Browse Prior Art Database

Displaying Reliability of Contour Surface

IP.com Disclosure Number: IPCOM000121273D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 35K

Publishing Venue

IBM

Related People

Halbert, A: AUTHOR [+2]

Abstract

In graphics display processing when an equicontour field surface is computed, the surface is accurately placed where the field is rapidly changing, but not so clearly defined where the field is fairly static. This article helps the user of a visualisation system see how well defined different parts of a contour surface are by the use of the rate of change of a field to color a display of its contour.

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Displaying Reliability of Contour Surface

      In graphics display processing when an equicontour field
surface is computed, the surface is accurately placed where the field
is rapidly changing, but not so clearly defined where the field is
fairly static.  This article helps the user of a visualisation system
see how well defined different parts of a contour surface are by the
use of the rate of change of a field to color a display of its
contour.

      A rendered image of a contoured scalar field as employed in the
Winchester Solid Modeller (WINSOM) is a powerful tool for visualizing
such a field.  The lighting and surface effects allow a good three-
dimensional impression to be made from a two-dimensional picture.  In
particular, they indicate the direction of the gradient of the field
at points on the contour surface.

      Also of interest is the rate with which the field is changing,
that is the absolute value of the gradient.  Where this value is
high, the field is changing rapidly, and the contour surface is well
defined.  Where this value is low, the field is fairly static, and no
reliable inference can be drawn from the exact position or direction
of the contoured surface.

      An improvement will be effected by the use of the WINSOM and
WINVIS90 COLOURBY, based on the field ABS(GRAD). High values will,
for example, be colored red (well-defined surface), and low values
green or white (ill-defined surface).  The intermediate values may
use...