Focusing Control Device Subject Tracking AF
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Solution Overview
Problem
Existing imaging devices face challenges in accurately tracking and focusing on subjects due to changes in orientation or the appearance of new subjects, leading to erroneous detection and reduced focusing accuracy.
Innovation Solution
A focusing control device that determines the focusing position using a combination of subject distance information calculation, first and second evaluation units to select the most suitable setting area among multiple areas, based on similarity and partial image signal evaluation, ensuring accurate subject tracking AF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If color information or movement vector methods are used to determine tracking target area, then subject tracking capability is improved, but erroneous detection occurs when subject orientation changes or new subjects appear
Solution Approach 1:
The imaging surface is divided into multiple setting areas, and the system evaluates each area independently using contrast information. This segmentation allows the system to identify the correct tracking target even when orientation changes occur, as each area can be assessed on its own contrast characteristics without being influenced by other areas.
Solution Approach 2:
The system calculates contrast information for each setting area and uses this feedback to determine the tracking target area. By continuously evaluating contrast changes and using this information to adjust tracking decisions, the system maintains reliability even when subjects move or new subjects appear in the frame.
2Speed
If contrast information is used to detect subject movement, then movement detection capability is improved, but false detection occurs when new subjects appear in the imaging range
Solution Approach 1:
By dividing the imaging surface into multiple setting areas and evaluating contrast information for each area separately, the system can detect movement in the correct area while ignoring contrast changes in other areas where new subjects may appear. This spatial segmentation prevents false detection.
Solution Approach 2:
The system applies contrast evaluation locally to each setting area rather than globally across the entire imaging surface. This allows movement detection to be performed with high speed in the relevant local area while maintaining reliability by not being influenced by unrelated contrast changes in other areas.
3Adaptability or versatility
If multiple tracking methods are used to handle subject orientation changes, then adaptability is improved, but device complexity increases
Solution Approach 1:
The contrast information calculation unit serves multiple functions: it detects subject movement, determines tracking target areas, and handles orientation changes. By making this single component multi-functional, the system achieves high adaptability without increasing overall device complexity.
Solution Approach 2:
The system uses contrast information as a key parameter that changes with subject orientation and movement. By monitoring changes in this parameter across different setting areas, the system adapts to orientation changes and new subjects without requiring multiple separate tracking systems.
Data Source
AI summary
A focusing control device includes: a focusing position determination unit that determines a focusing position of a focus lens based on captured image signals acquired through imaging using a setting area selected among a plurality of setting areas set for an imaging surface of an imaging element that images a subject through an imaging optical system including the focus lens capable of moving in an optical axis direction; a subject distance information calculation unit as defined herein; a first evaluation unit as defined herein; and a second evaluation unit as defined herein, and the focusing position determination unit selects a setting area to be used in the determination of the focusing position, among the plurality of setting areas, based on an evaluation result using the first evaluation unit and an evaluation result using the second evaluation unit.