Browse Prior Art Database

Fine Position Tracking Method

IP.com Disclosure Number: IPCOM000099462D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Inena, Y: AUTHOR [+2]

Abstract

Disclosed is a highly accurate method for measuring the position of an object from the datum point concerning pin position measurement in a print head assembly.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 64% of the total text.

Fine Position Tracking Method

       Disclosed is a highly accurate method for measuring the
position of an object from the datum point concerning pin position
measurement in a print head assembly.

      High accuracy is provided by the combination of a scanner's
mechanical position measurement with a linear encoder and pin
position measurement with image processing. Fig. 1 shows the
configuration of the system.  The object is set on the X-Y table
which locates one of the pins in the print head assembly into the
image field to acquire image data of the pin by CCD camera. The
movement of the X-Y table is controlled by the X-Y table controller,
which is controlled by a processor through a digital interface DI/DO.
 The absolute position of the X-Y table is measured using accurate
linear encoders which are installed to each axis of the X-Y table in
parallel with pin location measurement in the image by image
processor.  Two position data are merged in the processor to
calculate the pin's position deviation from datum position.
According to this method, position measurement accuracy exceeds the
X-Y table's mechanical accuracy and resolution of the image
processor.

      The scanner, X-Y table, carries the object to the predetermined
position, and the absolute position of the X-Y table (TBL_X,TBL_Y) is
measured by linear encoder to transfer it to the processor via
asynchronous communication line.  An image signal which is obtained
by the CCD camera is digitized...