Principle of Laser Measurement in Foot 3D Scanners and Its Influence on Orthotic Effect
Basic Working Principle of Laser 3D Scanners
A laser 3D scanner is a surveying instrument that acquires three-dimensional coordinate data of an object’s surface based on the principle of laser ranging.
Its core hardware system consists of key components including a laser emitter, receiver, time counter, rotating filter mirror, control circuit board, microcomputer, and CCD camera.
This non-contact measurement technology calculates the spatial coordinates of a target object by emitting laser pulses and receiving reflected signals, providing fundamental data for subsequent 3D modeling.
Laser scanning technology primarily employs three measurement principles: pulse ranging, phase comparison, and triangulation. Pulse ranging calculates distance by measuring the time difference between the emission and return of a laser pulse. This method achieves kilometer-level ranging but with relatively low accuracy.
Phase comparison measures distance by analyzing the phase difference between the emitted and reflected light, achieving millimeter-level accuracy but with a shorter effective range.
Triangulation calculates distance based on the geometric relationship between the laser emitter, receiver, and the measured object, making it suitable for short-range, high-precision measurements.
Application of Foot 3D Scanners
Data Acquisition and Processing Workflow of Laser Scanning
The workflow of a 3D laser scanning system can be divided into three main stages: data acquisition, data processing, and 3D reconstruction.
In the data acquisition stage, the laser emits a pulsed laser beam, and the photodetector precisely records the time difference of the reflected signal. Simultaneously, a high-precision angular encoder records the scanning angle and orientation parameters, generating raw, dense point cloud data.
During this process, the system uses a regularly distributed point cloud acquisition method to ensure data density and uniformity, providing a reliable foundation for subsequent modeling.
For large objects or areas beyond the range of a single scan, modern scanners are typically equipped with automatic registration algorithms.
The system can automatically align and merge multiple local point cloud datasets acquired from segmented measurements, ensuring the completeness and consistency of the final model.
In the data processing stage, advanced filtering algorithms effectively remove noise points, improving data quality. Finally, surface reconstruction algorithms convert the processed point cloud into an editable solid model, producing standard 3D surveying outputs.
Precision Assurance of Laser Scanning Technology in Foot Measurement
In foot measurement applications, laser 3D scanners generate sub-millimeter precision 3D point cloud coordinate data by emitting eye-safe laser pulses, receiving reflected signals, and combining spatial orientation parameters recorded by high-precision angular encoders. This high-precision measurement capability directly determines the effectiveness of subsequent orthotic device fabrication.
The core advantage of laser scanners lies in their non-contact measurement characteristic, avoiding potential foot deformation or discomfort caused by traditional contact-based methods.
Meanwhile, the focusing property of the laser beam enables high-resolution detail capture even for complex curved surfaces of the foot.
By calculating the spatial coordinates (X, Y, Z) of surface points based on the time of laser reflection, combined with texture information acquired by a high-resolution camera, the system ultimately generates a dense point cloud containing both geometric and color data, providing an accurate basis for the personalized customization of orthotic insoles.
