Evaluating New Color Sensor Technology-the Nix Pro-for Horticulture Applications

Color is a critical component of horticulture, whether it is on fruits at a grocery store or part of a description on a newly discovered flowering tree. The Royal Horticultural Society developed a paint chip-based “Colour Chart” that has been used by horticulturists as a standard color reference for decades. This system relies on the manual assessment of color matching and is highly subjective, as people do not perceive color in the same way. This disqualifies a manual color chart system as a viable method for the accurate identification of color in plants. The Konica Minolta Chromo Meters are used as objective color sensor platforms and gauge colors numerically for a multitude of color space models. The Konica Minolta Chromo Meters, although valuable, are expensive, cumbersome, and can be difficult for use in field applications. A new hand-held device, the Nix Pro Color Sensor, measures color of any surface and provides color data to smartphones or tablets. A Nix Pro Color Sensor was obtained for a comparison study with the Konica Minolta CR-200, CR-300, and CR-400 Chromo Meters. The Nix Pro is lightweight and costs considerably less than the latest Konica Minolta Chromo Meter (CR-400). For this project, color values were recorded using the L*a*b* color space created by the Commission International de I’Eclairage (CIE) in 1976. Color data were collected on seven different colored fruits and vegetables (yellow lemon, green apple, blueberry, red chili pepper, brown kiwi, peach blush, and peach yellow background). Statistical analysis of the color data indicated that the internal consistency, measured using standard deviation, was excellent for the Nix Pro. The Konica Minolta CR-200 showed the least consistency overall, with the b* scale revealing consistently greater standard deviations among fruit samples. The relationship between the same scale (L*, a*, or b*) as measured by the CR-400 and the Nix Pro differed from color to color, and there did not appear to be a consistent “bias” across all colors. The Nix Pro shows promise as a highly efficient and accurate research tool due to its low cost, small size, and consistency.