Novel FBP based sparse-view CT reconstruction scheme using self-shaping spatial filter based morphological operations and scaled reprojections

2021 ◽  
Vol 64 ◽  
pp. 102323
Author(s):  
Syed Muhammad Umar Talha ◽  
Tariq Mairaj ◽  
Waleed Bin Yousuf
Keyword(s):  
Spatial Filter ◽  
Morphological Operations ◽  
Ct Reconstruction ◽  
Reconstruction Scheme

Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

1972 ◽  
Vol 30 ◽  
pp. 596-597
Author(s):  
David A. Ansley
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Spatial Filter ◽  
Operating Conditions ◽  
Objective Lens ◽  
List Type ◽  
Spatial Filters ◽  
Transmission Electron ◽  
Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

Optimum spatial filter for optical defocus sensing

1981 ◽  
Vol 64 (9) ◽  
pp. 113-120
Author(s):  
Kohji Takemura ◽  
Suteo Tsutsumi
Keyword(s):  
Spatial Filter ◽  
Optical Defocus

Maisonneuve fracture

2020 ◽  
Vol 99 (2) ◽  
pp. 77-85
Keyword(s):  
Open Reduction ◽  
Lower Leg ◽  
Fracture Dislocation ◽  
Deltoid Ligament ◽  
Ct Reconstruction ◽  
Distal Fibula ◽  
Ct Examination ◽  
Maisonneuve Fracture ◽  
Fibular Fracture ◽  
Wide Range

Introduction: Maisonneuve fracture (MF) is a generally known entity in ankle trauma. However, details about this type of injury can be found only rarely in the literature. For these reasons we have decided to perform a study on MF epidemiology and pathoanatomy. Methods: The group comprised 70 patients (47 men, 23 women), with the mean age of 48 years, who sustained an ankle fracture-dislocation involving the proximal quarter of the fibula. Ankle radiographs in three views and lower leg radiographs in two views were performed in all patients. A total of 59 patients underwent CT examination in three views, including 3D CT reconstruction in 49 of these patients. MRI was performed in 4 patients. Operative treatment was used in 67 patients; open reduction of the distal fibula into the fibular notch was opted for in 54 of them. Results: The highest MF incidence rate was recorded in the 5th decade in the whole group and in men, while in women the peak incidence was in the 6th decade. After the age of 50, the share of women significantly increased. In 64 cases, the fibular fracture was subcapital, and in 6 cases it involved the fibular head. In 24% of the patients, the fibular fracture was seen only in the lateral radiograph of the lower leg. Widening of the tibiofibular clear space was shown by radiographs in 40 cases. Posterior dislocation of the fibula (Bosworth fracture) and tibiofibular diastasis were recorded in 2 cases each. An injury to the anterior and posterior tibiofibular ligaments was found in all 54 patients with open reduction of the distal fibula. A fracture of the medial malleolus was identified in 27 cases (39%) and a complete lesion of the deltoid ligament in 36 cases (51%); in 7 cases (10%) the medial structures were intact. A fracture of the posterior malleolus occurred in 54 (77%) patients. Osteochondral fracture of the talar dome was diagnosed in 2 patients and compression of the articular surface of the distal tibia in the region of the fibular notch in 1 patient. Conclusion: Maisonneuve fracture includes a wide range of injuries both to bone and ligamentous structures of the ankle. Therefore, CT examination is an indispensable part of assessment of this type of fracture.

Power Experimental Optimization of Horizontal Axis Wind Turbine

2020 ◽  
Vol 13 (3) ◽  
pp. 438-443
Author(s):  
Sadek Ameziane ◽  
Abdesselem Chikhi ◽  
Mohammed Salah Aggouner
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Energy System ◽  
Spatial Filter ◽  
Complex Model ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Detailed Model ◽  
Continuous Current ◽  
Mechanical Sensors

Background: The presented article is a contribution to the realization of a wind emulator based on a continuous-current machine. The development of this topic focuses on the modeling of a vertical axis wind turbine, a DC motor with independent excitation and its control via a chopper. Methods: To carry out this work, we have studied and designed the electronic and mechanical sensors as well as a command implemented on the dSPACE DS1103 system. Results: The main purpose of this work is related, on one hand, to the control of the motor turbine by imposing the wind profile and on the other hand generate the command of the implanted MPPT. The experimental results obtained showed the great performances which characterize this improved wind energy system. Conclusion: Finally, a wind turbine with variable speed is a system having a complex model; however, a detailed model of the interaction between the wind and the aero-turbine is useful to understand certain phenomena such as rotational sampling or the spatial filter.

Face detection in single and multiple images using different skin color models

2020 ◽  
Vol 13 ◽  
Author(s):  
Manpreet Kaur ◽  
Jasdev Bhatti ◽  
Mohit Kumar Kakkar ◽  
Arun Upmanyu
Keyword(s):  
Face Detection ◽  
Skin Color ◽  
Input Image ◽  
Morphological Operations ◽  
Reliability Model ◽  
Multiple Images ◽  
Face Region ◽  
Bounding Box ◽  
The Face ◽  
Precision And Accuracy

Introduction: Face Detection is used in many different steams like video conferencing, human-computer interface, in face detection, and in the database management of image. Therefore, the aim of our paper is to apply Red Green Blue ( Methods: The morphological operations are performed in the face region to a number of pixels as the proposed parameter to check either an input image contains face region or not. Canny edge detection is also used to show the boundaries of a candidate face region, in the end, the face can be shown detected by using bounding box around the face. Results: The reliability model has also been proposed for detecting the faces in single and multiple images. The results of the experiments reflect that the algorithm been proposed performs very well in each model for detecting the faces in single and multiple images and the reliability model provides the best fit by analyzing the precision and accuracy. Moreover Discussion: The calculated results show that HSV model works best for single faced images whereas YCbCr and TSL models work best for multiple faced images. Also, the evaluated results by this paper provides the better testing strategies that helps to develop new techniques which leads to an increase in research effectiveness. Conclusion: The calculated value of all parameters is helpful for proving that the proposed algorithm has been performed very well in each model for detecting the face by using a bounding box around the face in single as well as multiple images. The precision and accuracy of all three models are analyzed through the reliability model. The comparison calculated in this paper reflects that HSV model works best for single faced images whereas YCbCr and TSL models work best for multiple faced images.

Spatial filtering of signals with spectrum overlapping

2019 ◽  
pp. 27-33
Author(s):  
M. E. Shevchenko ◽  
A. V. Gorovoy ◽  
S. N. Solovyov
Keyword(s):  
Antenna Arrays ◽  
A Priori ◽  
Spatial Filtering ◽  
Spatial Filter ◽  
Radio Sources ◽  
Probability Of Error ◽  
Shift Keying ◽  
A Priori Uncertainty

The paper considers the spatial filtering methods of signals with spectrum overlapping under conditions of a priori uncertainty of the directions of arrival from radio sources. The estimates of the directions of signals arrival obtained by ESPRIT or MUSIC are used in order to build a spatial filter. It is shown that when using ESPRIT, unlike MUSIC, an additional calculations of filter coefficients based on estimates of the directions of signals arrival are not required, and the quadrature components of the signals are formed simultaneously with estimates of the direction of their arrival. The probability of error performances of minimum shift keying signals which were divided by spatial filtering on the basis of ESPRIT and MUSIC using seven-element circular and angular antenna arrays are given.

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