Facsimile and static presentation processing – Static presentation processing – Attribute control
Reexamination Certificate
1999-03-26
2002-05-07
Rogers, Scott (Department: 2624)
Facsimile and static presentation processing
Static presentation processing
Attribute control
C358S529000, C358S532000, C358S463000, C382S263000, C382S264000, C382S275000
Reexamination Certificate
active
06384937
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention broadly pertains to an image processing method and apparatus. More particularly, the present invention relates to an image processing method and apparatus, wherein image processing is carried out on color image signals, which have been obtained by reading a color image.
2. Description of the Prior Art
With techniques for reading a color image and reproducing the color image as a visible image, a color image having been recorded on photographic film, or the like, is photoelectrically read with a sensor, such as a charge coupled device (CCD), and red (R), green (G), and blue (B) three primary color image signals are thereby obtained. Various image processing operations are carried out on the image signals, and a visible image is reproduced on a recording material from the image signals, which have been obtained from the image processing. Systems for carrying out such techniques have been proposed, wherein a pre-scanning operation and a fine scanning operation are carried out. In the pre-scanning operation, a color image is scanned at coarse scanning intervals and is read photoelectrically. In this manner, the image information concerning the color image is approximately ascertained. Various parameters to be used in carrying out the image processing are set in accordance with the information, which has been obtained from the pre-scanning operation. Thereafter, the fine scanning operation is carried out. In the fine scanning operation, the color image is scanned at fine scanning intervals, and the R, G, and B three color image signals to be used for reproducing the visible image are obtained.
As the techniques for carrying out the image processing in the systems described above, for example, various techniques for enhancing the image sharpness by carrying out the image processing on the image signal, which represents a given image, have been proposed. As one of such techniques, a technique for enhancing the image sharpness by carrying out unsharp mask processing on the image signal has been proposed in, for example, “Image Analysis Handbook,” the publishing circle of the University of Tokyo, supervised by Mikio Takagi and Yokyu Shimoda, p. 549.
Also, a processing technique for suppressing the graininess of a reproduced image and enhancing the image sharpness has been proposed in, for example, U.S. Pat. No. 4,812,903. With the proposed processing technique, R, G, and B three color image signals are separated into a luminance signal and chrominance signals. Nonlinear processing is carried out on low frequency components of the luminance signal. Also, processing for enhancing high frequency components of the luminance signal is carried out. Thereafter, the luminance signal, which has been obtained from the processing, and the chrominance signals are combined together.
Further, a different image processing technique for enhancing the image sharpness and suppressing the image graininess has been proposed in, for example, Japanese Unexamined Patent Publication (Kokai) No. 63-26783. With the proposed image processing technique, a luminance signal and chrominance signals (representing the hue, the saturation, or the like) are extracted from image signals, which represent a color image. Spatial filter processing is carried out to the luminance signal to thereby obtain spatial general information and spatial detail information. Predetermined enhancement processing is then carried on the spatial general information and the spatial detail information. Thereafter, the spatial general information and the spatial detail information, which have been obtained from the enhancement processing, are combined together, and a new luminance signal is thereby obtained. The new luminance signal and the chrominance signals are then combined together and converted into predetermined color image signals. With the proposed image processing technique, a processed image can be obtained, which has been subjected to natural sharpness enhancement processing such that little change in the color tone, or the like, may occur, and in which the graininess has been suppressed.
Furthermore, as for ordinary analog photographs, it has been known that, in cases where a photograph is enlarged from 35 mm film, or the like, to a size of 203 mm×254 mm, 254 mm×305 mm, or larger, patterns of grains in the film become perceptible, depending upon colors, and the image quality deteriorates. Therefore, an image processing technique for suppressing the graininess of the output image has been proposed in, for example, Japanese Unexamined Patent Publication (Kokai) No. 1-277061. With the proposed image processing technique a predetermined color portion, such as a flesh-color portion, is extracted from a color image. In cases where the area of the predetermined color portion having thus been extracted becomes equal to a predetermined area or larger, noise removal processing is carried out on the predetermined color portion. In this manner, boundary lines between grains in the flesh-color or skin color region are removed, and the graininess of the output image is thereby suppressed.
Also, a technique for enhancing the image sharpness has been proposed in, for example, Japanese Patent Application Publication (Kokai) No. 3-502975. With the proposed technique, the image sharpness is enhanced by changing the value of a coefficient K in the formula for unsharp mask processing, which is shown below, in accordance with a characteristic portion of the image.
S′=S
org
+K·(S
org
−S
us
)
wherein S
org
represents the original image signal, and S
us
represents the unsharp mask signal. Specifically, with the proposed technique, local variance values, which are plotted with respect to the frequency of occurrence, are calculated as for a flat portion of the image, in which the level of noise due to the film graininess is high, a texture portion of the image, and an edge portion of the image. The value of the coefficient K is set as functions of the local area limited variance values.
However, with the techniques described above, a reproduced image having good image quality cannot be obtained. For example, with the unsharp mask processing described above, the sharpness can be enhanced. However, the unevenness due to the film graininess is also enhanced together with the enhancement of the sharpness. As a result, a reproduced image having good image quality and little noise cannot be obtained. With the technique proposed in U.S. Pat. No. 4,812,903 or Japanese Unexamined Patent Publication (Kokai) No. 63-26783, wherein the high frequency components of colors are not enhanced, the uneven feeling due to the film graininess can be suppressed to be lower than with the unsharp mask processing. However, unevenness of the luminance components due to the film graininess still remains unremoved. With the technique proposed in Japanese Unexamined Patent Publication No. (Kokai) 1-277061, noise due to the film graininess can be removed. However, the image sharpness cannot be enhanced and, as a result, a reproduced image which is easy to view cannot be obtained.
With the technique proposed in Japanese Patent Application Publication (Kokai) No. 3-502975, noise due to the film graininess can be suppressed, and the sharpness can be enhanced. However, the local variance values of the texture portion, the edge portion, or the like, in which the amplitude of the image signal is small, cannot be easily separated from the local variance values of the flat portion. Therefore, it often occurs that the texture and the edge, which are to be reproduced with a high sharpness, are suppressed in the same manner as that for noise in the flat portion.
In contrast, the applicant has proposed an image processing apparatus and method for suppressing graininess due to a film and enhancing sharpness in Japanese Unexamined Patent Publication (Kokai) No. 9-22460. In an image signal representing an ordinary image, the components, which have effects upon the sharpness of the reproduce
Birch & Stewart Kolasch & Birch, LLP
Fuji Photo Film Co. , Ltd.
Rogers Scott
LandOfFree
Image processing method and apparatus 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 and apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image processing method and apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2909942