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Proceedings Paper

Effect of image size and contrast on the recognition of insects in radiograms
Author(s): Thomas F. Schatzki; Pamela M. Keagy
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Paper Abstract

Radiograms of individual wheat kernels some of which contained immature insects (weevils moths or borers) were captured using microscopy into a 512x512x8 frame buffer 16. 4 pm/pixel. The resulting image was reduced repeatedly to half-size to produce collages containing 4 16 64 and 256 reduced images. Half the collages contained one and half no insect. Subjects were shown sets of 500 images on a 13 " monitor and were asked to determine whether an insect was present. Since hidden insects are typically characterized by a light insect inside a dark ring (the hole) inside a light kernel we measured the size of the recognizable region as the length (major diameter) and width of the hole in pixels in the reduced image. Contrast was represented as the square root of the variance of the pixel intensity along length or width. We find that recognition can be predicted to 80-90 by length alone contrast or width add little. The length for 50 recognition amounts to 12. 20. 6 22. 10. 7 and 19. 80. 6 pixels for weevils moths and borers resp. It is suggested that insect recognition depends on recognizing as yet unknown image features which are lost when images are reduced beyond this size. 1."

Paper Details

Date Published: 1 February 1991
PDF: 7 pages
Proc. SPIE 1379, Optics in Agriculture, (1 February 1991); doi: 10.1117/12.25089
Show Author Affiliations
Thomas F. Schatzki, U.S. Dept. of Agriculture (United States)
Pamela M. Keagy, U.S. Dept. of Agriculture (United States)


Published in SPIE Proceedings Vol. 1379:
Optics in Agriculture
James A. DeShazer; George E. Meyer, Editor(s)

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