Digital Light Path Length Modulation for Multi-Focal Image Capture
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Solution Overview
Problem
Existing image capture systems that provide multiple focal planes are either expensive, slow, and fragile due to mechanical movements or bulky and costly due to the use of multiple cameras, limiting the number of focal lengths that can be simultaneously captured.
Innovation Solution
An image capture system utilizing a modulation stack with digital light path length modulators, comprising optical path length extenders (OPLEs) and polarization modulators, which adjust light path lengths based on polarization to capture data at multiple focal distances, allowing for simultaneous capture of multiple focal lengths using a single camera system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mechanical movement mechanisms (gears or liquid lenses) are used to provide multiple focal planes, then multiple focal lengths can be captured, but the system becomes expensive, slow, and fragile
Solution Approach 1:
The patent replaces mechanical focus adjustment mechanisms (gears, liquid lenses) with a digital light field modulation system. A light field camera captures light rays from different directions and angles, and computational algorithms process this data to generate images at multiple focal planes. This eliminates moving parts entirely, making the system reliable and free from mechanical fragility while maintaining the capability to capture multiple focal lengths.
Solution Approach 2:
The patent changes the approach from mechanically altering optical parameters (focal length) to capturing a comprehensive light field dataset and computationally adjusting focus parameters. By capturing light intensity, direction, and angle information simultaneously, the system can digitally refocus at multiple planes without physical parameter changes, eliminating mechanical complexity and improving reliability.
2Adaptability or versatility
If mechanical movement mechanisms (gears or liquid lenses) are used to provide multiple focal planes, then multiple focal lengths can be captured, but the system becomes slow
Solution Approach 1:
The patent performs preliminary action by capturing the complete light field information (all light rays from different directions and angles) in a single exposure. This comprehensive data capture allows instantaneous computational refocusing at any desired focal plane without waiting for mechanical adjustments. The focus adjustment speed becomes limited only by processing capability, not mechanical response time, dramatically improving speed.
3Adaptability or versatility
If multiple cameras are used to capture multiple focal lengths, then multiple focal lengths can be simultaneously captured, but the system becomes bulky and expensive
Solution Approach 1:
The patent makes a single camera system universal by enabling it to perform multiple focal length capture functions that would otherwise require multiple specialized cameras. The light field camera captures directional and angular information in addition to intensity, allowing one camera to computationally generate multiple focal planes. This eliminates the need for multiple physical cameras, reducing system bulk while maintaining the multi-focal capability.
4Adaptability or versatility
If multiple cameras are used to capture multiple focal lengths, then multiple focal lengths can be simultaneously captured, but the system becomes expensive
Solution Approach 1:
The patent merges the functions of multiple cameras into a single light field camera system. Instead of using separate cameras for different focal lengths, the system combines light capture from multiple directions and angles into one sensor array, then uses computational methods to separate and focus the data at different planes. This merging reduces component count, manufacturing complexity, and overall system cost while achieving the same multi-focal capability.
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 efficient and cost-effective capture of multiple focal distances without mechanical movement, reducing bulk and expense, and allowing for the simultaneous capture of multiple focal lengths, enhancing the capability of image capture systems.
Implementation Method 1
Each digital light path length modulator includes an optical path length extender (OPLE) and a polarization modulator, and can be used to adjust the path length of light. In one embodiment, light with state 1 polarization travels through a longer path in the OPLE than light with state 2 polarization.
Data Source
AI summary
An image capture system comprising an optical path length extender (OPLE) to direct the light having a first polarization through a first light path through the OPLE, and to direct the light having a second polarization through a second light path through the OPLE, the first and second light paths having different light path lengths. The image capture system further comprising an image sensor to capture a plurality of image portions at a plurality of focal distances.