Imaging Device Focusing Controller Adaptive AF Switching

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing imaging devices face challenges in achieving high-speed and high-accuracy focusing control, particularly when dealing with subjects moving at high speeds or those inappropriate for either the phase difference AF method or the contrast AF method.

Innovation Solution

The proposed imaging device employs a focusing controller that selectively uses either the phase difference AF method or the contrast AF method for focusing control. It continuously performs focusing control using the phase difference AF method unless the degree of reliability falls below a threshold, at which point it switches to the contrast AF method after a predetermined number of occurrences or elapsed time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the phase difference AF method is used for focusing control, then focusing speed is improved, but focusing accuracy deteriorates when the subject is inappropriate for this method

Engineering Contradiction:

Improvefocusing speedVSAvoidfocusing accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The patent implements dynamic switching between phase difference AF and contrast AF methods based on real-time reliability assessment. The system continuously evaluates the reliability of phase difference AF measurements and transitions to contrast AF when reliability falls below a threshold, optimizing both speed and accuracy adaptively throughout the focusing process

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameter by switching between two different AF methods (phase difference AF and contrast AF) based on reliability conditions. This parameter change allows the system to maintain high focusing speed when phase difference AF is reliable while ensuring accuracy when it is not, resolving the contradiction between speed and precision

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the contrast AF method is used for focusing control, then focusing accuracy is improved, but focusing speed deteriorates

Engineering Contradiction:

Improvefocusing accuracyVSAvoidfocusing speed

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The system dynamically selects the appropriate AF method based on real-time reliability assessment. Contrast AF is activated only when phase difference AF reliability is insufficient, ensuring accuracy is maintained without unnecessarily sacrificing focusing speed during conditions where phase difference AF performs well

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If the phase difference AF method and contrast AF method are combined for focusing control, then focusing accuracy is improved, but the time until AF is completed increases

Engineering Contradiction:

Improvefocusing accuracyVSAvoidtime until AF is completed

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements conditional switching between AF methods based on reliability thresholds rather than combining both methods throughout the entire focusing process. This dynamic approach maintains high focusing speed by using phase difference AF when reliable, while ensuring accuracy by switching to contrast AF only when needed, thus avoiding the time penalty of continuous dual-method operation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system performs preliminary reliability assessment of phase difference AF measurements before committing to a focusing decision. By evaluating reliability in advance and pre-conditioning the switch to contrast AF when necessary, the system avoids unnecessary processing time while maintaining accuracy

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12326614B2Imaging device, focusing control method, and computer readable non-transitory recording medium storing a focusing control program capable of realizing focusing control at high speed with high accuracy

Publication Date: 2025.06.10 FUJIFILM CORP

AI summary

An imaging device and a focusing control method are provided. The imaging device includes: an imaging element, having pixels including phase-difference detecting pixels and imaging a subject through an imaging optical system including a focus lens; and a focusing controller, selectively performing focusing control using a phase difference AF method or focusing control using a contrast AF method in a mode in which focusing control for focusing on a main subject by driving the focus lens is continuously performed multiple times. The focusing controller performs the focusing control using the contrast AF method in a case where a state in which a degree of reliability of the focusing control using the phase difference AF method is equal to or less than a threshold value persists N times (N=2 or more), while the focusing control using the phase difference AF method is continuously performed.