Banding Defect Detection in Digital Imaging Systems
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Solution Overview
Problem
Current digital imaging systems face challenges in detecting and analyzing banding defects, which are periodic variations in printing intensity that can indicate mechanical or electronic issues, making it difficult to maintain image quality and identify the source of defects.
Innovation Solution
A region-based banding detection method that involves scanning digital images, identifying segmented regions, determining banding frequency information, and using color vector analysis to identify the color separation where banding defects originate, allowing for improved detection and estimation of defect amplitudes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If test patterns are used for banding detection, then measurement precision is improved, but productivity deteriorates due to waste of test pages
Solution Approach 1:
The patent uses copies of customer pages (real printed output) instead of dedicated test patterns for banding detection. The system captures images of actual customer pages and analyzes them for banding defects, thereby eliminating the need for separate test pages while maintaining detection capability through intelligent image processing algorithms.
Solution Approach 2:
The patent makes the printing system multi-functional by enabling it to perform both customer printing and quality detection using the same output. The system analyzes banding in real customer pages, allowing the printer to serve dual purposes: producing customer documents and self-diagnosing quality issues without requiring dedicated test resources.
2Productivity
If region-based banding detection is used on customer pages, then productivity is improved by reducing test page waste, but measurement precision may deteriorate compared to test patterns
Solution Approach 1:
The patent extracts and isolates specific regions from customer pages that are suitable for banding analysis. The system identifies uniform regions (such as solid color areas or halftone regions) within customer pages and extracts these for dedicated banding detection, separating the detection task from the complex image content while maintaining accuracy.
Solution Approach 2:
The patent applies different analysis methods to different regions of customer pages based on their characteristics. The system identifies uniform regions versus non-uniform regions and applies appropriate banding detection algorithms to each, optimizing measurement precision for each region type while maintaining overall system productivity.
3Ease of operation
If color vector analysis is used to identify color separation, then device complexity increases, but ease of operation improves for diagnosing banding sources
Solution Approach 1:
The patent replaces physical inspection methods with automated color vector analysis. Instead of manual examination of printed outputs to identify which color separation (Cyan, Magenta, Yellow, or Black) causes banding, the system uses computational color space transformation and vector analysis to automatically diagnose the defective color channel, simplifying operator tasks despite increased computational complexity.
Data Source
AI summary
What is disclosed is a novel system and method for banding defect detection in user document images to improve image quality trend analysis in multifunction digital imaging system architectures. The present banding detection process uses region-based, time sequence analysis, and graylevels of image regions in a collection of a sequence of regions, to improve banding detection. The present method independently analyzes the colorant separations to detect banding due to sources that are colorant-dependent, e.g., due to a single developer housing. This identification can be performed in the presence of multiple banding defects.