Proc. Application of Optical Instrumentation in Medicine XI, Gary D. Fullerton, ed., Proc. SPIE 419, pp. 60-67, 1983

Variations in task and the ideal observer

Kenneth M. Hanson
Los Alamos National Laboratory


In most previous studies involving the ideal observer, the task considered has been that of simple detection where it is assumed that there is complete a priori knowledge of the background and of the possible object's shape, amplitude, and position. It is shown that redefining the detection task to include the possibility of an unknown, slowly varying background reduces the importance of the low-frequency components in the image for the ideal observer. More complicated tasks than object detection are also considered, such as determination of an object's position and width and the resolution of two objects. These higher-order tasks further enhance the importance of the high-frequency information content of the image.

Keywords: ideal observer, detection task, shape determination, amplitude estimation, Rayleigh task, importance of high spatial frequencies

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