Automatic Multiview Alignment of RGB-D Range Maps of Upper Limb Anatomy

Digital representations of anatomical parts are crucial for various biomedical applications. This paper presents an automatic alignment procedure for creating accurate 3D models of upper limb anatomy using a low-cost handheld 3D scanner. The goal is to overcome the challenges associated with forearm...

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Main Authors: Luca Di Angelo, Paolo Di Stefano, Emanuele Guardiani, Paolo Neri, Alessandro Paoli, Armando Viviano Razionale
Format: Article
Language:English
Published: MDPI AG 2023-09-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/23/18/7841
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author Luca Di Angelo
Paolo Di Stefano
Emanuele Guardiani
Paolo Neri
Alessandro Paoli
Armando Viviano Razionale
author_facet Luca Di Angelo
Paolo Di Stefano
Emanuele Guardiani
Paolo Neri
Alessandro Paoli
Armando Viviano Razionale
author_sort Luca Di Angelo
collection DOAJ
description Digital representations of anatomical parts are crucial for various biomedical applications. This paper presents an automatic alignment procedure for creating accurate 3D models of upper limb anatomy using a low-cost handheld 3D scanner. The goal is to overcome the challenges associated with forearm 3D scanning, such as needing multiple views, stability requirements, and optical undercuts. While bulky and expensive multi-camera systems have been used in previous research, this study explores the feasibility of using multiple consumer RGB-D sensors for scanning human anatomies. The proposed scanner comprises three Intel<sup>®</sup> RealSenseTM D415 depth cameras assembled on a lightweight circular jig, enabling simultaneous acquisition from three viewpoints. To achieve automatic alignment, the paper introduces a procedure that extracts common key points between acquisitions deriving from different scanner poses. Relevant hand key points are detected using a neural network, which works on the RGB images captured by the depth cameras. A set of forearm key points is meanwhile identified by processing the acquired data through a specifically developed algorithm that seeks the forearm’s skeleton line. The alignment process involves automatic, rough 3D alignment and fine registration using an iterative-closest-point (ICP) algorithm expressly developed for this application. The proposed method was tested on forearm scans and compared the results obtained by a manual coarse alignment followed by an ICP algorithm for fine registration using commercial software. Deviations below 5 mm, with a mean value of 1.5 mm, were found. The obtained results are critically discussed and compared with the available implementations of published methods. The results demonstrate significant improvements to the state of the art and the potential of the proposed approach to accelerate the acquisition process and automatically register point clouds from different scanner poses without the intervention of skilled operators. This study contributes to developing effective upper limb rehabilitation frameworks and personalized biomedical applications by addressing these critical challenges.
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spelling doaj.art-308a11a592e8468abc70094e8e01487b2023-11-19T12:54:57ZengMDPI AGSensors1424-82202023-09-012318784110.3390/s23187841Automatic Multiview Alignment of RGB-D Range Maps of Upper Limb AnatomyLuca Di Angelo0Paolo Di Stefano1Emanuele Guardiani2Paolo Neri3Alessandro Paoli4Armando Viviano Razionale5Department of Industrial and Information Engineering and Economics, University of L’Aquila, 67100 L’Aquila, ItalyDepartment of Industrial and Information Engineering and Economics, University of L’Aquila, 67100 L’Aquila, ItalyDepartment of Industrial and Information Engineering and Economics, University of L’Aquila, 67100 L’Aquila, ItalyDepartment of Civil and Industrial Engineering, University of Pisa, 56122 Pisa, ItalyDepartment of Civil and Industrial Engineering, University of Pisa, 56122 Pisa, ItalyDepartment of Civil and Industrial Engineering, University of Pisa, 56122 Pisa, ItalyDigital representations of anatomical parts are crucial for various biomedical applications. This paper presents an automatic alignment procedure for creating accurate 3D models of upper limb anatomy using a low-cost handheld 3D scanner. The goal is to overcome the challenges associated with forearm 3D scanning, such as needing multiple views, stability requirements, and optical undercuts. While bulky and expensive multi-camera systems have been used in previous research, this study explores the feasibility of using multiple consumer RGB-D sensors for scanning human anatomies. The proposed scanner comprises three Intel<sup>®</sup> RealSenseTM D415 depth cameras assembled on a lightweight circular jig, enabling simultaneous acquisition from three viewpoints. To achieve automatic alignment, the paper introduces a procedure that extracts common key points between acquisitions deriving from different scanner poses. Relevant hand key points are detected using a neural network, which works on the RGB images captured by the depth cameras. A set of forearm key points is meanwhile identified by processing the acquired data through a specifically developed algorithm that seeks the forearm’s skeleton line. The alignment process involves automatic, rough 3D alignment and fine registration using an iterative-closest-point (ICP) algorithm expressly developed for this application. The proposed method was tested on forearm scans and compared the results obtained by a manual coarse alignment followed by an ICP algorithm for fine registration using commercial software. Deviations below 5 mm, with a mean value of 1.5 mm, were found. The obtained results are critically discussed and compared with the available implementations of published methods. The results demonstrate significant improvements to the state of the art and the potential of the proposed approach to accelerate the acquisition process and automatically register point clouds from different scanner poses without the intervention of skilled operators. This study contributes to developing effective upper limb rehabilitation frameworks and personalized biomedical applications by addressing these critical challenges.https://www.mdpi.com/1424-8220/23/18/7841depth cameras3D optical scanningupper limb anatomyautomatic point cloud alignmentneural network
spellingShingle Luca Di Angelo
Paolo Di Stefano
Emanuele Guardiani
Paolo Neri
Alessandro Paoli
Armando Viviano Razionale
Automatic Multiview Alignment of RGB-D Range Maps of Upper Limb Anatomy
Sensors
depth cameras
3D optical scanning
upper limb anatomy
automatic point cloud alignment
neural network
title Automatic Multiview Alignment of RGB-D Range Maps of Upper Limb Anatomy
title_full Automatic Multiview Alignment of RGB-D Range Maps of Upper Limb Anatomy
title_fullStr Automatic Multiview Alignment of RGB-D Range Maps of Upper Limb Anatomy
title_full_unstemmed Automatic Multiview Alignment of RGB-D Range Maps of Upper Limb Anatomy
title_short Automatic Multiview Alignment of RGB-D Range Maps of Upper Limb Anatomy
title_sort automatic multiview alignment of rgb d range maps of upper limb anatomy
topic depth cameras
3D optical scanning
upper limb anatomy
automatic point cloud alignment
neural network
url https://www.mdpi.com/1424-8220/23/18/7841
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