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“ True C o l o r s ”. Handheld Color Scanner. Presented by David Harwood Project Advisor: John Spinelli. Color Vision Deficiency. Deep Red. Medium Red. Deep Red. Brown. Deep Red. Brown. Deep Red. Brown. Finally, there is an answer…. “ True C o l o r s ”. Physical Design Goals.
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“True Colors” Handheld Color Scanner Presented by David Harwood Project Advisor: John Spinelli
Color Vision Deficiency Deep Red Medium Red Deep Red Brown Deep Red Brown Deep Red Brown
Finally, there is an answer… “True Colors”
Physical Design Goals • Portable and concealable • Weight < 140g (about 5oz) • Length = 120mm (about 4.7in) • Height = 60mm (about 2.4in) • Width = 30mm (about 1.2in) • 5mm measurement area • Usability • Minimal controls • Point-and-shoot operation
Functional Diagram control function camera processor screen reflected incident light source
Processing of Data • Reflected wavelengths are acquired • Wave characteristics determined • RGB values • Munsell color system - Value - Hue - Saturation
Processing of Data (Cont’) • Characteristics compared to color library • Standardized Munsell chart HSV • Color name assigned to scanned surface Hue = 0.050 = red Hue = 0.250 = yellow Hue = 0.403 = green Hue = 0.775 = blue … dominant color: RED Hue = 0.440
Light Source • Boxed encasing with white LED • Controlled environment • Limitations: emission spectrum is blue-light biased
Color Namesfrom Munsell Color System • 10 Basic Colors • Red • Orange • Yellow • Yellow-Green • Green • Blue-Green • Blue • Purple • Red-Purple • Brown
Standardized vs. Measured Hue Values for Prototype Moderate Red Yellow-green Blue-green Blue Sky Blue Flower Orange-Yellow Blue Magenta Orange Purple Yellow Green Cyan Red 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Standardized Hues Measured Hues 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Hue Sensitivity Distance Between Hue Values (dimensionless) Blu-2-Prp Org-2-Yel Red-2-Org Grn-2-BluGrn YelGrn-2-Grn BluGrn-2-Blu Prp-2-RedPrp RedPrp-2-Red Yel-2-YelGrn
Results 14.5/21 = 69% accuracy Explained by Sensitivity Figure
Goals • provide color label • input output time < 3sec • easily concealable • marketable price < $150.00 • appropriate library size
Achievements • Concept proven • Provided a reliable color label for most surfaces • Errors between similar colors • Simple color library • Minimal costs for prototype
Further Development • Light sensor as opposed to digital camera • A to D converter • MATLAB C • Microprocessor • LCD • Find a way to measure color of distant objects • Traffic lights • Unreachable items • Focusing lens • Sample smaller areas • Resistor values