Arrangement for rapid depth measurement using lens focusing
US4640620A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 29, 1983 |
| Grant date | Feb 3, 1987 |
| Priority date | — |
| Expiry date | Dec 29, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/25
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A pattern of light is projected upon a surface to be measured which may be devoid of surface detail. A sharply focused image of the surface provides distance discrimination. Although the projected pattern may be separate from the imaging optics, a common optics path removes distortion, provides maximum sensitivity and eliminates processing for misalignment between projector and imager. Parallel detection of regions within the image receiving light intensities above a threshold enables rapid availability of measurements. Optical cross-correlation and Fourier transform processing methods may be employed to enhance image processing with no processing delay. Three-dimensional co-ordinate measurements relative to the sensor are reported for all in-focus regions of the image. Refocusing the lens provides depth coverage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.