Ambient Light Sensing Using Weighted Sensor Fusion
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Solution Overview
Problem
Camera systems struggle to accurately differentiate between daytime and nighttime conditions, especially when artificial light sources like streetlights or car headlights are present, leading to incorrect illumination source activation.
Innovation Solution
The camera system employs multiple ambient light sensors with different fields of view or a moveable optical element to calculate a weighted average of light signals, determining the ambient light level and deciding whether to activate NIR LEDs for enhanced image production in low-light conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single light sensor is used to detect ambient light levels, then the device complexity is reduced, but the measurement precision deteriorates due to interference from artificial light sources
Solution Approach 1:
The patent divides the light sensing function into multiple sensors with different fields of view. The first light sensor detects light from a first direction while the second light sensor detects light from a second direction. By segmenting the sensing function across multiple sensors, the system can differentiate between ambient light and artificial light sources, thereby improving measurement precision without requiring a single overly complex sensor.
Solution Approach 2:
The patent introduces a spatial dimension to light detection by using sensors oriented at different angles. The first light sensor is configured to receive light from a first direction and the second light sensor from a second direction, creating angular separation. This dimensional approach allows the system to distinguish light sources based on their direction of origin, improving accuracy while maintaining relatively simple sensor components.
2Measurement precision
If multiple light sensors with different fields of view are used, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The movable optical element serves multiple functions: it can position itself to allow light from different directions to reach the light sensor, and it can also block light sources from specific directions. This single component performs what would otherwise require multiple fixed optical paths or multiple sensors with complex mounting arrangements, thereby improving measurement precision while limiting the increase in device complexity.
3Measurement precision
If artificial light sources are included in the sensor field of view, then the device complexity is reduced, but the measurement precision deteriorates due to light confusion
Solution Approach 1:
The patent employs a movable optical element that can dynamically adjust its position to control which light sources enter the sensor field of view. By moving the optical element, the system can exclude artificial light sources from the measurement path while maintaining sensitivity to ambient light, thereby improving measurement precision. The dynamic nature of this solution avoids the need for complex fixed optical path designs.
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 provides a more accurate representation of ambient light conditions, reducing confusion from artificial light sources and ensuring appropriate illumination, resulting in enhanced image quality in various lighting scenarios.
Implementation Method 1
A first light sensor may be provided and have a first field of view. A second light sensor may be provided and have a second field of view.
Implementation Method 2
In the first position light is received by the light sensor after passing through the moveable optical element
Implementation Method 3
a reflective optical element configurable to reflect light from an angle into the light sensor
Data Source
AI summary
A camera system includes a camera, an illumination source, a first light sensor having a first light sensor output, and a second light sensor having a second light sensor output. A processor has inputs coupled to the camera's output, the first light sensor output, and the second light sensor output, and the processor has an output coupled to the input of the illumination source. The processor receives a first light signal from the first light sensor output, receive a second light signal from the second light sensor output, determine a first weight for the first light signal and a second weight for the second light signal based on a difference between the first and second light signals, calculate a weighted average of the first and second light signals using the first and second weights, and determine whether to turn on the illumination source based on the weighted average.