Phased Illumination for Reflection-Free Document Imaging
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Solution Overview
Problem
Imaging devices face challenges in capturing high-resolution digital images of documents due to reflection artifacts caused by improperly positioned illumination sources, which can lead to non-uniform illumination and increased complexity and cost.
Innovation Solution
The method involves capturing a first digital image using illumination from one angle and a second digital image using illumination from a different angle, then combining these images to eliminate reflection artifacts, while positioning illumination sources outside the image sensor's field of view to prevent direct reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If illumination sources are positioned to minimize reflection artifacts, then image quality is improved, but uniform illumination across the target bed becomes difficult to achieve
Solution Approach 1:
The illumination function is segmented into multiple independent illumination sources positioned at different locations and angles. Each source illuminates a specific region, and their combined effect provides uniform illumination across the entire target bed while minimizing reflection artifacts through strategic angular positioning.
Solution Approach 2:
Different regions of the target bed receive illumination from sources positioned to optimize local illumination quality. Each illumination source is positioned to provide optimal illumination for its specific region while minimizing local reflections, and the combination of these localized optimizations achieves both uniform illumination and artifact reduction.
2Area of stationary object
If a large field of view image sensor is used to capture the entire document, then the device size is reduced, but reflection artifacts increase due to illumination source positioning constraints
Solution Approach 1:
The solution moves from a two-dimensional positioning problem to a three-dimensional solution by positioning illumination sources above and at angles to the target bed. This vertical and angular dimension allows sources to be placed outside the image sensor's field of view while still providing effective illumination, thereby eliminating reflections without compromising the large field of view capability.
Solution Approach 2:
The illumination sources act as intermediaries positioned strategically between the light source and the document. By placing these sources outside the field of view at specific angles, they provide necessary illumination without becoming visible in the captured image, thus eliminating reflection artifacts while maintaining the large field of view advantage.
3Illumination intensity
If multiple illumination sources are added to provide uniform illumination, then illumination quality is improved, but device complexity and cost increase
Solution Approach 1:
The illumination sources serve multiple functions simultaneously: they provide uniform illumination across the target bed, they are positioned to minimize reflection artifacts, and they are arranged to be outside the image sensor's field of view. This multi-functionality eliminates the need for additional separate systems for each function, thereby reducing overall device complexity despite using multiple sources.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in a composite digital image free of reflection artifacts, providing uniform illumination and reducing the complexity and cost of the imaging device by minimizing the need for intricate mechanisms and diffusers.
Implementation Method 1
capturing a first digital image of the document using illumination from a first illumination angle; capturing a second digital image of the document using illumination from a second illumination angle
Data Source
AI summary
Imaging devices and methods that permit the capture of digital images of an original document sequentially illuminated by a plurality of light sources. In one aspect, a first digital image is captured using illumination from a first illumination angle, a second digital image is captured using illumination from a second illumination angle, and the first and second digital images are combined to obtain a composite digital image of the document. The obtained composite digital image is free of reflection artifacts corresponding to the first and second illumination angles.