Auto Color Mode Document Determination Threshold Logic
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Solution Overview
Problem
In auto color mode, existing image forming apparatuses cannot determine whether a document is color or monochrome until the entire document is scanned, leading to delayed image processing and reduced performance, especially for monochrome documents.
Innovation Solution
An image forming apparatus with a document determination unit that temporarily determines a document as monochrome if the color component ratio is below a threshold during scanning, allowing for immediate monochrome image processing, and switches to color processing when the ratio exceeds a threshold during processing, enabling early initiation of image processing without waiting for full scan completion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the apparatus waits for complete document scanning before determining document type, then the determination accuracy is improved, but the image processing speed deteriorates
Solution Approach 1:
The patent applies preliminary action by performing initial document type determination during the scanning process itself, rather than waiting for complete scanning. The determination unit calculates the color component ratio and compares it against thresholds to preliminarily identify whether the document is color or monochrome, allowing image processing to start before scanning completes. This resolves the contradiction by enabling early processing while maintaining accuracy through continued monitoring of the color ratio throughout scanning.
Solution Approach 2:
The patent implements feedback by continuously monitoring the color component ratio during scanning and adjusting the determination based on this feedback. The determination unit compares the calculated color ratio against predetermined thresholds and can revise the document type determination if the ratio exceeds the color threshold during scanning. This feedback mechanism ensures determination accuracy while enabling early image processing to begin, thus resolving the speed-accuracy tradeoff.
2Productivity
If the apparatus starts image processing before complete document scanning, then the processing speed is improved, but the determination accuracy deteriorates
Solution Approach 1:
The patent performs preliminary document type determination during scanning by calculating the color component ratio of the scanned portions and comparing it against thresholds. This preliminary determination enables image processing to start before scanning completes, improving speed while maintaining acceptable accuracy through the statistical significance of the sampled color ratio.
Solution Approach 2:
The system continuously monitors the color component ratio during scanning and uses this feedback to maintain or revise the document type determination. If the color ratio exceeds the color threshold during scanning, the determination is revised to color document. This feedback loop ensures that early processing decisions can be corrected if needed, maintaining determination accuracy while enabling speed improvement through early processing initiation.
3Device complexity
If the apparatus uses a single color threshold value for document determination, then the device complexity is reduced, but the determination accuracy deteriorates
Solution Approach 1:
The patent applies parameter changes by using multiple threshold values (color threshold and monochrome threshold) instead of a single threshold. The determination unit compares the color component ratio against both thresholds to accurately determine document type. This multi-threshold approach improves determination accuracy by accounting for different document types more precisely, while the thresholds are managed through simple comparison logic that doesn't significantly increase device complexity.
Data Source
AI summary
Provided is an image forming apparatus that speeds up the performance in the auto color mode. A document reading unit reads a document and outputs image data. A document determination unit temporarily determines the document as a monochrome document when the ratio of the color components of the document is equal to or less than the monochrome threshold value at a specific timing after the document reading unit starts reading the document. An image processing unit performs monochrome image processing on the image data. A document determination unit determines that the document is a color document when the ratio of the color components of the image data is equal to or more than the color threshold value while the image processing for the monochrome document is being performed.