ColourIt Team Members:Julie Chao Linda Ni Bill Yang

Members of CoulorSense Inc. –Julie Chao, CEO –Linda Ni, Project Manager –Bill Yang, CTO Reveals True Colours Introduction of ColourSense Inc.

ColourIt –Background and Advantages –System Overview –Functionality –Design and Reasoning Final Stage Prototype –Usability and Reproducibility –Different Applications –Difficulties Encountered Future Work and Conclusion Reveals True Colours Overview

Reveals True Colours Vision Background Visual System in Human Eye –Retina: contains light receptors –Rods –Cones that absorbs red light (long-wavelength) –Cones that absorb green light –Cones that absorb blue light (short-wavelength)

Colour Model and Colour Space A colour model is an abstract mathematical model describing the way colours can be represented typically as three or four values or colour components. RGB (addictive colour mixing) and CMYK (subtractive colour mixing) are colour models. sRGB, Adobe RGB, HSV (hue, saturation, intensity) are colour spaces. addictive subtractive Reveals True Colours Colour Background

Reveals True Colours Introduction of ColourIt Area of Interest Colour Sensing Unit Central Control Unit User Interface Unit White LEDs Colour Sensor Micro- controller Reflected light LCD Screen RGB values 255, 0, 255 Block Diagram of Overall System

Reveals True Colours Power Specifications System Requirement: –Input 5.0V, load current 60mA Solution: –Input 9.0V, output 5.0V –+5V voltage regulator: LM341 (needs min 7.2V) –Battery: 9V, 625mAh (25X16X44mm) –Advantage: easy to implement, easily accessible battery –Cost: $4 battery, $1.50 chip

Reveals True Colours Sensor Unit Specifications White light must be evenly distributed 4 LEDs centred around sensor Dimensions: 20-25mm in diameter 13 mm height

Reveals True Colours Operation Flow Chart Initialization N Y Sample and display RGB values of colour on LCD N Y N Power on Sample? Hold more than 2 seconds? Toggle? White calibration Enable or disable illuminating LEDs Black calibration Y Y N Hold more than 2 seconds?

Reveals True Colours Purpose of White & Black Calibration Wavelength Output Frequency F white F black Colour Seen by Sensor = Colour of Target Surface Inner Wall Colour of Tube + Ideal F white Ideal F black

Reveals True Colours Coversion to RGB Wavelength Output Frequency F white F black F sample Range Delta B = Range Delta X 255  Same Calculation for R and G  Uncertainty = + _ 1

Reveals True Colours Correction Matrix X = M · T X = The corrected RGB values M = 3X3 correction matrix T = RGB values measured by ColourIt M can be approximated by using fminserch() function in Matlab to find the optimum correction matrix that minimize the sum of the root mean square errors of each RGB pairs in the X and T matrix Colour Checker

Reveals True Colours Colour Standards Book: Color Harmony by Cailin Boyle –Problems: Inconsistency, inaccuracy –Printing always effects actual colour Better: ColorChecker checkerboard –24 scientifically prepared colors –Objects of special interest (skin, foliage, sky) –Reflect light same way –Colours match natural objects under any illumination and with any color reproduction process

Reveals True Colours Desired Packaging Original vision Desired dimensions: less than 120X40X30 mm (body) Light, portable, compact Make use of existing parts –Pipes, flashlights, tubes, switchboxes, conduit bodies

Reveals True Colours Final Packaging Used conduit body: E986D Features: –Plastic –20 mm entry hole –Removable lid –Body dimensions: 77X27X26 Problems: –Barely enough space –Next size, E986E, triple of E986D –Solution: milled out interior

Reveals True Colours Demonstration Pink 255,192,203 Blue 0,0,255 Violet 238,130,238 Navy 0,0,128 Magenta 255,0,255 Cyan 0,255,255 Purple 128,0,128 Lime 0,255,0 Yellow 255,255,0 Maroon 128,0,0 Orange 255,165,0 White 255,255,255 Red 255,0,0 Gray 128,128,128 Brown 165,42,42 Black 0,0,0