MAPPING OF AMPLITUDE ONTO CRT LUMINANCE IN FREQUENCY-TIME-INTENSITY DISPLAYS

Authors
  1. McFadden, S.M.
  2. Swanston, K.
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN)
Abstract
A common method of presenting passive sonar information on a CRT is the frequency-time-intensity (FTI) display. Detection of targets on an FTI display can be affected by the method used to map the original sonar input onto the visual display. The current study examined the problem of mapping the acoustic amplitude of the incoming sound onto CRT luminance. Detectability of a single target line was measured as a function of the number of quantization levels used to map amplitude onto CRT luminance (2, 4, 8, 16 or 256) and the marking density (percentage of the display set to other than background luminance). Marking density was varied by mapping all amplitude below a fixed cut-off point (either 3, 1, or O S.D. below the mean of the noise) on to the lowest quantization level. On average, detection performance improved more than 3dB as the number of quantization levels increased from two to eight. If amplitude was mapped onto fewer than sixteen quantization levels, the selection of a cut-off point was important.
Report Number
DCIEM-89-13B — Research Paper; Reprint
Date of publication
01 Jan 1988
Number of Pages
3
Reprinted from
Proc of the Human Factors Society Annual Meeting (30th)
DSTKIM No
93-04964
CANDIS No
135515
Format(s):
Hardcopy;Originator's fiche received by DSIS

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