Focusing Adjustment Apparatus Correcting Optical Aberrations
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Solution Overview
Problem
Conventional imaging apparatuses face challenges in accurately correcting focus detection errors due to optical system aberrations, particularly in contrast autofocus and phase difference autofocus methods, which fail to adequately align the focusing state sensed by the observer with the captured image.
Innovation Solution
A focusing adjustment apparatus that includes a focusing unit, information acquisition units for signal characteristics and captured image characteristics, and a control unit to calculate correction values based on these inputs, adjusting the focusing signal to improve focus detection precision by aligning the focusing state with the captured image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional focus detection methods (contrast AF or phase difference AF) are used, then focusing operation can be performed, but focus detection error occurs due to optical system aberrations
Solution Approach 1:
The patent implements feedback by using the image sensor to detect the actual focusing state of captured images and comparing it with the focusing state indicated by the focus detection result. This feedback loop enables calculation of correction values that compensate for focus detection errors, thereby improving the alignment between detected focusing state and actual captured image.
Solution Approach 2:
The patent changes parameters by calculating correction values based on evaluation bands and applying them to adjust the focus detection result. The correction value modifies the focusing operation parameter to compensate for optical system aberrations, transforming the inaccurate focus detection result into an accurate one that aligns with the actual captured image.
2Measurement precision
If correction value calculation based on evaluation band is applied, then some focus detection error correction is achieved, but sufficient correction of focus detection error cannot be accomplished
Solution Approach 1:
The patent enhances feedback by directly using the image sensor to detect the actual focusing state from captured images and comparing it with the focus detection result. This closed-loop feedback mechanism enables more accurate calculation of correction values that sufficiently correct focus detection errors, achieving better alignment between detected and actual focusing states.
Solution Approach 2:
The patent substitutes the conventional mechanical/optical focus detection mechanism with an image-based detection approach. Instead of relying solely on contrast or phase difference signals, the system uses the image sensor to directly detect the focusing state from captured images, replacing the traditional detection mechanism and enabling more accurate error correction.
3Ease of operation
If focus detection result is used directly without correction, then focusing operation is simple, but focus detection error remains due to optical aberrations
Solution Approach 1:
The patent implements self-service by enabling the imaging apparatus to automatically detect its own focusing state using the image sensor and automatically calculate correction values to compensate for its own optical system aberrations. The system performs self-diagnosis and self-correction, maintaining ease of operation while improving focus detection accuracy through automated correction processes.
Solution Approach 2:
The patent automatically changes parameters by calculating and applying correction values to the focus detection result. This parameter adjustment compensates for optical aberrations without requiring manual intervention, maintaining operational simplicity while significantly improving focus detection accuracy through automated parameter modification.
Data Source
AI summary
A focusing adjustment apparatus includes a focusing unit, a first acquisition unit, a second acquisition unit, and a control unit. The focusing unit outputs a first signal for a focusing operation. The first acquisition unit acquires first information, which is related to characteristics of a signal used for outputting the first signal, and second information, which is related to characteristics of a captured image and is predetermined. The second acquisition unit acquires third information on aberrations of an imaging optical system. The control unit calculates a correction value based on the first information, the second information, and the third information. By using the correction value, the control unit changes the first signal, output from the focusing unit, to a second signal used in the focusing operation.