Gated Imaging Sensor Timing for Backscatter Reduction
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Solution Overview
Problem
Optical observation systems face challenges in low-light conditions and inclement weather, leading to reduced image quality and contrast due to backscatter from atmospheric particles, which limits target detection and identification ranges, especially at night.
Innovation Solution
A gated imaging system with active illumination that synchronizes the imaging sensor with the timing of light pulses to minimize backscatter by deactivating the sensor during the initial reflection from nearby particles and activating it only when reflections from the target arrive, allowing for progressive increase in received energy with range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an auxiliary light source is used to illuminate a target at night, then image quality is improved, but backscatter from atmospheric particles causes self-blinding and reduces contrast
Solution Approach 1:
The system performs preliminary range measurement to determine the distance to the target before illumination. This allows the sensor gate to be precisely timed to open only after the illumination pulse has reached the target and the backscatter from nearby particles has subsided, thereby preventing self-blinding while maintaining target illumination.
Solution Approach 2:
The sensor gate timing is dynamically adjusted based on the measured range to the target. The gate delay and duration are optimized in real-time to match the round-trip time of light to the target and back, allowing the system to adapt to varying target distances and environmental conditions while minimizing backscatter interference.
2Manufacturing precision
If a long focal lens is used to achieve high optical magnification, then target detail resolution is improved, but light collecting capability is reduced due to high f number
Solution Approach 1:
The system uses active illumination with high-intensity laser pulses to compensate for the reduced light collecting capability of long focal lenses. By controlling the illumination intensity and timing, the system ensures sufficient light reaches the sensor to achieve adequate image resolution despite the high f number of the lens.
Solution Approach 2:
The system employs pulsed illumination synchronized with the sensor gate timing. The periodic pulsing of the light source at optimized intervals allows accumulation of sufficient signal over multiple pulses while maintaining high temporal resolution, thereby achieving both good image quality and effective light utilization.
3Quantity of substance
If the sensor is activated continuously to capture reflections, then all reflected light is received, but backscatter from nearby particles blinds the sensor and reduces contrast
Solution Approach 1:
The system performs preliminary range measurement to determine the distance to the target before activating the sensor. This preliminary information is used to calculate the optimal gate delay time, ensuring the sensor is activated only after backscatter from nearby particles has subsided, thereby receiving target reflections without sensor blinding.
Solution Approach 2:
The sensor operates in periodic gated mode rather than continuously, with each gate opening synchronized to the expected arrival time of target reflections. This periodic activation reduces exposure to harmful backscatter while capturing sufficient reflected light from the target, thereby improving contrast and preventing sensor blinding.
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 enhances image quality and extends detection ranges by reducing self-blinding effects and ambient light interference, enabling effective target identification in various environmental conditions without requiring preliminary range measurements.
Implementation Method 1
A transmission source provides at least one energy pulse. A sensor receives pulse reflections of the at least one energy pulse reflected from objects
Implementation Method 2
the sensor starts to receive the pulse reflections after a delay timing substantially given by the time it takes the at least one energy pulse to reach the minimal range and complete reflecting back
Implementation Method 3
The sensor is enabled to gate detection of the pulse reflections, with a gate timing which is controlled such that the sensor starts to receive the pulse reflections after a delay timing substantially given by the time it takes the at least one energy pulse to reach the minimal range
Data Source
AI summary
An imaging system, including a transmission source providing pulse(s), and a gated sensor for receiving pulse reflections from objects located beyond a minimal range. The pulse and the gate timing are controlled for creating a sensitivity as a function of range, such that the amount of the energy received progressively increases with the range. Also an imaging method, including emitting pulse(s) to a target area, receiving reflections of pulses reflected from objects located beyond a minimal range, the receiving includes gating detection of the reflections, and progressively increasing the received energy of the reflections, by controlling the pulses and the timing of the gating.