IDL GUI FOR OPTIMIZING COLOR TOLERANCE EQUATIONS

1. IDL GUI FOR OPTIMIZING COLOR TOLERANCE EQUATIONS Presented By: Rohit A. Patil Instructor: Rolando Raqueño

2. INTRODUCTION • Useful for making pass-fail decisions of batches in quality control • Typical Industrial practice included a ‘single observer’ making pass-fail judgments of batches. • This had many disadvantages: • Observer not a standard observer • ‘Acceptability’ Vs ‘Perceptibility’ • Observer’s tolerance increases

3. SOLUTION • Use of spectrophotometer • Advantages: • Judgments based only on ‘perceptibility’ • Savings in wages • Key requirement: • Optimum color tolerance equation

4. SELECTION OF A COLOR TOLERANCE EQUATION • Options available • DEab • CIE94 • CIEDE2000 • Derive a new equation (DEopti) • Good things about DE94 and DE00 • Use of parametric factors

5. THE EQUATIONS • DE94 ∆E94 = [(∆L/kLSL)2+(∆C/kCSC)2+(∆H/kHSH)2]1/2 • DE00 ∆E94 =[(∆L’/kLSL)2+(∆C’/kCSC)2+(∆H’/kHSH)2+RT(∆C’/kCSC)(∆H’/kHSH)]1/2 • DEopti DEopti=[C1+C2∆L2+C3∆a2+C4∆b2+C5∆a∆b+C6∆L∆a+C7∆L∆b]1/2

6. REQUIREMENTS FOR OPTIMIZATION • Pass-fail visual data around a color standard converted to an interval scale ∆V = loge[f/(1-f)] • ∆V will increase with increase in actual color difference • Color tolerance equation fitted to this data using multiple linear regression • Closeness of fit given by correlation coefficient

7. THE GUI • Divided into three widgets • Starting instruction widget • Widget for DE2000 • Widget for optimizing and comparing the equations

8. DE2000 WIDGET • Calculate DE00 for any number of samples around a single standard • Save the calculated data in a text file

9. COLOR TOLERANCE WIDGET • Includes import data buttons • Table widgets: • Giving coefficients of optimized equation • Giving l, c, h values for DE94 and DE00 • Giving correlation coefficients of the five equations • Slider widget: • Allow user to manipulate the coefficients of optimized equation

10. DATA USED • Pass-fail experiment carried out for Color Measurement Lab-I • Sixteen observers • Took two days to do the calculations

11. FUTURE ENHANCEMENTS • Tool for analyzing inter-observer variance • Add a tool for calculating instrumental wrong decisions

12. LETS LOOK AT THE DEMO! Thank you!