Active-Gated Imaging Mitigating Saturation from High-Intensity Sources
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Active-gated imaging systems face challenges with high-intensity sources such as retroreflective signs and vehicle headlights, leading to image saturation and blooming effects, which obscure relevant features and increase the risk of accidents due to delayed hazard detection.
Innovation Solution
An active-gated imaging system with a light source, gated camera, and image processor that emits light pulses synchronized with the camera's exposure, acquiring a main image frame and a low-illumination secondary frame using a reduced illumination scheme to mitigate oversaturation, allowing for image merging and adaptive control of gating parameters to reduce ambient light accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If active-gated imaging systems use standard illumination and accumulation schemes, then image brightness is sufficient for visibility, but high-intensity sources cause saturation and blooming effects that obscure relevant features
Solution Approach 1:
The patent segments the image acquisition process into multiple frames with different illumination levels. A first image frame is acquired using reduced illumination to capture high-intensity sources without saturation, while a second image frame is acquired using standard illumination for overall scene brightness. These segmented frames are then combined to produce a final image that maintains both source detail and scene visibility.
Solution Approach 2:
The patent applies different illumination qualities to different regions of the image. High-intensity source regions are imaged with reduced illumination to prevent saturation, while other regions use standard illumination for adequate brightness. This local differentiation allows each region to be captured at optimal exposure levels, resolving the contradiction between overall brightness and localized saturation.
2Measurement precision
If the camera accumulates more light pulses to improve image quality, then signal-to-noise ratio increases, but ambient light accumulation increases causing overexposure in bright conditions
Solution Approach 1:
The patent dynamically adjusts the illumination level based on scene conditions. The controller determines whether to use reduced illumination or standard illumination for acquiring the first image frame, and similarly adjusts the second frame's illumination. This dynamic adaptation allows the system to optimize signal-to-noise ratio while preventing overexposure by matching illumination levels to actual scene brightness requirements.
Solution Approach 2:
The patent changes the illumination parameter (light intensity) between different image frames and based on scene conditions. By varying the illumination level rather than using a fixed high level, the system can accumulate sufficient signal for good noise performance while avoiding the overexposure that would result from consistently high illumination accumulation.
3Illumination intensity
If gated imaging is used to reduce ambient light accumulation, then overexposure is prevented, but the number of gating cycles must be reduced which decreases image quality
Solution Approach 1:
The patent merges multiple image frames acquired with different gating cycle counts into a single composite image. The first frame uses a reduced number of gating cycles to prevent overexposure, while the second frame uses a standard number of gating cycles for adequate brightness. By combining these frames, the system achieves both overexposure protection and maintained image quality that would be difficult to obtain from a single frame.
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 generates high dynamic range images, effectively reducing saturation and blooming effects, enabling clearer identification of high-intensity sources and improving hazard detection, thereby enhancing safety in low-light conditions.
Implementation Method 1
The image sensor is configured to receive reflected pulses from a selected depth of field (DOF) in the environment
Implementation Method 2
the exposure mechanism of the image sensor includes a pixelated transfer gate from a photodiode to a floating diffusion node for each pixel in the sensor array
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Active-gated imaging system and method for imaging environment with at least one high-intensity source. A light source emits light pulses toward the environment, and an image sensor with a pixelated sensor array receives reflected pulses from a selected depth of field and generates a main image. The image sensor exposure mechanism includes a pixelated transfer gate synchronized with the emitted pulses. An image processor identifies oversaturated image portions of the main image resulting from a respective high-intensity source, and interprets the oversaturated image portions using supplementary image information acquired by image sensor. The supplementary information may be obtained from: a low-illumination secondary image having substantially fewer gating cycles than the main image; by accumulating reflected pulses from the high-intensity source after the reflected pulses undergo internal reflections between optical elements of the camera; or a low-illumination secondary image acquired by residual photon accumulation during a non-exposure state of image sensor.