IR LED Zone Illumination for Night Vision Exposure Control
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Solution Overview
Problem
Conventional IR LED illumination during night mode operations can lead to suboptimal image quality due to strong reflections from nearby objects, causing exposure control issues and skewing the average lighting response, which renders images unusable.
Innovation Solution
The method involves arranging IR LEDs into overlapping zones with adjustable power distribution, shifting the center of power away from the image center through tilting or optical lenses, and dynamically recalculating auto-exposure control parameters for each zone to optimize image brightness and mitigate hot or dark spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If strong infrared illumination is used to improve signal-to-noise ratio, then image brightness and detectability improve, but exposure control is thrown off and image quality deteriorates due to overexposure from strong reflections
Solution Approach 1:
The patent divides the illumination system into multiple zones with independent IR LED groups. Each zone can be controlled separately, allowing the system to segment the scene into regions that need different illumination levels. This prevents strong reflections from a single direction from overwhelming the entire image sensor, while still providing sufficient illumination across the whole field of view.
Solution Approach 2:
The patent implements different illumination characteristics for different spatial regions by controlling each IR LED zone independently. Areas with strong reflections receive reduced illumination intensity, while darker areas receive enhanced illumination. This local quality adjustment optimizes exposure control by matching illumination intensity to the specific needs of each region, preventing both overexposure and underexposure.
2Illumination intensity
If uniform infrared illumination is applied across the entire scene, then overall image brightness improves, but non-uniform reflections create hot or dark spots that degrade image quality
Solution Approach 1:
The patent employs dynamic control of IR LED zones based on real-time scene analysis. The system continuously monitors the image for hot or dark spots and adjusts the illumination intensity of each zone dynamically. This dynamic adaptation allows the system to maintain uniform illumination across the scene despite varying surface reflectivities and geometric configurations, eliminating the hot and dark spots that would result from static uniform illumination.
Solution Approach 2:
The patent implements a feedback mechanism where the image sensor detects the actual illumination效果 and feeds this information back to the control system. The controller analyzes the detected hot or dark spots and adjusts the IR LED zone intensities accordingly. This closed-loop feedback ensures that the illumination remains uniform across the scene by continuously compensating for variations in surface reflectivity and geometry.
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 approach improves power efficiency and uniformity, reducing the impact of reflections and ensuring better image quality by adjusting IR LED power based on exposure calculations for each zone, thereby optimizing the overall image response.
Implementation Method 1
IR LEDs can be used to illuminate the objects during night mode operations or night vision
Implementation Method 2
The more infrared power pumped into the scene, the more reflected light from the scene can be sensed by the image sensor
Implementation Method 3
the more reflected light from the scene can be sensed by the image sensor in the cameras
Data Source
AI summary
A method is provided for low light exposure control during night vision. The method may include actively illuminating a region by using a plurality of IR LEDs. The IR LEDs are arranged so that an IR LED of the plurality of IR LEDs covers one of a plurality of zones, which combine to cover the region. The method may also include capturing an image frame by an imaging system including an image sensor. The image frame may be made up of pixels and captured using the light originating from the plurality of IR LEDs and reflected from the region onto the image sensor. The method may also include calculating auto-exposure control (AEC) parameters for the image frame to establish an average setting, recalculating AEC parameters for a first zone the plurality of zones and adjusting the power of a first IR LED of the plurality of IR LEDs.