Camera Array POV Alignment via Spherical Lens Optics
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Solution Overview
Problem
Conventional head-mounted displays (HMDs) for virtual and mixed reality systems have scene cameras with an entrance pupil and point of view (POV) offset from the user's eyes, leading to an inaccurate representation of the environment.
Innovation Solution
The implementation of two-dimensional arrays of small form factor cameras positioned along a spherical curve, with the entrance pupils aligned at or near the user's eyes, and optimized optics to capture images from the same perspective as the user's eyes, using a combination of lens groups and aperture stops to correct the POV and reduce the number of cameras and pixels needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional scene cameras are mounted at the front of the HMD, then the camera structure is simple and easy to manufacture, but the point of view of the cameras is offset from the user's eyes leading to inaccurate environmental representation
Solution Approach 1:
The camera system is divided into multiple small form factor cameras arranged in arrays for each eye, with each camera capturing a specific portion of the scene. This segmentation allows the entrance pupils to be positioned at or near the user's eyes while distributing the total field of view across multiple camera units, resolving the contradiction between POV accuracy and system complexity.
Solution Approach 2:
The cameras are positioned along a spherical curve rather than on a flat plane, adding a curved spatial dimension to the camera array configuration. This spherical arrangement enables the entrance pupils to align with the user's eyes while maintaining compact form factor, addressing the contradiction between accurate POV representation and device complexity.
2Measurement precision
If two-dimensional arrays of small form factor cameras are used to capture wide field of view, then the point of view accuracy is improved, but the number of cameras and pixels required increases
Solution Approach 1:
Multiple small form factor cameras are merged into two-dimensional arrays for each eye, with their fields of view combining to capture the complete scene. This merging approach achieves wide field of view and accurate POV representation while using smaller individual camera units, resolving the contradiction between POV accuracy and quantity of cameras.
Solution Approach 2:
Each small form factor camera in the array is optimized for its specific local field of view portion, with entrance pupils positioned to capture light from specific angular ranges. This local optimization allows the entire array to achieve wide field of view and accurate POV without requiring excessive pixels per camera, addressing the contradiction between POV accuracy and total pixel count.
3Measurement precision
If the entrance pupils of the cameras are positioned behind the image planes, then the point of view is aligned with the user's eyes, but the optical design becomes more complex
Solution Approach 1:
The camera optics are designed with the entrance pupil positioned behind the image plane, creating a curved optical path that aligns the POV with the user's eyes. This curved optical configuration, combined with the spherical arrangement of cameras, achieves accurate POV alignment while maintaining manufacturability through standardized optical elements adapted to the curved geometry.
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 configuration provides a more accurate and immersive experience by aligning the camera perspective with the user's, allowing for a wider field of view with fewer cameras and pixels, while reducing vignetting and simplifying the connection of camera arrays to the processing system.
Implementation Method 1
a first lens group including one or more lens elements; an aperture stop; a second lens group including one or more lens elements
Data Source
AI summary
A device for MR/VR systems that includes a two-dimensional array of cameras that capture images of respective portions of a scene. The cameras are positioned along a spherical surface so that the cameras have adjacent fields of view. The entrance pupils of the cameras are positioned at or near the user's eye while the cameras also form optimized images at the sensor. Methods for reducing the number of cameras in an array, as well as methods for reducing the number of pixels read from the array and processed by the pipeline, are also described.