Adaptive Interpolation for CCD Image Sensors

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Solution Overview

Problem

Conventional image processing methods fail to effectively adjust edge intensity based on brightness or saturation in individual screen areas, leading to unnecessary noise amplification in dark areas and resolution loss in bright areas.

Innovation Solution

A signal processing apparatus that determines brightness or saturation for each pixel and performs adaptive interpolation, selecting between edge emphasis and averaging interpolation methods based on predetermined thresholds to reduce noise in low-brightness areas and enhance resolution in high-brightness areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional image processing methods are used, then processing is applied uniformly across the entire screen, but this causes noise amplification in dark areas and resolution loss in bright areas

Engineering Contradiction:

Improveimage qualityVSAvoidnoise amplification in dark areas

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies different interpolation methods to different regions of the image based on local brightness characteristics. Dark regions use averaging interpolation to suppress noise, while bright regions use edge-emphasis interpolation to preserve resolution. This local differentiation resolves the contradiction by tailoring processing to regional needs rather than applying uniform processing across the entire image.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The image is segmented into multiple regions based on brightness thresholds before applying interpolation. By dividing the image into dark regions (below threshold) and bright regions (above threshold), the patent can apply appropriate processing to each segment, preventing noise amplification in dark areas while maintaining resolution in bright areas.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If edge emphasis interpolation is applied uniformly, then resolution is improved in bright areas, but this causes unnecessary noise amplification in dark areas

Engineering Contradiction:

ImproveresolutionVSAvoidnoise in dark areas

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent selectively applies edge-emphasis interpolation only to bright regions where it benefits resolution, while using averaging interpolation in dark regions to avoid noise amplification. This conditional, location-dependent approach resolves the contradiction by making the interpolation method adaptive to local image characteristics rather than uniformly applied.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces dynamic selection of interpolation methods based on local brightness conditions. The processing approach changes dynamically across the image - switching between averaging and edge-emphasis methods depending on whether each pixel falls below or above the brightness threshold, rather than using a static, uniform approach.

Inventive Principle:

Principle #15Dynamics

3Reliability

If averaging interpolation is applied uniformly, then noise is reduced in dark areas, but this causes resolution loss in bright areas

Engineering Contradiction:

Improvenoise reductionVSAvoidresolution in bright areas

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies averaging interpolation only to dark regions where noise reduction is beneficial, while using edge-emphasis interpolation in bright regions to preserve resolution. This spatially-selective approach resolves the contradiction by matching the processing method to the local characteristics of each image region.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution reduces noise and improves signal-to-noise ratio in low-brightness areas while increasing resolution by edge emphasis in high-brightness areas, resulting in improved image quality.

Implementation Method 1

an imaging element having a plurality of pixels for photoelectrically converting light from a subject

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS9160937B2Signal processing apparatus and signal processing method, solid-state imaging apparatus, electronic information device, signal processing program, and computer readable storage medium

Publication Date: 2015.10.13 SHARP KK

AI summary

A signal processing apparatus 100 is achieved, capable of processing an analog pixel signal Ag obtained by photoelectric conversion in a CCD image sensor 1 such that noise will be reduced and S/N will be improved by interpolation in an area with low brightness or saturation on a display screen and resolution will be increased by edge emphasis in an area with high brightness or saturation on the display screen. The signal processing apparatus 100 for performing A/D conversion on the analog pixel signal Ag from the CCD image sensor 1, comprises an interpolation processing section 104 for adaptively switching interpolation processing for determining brightness or saturation of pixels for each pixel, and calculating a digital pixel signal of a target pixel from pixel signals of peripheral pixels positioned in the periphery of the target pixel based on the determined brightness or saturation of the target pixel.