Focus Detection Region Adjustment for Low Contrast Objects
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Solution Overview
Problem
Conventional image capturing apparatuses face difficulties in achieving accurate focus detection when the object has low contrast, leading to incorrect focus detection and potential misalignment during auto-focus and tracking processes.
Innovation Solution
A focus detecting apparatus that includes an acquiring unit, a receiving unit, a setting unit, an object detecting unit, a focus detection unit, and a calculating unit, which sets a focus detection region based on a predetermined index related to the focusing state, adjusting the region if the initial designated position has low contrast to ensure accurate focus detection by selecting a nearby region with higher contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If template matching is used to track an object in a low contrast region, then the object can be continuously detected, but focus detection becomes difficult and may fail
Solution Approach 1:
The patent changes the parameter of focus detection region selection by evaluating contrast levels of multiple candidate regions and selecting the region with sufficient contrast. When the initially designated region has low contrast, the system automatically selects an alternative region with higher contrast, thereby maintaining focus detection accuracy while preserving object tracking continuity.
2Ease of operation
If a user designates a position by touching the display screen, then the operation is simple and intuitive, but the designated position may be incorrect (e.g., contour or finger covering the object)
Solution Approach 1:
The patent implements feedback by evaluating the contrast level of the region designated by user input. If the designated region has low contrast (indicating possible incorrect designation), the system provides feedback by automatically selecting a different region with higher contrast, thereby correcting potential errors in user designation while maintaining ease of operation.
3Reliability
If focus detection is inhibited when contrast is low, then tracking and AF control are prevented, but this reduces productivity and user experience
Solution Approach 1:
The patent performs preliminary action by proactively evaluating contrast levels of multiple candidate regions before initiating focus detection. When a suitable region with adequate contrast is identified, the system pre-selects this region and proceeds with autofocus processing, thereby avoiding delays and maintaining productivity while ensuring reliable focus detection.
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
This solution enables highly accurate focus detection and tracking even when the initially designated object has low contrast, improving the reliability of auto-focus and tracking processes by correcting the focus detection region to one with higher contrast, thus preventing misalignment and ensuring proper focus on the intended object.
Implementation Method 1
an acquiring unit configured to acquire an image signal generated by an image capturing unit that performs photoelectric conversion on light passing through an imaging optical system
Data Source
AI summary
A focus detecting apparatus includes a receiving unit receiving designation of a position in a region of an image, a setting unit setting a first region in the image, an object detecting unit detecting a region of an object corresponding to the first region in continuously acquired images, a focus detection unit detecting a focusing state based on a signal from the image capturing unit corresponding to the detected object region, and a calculating unit calculating a predetermined index related to focusing state. If the predetermined index of a second region indicates a first state, the setting unit sets the first region based on the second region. If the predetermined index of the second region indicates a second state and the predetermined index of a third region near the second region indicates the first state, the setting unit sets the first region based on the third region.