Multi-resolution image scanner
US5267335A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 17, 1992 |
| Grant date | Nov 30, 1993 |
| Priority date | — |
| Expiry date | Jan 17, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/702
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image scanner is provided that receives light reflected from a same position on a document by first, second, and third one-dimensional image sensors arranged in parallel. The second image sensor is a high-resolution image sensor comprising a plurality of photocells, which is disposed between and in a spaced-apart relationship with the first and third one-dimensional image sensors which are each low-resolution image sensors comprising photocells which are larger in size than the photocells of the second one-dimensional image sensor. Electrical image output signals from the first and third low-resolution image sensors are added, and any high-frequency components in the added signal are removed by a low-pass filter for producing signal data relating to the mean brightness of the region around a pixel of interest. The difference between the mean brightness and the brightness of the pixel of interest, as outputted by the second high-resolution image sensor, is then derived to produce an output signal in which points to where the brightness changes in the image are emphasized. Subsequent processing enables textual and other information of interest in the document to be extracted from …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.