HUE ANGLE DETERMINATIONS AND STATISTICAL ANALYSIS FOR MULTIQUADRANT HUNTER L,a,b DATA

Abstract

ABSTRACT For purposes of data analysis and data interpretation, it is important to have uniform representation of hue derived from the Hunter L, a, b color space. Using the standard calculation for hue [Arc tan (b/a)], positive signed results are generated for the first quadrant [+a, +b] only. The other quadrants should be handled so that a 360° representation is accommodated and results are expressed as positive signed numbers. Second quadrant [‐a, +b] and third quadrant [−a, −b] calculations should be: hue = 180+Arc tan(b/a). Fourth quadrant [+a, −b] calculations should be: hue = 360+ Arc tan(b/a). Furthermore when planning statistical analysis of data which transverse the IV and I quadrant, tranformations of the data will continue increasing in hue angle from 361° on up as high as appropriate. A spreadsheet macro for achieving these results can be easily derived.