Plane Parameters Research Articles

Analyzing the error of Computed Tomography-based pore detection by using microscope images of matched cross-sections

Pore detection by x-ray computed tomography (CT) is widely used for additively manufactured (AM) parts. The ability of a CT device to reliably detect pores of a certain shape and size is still being investigated, though. Typical methods to evaluate the error of CT-based pore detection utilize reference objects or microscope images of cross-sections. This work improves the cross-section method by directly matching the two-dimensional (2D) plane depicted in the microscope image to the corresponding plane within the three-dimensional (3D) scan. For this purpose, a specially designed test part was scanned for a first time before preparing a cross-section and a second time afterward. The test part's design allowed to identify the cross-section's plane parameters relative to the part's local coordinate system in the second scan. The plane parameters were then transferred to the first CT scan in which pores had been detected to identify voxels that lay within the plane that was to become the cross-section. An image was extracted from this plane that directly matched a microscope image of the cross-section. Comparing CT and microscope images highlighted that CT's relative lack of resolution may lead to relevant errors when analyzing pore area and pore form.

3D layout estimation of general rooms based on ordinal semantic segmentation

AbstractRoom layout estimation aims to predict the location and range of layout planes of interior spaces. Previous works treat each layout plane as an independent individual without considering the ordinal relation between walls, resulting the loss of the wall planes and the lack of integrity. This paper proposes a novel two‐branch neural networks model to estimate 3D layouts of cuboid and non‐cuboid room types. The model embeds the ordinal relation between layout planes into the layout segmentation branch through an proposed ordinal classification loss function, and outputs both pixel‐level layout segmentation maps and layout plane parameter maps. Then, the instance‐level plane parameters of each layout plane are determined by using an instance‐aware pooling layer. Finally, the sharpness of layout edges of the 2D layout semantic segmentation map is optimized by using an improved depth map intersection algorithm. Furthermore, we annotate a large‐scale 3D room layout estimation dataset, InteriorNet‐Layout, to obtain a steady model. Experiments on synthesized real‐world datasets show that the proposed method achieves faster calculation while maintaining high accuracy. Code is available at https://github.com/Hui‐Yao/3D‐ordinal‐layout‐estimation.

Characteristics and factors associated with the position of the haptic after ICL V4C implantation.

To assess the position of implantable collamer lens (ICL) haptic after ICL V4C implantation using standardized panoramic ultrasound bimicroscopy (UBM), to analyze its characteristics, associated factors, and the relationship with the clinical vault quantitatively. Hankou Aier Eye Hospital, Wuhan, Hubei, China. Cross-sectional study. 167 subjects (323 eyes) implanted with ICL V4C who had a 3-month follow-up with UBM examination were included in this study. The relative position of ICL to the adjacent structure and ICL haptic-related parameters (the final tip point of ICL haptic [ftICL haptic], measured from the scleral spur to the final tip of the ICL haptic, the posterior of the ICL to ICL haptic [ICL arc], measured from the posterior surface of the ICL to the ICL haptic plane, and the height of the crystalline lens from the ICL haptic (lens arc), measured from the anterior surface of the crystalline lens to the ICL haptic plane and other parameters), were estimated on the UBM image. Eyes were divided into 3 subgroups according to the ftICL haptic (Group 1: ≤0.5 mm; Group 2: 0.5 to 1.0 mm; and Group 3:≥1.0 mm, respectively), and the factors associated with the ICL haptic-related parameters and their impact on the clinical vault were evaluated. The haptics could be imaged in the ciliary sulcus, on the ciliary body, and under the ciliary body in 629 (48.7%), 525 (40.6%), and 138 (10.7%) eyes, respectively. The ftICL haptic and the summation of ICL arc and lens arc showed a correlation with the clinical vault ( r = -0.34, P = .00; r = 0.87, P = .00). When the ftICL haptic results were divided into 3 groups, the percentage of eyes that exhibited clinical vault >750 μm were lowest in Group 3. Multivariate regression analysis showed spherical equivalent, white-to-white (WTW), anterior chamber volume (ACV) and iris-ciliary angle (ICA); the difference between the implanted ICL size and horizontal sulcus-to-sulcus (ICL size-STS) were associated with the ftICL haptic. The IOP, WTW, ACV, and the ICL size-STS were significantly associated with ICL arc, while the ICA and lens rise were associated with lens arc. The position of ICL haptic was associated with the clinical vault. Its quantitative evaluation may provide valuable information to help clinicians to select the best ICL size before surgery and understand the formation of clinical vault after surgery.

The top 100 most-cited articles on adult spinal deformity: The most popular topics are still sagittal plane parameters and complications.

This study aimed to summarize the characteristics of the 100 most-cited articles on adult spinal deformity (ASD) and to analyze past and current research hotspots and trends. Literature searches (from inception to 28 April 2022) using Web of Science databases were conducted to identify ASD-related articles. The top 100 most-cited articles were collected for further analysis. Meanwhile, author keywords from articles published in the last 5 years were selected for further analysis. The top 100 most-cited articles on ASD were selected from 3,354 papers. The publication year ranged from 1979 to 2017, and all papers were written in English. The citation count among them ranged from 100 to 1,145, and the mean citation number was 215.2. The foremost productive first author was Schwab F. University of Washington had the largest number of publications. The United States of America had the largest number of published articles (n = 84) in this field. Spine was the most popular journal. Complications were the most studied themes. The visualization analysis of author keywords from the literature in the recent 5 years showed that complications, sagittal plane parameters, and surgical techniques are still the research hotspots, and minimally invasive surgery will continue to develop rapidly. Based on a comparative analysis of the results of bibliometric and visualization, complications and sagittal plane parameters are still the major topics of research at present and even later, and minimally invasive surgery has a growth trend in this field of ASD.

Fatigue life prediction for notched specimen considering modified critical plane method

AbstractTo meet the different functional requirements of the components, irregularities and geometric discontinuities occur in the structural design of the components. These geometrical discontinuities lead to local stress concentrations, which inevitably introduce notch effects. The unyielding internal material still supports the high‐stress area on the plane due to the supporting effect of the notch. This effect can lead to inaccurate prediction of fatigue life. So, the notch support factor and strain were used as damage parameters to modify the life prediction model of the notched specimens in this research. And an improved critical plane method is applied in selecting damaged planes. It considers the damage at the notch before loading and uses dynamic weights to measure the effect of the maximum stress plane on the damaged plane. The model was validated using TC4 and GH4169 notch data and compared with other models, and the revised model has higher accuracy. The damaged plane and damage parameters to modify the fatigue life of the notched specimen make more physical sense and are more consistent with the fatigue failure mechanism.

Canadian Spine Society

# Abstract 57. Radiographic reporting in adolescent idiopathic scoliosis: Is there a discrepancy comparing radiologists’ reports and surgeons’ assessments? {#article-title-2} Cobb angle measurement is the standard method for quantification of scoliosis in adolescent idiopathic scoliosis (AIS),

MULTISENSORY EXPERIENCE IN THE OUTDOOR DESIGN OF TAMAN TRUNOJOYO MALANG

The user's sensory experience of an architecture evokes his emotions. The sensory system is not only limited to the visual aspect, but of course other senses. Human perception is basically multisensory, so that the individual will easily explain experiences through previous environmental interactions. This research was conducted to examine the user's multisensory experience at Taman Trunojoyo regarding the architectural space elements. The method used is descriptive qualitative, data collection using literature study and observation. This study divides the four areas studied and analyzes the architectural elements in terms of visual, haptic, auditory, olfactory and basic orientation aspects. In addition, the application of the parameters of the movement plane, guiding plane and resting plane were also analyzed in each area. The results of this study indicate that Trunojoyo park is not limited to a park that can only be enjoyed visually, but this park provides elements that can provide a multisensory experience to visitors. Such as the facilities of a reflection garden, elements of a fountain and children's playground, and others. However, because of its location in the middle of the city, it causes disturbances such as vehicle noise that enters at several points in the area.

Surgeon and SterEOS agreement of spinal sagittal plane parameters in patients with adolescent idiopathic scoliosis.

To compare agreement between surgeons and sterEOS sagittal plane measurements. EOS radiographs of 74 patients with adolescent idiopathic scoliosis were reviewed. The measurements were generated by two surgeons and compared to sterEOS. Intraclass correlations (ICC) were calculated. Agreement was also analyzed for the following subgroups: Cobb angle < 70° vs ≥ 70°, lumbar modifier A vs B/C, and BMI of < 24.5kg/m2 vs ≥ 24.5kg/m2. Agreement was poor if the ICC was < 0.5, moderate if 0.5-0.75, good if 0.75-0.9, and excellent if > 0.9. Paired t tests were performed to compare the surgeon's and sterEOS means. For the surgeons, agreement was good (0.75-0.89) except for pelvic tilt (PT) and sacral slope (SS), which were excellent (0.91-0.92). Agreement between the surgeons and sterEOS were good (0.78-0.9) except PT and SS, which were excellent (0.91-0.93). Agreement was negatively affected for T4-T12 kyphosis, PI, and SS in the ≥ 70°group, LL when BMI was ≥ 24.5kg/m2, and LL, PI, and SS in the lumbar modifier B/C group. The ICCs overlapped with the 95% confidence intervals (95% CI). Paired t-test showed a significant difference for T4-T12 kyphosis (p < 0.001). This was also true in the < 70° group (p < 0.001), the ≥ 70° group (p = 0.04), and the BMI < 24.5kg/m2 group. PT was significantly different for the ≥ 70° group. There was good to excellent agreement between the surgeons and surgeons and sterEOS. Some variables may affect agreement. The surgeons overestimated T4-T12 kyphosis.

Intelligent identification of rock mass structural plane and stability analysis of rock slope block

The blocking problem caused by structural plane cutting is often the primary problem in evaluating the stability of rock mass engineering. The geometric parameters of the block structural plane are important research bases for analyzing block stability. In order to solve the problems of low efficiency, heavy workload, and high subjectivity in the traditional acquisition of structural plane occurrence information, taking the slope at the entrance of Suichang Gold Mine National Mine Park as the research background, this paper studies the rapid extraction method of structural plane information based on three-dimensional laser scanning data, and puts forward the process and data processing method of using a 3D laser scanner to collect slope block structural information to obtain point cloud data. Based on the coordinate projection principle and MATLAB, the rock slope block stability analysis CPG program was developed, which realized the whole process from data acquisition to block stability analysis. The research results are essential for identifying structural plane and block stability analysis and can provide theoretical and technical support for practical engineering applications.

Sigma-FP: Robot Mapping of 3D Floor Plans With an RGB-D Camera Under Uncertainty

This letter presents Sigma-FP, a novel 3D reconstruction method to obtain the floor plan of a multi-room environment from a sequence of RGB-D images captured by a wheeled mobile robot. For each input image, the planar patches of visible walls are extracted and subsequently characterized by a multivariate Gaussian distribution in the convenient Plane Parameter Space. Then, accounting for the probabilistic nature of the robot localization, we transform and combine the planar patches from the camera frame into a 3D global model, where the planar patches include both the plane estimation uncertainty and the propagation of the robot pose uncertainty. Additionally, processing depth data, we detect openings (doors and windows) in the wall, which are also incorporated in the 3D global model to provide a more realistic representation. Experimental results, in both real-world and synthetic environments, demonstrate that our method outperforms state-of-the-art methods, both in time and accuracy, while just relying on Atlanta world assumption.

Automatic interpretation of structural plane parameters in borehole camera images from drilling engineering using MOORA method

Automatic interpretation of structural plane parameters in borehole camera images from drilling engineering using MOORA method

Concave apical translation with simultaneous convex apical derotation technique in adolescent idiopathic scoliosis Surgery: A technical note and case series

ObjectiveThere is still a debate regarding the efficacy of pedicle screws in adolescent idiopathic scoliosis (AIS) surgery. As well as the implant being used, the surgeon factor and the correction technique are also important for correction quality. The purpose of this study was to introduce the concave apical translation with simultaneous convex apical derotation technique (CATCAD) using polyaxial pedicle screws and report the radiographical outcomes. Material and MethodsConsecutive AIS patients who had been scheduled for surgery were enrolled in the study. The preoperative and postoperative radiographic parameters included Cobb angle, apical vertebral translation (AVT), thoracic kyphosis (TK) and apical vertebral rotation (AVR). Coronal plane parameters were measured in plain radiography. Sagittal and axial plane parameters were measured in computed tomography scan (CT scan). Implant density was calculated. ResultsTwenty patients were included in the study. All were female with a mean age of 14.9 years. Eighteen patients were either Lenke 1 (45.0 %) or Lenke 2 (45.0 %). The remaining patients were Lenke 3 and 4 (10.0 %). There was an improvement of postoperative radiographic parameters. The mean of AVR corrections were −1.8 ± 2.8° (10.0 %) and −4.5 ± 2.8° (24.0 %) for lower apical screw density (LAD) group and higher apical screw density (HAD) group, respectively (p-value = 0.024). ConclusionCATCAD technique can achieve the 3D correction in AIS surgery. With this correction technique, the AVR correction seem higher if the high apical screw density implant is used.

Study on size effect of jointed rock mass and influencing factors of the REV size based on the SRM method

Based on the Yaojiayu tunnel of Binlai Expressway, the size effect of jointed rock mass and influencing factors of the representative elementary volume (REV) were studied. The point cloud image of jointed rock mass near the tunnel face was collected by 3D laser scanning technology. Through the Geology Plane software independently developed by Shandong University, the structural plane data were processed and obtained. According to the structural plane data, the discrete fracture network (DFN) was established. Based on the laboratory test results of rock samples in the tunnel site, the particles were embedded into DFN to construct the synthetic rock mass (SRM). The size effect and REV of the jointed rock mass were studied based on the uniaxial compressive strength (UCS) and Young's modulus obtained by uniaxial compression test simulations. It is concluded that the REV size of the jointed rock mass is 7 m × 7 m × 14 m, which provides the criterion and calculation parameters for simulating tunnel excavation in jointed rock mass by the continuous deformation calculation method. In order to study the influence of joint geometric parameters (trace length, spacing, and dip angle) on REV size, different multi-scale SRM models were established by changing the parameters of structural planes. It is observed that within a certain size range, the REV size is negatively correlated with the joint trace length and dip angle, while positively correlated with the joint spacing. And the size of REV is gradually stable with the increase of geometric parameters of joints. Based on the influence law of joint geometry parameters on REV, the REV size range of different engineering can be estimated approximately.

Geometric Calibration of Single-Pixel Distance Sensors

Single-pixel distance sensors are a low-power, low-cost option for distance ranging, and are often attached to robots for collision detection and avoidance. The relative sensor pose, i.e., its position and orientation relative to the robot, must be known to relate its measurements to 3D scene geometry. However, sensor pose is difficult to measure accurately, which has precluded the use of single-pixel sensors from applications such as environment mapping and precise collision avoidance. In this work, we provide a calibration procedure that can accurately determine the pose of a single-pixel distance sensor given only the known motion of the robot and an unknown planar target. We establish a geometric relationship between the relative sensor pose, robot motion, and an arbitrary plane, and show that the plane and sensor parameters can be recovered via nonlinear optimization. The result is a practical procedure for sensor calibration. We evaluate the procedure in simulation and in real world experiments, and provide an open source implementation. We consider two commonly available sensors (ST VL6180X and ST VL53L3CX) and characterize them to show that while they deviate from the idealized model used in our derivation, their poses can be recovered precisely and used for effective 3D scene reconstruction.

Discrimination of Microseismic Events in Coal Mine Using Multifractal Method and Moment Tensor Inversion

Discrimination of various microseismic (MS) events induced by blasting and mining in coal mines is significant for the evaluation and forecasting of rock bursts. In this paper, multifractal and moment tensor inversion methods were used to investigate the waveform characteristics and focal mechanisms of different MS events in a more quantitative way. The multifractal spectrum calculation results indicate that the three types of MS waveform have different distribution ranges in the multifractal parameters of ∆α and Δf(α). The results show that the blasting schemes also have a great influence on MS waveform characteristics. Consequently, the multifractal parameters of ∆α and Δf(α) can be used to discriminate different MS events. Further, the focal mechanisms of MS events were calculated by seismic moment tensor inversion. The results show that an explosion is not the dominant mechanism of deep-hole blasting MS events, and the CLVD and DC components account for an important proportion, indicating that some additional processes occur during blasting. Moreover, the coal-rock fracture MS events are characterized by compression implosion or compression/shear implosion mixed focal mechanisms, while the overburden movement MS events are tensile explosion or tensile/shear explosion mixed focal mechanisms. The focal mechanisms and nodal plane parameters have close relationships with the inducing factors and occurrence processes of MS events.

TLS-Detectable Plane Changes for Deformation Monitoring.

TLS is nowadays often used for deformation monitoring. As it is not able to scan identical points in different time epochs, mathematical models of objects derived from point clouds have to be used. The most common geometric form to describe built objects is a plane, which can be described by four parameters. In this study, we aimed to find out how small changes in the parameters of the plane can be detected by TLS. We aimed to eliminate all possible factors that influence the scanning. Then, we shifted and tilted a finite physical representation of a plane in a controlled way. After each controlled change, the board was scanned several times and the parameters of the plane were calculated. We used two different types of scanning devices and compared their performance. The changes in the plane parameters were compared with the actual change values and statistically tested. The results show that TLS detects shifts in the millimetre range and tilts of 150″ (for a 1 m plane). A robotic total station can achieve twice the precision of TLS despite lower density and slower performance. For deformation monitoring, we strongly recommend repeating each scan several times (i) to check for gross errors and (ii) to obtain a realistic precision estimate.

Improvement of the sagittal alignment of the spine in patients with achondroplasia after subtrochanteric femoral lengthening.

Limb-lengthening surgery to treat short stature has undergone great development in recent years with the use of intramedullary telescopic nails (TIMNs). A limited number of studies have explored the impact of lower limb lengthening on the spine, though their conclusions are not consistent. The aim of this research is to analyze changes in spinopelvic sagittal alignment and balance after lower limb lengthening in achondroplastic patients. Prospective study of patients with achondroplasia treated with bilateral femoral lengthening using an TIMN. Different sagittal spinal and pelvic plane parameters were measured on pre- and 2year postoperative lateral spine radiographs: cervical lordosis, thoracic kyphosis, TL junction, lumbar lordosis (LL), pelvic incidence, pelvic tilt (PT), sacral slope (SS), and sagittal vertebral axis (SVA). Similarly, information regarding the elongation procedure was recorded. A total of 10 patients were included (60% male), with a median age of 13.39 (2.32) years at first surgery and a median height of 120.3 (5.75) cm. A 10cm elongation was performed in all patients through femoral subtrochanteric osteotomy. Statistically significant changes were found in LL -15.2 (7.4-17.9)º (p = 0.028), PT 11.7 (10.3-13.4)º (p = 0.018), SS -11.6 (-13.4 to -10.4)º (p = 0.018) and |SVA| -34.3 (-39.10 to -1.7) mm (p = 0.043). Bilateral lower limb lengthening in patients with achondroplasia not only increases their size, but also improves sagittal spinopelvic alignment and balance. This may be due to retroversion of the pelvis and subsequent decrease in SS and LL as a result of the increased tightness of the gluteus maximus and hamstring muscles after femoral lengthening through subtrochanteric osteotomy. II, prospective comparative cohort study, before and after intervention.

The effect of porosity size and oxidation on the HCF property of nickel-based single crystal superalloy at 980 ℃

The high-cycle fatigue (HCF) lives and fatigue limits of nickel-based single crystal superalloys (NBSX) with different porosity sizes were investigated at 980 °C. The test results show that the failure cracks prone to initiate from large internal pores, and the HCF properties are mainly controlled by the critical pore size. However, when the stress is close to the fatigue limit, the secondary cracks will initiate from the oxide layer obviously, which will further weaken the HCF properties. Therefore, a life prediction model based on the critical plane parameter and oxidation kinetic equation was proposed to evaluate the effect of porosity size and oxidation on the HCF life of NBSX. Then, combing the life prediction model and Murakami model, a fatigue limit evaluation model was presented. Compared with test results, the life prediction model and fatigue limit evaluation model are accurate and effective. Finally, the defect-tolerance analysis was carried out by the Kitagawa-Takahashi diagram, which could be a visual guide for the anti-fatigue design of NBSX.

Spatiotemporal Calibration of Camera-LiDAR Using Nonlinear Angular Constraints on Multiplanar Target

The combinations of data captured from diverse sensors can yield reliable geometric and semantic information. However, calibration process must be preceded to make use of combined data. Calibration methods are classified by the adjusted parameters. Spatial calibration, which merges data to a single spatial reference frame, adjusts spatial parameters. Moreover, temporal offset parameter must be adjusted for sensors to acquire data under dynamic conditions, which is known as temporal calibration. In this study, a novel constraint adjustment method was proposed for spatiotemporal calibration, which combines mobile light detection and ranging (LiDAR) sensor with visual camera. It estimates seven parameters–three lever arm parameters, three bore-sight parameters, and temporal offset parameter–simultaneously. A nearly orthogonal multiplanar chessboard target was built for nonlinear angular constraints. B-spline interpolation method was employed to interpolate the plane parameters obtained from the camera and facilitate estimation of the temporal offset. Additionally, the calibration results were evaluated using correlation values and standard errors of the estimated parameters. The sequential quadratic programming method, which yields robust results for nonlinear optimization problem, was used to optimize a point-to-plane distance model subjected to nonlinear angular constraints. Assorted experiments with different sensor motions were conducted to evaluate the effects of the nonlinear angular constraints. Compared to the results of nonconstrained calibration methods, the results of the proposed method indicate lower correlation values between the calibration parameters, reduced standard errors, and fewer iterations in the optimization process, which validates the superiority of the proposed calibration method.

Investigation on the mapping for temperature-induced responses of a long-span steel truss arch bridge

Temperature-induced bridge responses are highly sensitive to changes in bridge properties. Thus, the relationship between temperature and associated responses can be used as a surrogate to assess the health of bridges. However, the relationship between temperature and temperature-induced displacement is influenced significantly by bridge bearing properties. The temperature variation cannot cause longitudinal displacements until the longitudinal restraint of bearings is overcome. Additionally, the temperature-induced strains highly depend on spatial temperature distributions in bridges. The developed mappings seldom consider the aforementioned issues, resulting in errors that can conceal the variation produced by the changes in bridge conditions. Focusing on long-span steel truss arch bridges with spherical bearings, this study seeks to accurately map the temperature-induced responses considering the bearing properties and spatial temperature distributions. The relationship between temperature variation and temperature-induced responses is explored initially using the elastic beam theory. Subsequently, the mapped relationship is validated using field monitoring data. Results show that the relationship produces unique flat planes in 3 D space; the plane parameters, including the orientation and boundary, are determined by the structural parameters, especially the bridge cross-section properties and bearing properties. Accordingly, the 3 D baseline can provide a feasible signature for bridge conditions.