Computer graphics processing and selective visual display system – Computer graphics processing – Attributes
Reexamination Certificate
2000-06-22
2004-08-10
Chow, Dennis-Doon (Department: 2675)
Computer graphics processing and selective visual display system
Computer graphics processing
Attributes
C345S593000, C345S603000, C358S515000, C358S518000, C382S162000
Reexamination Certificate
active
06774909
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of and a system for transforming a color image to a monochrome image and a recording medium with a computer program for implementing transformation of a color image to a monochrome image.
2. Description of Related Art
In an extraction process of extracting a specific part from a color image, it is important to discriminate a specific area from the color image. It is popular to recognize a specific area of an image as a partial image having even characteristic values of color density, color, texture and the like. A technique of discriminating an image area from an entire image on the basis of color components as characteristic values is widely used in various industrial fields. In, for example, a food industry or a chemical industry, the image area discrimination technique is used in image discriminating devices for position inspection of a color label on a product, devices for screening products by recognizing a color bar printed on the product or a package of the product in a combined manufacturing line, and the like.
In such a device, an image pick-up device such as a color camera is used to pick up a color image of a subject product. The color image is transmitted to an image processing device in the form of analogue signals of three primary colors of picture elements of a color image, namely R (red), G (green) and B (blue) analogue image signals, which are then converted to R, G and B digital image signals and stored in a memory. The image processing device processes the R, G and B digital signals to display a color image on a display such as a cathode ray tube (CRT). For extraction of a color in the color image, one of the colors is selected on a color pallet by a mouse pointer, or a color for extraction is designated by R, G and B brightness values through a data entry device. Otherwise a color for extraction is designated by selecting directly one or more picture elements that have the color for extraction. When a color for extraction is determined, threshold levels are established to sort out picture elements having R, G and B brightness less than the threshold levels, respectively, for consistency in color with the extracted color. Areas enclosing the picture elements that are identified as having colors regarded consistent with the extracted color are given a specific brightness value of 0 (zero) or 1 (one), and the remaining areas are given a specific brightness value of 1 (one) or 0 (zero) so as to convert the color image to binary brightness data. In an area of the color image either one of the brightness values 0 and 1 is displayed on the CRT screen. In this image discriminating technique, when picking up an image of a color label attached to a rounded subject such as a chemical tube by a camera, light rays usually impinge against the subject at an angle, so as to illuminate unevenly over the color label. As a result, the color label shows shades, which make it impossible to recognize the entire area of the color label to be consistent in color, so that extraction of the entire area of the color label is not consistent. Further, when establishing high threshold levels for R, G and B brightness values for extraction of the entire area of a color label, there is the apprehension that an unnecessary area is possibly extracted. Further, uneven illumination causes uneven brightness distribution over a subject, which results in extraction of patchy areas. When establishing high threshold levels for R, G and B brightness values for extraction of the entire area of the subject, there is also the apprehension that an unnecessary area is possibly extracted.
In order to eliminate these problems, there has been proposed a technique of discriminating an image area from an entire image in which the utilization is made of three attributes of color. Specifically, R, G and B digital image signals converted from R, G and B analogue image signals of picture elements of an image of a subject are converted to three attribute values of color, namely, values relating to hue (H), saturation (S) and brightness (I). For extraction of a color in the color image, one of colors is selected on a color pallet by a mouse pointer, or a color for extraction is designated by R, G and B brightness values through a data entry device, or otherwise, a color for extraction is designated by selecting directly one or more picture elements that have the color for extraction. When a color for extraction is determined, threshold levels are established to sort out picture elements having H, S and I values less than the threshold levels, respectively, for consistency in color with the extracted color. Areas enclosing the picture elements that are identified as having colors regarded consistent with the extracted color is extracted and displayed on a CRT screen. The color image extraction provides a precise color appraisal with components of a color tone of a subject that is not affected by uneven illumination. Such a color image extraction is known from, for example, Japanese Unexamined Patent Publication No. 4-10075.
This color image extraction disclosed by the publication has the necessity of converting R, G and B brightness values to H, S and I values, so as to make the system construction complicated and to require intricate operation, which is always undesirable for improvement of operation speed. Further, on the grounds that, when the threshold level has been established once, an extraction area is unconditionally determined, it is hard to establish a threshold level suitable for a precise extraction of a desired area.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method of and apparatus for transforming a color image to a monochrome image in which utilization is made of an extent of color consistency defined by R, G and B brightness values and at least one of brightness disparities of respective couples of two primary colors of each color picture element of a color image so as to execute high speed image processing of a color image that even includes shades or areas having uneven brightness due to uneven illumination, and to transform the color image to a monochrome image that enables an operator to make a precise extraction of a desired area from the monochrome image.
It is another object of the present invention to provide a method of and apparatus for transforming a color image to a monochrome image which make it easy to recognize an extraction area in a monochrome image and to change an extraction area.
It is still another object of the present invention to provide a method of and apparatus for transforming a color image to a monochrome image which makes it possible to execute a precise extraction of black area in a monochrome image.
It is a further object of the present invention to provide a record medium which bears a program for causing a computer to operate an apparatus for transforming a color image to a monochrome image for establishing an extent of color consistency defined by R, G and B brightness values and at least one of brightness disparities of respective couples of two primary colors of each color picture element of a color image, executing high speed image processing of a color image that even includes shades or areas having uneven brightness due to uneven illumination, and transforming the color image to a monochrome image that enables an operator to make a precise extraction of a desired area from the monochrome image.
The foregoing objects of the present invention are accomplished by a method of transforming a color image to a monochrome image on the basis of values relating to brightness of three primary colors, namely red (R), green (G) and blue (B), of the color image which comprises the steps of: detecting R, G and B brightness of color picture elements of a color image; computing at least one of brightness disparities (R−B), (R−G) and (B−G) of respective couples of two primary colors of each color picture element; desig
Chow Dennis-Doon
Keyence Corporation
Kilyk & Bowersox P.L.L.C.
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