Camera Focus Adjustment Optical System Shifting Limit
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Solution Overview
Problem
Existing camera systems face challenges in maintaining accurate focus adjustment when photographic conditions change during image capture, particularly when the focus detection region shifts or when a subject moves, leading to potential misfocus on the intended subject.
Innovation Solution
A camera system comprising an image capturing unit, a detection unit, a control unit, and an acquisition unit that continuously adjusts the focus based on detected in-focus positions, subject information, and movement data, using a phase detection method to calculate defocusing amounts and adjust the focus adjustment optical system accordingly, with adjustable threshold values based on subject magnification ratio and focus detection region size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous focus adjustment is performed based on detected in-focus positions, then focus tracking capability is improved, but focus accuracy deteriorates when photographic conditions change
Solution Approach 1:
The patent applies dynamics by making the focus adjustment period variable rather than fixed. The control unit dynamically adjusts the focus adjustment period based on subject movement information and defocusing amount thresholds. When the subject is stationary or moves slowly, a shorter focus adjustment period enables continuous tracking. When the subject moves rapidly or conditions change, the period is extended to prevent erroneous focus adjustments, thus resolving the contradiction between continuous tracking and focus accuracy.
Solution Approach 2:
The patent changes the parameter of focus adjustment period based on detected subject movement and defocusing amounts. By adjusting this temporal parameter dynamically, the system adapts its focus adjustment frequency to match actual shooting conditions, enabling continuous tracking when appropriate while maintaining accuracy when conditions change.
2Speed
If focus adjustment is performed frequently to track moving subjects, then focus tracking speed is improved, but focus stability deteriorates due to potential misfocus on foreign objects
Solution Approach 1:
The patent implements feedback by using detected subject movement information and defocusing amounts to control focus adjustment timing. The system continuously monitors subject movement and defocusing status, then adjusts the focus adjustment period accordingly. This feedback mechanism enables rapid focus tracking when subjects move while preventing unstable focus adjustments when foreign objects enter the frame, as the system can detect the abnormal defocusing patterns and extend the adjustment period.
Solution Approach 2:
By dynamically adjusting the focus adjustment period based on real-time detection of subject movement and defocusing amounts, the system speeds up focus response when needed while maintaining stability by extending the period when foreign objects are detected through abnormal defocusing patterns.
3Ease of operation
If a fixed threshold value is used for focus adjustment, then control simplicity is improved, but adaptability to different shooting conditions deteriorates
Solution Approach 1:
The patent transforms the static threshold value into a dynamic parameter that adapts to different shooting conditions. The control unit sets different defocusing amount thresholds based on detected subject movement information - using smaller thresholds for stationary subjects and larger thresholds for moving subjects. This dynamic threshold adjustment maintains control simplicity while achieving high adaptability across various photographic scenarios.
Solution Approach 2:
The patent changes the threshold parameter based on shooting conditions detected through subject movement analysis. By adjusting the defocusing amount threshold according to whether the subject is stationary or moving, the system maintains simple control logic while achieving versatile adaptation to different photographic scenarios.
4Area of stationary object
If the focus detection region is enlarged to capture moving subjects, then subject coverage is improved, but focus detection precision deteriorates
Solution Approach 1:
The patent applies dynamics by adjusting the focus adjustment period based on the size of the focus detection region. When a larger region is used to capture moving subjects, the system extends the focus adjustment period to maintain detection precision. This dynamic adjustment compensates for the reduced precision inherent in larger detection regions by reducing the frequency of adjustments, thereby maintaining overall focus accuracy while preserving subject coverage.
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 continuous focus tracking on the intended subject, preventing focus adjustment on foreign objects and maintaining accurate focus despite changes in photographic conditions or subject movement, by dynamically adjusting threshold values and focus adjustment periods.
Implementation Method 1
an image capturing unit that outputs a signal by capturing a subject image via an optical system having a focus adjustment optical system
Data Source
AI summary
A camera includes: an image capturing unit that outputs a signal by capturing a subject image via an optical system having a focus adjustment optical system; a detection unit that detects an in-focus position at which the subject image is in focus on the image capturing unit by the optical system based on the signal outputted from the image capturing unit; a control unit that controls a position of the focus adjustment optical system so as to focus continuously upon a specified subject based on the in-focus position detected by the detection unit; and an acquisition unit that acquires information related to at least one of a distance to the specified subject, a size of the specified subject, and the optical system; wherein the control unit controls the position of the focus adjustment optical system based on the information acquired by the acquisition unit.