Monitoring Camera Reference Voltage Adjustment for Focal Length Variations
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Solution Overview
Problem
Existing day-and-night monitoring cameras face issues with overexposure or underexposure due to changes in light passing through the lens, as the light sensor cannot properly operate when the focal length is modulated, and existing technologies fail to effectively determine IR-cut filter switching or IR LED operations based on image brightness.
Innovation Solution
A monitoring camera system comprising a light sensor, a voltage comparing unit, and a reference voltage generating unit that adjusts reference voltages based on induced current comparisons to determine and perform IR emission, IR-cut filter switching, and black/white image mode switching operations, ensuring proper operation despite changes in focal length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the focal length of the lens is modulated to adapt to different monitoring scenarios, then the monitoring range and flexibility are improved, but the light sensor cannot properly operate causing overexposure or underexposure issues
Solution Approach 1:
The patent implements dynamic reference voltage adjustment based on the focal length state of the lens. When the lens focal length is changed, the system dynamically modifies the reference voltage to match the new light transmission conditions, ensuring the light sensor continues to operate reliably across different monitoring ranges and focal length configurations
Solution Approach 2:
The system changes the reference voltage parameter in response to focal length modulation. By adjusting this critical parameter, the system compensates for variations in light transmission caused by different focal lengths, maintaining proper light sensor operation and preventing exposure issues while preserving monitoring flexibility
2Speed
If the light sensor is used to determine IR-cut filter switching or IR LED operation, then the response speed is improved, but the system fails when light amount changes with focal length modulation
Solution Approach 1:
The system dynamically adjusts the reference voltage based on the actual focal length state, enabling the light sensor to maintain reliable operation across different focal length configurations. This dynamic adaptation ensures that mode switching determinations remain accurate and reliable regardless of changes in light transmission caused by focal length modulation
Solution Approach 2:
The system incorporates feedback regarding the focal length state to adjust the reference voltage accordingly. This feedback mechanism ensures that the light sensor's output is properly interpreted for mode switching decisions, maintaining reliability by compensating for the relationship between focal length changes and light transmission variations
3Measurement precision
If the industry technology uses image brightness to determine mode switching, then the accuracy is improved, but the system cannot further utilize image brightness when IR LEDs are already turned on
Solution Approach 1:
The patent segments the mode switching process into multiple stages with different reference voltages. By dividing the determination process into distinct phases (first mode switching with first reference voltage, second mode switching with second reference voltage), the system can accurately determine each mode transition based on image brightness without interference from already-activated IR LEDs
Solution Approach 2:
The system changes the reference voltage parameter according to the current operational state and focal length. This parameter adjustment enables multi-stage mode switching by providing different reference levels for different switching decisions, allowing the system to fully utilize image brightness information across multiple determination stages even when IR LEDs are activated
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 adjusts its mode switching operations to maintain appropriate image exposure by altering reference voltages in response to changing environment brightness, ensuring the monitoring camera operates correctly across varying light conditions.
Implementation Method 1
The light sensor is configured to sense an environment brightness of the monitoring camera and generate an induced current accordingly
Data Source
AI summary
A monitoring camera and an operation method thereof are provided. The monitoring camera includes a light sensor, a voltage comparing unit and a reference voltage generating unit. The light sensor senses an environment brightness of the monitoring camera and generates an induced current accordingly. The voltage comparing unit generates a sensing voltage according to the induced current and compares the sensing voltage and a reference voltage to obtain a first comparison result, so that the monitoring camera can determine whether to perform at least one of a plurality of mode switching operations according to the first comparison result. The reference voltage generating unit outputs the first reference voltage and determines whether to reduce the first reference voltage according to the first comparison result.