Method for measurement of displacement of moving body by use of target mark and apparatus therefor
US4297725A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Aug 21, 1979 |
| Grant date | Oct 27, 1981 |
| Priority date | — |
| Expiry date | Aug 21, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/002
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed herein are a method for the measurement of physical displacement, including the angular displacement, of a body in motion and an apparatus for use in the method, which method comprises placing on the body a target mark divided by two perpendicularly intersecting lines into four areas which are shaded alternately bright and dark, taking the image of the target mark with an image pickup tube capable of random deflection by having a carrier for circular sweep superposed on a deflection voltage and thereby producing video signals, subjecting the video signals to synchronous rectification with the carrier and a sub-carrier possessing a frequency two times the frequency of the carrier for thereby obtaining mean values, calculating the value of deviation between the centers of the target mark and the circular sweep on the basis of the mean values and feeding the value of deviation back to the image pickup tube to cause the centers of the target mark and the circular sweep to coincide with each other, whereby the positional displacement and the angular displacement of the target mark on the body is measured on a real time basis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.