scholarly journals Performance evaluation of a newly developed three-dimensional model-based global-to-local registration in prostate cancer

2019 ◽  
Vol 60 (5) ◽  
pp. 595-602 ◽  
Author(s):  
Mitsuhiro Nakamura ◽  
Megumi Nakao ◽  
Hideaki Hirashima ◽  
Hiraku Iramina ◽  
Takashi Mizowaki
Keyword(s):  
Prostate Cancer ◽  
Hausdorff Distance ◽  
3D Model ◽  
Three Dimensional ◽  
Computation Time ◽  
Surface Registration ◽  
Registration Accuracy ◽  
Model Based ◽  
Global Registration ◽  
Significant Difference

Abstract We evaluated the performance of a newly developed three-dimensional (3D) model-based global-to-local registration of multiple organs, by comparing it with a 3D model-based global registration in the prostate region. This study included 220 prostate cancer patients who underwent intensity-modulated radiotherapy or volumetric-modulated arc therapy. Our registration proceeded sequentially, i.e. global registration including affine and piece-wise affine transformation followed by local registration. As a local registration, Laplacian-based and finite element method-based registration was implemented in Algorithm A and B, respectively. Algorithm C was for global registration alone. The template models for the prostate, seminal vesicles, rectum and bladder were constructed from the first 20 patients, and then three different registrations were performed on these organs for the remaining 200 patients, to assess registration accuracy. The 75th percentile Hausdorff distance was <1 mm in Algorithm A; it was >1 mm in Algorithm B, except for the prostate; and 3.9 mm for the prostate and >7.8 mm for other organs in Algorithm C. The median computation time to complete registration was <101, 30 and 16 s in Algorithms A, B and C, respectively. Analysis of variance revealed significant differences among Algorithms A–C in the Hausdorff distance and computation time. In addition, no significant difference was observed in the difference of Hausdorff distance between Algorithm A and B with Tukey’s multiple comparison test. The 3D model-based global-to-local registration, especially that implementing Laplacian-based registration, completed surface registration rapidly and provided sufficient registration accuracy in the prostate region.

scholarly journals Comparison of Accuracies between Real-Time Nonrigid and Rigid Registration in the MRI–US Fusion Biopsy of the Prostate

Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1481
Author(s):  
Sung Il Hwang ◽  
Hyungwoo Ahn ◽  
Hak Jong Lee ◽  
Sung Kyu Hong ◽  
Seok-Soo Byun ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Real Time ◽  
Prostate Volume ◽  
Volume Measurement ◽  
Nonrigid Registration ◽  
Targeted Biopsy ◽  
Registration Accuracy ◽  
Detection Rates ◽  
Rigid Registration ◽  
Significant Difference

Magnetic resonance imaging (MRI) is increasingly important in the detection and localization of prostate cancer. Regarding suspicious lesions on MRI, a targeted biopsy using MRI fused with ultrasound (US) is widely used. To achieve a successful targeted biopsy, a precise registration between MRI and US is essential. The purpose of our study was to show any decrease in errors using a real-time nonrigid registration technique for prostate biopsy. Nineteen patients with suspected prostate cancer were prospectively enrolled in this study. Registration accuracy was calculated by the measuring distance of corresponding points by rigid and nonrigid registration between MRI and US, and compared for rigid and nonrigid registration methods. Overall cancer detection rates were also evaluated by patient and by core. Prostate volume was measured automatically from MRI and manually from US, and compared to each other. Mean distances between the corresponding points in MRI and US were 5.32 ± 2.61 mm for rigid registration and 2.11 ± 1.37 mm for nonrigid registration (p < 0.05). Cancer was diagnosed in 11 of 19 patients (57.9%), and in 67 of 266 biopsy cores (25.2%). There was no significant difference in prostate-volume measurement between the automatic and manual methods (p = 0.89). In conclusion, nonrigid registration reduces targeting errors.

Bas-relief Modeling from RGB Monocular Images with Regional Division Characteristics

2021 ◽  
Author(s):  
Xinli Wu ◽  
Jiali Luo ◽  
Minxiong Zhang ◽  
Wenzhen Yang
Keyword(s):  
3D Model ◽  
Three Dimensional ◽  
Depth Information ◽  
Model Based ◽  
Region Division ◽  
Calibration Algorithm ◽  
Image Area ◽  
Monocular Image ◽  
Relationship Of ◽  
Image Depth

Abstract Bas-relief, a form of sculpture art representation, has the general characteristics of sculpture art and satisfies people’s visual and tactile feelings by fully leveraging the advantages of painting art in composition, subject matter, and spatial processing. Bas-relief modeling using images is generally classified into the method based on the three-dimensional (3D) model, that based on the image depth restoration, and that based on multi-images. The 3D model method requires the 3D model of the object in advance. Bas-relief modeling based on the image depth restoration method usually either uses a depth camera to obtain object depth information or restores the depth information of pixels through the image. Bas-relief modeling based on the multi-image requires a short running time and has high efficiency in processing high resolution level images. Our method can automatically obtain the pixel height of each area in the image and can adjust the concave–convex relationship of each image area to obtain a bas-relief model based on the RGB monocular image. First, the edge contour of an RGB monocular image is extracted and refined by the Gauss difference algorithm based on tangential flow. Subsequently, the complete image contour information is extracted and the region-based image segmentation is used to calibrate the region. This method has improved running speed and stability compared with the traditional algorithm. Second, the regions of the RGB monocular image are divided by the improved connected-component labeling algorithm. In the traditional region calibration algorithm, the contour search strategy and the inner and outer contour definition rules of the image considered result in a low region division efficiency. This study uses an improved contour-based calibration algorithm. Then, the 3D pixel point cloud of each region is calculated by the shape-from-shading algorithm. The concave–convex relationships among these regions can be adjusted by human–computer interaction to form a reasonable bas-relief model. Lastly, the bas-relief model is obtained through triangular reconstruction using the Delaunay triangulation algorithm. The final bas-relief modeling effect is displayed by OpenGL. In this study, six groups of images are selected for conducting regional division tests, and the results obtained by the proposed method and other existing methods are compared. The proposed algorithm shows improved image processing running time for different complexity levels compared with the traditional two-pass scanning method and seed filling method (by approximately 2 s) and with the contour tracking method (by approximately 4 s). Next, image depth recovery experiments are conducted on four sets of images, namely the “ treasure seal,” “Wen Emperor seal,” “lily pattern,” and “peacock pattern,” and the results are compared. The depth of the image obtained by the traditional algorithm is generally lower than the actual plane, and the relative height of each region is not consistent with the actual situation. The proposed algorithm provides height values consistent with the height value information judged in the original image and adjusts the accurate concave–convex relationships. Moreover, the noise in the image is reduced and relatively smooth surfaces are obtained, with accurate concave–convex relationships. The proposed bas-relief model based on RGB monocular images can automatically determine the pixel height of each image area in the image and adjust the concave–convex relationship of each image area. In addition, it can recover the 3D model of the object from the image, enrich the object of bas-relief modeling, and expand the creation space of bas-relief, thereby improving the production efficiency of the bas-relief model based on RGB monocular images. The method has certain shortcomings, which require further exploration. For example, during the process of image contour extraction for region division, small differences exist between the obtained result and the actual situation, which can in turn affect the image depth recovery in the later stage. In addition, partial distortion may occur in the process of 3D reconstruction, which requires further research on point cloud data processing to reconstruct a high-quality three-dimensional surface.

scholarly journals A comparison of a two-dimensional depth averaged flow model and a three-dimensional RANS model for predicting tsunami inundation and fluid forces

2018 ◽  
Author(s):  
Xinsheng Qin ◽  
Michael Motley ◽  
Randall LeVeque ◽  
Frank Gonzalez ◽  
Kaspar Mueller
Keyword(s):  
Built Environment ◽  
3D Model ◽  
Computational Cost ◽  
Three Dimensional ◽  
Vertical Direction ◽  
3D Models ◽  
Tsunami Inundation ◽  
Model Based ◽  
Fine Mesh ◽  
2D Model

Abstract. The numerical modeling of tsunami inundation that incorporates the built environment of coastal communities is challenging for both depth-integrated 2D and 3D models, not only in modeling the flow, but also in predicting forces on coastal structures. For depth-integrated 2D models, inundation and flooding in this region can be very complex with variation in the vertical direction caused by wave breaking on shore and interactions with the built environment and the model may not be able to produce enough detail. For 3D models, a very fine mesh is required to properly capture the physics, dramatically increasing the computational cost and rendering impractical the modeling of some problems. In this paper, comparisons are made between GeoClaw, a depth-integrated 2D model based on the nonlinear shallow water equations (NSWE), and OpenFOAM, a 3D model based on Reynolds Averaged Navier-Stokes (RANS) equation for tsunami inundation modeling. The two models were first validated against existing experimental data of a bore impinging onto a single square column. Then they were used to simulate tsunami inundation of a physical model of Seaside, Oregon. The resulting flow parameters from the models are compared and discussed, and these results are used to extrapolate tsunami-induced force predictions. It was found that the 2D model did not accurately capture the important details of the flow near initial impact due to the transiency and large vertical variation of the flow. Tuning the drag coefficient of the 2D model worked well to predict tsunami forces on structures in simple cases but this approach was not always reliable in complicated cases. The 3D model was able to capture transient characteristic of the flow, but at a much higher computational cost; it was found this cost can be alleviated by subdividing the region into reasonably sized subdomains without loss of accuracy in critical regions.

Computer Three-Dimensional Positioning and Reconstruction of Continuous Slice Images of Biological Tissues

2020 ◽  
Vol 10 (2) ◽  
pp. 469-476
Author(s):  
Ying He
Keyword(s):  
3D Model ◽  
Morphological Changes ◽  
Three Dimensional ◽  
Biological Tissues ◽  
Computer Processing ◽  
Pathological Changes ◽  
Registration Accuracy ◽  
Tissue Slices ◽  
Registration Algorithm ◽  
Image Registration Algorithm

The physiological and pathological changes of organisms will have certain effects on the morphology of tissues and organs. Conversely, the morphological changes of tissues and organs can also reflect the physiological and pathological changes of organisms to some extent. The bio-tissue slice can provide people with two-dimensional information of the tissue structure on a certain section. In this paper, the image registration algorithm based on mutual information is used to register the slice images of different tissues, and then the image segmentation is used to improve the registration accuracy. The three-dimensional data of the organizational structure is obtained, and the three-dimensional image of the tissue is reconstructed by computer processing. The reconstruction of different tissue slices is used to prove that the algorithm is fast and accurate, and the reconstruction speed of the 3D model is improved, which is of great significance for shortening the diagnostic waiting time.

Knee Bone Surface Registration Using the Lipschitz Optimization Algorithm

2012 ◽  
Vol 443-444 ◽  
pp. 537-541
Author(s):  
Xiao Peng Wang ◽  
Yuan Zhi Cheng ◽  
Ming Ming Zhao ◽  
Xiao Hua Ding ◽  
Jing Bai
Keyword(s):  
Search Algorithm ◽  
Three Dimensional ◽  
Image Data ◽  
Surface Registration ◽  
Data Sets ◽  
Bone Surface ◽  
Registration Accuracy ◽  
Mr Image ◽  
Lipschitz Optimization ◽  
Animal Data

We describe a technique for the registration of three dimensional (3D) knee bone surface points from MR image data sets. This technique is grounded on a mathematical theory – Lipschitz optimization. Based on this theory, we propose a global search algorithm that simultaneously determines the transformation and point correspondences. Compared with the other three registration approaches (ICP, EM-ICP, and genetic algorithms), the new proposed method achieved the highest registration accuracy on animal data.

scholarly journals Reconstruction of Three-Dimensional Tibiofemoral Kinematics Using Single-Plane Fluoroscopy and a Personalized Kinematic Model

2021 ◽  
Vol 11 (20) ◽  
pp. 9415
Author(s):  
Cheng-Chung Lin ◽  
Hsuan-Lun Lu ◽  
Tung-Wu Lu ◽  
Chia-Yang Wang ◽  
Jia-Da Li ◽  
...  
Keyword(s):  
Image Registration ◽  
Knee Joint ◽  
Imaging System ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Plane Motion ◽  
Registration Accuracy ◽  
Single Plane ◽  
Model Based ◽  
Tibiofemoral Kinematics

Model-based 3D/2D image registration using single-plane fluoroscopy is a common setup to determine knee joint kinematics, owing to its markerless aspect. However, the approach was subjected to lower accuracies in the determination of out-of-plane motion components. Introducing additional kinematic constraints with an appropriate anatomical representation may help ameliorate the reduced accuracy of single-plane image registration. Therefore, this study aimed to develop and evaluate a multibody model-based tracking (MbMBT) scheme, embedding a personalized kinematic model of the tibiofemoral joint for the measurement of tibiofemoral kinematics. The kinematic model was consisted of three ligaments and an articular contact mechanism. The knee joint activities in six volunteers during isolated knee flexion, lunging, and sit-to-stand motions were recorded with a biplane X-ray imaging system. The tibiofemoral kinematics determined with the MbMBT and mediolateral view fluoroscopic images were compared against those determined using biplane fluoroscopic images. The MbMBT was demonstrated to yield tibiofemoral kinematics with precision values in the range from 0.1 mm to 1.1 mm for translations and from 0.2° to 1.3° for rotations. The constraints provided by the kinematic model were shown to effectively amend the nonphysiological tibiofemoral motion and not compromise the image registration accuracy with the proposed MbMBT scheme.

scholarly journals Optimal Design of a BLDC Motor Considering Three-Dimensional Structures Using the Response Surface Methodology

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 461
Author(s):  
Seong-Tae Jo ◽  
Hyo-Seob Shin ◽  
Young-Geun Lee ◽  
Ji-Hun Lee ◽  
Jang-Young Choi
Keyword(s):  
Response Surface Methodology ◽  
Optimal Design ◽  
Response Surface ◽  
3D Model ◽  
3D Structure ◽  
Three Dimensional ◽  
Computation Time ◽  
Design Time ◽  
3D Finite Element Method ◽  
Method Analysis

In this paper, the optimal design of a brushless direct current motor with a three-dimensional (3D) structure using the response surface methodology (RSM) is presented. There were two optimization goals: reduction of the cogging torque and maintenance of the back electromotive force to prevent performance degradation. For motors with a 3D structure, a 3D finite element method analysis is essential, though it requires considerable computation time. Therefore, to reduce the optimal design time, the 3D structure was placed on the 2D plane. Thereafter, a 2D corrected model was applied to the RSM. For the validity of the technique, the analysis results of the initial 3D model, 2D model, and 2D corrected model were compared, and the results of the optimal design 3D model, 2D corrected model, and experiment were compared.

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