Dual-Optical-System Image Pickup With Averaged Defocus Detection
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Solution Overview
Problem
Existing image pickup apparatuses with dual optical systems face challenges in achieving high focus detecting accuracy due to reduced focus detecting areas and increased signal-to-noise ratio variations, particularly in stereoscopic imaging systems.
Innovation Solution
The apparatus includes an image sensor with pixels configured to receive light beams through different pupil partial areas, and a processor that calculates defocus amounts from paired signals to control the imaging optical system based on average defocus values from multiple focus detecting areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phase-difference AF is performed independently in each of two optical systems, then stereoscopic image capture is enabled, but focus detecting accuracy deteriorates due to reduced focus detecting area and increased S/N ratio variation
Solution Approach 1:
The patent merges the focus detection results from the first and second optical systems by calculating an average defocus amount. The processor acquires a first defocus amount from the first focus detecting area and a second defocus amount from the second focus detecting area, then computes their average to control the imaging optical system. This combining approach maintains stereoscopic capture capability while improving focus detection accuracy through aggregation of multiple measurements.
2Adaptability or versatility
If the focus detecting area is reduced to accommodate dual optical systems, then stereoscopic viewing is achieved, but signal-to-noise ratio deteriorates and focus detecting accuracy variation increases
Solution Approach 1:
The patent combines the defocus amount information from both optical systems to compensate for the reduced area in each individual system. By acquiring defocus amounts from both the first and second focus detecting areas and calculating their average, the system maintains reliable focus detection despite each individual area being smaller and having lower S/N ratio.
3Area of stationary object
If a lens unit with two optical systems is attached, then field of view is expanded for stereoscopic imaging, but focus detecting area for each optical system becomes half, reducing detection accuracy
Solution Approach 1:
The patent merges the focus detection capabilities of two separate optical systems that share the field of view. Each optical system captures light from different pupil partial areas, and the processor combines their defocus amount measurements to achieve accurate focus detection for the expanded field of view, effectively compensating for the reduced individual detecting areas.
Data Source
AI summary
An image pickup apparatus includes an image sensor having a plurality of pixels configured to receive light beams passing through a plurality of different pupil partial areas in an imaging optical system including a first optical system and a second optical system arranged in parallel with the first optical system, and a processor configured to acquire, based on a pair of signals from the plurality of pixels, a first defocus amount in a first focus detecting area at a first image height based on a first optical axis of the first optical system and a second defocus amount in a second focus detecting area at a second image height based on a second optical axis of the second optical system, and control the imaging optical system based on an average defocus amount of the first defocus amount and the second defocus amount.