Focus Adjustment Device Segmentation for Hunting Prevention
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Solution Overview
Problem
Existing focus adjustment devices face challenges in accurately focusing on subjects in significantly defocused states, often resulting in hunting between near and far objects due to mixed focus detection regions, and suffer from reduced accuracy and increased calculation complexity in wide focus detection regions.
Innovation Solution
A focus adjustment device and method that set both a first and second focus detection region, with the second region being narrower, allowing for phase difference detection and reliability determination, enabling focus adjustment based on the most reliable phase difference amount, switching between the two when necessary to prevent erroneous focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wide focus detection region is set to detect significantly defocused states, then the detection range is improved, but hunting occurs between near and far subjects and focusing accuracy deteriorates
Solution Approach 1:
The focus detection region is divided into multiple sub-regions (first through fourth regions) with different widths. The controller selectively uses narrow sub-regions (second and fourth regions) for phase difference detection to avoid hunting between near and far subjects, while maintaining the ability to detect significantly defocused states through the overall wide region structure.
Solution Approach 2:
The controller dynamically selects which focus detection region to use based on the current focus state. When the focus lens is in a significantly defocused state, the wide first and third regions are utilized. As the focus lens approaches the in-focus state, the controller transitions to using the narrow second and fourth regions to prevent hunting and improve focusing accuracy.
2Measurement precision
If a narrow focus detection region is used to prevent hunting, then focusing accuracy is improved, but the ability to detect significantly defocused states is lost
Solution Approach 1:
The focus detection region is segmented into multiple sub-regions with different widths positioned at different locations. Narrow second and fourth regions provide accurate phase difference detection for preventing hunting, while wide first and third regions extend the detection capability to significantly defocused states. The controller selects appropriate sub-regions based on the current focus state.
Solution Approach 2:
Multiple focus detection regions are pre-configured with different widths and positions before focus detection begins. This allows the controller to immediately select the appropriate region based on the current focus state without requiring real-time region adjustment, enabling rapid switching between wide and narrow regions during focus adjustment.
3Measurement precision
If calculation is performed without simplification in wide focus detection regions, then detection accuracy is improved, but calculation time increases
Solution Approach 1:
The wide focus detection region is divided into multiple narrow sub-regions. Phase difference detection is performed on these narrow sub-regions which require less calculation resources, yet still provide accurate focus detection. This segmentation approach reduces calculation time while maintaining detection accuracy by focusing computation on relevant narrow areas rather than processing the entire wide region.
Solution Approach 2:
The controller extracts and uses only the necessary narrow portions (second and fourth regions) from the wide focus detection region for phase difference detection. This extraction approach avoids performing unnecessary calculations on the entire wide region, reducing calculation time while maintaining the ability to detect significantly defocused states through the overall region structure.
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 accurate and reliable focus adjustment on the intended subject by distinguishing between reliable and unreliable focus detection results, preventing hunting and improving processing speed by selectively using narrow focus detection regions for precise calculations.
Implementation Method 1
subject light flux from the photographing lens to pupil division and detecting phase difference of resulting subject images
Implementation Method 2
detecting phase difference of resulting subject images
Data Source
AI summary
In a focus adjustment device that images a subject that has been subjected to pupil division to generate image data, and carries out a focus adjustment operation based on the image data, a focus adjustment operation is carried out based on a first phase difference amount in the event that it has been determined that the first phase difference amount is larger than a first threshold value, and then by executing focus detection after the focus adjustment operation, in the event that it has been determined that reliability of both the first phase difference amount and the second phase difference amount is high, and that a difference between the two is smaller than a second threshold value, and that it has been determined that the first phase difference amount is smaller than the first threshold value, a focus adjustment operation is carried out based on a second phase difference amount.