Freehand image scanning device which compensates for non-linear color movement

DETAILED DESCRIPTION A scanning device and method for forming a scanned electronic image include using navigation information that is acquired along with image data, and then rectifying the image data based upon the navigation and image information.
In the preferred embodiment, the navigation information is acquired by means of at least one navigation sensor that detects inherent structure-related properties of an original being scanned.
Movement of an image sensor along the original may be tracked by monitoring variations of the inherent structure-related properties as the image sensor is moved relative to the original.
Preferably, the inherent structure-related properties that are monitored are inherent structural features, such as paper fibers, or other constituents of the original.
Navigation may also speckle-based, wherein movement of the image sensor along the original is tracked by monitoring variations of speckle patterns produced using coherent illumination for acquiring the navigation information.
"Inherent structure-related properties" are defined herein as properties of the original that are attributable to factors that are independent of forming image data and/or of systematic registration data on the original.
The navigation information may be formed by generating a position signal that is responsive to detection of inherent structure-related properties, such as a position signal of speckle information or a position signal that permits tracking of individual inherent structural features.
"Inherent structural features" are defined herein as those features of an original that are characteristic of processes of forming the original and are independent of forming image data and/or systematic registration data on the original.
For example, if the original recorded media is a paper product, the inherent structural features of interest may be paper fibers.
As another example, navigation of the image sensor across a glossy original or an overhead transparency film may be determined by tracking surface texture variations that affect specular fields