Adaptive Smoothing Filter Selection Using Gradient Histograms
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image processing methods degrade image quality due to excessive smoothing, as they only consider edge direction for selecting smoothing means, failing to adapt to various edge shapes in intensity and magnitude.
Innovation Solution
An image processing apparatus and method that calculates the direction and magnitude of pixel gradients, generates a Histogram of Oriented Gradients, and uses a storing unit to associate smoothing filters with templates of Histograms of Oriented Gradients, searching for the minimum error match to apply an adaptive smoothing filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If only edge direction is considered for selecting smoothing means, then the selection process is simple, but image quality degrades due to excessive smoothing
Solution Approach 1:
The patent extends the selection criteria from considering only edge direction to considering both edge direction and edge intensity/magnitude parameters. By incorporating multiple parameters (gradient direction, gradient magnitude) into the histogram of oriented gradients, the system achieves more precise adaptive smoothing that prevents excessive smoothing while maintaining operational simplicity through automated parameter-based selection.
2Manufacturing precision
If adaptive smoothing is implemented for various edge shapes, then image quality improves, but device complexity increases
Solution Approach 1:
The patent uses templates of histograms of oriented gradients that are pre-computed and stored in the storing unit. During processing, the system compares the current image's histogram features against these pre-stored templates to automatically select appropriate smoothing filters. This template-based approach enables adaptive smoothing for various edge shapes while managing device complexity by pre-computing and storing reference data rather than requiring complex real-time calculations.
3Adaptability or versatility
If multiple smoothing filters are stored and searched, then adaptability to different edge shapes improves, but processing time increases
Solution Approach 1:
The patent pre-computes and stores templates of histograms of oriented gradients and associates them with corresponding smoothing filters in the storing unit before actual image processing. During processing, the system only needs to compare current image features against these pre-prepared templates rather than performing complex real-time analysis, thereby achieving high adaptability to different edge shapes while minimizing processing time through preliminary preparation of reference data.
Data Source
AI summary
An image processing apparatus includes a gradient calculator that calculates a direction and a magnitude of a gradient of each pixel in an input image using neighboring pixel values; a histogram calculator that calculates a Histogram of Oriented Gradients containing plural sampled directions from the directions and the magnitudes of the gradients calculated for the pixels in a region including the pixel being processed; a storing unit that stores plural smoothing filters and associated Histograms of Oriented Gradients; a search unit that calculates errors between Histogram of Oriented Gradients calculated for the pixel being processed and the Histograms of Oriented Gradients stored in the storing unit and searches the Histogram of Oriented Gradients that has the minimum error; and a filter processing unit that acquires one of the smoothing filters stored in association with the Histogram of Oriented Gradients having the minimum error and determines a corrected pixel value of the pixel being processed by filter processing with the acquired smoothing filter.