Variable Focus Step Width for Front Region Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional focus bracket shooting techniques capture images at equal intervals based on an in-focus position, which can result in difficulty focusing on objects like flowers or clocks, where the front regions such as petals or clock faces are challenging to bring into focus.
Innovation Solution
An image capture apparatus with a sensor that photoelectrically converts light fluxes through different pupil regions of an optical system, allowing for variable step widths in focus lens positioning based on focus detection results, enabling multiple image captures with varying step widths from the in-focus position towards both the closest and infinity sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If images are captured at equal intervals based on in-focus position, then the focusing process is simple and systematic, but front regions of objects like flowers or clocks cannot be properly focused
Solution Approach 1:
The patent applies asymmetry by setting different step widths for different directions from the in-focus position. Specifically, the step width toward the closest side (near focus distance) is made smaller than the step width toward the infinity side (far focus distance). This asymmetric step width configuration allows finer control over focus positioning for front regions of objects while maintaining broader coverage for background regions, thereby resolving the contradiction between operational simplicity and focus precision.
Solution Approach 2:
The patent implements local quality by applying different step width parameters to different spatial regions relative to the in-focus position. The closer region (toward nearest focusable distance) uses a smaller step width for precise control, while the farther region (toward infinity) uses a larger step width. This localized differentiation of step width quality enables accurate focusing on front regions without compromising the overall focus bracket shooting process.
2Adaptability or versatility
If multiple images are captured with different focal distances, then depth-composed images can be created, but the number of captured images increases
Solution Approach 1:
The patent applies dynamics by making the step width variable rather than fixed. The step width changes dynamically based on the direction from the in-focus position: smaller step widths are used when moving toward the closest focus distance, while larger step widths are used when moving toward infinity. This dynamic adjustment of step width allows the system to achieve effective depth composition with an optimized number of captured images, reducing the total quantity compared to uniform step width approaches.
3Measurement precision
If the in-focus position is shifted toward the closest side, then front regions of objects can be focused, but the step width control becomes more complex
Solution Approach 1:
The patent implements parameter changes by modifying the step width parameter based on the direction of focus movement. When the focus position is shifted toward the closest side, a smaller step width parameter is applied to maintain precision. When shifted toward infinity, a larger step width parameter is used. This parameter change strategy enables accurate focusing on front regions while managing system complexity through systematic parameter adjustment rather than complex mechanical mechanisms.
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 approach allows for effective focus adjustment and image capture of objects with difficult-to-focus front regions, enhancing the depth of field and perceived resolution by shifting the in-focus position towards the closest side during image capture.
Implementation Method 1
a sensor having a plurality of pixels, each of which photoelectrically converts light fluxes that have passed through different pupil regions of an optical system including a focus lens and output a pair of signals for focus detection
Data Source
AI summary
A method of an apparatus includes detecting a focusing state based on an output from a sensor, setting a step width of a focus position, and controlling to perform a plurality of times of image capturing based on a result of focus detection by the detecting and the set step width by the setting. In the setting, a step width from an in-focus position based on the result of focus detection by the detecting toward an infinity side is set to a value different from a step width from the in-focus position based on the result of focus detection by the detecting toward a closest side.