Dual-Camera Focus Control Using Telephoto Defocus Signals
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Solution Overview
Problem
Phase pixels that exclusively output phase difference signals do not contribute to image generation, leading to image quality degradation and difficulty in focusing on small subjects, especially in wide-angle images, due to increased noise and inaccurate defocus information.
Innovation Solution
A dual-camera system with a first camera unit for wide-angle imaging and a second camera unit for telephoto imaging, where the second camera unit provides defocus information for accurate focus control of the first camera unit by referencing phase difference signals from its phase pixels, ensuring discrete arrangement of phase pixels to minimize noise and improve focus accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase pixels are arranged densely to improve focus detection capability, then focus detection precision is improved, but image quality deteriorates due to increased noise and pixel interpolation requirements
Solution Approach 1:
The photographing element is segmented into distinct functional regions: a first region with phase pixels for focus detection and a second region with ordinary pixels for image generation. This spatial segmentation allows each region to specialize in its function without interference, eliminating the need for pixel interpolation and reducing image noise while maintaining focus detection precision
Solution Approach 2:
Phase pixels are extracted and concentrated into a dedicated first region, separate from the ordinary pixels in the second region. This extraction eliminates the harmful effect of phase pixels on image quality while preserving their focus detection function, as the phase pixels no longer need to be interpolated into the final image
2Extent of automation
If phase pixels are used for focus detection, then autofocus capability is improved, but image generation quality deteriorates due to missing pixel data
Solution Approach 1:
The photographing element is divided into a first region for phase detection and a second region for image capture. This segmentation allows the phase pixels to exclusively perform autofocus detection without compromising image quality, as the ordinary pixels in the second region provide complete pixel data for image generation
Solution Approach 2:
The dual-region photographing element provides multi-functionality: the first region specializes in phase difference detection for autofocus, while the second region specializes in high-quality image capture. Both functions operate simultaneously without interfering with each other, achieving universal performance in both autofocus and image generation
3Device complexity
If a single camera unit is used, then device complexity is reduced, but focus control accuracy deteriorates in wide-angle imaging scenarios
Solution Approach 1:
The patent combines a first camera unit with a second camera unit into a single photographing device. The second camera unit's phase difference information is used to assist focus control in the first camera unit, particularly for wide-angle imaging. This merging improves focus control accuracy without significantly increasing overall device complexity, as the systems work cooperatively
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 accurate and automatic focusing on main subjects in wide-angle images by leveraging defocus information from the second camera unit, reducing noise and enhancing focus precision, even in scenes with high-frequency backgrounds.
Implementation Method 1
a photographing element, and the photographing element includes a two-dimensional arrangement of ordinary pixels that output an image signal for generating an image and phase pixels that are surrounded by the ordinary pixels and arranged discretely and output a phase difference signal for detecting a focus
Data Source
AI summary
A photographing device is provided, including a first camera unit having a first optical system; a second camera unit having a second optical system facing a same direction as the first camera unit; and a focus control component performing focus control over the first camera unit and the second camera unit. Each of the first camera unit and the second camera unit includes a photographing element, and the photographing element includes a two-dimensional arrangement of ordinary pixels that output an image signal for generating an image and phase pixels that are surrounded by the ordinary pixels and arranged discretely and output a phase difference signal for detecting a focus. The focus control component performs focus control over the first optical system with reference to second defocus information acquired from the phase difference signal output by the photographing element of the second camera unit, in case that the image is generated using the image signal output by the photographing element of the first camera unit.