Spatial Temporal Modulation for Backscattering Elimination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In heavy fog conditions, conventional vehicle headlamps and fog lights struggle to provide adequate illumination and visibility due to scattering, leading to reduced brightness and contrast of road features and increased glare, which impairs driving safety.
Innovation Solution
An image capture apparatus with a light source, spatial modulator, and lock-in detector that alternates between localized and diffusive illumination patterns to suppress backscattered light from fog, enhancing the signal-to-noise ratio and improving image clarity through lock-in detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-beam headlamps are used in fog conditions, then illumination intensity is improved, but backscattered light increases causing glare and reducing visibility
Solution Approach 1:
The patent applies periodic temporal modulation to the light source, switching between localized illumination patterns and diffusive illumination patterns at specific frequencies. This periodic action creates a time-varying signal that can be distinguished from the static or slowly varying backscattered light, allowing the detection system to filter out glare while maintaining effective illumination.
Solution Approach 2:
The illumination is segmented into two distinct patterns: localized illumination that concentrates light on specific target areas, and diffusive illumination that spreads light broadly. By alternating between these segmented illumination modes, the system creates distinguishable signal characteristics that enable separation of target-reflected light from fog-backscattered light through temporal modulation.
2Object-affected harmful factors
If conventional fog lights are used, then visibility is improved compared to high-beam, but scattering still limits image clarity and contrast
Solution Approach 1:
The system employs dynamic spatial modulation through the spatial light modulator, which can rapidly change the illumination pattern configuration. This dynamic capability allows the system to adapt illumination distribution in real-time, creating time-varying signals that enhance the detectability of target features against the scattering background, thereby improving image clarity and contrast.
Solution Approach 2:
By implementing periodic switching between different spatial illumination patterns, the system creates a modulated signal that carries target information at specific frequencies. This periodic action enables the detection system to distinguish target-reflected light from the scattered light background through frequency-based filtering, significantly improving measurement precision in fog conditions.
3Object-affected harmful factors
If spatial and temporal modulation is applied with alternating patterns, then backscattered light is suppressed, but device complexity increases
Solution Approach 1:
The spatial light modulator serves multiple functions simultaneously: it performs spatial pattern generation, temporal modulation, and beam steering. This multi-functionality consolidates what would otherwise require separate components into a single device, reducing overall system complexity while achieving effective backscattered light suppression through coordinated spatial-temporal modulation.
Solution Approach 2:
The spatial light modulator acts as an intermediary between the light source and the target, shaping and modulating the illumination before it interacts with the scattering medium. This intermediary function allows precise control over the illumination characteristics without requiring complex modifications to the light source itself, simplifying the overall system architecture.
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 system effectively eliminates backscattered glare and enhances visibility by distinguishing the signal from the target from the backscattered light, resulting in improved image quality and reduced distortion, allowing for clearer imaging through fog and other scattering media.
Implementation Method 1
a modulator configured to modulate light irradiated from the light source to target object
Implementation Method 2
the reflected light from the target object being detected at a lock-in detector
Implementation Method 3
Brightness due to the backscattered light from the fog particles glares in front of the driver
Data Source
AI summary
An image capture apparatus includes a light source, a modulator configured to modulate light irradiated from the light source to a target object, an imaging device configured to generate image data by capturing one or more images of the target object, and processing circuitry. The processing circuitry is configured to drive the modulator by a first modulation signal, the first modulation signal being for irradiating a first pattern, drive the modulator by a second modulation signal, the second signal being for irradiating a second pattern, wherein the first pattern and the second pattern are irradiated alternately, modulate reflected light from the target object, the reflected light from the target object being detected at a lock-in detector, and generate an image composed of image data from the reflected light of the plurality of localized illuminations.