Optics: measuring and testing – Standard – Surface standard
Reexamination Certificate
2000-04-05
2002-08-20
Winakur, Eric F. (Department: 3736)
Optics: measuring and testing
Standard
Surface standard
C356S421000, C600S310000
Reexamination Certificate
active
06437863
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to a method and apparatus for the detection and/or measurement of a condition that affects the color of a test subject, and more particularly to a process and instrument for measuring at least one color characteristic or factor of a test subject indicative of the condition of interest such as biological condition or hair coloration.
BACKGROUND OF THE INVENTION
Visual observation of a subject for changes in coloration indicative of a particular condition has often occurred. The subject may be a person or animal being observed to determine the presence or absence of a medical condition. The color characteristics or a single color characteristic of other test subjects such as biopsy specimens or excretions have diagnostic value.
An individual person's skin color is often assessed by her or his doctor. Hypertension, tuberculosis, sclerosis of the liver, to name just a few, are examples of ailments with symptomatic skin color changes among at least a sizeable population segment. Hair color evaluation and dental coloration evaluation are valuable. These may bear on the health of the individual, or on the health of the individual's hair and teeth, or these may permit accurate cosmetic activities, for example, to counteract graying or to accurately match new dental work to existing teeth.
Likewise, the condition of plants and agricultural products is visually inspected for color as an indication of condition. Contamination of soil is likewise apparent from visual inspection. Such visual inspections are subjective. Measuring by instrument the color characteristics that are key to the visual inspection has the benefit of objectivity and consistency.
In the past, hyperbilirubinemia in newborns has been detected by visually observing an individual for jaundice or by routinely taking and testing a blood sample. Upon detection, hyperbilirubinemia has been treated by phototherapy. During the course of phototherapy, blood samples have been taken and tested at regular intervals until it was determined that the level of serum bilirubin had decreased to an acceptable level.
In infants, there is little blood available for use in the blood testing for hyperbilirubinemia. So much blood is drawn that transfusions are often necessary to replace the drawn blood. The newborn is thereby exposed to all of the risks that transfusions bring. Blood sampling and transfusions are, of course, painful to the newborn, and as with any invasive procedure, both present medical risks, such as for example, risk of infection. There is a need, therefore, for a reliable, noninvasive technique for detecting and measuring a skin color affecting medical condition such as hyperbilirubinemia.
This is one example of a wider need for procedures and instruments to objectively and consistently determine a color characteristic or factor indicative of the condition of a test subject or indicative of a particular ailment or condition. The methods and apparatus of this invention can be employed where previously visual inspection, of which examples are given above, have been carried out at least in part on the basis of observable color characteristics.
This invention also relates to a method and apparatus for the categorizing of hair color and hair color treatment agents for their interrelationship, and more particularly to a process and instrument for measuring three color characteristics of hair color and categorizing it and determining the effect of a wide variety of hair coloring agents thereon.
Hair coloring agent choices are often made by a consumer based on relatively vague indications of the color to be expected as a result of the use of the agent on an individual person's hair. This approach does not take into consideration the color of the hair that is to be treated and how interaction of that particular individual's hair color with the coloring agent will affect the resultant color.
No reliable source of information has been available to a private consumer regarding what the actual color of her or his hair is and what hair coloring agent will provide the hair color alteration that consumer seeks.
Consequently it can be seen there exists a need for procedures and apparatus that will accurately characterize an individual's hair color to enable selection of appropriate coloring agents for a desired color result. Likewise there exists a need for a reliable process and instrumentation to permit the use of the accurate color characterization of an individual's hair color in the selection of hair coloring agents to effect hair color alterations of a type desired by the individual.
BRIEF SUMMARY OF THE INVENTION
According to this invention there is provided a method and apparatus for detecting and quantitatively measuring a condition affecting the color of a test subject. The method includes measuring at least one color characteristic of the subject.
In one exemplary procedure according to this invention at least one skin color characteristic is measured at least at first and second points in time. To test for hyperbilirubinemia, the two measurements are then compared for change. In the preferred procedure a second skin color characteristic is also measured on the basis of which the subject can be assigned to one of plural categories among which varying amounts of change in the first-mentioned skin color characteristic are indicative of the presence of a medical condition. The first characteristic is then observed for a change of measured value sufficient to indicate the medical condition for a subject in that category. Preferably, a base reading of at least the first color characteristic is first made at a time the subject is without characteristic skin coloration indicative of the medical condition for which he or she is to be tested.
In the case of hyperbilirubinemia detection, the first skin color characteristic is Hunter b, which is a color factor dependent on the relative content, in a color, of two opponent colors, yellow and blue. Hunter b is a factor comprising a first function (Y) weighted in a first portion of the spectrum, the yellower portion, a second function (Z) weighted in a second portion of the spectrum, the bluer portion, and a weighting term (1/Y
½
) that is a function of the lightness of a color and that decreases the value of the color factor as lightness increases. Y and Z are part of the three tristimulus values X, Y and Z known to the color scientist for the purpose of defining a color. They are measurable by commercially available instruments such as colorimeters.
In the case of testing newborns for hyperbilirubinemia, readings of Hunter b and the Hunter lightness measure L are made shortly after birth. These can provide the base reading since hyperbilirubinemia does not manifest itself immediately after birth. The first reading is preferably made within five hours, but as soon as possible after birth. Subsequent readings are then made during the next few days. The subsequent readings of Hunter b are compared with the first, baseline reading of Hunter b to determine whether Hunter b has increased to an extent that indicates a degree of jaundice characteristic of hyperbilirubinemia for a person having the range of the subject's particular skin lightness L. L is measured during each subsequent test to be sure that it remains close to the original reading. This gives a degree of confidence that the test procedures are being conducted appropriately.
In the event that the medical condition affecting skin color is detected in a procedure like that described above for hyperbilirubinemia, then the measuring of skin color characteristics continues at regular intervals until the symptomatic color characteristic abates sufficiently to indicate the individual's recovery from the medical condition. In the case of hyperbilirubinemia, phototherapy is administered once a sufficient change in Hunter b is observed to indicate the jaundice of hyperbilirubinemia. Throughout the course of phototherapy, then, the Hunter b a
Billmeyer, Jr. Fred W.
Macfarlane Darby Simpson
Macfarlane David Kenneth
Baker & Botts L.L.P.
Chromatics Color Sciences International Inc.
Winakur Eric F.
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