Image analysis – Color image processing – Color correction
Reexamination Certificate
1999-08-25
2001-10-09
Johnson, Timothy M. (Department: 2623)
Image analysis
Color image processing
Color correction
C382S264000
Reexamination Certificate
active
06301384
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to digital color image signal processing. The present invention is applicable to still-frame pictures and motion pictures.
BACKGROUND OF THE INVENTION
The advent of the Internet and improvements in computer technology have lead to more frequent transmission of color image data via computer networks and to the display of color images on computers or like devices. It is expected that the use of computers for displaying color image data and the need to enhance image quality will continue to increase, particularly as computers and like devices are used to display motion pictures.
Various filter and image data processing circuits/logic have been developed to support advances in digital color image data processing. These circuits/logic include color, contrast, brightness and related circuits/logic.
Color image data is typically generated by subjecting raw image data to a compression algorithm. The compressed data can be more rapidly transmitted and/or more efficiently stored than non-compressed data. The compressed data is decompressed and interpolated for display.
During compression (and due to other causes), defects may be introduced into color image data. These defects often take the form of holes or graininess in a displayed image. Decompression and interpolation algorithms may also contribute to these defects.
In an effort to reduce image defects and to generally improve image quality, color filter circuits/logic have been developed. In a parallel filtering arrangement, separate filters operate on each of the three primary color signals. This results in rapid processing, but necessitates a large amount of processing circuitry. In a serial filtering arrangement, each color signal is fed serially through the same filter circuitry. While serial arrangements decrease the requisite amount of circuitry by approximately two-thirds compared to parallel arrangements, serial arrangements increase processing time approximately three-fold.
In addition to noise and defect reduction, filters also reduce the clarity or sharpness of an image. Thus, by filtering each of the color signals, a cumulative reduction in image clarity is produced.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide filtering of color image data in a manner that requires less circuitry and/or processing time.
It is another object of the present invention to achieve this filtering in a manner that causes less image clarity reduction.
It is another object of the present invention to provide filtering of less than all of the primary colors of a color image data signal.
It is also an object of the present invention to provide filtering of the color or colors to which the human eye is most sensitive.
These and related objects of the present invention are achieved by use of an improved color image data processing apparatus and method as described herein.
In one embodiment, the present invention includes logic and/or a method for color image data processing in which the green color signal is filtered while the blue and red color signals are not filtered. The human eye is most sensitive to the color green. As a result, filtering this color produces the largest amount of recognizable noise reduction (or otherwise stated image quality enhancement) per primary color signal. By filtering only one of the primary colors (or less than all), the amount of processing circuitry and/or the amount of processing time is significantly reduced.
Furthermore, by not filtering the blue and red components (or by not filtering at least one of these components), the sharpness contained in the unfiltered component is contributed to the final image signal. Thus, a reduced noise, sharper contrast signal from minimal circuitry and processing is achieved.
It should be recognized that other primary color schemes (e.g. CMYK or YUV, etc.) may be utilized, without departing from the present invention's teaching of filtering less than all of the primary color signal components, and preferably (but not necessarily) filtering the color or colors to which the human eye is most sensitive. It should also be recognized that while filtering one of the color signals is preferred, filtering more than one, but less than all is also within the present invention.
The attainment of the foregoing and related advantages and features of the invention should be more readily apparent to those skilled in the art, after review of the following more detailed description of the invention taken together with the drawings.
REFERENCES:
patent: 4663661 (1987-05-01), Weldy et al.
patent: 4689666 (1987-08-01), Hatanaka
patent: 4962419 (1990-10-01), Hibbard et al.
patent: 5557339 (1996-09-01), Dadourian
patent: 5667474 (1997-09-01), Nishimura
patent: 5715015 (1998-02-01), Lee
Adamson Steven J.
Johnson Timothy M.
NuWave Technologies, Inc.
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