Medical inter-modality volume-to-volume translation Chen, Jinjin; Huai, Yongjian; Ma, Ji
Journal of King Saud University. Computer and information sciences,
December 2023, 2023-12-00, 2023-12-01, Letnik:
35, Številka:
10
Journal Article
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Many clinical works require medical inter-modality imaging results since the supplementary imaging information from different modalities can be combined to provide better decision-making. ...Traditionally, this is done by scanning patients with different modalities, which is expensive, time-consuming, laborious, and may have health risks. Motivated by this problem, we propose a GAN-based method called W-VCT2VMRIGAN, which can automatically synthesize volumetric MRI from volumetric CT despite the presence of approximately %6 of imperfectly-paired slices, and thus can reduce cost, time, labor, and health risks caused by the traditional method. To show its effectiveness, we applied brain and pelvis datasets from clinical works to it. We also qualitatively and quantitatively compared it with the state-of-the-art techniques. The experimental result shows that in reference to the ground truth, our method outperforms the state-of-the-art Pix2Pix (12%, 15%, 260% better in average SSIM, average MS-SSIM3, MOS for brain; 12%, 9%, 230% better in average SSIM, average MS-SSIM3, MOS for pelvis), CycleGAN (30%, 24%, 520% better in average SSIM, average MS-SSIM3, MOS for brain; 42%, 56%, 680% better in average SSIM, average MS-SSIM3, MOS for pelvis), and MedSynthesisV1 (2%, 1%, 380% better in average SSIM, average MS-SSIM3, MOS for brain; 10%, 9%, 150% better in average SSIM, average MS-SSIM3, MOS for pelvis) techniques. Furthermore, we performed an ablation study for our method. The experimental result shows that in comparison to other variants, our method is optimal. Finally, we performed an experiment to choose the optimal hyperparameter regarding the number of epochs. The experimental result shows that the optimal number of epochs for brain and pelvis datasets are 900 and 400, respectively.
► A simple route to prepare the Li4Ti5O12/C by one-step solid-state reaction. ► Carbon source and carbon content are two important factors on the electrochemical performances of Li4Ti5O12/C. ► ...As-prepared Li4Ti5O12/C under optimized conditions shows excellent electrochemical performances.
Li4Ti5O12/C composites were synthesized by one-step solid-state reaction method using four commonly used organic compounds or organic polymers as carbon source, i.e., polyacrylate acid (PAA), citric acid (CA), maleic acid (MA) and polyvinyl alcohol (PVA). The physical characteristics of Li4Ti5O12/C composites were investigated by X-ray diffraction, electron microscopy, Raman spectroscopy, particle size distribution and thermogravimetry-derivative thermogravimetry techniques. Their electrochemical properties were characterized by cyclic voltammograms, electrochemical impedance spectra, constant current charge–discharge and rate charge–discharge. These analyses indicated that the carbon source and carbon content have a great effect on the physical and electrochemical performances of Li4Ti5O12/C composites. An ideal carbon source and appropriate carbon content effectively improved the electrical contact between the Li4Ti5O12 particles, which enhanced the discharge capacity and rate capability of Li4Ti5O12/C composites. PAA was the best carbon source for the synthesis of Li4Ti5O12/C composites. When the carbon content was 3.49wt.% (LiOH·H2O/PAA molar ratio of 1), as-prepared Li4Ti5O12/C showed the maximum discharge capacity. At 0.2C, initial capacity of the optimized sample was 168.6mAhg−1 with capacity loss of 2.8% after 50 cycles. At 8 and 10C, it showed discharge capacities of 143.5 and 132.7mAhg−1, with capacity loss of 8.7 and 9.9% after 50 cycles, respectively.
There are three main types of forest fires: surface fires, tree crown fires, and underground fires. The frequency of surface fires and tree crown fires accounts for more than 90% of the overall ...frequency of forest fires. In order to construct an immersive three-dimensional visualization simulation of forest fires, various forest fire ignition methods, forest fire spread, and fire extinguishing simulation exercises are studied. This paper proposes a lightweight forest fire spread method based on cellular automata applied to the virtual 3D world. By building a plant model library using cells to express different plants, and by building a 3D geometric model of plants to truly capture the combustion process of a single plant, we can further simulate forest-scale fire propagation and analyze the factors that affect forest fire spread. In addition, based on the constructed immersive forest scene, this study explored various forms of fire extinguishing methods in the virtual environment, mainly liquid flame retardants such as water guns, helicopter-dropped flame retardants, or simulated rainfall. Therefore, the forest fire occurrence, spread, and fire extinguishing process can be visualized after the interactive simulation is designed and implemented. Finally, this study greatly enhanced the immersion and realism of the 3D forest fire scene by simulating the changes in plant materials during the spread of a forest fire.
Computer vision technology has promoted the rapid development of forest observation equipment, and video photography (videogrammetry) has provided new ideas and means for forestry investigation. ...According to the characteristics of videogrammetry, a spiral observation method is proposed. Meanwhile, a new point cloud data processing method is proposed, which extracts a point cloud at the diameter at breast height (DBH) section and determines the DBH of trees through cylinder fitting and circle fitting, according to the characteristics of the point cloud model and the real situation of occlusion in the sampled area, and then calculates the biomass. Through a large number of experiments, a more effective and relatively high-precision method for DBH extraction is obtained. Compared with the field survey data, the bias% of DBH extracted by videogrammetry was −3.19~2.87%, and the RMSE% was 5.52~7.76%. Compared with the TLS data, the bias% of −4.78~2.38%, and the RMSE% was 5.63~9.87%. The above-ground biomass (AGB) estimates from the videogrammetry showed strong agreement with the reference values with concordance correlation coefficient (CCC) and the RMSE values of 0.97 and 19.8 kg. Meanwhile, the AGB estimate from TLS agrees with the CCC values and the RMSE of 0.97 and 17.23 kg. Videogrammetry is not only cheap, low cost, and fast, but also can be observed in a relatively complex forest environment, with strong anti-interference ability. The experimental results prove that its accuracy is comparable to TLS and photogrammetry. Thus this work is quite valuable in a forest resources survey. We believe that the calculation accuracy of our new method can fully meet the needs of the forest survey.
•Propose an immersive method of sketch-based tree modeling in virtual reality.•Present a series of algorithms to deal with the problems of generating branch geometry for real-time 3D ...sketching.•Provide a bidirectional ray-hit algorithm to determine the branch radius in real-time.•Present a twigs generation algorithm to randomly generate twigs based on Perlin noise and parent branch direction.
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Tree modeling has been a widely-discussed topic in computer graphics. However, with existing methods, the modeling process is occupied with complex data collection and tedious parameter adjustment, lacking a rich sensory modeling experience. In this paper, we propose an approach to sketch-based tree modeling in an immersive virtual reality environment, aiming to lower the difficulty of modeling and enhance the immersion in the designing process. We first present a sketch sampling and points optimization algorithm to obtain the skeleton of the branch in 3D space. As generating geometry along the skeleton, we apply a vector-projection method to fix the branch polygon twisting. Then, we introduce a bidirectional ray-hit algorithm to determine the branch radius as real-time sketching. To generate random twigs on branches, we introduce a twigs generation algorithm based on Perlin noise and the parent branch direction. Finally, we design a series of interactive methods for users to create tree models in a 3D virtual scene with the VR HMD and controller. Experimental results indicate that our approach can accomplish creating realistic tree models in real-time. The interactive and immersive modeling experience enables users to readily convey their ideas on tree structures in a simple and direct way of sketching. Visualizing and modifying the real-time generated branch results can contribute to provoking the inspiration for creation.
Combustibles, topography, and weather factors are the three essential factors affecting forest fire behavior, and current forest fire spread models need to consider weather factors fully. This paper ...proposes a forest fire spread method based on environmental weather factors to present a visualized simulation of forest fire spread in the natural environment. Forest pyrolysis differs based on water content, so a single-tree pyrolysis model with temperature as its core has been constructed to describe the differences in forest pyrolysis during different seasons visually. In addition, based on the improved Huygens principle as the theoretical basis for forest fire spread, weather factors such as wind speed, wind direction, and precipitation controlled by weather are coupled with the forest fire spread process. And the forest fire spread in three-dimensional scenarios is simulated by considering environmental factors. The visualization of the forest fire extinguishing process caused by precipitation is realized. Finally, the interaction between rain and snow, terrain and trees is realized when precipitation affects the corresponding landscape and vegetation texture to enhance the realism of the constructed forest environment. In short, this paper proposes a forest fire spread method based on environmental weather factors, which intuitively expresses the influence of different weather factors on forest fire spread, thereby improving the immersive experience of the related senses and realizing realistic scene roaming.
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•Based on the single tree pyrolysis model, differentiating forest burning.•Visualization of the influence of simulated weather factors on forest fire behavior.•Use texture mixing technology to construct 3D forest weather scene.
State-of-the-art approaches to forest fire spread are based on either 2D numerical simulations of trees on GIS or rough 3D visualization. In this paper, we approximate the tree form by dynamically ...changing sets of tree-shape modules according to the morphological structure and wind fields. Guided by finite state machine, we define the states of equilibrium, heating, pyrolysis, cooling and destruction of tree-shape modules. Interactions between tree-shape modules drive the state transfer to achieve forest fire spread. Additionally, Loose Quadtrees are adopted to the spatial distribution of trees, which allows us to maintain the visual fidelity of the representation while rendering the forest fire spreads in real-time. Our method allows us to construct the Jiufeng forest example about 10km x 10km extent at interactive rates. The capabilities of tree-shape modules and forest fire spread visualization are demonstrated by numerous examples.
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•Use FSM to define the state and transition rules of the tree-shape module, and adopt the state to drive the temperature, moisture, and mass of the tree to simulate the pyrolysis.•Use Loose Quadtree to generate tree-shape modules in real time, and tree-shape modules can be deformed by the joint action of wind field and terrain slope to control the spread of forest fire.•Calculate the barycentric coordinates of a triangle in a tree surface mesh as the position of preset flame and store in the Priority Queue to orderly generate flames on trees.
We reported proton-conducting membranes with novel microstructure based on partially phosphorylated poly(vinyl alcohol) (P-PVA) and polyethylene glycol (PEG) grafted silica (PEG-SiO
2
) particles. ...The PEG-SiO
2
particles were synthesized through acid catalyzed hydrolysis and condensation reactions. The membranes were characterized for their mechanical, structural, morphological, and electrical properties by employing tensile test, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), impedance analyzer, respectively. In these membranes, P-PVA acts as the proton source and PEG act as the proton solvent. The PEG-riched phases in the hybrid membrane form continuous ionic conducting pathways and subsequently give high ionic conductivity. The results suggest that the obtained membrane shows good thermal stability, excellent mechanical property and high ionic conductivity, and the low-cost hybrid membrane can be a promising candidate for intermediate temperature fuel cell systems.
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