Image Sensor Autofocus via Texture-Weighted Phase Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional focal plane phase detection autofocus systems face challenges in achieving high-precision phase difference detection while minimizing image quality degradation, due to constraints on the arrangement of light-shielded pixels.

Innovation Solution

An image sensor with light-shielded pixels arranged in a matrix, a setting unit to determine texture and set weighting coefficients, a calculation unit to calculate correlation values, and a generation unit to produce a degree-of-correlation histogram for precise phase difference detection, allowing flexible pixel arrangement and improved detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If light-shielded pixels are arranged in pairs (right-side and left-side) for phase difference detection, then phase difference detection capability is improved, but arrangement flexibility is reduced and image quality degradation increases

Engineering Contradiction:

Improvephase difference detection precisionVSAvoidpixel arrangement flexibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent segments the light-shielded pixels into multiple independent groups arranged in different straight lines rather than requiring paired arrangements. Each group can independently perform phase difference detection, allowing flexible distribution across the pixel array without needing symmetric pair configurations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different arrangement strategies to different regions of the pixel array. Light-shielded pixels are arranged in multiple straight lines with different orientations and positions, allowing each region to be optimized for its specific imaging requirements while maintaining overall arrangement flexibility.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If light-shielded pixels are densely arranged for high-precision phase difference detection, then detection precision is improved, but image quality degradation increases

Engineering Contradiction:

Improvephase difference detection precisionVSAvoidimage quality degradation

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses a sparse arrangement of light-shielded pixels rather than dense packing. By strategically placing light-shielded pixels in multiple straight lines across the array, sufficient phase difference detection capability is achieved without the excessive pixel density that would cause significant image quality degradation.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent transitions from one-dimensional paired arrangements to multi-dimensional distributed arrangements. Light-shielded pixels are positioned in multiple straight lines with different orientations, utilizing two-dimensional spatial distribution to achieve detection precision without requiring high local density.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If conventional paired light-shielded pixel arrangement is used, then phase difference detection is achieved, but the constraints on arrangement reduce system adaptability

Engineering Contradiction:

Improvephase difference detection capabilityVSAvoidarrangement constraints

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a universal pixel arrangement system where light-shielded pixels can be distributed in multiple straight lines with different orientations and positions. This multi-functional arrangement can adapt to various imaging scenarios and focal plane requirements without being constrained to a single paired configuration pattern.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10212332B2Image sensor, calculation method, and electronic device for autofocus

Publication Date: 2019.02.19 SONY GROUP CORP

AI summary

The present disclosure relates to an image sensor, calculation method, and electronic device that increase flexibility of the arrangement of light-shielded pixels and detect the phase difference with high precision. According to an aspect of the present disclosure, an image sensor includes: a pixel unit in which light-shielded pixels are arranged among normal pixels; a setting unit (texture determination unit) configured to determine texture around the light-shielded pixel as a pixel of interest present in a region of interest, and set a weighting coefficient on the basis of the texture; a calculation unit (correlation calculation unit) configured to calculate a correlation value between a pixel value of the light-shielded pixel and a pixel value of the normal pixel around the light-shielded pixel; and a generation unit (phase difference calculation unit) configured to generate a degree-of-correlation histogram. The present disclosure is applicable to an imaging apparatus with focal plane phase detection AF.