Adaptive Flash Brightness Control for Night Monitoring Cameras
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Solution Overview
Problem
Monitoring cameras often struggle to capture high-quality images at night due to fixed-brightness flashlights, leading to overexposure at close distances and insufficient lighting at farther distances, especially in empty scenes.
Innovation Solution
A monitoring camera with an adaptive flash brightness control function that detects the distance of a moving object and adjusts the flashlight brightness accordingly, using a pyroelectric infrared sensor to determine the object's distance and a processing device to control the flashlight's brightness through a PWM driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If fixed-brightness flashlight is used for night monitoring, then the monitoring camera can capture images at night, but the object is overexposed at close distance
Solution Approach 1:
The patent applies dynamics by making the flashlight brightness adjustable rather than fixed. The brightness is dynamically changed based on the distance to the detected object, allowing the system to adapt to different monitoring scenarios and avoid overexposure at close ranges while maintaining sufficient illumination at distances.
Solution Approach 2:
The patent changes the parameter of flashlight brightness according to the distance parameter. By detecting the object distance and adjusting the brightness parameter accordingly, the system resolves the contradiction between providing sufficient light and avoiding overexposure at close distances.
2Device complexity
If fixed-brightness flashlight is used for night monitoring, then the monitoring camera can operate simply, but insufficient light is provided at farther distances
Solution Approach 1:
The system transitions from a static fixed-brightness flashlight to a dynamic adjustable-brightness system. This allows the flashlight to provide sufficient illumination at far distances when needed, while maintaining operational simplicity through automated control based on distance detection.
3Adaptability or versatility
If AE (Automatic Exposure Control) is used to adjust exposure brightness, then the camera can adapt to lighting conditions, but close-range overexposure problem persists at night
Solution Approach 1:
The patent introduces an intermediary mechanism - the adjustable brightness flashlight controlled by distance detection. This intermediary system works between the camera's AE control and the actual lighting condition, providing a dedicated solution for close-range overexposure that complements the AE function.
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 adaptive flash brightness control ensures appropriate lighting for moving objects at various distances, preventing overexposure and ensuring sufficient illumination, thereby improving image quality in night-time monitoring scenarios.
Implementation Method 1
a pyroelectric infrared sensor to detect the moving object entering the camera range of the monitoring camera
Data Source
AI summary
A monitoring method of a monitoring camera and a monitoring camera with an adaptive flash brightness control function is provided. The monitoring method includes: detecting whether a moving object enters a camera range of the monitoring camera; if yes, determining a distance between the moving object and the monitoring camera; and adjusting the brightness of a flash light on the monitoring camera according to the distance between the moving object and the monitoring camera. By the monitoring method, the brightness of the flash light is adjusted according to the distance between the moving object and the monitoring camera, so that the monitoring camera provides appropriate brightness for the moving object at different distances within the camera range, thereby avoiding overexposure or underexposure to improve the quality of images.