Tracking of liver vessel bifurcations in 3D+t ultrasound by subsequent approximations of a rigid shape model

2018 ◽  
Author(s):  
Heinrich Martin Overhoff
Keyword(s):  
Shape Model ◽  
Vessel Bifurcations

Human face shape classification method based on active shape model

2009 ◽  
Vol 29 (10) ◽  
pp. 2710-2712 ◽  
Author(s):  
Li-qiang DU ◽  
Peng JIA ◽  
Zong-tan ZHOU ◽  
De-wen HU
Keyword(s):  
Classification Method ◽  
Active Shape Model ◽  
Shape Classification ◽  
Human Face ◽  
Shape Model ◽  
Face Shape ◽  
Active Shape

scholarly journals Semiautomatic Segmentation of Vertebrae in Lateral X-rays Using a Conditional Shape Model

2007 ◽  
Vol 14 (10) ◽  
pp. 1156-1165 ◽  
Author(s):  
J. Eugenio Iglesias ◽  
Marleen de Bruijne
Keyword(s):  
X Rays ◽  
Shape Model ◽  
Semiautomatic Segmentation

scholarly journals Geometric correction for thermographic images of asteroid 162173 Ryugu by TIR (thermal infrared imager) onboard Hayabusa2

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Takehiko Arai ◽  
Tatsuaki Okada ◽  
Satoshi Tanaka ◽  
Tetsuya Fukuhara ◽  
Hirohide Demura ◽  
...  
Keyword(s):  
Surface Roughness ◽  
High Surface ◽  
Thermal Inertia ◽  
Thermal Infrared ◽  
Shape Model ◽  
Infrared Imager ◽  
Least Squares Fit ◽  
Temperature Maps ◽  
Pixel Scale ◽  
Thermal Infrared Imager

AbstractThe thermal infrared imager (TIR) onboard the Hayabusa2 spacecraft performed thermographic observations of the asteroid 162173 Ryugu (1999 JU$$_3$$ 3 ) from June 2018 to November 2019. Our previous reports revealed that the surface of Ryugu was globally filled with porous materials and had high surface roughness. These results were derived from making the observed temperature maps of TIR using a projection method onto the shape model of Ryugu as geometric corrections. The pointing directions of TIR were calculated using an interpolation of data from the SPICE kernels (NASA/NAIF) during the periods when the optical navigation camera (ONC) and the light detection and ranging (LIDAR) observations were performed. However, the mapping accuracy of the observed TIR images was degraded when the ONC and LIDAR were not performed with TIR. Also, the orbital and attitudinal fluctuations of Hayabusa2 increased the error of the temperature maps. In this paper, to solve the temperature image mapping problems, we improved the correction method by fitting all of the observed TIR images with the surface coordinate addressed on the high-definition shape model of Ryugu (SFM 800k v20180804). This correction adjusted the pointing direction of TIR by rotating the TIR frame relative to the Hayabusa2 frame using a least squares fit. As a result, the temperature maps spatially spreading areas were converged within high-resolved $$0.5^\circ$$ 0 . 5 ∘ by $$0.5^\circ$$ 0 . 5 ∘ maps. The estimated thermal inertia, for instance, was approximately 300$$\sim$$ ∼ 350 Jm$$^{-2}$$ - 2 s$$^{-0.5}$$ - 0.5 K$$^{-1}$$ - 1 at the hot area of the Ejima Saxum. This estimation was succeeded in case that the surface topographic features were larger than the pixel scale of TIR. However, the thermal inertia estimation of smooth terrains, such as the Urashima crater, was difficult because of surface roughness effects, where roughness was probably much smaller than the pixel scale of TIR.

Echocardiogram segmentation using active shape model and mean squared eigenvalue error

2021 ◽  
Vol 69 ◽  
pp. 102807
Author(s):  
Yasser Ali ◽  
Soosan Beheshti ◽  
Farrokh Janabi-Sharifi
Keyword(s):  
Active Shape Model ◽  
Shape Model ◽  
Active Shape

scholarly journals Detection of vessel bifurcations in CT scans for automatic objective assessment of deformable image registration accuracy

2021 ◽  
Author(s):  
Guillaume Cazoulat ◽  
Brian M Anderson ◽  
Molly M McCulloch ◽  
Bastien Rigaud ◽  
Eugene J Koay ◽  
...  
Keyword(s):  
Image Registration ◽  
Objective Assessment ◽  
Deformable Image Registration ◽  
Ct Scans ◽  
Registration Accuracy ◽  
Vessel Bifurcations

scholarly journals Practical application of synthetic head models in real ballistic cases

2021 ◽  
Author(s):  
F. Riva ◽  
T. Fracasso ◽  
A. Guerra ◽  
P. Genet
Keyword(s):  
Soft Tissues ◽  
Spherical Model ◽  
Brain Parenchyma ◽  
Human Bone ◽  
Shape Model ◽  
The Difference ◽  
Open Shape ◽  
The Brain ◽  
Synthetic Models ◽  
Representative Material

AbstractIn shooting crimes, ballistics tests are often recommended in order to reproduce the wound characteristics of the involved persons. For this purpose, several “simulants” can be used. However, despite the efforts in the research of “surrogates” in the field of forensic ballistic, the development of synthetic models needs still to be improved through a validation process based on specific real caseworks. This study has been triggered by the findings observed during the autopsy performed on two victims killed in the same shooting incident, with similar wounding characteristics; namely two retained head shots with ricochet against the interior wall of the skull; both projectiles have been recovered during the autopsies after migration in the brain parenchyma. The thickness of the different tissues and structures along the bullets trajectories as well as the incident angles between the bullets paths and the skull walls have been measured and reproduced during the assemblage of the synthetic head models. Two different types of models (“open shape” and “spherical”) have been assembled using leather, polyurethane and gelatine to simulate respectively skin, bone and soft tissues. Six shots have been performed in total. The results of the models have been compared to the findings of post-mortem computed tomography (PMCT) and the autopsy findings.Out of the six shots, two perforated the models and four were retained. When the projectile was retained, the use of both models allowed reproducing the wounds characteristics observed on both victims in terms of penetration and ricochet behaviour. However, the projectiles recovered from the models showed less deformation than the bullets collected during the autopsies. The “open shape” model allowed a better controlling on the shooting parameters than the “spherical” model. Finally, the difference in bullet deformation could be caused by the choice of the bone simulant, which might under-represent either the strength or the density of the human bone. In our opinion, it would be worth to develop a new, more representative material for ballistic which simulates the human bone.

scholarly journals Robust and Accurate Mandible Segmentation on Dental CBCT Scans Affected by Metal Artifacts Using a Prior Shape Model

2021 ◽  
Vol 11 (5) ◽  
pp. 364
Author(s):  
Bingjiang Qiu ◽  
Hylke van der van der Wel ◽  
Joep Kraeima ◽  
Haye Hendrik Glas ◽  
Jiapan Guo ◽  
...  
Keyword(s):  
State Of The Art ◽  
Maxillofacial Surgery ◽  
Cone Beam ◽  
Oral And Maxillofacial Surgery ◽  
Metal Artifacts ◽  
Shape Model ◽  
High Attenuation ◽  
Mandible Shape ◽  
Prior Shape ◽  
Segmentation Models

Accurate mandible segmentation is significant in the field of maxillofacial surgery to guide clinical diagnosis and treatment and develop appropriate surgical plans. In particular, cone-beam computed tomography (CBCT) images with metal parts, such as those used in oral and maxillofacial surgery (OMFS), often have susceptibilities when metal artifacts are present such as weak and blurred boundaries caused by a high-attenuation material and a low radiation dose in image acquisition. To overcome this problem, this paper proposes a novel deep learning-based approach (SASeg) for automated mandible segmentation that perceives overall mandible anatomical knowledge. SASeg utilizes a prior shape feature extractor (PSFE) module based on a mean mandible shape, and recurrent connections maintain the continuity structure of the mandible. The effectiveness of the proposed network is substantiated on a dental CBCT dataset from orthodontic treatment containing 59 patients. The experiments show that the proposed SASeg can be easily used to improve the prediction accuracy in a dental CBCT dataset corrupted by metal artifacts. In addition, the experimental results on the PDDCA dataset demonstrate that, compared with the state-of-the-art mandible segmentation models, our proposed SASeg can achieve better segmentation performance.

scholarly journals Pressure effects on water vapour lines: beyond the Voigt profile

2012 ◽  
Vol 370 (1968) ◽  
pp. 2495-2508 ◽  
Author(s):  
N. H. Ngo ◽  
H. Tran ◽  
R. R. Gamache ◽  
J. M. Hartmann
Keyword(s):  
Water Vapour ◽  
Line Shape ◽  
Pressure Effects ◽  
Shape Model ◽  
Line Shapes ◽  
Voigt Profile ◽  
Voigt Model ◽  
Velocity Changes ◽  
Dynamics Simulations ◽  
Induced Velocity

A short overview of recent results on the effects of pressure (collisions) regarding the shape of isolated infrared lines of water vapour is presented. The first part of this study considers the basic collisional quantities, which are the pressure-broadening and -shifting coefficients, central parameters of the Lorentzian (and Voigt) profile and thus of any sophisticated line-shape model. Through comparisons of measured values with semi-classical calculations, the influences of the molecular states (both rotational and vibrational) involved and of the temperature are analysed. This shows the relatively unusual behaviour of H 2 O broadening, with evidence of a significant vibrational dependence and the fact that the broadening coefficient (in cm −1 atm −1 ) of some lines increases with temperature. In the second part of this study, line shapes beyond the Voigt model are considered, thus now taking ‘velocity effects’ into account. These include both the influence of collisionally induced velocity changes that lead to the so-called Dicke narrowing and the influence of the dependence of collisional parameters on the speed of the radiating molecule. Experimental evidence of deviations from the Voigt shape is presented and analysed. The interest of classical molecular dynamics simulations, to model velocity changes, together with semi-classical calculations of the speed-dependent collisional parameters for line-shape predictions from ‘first principles’, are discussed.

Sign in / Sign up

Export Citation Format

Share Document