This paper presents the hardware implementation of a stand-alone Electrical Capacitance Tomography (ECT) system employing a Field Programmable Gate Array (FPGA). The image reconstruction algorithms of the ECT system d...
详细信息
This paper presents the hardware implementation of a stand-alone Electrical Capacitance Tomography (ECT) system employing a Field Programmable Gate Array (FPGA). The image reconstruction algorithms of the ECT system demand intensive computation and fast processing of large number of measurements. The inner product of large vectors is the core of the majority of these algorithms. Therefore, a reconfigurable segmented parallel inner product architecture for the parallel matrix multiplication is proposed. In addition, hardware-software codesign targeting FPGA System-On-Chip (SoC) is applied to achieve high performance. The development of the hardware-software codesign is carried out via commercial tools to adjust the software algorithms and parameters of the system. The ECT system is used in this work to monitor the characteristic of the molten metal in the Lost Foam Casting (LFC) process. The hardware system consists of capacitive sensors, wireless nodes and FPGA module. The experimental results reveal high stability and accuracy when building the ECT system based on the FPGA architecture. The proposed system achieves high performance in terms of speed and small design density.
Background: This report describes the results of clinical, ultrasonographic and computed tomographic examination of a 16-year-old goat with extraskeletal osteosarcoma of the thorax. Case presentation: The lead clinica...
详细信息
Background: This report describes the results of clinical, ultrasonographic and computed tomographic examination of a 16-year-old goat with extraskeletal osteosarcoma of the thorax. Case presentation: The lead clinical signs were abnormal condition and demeanour, fever, tachycardia, tachypnoea, dyspnoea and dilated jugular veins. Ultrasonographic examination of the thorax revealed a precardial mass, measuring 16.4 by 11.4 by 14.2 cm. Computed tomographic examination showed dorsocaudal displacement of the trachea, heart and lungs to the right. A tentative diagnosis of mediastinal or pleural neoplasia was made, and the goat was euthanased and necropsied. A definitive diagnosis was based on histological examination of the mass. Conclusions: To our knowledge, this case report is the first description of extraskeletal osteosarcoma of the thorax in goats and serves to broaden the diagnostic spectrum of thoracic diseases in this species. Extraskeletal osteosarcoma should be part of the differential diagnosis in goats with thoracic tumours.
To solve ill-posed problem and poor resolution in electrical capacitance tomography (ECT),a new image reconstruction algorithm based on total variation(TV)regularization is proposed and a new self-adaptive mesh refine...
详细信息
To solve ill-posed problem and poor resolution in electrical capacitance tomography (ECT),a new image reconstruction algorithm based on total variation(TV)regularization is proposed and a new self-adaptive mesh refinement strategy is put *** with the conventional Tikhonov regularization,this new algorithm not only stabilizes the reconstruction,but also enhances the distinguishability of the reconstructionimage in areas with discontinuous medium distribution.R possesses a good edge-preserving *** self-adaptive mesh generation technique based on this algorithm can refine the mesh automatically in specific areas according to medium *** strategy keeps high resolution as refining all elements over the region but reduces calculation loads,thereby speeds up the *** simulation and experimental results show that this algorithm has advantages in terms of the resolution and real-time performance.
Electrical impedance tomography (EIT) provides low-resolution images of internal conductivity distributions, but is able to achieve relatively high temporal resolutions. Most EIT image reconstruction algorithms do not...
详细信息
Electrical impedance tomography (EIT) provides low-resolution images of internal conductivity distributions, but is able to achieve relatively high temporal resolutions. Most EIT image reconstruction algorithms do not explicitly account for the temporal constraints on the measurements or physiological processes under investigation. Instead, algorithms typically assume both that the conductivity distribution does not change during the acquisition of each EIT data frame, and that frames can be reconstructed independently, without consideration of the correlation between images. A failure to account for these temporal effects will result in aliasing-related artefacts in images. Several methods have been proposed to compensate for these effects, including interpolation of raw data, and reconstructionalgorithms using Kalman and temporal filtering. However, no systematic work has been performed to understand the severity of the temporal artefacts nor the extent to which algorithms can account for them. We seek to address this need by developing a temporal comparison framework and figures of merit to assess the ability of reconstructionalgorithms to account for temporal effects. Using this approach, we compare combinations of three reconstructionalgorithms using three EIT data frame types: perfect, realistic and interpolated. The results show that, without accounting for temporal effects, artefacts are present in images for dynamic conductivity contrasts at frequencies 10-20 times slower than the frame rate. The proposed methods show some improvements in reducing these artefacts.
In the Electrical Capacitance Tomography, the distribution of permittivity in the pipe can be estimated using the capacitance measurements with help of the reconstructionalgorithms. In this paper, the permittivity di...
详细信息
ISBN:
(纸本)9781467390996
In the Electrical Capacitance Tomography, the distribution of permittivity in the pipe can be estimated using the capacitance measurements with help of the reconstructionalgorithms. In this paper, the permittivity distribution was reconstructed with Kalman Filter and several simulations were carried out to evaluate the effect of different initial values of the grey values in the image and the estimate error covariance on reconstructed image. In addition, Landweber and Tikhonov were used to reconstruct the object to compare with the reconstructed effect of Kalman Filter with suitable initial values.
暂无评论