drawing for explaining a step of composing an image of an

original resolution using a reference image and sub-images;

FIG. 13 is a schematic block drawing of encoding means out of apparatuses for

performing a process method for compressing moving pictures according to a second

embodiment of the present invention;

FIG. 14 is a schematic block drawing of decoding means out of apparatuses for

performing a process method for compressing moving pictures according to the second

embodiment of the present invention;

FIG. 15 is a schematic drawing for explaining a step of dividing an original image into a reference image and a plurality of sub-images for encoding;

FIG. 16 is a schematic drawing for explaining a step of pairing up sub-images and synthesizing the paired sub-images along a time axis; FIG. 17 is a schematic drawing for explaining a step of arranging and synthesizing a

reference image and sub-images along a time axis;

FIG. 18 is a schematic drawing for explaining a step of separating a synthesized image

into a reference image and respective sub-images for decoding;

FIG. 19 is a schematic block drawing of encoding means out of apparatuses for

performing a process method for compressing moving pictures according to a third

embodiment of the present invention;

FIG. 20 is a schematic block drawing of decoding means out of apparatuses for

performing a process method for compressing moving pictures according to a

preferred embodiment of the present invention;

FIG. 21 is a schematic drawing for explaining a step of dividing an original image into a reference image and a plurality of sub-images for encoding;

FIG. 22 is a schematic drawing for explaining a step of pairing up sub-images and synthesizing the paired-up sub-images along a time axis; FIG. 23 is a schematic drawing for explaining a step of arranging and synthesizing a

reference image and sub-images along a time axis;

FIG. 24 is a schematic drawing for explaining a step of adding a differentiated value to

a sub-image for restoration; and

FIG. 25 is a schematic drawing for explaining a step of using a reference image and

sub-images to synthesize an image having an original resolution.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment of the present invention will now be described in detail

with reference to the annexed drawings, where the present embodiment is not limiting

the scope of the present invention but is given only as an illustrative purpose.

The present invention is configured to markedly improve a picture quality by allocating a data of a scale addition information being added and coded to a sub channel of an original image while having the same compression rate as that of the known compression technique. [FIRST EMBODIMENT]

An apparatus for performing a first embodiment of the present invention includes

encoding means and decoding means. The encoding means includes an image space

separator (10), an image frame generator (20), a reference image resolution sheer (30),

a sub-image subtracter (40), a sub-image level detector (50), a sub-image slicer (60), a

sub-image resolution slicer (70) and an image synthesizer (80), as shown in FIG.1.

The image space separator (10) performs a processing work (hereinafter referred to as

alternative erasion) where an original image is reduced by a predetermined fraction to

conform to an output resolution whereby the reduced image is established as a

reference image, and the reference image is plurally copied and the plurally-copied

images are established as sub-images, wherein pixels are erased from horizontal and

vertical resolutions of each sub-image according to a predetermined order while the

pixel erasing order is alternated for each sub-image such that the pixels being erased at

each sub-image can be alternated.

The image frame generator (20) arranges the reference image and the sub-images

processed at the image space separator (10) along a time axis, and the reference image resolution slicer (30) separates the reference image from the sub-images for

transmission to the image synthesizer (80).

The sub-image subtracter (40) differentiates each sub-image from the reference image,

while the sub-image level detector (50) detects a pixel value of each differentiated sub-

image.

The sub-image slicer (60) compares pixel values of each differentiated sub-images to

erase pixel values each having a difference within a predetermined scope, and again

compares a pixel value of each sub-image with that of the reference image to erase a

pixel value having a difference within a predetermined scope.

The sub-image resolution slicer (70) deletes, for each sub-image, areas of the vertical and horizontal resolutions whose pixels were erased in the alternative erasion step and couples the remaining non-deleted areas to thereby reduce the overall resolutions of each sub-image.

The image synthesizer (80) arranges the reference image and the reduced sub-images on a two-dimensional space, and synthesizes and compresses same to an image of a single frame to be outputted. Referring to FIG. 2, the decoding means for performing the first embodiment of the

present invention includes an inverse image separator (110), a reference image

resolution expander (120), a sub-image resolution expander (130), a three-dimensional

frame comparator (140), a three-dimensional frame adder (150), a three-dimensional

frame synthesizer (160) and an image synthesizer (170).

The inverse image separator (110) separates the reference image and the sub-images

from the compressed images outputted from the image synthesizer (80) of the afore-

mentioned encoding means and arranges same on a time axis.

The reference image resolution expander (120) transmits to the image synthesizer

(170) the reference image separated from the inverse image separator (110). The

sub-image resolution expander (130) expands the resolution of each sub-image

separated from the inverse image separator (110) to the same resolution of the

reference image for interpolation.

The three-dimensional frame comparator (140) compares the expansively interpolated sub-images with the reference image to detect the same and different pixels between the sub-images and the reference image and detect pixels each having a difference therebetween, i.e., detect a differentiated status.

The three-dimensional frame adder (150) adds to each sub-image a value differentiated

from the reference image in response to the differentiated status detected by the three-

dimensional frame comparator (140), and the three-dimensional frame synthesizer

(160) buffers each sub-image added by the differentiated value for image synthesis of

the original resolution.

The image synthesizer (170) alternatively and insertedly couples the pixels of vertical

and horizontal resolutions of the reference image and the sub-images on a single frame

in response to a predetermined order to synthesize and output an image of original

resolution.

The operational example of the first embodiment of the present invention thus constructed will now be described in detail with reference to the accompanying drawings.

First, an encoding process will be described.

A resolution of an original image (lo, i.e., an image of a currently- worked frame out of moving pictures comprising a plurality of frames) is comprised of a two-dimensional

plane of M*N having a horizontal direction (x) and a vertical direction (y), as shown in

FIG. 3. The original image thus described is reduced and copied in plural numbers in

accordance with an M/m*N/n image which is an image to be finally outputted via the

image space separator (10). The reduced original image is set as a reference image (Ir)

while the copied plural images are set as sub-images (Is).

The sub-images (Is) are erased of their pixels of horizontal and vertical resolutions

according to a predetermined order based on the reference image (Ir) via the image

space separator (10) as shown in FIG. 4, wherein the pixel erasing order is alternated

for each sub-image such that pixels erased at each sub-image are alternatively

processed.

For example, a first sub-image (Is) erases the even-numbered pixels at the horizontal

resolution and the even- numbered pixels at the vertical resolution, and then, the next sub-image (Is) erases the odd-numbered pixels at the horizontal resolution and the even-numbered pixels at the vertical resolution, and then, the following sub-image (Is) erases the even-numbered pixels at the horizontal resolution and the odd-numbered pixels at the vertical resolution, and then, the next following sub-image (Is) erases odd- numbered pixels at the horizontal resolution and the odd-numbered pixels at the vertical resolution.

The reference image (Ir) and the sub-images (Is) thus processed are arranged in plural

frames along the time axis by the image frame generator (20). In other words, the

frame of the reference image (Ir) is added by the frames of the plurality of sub-images

(Is) to thereby exceed the number of the original frame of the moving pictures (for

example, approximately 29.97 frames per second under NTSC broadcasting

regulation).

Referring now to FIGS. 5 and 6, the sub-images (Is) are differentiated from the

reference image (Ir) via the sub-image subtracter (40) to thereby remove the spatial

correlation on the two-dimensional plane having the M*N frequency via the differentiation thus described.

The correlation between the reference image (Ir) and the sub-images (Is) thus differentiated is greater than that between two timely neighboring frames (original image frames). This is because components having time lag do not exist between the reference image (Ir) and the sub-images (Is) but there is only a frequency difference within the same space in the present invention, while time lag between moving components exists in the case of an image taking up a differentiation between neighboring frames via a general compression method.

Therefore, an image data of sub-images taking up the differentiation according to the

present invention can have a higher correlation to thereby enable to heighten a

compression rate while maintaining the same picture quality than that of a case of an

image taking up a differentiation between images of neighboring frames according to

the general compression method.

For example, even the resolution of the sub-image (Is) is more compressed by

approximately a quarter or above than that of the reference image (Ir) by the sub-image

resolution slicer (70), an image of less picture quality deterioration can be embodied

compared with the general compression method.

Next, each pixel value of respective differentiated sub-images (Is) is detected by the sub-image level detector (50), and the sub-image slicer (60) performs a first slicing process where a zero pixel value is reallocated to any pixel of the sub-image (Is) whose pixel value lies between a predetermined upper and lower limit based on a zero pixel value. In other words, although the differentiated pixel having a pixel value between the upper and lower limits appropriately predetermined according to the brightness or darkness of the relevant image sections is sliced, a human's eye is unable to easily discern a difference before and after the slicing).

Particularly, because a human cannot distinguish the difference between an original

image and a sliced image in a very small value, there would be no problem if all image

data within approximately 8 pixel values out of plus (+) and minus (-) components in

the differentiated values are treated identically as the reference image data.

Consequently, values lying between the upper and lower limit out of pixel values of the

sliced sub-images (Is) can be substituted by zero values because a human's eye cannot

distinguish the difference. The slicer (60) performs a second slicing process for the

firstly sliced sub-images (Is) thus explained above where the firstly sliced sub-images

(Is) are compared with the reference image (Ir) in terms of pixel values, and the pixel

values of the firstly sliced sub-images (Is) within the scope of the predetermined upper

and lower limits based on the relevant pixel values of the reference image (Ir) are substituted by zero values. Most of the pixels of each sub-image (Is) now come to have zero pixel values after the second slicing process as shown in FIG. 7.

Data of the sub-images (Is) thus reconstructed through the first and second slicing processes may be deleted because it does not matter even if the pixels of such sliced sub-images (Is) having zero pixel values are substituted by those of the reference image (Ir) during decoding.

In this case, the horizontal and vertical resolutions of sub-images (Is) other than the

reference image (Ir) can be reduced by approximately 1/2 or above. This is because the

scope of data size reducible without any loss to an original image signal is

approximately 1/2 when differentiation is made from neighboring frames. Data

approximately half the size has large overlapped portions with neighboring frames.

Meanwhile, it is preferred that an extra weight be added to the upper and lower limit

values of the horizontal resolution instead of those of the vertical resolution during the

first and second slicing processes. This is because the horizontal resolution responds

more sensitively than the vertical resolution to a human's eyes. It is also preferred that

the data of horizontal resolution be given with such upper and lower limit values that slicing width can be smaller than that of the vertical resolution to thereby increase the accuracy of the data.

Meanwhile, it is also preferred that the pixel values of the vertical resolution be placed further near to zero by widening the slicing scope, and in this case, the sub-images (Is) having data of vertical resolution have a relatively inferior fidelity such that sub- images (Is) having mostly data of vertical resolution are removed. Furthermore, sub-images (Is) having data of horizontal resolution are also removed of

lots of data during differentiation with the reference image (Ir), which means that

spatial and timely overlap in a screen is effectively removed as much as the removed

sub-images (Is) of the horizontal resolution.

Consequently, the present invention can further increase the compression efficiency

compared with that of the conventional block compression techniques because

frequency correlation of the overall images is effectively erased, resulting in a

remarkable improvement from the decreased picture quality.

Next, each sliced sub-image (Is) is reduced in overall resolution thereof because areas

of vertical and horizontal resolutions previously removed of pixels at the image space

separator (10) step are deleted and coupled by the sub-image resolution slicer (70), and

the resolution at this time is preferred to be reduced to a size of even fraction (not odd

fraction), for example, approximately 1/4 of the reference image (Ir).

Referring now to FIG. 8, the reference image (Ir) and the reduced sub-images (Is) are arranged on a two-dimensional space by the image synthesizer (80) to perform a time compression of being synthesized of a single frame. For example, the reference image (Ir) is allocated to a left or a right side of the image while sub-images (Is) are allocated

to a remaining space of the reference image (Ir).

The sub-images (Is) synthesized along with the reference image (Ir) have been already

removed of lots of data having large overlap via differentiation with the reference

image (Ir), and compressed by the image synthesizer (80) via known Run Length

Coding (RLC) method or the like for storage and outputting.

In other words, an image composed of images synthesized with the reference image

(Ir) reduced to as much as a predetermined fraction of the original image (lo), the sub-

images (Is) and an image having a differentiated data between the sub-image (Is) and

the reference image (Ir) is finally compressed and outputted.

As mentioned, although the finally-outputted compressed image is reduced by as much

as the predetermined fraction compared with the original image (lo), the control of the compression rate depends on the accuracy of time-compressed sub-image (Is), i.e., how much data of a sub-image having small loss rate of picture quality out of the sub- images (Is) is reduced or removed. In this case, the loss of data occurs in accordance with the order of less importance with regard to the fidelity of the original image. However, deterioration of picture quality of an image is not that severe compared with that of the existing compression technique.

Next, the decoding process will be explained.

Referring to FIG. 9, the compressed image outputted via the image synthesizer (80) of

the encoding means is divided into a reference image (Ir) and sub-images (Is) by the

inverse image separator (110) and arranged along the time axis. Each sub-image (Is)

separated from the inverse image separator (110) is expanded to the same resolution as

that of the reference image (Ir) by the sub-image resolution expander (130) (see FIG.

10). The resolution expansion of the sub-images (Is) is conducted by a pixel

interpolation method for increasing the number of pixels by copying neighboring

pixels. Most of the sub-images (Is) having the horizontal resolution are restored to

original images, but some of the sub-images having vertical resolution include frames

that are not restored.

As exemplified in FIG. 11, the sub-image resolution expander (130) applies to a lost pixel (op) of the sub-image (Is), an average (A) of a pixel value (f) of a frame thereof, a pixel value (f-1) relative to the same position of a previous frame of the current frame and a pixel value (f+1) relative to the same position of a next frame of the current frame to restore the loss. However, if the average (A) is smaller than f/2, (f- 1 )/2 or (f+l)/2, "f is compared with "f-1" and "f+1", and the smallest of the three is

substituted into the pixel (op).

Each sub-image (Is) expanded by the sub-image resolution expander (130) is

compared with the reference image (Ir) via the three-dimensional comparator (140) to

detect a differentiated status, i.e., the same and different pixels between the sub-images

and the reference image.

from the reference image (Ir) in response to the differentiated status detected by the

three-dimensional frame comparator (140) to restore the image data of each sub-image,

and the restored sub-images (Is) are buffered by the three-dimensional frame

synthesizer (160) for image synthesis on a two-dimensional plane.

Referring now to FIG. 12, the respective sub-images (Is) inputted to the image synthesizer (170) after buffering at the three-dimensional frame synthesizer (160) are synthesized along with the reference image (Ir) into an image of original resolution at the image synthesizer (170) by alternatively and insertedly coupling the pixels of horizontal and vertical resolutions in accordance with a predetermined order onto a single frame of a two-dimensional plane, and then outputted. There is an advantage in the first embodiment of the present invention thus explained

in that a space of an original image is reduced to a predetermined fraction for an

establishment of a reference image, and a plurality of sub-images having timely

continuity are copied from the reference image and are allocated, and in order to

remove the correlation within a space, differentiations are mutually performed and data

imperceptible to a human's visual characteristic is removed to compress data of overall

images, such that deterioration of picture quality resulting from a data discontinuity at

a borderline generated from the conventional block compression method can be

markedly attenuated to bring about an improvement of visual characteristics. In other

words, the visual characteristic is improved to allow the data to be compressed as

much such that picture quality can be further improved at the same compression rate.

[SECOND EMBODIMENT]

An apparatus for implementing a second embodiment of the present invention includes encoding means and decoding means.

As illustrated in FIG. 13, the encoding means further includes an image space separator (210), an image frame generator (220), a reference image resolution slicer (230), a sub- image subtracter (240), a sub-image level detector (250), a sub-image slicer (260), a

sub image time compressor (270), a sub-image space converter (280) and an image

synthesizer (290).

The image space separator (210) performs a processing work (hereinafter referred to as

conform to an output resolution whereby the reduced image is established as a

each sub-image can be alternated..

The image frame generator (220) arranges the reference image and the sub-images

processed at the image space separator (210) along a time axis, and the reference image resolution slicer (230) separates the reference image from the sub-images for transmission to the image synthesizer (290)

The sub-image subtracter (240) differentiates each sub-image from the reference image, while the sub-image level detector (250) detects a pixel value of each differentiated sub-image.

The sub-image slicer (260) compares pixel values of each differentiated sub-images to

erase pixel values each having a difference within a predetermined scope, and again compares a pixel value of each sub-image with that of the reference image to erase a pixel value having a difference within a predetermined scope.

The sub-image time compressor (270) pairs off with neighboring frames relative to each sub-image to time-compress and synthesizes the paired-off frames. The sub image

^• space converter (280) deletes, for each sub-image, areas of the vertical and horizontal resolutions whose pixels were erased in the alternative erasion and couples the remaining non-deleted areas to thereby reduce the overall resolutions of each sub- image.

The image synthesizer (290) arranges the reference image and the reduced sub-images on a three-dimensional space along a time axis, and compresses the same for output.

Next, the decoding means for conducting the second embodiment of the present invention includes, as shown in FIG. 14, an inverse image separator (310), a reference image resolution expander (320), a sub-image space converter (330), a sub-image frame detector (340), a three-dimensional frame synthesizer (350), a sub-image adder

(360), a three-dimensional image generator (370) and an image synthesizer (380).

The inverse image separator (310) separates the reference image and the sub-images

from the compressed images outputted from the image synthesizer (290) of the afore¬

mentioned encoding means and arranges same on a time axis.

The reference image resolution expander (320) transmits to the three-dimensional

image generator (370) the reference image separated from the inverse image separator

(310). The sub-image resolution expander (330) expands the resolution bf each sub-

image separated from the inverse image separator (310) to the same resolution of the

reference image for interpolation.

The three-dimensional frame comparator (350) detects a level of pixel value of each

expansively interpolated sub-image and compares the pixels of the sub-images with

the reference image, and detects a differentiated status, that is, different pixels between the sub-images and the reference image.

The three-dimensional frame synthesizer (350) compares the correlation of pixels between the current frame and each of neighboring previous and next frames per horizontal and vertical resolutions for omitted data of each sub-images discovered by

the result detected by the sub-image frame detector (340), and takes a pixel of a higher

correlation for correction.

The sub-image frame adder (360) adds to each sub-image a value differentiated from

the reference image in response to the differentiated status detected by the sub-image

frame detector (340), and the three-dimensional image generator (370) performs a

buffering process for the reference image and each sub-image for image synthesis.

The image synthesizer (380) alternatively and insertedly couples the pixels of vertical

and horizontal resolutions of the reference image and the sub-images on a single frame in response to a predetermined order to synthesize and output an image of original resolution.

The operational example of the second embodiment of the present invention thus constructed will now be described in detail with reference to the accompanying drawings.

First, an encoding process will be described. A resolution of an original image (lo, i.e., an image of a currently-worked frame out of

moving pictures comprising a plurality of frames) is comprised of a two-dimensional

FIG. 15. The original image thus described is reduced and copied in plural numbers in

accordance with an M/m*N/n image which is an image of a final output end via the

image space separator (210). The reduced original image is set as a reference image

(Ir) while the copied plural images are set as sub-images (Is).

space separator (210), wherein the pixel erasing order is alternated for each sub-image

such that pixels erased at each sub-image are alternatively processed.

resolution and the even-numbered pixels at the vertical resolution, and then, the next sub-image (Is) erases the odd-numbered pixels at the horizontal resolution and the even-numbered pixels at the vertical resolution, and then, the following sub-image (Is) erases the even-numbered pixels at the horizontal resolution and the odd-numbered pixels at the vertical resolution, and then, the next following sub-image (Is) erases the odd-numbered pixels at the horizontal resolution and the odd-numbered pixels at the vertical resolution.

frames along the time axis by the image frame generator (220). In other words, the

example, approximately 29.97 frames per second under NTSC broadcasting

regulation).

The sub-images (Is) thus described are differentiated from the reference image (Ir) via

the sub-image subtracter (240) to thereby remove the spatial correlation on the two-

dimensional plane having the M*N frequency via the differentiation thus described

(see FIGS. 5 and 6 of the first embodiment).

The correlation between the reference image (Ir) and the sub-images (Is) thus differentiated is greater than that between two timely neighboring frames (original image frames). This is because components having time lag do not exist) between the reference image (Ir) and the sub-images (Is) but there is only a frequency difference within the same space in the present invention, while time lag between moving components exists in a case of an image taking up a differentiation between neighboring frames via a general compression method.

present invention can have a higher correlation to thereby enable to heighten a

compression rate while maintaining the same picture quality as an image taking up a

differentiation between images of neighboring frames according to the general

compression method.

For example, even the resolution of the sub-image (Is) is more compressed by

space converter (280), an image of less picture quality deterioration can be embodied

compared with the general compression method.

Next, each pixel value of respective differentiated sub-images (Is) is detected by the

sub-image level detector (250), and the sub-image slicer (260) performs a first slicing

process where a zero pixel value is reallocated to any pixel of the sub-image (Is)

whose pixel value lies between a predetermined upper and lower limit based on a zero

pixel value). In other words, although the differentiated pixel having a pixel value

between the upper and lower limits appropriately predetermined according to the

brightness or darkness of the relevant image sections is sliced, a human's eye is unable to easily discern a difference before and after the slicing.

the differentiated values are treated identically as the reference image.

sliced sub-images (Is) can be substituted to zero values because a human's eye cannot

and lower limits based on the relevant pixel values of the reference image (Ir) are

substituted by zero values. Most of the pixels of each sub-image (Is) now come to have

zero pixel values after the second slicing process (see FIG. 7 of the first embodiment)

scope of data size reducible without any loss to an original image signal is

approximately 1/2 when differentiation is made from neighboring frames. Data

the data of horizontal resolution be given with such upper and lower limit values that

slicing width can be smaller than that of the vertical resolution to thereby increase the

accuracy of the data.

spatial and timely overlap in a screen is effectively removed as much as possible.

compared with the conventional block compression techniques because frequency

correlation of the overall images is effectively erased, resulting in a remarkable

improvement from the decreased picture quality.

Referring now to FIG. 16, the respective sliced sub-images pair off with timely

neighboring frames via the sub-image time compressor (270) and an average (A) is

calculated from pixel values of paired-off sub-images (Is) and is substituted into the

synthesized pixel values to generate a new synthesized sub-image (Is).

If the average (A) is less than a half value of the pixel value (f) of the current frame,

less than a half value of the pixel value (f-1) relative to the same position of the previous frame or less than a half value of the pixel value (f+1) relative to the same position of the next frame, a representative value extraction technique is applied for correction where "f ', "f-1" and "f+1" are compared thereamong and the smallest value thereof is substituted into the synthesized pixel value (see FIG. 11 of the first

embodiment). At this time, if the neighboring plural sub-images are synthesized into a

single frame, there is a fear of generating a negative (-) component, such that an

appropriate value is added to remove the negative (-) component (for example, adding

a value of approximately 64).

The reason for synthesizing the sub-images along the time axis is to satisfy a number

of frames when the number of sub-images (Is) exceeds the number of frames of

outputted images in cases where the number of frames of images outputted via

encoding is fixed. In other words, the number of sub-images (Is) is increased more

than the number of frames of images outputted at the step of the image space separator

(210) to increase the accuracy of images, and the number of frames is decreased by the

time compression to meet the number of frames of outputted images.

Next, each time-compressed sub-image (Is) is reduced in overall resolution thereof

because areas of vertical and horizontal resolutions previously removed of pixels at the image space separator (210) step are deleted and coupled by the sub-image space converter (280), and the resolution at this time is preferred to be reduced to a size of even fraction (not odd fraction), for example, approximately 1/4 of the reference image (Ir). Referring now to FIG. 17, the reference image (Ir) and the reduced sub-images (Is) are

arranged on a three-dimensional space along a time axis by the image synthesizer

(290).

image (Ir), and compressed by the image synthesizer (80) via known Run Length

Coding (RLC) method or the like for storage and outputting.

the reference image (Ir) is finally compressed and outputted.

as the predetermined fraction compared with the original image (lo), the control of the

compression rate depends on the accuracy of time-compressed sub-image (Is), i.e.,

how much data of a sub-image having small loss rate of picture quality out of the sub- images (Is) is reduced or removed. In this case, more data is lost in an image having less importance. However, deterioration of picture quality of an image is not that

severe compared with that of the existing compression technique.

Next, the decoding process will be explained.

Referring to FIG. 18, the compressed image outputted via the image synthesizer (290)

of the encoding means is divided into a reference image (Ir) and sub-images (Is) by the

inverse image separator (310) and arranged along the time axis. Each sub-image (Is)

separated from the inverse image separator (310) is expanded to the same resolution as

that of the reference image (Ir) by the sub-image space converter (330) (see FIG. 10 of

the first embodiment). The resolution expansion of the sub-images (Is) is conducted by

a pixel interpolation method for increasing the number of pixels by copying

neighboring pixels.

Each sub-images (Is) expanded by the sub-image space converter (330) is detected of levels of each pixel value via the sub-image frame detector (340) for comparison with the reference image (Ir), from which a pixel having a difference from the same pixel between the sub-images and the reference image is detected, that is, a differentiated status is detected. When pixel values of each sub-image are detected by the sub-image space converter (330), there may be data that are not restored. In order to restore the data, the three-dimensional frame synthesizer (350) compares

correlation of pixels between the current frame and each of neighboring previous and

next frames per horizontal and vertical resolutions for omitted data of each sub-images,

and takes a pixel of a higher correlation for restoration.

In other words, the current frame is compared with timely neighboring previous and

next frames, and a determination is made as to which of the relevant portions of the

neighboring frames has a higher correlation with pixels of vertical or horizontal

resolution omitted from the current frame, and the determination therefrom uses

information provided from the differentiated erasion process conducted by the image

space separator (210) during encoding and resolution reducing process by the sub-

image space converter (280).

For example, if the reduction of resolution of sub-images (Is) of a current frame has been affected by deletion of even pixels of horizontal resolution and odd pixels of vertical resolution during encoding, the former may be restored by taking the even pixels of horizontal resolution from the previous frame, and the latter may be restored by taking the odd pixels of vertical resolution from the next frame. Each sub-image (Is) is added by a differentiated value from the reference image (Ir) by

the sub-image adder (360) in response to the differentiated status detected by the sub-

image frame detector (340) to restore the image data of each sub-image (Is), and the

reference image (Ir) transmitted via the reference image resolution expander (320) and

the respective restored sub-images (Is) are buffered by the three-dimensional image

generator (370) for image synthesis on the two-dimensional plane.

The reference image (Ir) and each sub-image (Ir) buffered by the three-dimensional

image generator (370) and inputted to the image synthesizer (380) are synthesized into

an image of original resolution by alternatively and insertedly coupling the pixels of

horizontal and vertical resolutions in accordance with a predetermined order onto a

single frame of a two-dimensional plane, and then outputted (see FIG. 12 of the first

embodiment).

There is an advantage in the second embodiment of the present invention thus explained in that a space of an original image is reduced to a predetermined fraction for an establishment of a reference image, and a plurality of sub-images having timely continuity are copied from the reference image and are allocated, and in order to remove the correlation within a space, differentiations are mutually performed and data imperceptible due to a human's visual characteristic is removed to compress data of overall images, such that deterioration of picture quality resulting from data

discontinuity at a borderline generated from the conventional block compression

method can be markedly attenuated to bring about an improvement of a human's visual

characteristic. In other words, the visual characteristic is improved to allow the data to

be compressed as much as possible, so that picture quality can be further improved at

the same compression rate.

[THIRD EMBODIMENT]

An apparatus for implementing a third embodiment of the present invention includes

encoding means and decoding means. As shown in FIG.19, the encoding means

includes an image space separator (410), a reference image resolution slicer (420), a

three-dimensional image frame generator (430), a sub-image subtracter (440), a sub-

image time compressor (450) and a three-dimensional frame synthesizer (460).

The image space separator (410) performs a processing work (hereinafter referred to as alternative erasion) where an original image of the current frame is reduced by a predetermined fraction to conform to an output resolution whereby the reduced image is established as a reference image, and the reference image is plurally copied and the plurally-copied images are established as sub-images, wherein pixels are erased from horizontal and vertical resolutions of each sub-image according to a predetermined

order while the pixel erasing order is alternated for each sub-image so that the pixels

being erased at each sub-image can be alternated.

The reference image resolution slicer (420) separates the reference image from the

sub-images for transmission to the three-dimensional frame synthesizer (460). The

three-dimensional image frame generator (430) arranges the sub-images of a previous

frame, the current frame and a next frame processed by the image space separator

(410) on a time axis according to a time order.

The sub-image subtracter (440) differentiates the respective sub-images from the

reference image, and the sub-image time compressor (450) pairs off the neighboring

frames for the respective sub-images and time-compresses the same to be outputted.

The three-dimensional frame synthesizer (460) arranges the reference image and the

reduced sub-images on a three-dimensional space along a time axis for compression

and outputting.

Next, the decoding means for implementing the third embodiment of the present invention includes an inverse image separator (510), a reference image resolution expander (520), a three-dimensional image adder (530), a three-dimensional image comparator (540) and a three-dimensional frame synthesizer (550).

The inverse image separator (510) separates the reference image and the sub-images

from the compressed images outputted from the three-dimensional frame synthesizer

(460) of the afore-mentioned encoding means and arranges same on a time axis.

The reference image resolution expander (520) transmits to the three-dimensional

frame synthesizer (550) the reference image separated from the inverse image

separator (510). The three-dimensional image adder (530) detects the differentiated

status of each sub-image to add the differentiated value of the reference image to the

respective sub-images, and the three-dimensional image comparator (540) detects data

differentiated relative to the respective sub-images.

The three-dimensional frame synthesizer (550) alternatively and insertedly couples the

pixels of horizontal and vertical resolutions of the reference image and the sub-images according to a predetermined order onto a single frame in response to the differentiated data detected by the three-dimensional image comparator (540) for synthesis to an image of original resolution and outputting.

The operational example of the third embodiment of the present invention thus described will now be explained with reference to the accompanying drawings.

First, an encoding process will be described.

A resolution of an original image (lo, i.e., an image of a currently-worked frame out of

FIG. 21. The original image thus described is reduced and copied in plural numbers in

(Ir) while the copied plural images are set as sub-images (Is).

At the same time, the image space separator (410) reduces the original image of a

previous and a next frame from the current frame by a predetermined fraction and the

reduced original image is copied in plural numbers, which are established as respective sub-images. For reference, the number of sub-images of the previous and next frames is preferably half the number of the sub-images (Is) of the current frame.

The respective sub-images (Is) of the previous frame, the current frame and the next frame are erased of their pixels of horizontal and vertical resolutions according to a predetermined order based on the reference image (Ir) via the image space separator

(410), wherein the pixel erasing order is alternated for each sub-image so that pixels

erased at each sub-image are alternatively processed.

resolution and the even-numbered pixels at the vertical resolution, and then, the next

sub-image (Is) erases the odd-numbered pixels at the horizontal resolution and the

even-numbered pixels at the vertical resolution, and then, the following sub-image (Is)

erases the even-numbered pixels at the horizontal resolution and the odd-numbered

pixels at the vertical resolution, and then, the next following sub-image (Is) erases odd-

numbered pixels at the horizontal resolution and the odd-numbered pixels at the

vertical resolution.

The reason for generating the sub-images (Is) of previous and next frames in addition

to the current frame is to allow the sub-images (Is) of the previous and next frame

adjacent to the current frame to have lots of pixel information having a small

difference from the current frame during the differentiation from the reference image

(Ir) while there is almost no time lag from the current frame, thereby enabling to compensate the pixel loss during the decoding process for prevention of deterioration of picture quality. The reference image (Ir) and the sub-images (Is) thus processed are arranged in plural

frames along the time axis by the image frame generator (430). In other words, the

example, approximately 29.97 frames per second under NTSC broadcasting

regulation).

the sub-image subtracter (440) to thereby remove the spatial correlation on the two-

(see FIGS. 5 and 6 of the first embodiment).

Referring now to FIG. 22, the respectively differentiated sub-images pair off with timely neighboring frames via the sub-image time compressor (450) and an average (A) is calculated from pixel values of paired-off sub-images (Is) and is substituted into the synthesized pixel values to generate a new synthesized sub-image (Is).

If the average (A) is less than a half value of the pixel value (f) of the current frame, less than a half value of the pixel value (f-1) relative to the same position of the front frame or less than a half value of the pixel value (f+1) relative to the same position of

the rear frame, a representative value extraction technique is applied for correction

where "f, "f-1" and "f+1" are compared thereamong and a smallest value thereof is

substituted into the synthesized pixel value. At this time, if the neighboring plural sub-

images are synthesized into a single frame, there is a fear of generating a negative (-)

component, such that an appropriate value is added to remove the negative (-)

component (for example, adding a value of approximately 64).

of frames when the number of sub-images (Is) exceeds the number of frames of

outputted images in cases where the number of frames of images outputted via

than the number of frames of images outputted at the step of the image space separator (410) to increase the accuracy of images, and the number of frames is decreased by the time compression to meet the number of frames of outputted images.

Referring now to FIG. 22, the time-compressed sub-images (Is) are arranged on a three-dimensional space along with the reference image (Ir) on the time axis by the three-dimensional frame synthesizer (460). The sub-images (Is) arranged along with the reference image (Ir) have been already

image (Ir), such that the sub-images are compressed by the three-dimensional frame

synthesizer (460) via the known Run Length Coding (RLC) method or the like for

storage and outputting.

the reference image (Ir) is finally compressed and outputted.

compression rate depends on the accuracy of the time-compressed sub-image (Is), i.e.,

how much data of a sub-image having a small loss rate of picture quality out of the sub-images (Is) is reduced or removed. In this case, data loss occurs in accordance

with the order of importance with regard to the fidelity of the original image. However, deterioration of picture quality of an image is not that severe compared with that of the existing compression technique. Next, the decoding process will be explained.

The compressed image outputted via the three-dimensional frame synthesizer (460) of

inverse image separator (510) and arranged along the time axis. Each sub-image (Is)

separated from the inverse image separator (510) is added by a differentiated value

from the reference image (Ir) at the three-dimensional image adder (530) to restore the

image data of the respective sub-images (Is) (see FIG. 24).

For each sub-image (Is) whose differentiated value was restored, the data differentiated

during the encoding process are detected by the three-dimensional image comparator

(540), and pixels of horizontal and vertical resolutions of the reference image and the

sub-images are alternatively and insertedly coupled by the three-dimensional frame

synthesizer (550) in accordance with the differentiated data detected by the three- dimensional comparator (540) in response to a predetermined order onto the single frame and then synthesized into an image of original resolution to be outputted ( see FIG. 25).

There is an advantage in the third embodiment of the present invention thus explained in that a space of an original image is reduced to a predetermined fraction for an establishment of a reference image, and a plurality of sub-images having timely

remove the correlation within a space, differentiations are mutually performed and a

data imperceptible due to a human's visual characteristic is removed to compress data

of overall images, such that deterioration of picture quality resulting from a data

discontinuity at a borderline generated from the conventional block compression

be compressed as much as possible, such that picture quality can be further improved

at the same compression rate.

The foregoing description of the preferred embodiment of the present invention has

been presented for the purpose of illustration and description. It is not intended to be

exhaustive or to limit the invention to the precise form disclosed, and modifications

and variations are possible in light of the above teachings or may be acquired from practice of the invention. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A process method for compressing moving pictures, wherein original images

are compressed via encoding and are outputted, comprising the steps of: reducing an original image to a predetermined fraction to conform to an output

copying the reference image in plural numbers to be set as sub-images (setting step); erasing pixels per predetermined order from horizontal and vertical resolutions

of each sub-image while alternating the pixel-erasing order at each sub-image to

thereby allow the pixels erased per sub-image to be alternated (alternating step); allowing the reference image and the alternated sub-images to be arranged in

multi-frames along a time axis (arranging step); differentiating the respective sub-images from the reference image

(differentiating step); deleting, from each differentiated sub-image, areas of vertical and horizontal resolutions whose pixels are erased in the alternating step and coupling the remaining non-deleted areas to thereby reduce the overall resolutions of each sub-image (reducing step); and arranging the reference image and the reduced sub-images on a two- dimensional space and synthesizing the same into an image of a single frame, and compressing and outputting the synthesized image (compressing and outputting step).

2. The method as defined in claim 1 further comprising the step of detecting the

values of the pixels for the respective sub-images after the differentiation and

substituting a value of zero for a pixel whose pixel value lies within a predetermined

difference from a value of zero.

3. The method as defined in claim 2 further comprising the step of comparing the

pixel values of each sub-image with those of the reference image after the execution of

the substituting step to substitute a value of zero for a pixel of each sub-image whose

pixel value lies within a predetermined difference from the pixel value of the relevant

pixel of the reference image.

4. An apparatus for performing the method of claim 1.

5. An apparatus for performing the method of claim 2.

6. An apparatus for performing the method of claim3.

7. A process method for compressing moving pictures, wherein a reference image and a plurality of sub-images each having a value differentiated from the

reference image and a resolution lower than that of the reference image are synthesized

to be compressed into the compressed image of a single frame, and the compressed

image is decoded and outputted, comprising the steps of: separating the reference image and respective sub-images from the

compressed image for arrangement along a time axis (arranging step); expansively interpolating the respective separated sub-images to the same

resolution as that of the reference image (expansively interpolating step); adding the value differentiated from the reference image to each expanded

sub-image (adding step); and alternatively and insertedly coupling the pixels of the horizontal and vertical

reference image onto a single frame according to a predetermined order, and synthesizing the same in an image of original resolution to be outputted (synthesizing and outputting step).

8. The method as defined in claim 7, wherein the expansively interpolating step further comprises the steps of: expansively interpolating the resolutions by copying neighboring pixels to increase the number of pixels (expanding step); detecting the lost pixel after the expansion of the resolutions (detecting step);

and applying to the lost pixel (op) an average (A) of a pixel value (f) thereof, a

pixel value (f-1) relative to the same position of a previous frame and a pixel value

(f+1) relative to the same position of a next frame (loss compensating step).

9. The method as defined in claim 8, wherein the loss compensating step further

comprises the step of comparing the "f, "f-1" and "f+1" and substituting the smallest

value of the three for the pixel (op) when the average (A) is less than f/2, (f-l)/2 or

(f+l)/2.

10. An apparatus for performing the method of claim 7.

11. . An apparatus for performing the method of claim 8.

12. An apparatus for performing the method of claim 9.

13. A process method for compressing moving pictures, wherein original images are compressed and outputted by encoding, comprising the steps of: reducing an original image by a predetermined fraction to conform to an output resolution and setting same as a reference image, and copying the reference

image in plural numbers and setting same as sub-images (setting step); erasing pixels from horizontal and vertical resolutions of each sub-image per

set order wherein the pixel erasing order is alternated for each sub-image such that a

pixel being erased is alternated for each sub-image (alternating step); arranging the reference image and the alternated sub-images along a time axis

in multiple frames (arranging step); differentiating the respective sub-images from the reference image

(differentiating step); deleting, from each sub-image, areas of vertical and horizontal resolutions

whose pixels are erased in the alternating step and coupling the remaining non-deleted

areas to thereby reduce the overall resolutions of each sub-image (reducing step); and arranging the reference image and the reduced sub-images in multiple frames along a time axis and compressing and outputting the same (arranging and compressing step).

14. The method as defined in claim 13 further comprising the step of pairing off the sub-images after the differentiation and synthesizing of the paired-off sub-images along the time axis (time axis synthesizing step).

15. The method as defined in claim 14, wherein the time axis synthesizing step

further comprises the step of averaging the pixel values of the paired-off sub-images

and substituting the averaged pixel value for the synthesized pixel value for generation

of the synthesized sub-images.

16. The method as defined in claim 15 further comprising a correction step

wherein, if the average is less than the half value of the pixel value (f) of the current

frame, the half value of the pixel value (f-1) relative to the same position of the

previous frame or the half value of the pixel value (f+1) relative to the same position of

the next frame, the "f ', "f-1" and "f+1" are mutually compared, and the smallest of the

three is substituted for the synthesized pixel value.

17. The method as defined in claim 13 further comprising a substituting step

wherein the values of the pixels for the respective sub-images after the differentiation

are detected and a value of zero is substituted for a pixel whose pixel value lies within

a predetermined difference from a value of zero.

18. The method as defined in claim 17 further comprising a substituting step wherein pixel values of each sub-image is compared with the pixel values of the reference image after the substituting step and a value of zero is substituted for a pixel of each sub-image whose pixel value lies within a predetermined difference from the

pixel value of the relevant pixel of the reference image.

19. An apparatus for performing the method of claim 13.

20. An apparatus for performing the method of claim 14.

21. An apparatus for performing the method of claim 15.

22. An apparatus for performing the method of claim 16.

23. An apparatus for performing the method of claim 17.

24. An apparatus for performing the method of claim 18.

25. A process method for compressing moving pictures wherein a reference image

and a plurality of sub-images each having a differentiated value from the reference

image and a resolution lower than that of the reference image are compressed into

respective frames and the compressed respective frames are arranged along a time axis

and decoded to be outputted, comprising the steps of: separating the reference image and the respective sub-images from the

compressed images (separating step); expansively interpolating the respective separated sub-images to the same

sub-image (adding step); and alternatively coupling the pixels of the horizontal and vertical resolutions of

an image of original resolution (synthesizing and outputting step).

26. The method as defined in claim 25, wherein the expansively interpolating step

further comprises the steps of: copying neighboring pixels to increase the number of pixels and to

expansively interpolate the resolutions; detecting the lost pixels following the expansion of the resolutions; and comparing the correlation of pixels per vertical and horizontal resolution between the neighboring front frame and rear frame and taking a pixel of higher correlation to correct the omitted data of the lost pixel.

27. An apparatus for performing the method of claim 25.

28. An apparatus for performing the method of claim 26.

29. A process method for compressing moving pictures wherein an original image

is encoded, compressed and outputted, comprising the steps of: reducing an original image of a current frame to conform to an output

resolution to a predetermined fraction and setting same as a reference image, and

copying the reference image in plural numbers and setting same as sub-images (setting

step); reducing original images of a previous frame and a next frame and copying

same in plural numbers and setting same as sub-images (setting step); erasing pixels from horizontal and vertical resolutions of each sub-image at a

step); arranging the reference image and the alternated sub-images in multiple

frames along the time axis (arranging step); differentiating the respective sub-images from the reference image (differentiating step); and arranging the reference image and the respective differentiated sub-images in

multiple frames along the time axis, and compressing and outputting same

(compressing and outputting step).

30. The method as defined in claim 29 further comprising the step of pairing off

the respective sub-images after the differentiation to synthesize the paired-off sub-

images along the time axis.

31. The method as defined in claim 30, wherein the time axis synthesizing step

generates a synthesized sub-image by averaging the paired-off sub-images and

substituting the average for a synthesized pixel value.

32 An apparatus for performing the method of claim 29.

33 An apparatus for performing the method of claim 30.

34. An apparatus for performing the method of claim 31.

35. A process method for compressing moving pictures wherein a reference image and a plurality of sub-images each having a differentiated value from the reference image and a resolution lower than that of the reference image are compressed into

compressed image (separating step); adding the value differentiated from the reference image to each said separated

sub-image (adding step); and alternatively coupling the pixels of horizontal and vertical resolutions of the

reference image and each sub-image to which the differentiated value is added on a

single frame according to a predetermined order and compressing and outputting same

as an image of original resolution (compressing and outputting step).

36. An apparatus for performing the method of claim 35.