Autofocus System Using Confidence Score and Sharpness Projection

Solution Overview

Problem

Current digital camera autofocus systems are inefficient, taking longer to determine the optimum lens position and often using redundant positions, leading to wasted computation time and power resources, resulting in suboptimal image quality and user frustration.

Innovation Solution

A method that calculates a confidence score to determine initial lens positions, generates a sharpness score dataset using curve fitting analysis, and dynamically adjusts the lens to validate the estimated focus position, allowing for efficient determination of the optimum focus position with fewer lens positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional autofocus methods test multiple lens positions to determine optimum focus, then focus accuracy can be achieved, but computation time and power consumption increase significantly

Engineering Contradiction:

Improvefocus accuracyVSAvoidcomputation time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary analysis of the image environment (contrast, texture, edge detection) before actually testing lens positions. This preliminary action provides predictive information about where the optimum focus position is likely to be, reducing the number of actual lens position tests needed while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces purely mechanical lens position testing with a hybrid approach that uses image processing algorithms and environmental analysis to predict focus positions. This substitution reduces reliance on brute-force mechanical testing, thereby reducing computation time and power consumption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If traditional autofocus methods test multiple lens positions to determine optimum focus, then focus accuracy can be achieved, but power consumption increases due to redundant positions

Engineering Contradiction:

Improvefocus accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary analysis of the image environment (contrast, texture, edge detection) before actually testing lens positions. This preliminary action provides predictive information about where the optimum focus position is likely to be, reducing the number of actual lens position tests needed while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces purely mechanical lens position testing with a hybrid approach that uses image processing algorithms and environmental analysis to predict focus positions. This substitution reduces reliance on brute-force mechanical testing, thereby reducing computation time and power consumption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If fewer lens positions are used in autofocus, then computation time and power consumption are reduced, but focus accuracy may deteriorate

Engineering Contradiction:

Improveautofocus speedVSAvoidfocus accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary analysis of the image environment (contrast, texture, edge detection) before actually testing lens positions. This preliminary action provides predictive information about where the optimum focus position is likely to be, reducing the number of actual lens position tests needed while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces purely mechanical lens position testing with a hybrid approach that uses image processing algorithms and environmental analysis to predict focus positions. This substitution reduces reliance on brute-force mechanical testing, thereby reducing computation time and power consumption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9392158B2Method and system for intelligent dynamic autofocus search

Publication Date: 2016.07.12 NVIDIA CORP

AI summary

Embodiments of the present invention initially calculate a confidence score for the image environment surrounding the subject matter in order to determine the initial number of lens positions. Once the initial lens positions are determined, a sharpness score is calculated for each determined initial lens position. Using these sharpness scores, embodiments of the present invention generate a projection used to locate an estimated optimum focus position as well as to determine an estimated sharpness score at this lens position. Embodiments of the present invention then position the lens of the camera to calculate the actual sharpness score at the estimated optimum focus position, which is then compared to the estimated optimum sharpness score previously calculated. Based on this comparison, embodiments of the present invention dynamically determine whether it has a sufficient number of lens positions to determine the optimum focus position or if additional sample lens positions are needed.