Image Reading Device Halation Prevention via Sequential Lighting
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Solution Overview
Problem
Conventional image reading devices require complex calculations and significant processing time to correct brightness issues and prevent halation when reading glossy documents, making them inefficient.
Innovation Solution
An image reading device with a shooting unit, light source unit, and controller that sequentially irradiates a bound document from opposing positions, allowing the shooting unit to capture images from different regions and combine them to generate a halation-free image, using a light source unit composed of multiple illumination blocks to minimize external influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional image reading devices use single-direction lighting to read glossy documents, then the device structure is simple, but halation occurs and brightness correction requires complicated calculation and much processing time
Solution Approach 1:
The patent divides the lighting into multiple segments (first lighting from above, second lighting from oblique direction) to separately capture different reflection components. This segmentation allows the system to acquire both specular and diffuse reflection information without requiring complex post-processing calculations, thus improving processing speed while maintaining manageable device complexity
Solution Approach 2:
The patent performs preliminary action by capturing both specular and diffuse reflection images simultaneously through multiple lighting sources before any calculation is needed. The arithmetic device then simply combines these pre-acquired images, avoiding the need for complex brightness correction calculations during processing, thereby significantly improving productivity
2Manufacturing precision
If conventional image reading devices illuminate the entire document surface uniformly, then the illumination system is simple, but reflection portions become too bright and require complicated brightness correction
Solution Approach 1:
The patent applies local quality by using oblique lighting (second lighting) that selectively illuminates specific regions of the document at different angles. This creates localized illumination patterns that reduce overexposure in reflection portions while maintaining adequate brightness in text areas, improving image quality without requiring complex brightness correction calculations
3Manufacturing precision
If the shooting unit captures the entire document in one shot, then the operation is simple, but halation in reflection portions degrades image quality
Solution Approach 1:
The patent uses periodic action by sequentially activating different lighting sources (first lighting from above, then second lighting from oblique direction) to capture multiple images. This periodic illumination pattern allows the system to acquire both specular and diffuse reflection information separately, enabling halation-free image quality while maintaining simple operation through automated sequential lighting control
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
Enables efficient image reading while preventing halation without the need for complicated calculations, reducing processing time and memory requirements.
Implementation Method 1
when the light source unit irradiates the document with light from the first irradiation position and the light is regularly reflected by the document at the first irradiation position side
Data Source
AI summary
An image reading device includes a shooting unit, a light source unit, a shooting controller, and a combining unit. The light source unit sequentially irradiates the bound document with light from first and second irradiation positions opposing each other with respect to a first straight line orthogonal to a direction of a binding portion of the document. The shooting controller controls the shooting unit to shoot a first region positioned at the second irradiation position side on the document when the light source unit irradiates the document with light from the first irradiation position, and controls the shooting unit to shoot a second region containing a region other than the first region on the document when the light source unit irradiates the document with light from the second irradiation position. The combining unit combines a shot image of the first region and a shot image of the second region.