Image Processing Apparatus Edge Detection Fluctuation Range Threshold
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Solution Overview
Problem
Existing image processing systems face challenges in accurately detecting document regions from input images when the background color of the document is similar to the color of the document backing, leading to difficulties in distinguishing the boundary between the two.
Innovation Solution
An image processing apparatus that calculates the fluctuation range of gradation values within the document backing region, determines a threshold based on this range, and uses it to extract edge pixels corresponding to the boundary between the document and the backing, thereby enhancing the detection of the document region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the background color of the document is similar to the color of the document backing, then the document can be printed with realistic background tones, but the image processing apparatus cannot accurately detect the document region boundary
Solution Approach 1:
The patent applies preliminary action by calculating the fluctuation range of gradation values in the document backing region before threshold determination. This pre-processing step establishes a baseline understanding of the backing's color variations, enabling the subsequent threshold to be specifically tuned to distinguish documents with similar colors from the backing, thereby resolving the detection accuracy issue while preserving print quality
Solution Approach 2:
The patent changes the parameter used for threshold determination from fixed or simple average values to the fluctuation range (standard deviation) of gradation values in the document backing region. This parameter change enables dynamic adaptation to different backing colors and textures, allowing accurate detection even when document background colors closely resemble the backing color
2Speed
If a fixed threshold is used for edge pixel extraction, then the processing speed is maintained, but the detection accuracy decreases when background and backing colors are similar
Solution Approach 1:
The patent applies dynamics by making the threshold dynamic rather than fixed. The threshold is calculated based on the fluctuation range of gradation values in the document backing region, allowing it to adapt to different backing characteristics. This dynamic approach maintains processing efficiency while significantly improving edge detection accuracy for documents with similar colors to the backing
3Device complexity
If the threshold is determined without considering the fluctuation range of the document backing, then the processing is simpler, but the threshold cannot adapt to different backing colors and textures
Solution Approach 1:
The patent applies self-service by enabling the threshold determination process to automatically adapt to different document backing characteristics. The system calculates the fluctuation range from the actual backing region in each image and uses this information to determine an optimal threshold, eliminating the need for manual threshold adjustment or complex pre-programming for different backing types
Data Source
AI summary
An image processing apparatus includes a processor for acquiring an input image, calculating a fluctuation range of a gradation value of a pixel within a region corresponding to a document backing in the input image, determining a threshold, based on the fluctuation range, extracting an edge pixel corresponding to a boundary between a document and the document backing from the input image using the threshold, detecting a document region from the edge pixel, and an output device for outputting an image obtained by cutting a region corresponding to the document region from the input image.