Person Counting via Diffractive Near-Infrared Triangulation
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Solution Overview
Problem
Existing methods for counting entering and exiting persons and objects in public transportation environments are inefficient due to high energy consumption, unreliable results from varying material reflections, and complexity in integration, especially in low-contrast scenes and ambient light conditions.
Innovation Solution
A method using continuous monochromatic near-infrared radiation (780 nm to 1000 nm) with a diffractive optical element to create a light pattern that allows for efficient beam energy use and reliable detection, enabling accurate counting through a 3D point cloud analysis, even in varying ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are used for counting persons and objects, then counting accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the detection task into two functional parts: a radiation source for illumination and a radiation detector for signal reception. This segmentation allows the system to achieve accurate counting through triangulation without requiring multiple complete sensor assemblies, thereby reducing overall device complexity while maintaining measurement precision.
Solution Approach 2:
The radiation detector serves multiple functions: it detects the emitted radiation, receives backscattered radiation from persons and objects, and provides data for both counting and classification. This multi-functionality eliminates the need for separate sensors for different detection tasks, reducing device complexity while maintaining accurate counting capability.
2Measurement precision
If short modulated light pulses are used for ToF detection, then 3D information is obtained, but energy consumption increases
Solution Approach 1:
Instead of using short modulated light pulses, the patent employs continuous radiation emission. This periodic action principle allows the system to obtain the necessary temporal information for triangulation and 3D detection without the high peak power demands of pulsed operation, significantly reducing energy consumption while maintaining measurement precision.
3Illumination intensity
If high intensity light pulses are used for illumination, then sufficient reflected brightness is achieved, but heat generation increases
Solution Approach 1:
The patent uses continuous radiation emission rather than intermittent high-intensity pulses. This continuous action provides sufficient illumination for detecting backscattered radiation from persons and objects without the thermal spikes associated with pulsed operation, maintaining reflected brightness while minimizing heat generation and simplifying thermal management.
4Device complexity
If light reflection intensity is used for detection, then detection is simplified, but reliability decreases due to varying material properties
Solution Approach 1:
The patent transitions from relying solely on light intensity (one dimension) to using triangulation based on spatial position and angle of arrival (multiple dimensions). By detecting the direction and position of backscattered radiation, the system achieves reliable counting that is independent of the reflective properties of different materials, while maintaining relatively simple detection electronics.
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 solution provides accurate, reliable, and cost-effective person and object counting in public transportation environments by minimizing energy consumption and improving detection reliability across different lighting conditions.
Implementation Method 1
deflecting the radiation with an element for deflecting the radiation, generating a light pattern in a detection region
Implementation Method 2
detecting the radiation backscattered by persons and/or objects situated in the detection region in a radiation detector
Data Source
AI summary
The invention relates to a method for distinguishing, detecting and counting persons and/or objects in vehicles for conveying persons and/or goods, with the method steps: emitting radiation from a radiation source, deflecting the radiation with an element for deflecting the radiation, generating a light pattern in a detection region with a beam density ρs of 5*102/4*πsr−1≤ρs≤106/4*πsr−1, and detecting the radiation backscattered by persons and/or objects situated in the detection region in a radiation detector, as well as a corresponding person and/or object counting device.