Halftone Image Dot Frequency Adjustment for Defect Diagnosis
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Solution Overview
Problem
Existing image forming apparatus failure diagnosis techniques face challenges in accurately identifying image defects, particularly in halftone image portions, due to changes in dot patterns during halftone processing, which can lead to unstable diagnosis results.
Innovation Solution
The image forming apparatus generates halftone images with a dot pattern frequency higher than usual for test images, allowing for more precise identification of failures by comparing scanned images with input images, using advanced filtering and binarization processes to emphasize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a normal dot pattern frequency is used in halftone processing for test images, then the printing system operates normally for regular images, but the identification accuracy of image defects decreases
Solution Approach 1:
The patent applies different dot pattern frequencies to different purposes: high frequency for test images to enhance defect detection, and normal frequency for regular images to maintain printing quality. This local differentiation resolves the contradiction by optimizing each case for its specific requirement.
Solution Approach 2:
The patent changes the dot pattern frequency parameter specifically for test images during halftone processing. By adjusting this parameter to a higher value for diagnostic purposes while maintaining normal values for regular printing, the system achieves both accurate defect identification and normal printing operation.
2Reliability
If halftone processing is performed with standard dot patterns, then regular printing requirements are met, but image defects become indistinguishable from dot pattern variations
Solution Approach 1:
The patent applies preliminary anti-action by using high-frequency dot patterns in test images to prevent the confusion between dot pattern variations and actual defects. The distinctive high-frequency pattern creates a baseline that makes abnormal defects clearly distinguishable, thereby ensuring stable and reliable diagnosis results.
3Device complexity
If the same dot pattern is used for both test images and regular images, then processing is simplified, but defect detection accuracy decreases
Solution Approach 1:
The patent introduces dynamics by making the dot pattern frequency adjustable based on the image type. The system dynamically selects high frequency for test images and normal frequency for regular images, allowing the processing to adapt to different requirements without requiring completely separate processing paths.
Data Source
AI summary
In the image forming method, a halftone image is generated by performing halftone processing for an input image, a scanned image of a printed material on which on which the halftone image is printed is obtained, and a failure component of an image forming apparatus is identified based on a difference between the scanned image and the input image. In the generation, the halftone image is generated by representing a dot pattern of a halftone portion in a case where the input image is a test image for the failure diagnosis by a dot pattern whose frequency is relatively higher than that of a dot pattern that is applied to the halftone portion in a case where the input image is an image other than the test image.