Blank Page Detection in Multifunction Scanners
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Solution Overview
Problem
Existing methods for detecting blank pages in multifunction machines struggle to accurately identify blank pages without requiring complex cropping between front and back pages, and fail to detect information on pages with similar gray intensity levels, leading to missed detection of information on the other side viewed by transparency.
Innovation Solution
A method that scans pages, analyzes pixel values, removes edges, adjusts size, and converts to gray levels, using threshold comparisons and binarization to classify pages as blank or carrying information, while being resistant to shifts and capable of detecting real information, such as handwritten text, without user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple technique based on comparison of total level of whiteness against a threshold is used, then the detection process is simple, but it requires complex cropping between front and back pages and cannot detect information on similar intensity pages
Solution Approach 1:
The patent divides the detection process into multiple stages: first comparing total gray intensity levels of front and back pages, then performing detailed pixel-by-pixel comparison only on selected pages that pass the initial filter. This segmentation allows simple initial filtering while maintaining high detection accuracy for edge cases.
Solution Approach 2:
Instead of applying uniform threshold comparison to all pages, the patent applies different detection strategies to different pages: simple threshold comparison for clearly blank pages, and detailed pixel-by-pixel comparison with shift tolerance for pages requiring higher precision analysis.
2Power
If gray intensity level comparison is used to detect blank pages, then the method is computationally simple, but it fails to detect information on pages with similar intensity levels viewed by transparency
Solution Approach 1:
The patent implements a dynamic, multi-stage detection process that adapts its complexity based on the characteristics of each page. Pages with明显 intensity differences use simple comparison, while pages with similar intensities trigger more sophisticated pixel-by-pixel analysis with shift tolerance, optimizing computational resources while maintaining reliability.
Solution Approach 2:
The patent introduces an intermediary selection criterion that identifies pages requiring detailed analysis. This intermediary layer filters out obviously blank pages first, then applies computationally intensive pixel-by-pixel comparison only to borderline cases, balancing computational efficiency with detection reliability.
3Measurement precision
If complex cropping between front and back pages is performed, then detection accuracy improves, but processing time and computational resources increase
Solution Approach 1:
The patent performs preliminary filtering by comparing total gray intensity levels before conducting detailed pixel-by-pixel analysis. This preliminary action eliminates obviously blank pages early in the process, avoiding unnecessary computational overhead and reducing overall processing time while maintaining detection accuracy.
Solution Approach 2:
Instead of performing complete pixel-by-pixel comparison with shift tolerance on all pages, the patent applies this exhaustive analysis only to a subset of pages that pass the initial filtering stage. This partial application of the more intensive method reduces processing time while maintaining high detection accuracy for problematic cases.
Data Source
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AI summary
The invention relates to a method for detecting blank pages among sheets of a document scanned on a multifunctional machine comprising a scanner, wherein said scanner: scans (S0) two pages of at least one sheet of a document to be scanned; carries out a basic detection (S6) of a blank page on each scanned sheet; selects (S7) each sheet not comprising at least one page detected to be blank during the detection (S6); compares (S9) the two pages of said selected sheet; and classifies (S9) a page as blank when it is similar to the other page of said sheet. The invention also relates to a multifunctional machine, the machine comprising a scanner for implementing a method according to the invention.