Comparison of geometrical accuracy of active devices for 3D orthopaedic reconstructions

Abstract

The use of 3D digitizing tools is becoming the base for subject-specific products, such as the orthopaedic production process of orthoses and prostheses. This paper aims at comparing the metrological behaviour of low-cost devices (Kinect 1 and 2 by Microsoft, Structure Sensor by Occipital) and high-resolution active sensors (O&P Scan by Rodin4D, NextEngine Ultra HD, Konica Minolta Vivid 9i, GOM ATOS II 400 and Artec Leo) for the survey of human body parts. A calibrated flat plane and a test-field composed of eight calibrated spheres of different radii and placed at different heights were used to evaluate the standard quality parameters (flatness, probing errors in form and size and the standard deviation) for each device as recommended by the VDI/VDE 2634 guidelines. Subsequently, three different parts of a mannequin were surveyed as samples of human body parts. The results demonstrated the higher accuracy of fixed devices with respect to handheld ones, among which Artec Leo and Structure Sensor provided a satisfying level of accuracy for the orthopaedic application. Moreover, the handheld devices enabled performing a fast reconstruction of the mannequin parts in about 20 s, which is acceptable for a person that has to remain as still as possible. For this reason, the Structure Sensor was further tested with five motion approaches which identified that smooth motion provides the lowest deviation and higher reliability. The work demonstrated the appropriateness of handheld devices for the orthopaedic application requirements in terms of speed, accuracy and costs.

Comparison of multiple 3D scanners to capture foot, ankle, and lower leg morphology

“…Redaelli et al 17 compared 3 low-cost devices (SS I, Kinect 1, and Kinect 2) against a high-resolution laser scanner (GOM ATOS II 400) for the fabrication of orthotic devices by scanning the hand, thigh, and chest regions of a mannequin. Among these low-cost devices, SS I was found to have acceptable accuracy with mesh sizes of 0.6 mm, 1.2 mm, and 1.6 mm for the hand, thigh, and chest, respectively.…”

“…Among these low-cost devices, SS I was found to have acceptable accuracy with mesh sizes of 0.6 mm, 1.2 mm, and 1.6 mm for the hand, thigh, and chest, respectively. 17 Zahia et al 18 compared the SS I and Go!Scan 20 to scan the abdomen and identified SS I to be superior for speed, ease of use, and size obstruction. However, although these studies compared the performance measures of different 3D scanners, none have assessed 3D scanning of the foot and ankle regions for the fabrication of AFOs.…”

The Use of Smartphone Photogrammetry to Digitise Transtibial Sockets: Optimisation of Method and Quantitative Evaluation of Suitability

“…Structured light scanners are handheld and portable, and provide real-time scanning, whereas laser scanners can be static with a set measurement volume, such as the one in the study mentioned previously [26]. Davide et al investigated the difference between high-and low-cost scanning equipment; this highlighted that whilst high and low cost fixed scanners may have increased accuracy, the set up and scan time would limit their applications in prosthetics when compared to hand held devices for direct limb scanning [28]. Smartphone photogrammetry can be considered handheld as it uses a mobile device with no fixed measurement volume; currently, however, there are no real-time scanning options available on common smartphones suitable for prosthetic applications.…”

Test-Retest Reliability of Sole Morphology Measurements Using a Novel Single-Image-Based Pin-Array Impression Reconstruction Method

“…With the advance of 3D scanning technology, it is possible to use 3D scanners to scan the shape of the foot [20,[27][28][29][30][31]. Three major types of 3D scanning methods have been developed and used for body shape reconstruction, namely laser sensors [27,28,30], depth sensors [31,32], and photogrammetry [20,29,33].…”

“…With the advance of 3D scanning technology, it is possible to use 3D scanners to scan the shape of the foot [20,[27][28][29][30][31]. Three major types of 3D scanning methods have been developed and used for body shape reconstruction, namely laser sensors [27,28,30], depth sensors [31,32], and photogrammetry [20,29,33]. However, for the measurement of the foot, a major limitation of the existing 3D scanning methods is that it only works during non-weight-bearing conditions because the sole of the foot cannot be measured when it is in contact with the floor under weight-bearing conditions.…”