Adaptive IR Illumination for Camera Exposure Correction
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Solution Overview
Problem
Security cameras in night mode often face issues with overexposure and underexposure due to indiscriminate infrared illumination, leading to poor image quality, especially when mounted near surfaces that reflect high levels of infrared light, causing important details to be hidden.
Innovation Solution
The system adapts IR illumination by adjusting its power and spatial distribution based on image processing analysis to correct overexposure and underexposure, using multiple IR illuminator elements that can be individually controlled, and combining these adjustments with camera settings like sensor gain and exposure time to maintain optimal image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If IR illumination is provided at high power to illuminate the scene in night mode, then the illumination level in dark areas is improved, but overexposure occurs in areas close to the camera causing loss of image detail
Solution Approach 1:
The patent divides the IR illuminator into multiple independently controllable elements (e.g., multiple IR LEDs arranged in an array). Each element can be controlled individually or in groups to provide different illumination levels to different regions of the scene. This segmentation allows the system to illuminate distant areas while avoiding overexposure of nearby areas, resolving the contradiction between providing sufficient illumination and preventing overexposure.
Solution Approach 2:
The patent implements local quality control by assigning different illumination characteristics to different parts of the illuminator. Specifically, illuminator elements directed toward nearby surfaces (which would cause overexposure) operate at lower power or are turned off, while elements directed toward distant areas operate at higher power. This creates a non-uniform illumination pattern that adapts to the spatial distribution of objects in the scene, ensuring adequate illumination without overexposure in specific regions.
2Device complexity
If IR illumination is provided uniformly across the entire field of view, then the implementation complexity is reduced, but image quality deteriorates due to overexposure in some areas and underexposure in others
Solution Approach 1:
The patent segments the IR illuminator into multiple independently controllable elements, allowing differential control across the field of view. This segmentation enables the system to adjust illumination levels in different regions to achieve uniform image quality across the entire scene, overcoming the limitations of uniform illumination while managing complexity through modular control architecture.
Solution Approach 2:
The patent implements dynamic control of the IR illuminator elements based on real-time scene analysis. The system adjusts the illumination power of individual elements or groups of elements in response to detected scene characteristics (such as presence of nearby reflective surfaces), enabling adaptive illumination that maintains optimal image quality across varying conditions without requiring overly complex predetermined control schemes.
3Adaptability or versatility
If the camera is mounted near surfaces that reflect infrared light, then installation flexibility is improved, but image quality deteriorates due to saturation artifacts from reflected IR light
Solution Approach 1:
The patent extracts or removes the harmful reflected IR light from the image by selectively controlling the illuminator elements that would cause saturation. When nearby reflective surfaces are detected, the corresponding illuminator elements are turned off or operated at reduced power, effectively removing the source of saturation artifacts while maintaining illumination from other elements that do not cause reflection issues.
Solution Approach 2:
The patent applies local quality control to address installation near reflective surfaces. By analyzing the scene to identify nearby surfaces and their reflective properties, the system selectively adjusts the illumination characteristics of specific illuminator elements directed toward those surfaces, reducing or eliminating reflected IR light while maintaining adequate illumination from other directions. This allows flexible installation positions without compromising image quality.
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 image quality by reducing saturation artifacts from nearby structures, ensuring that areas of interest are properly illuminated, preserving details and enhancing facial feature detection in surveillance images and videos.
Implementation Method 1
IR illuminator illuminated a scene using a first IR light
Implementation Method 2
capturing by the camera's image sensor a first image of the scene
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A system and method that provides adaptive 1 R illumination for a camera, in some implementations, IR illumination adapts to the objects in a scene being monitored and IR illumination adaptation may be implemented in conjunction with automatic exposure and other exposure adjustment methods, Some implementations include: illuminating a scene using a first IR. illumination power; capturing a first image of the scene with a camera; and determining whether a first region of the first image is underexposed or overexposed. When the first region is underexposed, the scene is illuminated at a second power level greater than the first illumination power and a second image is captured. When the first region is overexposed, the scene is illuminated at a third power level that is less than die first illumination power and a third image is captured. The operations may be repeated until scene illumination is satisfactory.