Vehicle Vision System High Dynamic Range Image Sensor
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Solution Overview
Problem
Vehicular night vision systems face challenges with washout and blooming due to limited dynamic range in image sensors, which hinder the detection of faint objects near bright sources like oncoming vehicle headlamps, and existing high dynamic range sensors are costly and complex.
Innovation Solution
A vehicular vision system utilizing a high dynamic range image sensor with antireflective coatings, narrow band NIR light sources, and image processing techniques to produce synthetic high dynamic range images by combining images with varying exposure times or attenuation filters, reducing optical reflections and enhancing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensitivity of the imager is set sufficiently high for adequate imaging of the scene when illuminated by a NIR light source, then the ability to detect faint objects is improved, but oncoming headlamps will substantially saturate the image sensor and limit the ability to see faint objects close in proximity to the oncoming vehicle
Solution Approach 1:
The patent applies dynamic adjustment of exposure time for different regions of the image sensor. The system varies exposure parameters in real-time based on local scene brightness, allowing high sensitivity for faint objects in dark regions while preventing saturation in bright regions near oncoming headlamps. This dynamic adaptation resolves the contradiction between detection sensitivity and saturation resistance.
Solution Approach 2:
The patent implements region-specific imaging parameters where different portions of the image sensor use different exposure times and gain settings. Dark regions use longer exposure for enhanced sensitivity, while bright regions use shorter exposure to avoid saturation. This local quality adjustment allows simultaneous optimization of both detection sensitivity and saturation prevention in different spatial zones.
2Reliability
If high dynamic range image sensors are used to solve the limited pixel dynamic range problem, then the ability to sense both bright headlamps and faint objects is improved, but the pixel construction becomes more complex and expensive
Solution Approach 1:
The patent uses periodic capture of multiple images with varying exposure times and combines them through image processing to achieve high dynamic range. Instead of modifying the pixel structure, the system takes sequential images at different exposures and merges them, achieving HDR functionality through temporal multiplexing rather than spatial pixel complexity.
Solution Approach 2:
The patent creates multiple copies of the same scene at different exposure levels and combines them to form a final high dynamic range image. Rather than building complex pixels, the system captures multiple simpler images and processes them together, using the copying approach to achieve enhanced dynamic range without increasing pixel structure complexity.
3Measurement precision
If conventional image sensors are used with high sensitivity settings, then faint objects can be detected, but electronic blooming occurs where electrons generated in one pixel spill over into neighboring pixels, resulting in bright objects being imaged as much larger than they actually are
Solution Approach 1:
The patent dynamically adjusts exposure time based on local brightness conditions to prevent electron overflow. By using shorter exposure times in bright regions where blooming occurs and longer exposure times in dark regions, the system maintains high sensitivity while preventing electronic blooming through temporal control rather than spatial electron trapping structures.
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 reduces blooming and improves sensitivity, allowing for better detection of faint objects near bright sources without saturating from oncoming headlamps, while being more economical and efficient than traditional high dynamic range sensors.
Implementation Method 1
A vehicular vision system utilizing a high dynamic range image sensor with antireflective coatings
Implementation Method 2
narrow band NIR light sources
Implementation Method 3
image sensor to either control a vehicle function or provide an image to a driver
Data Source
AI summary
A vehicular vision system is disclosed comprising a high dynamic range. The systems and methods are advantages for rear vision, collision avoidance, obstacle detection, adaptive cruise control, rain sensing, exterior light control, and lane departure warning, as well as other applications where a given scene may comprise objects having widely varying brightness values.