Adaptive Color Interpolation for Mobile Camera Noise Reduction

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Solution Overview

Problem

Existing image processing techniques for digital color sensors face challenges in achieving consistent image quality due to computational burdens and artifacts, particularly in devices like mobile cameras where cost-effectiveness is crucial, and existing interpolation methods often enhance image definition in some areas while blurring others.

Innovation Solution

A method that calculates statistical parameters from pixel intensities in specific working windows to dynamically choose the most appropriate filtering algorithm for each pixel, reducing noise and artifacts by comparing these parameters with thresholds and selecting between different interpolation techniques such as low-pass, directional, or omnidirectional filtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If adaptive interpolation methods are used to improve image quality, then contour sharpness and noise reduction are enhanced, but computational burden and processing time increase

Engineering Contradiction:
Improveimage qualityVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies different interpolation algorithms to different regions of the image based on local characteristics. Edge regions use one algorithm while non-edge regions use another, optimizing processing efficiency while maintaining image quality in each specific area

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent dynamically selects interpolation algorithms based on real-time analysis of image characteristics such as edge detection and noise levels. This dynamic adaptation allows the system to optimize processing time while maintaining high image quality where needed

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If channel subdivision is performed for color interpolation, then color accuracy is improved, but circuit complexity and computational burden increase

Engineering Contradiction:
Improvecolor accuracyVSAvoidcircuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple interpolation operations into a unified processing framework. By merging the handling of different color channels and interpolation steps, it reduces circuit complexity while maintaining color accuracy through integrated processing

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If non-adaptive interpolation algorithms are used, then processing speed is improved, but image quality and artifact reduction deteriorate

Engineering Contradiction:
Improveprocessing speedVSAvoidimage quality
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the image processing into distinct stages: edge detection, algorithm selection, and interpolation execution. This segmentation allows simple fast algorithms to be used in most areas while applying more complex algorithms only where needed, balancing speed and quality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary analysis of image characteristics such as edge detection and noise assessment before selecting the interpolation algorithm. This preliminary action enables the system to choose the appropriate algorithm in advance, avoiding the need for complex real-time adaptation during interpolation

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS8144977B2Method and relative device of color interpolation of an image acquired by a digital color sensor
Publication Date: 2012.03.27 STMICROELECTRONICS SRL
  • US8144977B2 patent drawing
  • US8144977B2 patent drawing
  • US8144977B2 patent drawing

AI summary

A method calculates statistical parameters in function of stochastic momentums of the pixel intensities of a same primary color or complementary hue of a first working window (2k+1)×(2k+1), and of at least a second working window of smaller size, both centered on the pixel to be filtered and in choosing, as a function of the values of these statistical parameters, for each pixel of the color image to be filtered, the most appropriate filtering algorithm for enhancing as much as possible the contour sharpness and reducing noise and artifacts.