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

Abstract

Forpurposes of data analysis and data interpretation, it is important tohave 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. l2e 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, -bJ calculations should be: hue = I80+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, vanformations 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.

Características biométricas e físico-químicas do fruto, morfologia da semente e da plântula de Averrhoa carambola l. (oxalidaceae)

“…Quanto ao parâmetro b, que mede a variação do azul (-b) ao amarelo (+b), observou-se que a presença da cor amarela aumentou à medida que o estádio de maturação avançou do verde ao maduro. Portanto, considerando-se apenas o plano a-b no diagrama de Hunter (McLellan et al, 1995), verificou-se que a cor das carambolas classificadas como verdes e intermediárias encontra-se no quadrante II do diagrama, ou seja, entre verdes e amarelo-esverdeadas; a cor dos frutos classificados como maduros encontra-se no quadrante I, com predominância da cor alaranjada.…”

Peach Palm (Bactris gasipaes kunth) Characterization and the Potential of by-Products Flour Processing

“…C* (Chroma, color saturation) was obtained according Equation 2 (Giese, 2000) and H (hue angle) was calculated according to Equation 3 when positive results were generated for the first quadrant (+a*, +b*) and followed Equation 4 when negative values of a* and positive values of b* were obtained (second quadrant) (Mclellan et al, 1995).…”

Producción y evaluación funcional de un concentrado proteico de calamar gigante (Dosidicus gigas) obtenido mediante disolución alcalina Production and functional evaluation of a protein concentrate from giant squid (Dosidicus gigas) obtained by alkaline dissolution

“…Se registraron los para´metros L* (luminosidad), a* (matiz rojo-verde) y b* (matiz amarillo-azul), con los cuales se calculo´el a´ngulo de matiz utilizando la siguiente ecuacio´n: Angulo de matiz ¼ Arc Tan (b/a) (McLellan, Lind, & Kime, 1995); y para calcular el ı´ndice de blancura se utilizo´la siguiente ecuacio´n:…”