Method for determining the profile of a bound document with structured light
US5835241A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 30, 1996 |
| Grant date | Nov 10, 1998 |
| Priority date | — |
| Expiry date | May 30, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/04794
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An overhead scanning system records pages from bound documents in an upright and open condition. A light stripe is projected onto each page of the bound document to measure the non-planar deformations of each page. The scanning system records a first image with the light stripe and a second image without the light stripe. After identifying a set of pixels representing the light stripe in the first image, the set of pixels is smoothed to minimize large transitions between scan lines. Subsequently, a crease is identified in the set of pixels that represents the spine of the bound document. The pixels forming the crease are replaced with pixels that are defined using a parametric model that approximates the spine region of a bound document. This substitution insures that the spine region of a bound document is accurately depicted before determining a page shape transform with the identified set of pixels representing defining the projected light stripe. An image correction system de-warps the second image using the page shape transform and a perspective transform to correct distortion due to the pages of the bound document being curved relative to the support plane of the system. The …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.