Image analysis – Image compression or coding
Reexamination Certificate
1998-06-05
2001-04-03
Couso, Jose L. (Department: 2724)
Image analysis
Image compression or coding
C382S236000, C358S435000
Reexamination Certificate
active
06212300
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an image processing apparatus, method and computer-executable program product for converting the format of data for specific image data, and in particular, for converting the order of pixel data supplied in a predetermined format.
2. Description of the Related Art
A compression method with Discrete Cosine Transform (DCT), such as JPEG, has been used for compressing digital image data. Using DCT compression technique, it is necessary to divide image data into block form image data of a predetermined size, as shown in FIG.
1
. When using the JPEG method, image data is divided into blocks of 8 pixels×8 pixels. Therefore, it is usually necessary to provide a buffer memory which is capable of storing image data of at least 8 lines to perform DCT in real time. Further, when raster image data is compressed in real time, it is necessary to use another buffer memory which hold the image data from image processor while the raster image data is divided into blocks.
However, conventionally, it is not possible to perform data format conversion efficiently. In particular, in a case where the raster image data is composed of plural components, the data format conversion becomes very inefficient.
SUMMARY OF THE INVENTION
The present invention addresses the above-mentioned shortcomings by performing block/raster conversion on color image data efficiently.
In one aspect, the present invention is an image processing apparatus which converts image data between a raster form and a block form, which comprises means for supplying image data having a plurality of components in a first form, means for changing the order of the plurality of components, and means for controlling storing of a memory which stores the image data temporarily such that the image data is stored in the memory for each component and is read out from the memory in a second form which is different from the first form.
Preferably, the first form is raster form and the second form is block form having a predetermined size.
The changing means changes the order of the components such that the components are output for each component in a predetermined unit.
The components are stored in different areas of the memory for each component.
More preferably, the apparatus further includes means for performing orthogonal transformation on the image data which is read out from the memory, the reading access of the memory means is performed in units of the block of the orthogonal transformation.
The control means controls storing of the image data to the memory means such that writing of the image data is prohibited in a predetermined time after the image data of a predetermined lines is written into the memory.
The predetermined time is a time which is necessary for reading the image data of one block unit of the orthogonal transformation.
The apparatus further comprising means for quantizing the image data which is transformed by the transforming means and means for performing variable-length coding on the image data output from the quantizing means.
This summary has been provided so that the nature of the invention may be understood quickly. A more complete understanding of the invention can be obtained by reference to the followed detailed description of the preferred embodiments thereof in connection with the attached Figures.
REFERENCES:
patent: 5467413 (1995-11-01), Barrett
patent: 5875039 (1999-02-01), Ohsawa et al.
patent: B-66067 (1996-02-01), None
Canon Kabushiki Kaisha
Couso Jose L.
Do Anh Hong
Fitzpatrick ,Cella, Harper & Scinto
LandOfFree
Image processing apparatus, method and computer-executable... 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 apparatus, method and computer-executable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image processing apparatus, method and computer-executable... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2440052