Rolling-Shutter CMOS Laser Impact Visualization for PRI Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing guided munitions with semi-active laser seekers face challenges in visualizing laser pulse impacts and estimating the pulse repetition interval (PRI) due to the complexity, size, and cost associated with adding avalanche photodiodes to Indium gallium arsenide CMOS sensors.
Innovation Solution
A method and device using a silicone-based CMOS sensor with a rolling shutter readout circuit and image processing circuit to detect transitions between exposed and unexposed rows, enabling estimation of laser pulse impacts and PRI without additional detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an avalanche photodiode-based laser spot tracker is added to the CMOS sensor to detect PRI, then the measurement precision of pulse repetition interval is improved, but the device complexity, size, consumption and cost increase
Solution Approach 1:
The patent makes the existing CMOS sensor perform dual functions: it continues to visualize laser spots while simultaneously measuring the pulse repetition interval through its rolling shutter readout circuit. The sensor serves itself by using its inherent row-by-row exposure mechanism to detect transitions caused by laser pulses, eliminating the need for separate PRI detection hardware.
Solution Approach 2:
The patent enables the CMOS sensor to perform multiple functions: it visualizes laser impact spots on targets and simultaneously measures the pulse repetition interval. By exploiting the rolling shutter readout circuit's sequential row exposure特性, the same sensor hardware achieves both spot detection and temporal interval measurement without requiring additional specialized detectors.
2Measurement precision
If an avalanche photodiode-based laser spot tracker is added to the CMOS sensor to detect PRI, then the measurement precision of pulse repetition interval is improved, but the size of the visualisation device increases
Solution Approach 1:
The patent enables the CMOS sensor to perform multiple functions: it visualizes laser impact spots on targets and simultaneously measures the pulse repetition interval. By exploiting the rolling shutter readout circuit's sequential row exposure特性, the same sensor hardware achieves both spot detection and temporal interval measurement without requiring additional specialized detectors.
3Measurement precision
If an avalanche photodiode-based laser spot tracker is added to the CMOS sensor to detect PRI, then the measurement precision of pulse repetition interval is improved, but the cost of the visualisation device increases
Solution Approach 1:
The patent makes the existing CMOS sensor perform dual functions: it continues to visualize laser spots while simultaneously measuring the pulse repetition interval through its rolling shutter readout circuit. The sensor serves itself by using its inherent row-by-row exposure mechanism to detect transitions caused by laser pulses, eliminating the need for separate PRI detection hardware.
4Reliability
If the exposure time is increased to capture laser pulse impacts, then the visualization reliability is improved, but the reading time requirement increases which may cause data loss
Solution Approach 1:
The patent optimizes the exposure time parameter within specific bounds (not less than reading time of one row but not more than the product of reading time and number of rows). This parameter adjustment ensures that the sensor captures complete laser pulse information across multiple rows while the rolling shutter mechanism prevents data loss by continuously exposing different rows during the pulse duration.
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 simple, reliable, and cost-effective visualization of laser pulse impacts and estimation of PRI, reducing complexity and cost by leveraging the inherent properties of CMOS sensors with rolling shutter readout circuits.
Implementation Method 1
a rolling shutter-type readout circuit
Implementation Method 2
an optronic sensor of the silicone-based CMOS type
Data Source
AI summary
A method for visualising impacts of laser pulses emitted by a laser designator, according to a predetermined repetition interval (PRI), onto a target present in a scene, by means of a device including: an optronic sensor of the silicone-based CMOS type having a predetermined number of rows associated with a rolling shutter-type readout circuit. Each row of the sensor is exposed for an exposure time and read during a reading time so that the exposure time is no less than the reading time but no more than the product of the reading time and the number of rows. A transition between the rows exposed to a signal and the rows not exposed to said signal is detected in at least two images in order to infer the PRI.