Method of measuring distance using ultrasonic waves
US5197019A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 1990 |
| Grant date | Mar 23, 1993 |
| Priority date | — |
| Expiry date | Jul 19, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B17/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for measuring the distance e separating two faces (3, 4) of an object (1) employs the ultrasonic wave diffused back by said faces and received by a sensor (6). Following digitalization (11), the temporal signal is transformed (12) into a frequency spectrum. The modulus of the frequency spectrum is established (13) then the logarithmic derivative thereof is calculated (15) from whence there results a useful signal including a periodic signal onto which a linear signal is superposed. Following suppression (14, 16) of the linear signal the useful signal is applied (17) to a frequency window in order to eliminate the noise therefrom. The signal thus obtained is inversely transformed (18) to obtain a signal the amplitude of which is a function of the time and the envelope of this latter signal is determined (19). After having determined the temporal spread .DELTA.t separating the time origin from the envelope peak showing the greatest amplitude, the distance e is calculated from the relation e=c.multidot..DELTA.t/2, c representing the propagation velocity of the ultrasonic wave. The method may be employed for the non-invasive measurement of the thickness or diameter of an arter…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.