Autofocus Mode Switching for Low Illuminance Imaging
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Solution Overview
Problem
Existing autofocus systems face challenges in low illuminance environments, where passive mode autofocus accuracy and speed decrease, leading to potential focus deviation in captured images.
Innovation Solution
An imaging apparatus that automatically selects between passive and active autofocus modes based on luminance levels, using a detector to compare the luminance with a threshold to choose between contrast-based passive mode and time-of-flight active mode, ensuring high-speed and high-accuracy focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If passive mode autofocus is used, then wide distance range coverage is achieved, but autofocus speed and precision deteriorate in low illuminance environments
Solution Approach 1:
The system dynamically switches between passive mode and active mode autofocus based on detected luminance levels. When luminance exceeds a threshold, passive mode is used; when luminance falls at or below the threshold, active mode is activated. This dynamic adaptation resolves the contradiction by selecting the appropriate mode for current lighting conditions, maintaining both wide distance range coverage and autofocus precision across varying illuminance environments.
2Adaptability or versatility
If passive mode autofocus is used, then wide distance range coverage is achieved, but autofocus speed deteriorates in low illuminance environments
Solution Approach 1:
The system dynamically switches between passive mode and active mode autofocus based on detected luminance levels. When luminance exceeds a threshold, passive mode is used; when luminance falls at or below the threshold, active mode is activated. This dynamic adaptation resolves the contradiction by selecting the appropriate mode for current lighting conditions, maintaining both wide distance range coverage and autofocus speed across varying illuminance environments.
3Measurement precision
If active mode autofocus is used, then autofocus speed and precision are improved in low illuminance environments, but device complexity increases
Solution Approach 1:
The imaging apparatus integrates both passive mode and active mode autofocus capabilities within a single system, with a mode determination unit that selects between them based on luminance conditions. This multi-functionality allows the system to maintain high autofocus precision across all illuminance levels while managing complexity through automated mode selection rather than requiring manual intervention or separate dedicated systems.
4Speed
If active mode autofocus is used, then autofocus speed is improved in low illuminance environments, but device complexity increases
Solution Approach 1:
The imaging apparatus integrates both passive mode and active mode autofocus capabilities within a single system, with a mode determination unit that selects between them based on luminance conditions. This multi-functionality allows the system to maintain high autofocus speed across all illuminance levels while managing complexity through automated mode selection rather than requiring manual intervention or separate dedicated systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-speed and high-accuracy autofocus operations in various lighting conditions, including low illuminance environments, without the need for auxiliary light, thereby preventing focus deviation and enhancing image quality.
Implementation Method 1
a detector configured to detect a luminance level of a shooting environment
Implementation Method 2
The active mode calculator may calculate a shift amount of the lens using the active mode based on light emission timing of the irradiation light and the light reception timing
Data Source
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AI summary
The present technology relates to an imaging apparatus and method, and a program, capable of focusing on a subject with higher accuracy. An image sensor shoots a captured image by receiving light coming from a subject via an optical unit and by converting the light into electrical signal. A captured-image processing unit detects a luminance level of the captured image. A passive mode AF calculator calculates a shift amount of a lens in autofocusing using a passive mode, and an active mode AF calculator calculates a shift amount of a lens in autofocusing using an active mode. An AF mode determination unit selects any one of the passive mode or the active mode by comparing the luminance level with a threshold. The present technology is applicable to digital still cameras.