Night-Vision Imaging Apparatus Using Pseudo-Random Modulation
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Solution Overview
Problem
Conventional night-vision imaging apparatuses for vehicles struggle to effectively reduce the influence of oncoming vehicle headlights, as they rely on optical filters that require matching spectral characteristics, making it difficult to differentiate and attenuate near-infrared light emissions.
Innovation Solution
A night-vision imaging apparatus that emits infrared light modulated in a temporally pseudo-random manner, using a spread spectrum system, and employs multiple LEDs with different wavelengths and polarizations to uniquely identify and extract the infrared light emitted by the vehicle, thereby reducing interference from oncoming headlights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an optical bandpass filter with narrow transmission band is used to attenuate visible light from oncoming vehicles, then the transmission of laser beam is maintained, but the filter cannot attenuate near-infrared light from oncoming vehicles with identical spectral characteristics
Solution Approach 1:
The patent applies temporal modulation to the infrared light emission, creating a dynamic signaling system where the transmitted light varies in intensity over time according to a pseudo-random code. This dynamic approach allows the receiver to distinguish its own transmitted light from static or differently-modulated light sources of oncoming vehicles, solving the problem of spectral matching limitations without requiring adaptable filters.
Solution Approach 2:
The patent changes the temporal parameter of the infrared light by modulating it with a pseudo-random code sequence. Instead of relying on spectral parameter differentiation which fails when oncoming vehicles use identical lasers, the system uses temporal modulation patterns as the distinguishing feature, allowing reliable identification and extraction of own-vehicle light regardless of spectral characteristics.
2Object-affected harmful factors
If pulse modulation with electronic lock is used to attenuate oncoming vehicle light, then synchronization with laser beam is achieved, but the system becomes complex and requires precise timing coordination
Solution Approach 1:
The patent uses periodic modulation of the infrared light with a pseudo-random code sequence that repeats at known intervals. This periodic structure allows the receiver to use correlation detection to identify and extract the modulated signal from background light, achieving interference rejection without requiring complex electronic locking mechanisms or precise timing synchronization with external sources.
Solution Approach 2:
The system employs feedback through correlation detection where the received signal is compared with the known transmitted pseudo-random code. This feedback mechanism automatically identifies and extracts the desired signal while rejecting unmodulated or differently-modulated light from oncoming vehicles, simplifying the system compared to electronic lock approaches.
3Reliability
If far-infrared camera is used to capture far-infrared light from human beings and animals, then night vision capability is achieved, but the equipment becomes considerably expensive
Solution Approach 1:
Instead of using expensive far-infrared cameras to detect thermal radiation, the patent uses a visible/near-infrared camera to detect reflected modulated infrared light. The system creates an optical copy of the scene using inexpensive infrared illumination and standard camera sensors, achieving night vision functionality without requiring costly far-infrared detection equipment.
Solution Approach 2:
The patent replaces the thermal radiation detection mechanism (far-infrared camera) with an active illumination and reflection detection system using modulated infrared LEDs and standard cameras. This substitution uses simpler, more manufacturable components while achieving the same night vision objective.
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 solution allows for effective reduction of oncoming vehicle light interference, enabling continuous high-quality image capture without loss, and improves safety by enhancing visibility in low-light conditions.
Implementation Method 1
a light emission unit that emits infrared light
Implementation Method 2
a solid-state imaging device that converts the infrared light into a first signal
Data Source
AI summary
The invention provides a night-vision imaging apparatus including: a light emission unit that emits infrared light; a solid-state imaging device that converts the infrared light into a first signal; a light-emission control unit that allows the light emission unit to emit the infrared light which is modulated according to a temporally pseudo-random first modulation; and an extraction unit that extracts, according to the first modulation, a signal corresponding to the infrared light emitted by the light emission unit from the first signal.