Exposure Control Using Luminance Offset for Subject Loss

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Solution Overview

Problem

Conventional exposure compensation techniques struggle to maintain stability and accuracy, especially when a subject's face or body is partially or completely lost from the image frame, leading to potential underexposure or overexposure issues in varying lighting conditions.

Innovation Solution

An information processing apparatus and method that includes a detecting unit to identify subjects and control exposure based on luminance differences, adjusting exposure settings using a luminance offset when the subject is partially or completely lost, ensuring consistent exposure control across changing lighting conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If exposure control is based on subject luminance detection, then exposure accuracy is improved, but exposure stability deteriorates when subject is lost from image frame

Engineering Contradiction:

Improveexposure accuracyVSAvoidexposure stability

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The system performs preliminary detection and storage of luminance relationship information between the subject and background when the subject is fully visible. This pre-stored information is then reused when the subject is partially or completely lost, allowing the exposure control to maintain stability without requiring continuous subject detection.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces luminance relationship information as an intermediary element that mediates between subject detection and exposure control. When direct subject detection fails, this intermediary information serves as a substitute reference, enabling continuous exposure control based on the relationship between subject luminance and background luminance rather than direct subject measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If exposure control relies on real-time subject detection, then adaptability to lighting changes is improved, but reliability deteriorates when subject is partially or completely lost

Engineering Contradiction:

Improveadaptability to lighting changesVSAvoidexposure control reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors subject detection status and dynamically switches between two modes: using real-time subject luminance when detected, and using pre-stored luminance relationship information when subject is lost. This feedback mechanism ensures reliable exposure control adapts to the current detection state while maintaining consistency.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11570373B2Information processing apparatus, image capturing apparatus, method, and storage medium

Publication Date: 2023.01.31 CANON KK

AI summary

There is provided with an information processing apparatus. An obtaining unit obtains an image. A first detecting unit detects a subject from the image. An exposure control unit controls an exposure based on a luminance of the detected subject. A second detecting unit detects a portion of the subject from the exposure-controlled image. A storing unit stores a difference between a first luminance of the detected subject and a second luminance of the portion of the detected subject.