Image Signal Processor Phase Image Replacement

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Solution Overview

Problem

Conventional image sensors with phase difference detection pixels experience image quality deterioration due to disparities between phase images caused by optical phenomena, leading to reduced image sharpness and signal-to-noise ratio (SNR) due to differences in exposure times and photodiode shielding.

Innovation Solution

An image signal processor system that includes an image sensor with pixels having photoelectric conversion elements with different exposure times, where the processor receives and processes images from these elements to detect disparities and replace or interpolate them, ensuring optimal image output by adjusting exposure times and combining images based on saturation and SNR conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple photodiodes with different exposure times are used in each pixel for phase difference detection, then phase difference detection capability is improved, but image quality deteriorates due to disparities between phase images

Engineering Contradiction:

Improvephase difference detection capabilityVSAvoidimage quality

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The pixel is segmented into multiple photodiodes (first and second photodiodes) with different exposure times, allowing each photodiode to capture images at different exposure levels. This segmentation enables phase difference detection while providing multiple image versions for quality selection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the exposure time parameter for different photodiodes within the same pixel. The first photodiode uses a first exposure time while the second photodiode uses a second exposure time, creating phase images with different exposure characteristics that can be selectively combined or replaced to maintain image quality.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If photodiode shielding is used for phase difference detection, then phase difference detection is enabled, but signal-to-noise ratio decreases

Engineering Contradiction:

Improvephase difference detectionVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The invention dynamically selects which photodiode image to use based on exposure conditions. The image signal processor compares images from photodiodes with different exposure times and selectively replaces or combines them, adapting to varying lighting conditions to maintain optimal signal-to-noise ratio while enabling phase difference detection.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If phase images with different exposure times are combined, then phase difference detection is achieved, but image sharpness deteriorates due to exposure disparities

Engineering Contradiction:

Improvephase difference detectionVSAvoidimage sharpness

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The image signal processor implements feedback by comparing images from photodiodes with different exposure times and determining whether replacement or combination is needed. This feedback mechanism ensures that only images with appropriate exposure matching are combined, preventing sharpness deterioration while achieving phase difference detection.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

Instead of simply combining all phase images regardless of exposure matching, the invention inverts the approach by selectively replacing images with mismatched exposure times. The processor identifies and replaces poorly exposed images with better-exposed alternatives from the same pixel, thereby maintaining sharpness while enabling phase difference detection.

Inventive Principle:

Principle #13The other way round (Inversion)

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 enhances image sharpness and SNR by accurately combining and replacing phase images, mitigating the effects of exposure time disparities and improving image quality under varying illumination conditions.

Implementation Method 1

a first pixel including a first photoelectric conversion element of a first phase group and configured to have a first exposure and the second photoelectric conversion element of a second phase group and configured to have a second exposure

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS9794469B2Image signal processor with image replacement and mobile computing device including the same

Publication Date: 2017.10.17 SAMSUNG ELECTRONICS CO LTD

AI summary

A system, comprising: an image sensor including: a first pixel including a first photoelectric conversion element of a first phase group and configured to have a first exposure and the second photoelectric conversion element of a second phase group and configured to have a second exposure; and a second pixel including a third photoelectric conversion element of the first phase group and configured to have the second exposure and a fourth photoelectric conversion element of the second phase group and configured to have the first exposure; and an image signal processor coupled to the image sensor and configured to: receive a first image from the image sensor; receive a second image from the image sensor; and configured to output an image based on at least one of the first image and the second image; wherein the first exposure is longer than the second exposure.