Image Reading Device Shading Correction for Variable Surface Diffusion
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Solution Overview
Problem
Existing image reading devices face challenges in performing shading correction efficiently across various materials with different diffusion characteristics of reflected light, such as cloth and glossy metal surfaces, as general shading correction methods are inadequate in coping with these variations.
Innovation Solution
An image reading device that controls multiple light sources to turn on specific LEDs, acquires diffusion states of reflected light both with and without the target, and generates dedicated shading correction data based on these states and general shading correction data to adapt to the target's specific diffusion characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If general shading correction data is used for all materials, then the device complexity is reduced and processing is simplified, but the shading correction accuracy deteriorates for materials with different diffusion characteristics
Solution Approach 1:
The patent segments the shading correction process into two distinct parts: general shading correction data (applicable to all materials) and dedicated shading correction data (specific to each material type). This segmentation allows the system to maintain simplicity for common cases while providing material-specific accuracy when needed, resolving the contradiction between processing simplicity and correction accuracy.
Solution Approach 2:
The patent changes the parameter of shading correction data by generating dedicated correction data specific to each material's diffusion characteristics. By adjusting the correction data parameter to match the material being read, the system achieves high accuracy without requiring completely separate correction systems for each material type.
2Measurement precision
If dedicated shading correction data is generated for each material type, then the shading correction accuracy is improved, but the processing time and efficiency deteriorate
Solution Approach 1:
The patent applies preliminary action by generating dedicated shading correction data in advance during manufacturing or setup, storing it for later use. This allows the system to have material-specific correction data ready when needed, achieving high accuracy without adding processing time during actual image reading operations.
3Adaptability or versatility
If multiple light sources are controlled to match specific diffusion characteristics, then the adaptability to different materials is improved, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing the light source control unit to handle multiple material types through a unified control mechanism. The same control unit can adjust lighting parameters for different materials by selecting appropriate dedicated shading correction data, providing multi-functionality without requiring separate control systems for each material type.
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 flexible and efficient shading correction by generating targeted shading correction data, effectively addressing the variations in diffusion characteristics of reflected light across different materials, thereby improving image reading accuracy.
Implementation Method 1
a light source (illumination), a lens, an image sensor... acquires image data by the light from the light source reflecting off a target to be read for an image
Data Source
AI summary
An image reading device that efficiently performs shading correction that flexibly responds to changes in the diffusion properties of reflected light on the surface of a reading target efficiently performing same as a result of including: controlling a plurality of light sources so as to cause only a specific light source among the light sources to be lit; obtaining the diffusion state of a first reflected light generated by the specific light source being lit, in a state in which general shading correction data not dependent on the image reading target is generated; obtaining a diffusion state for a second reflected light generated by light being irradiated on to the reading target by the specific light source; and generating dedicated shading correction data that relies on the reading target, based on the first reflected light diffusion state, the second reflected light diffusion state, and the general shading correction data.