Multi-Focus Imaging for Extended Depth of Field With Less Processing
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Solution Overview
Problem
Existing methods for extending the depth of field in imaging systems increase software processing burden and photographing time, particularly when using multi-focus fusion techniques with deep learning algorithms.
Innovation Solution
A method and apparatus that determine a target focal length range based on an initial focal length using depth information images, obtained through a Time of Flight camera, to selectively capture and fuse images at specific focal lengths, reducing the need to process all focal lengths, thereby minimizing processing time and software burden.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a small-aperture lens is used to increase depth of field, then the depth of field is improved, but the image brightness decreases and noise increases
Solution Approach 1:
The patent divides the image acquisition process into multiple segments by capturing a series of images at different focus distances. Each image is sharp at a specific distance range, and through computational merging, the final image achieves extended depth of field without requiring a small aperture that would reduce brightness.
Solution Approach 2:
The patent transitions from a single-dimensional focus adjustment (aperture size) to a multi-dimensional approach by varying the focus distance across multiple images. This allows achieving extended depth of field through spatial diversification rather than relying solely on aperture reduction.
2Stability of the object's composition
If a small-aperture lens is used to increase depth of field, then the depth of field is improved, but the capture time increases due to need for multiple shots
Solution Approach 1:
The patent employs dynamic focus adjustment where the focus distance is systematically varied across multiple rapid captures. This dynamic approach allows the system to collect sufficient depth information quickly, and through efficient processing, produces the extended depth of field image faster than traditional small-aperture methods.
Solution Approach 2:
The patent performs preliminary capture of multiple focus-distance images in rapid succession before processing. By pre-acquiring all necessary focal plane data, the system enables subsequent processing to efficiently generate the final extended depth of field image without requiring extended capture time.
3Stability of the object's composition
If multiple images at different focus distances are captured and merged, then the depth of field is extended, but the device complexity increases
Solution Approach 1:
The patent makes the existing camera system multi-functional by enabling it to capture images at multiple focus distances using the same lens and sensor. Through software control of focus adjustment and automated merging algorithms, the system achieves extended depth of field capability without requiring additional specialized hardware components.
Solution Approach 2:
The patent introduces computational processing as an intermediary that bridges the gap between multiple captured images and the final extended depth of field image. This software-based mediator automatically performs the merging and focus composition tasks, reducing the need for complex manual intervention or additional hardware complexity.
Data Source
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AI summary
A method and an apparatus for obtaining an extended depth of field image, and an electronic device are disclosed. The method includes: determining a target focal length range based on an initial focal length (101), where the target focal length range includes the initial focal length; obtaining a plurality of images of a photographed object for a plurality of focal lengths in the target focal length range (102); and registering and fusing the plurality of images to obtain an extended depth of field image (103). The target focal length range of concern to a user is selected based on the initial focal length, so that there is no need to obtain images of all focal lengths of a lens, a quantity of obtained images and processing time of registration and fusion can be reduced.