Pixel-Adaptive Digital Image Sharpening via Edge and Noise Detection
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Solution Overview
Problem
Existing digital image sharpening algorithms amplify noise content alongside increasing image sharpness, failing to enhance sharpness without noise amplification.
Innovation Solution
A method and system that determine edge and noise parameters for each pixel to calculate a scaling factor, applying it on a pixel-by-pixel basis to sharpen digital images while minimizing noise amplification, using an edge detector, noise detector, scaling module, and image sharpening module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional image sharpening algorithms (unsharp masking, high pass filtering) are applied to increase image sharpness, then the sharpness of the output image is improved, but the noise content of the image is amplified
Solution Approach 1:
The patent applies different sharpening strengths to different regions of the image based on edge detection. Edges are identified using gradient magnitude, and the sharpening algorithm applies higher scaling factors to edge regions while using lower or zero scaling factors for non-edge regions. This local differentiation allows sharpness enhancement without uniformly amplifying noise across the entire image.
Solution Approach 2:
The patent dynamically adjusts the scaling factor parameter α in the unsharp masking equation Ym,n=Xm,n+α(Xm,n−Sm,n) based on edge detection results. The scaling factor is set to different values for edge pixels versus non-edge pixels, allowing the system to change the sharpening intensity parameter adaptively to achieve sharpness without excessive noise amplification.
2Manufacturing precision
If a larger scaling factor α is used in unsharp masking to increase sharpness, then the output image becomes sharper, but noise amplification increases
Solution Approach 1:
Instead of applying a uniform large scaling factor across the entire image, the patent calculates different scaling factors for different pixels based on edge detection. Edge pixels receive higher scaling factors for sharpness enhancement, while non-edge pixels receive lower or zero scaling factors, preventing unnecessary noise amplification in flat regions.
Solution Approach 2:
The patent makes the scaling factor dynamic rather than static. The scaling factor αm,n varies from pixel to pixel based on real-time edge detection results, allowing the system to adapt the sharpening intensity to local image characteristics and minimize noise amplification where edges are not present.
Data Source
AI summary
Disclosed is a method for sharpening a digital image captured by a digital imaging device, the method comprising, for each pixel Xm,n of the digital image: a) at an edge detector determining an edge parameter E, the edge parameter E providing an indication of whether the pixel Xm,n is at an edge of the digital image; b) at a noose detector determining a noise parameter σ, the noise parameter σ providing an indication of whether the pixel Xm,n is a noise in the digital image; c) at a scaling module determining a scaling factor αm,n based on a combination of the edge parameter E and the noise parameter σ; and d) at an image sharpening module applying the scaling factor αm,n on a pixel by pixel basis to sharpen the digital image to get a sharpened pixel Ym,n.