Method of detecting the cleanliness of a lens using differential flat field correction of pupil incidence
US11268880B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 2021 |
| Grant date | Mar 8, 2022 |
| Priority date | — |
| Expiry date | Sep 24, 2041 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30168
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for detecting lens cleanliness of a lens in a flat-field optical path, the flat-field optical path includes a light source, the lens, a camera, the light source is a narrow-band multispectral uniform surface light source, the camera's light-sensitive surface is disposed perpendicular to an optical axis of the lens and in the light position of the lens and a pupil interposed between the lens and the light source, the method including collecting the bright-field image data and dark-field image data for a plurality of pupil aperture sizes through the lens; for each pixel, performing a pupil differential flat field correction to yield a plurality of PiPj pupil differentials; and displaying the pupil differentials in the form of a plurality of images to show uniformity of each image, wherein a non-uniform area on each image is determined to have been caused by an impurity of the lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.