The effects of media color and laser wavelength on bar code symbol contrast
Abstract
The purpose of this study was to investigate the impact of media color and laser wavelength as they relate to bar code symbol contrast. The research employed a balanced 2 x 2 x 6 factorial experiment design. A random sample of 216 specimens was drawn from a population of 910 colors from the 1998 Pantone Color Formula Guide and assigned to one of 24 hue-saturation-wavelength cells. Hue was defined based on the CIE 1964 chromaticity diagram and standard illuminant D65. The chromaticity diagram was divided into six regions: blue, green, yellow, orange, red, and purple. The chromaticity coordinates (Yxy) of each Pantone specimen were transformed such that the coordinates of D65 was the origin. Lines extended from D65 to the spectral locus defined hue regions. Specimens whose transformed coordinates fell within a particular region were assigned that hue. Next, all specimens were classified as highly saturated if their white content was less than 50%. Otherwise, their saturation was defined as low. Finally, specimens from each hue-saturation group were randomly assigned to one of two wavelength levels: 633 or 670 rim. The measurement apparatus was constructed according the geometry defined in the ANSI Bar Code Print Quality Guideline—X3.182-1990. Data were collected following a random cell-order pattern to minimize the effect of any systematic, investigator-induced error. An analysis of variance was performed to test seven hypotheses: the main effects for each of the three independent variables and all possible interactions between them. The analysis indicated the ANOVA model of hue, saturation, and wavelength with all possible interactions was significant (p = .0001; R2 = 74.1) in explaining the variance in symbol contrast. Hue (p =.0001; R2 = 39.3) and saturation (p = .0001; R2 = 28.2) were significant independent variables. There was no significant difference detected between 633 nm and 670 nm wavelengths. The only significant interaction was between hue and saturation (p = .0001; R2 = 5.3). The effect of the interaction was relatively weak and indicated that when specimen hues were less saturated, the effect of hue on symbol contrast was diminished. Recommendations for future research are offered.
Degree
Ph.D.
Advisors
Russell, Purdue University.
Subject Area
Optics|Electrical engineering
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.