Image Reading Device Shading Correction for Sensor Interference
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Solution Overview
Problem
Image reading devices with multiple sensors in the main scanning direction experience density unevenness due to interference between sensor outputs, which conventional shading correction methods fail to adequately address, especially in wide reading regions like A3-size sheets, requiring correction in both main and sub-scanning directions.
Innovation Solution
The image reading device employs a sensor module with a light source and multiple sensors, using reference plates to generate black and white correction data for shading correction. It acquires second intermediate data from a reference member in the sub-scanning direction, generating black correction data at each position to correct density unevenness caused by sensor interference, effectively addressing the issue in both main and sub-scanning directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional shading correction using single reference data is applied, then correction process is simple, but density unevenness in sub-scanning direction cannot be corrected
Solution Approach 1:
The patent divides the correction process into multiple segments: acquiring black reference data at multiple positions in the sub-scanning direction, calculating intermediate data for each position, and generating position-specific black correction data. This segmentation enables correction of density unevenness across different sub-scanning positions while maintaining a systematic and manageable correction workflow.
Solution Approach 2:
The patent extends the correction approach from a single reference point to multiple positions along the sub-scanning direction, adding a dimensional aspect to the correction process. By acquiring reference data at multiple sub-scanning positions and generating position-specific correction data, the system addresses density unevenness in both main scanning and sub-scanning directions.
2Productivity
If black correction data is generated only at single position, then data processing is fast, but interference noise in image signals is not adequately corrected
Solution Approach 1:
The patent performs preliminary actions by acquiring black reference data at multiple positions in the sub-scanning direction before actual image reading. The intermediate data calculation and black correction data generation for each position are completed in advance, allowing the system to quickly apply pre-calculated correction data during actual operation, thus maintaining processing speed while improving correction accuracy.
Solution Approach 2:
The patent creates multiple copies of black correction data, each specific to a particular sub-scanning position. By generating position-specific black correction data through intermediate calculations, the system has ready-to-use correction data for each position, enabling accurate correction without real-time computation overhead during actual image reading.
3Area of stationary object
If multiple sensors are used in main scanning direction, then reading width is increased, but density unevenness due to sensor interference occurs
Solution Approach 1:
The patent applies local quality by generating black correction data specific to each position in the sub-scanning direction. Each position has its own tailored correction data that accounts for local interference conditions, allowing precise correction of density unevenness in different regions of the wide reading area without compromising overall image quality.
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 configuration significantly reduces density unevenness in images by performing shading correction using position-specific correction data, improving image quality by accounting for interference noise in both main and sub-scanning directions.
Implementation Method 1
a light source that irradiates an object and a plurality of sensors that reads light reflected from the object to acquire image signals
Data Source
AI summary
An image reading device includes an image processor that generates correction data to be used for shading correction and perform the shading correction using the correction data, and a memory that stores first black correction data to be used for the shading correction in a main scanning direction in a predetermined first position in a predetermined sub-scanning direction. The image processor generates third black data based on an image signal of a second reference plate extending in the sub-scanning direction in a predetermined second position in the main scanning direction, generates black correction data according to the sub-scanning direction based on the first black correction data and the third black data, and performs the shading correction using the black correction data so as to correct density unevenness in the main scanning direction and the sub-scanning direction caused by an interference between image signals from a plurality of sensors.