Pulse or digital communications – Bandwidth reduction or expansion – Television or motion video signal
Reexamination Certificate
1999-08-17
2004-02-10
Kelley, Chris (Department: 2613)
Pulse or digital communications
Bandwidth reduction or expansion
Television or motion video signal
Reexamination Certificate
active
06690724
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an image processing method, an image processing apparatus, and a data recording medium and, more particularly to hierarchical coding and hierarchical decoding wherein an image signal is recorded or transmitted with fewer bits without degrading an image quality, and a recording medium which stores a program for implementing the hierarchical coding or the hierarchical decoding.
BACKGROUND ART
In order to perform image processing for each object displayed on a display image, a shape signal indicating a shape of an object as well as a luminance signal and a chrominance signal is necessary as an image signal. In description below, the image signal comprising the shape signal, i.e., shape information of the object, as well as the luminance signal and the chrominance signal is referred to as the “image signal”.
This image signal is suitable for use in multimedia in which image information, audio information and so forth are related to each other simultaneously, since it can be handled for each object. Techniques for coding the image signal is currently standardized by MPEG (Moving Picture Experts Group) 4 as ISO/IEC (International Organization for Standardization/International Electrotechnical Commission Joint Technical Commission) group.
A prior art hierarchical coding of the image signal will now be described.
FIG. 22
shows display images (hereinafter referred to as “frames”) corresponding to image signals of different resolutions, respectively. In FIG.
22
(
a
), LF indicates a display image of a low-resolution image signal and in FIG.
22
(
b
), HF indicates a display image of a high-resolution image signal. Lob represents an image of an object of the low-resolution image signal which is displayed on the frame LF. Hob indicates an image of an object of the high-resolution signal which is displayed on the frame HF. In these Figures, an inner portion of each object is represented by dots.
In the prior art image coding (state of the art evaluation model system according to MPEG 4), a rectangular region including an object is set on a frame for each object and the rectangular region is divided into blocks (square blocks MB each comprising (16×16) pixels in the evaluation model according to MPEG 4). The image signal corresponding to each object is coded for each of the blocks composing the rectangular region.
Hence, in the hierarchical coding according to MPEG4, a low-resolution rectangular region LR is set for an object Lob on a low-resolution frame LF as shown in FIG.
22
(
c
) and a high-resolution rectangular region HR is set for an object Hob on a high-resolution frame HF as shown in FIG.
22
(
d
).
In this hierarchical coding, the rectangular region LR for the low-resolution image signal and the rectangular region HR for the high-resolution image signal are respectively and independently set. As a result, in some cases, although coding itself is performed with ease, spatial positions of respective blocks of each object (positions of respective blocks on the frame) do not match between blocks in the low-resolution rectangular region and blocks in the high-resolution rectangular region and therefore, correspondence does not exist between them.
Hereinafter, this will be described in detail.
FIG. 23
is a block diagram showing a prior art hierarchical image coding apparatus.
A prior art image coding apparatus
200
a
is adapted to receive an input image signal and perform hierarchical coding to the input image signal as a high-resolution image signals HSg. To be specific, the hierarchical image coding apparatus
200
a
comprises a subsampling unit
2
for subsampling the high-resolution image signal HSg to produce a low-resolution image signal LSg, and a low-resolution coding section
201
L for performing coding to the low-resolution image signal LSg to produce a low-resolution coded signal LEg. The apparatus
200
a
further comprises a decoder
9
a
for decoding the low-resolution coded signal LEg, an upsampling unit
10
a
for upsampling an output Ldg of the decoder
9
a
, and a high-resolution coding section
201
H for performing coding to the high-resolution image signal HSg on the basis of an output LAg of the upsampling unit
10
a
and outputting a high-resolution signal HEg.
The low-resolution coding section
201
L includes a region detecting unit
3
for detecting information such as a position or a size of the low-resolution rectangular region LR for each object on the low-resolution frame LF on the basis of the low-resolution image signal LSg and outputting the information as a signal LRg, and a region extracting unit
5
for extracting an image signal LOg (image signal corresponding to a region) of the rectangular region LR from the low-resolution image signal LSg according to the signal LRg. The coding section
201
L further includes a blocking unit
6
for dividing the image signal LOg of the rectangular region LR into image signals respectively corresponding to blocks MB each comprising (16×16) pixels into which the rectangular region is divided, and outputting image signals (blocked image signals) LBg for each block, and an encoder
7
for encoding the blocked image signal LBg and outputting a low-resolution coded signal LEg.
The high-resolution coding section
201
H includes a region detecting unit
12
for detecting information such as a position or a size of the rectangular region HR for each object on the high-resolution frame HF on the basis of the high-resolution image signal HSg and outputting the information as a signal HRg and an region extracting unit
14
for extracting an image signal HOg of the rectangular region HR from the high-resolution image signal HSg according to the signal HRg. The coding section
201
H further includes a blocking unit
15
for dividing the image signal (image signal corresponding to a region) HOg of the rectangular region HR into image signals respectively corresponding to blocks MB each comprising (16×16) pixels into which the rectangular region is divided, and outputting image signals (blocked image signals) HBg for each block, and an encoder
16
for encoding the blocked image signal HBg and outputting a high-resolution coded signal HEg.
Subsequently, operation will be described.
When the high-resolution image signal HSg is input to the image coding apparatus
200
a
as the input image signal, the signal HSg is subjected to subsampling and converted into the low-resolution image signal LSg by the subsampling unit
2
.
The region detecting unit
3
of the low-resolution coding section
201
L detects a range of the rectangular region LR including the object Lob to be processed on the low-resolution frame FL shown in FIG.
22
(
c
) on the basis of the low-resolution image signal LSg and outputs the information such as a position or a size of the rectangular region as the signal LRg. The region extracting unit
5
extracts the object image signal LOg of the rectangular region LR from the low-resolution image signal LSg according to the signal LRg. The blocking unit
6
divides the object image signal LOg into image signals respectively corresponding to plural blocks MB into which the low-resolution rectangular region LR is divided, and outputs blocked image signals LBg corresponding to respective blocks to the encoder
7
. The encoder
7
encodes the blocked image signal LBg, and the low-resolution coded signal LEg is output from the coding section
201
L.
The low-resolution coded signal LEg is decoded by the decoder
9
a
and converted into a low-resolution decoded signal Ldg, which is interpolated and converted into an interpolated decoded signal LAg with the same spatial resolution as the high-resolution image signal and output to the encoder
16
in the high-resolution coding section
201
H.
Concurrently with this operation, the high-resolution coding section
201
H operates like the low-resolution coding section
201
L.
To be specific, the region detecting unit
12
detects a range of the rectangular region HR including an object Hob to be processed on the
Kelley Chris
Senfi Behrooz
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Image processing method, image processing device, and data... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image processing method, image processing device, and data..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image processing method, image processing device, and data... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3349038