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 ∆E 94 = [(∆L/k L S L ) 2 +(∆C/k C S C ) 2 +(∆H/k H S H ) 2 ] 1/2  DE00 ∆E 94 =[(∆L’/k L S L ) 2 +(∆C’/k C S C ) 2 +(∆H’/k H S H ) 2 +R T (∆C’/k C S C )(∆H’/k H S H )] 1/2  DEopti DEopti=[C1+C2∆ L 2 + C3∆a 2 +C4∆b 2 +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 = log e [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!