Gated Camera Micromirror Array Temporal Gating
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Solution Overview
Problem
Standard image sensors are too slow and insensitive for fast and repeated exposure in temporally gated applications, often requiring image intensifiers that pose challenges due to low damage threshold, cost, and size, especially in mesoscopic applications with less stringent gating requirements.
Innovation Solution
A gated camera system utilizing a micromirror array switch and high-sensitivity sensors like EM-CCD or CMOS devices, which allows for fast and scalable temporal gating of images, replacing traditional image intensifiers with a micromirror array that redirects light to achieve sub-microsecond switching and high signal-to-noise acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If standard image sensors are used for temporal gating, then device complexity is reduced, but switching speed and sensitivity are insufficient
Solution Approach 1:
The system segments the optical path control function by using a micromirror array to independently control light routing for each pixel or pixel group, enabling fast temporal gating without requiring the entire sensor to switch at once. This segmentation allows individual micromirrors to operate at high speeds while the sensor remains stationary.
Solution Approach 2:
A micromirror array is introduced as an intermediary component between the scene and the image sensor. This intermediary performs the temporal gating function by rapidly redirecting light to or from the sensor, enabling fast switching speeds while allowing the use of standard, less complex image sensors.
2Reliability
If image intensifiers are used to achieve fast gating, then sensitivity and gating speed improve, but damage threshold, cost, and size deteriorate
Solution Approach 1:
The invention extracts the temporal gating function from the image intensifier system and implements it separately using a micromirror array. This separation allows the use of standard image sensors without the need for bulky and expensive image intensifiers, while still achieving fast gating capabilities. The micromirror array handles the fast switching, allowing the sensor to operate at its full dynamic range.
Solution Approach 2:
The micromirror array provides a cost-effective alternative to image intensifiers. By using relatively inexpensive micromirror technology combined with standard sensors, the system achieves similar performance to expensive image intensifier systems without the associated cost, size, and damage threshold limitations.
3Productivity
If micromirror array is used for temporal gating, then switching speed and scalability improve, but signal-to-noise ratio may deteriorate due to low duty cycle
Solution Approach 1:
The system employs periodic gating action through the micromirror array, which rapidly switches between admitting and blocking light in a repeating cycle. This periodic action enables high repetition rates for temporal gating while maintaining precise control over the duty cycle, allowing optimization between switching speed and signal accumulation.
Solution Approach 2:
The micromirror array enables continuous temporal gating operation at high repetition rates. By maintaining continuous periodic gating action rather than intermittent operation, the system can accumulate signal over multiple cycles while maintaining high productivity, thereby improving signal-to-noise ratio through temporal integration.
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
The camera system enables efficient temporal gating with low mass and rapid response, achieving high signal-to-noise acquisition and increasing dynamic range, while being scalable and cost-effective compared to traditional systems.
Implementation Method 1
The micromirror array redirects light away from, or toward the sensor in a controlled manner, allowing temporal gating of the formed image in time scales as low as several hundred nanoseconds.
Data Source
AI summary
A gated camera has an image-sensing device, a spatial-light modulator that directs part or all of an incident optical beam toward the image-sensing device or away from the image-sensing device under control of a controller; and a beam-directing element that directs the incident optical beam toward the spatial-light modulator. A gated image acquisition method includes controlling whether a temporal segment of an incident optical beam contributes to an image captured by an image sensor by directing the temporal segment either toward the image sensor or away from the image sensor. A method for spatially encoding a temporally-varying light signal comprising, for each of a plurality of temporal segments of the temporally-varying light signal selectively directing the temporal segment of the temporally-varying light signal to a respective region of an image sensor, or directing the temporal segment of the temporally-varying light signal away from the image sensor.