Light scanner web profile measurement apparatus and method
US5073712A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 11, 1991 |
| Grant date | Dec 17, 1991 |
| Priority date | — |
| Expiry date | Apr 11, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/933
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus provide for determining properties of a web of traveling sheet material by scanning light including at least selected wavelengths such as IR and/or visible wavelengths across the web of material and also across at least two calibration samples. The signals generated in response to the scanning of the calibration samples is used to calibrate the scanning operation preferably on every scan. By providing at least two calibration samples, better estimates of average calibration parameters can be made and detection of a faulty calibration sample is facilitated. The calibration samples preferably are protected by mounting them within a scanner housing in relatively close proximity to a scanning beam generator. In addition, at least two compensation samples are supported substantially adjacent the moving web of material and preferably at least one compensation sample is positioned on each side of the web. By providing two compensation samples, fault conditions or fouling of either one of the compensation samples can be readily detected and also be used to better generate an average compensation signal. Compensation is particularly advantageous in accounting for ambi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.