Image Reading Device Shading Correction Using Black Reference Data
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Solution Overview
Problem
Existing image reading devices face challenges in sufficiently correcting density unevenness in images due to interference between outputs from multiple sensors, which conventional shading correction methods are unable to fully address.
Innovation Solution
An image reading device is configured with a sensor module where sensors are arranged in a main scanning direction, and a data generator acquires second black data from a black reference member to generate black correction data, which is used to perform shading correction, reducing density unevenness caused by sensor interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional shading correction is performed using white reference data and black reference data, then basic density uniformity is improved, but density unevenness caused by sensor interference cannot be sufficiently corrected
Solution Approach 1:
The patent applies preliminary action by acquiring black reference data before performing shading correction. The system first captures an image of a black reference member (such as a black plate or black portion of a reference sheet) and stores this black reference data. This preliminary acquisition of black reference data enables the subsequent correction process to account for sensor interference characteristics, thereby improving the accuracy of density uniformity correction.
Solution Approach 2:
The patent changes the parameter used for shading correction from conventional white-reference-only methods to a dual-reference method incorporating both white reference data and black reference data. By introducing black reference data as a new parameter and combining it with white reference data through specific correction algorithms (such as adjusting the black level compensation based on the ratio of actual black reference data to ideal black reference data), the system achieves more accurate correction of sensor interference effects.
2Productivity
If multiple sensors are arranged in the main scanning direction to increase reading speed, then productivity is improved, but interference between sensor outputs causes density unevenness
Solution Approach 1:
The patent implements feedback by using the acquired black reference data to characterize and compensate for interference effects. The system measures the actual output of the sensor array when imaging a black reference member, compares this with ideal black reference data, and uses this feedback information to adjust the shading correction algorithm. This feedback mechanism enables the system to account for and correct density unevenness caused by sensor interference while maintaining high reading speed.
Solution Approach 2:
The patent introduces a black reference member (such as a black plate or black portion of a reference sheet) as an intermediary element. This intermediary is used to capture and characterize the interference effects of the sensor array. By imaging this intermediary black reference member and using its output as black reference data, the system can indirectly measure and compensate for sensor interference without requiring changes to the sensor arrangement itself.
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 effectively reduces density unevenness in images by using black correction data that accounts for interference noise, resulting in improved image quality by correcting for actual output characteristics of the sensors.
Implementation Method 1
a sensor module including a light source that illuminates the object on the glass plate, 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 FB glass; a sensor module having a light source and a plurality of sensors; and an image processor that generates correction data to be used for shading correction and performs the shading correction on image signals by using the correction data. The plurality of sensors is arranged in a main scanning direction and is configured to form an image signal on a single line. The image processor acquires second black data by causing the plurality of sensors to acquire an image signal of a reference sheet placed on the FB glass with the light source turned on, and generates black correction data based on the second black data. By performing the shading correction by using the black correction data, the image processor corrects density unevenness, in an image, caused by interference between image signals from the plurality of sensors.