Rolling Shutter Adaptive Optical Plane Formation
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Solution Overview
Problem
Traditional photography and digital imaging systems face challenges in achieving a wide depth of field due to field curvature and Petzval surface aberrations, which result in objects being out of focus unless precisely aligned with the optical axis, limiting the depth of field to a single focal point.
Innovation Solution
The method involves manipulating the optical relationship between the lens and image sensing surface by varying the effective image distance for different portions of the image sensing surface within a single exposure frame, using a rolling shutter mechanism to adapt exposure times based on object distance, brightness, and movement, and synchronizing this with lens movement or voltage changes to correct field curvature and enhance depth of field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed focusing lens is used to precisely focus on an object at a specific distance, then the object is in sharp focus, but other objects at different distances are out of focus, limiting the depth of field
Solution Approach 1:
The patent applies dynamics by making the image sensing surface movable relative to the lens along the optical axis. Different portions of the sensing surface are positioned at different image distances during a single exposure, allowing each portion to capture objects at different object distances in focus. This dynamic adjustment enables the system to achieve extended depth of field while maintaining focus precision for multiple objects at varying distances.
2Adaptability or versatility
If the image sensing surface is tilted to increase depth of field coverage, then a range of distances can be captured, but field curvature and Petzval surface aberrations cause objects to be out of focus
Solution Approach 1:
The patent applies local quality by assigning different image distances to different portions of the image sensing surface. Each portion is optimally positioned for its specific region of interest, with nearer portions focused on closer objects and farther portions focused on distant objects. This localized optimization allows the system to maintain focus accuracy across the entire scene while achieving extended depth of field coverage, avoiding the field curvature issues associated with tilted surfaces.
3Adaptability or versatility
If multiple photos are taken at different focal points and overlaid to increase depth of field, then more objects can be in focus, but the process is time-consuming and complex
Solution Approach 1:
The patent applies segmentation by dividing the image sensing surface into multiple portions, each responsible for capturing objects at specific distance ranges. During a single exposure, different portions simultaneously record in-focus images of objects at different distances. This spatial segmentation eliminates the need for multiple sequential photos and complex overlay processing, achieving extended depth of field in real-time while reducing imaging time.
4Measurement precision
If the lens or sensor is moved to focus on objects at different distances, then focus can be adjusted, but only one distance can be focused at a time
Solution Approach 1:
The patent applies dimensionality change by transitioning from a single image distance to multiple image distances simultaneously. Instead of moving the entire sensing surface to focus on one distance at a time, the system positions different portions of the sensing surface at different image distances along the optical axis. This creates a depth dimension in the image plane, allowing simultaneous focus adjustment for multiple distances and achieving multi-distance capability while maintaining focus precision.
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 approach extends the depth of field by allowing multiple objects at different distances to be in focus within a single image, correcting field curvature and maintaining image quality across varying distances and lighting conditions, while avoiding the need for complex lens arrangements.
Implementation Method 1
exposing different portions of the image sensing surface synchronous with manipulating the optical relationship
Implementation Method 2
manipulating an optical relationship between an optical lens and an image sensing surface
Implementation Method 3
The lens is assumed thin for certain assumptions. The focal length f of the lens 20 is that distance behind the lens where parallel light rays entering the lens are focused
Data Source
AI summary
A scene is imaged by moving an optical lens relative to an image sensing surface (such as film or a pixel array) synchronously with exposing different portions of the image sensing surface. The synchronous actions are preferably adaptable to the scene being imaged, so objects at different object distances are focused at different times and exposed to different portions of the sensing surface at different times within an exposure frame period. Exposure time for the different portions of the sensor may be varied according to speed or brightness of the different objects in the scene to be imaged, as detected at the camera by measuring apparatus similar to auto focus distance measuring apparatus. A camera and a program of computer readable instructions are also detailed. Alternatives to moving the lens relative to the image sensing surface include changing a shape of the lens.