Correcting tilt-induced cyclic variations in signals from radially arrayed spectrophotometer sensors
US8255181B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 12, 2009 |
| Grant date | Aug 28, 2012 |
| Priority date | — |
| Expiry date | Apr 11, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J3/524
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A correction algorithm may be applied for correcting misalignment of a radially-aligned array of sensors. Due to the tilt, signals from sensors that are further away from the media, may become slightly attenuated, while signals from sensors that are closer to the media are slightly increased. The error appears periodic and largely sinusoidal in nature around the array given the circular nature of the array of sensor elements. The algorithm determines the magnitude and phase of a sinusoidal function that best fits the wavelength data. In one embodiment, a discrete Fourier transform may be performed at the ‘frequency’ equivalent to one period around the array to determine the magnitude and phase estimate thereof. Then, a sinusoidal correction function may be generated using the magnitude and the phase in order to correct the reflectance data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.