Method for detecting velocity or displacement of an object over a surface by analyzing images of the surface
US6697501B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 2000 |
| Grant date | Feb 24, 2004 |
| Priority date | — |
| Expiry date | May 7, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T7/262
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
There is described a method for detecting relative displacement between an object such as a slow moving vehicle and an illuminated surface which is normally the ground surface illuminated by an infrared light source so as to provide an output indicating the displacement or a velocity calculated from the displacement. The method includes providing an array of CCD or similar elements each arranged to receive light from a portion of a field of view and to provide an output responsive thereto. The method involves selection of a reference image and repeatedly comparing the reference image of the surface with each successive image by calculating the convolution integral of the signals using a fast fourier transform to obtain a probable displacement value. The reference image is maintained as long as possible until a “Q” factor falls below an acceptable minimum, or until a predetermined time elapses or until a predetermined displacement is measured. The displacement values obtained from the comparisons can be filtered by discarding some values if they are outside an expected range of probable values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.