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US 5,495,429 AGranted
Method and apparatus for measuring the color of three dimensional objects
AssigneeWest Virginia University
InventorsRobert P. M. Craven, William K. Preece, James E. Smith
Life of this patent
Estimating the term…
Abstract
A method for measuring color of objects comprises storing in a computer memory values representative of measurements of the color of an object over a range of angular positions with respect to a photosensor, selecting a measurement area of the object, determining a geometrical structure of the measurement area, and adjusting the measured color in response to the stored values. An associated apparatus is also provided.
Claims55
A method for measuring color of three dimensional objects, said method comprising the steps of:
- storing in a computer memory color measurement values of a sample having a color which corresponds to the color of the object to be measured;
- said measurement values representative of measurements of the color of said object taken with a color photosensor over a range of orientations of said object with respect to said photosensor;
- placing a three dimensional object to be measured within a viewing area of said photosensor;
- selecting a measurement area of said three dimensional object to be measured for color by said photosensor;
- illuminating said measurement area;
- determining a three dimensional geometrical structure of said measurement area relative to said photosensor by surface orientation sensing means operably coupled with said computer, converting said three dimensional geometrical structure into geometric structural information values and storing said geometric structural information values in the memory of said computer;
- employing said photosensor to obtain color information from said measurement area, converting said measured color information into color information values and storing said color information values in the memory of said computer;
- and
- adjusting in said computer said color information values in response to said stored sample values and said stored geometric structural information values in order to provide an adjusted measured color of said three dimensional object.
6 more elements
A method for determining a color value of a three dimensional object relative to a standard set of color values., said method comprising the steps of:
- storing said standard color values in a computer memory;
- associating each of said stored values with a corresponding angular position of a portion of said three dimensional object relative to a photosensor;
- introducing said three dimensional object into a viewing area of said photosensor;
- measuring at least a portion of said three dimensional object for color;
- determining an angular position of each pixel corresponding to said measured portion relative to said photosensor;
- and
- comparing the color value of said corresponding pixel to one of said stored color values at a corresponding angle.
4 more elements
A method for measuring the color of three dimensional objects, said method comprising the steps of:
- illuminating at least a portion of a three dimensional object with a light source;
- viewing at least a section of said illuminated portion with a photosensor wherein said photosensor is at a predetermined position relative to said light source and said three dimensional object;
- digitizing said viewed section into corresponding pixel sections with a frame grabber in a computer operably coupled with said photosensor;
- determining an angular position of said viewed section corresponding to each of said pixel sections relative to said photosensor and said light source;
- storing color data of the color of said three dimensional object in a memory of said computer, wherein said color data corresponds to a range of angular positions of the pixel sections of said three dimensional object with respect to said photosensor;
- and comparing each of the pixel sections of said digitized section to said stored color data corresponding to said angular position of said viewed section.
3 more elements
An apparatus for measuring the color of three dimensional objects, said apparatus comprising:
- photosensor means for viewing at least a portion of a three dimensional object at a known orientation to said three dimensional object and providing color information therefrom;
- illuminating means for illuminating at least said viewed portion of said three dimensional object, said illuminating means being at a known orientation to said three dimensional object;
- geometrical determining means for determining a three dimensional geometrical structure of said viewed portion of said three dimensional object with respect to said photosensor means;
- digitizing means operably coupled with said photosensor means and said geometrical determining means for digitizing said color information provided by said photosensor means and said three dimensional geometrical structure information provided by said geometrical determining means regarding said viewed portion of said three dimensional object;
- and
- computer means operably coupled with said digitizing means, said computer means including memory means for storing data representative of the color of a control sample over a range of angular orientations of said control sample with respect to said photosensor means, wherein said computer means adjusts said digitized color information with respect to said stored data and with respect to said three dimensional geometrical structure information in order to provide an adjusted measured color of said three dimensional object.
3 more elements
Dependencies are inferred from the claim text.