Focus Detection Reliability Display for Manual Focus Adjustment
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Solution Overview
Problem
Existing focus detection methods, such as on-imaging plane phase difference detection, face challenges in accuracy due to subject blur, aperture changes, and low illuminance, leading to unstable focus assist displays and user discomfort during manual focus adjustments in high-definition video cameras.
Innovation Solution
A display control apparatus and method that detects focus state and reliability using an image sensor, adjusting the display format of focus assist indicators based on detected reliability, ensuring stable focus assist functionality across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If on-imaging plane phase difference detection method is used for focus detection, then focus detection can be performed during image shooting in live view mode, but detection accuracy decreases when subject image is greatly blurred, aperture is small, or illuminance is low
Solution Approach 1:
The patent introduces a focus detection reliability determination unit that acts as an intermediary between the phase difference detection unit and the display control unit. This intermediary evaluates the reliability of focus detection results by analyzing image signal characteristics (such as signal strength, contrast, and phase difference magnitude) and determines whether the detected focus state is trustworthy. When reliability is low (due to blur, small aperture, or low illuminance), the system can switch to alternative focus detection methods or display appropriate warnings, thus maintaining measurement precision while preserving the automated live view focus detection capability.
2Adaptability or versatility
If focus detection is performed using phase difference method with varying aperture and illuminance conditions, then the camera can adapt to different shooting environments, but detection accuracy becomes unstable and varies with aperture size and lighting conditions
Solution Approach 1:
The patent implements dynamic adaptation by making the focus detection system responsive to changing shooting conditions. The focus detection reliability determination unit continuously monitors image signal characteristics and dynamically adjusts the reliability assessment based on current aperture size, illuminance levels, and subject conditions. When conditions are favorable (large aperture, good illuminance), the system uses phase difference detection with high confidence. When conditions deteriorate (small aperture, low illuminance), the system reduces reliance on phase difference detection or switches to alternative methods, thus maintaining reliability while preserving adaptability to various shooting environments.
Data Source
AI summary
A display control apparatus, comprises: a focus detection unit configured to detect, based on an image signal obtainable from an image sensor, a focus state and reliability of the image signal; and a display control unit configured to display in a display unit, when focus adjustment is performed by a manual operation, an index that indicates the focus state that was detected by the focus detection unit, wherein the display control unit changes a display format of the index according to the reliability.