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Browse Prior Art Database

Method for Detecting Center of Theta Table by Image Processing

IP.com Disclosure Number: IPCOM000119929D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Saitoh, F: AUTHOR

Abstract

Disclosed is a method for detecting the center of a theta table which is used to provide rotation in work positioning.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Method for Detecting Center of Theta Table by Image Processing

      Disclosed is a method for detecting the center of a theta
table which is used to provide rotation in work positioning.

      The method comprises the following steps:

      STEP 1:
Set on the theta table a work which has a visual reference point. The
table is monitored by a TV camera and a display.

      Step 2:
Rotate the theta table and detect addresses of some points P1 - P5
traced by the reference point.  The detected points P1 - P5 will be
on the same circle with its center positioned at the center of the
theta table.

      Step 3:
Set a window at a central area of the TV image.  The window must be
set to include the table center.

      Step 4:
Get distances L1 - L5 from a selected pixel in the window to each of
the detected points P1 - P5 and then calculate the difference between
the longest distance and the shortest one.

      Step 5:
Plot the difference value calculated in step 4 in a two-dimensional
memory array at a location corresponding to the pixel selected in
step 4.

      Step 6:
Repeat steps 4 and 5.

      Step 7:
Determine the minimum value and its location in the memory array. The
pixel corresponding to the location represents the center of the
theta table.