Phase-Difference Pixel Readout Order for Tilt Shooting Accuracy
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Solution Overview
Problem
During tilt shooting with a camera using a telephoto lens, the sensitivity difference between phase-difference detection pixels in a solid-state image sensor leads to decreased accuracy of ranging and slower focusing speeds due to varying sensitivity of photoelectric conversion units based on the tilt angle.
Innovation Solution
The image capturing apparatus includes a driving mechanism to change the angle of the image plane relative to the optical system and a readout unit that adjusts the order of signal reading from first and second conversion units based on the tilt angle, ensuring that the pixel signal from the photoelectric conversion unit with lower sensitivity is read out first to maintain accurate focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If tilt shooting is performed with phase-difference detection pixels, then the in-focus range can be expanded, but the sensitivity difference between photoelectric conversion units decreases ranging accuracy and slows focusing speed
Solution Approach 1:
The patent applies dynamics by making the readout order adaptive rather than fixed. The control unit dynamically determines the readout sequence based on the tilt angle detected during shooting, switching between different readout orders to optimize performance for each specific tilt condition, thereby maintaining ranging accuracy across varying tilt angles
Solution Approach 2:
The patent changes the readout order parameter based on the tilt angle. By detecting the tilt angle and selecting different readout sequences (first readout order for smaller tilt angles, second readout order for larger tilt angles), the system adapts to varying optical conditions to maintain measurement precision while preserving the expanded in-focus range benefit of tilt shooting
2Area of stationary object
If tilt shooting is performed with phase-difference detection pixels, then the in-focus range can be expanded, but the focusing speed decreases due to sensitivity variations
Solution Approach 1:
The system dynamically adjusts the readout sequence based on real-time tilt angle detection. By switching between different readout orders adapted to specific tilt conditions, the system optimizes signal processing efficiency and maintains focusing speed despite the complexity of tilt shooting with phase-difference detection pixels
Solution Approach 2:
The readout order parameter is changed based on tilt angle magnitude. For smaller tilt angles, one readout order is used; for larger tilt angles, a different readout order is selected. This parameter adaptation optimizes the balance between utilizing the expanded in-focus range and maintaining efficient focusing speed
3Device complexity
If signals are read out in a fixed order from phase-difference detection pixels, then the readout process is simple, but ranging accuracy decreases due to sensitivity differences at various tilt angles
Solution Approach 1:
Rather than using a single fixed readout order, the patent implements a dynamic selection mechanism that chooses between multiple readout orders based on the detected tilt angle. This dynamic approach maintains relatively simple readout processes for each specific condition while achieving high ranging accuracy across a wide range of tilt angles
Solution Approach 2:
The readout order parameter is changed according to the tilt angle magnitude. The control unit detects the tilt angle and selects the appropriate readout order (first or second) to optimize ranging accuracy for each specific shooting condition, balancing complexity and precision
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 suppresses the decrease in ranging accuracy and improves focusing speed by optimizing the readout order of pixel signals from phase-difference detection pixels, maintaining image focus over a wider range despite tilt angle variations.
Implementation Method 1
a first conversion unit and a second conversion unit for performing phase-difference AF
Data Source
AI summary
An apparatus is provided with a sensor including a plurality of pixels that are arrayed two-dimensionally, at least a part of the plurality of pixels being a phase-difference detection pixel that include a first conversion unit and a second conversion unit for performing phase-difference AF. A driving mechanism changes an angle of an image plane of the sensor relative to a main plane of an optical system. A readout unit reads out signals obtained in the first conversion unit and the second conversion unit in an order corresponding to the angle.