Phase disparity engine low-power scene detection

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Solution Overview

Problem

The increasing number of autofocus points and phase detection pixels in image capture devices leads to a significant increase in phase disparity data computations, resulting in higher power consumption, especially since many image frames cover the same scene, necessitating a method to reduce unnecessary computations.

Innovation Solution

Implementing a phase disparity engine that computes phase disparity data for an initial image frame and determines if subsequent frames depict the same scene, allowing for the reuse of previous data if no scene change is detected, thereby reducing computational load and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If phase disparity data is computed for every image frame, then autofocus accuracy is maintained, but power consumption increases significantly

Engineering Contradiction:

Improveautofocus accuracyVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary scene comparison before computing phase disparity data. By checking whether the current image frame depicts a different scene from the previous frame using a simplified comparison method, the system determines in advance whether full phase disparity computation is necessary, thereby avoiding unnecessary computations and reducing power consumption while maintaining autofocus accuracy when needed

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of performing complete phase disparity computation for every frame, the system applies a partial action by first performing a lightweight scene change detection. Only when this preliminary check indicates a scene change does the system proceed to the full phase disparity computation, thus applying computation only partially and selectively rather than excessively for all frames

Inventive Principle:

Principle #16Partial or excessive action

2Measurement precision

If full resolution phase disparity data is processed, then autofocus precision is improved, but computational resources are consumed

Engineering Contradiction:

Improvephase disparity precisionVSAvoidcomputational power

Core Design Contradiction:

Measurement precisionVSPower

Solution Approach 1:

The system performs preliminary scene comparison using a simplified method before committing to full resolution phase disparity computation. This preliminary action filters out frames that do not require precise measurement, thereby reducing overall computational power consumption while maintaining full precision when actually needed for autofocus

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10375293B2Phase disparity engine with low-power mode

Publication Date: 2019.08.06 QUALCOMM INC

AI summary

A method provides phase disparity data. First phase disparity data for a first image frame of a first scene is computed using a phase disparity engine of an image capture device. The method determines whether the image capture device is receiving light from a second scene that is different from the first scene and corresponds to a second image frame. The phase disparity engine discontinues computing of phase disparity data, in response to a determination that the second scene is not different from the first scene. The first phase disparity data are output in connection with the second image frame, in response to determining that the second scene is not different from the first scene.