Method and apparatus for sensing the presence of a line of data from a document on a transparent surface
US5760412A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 14, 1996 |
| Grant date | Jun 2, 1998 |
| Priority date | — |
| Expiry date | Feb 14, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/00782
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Apparatus and a method for sensing the presence of a document on the transparent surface of an optical scanner involve moving a scanner optics carriage to a predetermined position beneath the transparent surface, reading a line of data, and if any of the data is on the "white" side of the gray-scale relative to a threshold, determining that a document is present in the scanner. Optionally, before determining whether a document is present, the apparatus and method may perform an initial threshold comparison to check for the presence of a dark background to ensure that an old document has been removed before the new document is read. The results of the document presence determination are used to generate a signal which is sent through a scanner interface to the host computer for use in automatically initiating a complete scan of a new document.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.