3D-PMRNN: Reconstructing three-dimensional porous media from the two-dimensional image with recurrent neural network

Author(s):  
Fan Zhang ◽  
Xiaohai He ◽  
Qizhi Teng ◽  
Xiaohong Wu ◽  
Xiucheng Dong
Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 929
Author(s):  
Xudong Yang ◽  
Zexiao Li ◽  
Linlin Zhu ◽  
Yuchu Dong ◽  
Lei Liu ◽  
...  

Taper-cutting experiments are important means of exploring the nano-cutting mechanisms of hard and brittle materials. Under current cutting conditions, the brittle-ductile transition depth (BDTD) of a material can be obtained through a taper-cutting experiment. However, taper-cutting experiments mostly rely on ultra-precision machining tools, which have a low efficiency and high cost, and it is thus difficult to realize in situ measurements. For taper-cut surfaces, three-dimensional microscopy and two-dimensional image calculation methods are generally used to obtain the BDTDs of materials, which have a great degree of subjectivity, leading to low accuracy. In this paper, an integrated system-processing platform is designed and established in order to realize the processing, measurement, and evaluation of taper-cutting experiments on hard and brittle materials. A spectral confocal sensor is introduced to assist in the assembly and adjustment of the workpiece. This system can directly perform taper-cutting experiments rather than using ultra-precision machining tools, and a small white light interference sensor is integrated for in situ measurement of the three-dimensional topography of the cutting surface. A method for the calculation of BDTD is proposed in order to accurately obtain the BDTDs of materials based on three-dimensional data that are supplemented by two-dimensional images. The results show that the cutting effects of the integrated platform on taper cutting have a strong agreement with the effects of ultra-precision machining tools, thus proving the stability and reliability of the integrated platform. The two-dimensional image measurement results show that the proposed measurement method is accurate and feasible. Finally, microstructure arrays were fabricated on the integrated platform as a typical case of a high-precision application.


2004 ◽  
Vol 16 (05) ◽  
pp. 238-243
Author(s):  
WEI-MIN JENG ◽  
MING-CHUNG CHIANG

Positron emission tomography (PET) images can be used to judge whether or not a person's bodily tissue is showing abnormal metabolism, providing a tool for early diagnosis and treatment of illnesses. Contemporary PET scanners have retracted their septa in order to increase the collected coincidental events. Thus, the protocol either needs to undergo three-dimensional image reconstruction, or use rebinning formulas to perform the less expensive two-dimensional image reconstruction for final images. Reconstruction using the second method saves image reconstruction time. The main goal of the paper is to further improve the performance by overlapping the rebinning and two-dimensional reconstruction operations, so as to early start in reconstruction, and to be able to undergo image reconstruction based on the pipelined direct sinograms. Frequency distance relations are analyzed in detail to generate the Fourier transformed sinograms in order for subsequent pipelined stages of reconstruction. The two-dimensional reconstruction operation does not have to wait until the completion of all sinogram generations, therefore it can hide most of the time spent in rebinning operations. The associated parameters can be pre-calculated indiscriminately beforehand for best performance.


1988 ◽  
Vol 98 (1) ◽  
pp. 48-52 ◽  
Author(s):  
Lawrence J. Marentette ◽  
Robert H. Maisel

Correct preoperative planning is an essential aspect of any surgical procedure and it is equally important when midfacial reconstruction is contemplated. Conventional methods include standard radiographic views, plain tomography, photography, and computerized tomography. All of these methods produce a two-dimensional image of the patient. Three-dimensional computerized tomographic reconstruction allows the surgeon to visualize the entire facial skeletal deformity. The three-dimensional image produced also allows comparison of the deformity to surrounding normal structures, and thus makes the correction of facial asymmetries more precise. This new modality is particularly useful in the preoperative planning for patients with zygomaticomaxillary defects that result from either trauma or maxillectomy. Illustrative examples of patients in whom autogenous bone graft zygomaticomaxillary reconstruction was performed, after trauma and subsequent to subtotal maxillectomy, are presented. The amount and exact placement of the grafts was determined preoperatively from the analysis of the three-dimensional CT reconstruction, and the surgical planning was thereby simplified.


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