Image scanner having improved pixel convolution operation
US5272545A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 17, 1992 |
| Grant date | Dec 21, 1993 |
| Priority date | — |
| Expiry date | Jan 17, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/409
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image scanner that can extract the information of interest from a document at high speed, using a relatively small-scale circuit arrangement that provides an image processing performance equal to that obtained by applying convolution to a larger number of pixels. Light reflecting from the document is converted to electrical image signals by a one-dimensional image sensor. After these image signals have been digitized by an A/D converter, they are input to an adder. A portion of the digitized signals is input to a rounding circuit in which the average intensity of a pixel unit, each comprised of a prescribed number of pixel groups, is calculated. These units are treated as pseudo pixels on which convolution is performed by a convolution integrator. A subtracter is then used to obtain the difference between signals input from the A/D converter and signals output by the convolution integrator. This is then used to obtain the difference between the intensity of the pixel of interest and the average intensity of the prescribed number of surrounding pixels to effectively distinguish alphanumeric characters and other such information, from the background.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.