Image Pickup Apparatus Control Mode Selection for Multi-Object Focusing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image pickup apparatuses face challenges in achieving high-speed and high-accuracy focusing on multiple objects due to temporary loss of focus during contrast evaluation-based control and inaccuracies in defocus amount detection using the image pickup plane phase difference method.
Innovation Solution
The image pickup apparatus employs a control method that selects an optimum focus control mode based on defocus information and its reliability, switching between focus mode, tilt mode, focus-tilt calculation mode, and focus maintenance tilt mode to ensure rapid and accurate focusing on multiple objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If contrast evaluation-based control is used to detect in-focus positions, then focusing can be performed on multiple objects, but the object may temporarily become out of focus during the detection process and the in-focus state takes time to be acquired
Solution Approach 1:
The patent replaces contrast evaluation-based focus detection with image pickup plane phase difference method. This substitution enables immediate detection of defocus amounts for multiple objects, allowing the system to calculate and execute focus and tilt control without temporary focus loss, thereby reducing the time to acquire in-focus state while maintaining the ability to focus on multiple objects
Solution Approach 2:
The patent introduces defocus amount detection as an intermediary step that provides accurate focus information for multiple objects simultaneously. This intermediary detection mechanism enables the control unit to determine appropriate focus positions and tilt control amounts without the iterative contrast evaluation process, thus reducing focus acquisition time while maintaining multi-object focusing capability
2Speed
If image pickup plane phase difference method is used to detect defocus amount, then faster focusing is expected, but highly accurate defocus amount is not always detected
Solution Approach 1:
The patent dynamically switches between different control modes (focus mode, tilt mode, focus-tilt calculation mode) based on the detected defocus information and its reliability. When phase difference method provides reliable defocus amounts, the system uses focus-tilt calculation mode for high-speed focusing. When accuracy is insufficient, it transitions to contrast evaluation-based modes, thereby maintaining both speed and precision adaptively
Solution Approach 2:
The patent changes the control parameter selection based on defocus information reliability. By monitoring the quality of defocus amount detection and adjusting the control mode accordingly, the system optimizes the balance between focusing speed and defocus detection accuracy, using phase difference method when reliable and contrast evaluation when higher precision is needed
3Adaptability or versatility
If multiple control modes are implemented to handle different focusing scenarios, then focusing flexibility is improved, but control system complexity increases
Solution Approach 1:
The patent segments the focusing control into distinct modes (focus mode, tilt mode, focus-tilt calculation mode) with clearly defined selection criteria. Each mode handles specific focusing scenarios, and the control unit selects the appropriate mode based on defocus information reliability. This segmentation provides flexibility while managing complexity through structured decision-making
Solution Approach 2:
The patent implements dynamic mode switching based on real-time defocus information quality. The control system adapts its complexity by selecting the simplest adequate control mode for each situation, using sophisticated focus-tilt calculation when phase difference data is reliable and simpler contrast-based control when it is not, thereby balancing flexibility and complexity
Data Source
Figure 1
Figure 2~3D
Figure 4
AI summary
An image pickup apparatus includes a tilt driving unit configured to change a tilt of at least one of an image sensor and an image pickup optical system so as to change an angle between an image pickup plane of the image sensor and a principal plane of the image pickup optical system, a focus driving unit configured to drive a focus lens of the image pickup optical system, an area setting unit configured to set a plurality of areas in a captured image, a defocus information detection unit configured to detect defocus information for each of the plurality of areas, and a control unit configured to select one control mode from a plurality of control modes based on the defocus information on each of the plurality of areas, the plurality of control modes being used for performing focusing control using at least one of the tilt driving unit and the focus driving unit.