Anamorphic Lens Autofocus via Directional Phase Detection
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Solution Overview
Problem
Anamorphic lenses with different optical characteristics in vertical and horizontal directions pose challenges for autofocus, as existing methods are inefficient due to requiring two-step operations with movable and focusing lenses, affecting autofocus speed and accuracy.
Innovation Solution
A signal processing device and method that performs detection processes separately in the vertical and horizontal directions of an anamorphic lens, using phase difference detection pixels with different placement densities and MTF characteristics to determine the in-focus position and control autofocus, allowing for efficient focus adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two lenses (movable lens and focusing lens) are used to achieve focusing with anamorphic lens, then focusing capability is improved, but autofocus speed deteriorates due to two-step operation
Solution Approach 1:
The invention extracts the focusing function from the movable lens and assigns it to a dedicated focusing lens. This separation allows the movable lens to handle only composition adjustment while the focusing lens handles exclusively focusing operations, enabling simultaneous independent control and eliminating the need for two-step operations.
Solution Approach 2:
The invention segments the lens system into functionally distinct components: a movable lens for composition adjustment and a focusing lens for focusing. This segmentation allows each lens to be optimized for its specific function and controlled independently, resolving the contradiction between achieving focusing capability and maintaining fast autofocus speed.
2Reliability
If two lenses (movable lens and focusing lens) are used to achieve focusing with anamorphic lens, then focusing capability is improved, but device complexity increases
Solution Approach 1:
The invention makes the lens barrel universal by equipping it with both a movable lens and a focusing lens, allowing it to perform multiple functions (composition adjustment and focusing) that would otherwise require separate optical systems. This multi-functionality approach manages complexity by integrating functions into a single lens barrel rather than using multiple separate optical systems.
3Extent of automation
If phase difference detection pixels are used for autofocus detection, then autofocus accuracy is improved, but detection precision deteriorates in anamorphic lens due to different focal lengths in vertical and horizontal directions
Solution Approach 1:
The invention applies local quality by using different placement densities of phase difference detection pixels in different directions. Specifically, pixels are arranged with higher density in the horizontal direction and lower density in the vertical direction, matching the anamorphic lens's optical characteristics where the horizontal direction has shorter focal length and requires finer sampling for accurate 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
Enables fast and accurate autofocus in image capture devices with anamorphic lenses by determining the in-focus position based on MTF characteristics and tilt information, improving focus adjustment efficiency and reducing the need for two-step lens operations.
Implementation Method 1
an image capture element provided with a plurality of phase difference detection pixels arranged to make placement densities different between a direction corresponding to a vertical direction of the anamorphic and a direction corresponding to a horizontal direction orthogonal to the vertical direction of the anamorphic lens
Implementation Method 2
An anamorphic lens is a lens that has different optical characteristics (focal length) in the vertical and horizontal directions
Implementation Method 3
determining the in-focus position based on MTF characteristics and tilt information
Data Source
AI summary
A signal processing device, on the basis of an image capture signal acquired by an image capture device provided with an anamorphic lens, performs a detection process each in a vertical direction of the anamorphic lens and in a horizontal direction of the anamorphic lens.