Image Processing Circuit for Ringing Artifact Removal

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Solution Overview

Problem

Existing image processing technologies suffer from ringing artifacts during up-sampling, which are difficult to remove without also blurring image details, leading to deteriorated image quality.

Innovation Solution

An image processing circuit with a deRing detection unit and a deRing filtering unit that calculates and applies regulating reference values to the display data, using edge and ringing artifact detection to determine and remove ringing artifacts while preserving image details.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a high order filter is utilized for up-sampling the image data, then the data at high frequency in the digital image can be retained, but ripples are likely to be formed due to ringing effects

Engineering Contradiction:

Improvehigh frequency data retentionVSAvoidringing artifacts

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent segments the image processing into multiple stages: first applying a high-order filter to retain high frequency data, then separately detecting and removing ringing artifacts in the frequency domain. This segmentation allows each stage to optimize for its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts ringing artifacts from the image data by transforming to frequency domain, identifying and removing the specific frequency components that cause ringing effects, while preserving the beneficial high frequency information retained by the high-order filter.

Inventive Principle:

Principle #2Taking out (Extraction)

2Object-generated harmful factors

If a low-pass filter is used to remove ringing artifacts, then ringing effects can be reduced, but image details are also removed resulting in blurring artifacts

Engineering Contradiction:

Improveringing artifacts removalVSAvoidimage detail preservation

Core Design Contradiction:

Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The patent applies different processing treatments to different frequency components locally. In the frequency domain, it selectively attenuates only the specific frequency ranges that cause ringing artifacts while maintaining the amplitude and phase characteristics of other frequency components that represent image details.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the frequency response parameters of the filtering operation by using a modified frequency response function that differs from traditional low-pass filters. This modified function allows selective removal of ringing frequencies while preserving detail frequencies through parameter optimization.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9406106B2Image processing circuit and method for removing ringing artifacts thereof

Publication Date: 2016.08.02 NOVATEK MICROELECTRONICS CORP

AI summary

An image processing circuit and a ringing artifact removing method thereof are provided. The image processing circuit includes a deRing detection unit and a deRing filtering unit. The deRing detection unit receives a plurality of display data of an input frame and calculates a regulating reference value corresponding to each display data according to the display data and the display data at adjacent display positions. The deRing filtering unit is coupled to the deRing detection unit. The deRing filtering unit receives the display data and regulates the display data according the regulating reference values respectively corresponding to the display data to output a plurality of regulated display data.