Image Processing Apparatus Test Pattern Correction for Uneven Density
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Solution Overview
Problem
Conventional image processing apparatuses face challenges in eliminating or reducing periodic uneven density in image forming sections due to rotational speed variations and module eccentricities, requiring complex configurations and high-resolution density detection systems.
Innovation Solution
An image processing apparatus with a pattern generation unit, selection unit, and image correction unit that generates and selects test patterns to correct uneven density, using pre-determined waveforms and phase adjustments to simplify the configuration and reduce periodic uneven density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional density detection methods are used to correct periodic uneven density, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses test patterns that replicate the periodicity characteristics of the image forming section to indirectly measure uneven density. Instead of directly detecting density with high-precision sensors, the system creates test images with known periodic patterns, detects their output characteristics, and uses this information to generate correction data. This copying approach allows accurate measurement without requiring complex detection equipment.
Solution Approach 2:
The patent introduces test patterns as an intermediary between the image forming section and the detection system. These test patterns serve as a mediator that translates the periodic uneven density characteristics into detectable signal variations. By detecting changes in the test pattern output rather than directly measuring density, the system achieves accurate measurement with simpler detection equipment.
2Measurement precision
If high-resolution density detection devices are used to detect periodic uneven density, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
Instead of using expensive high-resolution scanners to directly measure density, the patent creates test patterns that copy the periodic characteristics of the image forming section. The detection system only needs to measure variations in these test patterns, not the entire image density distribution. This approach achieves the same measurement precision with much simpler and less expensive equipment.
Solution Approach 2:
The patent applies partial action by focusing detection efforts only on specific test pattern regions that contain the periodicity information, rather than scanning and analyzing the entire image. This selective measurement approach maintains measurement precision while significantly reducing the complexity and scale of the detection device required.
3Manufacturing precision
If correction parameters are determined based on all periodicity information, then manufacturing precision is improved, but measurement and detection difficulty increases
Solution Approach 1:
The patent extracts only the essential periodicity information needed for correction by using test patterns with known periodic characteristics. Instead of measuring and analyzing all periodicity parameters (frequency, phase, amplitude) of the actual image forming section, the system uses test patterns that embody these characteristics and extracts correction data from the simplified test pattern measurements. This extraction approach reduces measurement complexity while maintaining correction precision.
Solution Approach 2:
The patent changes the measurement parameters from direct density measurement to test pattern signal variation measurement. By transforming the measurement task into detecting signal changes in response to known test pattern inputs, the system determines correction parameters with much lower measurement difficulty. The test patterns convert complex periodicity characterization into simple signal variation detection.
Data Source
AI summary
An image processing apparatus includes a pattern generation unit configured to cause an image forming section to generate a plurality of image patterns that have periodicity unique to the image forming section and are different from each other, a selection unit configured to select one test pattern from the generated plurality of image patterns, and an image correction unit configured to correct an image based on the test pattern selected by the selection unit.