Method and apparatus for three-dimensional imaging using laser illumination interferometry
US5926277A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 1998 |
| Grant date | Jul 20, 1999 |
| Priority date | — |
| Expiry date | Nov 25, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H2222/13
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method for determining a range dimension of an object utilizing multiple wavelength interferometry to form an image of the object includes developing a discernible two-dimensional image from an interference pattern at selected points for each of a number of wavelengths, collecting complex values from the interference pattern and developing a phase value from the complex value, and determining a phase correction vector based on a difference between measured phase values and an ideal phase value associated with one or more reference points. The phase correction vector is used to correct each of the selected points. A one-dimensional Fourier transform is performed on the corrected values to yield a range profile for each selected point. A peak value is then determined from the range profile to determine the range dimension. The peak value may be determined based on a simple maximum, oversampling in selected areas prior to performing the Fourier transform, or using curve-fitting techniques. The phase correction vector minimizes phase errors due to various causes such as insufficient knowledge of the laser frequencies, or which occur when optical path lengths of the object and referen…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.