Modulation transfer function test compensation for test pattern duty cycle
US5959726A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1997 |
| Grant date | Sep 28, 1999 |
| Priority date | — |
| Expiry date | Jul 25, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M11/0292
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Improving accuracy of frequency response measurements of linear systems using modulation transfer function test compensation. An optical imaging system illuminates and images an input test pattern. A processor measures a modulation transfer function. The processor determines a compensating factor for error in the input test pattern duty cycle. The driving function for the measurement is a test pattern having a periodic waveform approximating a square wave with an error in duty cycle. A windowed fast fourier transform on a greyscale image of the test pattern generates odd harmonics. Adjusting amplitude values of the odd harmonics corrects for the error in resolution target duty cycle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.