Colorimetric imaging system for measuring color and appearance

A system for quantifying color and appearance attributes of batch samples comprising:

• a camera for capturing an RGB image of a standard sample and at least one batch sample;
• an illumination source for illuminating said standard sample and said at least one batch sample;
• calibration means for calibrating said camera and said illumination source for the purpose of generating correction factors, wherein said calibration means comprises a dynamic range calibration standard, a non-uniformity calibration standard, a dual beam correction standard, and a colorimetric calibration standard, wherein said dynamic range calibration standard comprises a hollow rectangular box having an opening on the top side, an exterior white portion, and an interior black portion, wherein said white portion comprising a white tile mounted on the top side of said box adjacent to said opening, and said black portion comprising two pieces of black glass within said box mounted approximately 90 degrees to each other and approximately 45 degrees to incoming light entering said opening, wherein at least one measurement of said dynamic range calibration standard is captured and averaged to determine baseline measurements for said camera and said camera is adjusted if said baseline measurements are not within pre-defined tolerances;
• and
• computer processor means for controlling and compensating said camera, said illumination source, and said calibration means, measuring said standard sample and said at least one batch sample, digitizing said camera RGB image into RGB image data for said standard sample and said at least one batch sample, processing said digitized RGB image data from the RGB domain to the CIE XYZ tristimulus domain and then to the L*C*h color space domain, processing said digitized L*C*h color space data to determine appearance attributes, and comparing said at least one batch sample data to said standard sample data.

A method for quantifying color and appearance attributes of batch samples comprising the steps of:

• calibrating a camera and an illumination source for the purpose of generating correction factors, including the steps of a dynamic range calibration and a non-uniformity correction calibration, wherein said non-uniformity correction calibration comprises the steps of placing a uniform white standard within the field of view of said camera, obtaining at least one measurement of a non-uniformity correction calibration standard, averaging said at least one measurement of said non-uniformity calibration standard, calculating the average value of captured pixels in the R, G, and B image planes, dividing each pixel in the R plane by said average value of captured pixels in the R plane to create a two-dimensional map of correction factors, dividing each pixel in the G plane by said average value of captured pixels in the G plane to create a two-dimensional map of correction factors, dividing each pixel in the B plane by said average value of captured pixels in the B plane to create a two-dimensional map of correction factors, and storing the resultant non-uniformity correction factors which represent spatial non-uniformities present in every image captured;
• measuring a standard sample;
• measuring at least one batch sample;
• and
• comparing said color and appearance attributes of said at least one batch sample to said standard sample.

A system for quantifying color and appearance attributes of batch samples comprising:

• a camera for capturing an RGB image of a standard sample and at least one batch sample;
• an illumination source for illuminating said standard sample and said at least one batch sample;
• calibration means for calibrating said camera and said illumination source for the purpose of generating correction factors, including a dynamic range calibration standard, wherein said dynamic range calibration standard comprises a hollow rectangular box having an opening on the top side, an exterior white portion, and an interior black portion, wherein said white portion comprising a white tile mounted on the top side of said box adjacent to said opening, and said black portion comprising two pieces of black glass within said box mounted approximately 90 degrees to each other and approximately 45 degrees to incoming light entering said opening, wherein at least one measurement of said dynamic range calibration standard is captured and averaged to determine baseline measurements for said camera and said camera is adjusted if said baseline measurements are not within pre-defined tolerances;
• and
• computer processor means for controlling and compensating said camera, said illumination source, and said calibration means, processing said RGB image data, and comparing said at least one batch sample processed RGB image data to said standard sample processed RGB image data.