Folded Optic Camera Array Eliminates Parallax Artifacts
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Solution Overview
Problem
Conventional array cameras face quality degradation due to parallax and tilt artifacts when stitching images from multiple cameras, leading to incomplete or distorted images, especially when overlapping fields of view are involved.
Innovation Solution
The implementation of a folded optic sensor array system with a central mirror or prism that splits incoming light into multiple portions, where each camera captures a portion of the image without overlap, and a processor performs projective transforms to correct tilt artifacts, ensuring all cameras appear to capture images from a virtual center of projection, thereby eliminating parallax and tilt issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a multi-camera array is used to capture images from different angles, then the field of view and coverage are improved, but parallax artifacts and image stitching quality deteriorate
Solution Approach 1:
The image capture system is divided into multiple independent camera units, each capturing a specific portion of the target image. The central mirror is segmented into multiple facets, with each facet directing light to a corresponding sensor. This segmentation allows each camera to capture images from slightly different angles while maintaining overall system coherence through the virtual center of projection geometry.
Solution Approach 2:
A central mirror with multiple facets acts as an intermediary element that redirects light from the target image to multiple sensors. The mirror facets are positioned and angled to direct light portions to corresponding sensors, enabling the system to capture images from different angles while maintaining a virtual center of projection, thus reducing parallax artifacts.
2Length of moving object
If cameras are positioned close together to maintain a low-profile device, then device thickness is reduced, but parallax between cameras increases
Solution Approach 1:
The system uses a central mirror positioned above the sensors to redirect light paths in a vertical dimension. This allows cameras to be positioned close together horizontally (maintaining low profile) while the mirror facets angle light from different horizontal positions to each sensor, creating effective baseline separation without increasing device thickness.
Solution Approach 2:
The central mirror creates virtual images of the target scene for each sensor, effectively copying the target image multiple times with different viewing angles. Each sensor receives a copied version of the target image redirected by a specific mirror facet, allowing parallax capture without physical camera separation.
3Stability of the object's composition
If overlapping fields of view are used between cameras, then seamless stitching is enabled, but parallax causes ghosting and double images
Solution Approach 1:
The system carefully controls the angular parameters of each camera and mirror facet orientation to create overlapping fields of view with minimal parallax displacement. By adjusting the mirror facet angles and camera positions, the system maintains geometric consistency across overlapping regions, preventing ghosting while enabling seamless stitching.
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 enables the creation of low-profile imaging systems with high-quality images free from parallax and tilt artifacts, allowing seamless stitching of images without ghosting or discontinuous features, maintaining focal length and resolution across the sensor array's field of view.
Implementation Method 1
a mirror located with respect to the lens assembly to provide light to the lens assembly, the mirror further positioned on (or within) a mirror plane
Implementation Method 2
a lens assembly including at least one lens, the lens assembly having a center of projection, the lens assembly positioned to focus light on the image sensor
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Aspects relate to an array camera exhibiting little or no parallax artifacts in captured images. For example, the planes of the central mirror surfaces of the array camera can be located at a midpoint along, and orthogonally to, a line between the corresponding camera location and the virtual camera location. Accordingly, the cones of all of the cameras in the array appear as if coming from the virtual camera location after folding by the mirrors. Each sensor in the array "sees" a portion of the image scene using a corresponding facet of the central mirror prism, and accordingly each individual sensor/mirror pair represents only a sub-aperture of the total array camera. The complete array camera has a synthetic aperture generated based on the sum of all individual aperture rays.