Non-contact determination of the position of a rectilinear feature of an article
US5033096A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 22, 1988 |
| Grant date | Jul 16, 1991 |
| Priority date | — |
| Expiry date | Apr 22, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/046
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A high resolution CCD video camera (6) is positioned and aligned with respect to an illuminated article (7) so that a straight edge of the article, or a straight line junction between a bright zone and a dark zone of its surface, crosses the field of view of the camera in a direction substantially parallel to the rows of the camera's orthogonal array of rows and columns of light responsive elements, to divide that field of view into bright and dark zones. A frame store and digitizer (9) converts the individual signals generated by the elements into digital grey values. The grey values derived from the elements of each row are summed by a computer (10) to produce a linear array of summation values positionally related to the respective columns, and the computer then determines the position of the edge or junction to a sub-column spacing accuracy by determining the mean value of two of the summation values selected respectively from a row receiving energy from the bright zone and one receiving energy from the dark zone and establishing a position in the array for the mean value, and thus for the feature, by interpolating the mean value between the two summation values immediately abo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.