A Surface-Based Spatial Registration Method Based on Sense Three-Dimensional Scanner.

Background: Three-dimensional (3D) scanners have made it possible to measure and display body surface and shape with high precision. These are fast measurements with minimum discomfort, which is especially useful when children are involved. The objective was to assess the reliability and validity of a 3D-scanner for measuring unconventional torso parameters in children and adolescents. Methods: This is a sub-sample of the SAYCARE study, an observational multicentre research effort being conducted in six South American countries, aimed at developing methods to collect data on cardiovascular health biomarkers, lifestyles, and environmental, social and family risk factors. Images were captured using a portable scanner (iSense, Cubify, USA) attached to a Tablet 128Gb with OSX (Ipad-Air Apple, USA). Images were reshaped to exclude head, hair, arms and legs; area and volume were measured using 3D design software ((Rhinoceros for OSX, v5.02, USA). Results: The sub-sample for our study comprised 54 girls and 46 boys, aged 6 to 17 years old, from two private schools in Lima, Peru. Out of 100 participants, 82 were scanned twice. There was strong reliability (rho_c> 0.80) between first and second measurements of area and volume in boys of every age group. In girls, the reliability coefficient was moderate (rho_c> 0.70) only for area comparison in adolescents older than 10 years of age. The mean torso area was 0.55 m2 (SD 0.08) in girls and 0.63 m2 (SD 0.13) in boys. The overall mean torso volume was 24.4 l (SD 5.33) in girls and 31.47 l (SD 10.14) in boys. Area under ROC curve oscillates between 0.5707 and 0.6383 when volume/area ratio was compared to the selected “gold standard” (waist to height ratio > 0.5). Conclusion: Use of portable and low cost 3D-scanners provides a reliable but inaccurate alternative for area and volume torso measurements in children and adolescents.

Current markerless registration methods for neurosurgical robotics use the facial surface to match the robot space with the image space, and acquisition of the facial surface usually requires manual interaction and constrains the patient to a supine position. To overcome these drawbacks, we propose a registration method that is automatic and does not constrain patient position. An optical camera attached to the robot end effector captures images around the patient's head from multiple views. Then, high coverage of the head surface is reconstructed from the images through multi-view stereo vision. Since the acquired head surface point cloud contains color information, a specific mark that is manually drawn on the patient's head prior to the capture procedure can be extracted to automatically accomplish coarse registration rather than using facial anatomic landmarks. Then, fine registration is achieved by registering the high coverage of the head surface without relying solely on the facial region, thus eliminating patient position constraints. The head surface was acquired by the camera with a good repeatability accuracy. The average target registration error of 8 different patient positions measured with targets inside a head phantom was [Formula: see text], while the mean surface registration error was [Formula: see text]. The method proposed in this paper achieves automatic markerless registration in multiple patient positions and guarantees registration accuracy inside the head. This method provides a new approach for establishing the spatial relationship between the image space and the robot space.

Background: 3D scanners are used to obtain three-dimensional (3D) shapes of body parts, offering an alternative to conventional techniques such as casting and a variety of potential advantages. However, 3D scanners are usually very expensive and not affordable and accessible for most orthotists and prosthetists, especially in developing countries. Therefore, this study aimed to evaluate the validity and reliability of a low-cost handheld and affordable 3D scanner (3Dsystems, ‘sense’) for use in orthotics and prosthetics. Methods: The validity and reliability of the 3D Sense scanner were assessed through repeated scanning and measurement of the predefined circumferences of the stumps of four transtibial amputees and 8 body cast models. Two assessors performed digital scanning and tape measurement on two different days, each consisting of three trials per condition/day. The reliability of the 3D sense scanner was assessed by investigating between trials, the assessors, and day reliability using Intraclass Correlation Coefficients. The standard error of measurement (SEM) was also calculated to assess measurement error. The validity of the 3D sense scanner was assessed using correlation analysis, mean percentage error (the mean differences between scanner and tape measure), and Bland-Altman statistics. Results: The 3D Sense scanner provides stumps and body cast model measurements with similar reliability to the tape measure. Reliability coefficients for the 3D scanner are relatively high (ICC). The ICCs all are near 1.0 and SEMs all range from 0.06 to 0.10. The 3D Sense scanner demonstrated excellent validity. There was a significant positive correlation between the 3D scanner and tape measure for both stumps and body cast models measurements (r > 0.850; p < 0.0001). The measurement error between the 3D scanner and tape measure is very low as indicated by mean differences close to zero. Conclusions: This study introduces a low-cost handheld and affordable 3D scanner, which has proven to be a valid and reliable clinical tool in orthotics and prosthetics. This 3D scanner would have extensive and powerful clinical applicability resulting in valid and reliable digital information of body segments for computer-aided design (CAD) of orthotics and prosthetics.

Our aim was to evaluate the effect of a vacuum bell (VB) combined with a three-dimensional (3D) scanner for the noninvasive treatment of pectus excavatum (PE). A VB was used to create a vacuum at the anterior chest wall with a patient-activated hand pump, and it should be applied regularly for more than 2h each day at home. Eighty-two patients required to be followed up every three months were included in this retrospective study and distributed into four stages (stage 1: treated for 3months, stage 2: treated for 6months, stage 3: treated for 9months, and stage 4: treated for 12months). In addition, the deformity in the chest wall was scanned by a 3D scanner at the clinic, and the 3D depth (3D-DE) and 3D Haller index (3D-HI) of PE were calculated through Geomagic studio 2013 software. Eighty-two patients (12/2017-12/2019) met the criteria at the clinic, and 24 patients (29.3%) achieved excellent correction (3D-DE ≤ 3mm). When comparing the improvement in 3D-DE and 3D-HI of PE to the patient's treatment time, a statistically significant difference was observed between stages 2 and 1 (3D-DE p<0.01, 3D-HI p<0.01), stages 3 and 2 (3D-DE p<0.01, 3D-HI p<0.01) and stages 4 and 3 (3D-DE p<0.01, 3D-HI p<0.01). There was a statistically significant difference in sternum elevation between patients aged <10years and those aged ≥ 10years (3D-DE p = 0.006, 3D-HI p = 0.045) and patients with symmetrical and asymmetric PE (3D-DE p = 0.042, 3D-HI p = 0.032). However, there was no statistically significant difference in sternal elevation between males and females (3D-DE p = 0.27, 3D-HI p = 0.495). The main side effects were moderate subcutaneous hematoma, petechial bleeding, thoracalgia and chest tightness. With controllable side effects, noninvasive treatment for PE with a VB combined with a 3D scanner is safe, objective and radiation free, and the initial results to date are encouraging. Patients aged <10years, with symmetrical PE and treated for over 12months may achieve a better outcome.

Three-dimensional scanners have been widely applied in image-guided surgery (IGS) given its potential to solve the image-to-patient registration problem. How to perform a reliable calibration between a 3D scanner and an external tracker is especially important for these applications. This study proposes a novel method for calibrating the extrinsic parameters of a 3D scanner in the coordinate system of an optical tracker. We bound an optical marker to a 3D scanner and designed a specified 3D benchmark for calibration. We then proposed a two-step calibration method based on the pointset registration technique and nonlinear optimization algorithm to obtain the extrinsic matrix of the 3D scanner. We applied repeat scan registration error (RSRE) as the cost function in the optimization process. Subsequently, we evaluated the performance of the proposed method on a recaptured verification dataset through RSRE and Chamfer distance (CD). In comparison with the calibration method based on 2D checkerboard, the proposed method achieved a lower RSRE (1.73 mm vs. 2.10, 1.94, and 1.83 mm) and CD (2.83 mm vs. 3.98, 3.46, and 3.17 mm). We also constructed a surgical navigation system to further explore the application of the tracked 3D scanner in image-to-patient registration. We conducted a phantom study to verify the accuracy of the proposed method and analyze the relationship between the calibration accuracy and the target registration error (TRE). The proposed scanner-based image-to-patient registration method was also compared with the fiducial-based method, and TRE and operation time (OT) were used to evaluate the registration results. The proposed registration method achieved an improved registration efficiency (50.72 ± 6.04 vs. 212.97 ± 15.91 s in the head phantom study). Although the TRE of the proposed registration method met the clinical requirements, its accuracy was lower than that of the fiducial-based registration method (1.79 ± 0.17 mm vs. 0.92 ± 0.16 mm in the head phantom study). We summarized and analyzed the limitations of the scanner-based image-to-patient registration method and discussed its possible development.

Cranial shapes of Japanese preterm infants at one month of age using a three-dimensional scanner

The growth and development of a person's body can be affected by various factors such as hereditary factors, the environment and the type of food consumed. One method that can be used to find out the condition of a person's body growth and development is to compare weight and height. This analysis is known as Body Mass Index (BMI). To carry out this analysis, weight and height measurements must first be taken. With the tools developed in this study, the analysis process can be carried out easily. This developed tool is able to measure height and weight at the same time. Height measurement is carried out by placing the weight sensor (Load Cell) under the user's footing like a tire scale in general. As for height measurement, on the top of the patient's head, a laser-based distance sensor VL53L1X placed. In contrast to height measurement which uses a voice-based distance sensor with direct measurements on the surface of the patient's head whose measurement results are less accurate. This is due to the uneven surface of the head, different hair shapes, and diffused sound waves. With the Scale Bar method/plate that can move up/down automatically as the sensor measurement plane. Thus, the measurement results are better because the reflection plane is in the form of a flat plate so that the light reflection results from the laser sensor become more focused. From the results of measurements, weight and height in several patients, the results of measurements were obtained with an average difference of 0.3 cm for height and 0.09 kg for body weight measurement.

OBJECTIVE To compare the registration accuracy of three-dimensional (3D) facial scans for the design of full-arch implant supported restoration by five methods and to explore the suitable registration method. METHODS According to the criteria, ten patients with maxillary edentulous jaw or end-stage dentition requiring implant supported restorations were enrolled in this study. A special rim with individual feature marks reflected appropriate occlusal relationship and esthetic characteristics was made for each patient. Both 3D facial scan data of natural laughter and with opener traction to expose the teeth or occlusal rim of each patient were acquired by facial scan and input to the digital analysis software Geomagic Qualify 2012. The dataset was superimposed by five different methods: seven facial anatomical landmark points alignment, facial immobile area alignment (forehead and nasal area), facial anatomical landmark points and immobile area combining alignment, facial feature points alignment, facial and intraoral feature points alignment with the same local coordinate system. The three-dimensional deviation of the same selected area was calculated, the smaller the deviation, the higher the registration accuracy. The 3D deviation was compared among the three registration methods of facial anatomical landmark points, facial immobile area alignment and the combination of the above two methods. Friedman test was performed to analyze the difference among the three methods (α=0.05). The effect of the aid of the facial and intraoral feature points were evaluated. Paired t test were performed to analyze the difference (P<0.05). RESULTS The average three-dimensional deviation of the selected area after alignment with the facial anatomical landmarks was (1.501 2±0.406 1) mm, significantly larger than that of the facial immobile area best-fit alignment [(0.629 1±0.150 6) mm] and the combination of the two methods[(0.629 1±0.150 6) mm] (P < 0.001). The aid of the facial feature points could significantly reduce the deviation (t=1.001 3, P < 0.001). There was no significant statistical difference in the remaining groups. CONCLUSION The forehead area of the 3D facial scan can be exposed as much as possible. The establishment of facial characteristic landmark points and the use of the invariant area alignment can improve the accuracy of registration. It should be clinically feasible to apply three-dimensional facial scan to the design of full-arch implant supported restoration with the registration of the immobile area on the face especially the forehead area.

Use of additive manufacturing is growing rapidly in the orthotics field. This technology allows orthotics to be designed directly on digital scans of limbs. However, little information is available about scanners and 3D scans. The aim of this study is to look at the agreement between manual measurements, high-level and low-cost handheld 3D scanners. We took two manual measurements and three 3D scans with each scanner from 14 lower limbs. The lower limbs were divided into 17 sections of 30mm each from 180mm above the mid-patella to 300mm below. Time to record and to process the three 3D scans for scanners methods were compared with Student t-test while Bland-Altman plots were used to study agreement between circumferences of each section from the three methods. The record time was 97s shorter with high-level scanner than with the low-cost (p = .02) while the process time was nine times quicker with the low-cost scanner (p < .01). An overestimation of 2.5mm was found in high-level scanner compared to manual measurement, but with a better repeatability between measurements. The low-cost scanner tended to overestimate the circumferences from 0.1% to 1.5%, overestimation being greater for smaller circumferences. In conclusion, 3D scanners provide more information about the shape of the lower limb, but the reliability depends on the 3D scanner and the size of the scanned segment. Low-cost scanners could be useful for clinicians because of the simple and fast process, but attention should be focused on accuracy, which depends on the scanned body segment.

Point-pair registration is widely used in an image-guided neurosurgery system. Poor distribution of the fiducial points leads to an increase in the target registration error (TRE). This study aimed to provide templates consisting of optimized positioning of the fiducial points to reduce the TRE in image-guided neurosurgery. We divided the head into 6 regions and provided distribution templates of the fiducial points for each of them. A variable termed TREM(r) was used to express the approximate expected square of the TRE at the target point with a specified distribution of fiducial points. We randomly selected 85 patients from 5 hospitals who underwent image-guided neurosurgery and compared the TREM(r) of the real fiducial points with that of the templates. We grouped the patients by hospitals and regions. The mean TREM(r)s of the templates were much smaller than those of the real fiducial points. In each group, the range of the TREM(r) values of the templates was much smaller than that of the real fiducial points. This study provides an easy method to implement a good distribution of the fiducial points to help reduce TRE in image-guided neurosurgery. The templates are simple and exact and can be easily integrated into current workflow.

Three-Dimensional scanning is a method to convert various distances set into object visualization in 3-dimensional form. Developing a 3D scanner has various methods and techniques depending on the 3d scanner's purpose and the size of the object target. This research aims to build a prototype of a 3D scanner scanning small objects with dimensions maximum(10x7x23)cm. The study applied an a-three dimensional(3D) scanner using infrared and a motor to move the infrared upward to get Z-ordinate. The infrared is used to scan an object and visualize the result based on distance measurement by infrared. At the same time, the motor for rotating objects gets the (X, Y) ordinates. The object was placed in the center of the scanner, and the maximum distance of the object from infrared was 20cm. The model uses infrared to measure the object's distance, collect the result for each object's height, and visualize it in the graphic user interface. In this research, we tested the scanner with the distance between the object and infrared were 7 cm, 10 cm, 15 cm, and 20 cm. The best result was 80% accurate, with the distance between the object and the infrared being 10cm. The best result was obtained when the scanner was used on a cylindrical object and an object made of a non-glossy material. The design of this study is not recommended for objects with edge points and metal material.

In order to design the indoor internet of things (IoT) applications such as smart buildings, it is crucial to understand the propagation characteristics of the indoor environments. To this end, we implement the three-dimensional (3D) scanner with the size of 1.5 × 1.5 × 1.5 m (movable range of approximately 1.3 × 1.3 × 1.3 m). We can obtain the multipath fading variation precisely within the 3D scanner. We present the received signal strength indicator (RSSI) measurement results employing LoRa modules in the magnetic shield room. The measurement results indicate its accurate measurements and effectiveness of the implemented 3D scanner for multipath fading.

Imagery-based 3D scanning can be performed by scanners with multiple form factors, ranging from small and inexpensive scanners requiring manual movement around a stationary object to large freestanding (nearly) instantaneous units. Small mobile units are problematic for use in scanning living creatures, which may be unwilling or unable to (or for the very young and animals, unaware of the need to) hold a fixed position for an extended period of time. Alternately, very high cost scanners that can capture a complete scan within a few seconds are available, but they are cost prohibitive for some applications. This paper seeks to assess the performance of a large, low-cost 3D scanner, presented in prior work, which is able to concurrently capture imagery from all around an object. It provides the capabilities of the large, freestanding units at a price point akin to the smaller, mobile ones. This allows access to 3D scanning technology (particularly for applications requiring instantaneous imaging) at a lower cost. Problematically, prior analysis of the scanner’s performance was extremely limited. This paper characterizes the efficacy of the scanner for scanning both inanimate objects and humans. Given the importance of lighting to visible light scanning systems, the scanner’s performance under multiple lighting configurations is evaluated, characterizing its sensitivity to lighting design.

To describe the use of the mastoid skull post of a surgical image guidance system for image guided surgery and intraoperative navigation of the nasopharynx. This adaptation overcomes the limitations of a headset frame or head clamp and can be applied to open and closed surgery of the nasal cavities, sinuses, orbits, midface and anterior skull base. A sterile mastoid skull post of a surgical image guidance system was securely screwed into the outer table of the frontal bone and a passive reference frame fixed to it. The position of the reference frame relative to the patient's head remained constant during surgery. Between August 2002 and November 2006, 22 patients underwent a surgical nasopharyngectomy using an image guidance system and frontal bone skull post. No surgical complications or complications of the frontal bone skull post occurred. Using the skull post of a surgical image guidance system anchored to the frontal bone to carry a passive reference frame provides real-time visual information about the relationship of relevant anatomy to the surgical field on a fully mobile head in open or closed procedures of the midface and anterior skull base while accuracy and sterility are maintained.

We propose a measuring method of shear deformation in drape using three-dimensional (3D) scanning. We measured the local shear angles in fabric drape based on the Fabric Research Laboratories (FRL) drape test for woven fabrics using the proposed method. We investigate the effects of the relative positions of the node to the center grainlines that cross at the fabric center, and the bending and shear properties of fabric on the shear angles. To measure the local shear deformation, we obtained 3D drape shapes of four different fabrics with three to six nodes. We covered the obtained drape shapes using a fabric model composed of square cells that allowed shear deformation. By calculating the shear angles of the cells, we obtained the local shear deformation. We found that the FRL drape can be characterized by three areas, except for the flat areas of the support disks: (a) areas along the center grainlines with zero or small shear angles within 3°, which could result from single curvature bending; (b) areas in the bias directions with relatively large shear angles over 3°, which could result from double curvature bending; and (c) polygon edges connected by tangents of the support disk with relatively larger shear angles than their surroundings, which could result from both bending and shear deformation, such as folding and wrinkles. By investigating the relationships between areas with large shear angles and the bending rigidity/shear stiffness, we clarified that the bending rigidity indirectly affects the local shear deformation of drape.