Edge Direction Detection Using Dynamic Pixel Array Segmentation
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Solution Overview
Problem
Existing image processing technologies face challenges in detecting edge directions with high precision, especially when magnifying images, as they often fail to accurately distinguish between horizontal and vertical directions, leading to increased operational costs and potential errors, particularly in cases of diagonal lines and textures.
Innovation Solution
An image processing apparatus and method that determines a calculation range for edge direction detection based on whether the edge is closer to a horizontal or vertical direction and its quadrant, using a combination of filters and differential operators to enhance detection precision and reduce operational costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a differential operator uses a 3×3 pixel array around a target pixel, then the operational cost is reduced, but the detection precision of edge direction is insufficient
Solution Approach 1:
The patent segments the edge direction detection process into multiple independent stages: first determining whether the edge is closer to horizontal or vertical direction using 3×3 pixel arrays, then determining the quadrant using 5×5 pixel arrays only when needed, and finally performing precise angle calculation only for edges requiring it. This segmentation allows the system to use smaller, faster 3×3 arrays for common cases while reserving 5×5 arrays for specific situations, thereby reducing overall operational cost while maintaining precision when needed.
Solution Approach 2:
The patent dynamically adjusts the pixel array size used in edge direction detection based on the detected edge characteristics. The system starts with a 3×3 pixel array for initial classification and only expands to a 5×5 pixel array when the edge direction is ambiguous or requires higher precision. This dynamic adaptation allows the system to optimize between operational cost and detection precision for each specific case rather than using a fixed array size throughout.
2Measurement precision
If a differential operator uses a 5×5 pixel array around a target pixel, then the detection precision of edge direction is enhanced, but the operational cost increases at least twice
Solution Approach 1:
The patent applies partial action by using 5×5 pixel arrays only partially - specifically only when the initial 3×3 array detection indicates that higher precision is needed. For most edges that can be clearly classified as horizontal or vertical, the system uses only the 3×3 array. The 5×5 array is used excessively for cases where the edge direction is close to diagonal or when precision is required for accurate angle measurement, thereby avoiding unnecessary computational cost for simple cases while ensuring sufficient precision for complex cases.
3Device complexity
If edge direction is detected using only the output of a differential operator, then the process is simple, but a single direction is detected even when two edges cross each other, leading to erroneous detection
Solution Approach 1:
The patent segments the edge direction detection into distinct functional stages: first using differential operators to determine horizontal vs. vertical orientation, then using additional processing to determine quadrants, and finally using angle calculation only when necessary. This segmentation prevents the simple differential operator from producing erroneous results by breaking down the detection process into manageable steps that can identify and handle crossing edges separately.
Solution Approach 2:
The patent implements feedback mechanisms where the results of initial 3×3 pixel array analysis feed back into the decision-making process for whether to perform additional 5×5 pixel array analysis. The system continuously refines the edge direction detection based on previous results, correcting erroneous detections by comparing against expected patterns and adjusting the detection process accordingly to handle crossing edges properly.
Data Source
AI summary
Provided is an image processing apparatus including a preprocessor configured to determine, based on an input image signal being input, a calculation range of calculation of detecting a direction of an edge in an image which the input image signal represents; and an edge direction detection unit configured to perform calculation within the calculation range determined based on the input image signal and detect the direction of the edge.