Effects of Different Parameter Settings for 3D Data Smoothing and Mesh Simplification on Near Real-Time 3D Reconstruction of High Resolution Bioceramic Bone Void Filling Medical Images

Three-dimensional reconstruction plays a vital role in assisting doctors and surgeons in diagnosing the healing progress of bone defects. Common three-dimensional reconstruction methods include surface and volume rendering. As the focus is on the shape of the bone, this study omits the volume rendering methods. Many improvements have been made to surface rendering methods like Marching Cubes and Marching Tetrahedra, but not many on working towards real-time or near real-time surface rendering for large medical images and studying the effects of different parameter settings for the improvements. Hence, this study attempts near real-time surface rendering for large medical images. Different parameter values are experimented on to study their effect on reconstruction accuracy, reconstruction and rendering time, and the number of vertices and faces. The proposed improvement involving three-dimensional data smoothing with convolution kernel Gaussian size 5 and mesh simplification reduction factor of 0.1 is the best parameter value combination for achieving a good balance between high reconstruction accuracy, low total execution time, and a low number of vertices and faces. It has successfully increased reconstruction accuracy by 0.0235%, decreased the total execution time by 69.81%, and decreased the number of vertices and faces by 86.57% and 86.61%, respectively.

Effects of Different Parameter Settings for 3D Data Smoothing and Mesh Simplification on Towards Near Real-Time 3D Reconstruction of High Resolution Bioceramic Bone Void Filling Medical Images

Three-dimensional reconstruction plays an important role in assisting doctors and surgeons in diagnosing bone defects’ healing progress. Common three-dimensional reconstruction methods include surface and volume rendering. As the focus is on the shape of the bone, volume rendering is omitted. Many improvements have been made on surface rendering methods like Marching Cubes and Marching Tetrahedra, but not many on working towards real-time or near real-time surface rendering for large medical images, and studying the effects of different parameter settings for the improvements. Hence, in this study, an attempt towards near real-time surface rendering for large medical images is made. Different parameter values are experimented on to study their effect on reconstruction accuracy, reconstruction and rendering time, and the number of vertices and faces. The proposed improvement involving three-dimensional data smoothing with convolution kernel Gaussian size 0.5 and mesh simplification reduction factor of 0.1, is the best parameter value combination for achieving a good balance between high reconstruction accuracy, low total execution time, and a low number of vertices and faces. It has successfully increased the reconstruction accuracy by 0.0235%, decreased the total execution time by 69.81%, and decreased the number of vertices and faces by 86.57% and 86.61% respectively.

Design Privacy with Analogia Graph

Human vision is often guided by instinctual commonsense such as proportions and contours. In this paper, we explore how to use the proportion as the key knowledge for designing a privacy algorithm that detects human private parts in a 3D scan dataset. The Analogia Graph is introduced to study the proportion of structures. It is a graph-based representation of the proportion knowledge. The intrinsic human proportions are applied to reduce the search space by an order of magnitude. A feature shape template is constructed to match the model data points using Radial Basis Functions in a non-linear regression and the relative measurements of the height and area factors. The method is tested on 100 datasets from CAESAR database. Two surface rendering methods are studied for data privacy: blurring and transparency. It is found that test subjects normally prefer to have the most possible privacy in both rendering methods. However, the subjects adjusted their privacy measurement to a certain degree as they were informed the context of security.

Creating Tactile Educational Materials for the Visually Impaired and Blind Students Using AI Cloud Computing

There are 24.5 million visually impaired and blind (VIB) students who have limited access to educational materials due to cost or availability. Although advancement in technology is prevalent, providing individualized learning using technology remains a challenge without the proper tools or experience. The TacPic system was developed as an online platform to create tactile educational materials (TEM) based on the image inputs of users who do not have prior experience in tactile photo development or 3D printing. The TacPic system allows the users to simply upload images to a website and uses AI cloud computing on the Amazon Web Services platform. First, it segments and labels the images. Then, the text label is converted into braille words. Subsequently, surface rendering and consolidation of the image and text is performed, before it is converted into a single file that is ready for 3D printing. Currently, the types of TEM that can be created are tactile flashcards, tactile maps, and tactile peg puzzles, which can be developed within a few hours. This is in contrast to a development period of weeks using traditional methods. Furthermore, the tactile educational materials were tested by two VIB teachers and six VIB students. It was found that those who are congenitally blind need more time to identify the object and rely more on the braille labels compared to students who became blind at a later age. Teachers also suggested producing TEM that use simpler images, and TEM that are suitable for both sighted and VIB students. In conclusion, the researchers successfully developed a platform that allows more educators or parents to develop personalized and individualized TEM. In the future, further optimization of the algorithms to improve segmentation and the inclusion of other features, such as color, could be undertaken. Finally, new printing materials and methods are needed to improve printing efficiency.

Prenatal Diagnosis and Postnatal Treatment in a Case of Abdominal Obstruction and Polyhydramnios Caused by Amniotic Band Sequence

Background: Amniotic band sequence (ABS) is a rare congenital disorder resulting from the entanglement of fetal parts by fibrous bands that may cause disruptions, deformations, or malformations that can range from mild to life threatening conditions. Prenatal diagnosis is usually based on ultrasounds visualization on amniotic bands attached to fetal parts, possibly causing fetal defects. Case Presentation: A 19-year-old woman with an unremarkable clinical history and a low-risk pregnancy was referred to our Fetal Therapy Unit for a suspected fetal clubfoot at 22 weeks gestational age. A chorioamniotic separation, together with unilateral clubfoot was diagnosed. Due to a high risk of premature rupture of membranes a decision was made not to perform amniocentesis for genetic investigation. At prenatal follow up progressive polyhydramnios developed with a preterm spontaneous rupture of the membranes at 34 weeks. After caesarean section – due to breech presentation – an amniotic band was observed at the abdominal level causing a circular skin lesion, constriction, and a sub-occlusive intestinal status. Moreover, a left clubfoot with amputation of distal phalanx of the second toe and a right foot amputation of 2nd and 3rd toes were evident. The neonate underwent abdominal plastic surgery on the second day of life with complete recovery. Following the postnatal diagnosis of ABS, we re-examined a stored fetal 3D ultrasound volume acquired at 22 weeks and, focusing on the fetal surface rendering, we could notice the deep abdominal skin furrow that was evident at birth. Discussion: This case represents an unusual antenatal presentation of an amniotic band sequence that escaped prenatal diagnosis with a progressive polyhydramnios as an indirect sign of fetal bowel obstruction caused by an abdominal constricting band. In the presence of chorioamniotic separation and additional ominous ultrasound findings, it is advisable to consider the possibility of an ABS.

A postmortem approach via X-ray computed tomography and thresholding to investigate fracture network evolution in Onagawa shale

<p>A postmortem technique is introduced to investigate the fracture connectivity evolution under elevated confining pressures via a sensitivity analysis. Three Onagawa shale samples are deformed under brittle, ductile, and transition conditions, by increasing the confining pressures. Brittle deformation is characterized by longitudinal splitting of the sample at 3% axial strain, and the onset of transition from brittle to ductile deformation is between 4% ~ 5% axial strain. The ductile deformation is characterized by a distributed conjugate fracture network and strain hardening. In completion of the deformation, the samples are scanned in a commercially available X-ray CT machine. The grayscale values of the primary 2D images were reversed, stacked, and surface rendered to obtain the 3D volume distribution of the fractures. Reversing and surface rendering allowed the acquisition of volume and surface data of the fractures along with their direct visualization. Further, utilizing a residual analysis, the voxel value density distribution that fabricated the fracture network is extracted (Residual histogram). Thresholding of the residual histogram generated volume segments of the final fracture network demonstrating the sensitivity of the fracture network to the choice of threshold. Voxel volumes of fractures alone are obtained by thresholding post-peak voxel values of the residual histogram and consecutive post-peak thresholding shows that the generated volume segments of the fracture network can be utilized to interpret, possible nucleation sites after strain localization, propagation of fractures, and coalescence. Fracture connectivity is quantified by means of relative entropy from information theory, and the relative entropy of size distribution of fracture volumes showed that it is closer to zero with the fractures being well connected. Moreover, the cumulative fracture volume shows a power-law growth towards the failure after a unique threshold to each sample. These results have been validated by previous acoustic emission studies and a 4D tomographic investigation on strain localization of shale. Therefore, despite the postmortem nature of the investigation, the new technique has opened possibilities to investigate the fracture properties and their evolution under elevated confining pressures.</p>

The seasonal evolution of ices on the gullied slopes of Sisyphi Cavi on Mars using CaSSIS and HiRISE orbital images

<p>Gully systems on Mars were first reported by Malin and Edgett (Science, 2000) and because of their similarity to gullies on Earth were attributed to the action of liquid water. They are generally kilometre-scale systems where tributary alcoves lead into channel(s), which terminate in digitate deposits and/or fans. They are found on almost all steep slopes polewards of 30°N/S and are oriented towards the pole in the interval 30-40°, then occur on all slope-orientations >40° (e.g. Conway et al. 2019). Their latitudinal distribution and trends in orientation are strong indicators of a climatic factor playing a pivotal role in their formation. Repeat orbital observations have revealed changes in up to 20% of monitored gully systems (Dundas et al. 2019). When the timing of the changes can be constrained, they occur at the end of the seasonal defrosting period when carbon dioxide ice is present at the surface rendering the temperatures too cold for liquid water to be involved (Dundas et al. 2015, 2019; Pasquon et al., 2016, 2019a,b; Raack et al. 2015, 2020). Some changes involve resolvable quantities of sediment, including motion of metre-scale boulders and erosion of new channels (Dundas et al. 2015; de Haas et al. 2019; Pasquon et al., 2019a).</p><p>Here, we exploit an exceptional time series to monitor the evolution of gullies and the seasonal frost deposits in Sisyphi Cavi (68-74°S, 345°-5°E). We use image data from HiRISE (High Resolution Imaging Science Experiment; 0.25-1 m/pixel), CaSSIS (Colour and Stereo Surface Imaging System; 4.5 m/pixel) and CTX (Context; 6 m/pixel). CaSSIS has four colour filters: BLU, PAN, RED and NIR (centred on 500, 675, 836 and 937 nm respectively); where the BLU filter is particularly useful for picking up surface frosts (Tornabene et al. 2019). We find that gullies and dunes are the last surfaces to defrost in the area. Independent of slope-orientation the alcoves of the gullies defrost first, followed by their channels then their fans. A surprising result considering that intuitively defrosting should progress from the equator-facing alcoves to the equator-facing fans, then from the pole-facing fans to the pole-facing alcoves. We infer that this is a consequence of a) fans and alcoves having contrasting thermal inertia and b) alcoves having slope-facets with a range of local orientations (with some proportion being equator-facing independent of overall orientation).</p><p>We observe dark spots, dark flows and dark fans at the metre-to-ten-metre-scale. These features occur when a continuous solid slab of translucent CO2-ice is penetrated and warmed by sunlight at its base. The sublimation drives gas build-up under the slab, ruptures it, entraining dust and then depositing the dust on the surface (e.g. Kieffer et al. 2006) to form spots, flows and/or fans, depending on the context. We find that the recent activity of gullies promotes the formation of dark spots/flows/fans and are investigating the inverse relationship.</p><p>Acknowledgement: CaSSIS is a project of the University of Bern, with instrument hardware development supported by INAF/Astronomical Observatory of Padova (ASI-INAF agreement n.2020-17-HH.0), and the Space Research Center (CBK) in Warsaw.</p>