SOFTWARE FOR IMAGE SEGMENTATION AND ANALYSIS
IN PATHOLOGY (ISAP).
EDGE DETECTION MENU.
Copyright © 1994 G. William Moore, Geoffrey W. Moore,
Jules J. Berman, Lawrence A. Brown.
http://www.medparse.com/isapedge.htm
U. S. Government Work, presented at the 1994 meeting
of the American Society of Clinical Pathology, Washington, DC.
Moore GW, Berman JJ, Moore GW, Brown LA.
Software for Image Segmentation and Analysis in Pathology (ISAP)
Am J Clin Pathol 102:538-539, 1994.
1. ISAP EDGE DETECTION MENU.
EDGE menu: There are three submenus: METHOD; THRESHOLD; WINDOW SIZE.
METHOD SUBMENU. The Method Submenu sets the edge-detection method.
Two methods are offered: SOLID-FILL and RADIAL. In each method,
the system classifies all points (pixels) in the SELECT-BLOCK
as INSIDE, EDGE, or OUTSIDE. All parameters for the particle
(area, average density, perimeter, etc.) are calculated
from this classification.
In the SOLID-FILL METHOD, the system begins by designating
the center point as INSIDE. At each INSIDE point, the system
examines at four contiguous points: left, right, up, and down.
Each of these candidate points is scored and tested against
a THRESHOLD level (from 0 to 255, default=90). If the average score
is above the current THRESHOLD, then the candidate point is INSIDE.
The average score is the average of all points in a WINDOW, centered
at the candidate point. The WINDOW may be 3x3 points, 5x5 points,
7x7 points, or 9x9 points. The process continues to exhaustion.
In the RADIAL METHOD, the system begins by designating
the center point as INSIDE. A vector is projected at three degree
intervals, from 0 to 360. At each angle, the system steps from the
center to the first point which scores above the current THRESHOLD.
THRESHOLD submenu:
The THRESHOLD submenu sets the threshold at which the EDGE
of a particle is detected. Values range from 0 to 255, default=90.
WINDOW submenu:
The WINDOW submenu sets the window-size for calculating the
average score in the edge detection methods. The average score
for a given point is the average of all points in a WINDOW,
centered at that point. The WINDOW may be 3x3 points, 5x5 points,
7x7 points, or 9x9 points.
Last Updated: January 23, 2003, by G. William Moore, MD, PhD.