Impulse Noise Filtering via Intensity Difference Detection
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Solution Overview
Problem
Conventional impulse noise filtering methods are inadequate in accurately identifying and reducing impulse noise in image signals, leading to decreased image quality due to simplistic approaches and incorrect pixel replacement.
Innovation Solution
An impulse noise filtering device comprising a signal intensity detector, intensity difference calculator, and filtering circuit, optionally incorporating edge detectors, low-pass filters, and pixel difference detectors to determine and filter out noise based on intensity and edge information, ensuring accurate noise reduction without degrading image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the luminance value of the sub-biggest (or sub-least) pixel is used to replace the original luminance value of the biggest (or least) pixel, then impulse noise is reduced, but image quality deteriorates
Solution Approach 1:
The patent changes the parameter used for noise detection from simple luminance comparison to intensity difference calculation. By calculating the absolute difference between the extreme pixel intensity and the median intensity of the window, the method creates a new parameter (intensity difference) that better distinguishes impulse noise from actual image features, thus reducing false filtering while maintaining image quality
Solution Approach 2:
The patent segments the filtering process into distinct stages: first detecting extreme pixels, then calculating intensity differences, comparing against threshold values, and finally applying selective filtering. This segmentation allows the system to apply different processing rules to different pixels based on their characteristics, preserving important image features while removing actual noise
2Device complexity
If simple luminance comparison is used to identify impulse noise, then the filtering process is simple, but noise detection accuracy deteriorates
Solution Approach 1:
The patent introduces an intermediary parameter (intensity difference) between the raw luminance values and the final noise determination. Instead of directly comparing luminance values, the system first calculates the difference between extreme pixel intensity and median intensity, then compares this difference against a threshold. This intermediary step provides a more reliable basis for noise detection while maintaining computational efficiency
Solution Approach 2:
The patent performs preliminary calculations (calculating median intensity of the window, computing intensity differences for extreme pixels) before making the final noise determination. This preliminary action prepares the necessary data in advance, allowing for more accurate noise detection without significantly increasing overall processing complexity
Data Source
AI summary
The present invention provides a device and a method for reducing impulse noise. The device includes a signal intensity detector, an intensity difference calculator, and a filtering circuit. The signal intensity detector receives an image signal and determines a first pixel having an extreme intensity, and a second pixel having a second extreme intensity of a window of the image frame corresponding to the image signal. The intensity difference calculator determines the intensity difference between the first pixel and the second pixel. The filtering circuit receives the image signal and optionally filters the image signal for reducing the impulse noise according to the intensity difference between the first pixel and the second pixel.