Browse Prior Art Database

Method of Determining Line or Edge Orientation

IP.com Disclosure Number: IPCOM000111343D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Camp, WO: AUTHOR

Abstract

Disclosed is a method for determining the orientation of a line or edge within an image projected onto an array of photosensors.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 75% of the total text.

Method of Determining Line or Edge Orientation

      Disclosed is a method for determining the orientation of a line
or edge within an image projected onto an array of photosensors.

      Prior state-of-the-art has used convolution templates to detect
line and edge orientation.  The problem with this method is that a
threshold must exist for membership in the classes representing
orientation.  This means that the result is sensitive to the absolute
values of the input image.  Furthermore, if many line widths are
encountered, then many templates will be needed.

      This invention uses an array of photosensors (for instance,
8-by-8) that responds to an image projected on it, by generating
analog outputs corresponding to the light intensity at each detector.
These currents are reproduced in current mirrors at each site;  one
for each line orientation to be detected.  Currents are summed from
these current mirrors along multiple, elongated paths in each of the
desired orientations.  Thus, each orientation might have 8 sums from
8 wires collecting currents from detectors located along each of 8
lines in that orientation.  These 8 sums connect to a resolving
network that detects a difference above a threshold, between any of
the 8 sums.  This happens separately for all orientations.

      The resolving network consists of multiple circuits that yield
zero output current when inputs to it are the same within a threshold
value, and yield an output curre...