Image Processing Apparatus for Stamp Imprint Removal
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Solution Overview
Problem
Existing image processing technologies face challenges in effectively removing stamp imprints from documents, particularly when they overlap with black characters, leading to blurring or loss of text information during optical character recognition (OCR) due to the inability to accurately distinguish between black characters and stamp imprints.
Innovation Solution
An image processing apparatus that utilizes both visible and invisible light sensors to generate image data, where the apparatus determines a black-print region based on near-infrared image data and achromatizes the corresponding visible image data to restore black characters overlapped with stamp imprints, preventing their removal during stamp imprint removal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a color dropout function is used to remove stamp imprints by removing specific colors, then stamp imprint removal is achieved, but black characters overlapped with stamp imprints are blurred or lost
Solution Approach 1:
The patent segments the image processing into multiple wavelength channels (visible light and infrared light). By separating the analysis into different spectral domains, the system can identify black characters in the infrared channel where they remain distinct from stamp imprints, then use this information to guide selective processing in the visible light channel to remove stamps while preserving characters.
Solution Approach 2:
The patent introduces infrared image data as an intermediary to bridge the gap between stamp removal and character preservation. The infrared image serves as a reference that identifies character locations, which then guides the visible light image processing to protect those specific regions during stamp removal operations.
2Object-generated harmful factors
If stamp imprint removal is performed on visible image data, then stamp imprints are eliminated, but black characters cannot be distinguished from stamp imprints leading to text loss
Solution Approach 1:
The patent adds a spectral dimension by incorporating infrared light imaging alongside visible light imaging. This additional dimensional information allows the system to distinguish between black characters and stamp imprints based on their different infrared absorption characteristics, thereby improving measurement precision in text region identification.
Solution Approach 2:
The patent changes the observational parameter from solely visible light properties to include infrared light absorption properties. By measuring absorption rates in the infrared wavelength range, the system can differentiate black characters (which have specific infrared absorption characteristics) from stamp imprints, enabling accurate text region identification even when stamps are present.
3Device complexity
If only visible light reading is used, then the processing is simple, but black characters overlapped with stamp imprints cannot be accurately identified
Solution Approach 1:
The patent makes the imaging system multi-functional by using both visible light and infrared light sensors. The same scanning apparatus performs dual wavelength imaging, allowing it to both detect black characters with high accuracy and provide the basis for stamp removal, thereby justifying the increased device complexity through enhanced measurement precision and additional functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of OCR by preventing blurring or loss of black characters and improving recognition rates by restoring black characters to their original state, ensuring clear text extraction even when stamp imprints are removed.
Implementation Method 1
a second image sensor to receive reflected light of the invisible light from the subject and output invisible image data... The designated region has an absorption rate equal to or higher than a predetermined absorption rate... The designated region is an image region formed with a material including carbon
Data Source
AI summary
An image processing apparatus includes circuitry to receive visible image data obtained by reading of a subject with a sensor having sensitivity to visible light in a visible wavelength range and invisible image data obtained by reading of the subject with a sensor having sensitivity to invisible light in an invisible wavelength range. The circuitry generates image data for displaying, in a designated color, a portion of the visible image data corresponding to a designated region of the invisible image data. The designated region has an absorption rate equal to or higher than a predetermined absorption rate.