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United States Department of Agriculture

Agricultural Research Service

Title: Analysis of Insect and Plant Colors in Digital Images Using Java Software on the Internet

Author
item Byers, John

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 29, 2006
Publication Date: August 1, 2006
Citation: Byers, J.A. 2006. Analysis of insect and plant colors in digital images using java software on the internet. Annals of the Entomological Society of America 99(5): 865-874.

Interpretive Summary: Description of colors of insects and plants in ecological research is often subjective and imprecise. A quantitative, statistical, and standardized method for describing such colors by software analysis of digital images would be useful, especially if readily available. I have made an Internet web page with JavaScript that runs a Java applet for loading an image and analyzing the red, green, and blue (RGB) intensity components of the pixels in any rectangular area to obtain a mean, standard deviation (SD), coefficient of variation (CV), and percentage of each of the three color components. Thus, a colored area in an image can be depicted objectively in publications as R +/- SD, G +/- SD, and B +/- SD, or percentages thereof, and allow the mean color to be reproduced elsewhere by paint programs. The software makes two figures for each analysis, a quasi-spectral wavelength-intensity graph of the three component colors as Gaussian curves and their scaled overlapping summation, and a bar graph with SD lines. The software was used to analyze colors of flowers and leaves of two species of cotton (white and red varieties of upland, Gossypium hirsutum L., and Pima, G. barbadense L.), western tarnished plant bug (Lygus hesperus Knight), yellow plastic sheeting used in insect traps, and eight other insect species (Adelges cooleyi, Chrysoperla carnea, Ochlodes venatus, Thanasimus formicarius, Formica aquilonia, Acanthocinus aedilis, Cicindela campestris, and Ips paraconfusus). Three two-dimensional color-space diagrams (hexagon, 2D-cube, and ternary percentages) are described and used to plot colors obtained from the analyses. Statistical tests are presented that compare whether two groups of color-space points in three dimensions are significantly separated. Differences in color vision in insects, vertebrates and humans are discussed.

Technical Abstract: Description of colors of insects and plants in ecological research is often subjective and imprecise. A quantitative, statistical, and standardized method for describing such colors by software analysis of digital images would be useful, especially if readily available. I have made an Internet web page with JavaScript that runs a Java applet for loading an image and analyzing the red, green, and blue (RGB) intensity components of the pixels in any rectangular area to obtain a mean, standard deviation (SD), coefficient of variation (CV), and percentage of each of the three color components. Thus, a colored area in an image can be depicted objectively in publications as R +/- SD, G +/- SD, and B +/- SD, or percentages thereof, and allow the mean color to be reproduced elsewhere by paint programs. The software makes two figures for each analysis, a quasi-spectral wavelength-intensity graph of the three component colors as Gaussian curves and their scaled overlapping summation, and a bar graph with SD lines. The software was used to analyze colors of flowers and leaves of two species of cotton (white and red varieties of upland, Gossypium hirsutum L., and Pima, G. barbadense L.), western tarnished plant bug (Lygus hesperus Knight), yellow plastic sheeting used in insect traps, and eight other insect species (Adelges cooleyi, Chrysoperla carnea, Ochlodes venatus, Thanasimus formicarius, Formica aquilonia, Acanthocinus aedilis, Cicindela campestris, and Ips paraconfusus). Three two-dimensional color-space diagrams (hexagon, 2D-cube, and ternary percentages) are described and used to plot colors obtained from the analyses. Statistical tests are presented that compare whether two groups of color-space points in three dimensions are significantly separated. Differences in color vision in insects, vertebrates and humans are discussed.

Last Modified: 4/18/2014
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