Filterless Camera Laser Positioning Against Ambient Light Interference
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Solution Overview
Problem
Existing structured-light modules using infrared filters in cameras for laser positioning suffer from high costs and interference issues under varying ambient light conditions, leading to loss of environmental information and inaccurate obstacle detection.
Innovation Solution
A laser positioning method using a structured-light module with a camera without an infrared filter, employing inter-frame tracking and brightness centroid algorithms to detect and filter out ambient light interference, allowing for accurate detection of line laser light positions in both bright and dark frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an infrared filter is used in the camera module to filter ambient light, then the interference from non-infrared light is reduced, but a large amount of environmental information is lost and the cost increases
Solution Approach 1:
The patent segments the light detection process into two distinct phases: bright frames capture environmental information including visible light, while dark frames capture laser line information with reduced ambient light interference. This temporal segmentation allows the system to obtain both environmental context and precise laser positioning without using an infrared filter.
Solution Approach 2:
The system employs periodic switching between capturing bright frames and dark frames at different exposure times. This periodic action enables the camera to alternately prioritize environmental information capture and laser line detection, effectively separating the two functions in time rather than using spatial filtering.
2Measurement precision
If an infrared filter is used to separate infrared light from ambient light, then the accuracy of laser position detection is improved, but the cost increases and interference points increase under high ambient light
Solution Approach 1:
The patent implements dynamic adjustment of exposure times for bright and dark frames based on ambient light conditions. The system adaptively modifies the exposure parameters in real-time, allowing the camera to optimize its sensitivity for laser detection without requiring fixed optical filters or complex hardware modifications.
Solution Approach 2:
The system changes the exposure time parameter differently for bright frames and dark frames. By setting the dark frame exposure time shorter than the bright frame exposure time, the system creates a temporal parameter difference that naturally filters out ambient light while preserving laser line information, eliminating the need for infrared filters.
3Loss of information
If the camera is sensitive to both infrared and visible light bands, then the environmental information is retained, but the ambient light interference increases
Solution Approach 1:
The patent segments the image processing into two distinct types: bright frame processing that captures environmental information, and dark frame processing that extracts laser line positions. This segmentation allows the system to utilize information from both light bands appropriately for each processing stage without mutual interference.
Solution Approach 2:
The system maintains continuous capture of both bright and dark frames in sequence, ensuring uninterrupted acquisition of environmental information and laser positioning data. This continuous alternating capture ensures that both types of information are consistently obtained without gaps, maintaining system responsiveness.
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 method enables precise obstacle detection and navigation by retaining infrared and visible light details, reducing misjudgment of interference points, and enhancing obstacle avoidance accuracy under varying light conditions.
Implementation Method 1
receive the infrared light emitted from the linear laser transmitter and reflected back from the surface of the obstacle
Implementation Method 2
The camera module can capture environmental images, and can also receive the reflected light resulting from the line laser light emitted onto the object
Data Source
Figure 1
AI summary
A laser positioning method based on image information, and a robot. The laser positioning method is executed by a robot equipped with a structured-light module, the structured-light module including a line laser transmitter and a camera without any infrared filter such that imaging information of infrared light and imaging information of visible light are retained in an image acquired by the camera. The laser positioning method includes: controlling, by the robot, the camera to capture one or more frames of image of reflected light of line laser light emitted from the line laser transmitter that is reflected back from a surface of an object to be detected, and detecting whether the one or more frames of image captured by the camera are bright or dark; when the robot detects that a current frame of image captured by the camera is a frame of bright image, the robot executes an inter-frame tracking algorithm to search for positions of line laser light from the current frame of image; when the robot detects that the current frame of image captured by the camera is a frame of dark image, the robot executes a brightness centroid algorithm to extract the positions of line laser light from the current frame of image.