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Biomedical subjects

N B Mitchell

Publications and source records attributed to N B Mitchell.

2 recordsLinked to original sources

A simple method for hardware and software evaluation.

Subjective data are often the only data available for making decisions and choices in both hardware and software development. These data are therefore both important and valuable. Their importance is such that it is necessary to elicit subjective data from a variety of sources and in a manner that is relatively unbiased. A method which requires participants to compare all criteria and all proposed concepts by pairs provides a non-statistical mechanism for collecting data from a broad base of expertise, for giving appropriate weight to all input, and for reducing personal bias. These characteristics make a comparison of all pairs a useful tool for hardware and software evaluation when decisions and choices must be made. The efficacy of the method was recently demonstrated in the selection of a restraint-attachment device for Space Station Freedom.

Journal Article↗

Distance perception in photographic displays of natural settings.

Distance perception of depicted objects was examined as a function of photographic perspective. 24 subjects viewed slides of outdoor scenes and directly estimated the distances to specified objects. Perspective was manipulated by photographing each scene with lenses of four different focal lengths: 48 mm, 28 mm, 24 mm, and 17 mm. Distance perception along the pictorial depth plane (z-axis) was systematically transformed by changing the photographic perspective: the shorter the focal length of the camera lens, the greater the perceived distance. Perceived distance between objects along the lateral plane (x-axis) was unaffected by changes in lens focal length.

Cues↗