Surgery – Diagnostic testing – Measuring or detecting nonradioactive constituent of body...
Reexamination Certificate
1998-12-18
2001-01-23
Winakur, Eric F. (Department: 3736)
Surgery
Diagnostic testing
Measuring or detecting nonradioactive constituent of body...
C356S406000
Reexamination Certificate
active
06178341
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to techniques for measuring with a Color Measurement System and evaluating the color of skin, teeth, hair and material substances with a Color Index. The invention also relates to techniques for using such a Color Measurement System with the Color Index in medical applications such as the detection of chromogenic disease including bilirubin infant jaundice, cosmetics applications and in the evaluation of the color of hair or teeth and other applications.
It is well known that color measuring instruments, such as spectrocolorimeters and spectrophotometers, can be used to measure the color of surfaces for a variety of useful applications. For example, Macfarlane et al. U.S. Pat. No. 5,313,267 describes a method and instrument for selecting personal compatible colors using a color measuring device. Also, PCT Publication No. WO 96/41140 describes methods and apparatus for determining the condition of a test subject based on color by using a color measuring instrument to detect change in a color factor indicative of a condition such as a disease, spoilage, ageing, etc. In particular, those methods and apparatus can be used to detect a medical condition known as hyperbilirubinemia by measuring skin color.
However, in order to accurately categorize skin versus each other (or teeth, hair or material substances, respectively), it is important that the Color Index used by the Color Measurement System for evaluating the color of skin, teeth, hair and material substances be independent of the illuminating condition and need not be calculated with respect to some standard illuminating condition. The alternative, allowing the Color Index to be dependent upon the conditions of illumination, would allow one sample (such as skin) to be categorized in one illuminating condition and another sample (such as skin) to be categorized in another illuminating condition, preventing any useful correlation of the colors of the two measurements.
It would be beneficial to develop a Color Measurement System for evaluating the color of skin, teeth, hair and material substances with a Color Index for skin, teeth, hair and material substances that makes a unique formulation of the opponent process of human vision. It is known that the contribution of redness and of greenness are in opponency to each other. Similarly, it is also known that the contribution of yellowness and of blueness are in opponency to each other. In other words, no color can exhibit qualities of redness and greenness at the same time, nor can a color exhibit qualities of yellowness and blueness at the same time. It would thus be beneficial to develop a Color Index for skin, teeth, hair and material substances that makes a unique formulation of the opponent process of human vision.
It would also be beneficial to develop a Color Measurement System for evaluating the color of skin, teeth, hair and material substances with a unique Color Index which is measured and calculated from the contribution of the reflectance spectrum of any skin (or teeth, hair, or material substance) to the appearance of four opponent colors, i.e., red-green and yellow-blue.
Furthermore, it would also be beneficial if the opponent process of human vision be formulated linearly with respect to the opponent contributions to color appearance rather than as an exponential function of the contributions as is conventionally held necessary for opponent-type systems.
In view of the foregoing, it is an object of this invention to provide a Color Measurement System for evaluating the color of skin, teeth, hair and material substances with a Color Index.
It is another object of this invention to provide a Color Measurement System for evaluating the color of skin, teeth, hair and material substances with a Color Index, wherein the Color Index is calculated from the contribution of the reflectance spectrum of any skin (or teeth, hair, or material substance) to the appearance of four opponent colors, i.e., red-green and yellow-blue.
It is yet another object of this invention to provide a Color Measurement System for evaluating the color of skin, teeth, hair and material substances with a Color Index that makes a unique formulation of the opponent process of human vision.
It is another object of this invention to provide a Color Measurement System for evaluating the color of skin, teeth, hair and material substances with a Color Index in which the opponent process is formulated linearly with respect to the opponent contributions to color appearance rather than as an exponential function of the contributions.
It is another object of this invention to provide a Color Measurement System for evaluating the color of skin, teeth, hair and material substances with a Color Index that is independent of the illuminating condition.
SUMMARY OF THE INVENTION
These and other objects of this invention are accomplished in accordance with the principles of the invention by providing a Color Measurement System for evaluating the color of skin, teeth, hair and material substances with a Color Index.
The Color Measurement System and Color Index for skin, teeth, hair and material substances of this invention is a unique Color Measurement System and Color Index measured and calculated from the reflectance spectrum of any skin (or teeth, hair or material substance). Uniquely, this invention's Color Measurement System and Color Index for Skin, Hair, and Material Substances is independent of the illuminating condition, as is necessary to accurately categorize skins versus each other (or teeth, hair or material substances respectively) in all illuminating conditions.
In accordance with the principles of this invention, the Color Index is measured and calculated from the reflectance spectrum of any skin (or teeth, hair or material substance) by a two step process. The first step is the weighting of the visible spectra with a unique set of weighting factors which calculate the contribution of the reflectance spectrum of any skin (or teeth, hair or material substance) to the appearance of four opponent colors, i.e., red-green and yellow-blue.
Conventionally, contributions to color appearance such as these were calculated with respect to some standard illuminating condition. Uniquely, the Color Measurement System and Color Index for skin, teeth, hair and material substances of this invention is independent of the illuminating condition.
The second step in measuring and calculating the Color Index in accordance with the principles of this invention places the contribution of the reflectance spectrum of any skin (or teeth, hair, or material substance) to the appearance of four opponent colors, i.e., redness-greenness and yellowness-blueness in opponency to each other. The Color Index in accordance with the principles of this invention is calculated from the contribution of the reflectance spectrum of any skin (or teeth, hair or material substance) to the appearance of four opponent color components and provides attributes representative of correlates of lightness-darkness (L, also referred to as lightness), redness-greenness (M) and yellowness-blueness (N).
According to one embodiment of this invention, evaluating color includes:
A method for evaluating color of a sample using a Color Measurement System with a Color Index, said method comprising:
measuring said sample's reflectance spectrum using a color measuring instrument;
weighting of said reflectance spectrum with weighting factors corresponding to four color components that form two opponent pairs of color components wherein said weighting factors are used to calculate said sample's reflectance spectrum's contribution to said four color components' appearance; and
determining individual contributions corresponding to each of said four color components and calculating said Color Index using said individual contributions and respective contributions to each of a respective one of said four color components by a perfect diffuser, said determining comprising:
summing said sample's r
Billmeyer, Jr. Fred W.
Fairman Hugh S.
MacFarlane Darby S.
MacFarlane David K.
Chromatics Color Sciences International Inc.
Fish & Neave
Mohan Brajesh
Winakur Eric F.
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