Infrared Illumination Modulation for Camera Day-Night Switching
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Solution Overview
Problem
Existing methods for determining when to switch between night and day modes in cameras with infrared illumination struggle with noise components and reduced light levels, making it difficult to accurately assess when additional illumination is no longer needed and/or to remove the infrared-cut filter from the optical path.
Innovation Solution
A method involving modulating the emission from infrared illumination sources between two intensities at a specific frequency, capturing images, and analyzing radiation level indicators to determine if the modulated frequency is detected, allowing the illumination to be turned off when not needed, and adjusting the infrared-cut filter accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If infrared illumination is continuously used to improve night vision quality, then image quality in low-light conditions is improved, but energy consumption increases
Solution Approach 1:
The system uses periodic modulation of the infrared illuminator at a specific frequency and detects this modulation in the captured images. By switching between on and off states periodically and analyzing the modulated signal presence, the system determines when infrared illumination is actually needed, enabling energy-saving shutdown when ambient light is sufficient.
2Illumination intensity
If infrared-cut filter is removed to allow infrared detection, then low-light image quality is improved, but infrared light interference during daytime occurs
Solution Approach 1:
The system continuously monitors captured images for the presence of modulated infrared signals and ambient light levels. Based on this feedback, it dynamically controls the infrared-cut filter position and illuminator state, switching between day mode (filter inserted) and night mode (filter removed) to optimize image quality while preventing infrared interference during daytime.
3Extent of automation
If ambient light level assessment methods are used to determine mode switching, then automatic day/night mode transition is achieved, but noise components and reduced light levels make accurate assessment difficult
Solution Approach 1:
The system performs preliminary modulation of the infrared illuminator at a known frequency before making mode switching decisions. By embedding this known modulation signal in advance and detecting its presence or absence in the captured images, the system creates a reliable reference that enables accurate automatic mode transition determination even in noisy or low-light conditions.
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 method provides a simple, robust, and energy-efficient way to control infrared illumination, ensuring accurate switching between night and day modes by minimizing noise interference and reducing energy consumption.
Implementation Method 1
infrared light emitting diodes
Implementation Method 2
infrared light and/or near infrared light
Implementation Method 3
image sensor without the infrared-cut filter will detect it
Data Source
AI summary
A method and a video capturing system for controlling at least one infrared (IR) illumination source, illuminating an area captured by a camera, the method comprising modulating emission from the IR illumination source between first and second emission intensities at a first frequency during a first predetermined time period. Upon capturing images using an image sensor of the camera during the first predetermined time period, determining a radiation level indicator for each of a plurality of images captured by the image sensor. Further, evaluating a sequence of determined radiation level indicators to determine whether a frequency resulting from the modulated emission at the first frequency is detected in the sequence of radiation level indicators. If the frequency resulting from the modulated emission at the first frequency is determined as not detected in the sequence of radiation level indicators, the IR illumination source is stopped.