Image Magnification Correction for Interchangeable Lens Cameras
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Solution Overview
Problem
Existing image capturing apparatuses face significant variations in image magnification due to changes in focal length of focus lenses, particularly during autofocus and zoom operations, leading to decreased moving image quality and unstable focus driving speeds.
Innovation Solution
An image capturing apparatus with a focus lens system that includes a detection unit for focal point state, a calculation unit for image plane speed and focus lens driving direction, and a control unit for adjusting focus lens driving based on focal length variation rates, allowing for angle-of-view correction through image resizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If focus lens driving speed is increased to improve autofocus performance, then focus response time is improved, but variation in angle of view becomes more noticeable
Solution Approach 1:
The patent converts the harmful effect of focal length variation during focus driving into a beneficial correction by calculating the magnification variation and applying reverse correction through image scaling. The system measures the angle of view variation caused by focus lens movement and compensates for it by scaling the captured image, thereby transforming the problem into a solution.
Solution Approach 2:
The patent changes the image magnification parameter based on the detected focal length variation. By dynamically adjusting the image scaling factor according to the focus lens position and focal length changes, the system maintains constant angle of view despite focus driving operations.
2Measurement precision
If focus driving is performed to maintain in-focus state during subject distance change, then focus accuracy is improved, but variation in angle of view becomes noticeable
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the focal length of the focus lens and calculates the resulting magnification variation. Based on this feedback, the system dynamically adjusts the image scaling factor to compensate for angle of view changes, thereby maintaining consistent composition during focus adjustments.
Solution Approach 2:
The system converts the harmful angle of view variation during focus driving into a correctable parameter by calculating the magnification ratio and applying inverse scaling to the captured image, thereby maintaining composition stability.
3Stability of the object's composition
If conventional angle of view correction techniques are applied, then angle of view stability is improved, but the solution is limited to lens-combined cameras and does not work with interchangeable lenses
Solution Approach 1:
The patent creates a universal angle of view correction system that works with both lens-combined cameras and interchangeable lens systems. By placing the correction functionality in the camera body rather than the lens, the system achieves multi-functionality and broad compatibility across different lens types and mounting systems.
Solution Approach 2:
The patent introduces an intermediary correction mechanism in the camera body that mediates between the focus lens and the image sensor. This intermediary system calculates and applies magnification correction based on focus lens position information, enabling angle of view stabilization regardless of the specific lens attachment.
4Stability of the object's composition
If magnification variation value is used to limit focus lens driving, then angle of view variation is reduced, but focus lens driving speed decreases and maximum focal length information becomes unavailable
Solution Approach 1:
The patent replaces mechanical limitation of focus lens driving with a digital/image processing solution. Instead of physically restricting focus lens movement through mechanical means, the system calculates magnification variation and applies software-based image scaling to achieve angle of view correction, thereby maintaining full focus driving speed and range.
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 solution effectively corrects variations in image magnification, enhancing moving image quality by stabilizing focus driving speeds and maintaining consistent angle of view, even with various lens attachments.
Implementation Method 1
an image sensor configured to photoelectrically convert light received via the lens apparatus
Data Source
AI summary
A lens apparatus including a focus lens is attachable to and detachable from an image capturing apparatus. An image sensor photoelectrically converts an optical image formed through the lens apparatus. An image generation unit generates an image based on an image signal output from the image capturing apparatus. An image magnification variation correction control unit receives information about a variation in focal length from the lens apparatus by a lens communication control unit configured to control communication with the lens apparatus, and the image magnification variation correction control unit corrects a magnification of the image based on the received information.