Rapid Synchronized Lighting and Shuttering for Ambient Light Rejection
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Solution Overview
Problem
Current imaging techniques inadequately address undesired ambient light, often requiring high power usage, complex processing, or failing to handle changing light conditions, especially in bright environments, leading to motion artifacts.
Innovation Solution
The implementation of rapid synchronized lighting and shuttering techniques using two image sensors and a light source that flashes rapidly, allowing one sensor to capture images when illuminated and the other when not, thereby reducing or eliminating motion artifacts, even with slow and low-cost cameras.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a very bright light is used to drown out ambient light, then ambient light suppression is improved, but power consumption increases and heat generation increases
Solution Approach 1:
The light source is activated in periodic flashes synchronized with the image sensor's exposure cycles. By flashing the light source at the same rate as the sensor captures images, the system separates ambient light suppression from continuous high-power illumination, achieving effective ambient rejection while dramatically reducing average power consumption and heat generation.
2Object-affected harmful factors
If a very bright light is used to drown out ambient light, then ambient light suppression is improved, but heat generation increases
Solution Approach 1:
The light source operates as a periodic flasher synchronized with image capture cycles rather than providing continuous illumination. This periodic operation reduces the cumulative energy input to the scene, thereby minimizing heat generation while maintaining effective ambient light suppression during each exposure cycle.
3Object-affected harmful factors
If spectral approaches with narrow-frequency lighting are used, then ambient light filtering is improved, but the lighting device may drift out of the narrow-frequency band
Solution Approach 1:
Instead of relying on the lighting device to maintain a narrow frequency band, the system extracts and removes ambient light through temporal separation. By capturing images during and outside of the light flash periods and subtracting the ambient component, the system eliminates the need for precise frequency control, making the approach more reliable against frequency drift.
4Object-affected harmful factors
If complex processing and fast cameras are used to address motion artifacts, then motion artifact reduction is improved, but computational cost increases and device size increases
Solution Approach 1:
The system performs preliminary action by capturing a reference image during ambient light exposure before the actual measurement. This pre-captured ambient reference is then subtracted from subsequent images, eliminating the need for complex real-time processing and fast cameras, thereby reducing computational cost and device complexity while maintaining motion artifact reduction.
5Object-affected harmful factors
If sequential image capture with light on and light off is used, then ambient light separation is improved, but temporal resolution decreases and motion artifacts increase
Solution Approach 1:
The light source flashes at a frequency synchronized with the image sensor's exposure rate, creating periodic illumination cycles. This synchronization allows the system to capture multiple images at high temporal resolution during each flash cycle, maintaining fast temporal response while achieving effective ambient light separation through the periodic on/off pattern.
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 effectively subtracts ambient light with minimal motion artifacts, using relatively slow image sensors and low computational resources, achieving resilience to motion similar to fast frame-rate systems at lower costs.
Implementation Method 1
a light source that rapidly illuminates an image area
Implementation Method 2
one image sensor to receive light from the image area when the image area is illuminated
Data Source
AI summary
This document describes various apparatuses and techniques for rapid synchronized lighting and shuttering. These apparatuses and techniques are capable of capturing two images, where one of the images integrates multiple exposures during which an image area is illuminated by a light source and another of the images integrates multiple exposures during which the image is not illuminated by the light source. The image area can be illuminated by rapidly flashing the image area with the light source and synchronizing a shutter to permit one image sensor to capture an image when the image area is illuminated and another image sensor to capture the image area when the image area is not illuminated. These two images can be captured concurrently or nearly concurrently, thereby reducing or eliminating motion artifacts. Further, these apparatuses and techniques may do so with slow and relatively low-cost cameras and relatively low computational costs.