The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform

Ronald J. Giovan - One of the best experts on this subject based on the ideXlab platform.

  • Pressure-Controlled Atomization Process (PCAP) for Dimensional Restoration of Aviation Parts. Part 2.
    1996
    Co-Authors: John C. Tierney, Ronald J. Giovan
    Abstract:

    Abstract : The Pressure-controlled Atomization Process (PCAP) is a new thermal spray process in which a metal is atomized in a supersonic nozzle, which also directs the spray to a suitable substrate. The Casting Project was jointly sponsored by the United States Air Force, Armstrong Laboratory Environics Directorate at Tyndall AFB, and the United States Department of Energy, Office of Technology Development (OTD) under the U. S. Air Force - DOE Memorandum of Understanding (MOU). The Air Force application the Pressure Controlled Atomization Process (PCAP) to thermally spray metallic replacement coatings for - hard chromium. The report presents a history of PCAP as it relates to the development of the process, the development of the hardware to support the process development, and the testing that was conducted to understand the process and generate engineering data to support the replacement hard chromium electroplating with PCAP sprayed coating.

  • Pressure-Controlled Atomization Process (PCAP) for Dimensional Restoration of Aviation Parts. Part 1.
    1996
    Co-Authors: John C. Tierney, Ronald J. Giovan
    Abstract:

    Abstract : The Pressure-Controlled Atomization Process (PCAP) is a new thermal spray process in which a liquid metal is atomized in a supersonic nozzle, which also directs the spray to a suitable substrate. The Spray Casting Project was jointly sponsored by the United States Air Force, Armstrong Laboratory Environics Directorate at Tyndall AFB, and the United States Department of Energy, Office of Technology Development (DOE-OTD) under the U.S. Air Force-DOE Memorandum of Understanding (MOU). The Air Force application uses the Pressure Controlled Atomization Process (PCAP) to thermally spray metallic replacement coatings for electroplated hard chromium. The report presents a history of PCAP as it relates to the development of the process, the development of the hardware to support the process development and the testing that was conducted to understand the process and generate engineering data to support the replacement hard chromium electroplating with PCAP sprayed coatings.

D. Boulfelfel - One of the best experts on this subject based on the ideXlab platform.

  • Two-Dimensional Restoration of single photon emission computed tomography images using the Kalman filter
    IEEE Transactions on Medical Imaging, 1994
    Co-Authors: D. Boulfelfel, R.m. Rangayyan, L.j. Hahn, R. Kloiber, G.r. Kuduvalli
    Abstract:

    The discrete filtered backprojection (DFBP) algorithm used for the reconstruction of single photon emission computed tomography (SPECT) images affects image quality because of the operations of filtering and discretization. The discretization of the filtered backprojection process can cause the modulation transfer function (MTF) of the SPECT imaging system to be anisotropic and nonstationary, especially near the edges of the camera's field of view. The use of shift-invariant Restoration techniques fails to restore large images because these techniques do not account for such variations in the MTF. This study presents the application of a two-Dimensional (2D) shift-variant Kalman filter for post-reconstruction Restoration of SPECT slices. This filter was applied to SPECT images of a hollow cylinder phantom; a resolution phantom; and a large, truncated cone phantom containing two types of cold spots, a sphere, and a triangular prism. The images were acquired on an ADAC GENESYS camera. A comparison was performed between results obtained by the Kalman filter and those obtained by shift-invariant filters. Quantitative analysis of the restored images performed through measurement of root mean squared errors shows a considerable reduction in error of Kalman-filtered images over images restored using shift-invariant methods.

  • Three-Dimensional Restoration of single photon emission computed tomography images
    IEEE Transactions on Nuclear Science, 1994
    Co-Authors: D. Boulfelfel, R.m. Rangayyan, L.j. Hahn, R. Kloiber
    Abstract:

    Restoration of single photon emission computed tomography (SPECT) images is usually performed either on two-Dimensional (2-D) projection images (pre-reconstruction Restoration) or on SPECT slices (post-reconstruction Restoration). This study presents the application of a three-Dimensional (3-D) filter in restoring SPECT images. The 3-D filter is shown to perform better than the 2-D methods because it takes into consideration the interslice information in the filtering process and has a relatively space-invariant blur function. To reduce the space-variance of the 3-D point spread function (PSF), conjugate projections were combined by geometric averaging before reconstruction. We investigated the potential of 3-D Wiener and power spectrum equalization (PSE) filters. These filters were applied to SPECT images of a resolution phantom and a large, truncated cone phantom containing two types of cold spots: a sphere, and a triangular prism. The filters were also applied to clinical images of the liver and spleen. The images were acquired on an ADAC GENESYS camera. A comparison was performed between results obtained in this study and those obtained by 2-D pre-reconstruction Restoration and 2-D post-reconstruction Restoration filters. Quantitative analysis of the 3-D restored images performed through measurement of root mean squared (RMS) errors and contrast ratios showed a considerable reduction in error and increase in contrast over images restored using the two other methods.

  • Three-Dimensional Restoration of single photon emission computed tomography images
    Conference Record of the 1991 IEEE Nuclear Science Symposium and Medical Imaging Conference, 1991
    Co-Authors: D. Boulfelfel, R.m. Rangayyan, L.j. Hahn, R. Kloiber
    Abstract:

    A 3-D filter was used for restoring SPECT (single photon emission computed tomography) images. The 3-D filter is shown to perform better than 2-D methods because it takes into consideration the interslice information in the filtering process and has a relatively space-invariant blur function. The potential of 3-D Wiener and power spectrum equalization filters was investigated. These filters were applied to SPECT images of a large, truncated conic phantom containing two types of cold spots, a sphere, and a triangular prism. The images were acquired on an ADAC GENESYS camera. A comparison was performed between results obtained in this study and those obtained by 2-D pre-reconstruction Restoration and 2-D post-reconstruction Restoration filters. Quantitative analysis of the 3-D restored images performed through measurement of root-mean-square errors and contrast ratios shows a considerable reduction in error and increase in contrast over images restored using the two other methods.

John C. Tierney - One of the best experts on this subject based on the ideXlab platform.

  • Pressure-Controlled Atomization Process (PCAP) for Dimensional Restoration of Aviation Parts. Part 2.
    1996
    Co-Authors: John C. Tierney, Ronald J. Giovan
    Abstract:

    Abstract : The Pressure-controlled Atomization Process (PCAP) is a new thermal spray process in which a metal is atomized in a supersonic nozzle, which also directs the spray to a suitable substrate. The Casting Project was jointly sponsored by the United States Air Force, Armstrong Laboratory Environics Directorate at Tyndall AFB, and the United States Department of Energy, Office of Technology Development (OTD) under the U. S. Air Force - DOE Memorandum of Understanding (MOU). The Air Force application the Pressure Controlled Atomization Process (PCAP) to thermally spray metallic replacement coatings for - hard chromium. The report presents a history of PCAP as it relates to the development of the process, the development of the hardware to support the process development, and the testing that was conducted to understand the process and generate engineering data to support the replacement hard chromium electroplating with PCAP sprayed coating.

  • Pressure-Controlled Atomization Process (PCAP) for Dimensional Restoration of Aviation Parts. Part 1.
    1996
    Co-Authors: John C. Tierney, Ronald J. Giovan
    Abstract:

    Abstract : The Pressure-Controlled Atomization Process (PCAP) is a new thermal spray process in which a liquid metal is atomized in a supersonic nozzle, which also directs the spray to a suitable substrate. The Spray Casting Project was jointly sponsored by the United States Air Force, Armstrong Laboratory Environics Directorate at Tyndall AFB, and the United States Department of Energy, Office of Technology Development (DOE-OTD) under the U.S. Air Force-DOE Memorandum of Understanding (MOU). The Air Force application uses the Pressure Controlled Atomization Process (PCAP) to thermally spray metallic replacement coatings for electroplated hard chromium. The report presents a history of PCAP as it relates to the development of the process, the development of the hardware to support the process development and the testing that was conducted to understand the process and generate engineering data to support the replacement hard chromium electroplating with PCAP sprayed coatings.

R. Kloiber - One of the best experts on this subject based on the ideXlab platform.

  • Two-Dimensional Restoration of single photon emission computed tomography images using the Kalman filter
    IEEE Transactions on Medical Imaging, 1994
    Co-Authors: D. Boulfelfel, R.m. Rangayyan, L.j. Hahn, R. Kloiber, G.r. Kuduvalli
    Abstract:

    The discrete filtered backprojection (DFBP) algorithm used for the reconstruction of single photon emission computed tomography (SPECT) images affects image quality because of the operations of filtering and discretization. The discretization of the filtered backprojection process can cause the modulation transfer function (MTF) of the SPECT imaging system to be anisotropic and nonstationary, especially near the edges of the camera's field of view. The use of shift-invariant Restoration techniques fails to restore large images because these techniques do not account for such variations in the MTF. This study presents the application of a two-Dimensional (2D) shift-variant Kalman filter for post-reconstruction Restoration of SPECT slices. This filter was applied to SPECT images of a hollow cylinder phantom; a resolution phantom; and a large, truncated cone phantom containing two types of cold spots, a sphere, and a triangular prism. The images were acquired on an ADAC GENESYS camera. A comparison was performed between results obtained by the Kalman filter and those obtained by shift-invariant filters. Quantitative analysis of the restored images performed through measurement of root mean squared errors shows a considerable reduction in error of Kalman-filtered images over images restored using shift-invariant methods.

  • Three-Dimensional Restoration of single photon emission computed tomography images
    IEEE Transactions on Nuclear Science, 1994
    Co-Authors: D. Boulfelfel, R.m. Rangayyan, L.j. Hahn, R. Kloiber
    Abstract:

    Restoration of single photon emission computed tomography (SPECT) images is usually performed either on two-Dimensional (2-D) projection images (pre-reconstruction Restoration) or on SPECT slices (post-reconstruction Restoration). This study presents the application of a three-Dimensional (3-D) filter in restoring SPECT images. The 3-D filter is shown to perform better than the 2-D methods because it takes into consideration the interslice information in the filtering process and has a relatively space-invariant blur function. To reduce the space-variance of the 3-D point spread function (PSF), conjugate projections were combined by geometric averaging before reconstruction. We investigated the potential of 3-D Wiener and power spectrum equalization (PSE) filters. These filters were applied to SPECT images of a resolution phantom and a large, truncated cone phantom containing two types of cold spots: a sphere, and a triangular prism. The filters were also applied to clinical images of the liver and spleen. The images were acquired on an ADAC GENESYS camera. A comparison was performed between results obtained in this study and those obtained by 2-D pre-reconstruction Restoration and 2-D post-reconstruction Restoration filters. Quantitative analysis of the 3-D restored images performed through measurement of root mean squared (RMS) errors and contrast ratios showed a considerable reduction in error and increase in contrast over images restored using the two other methods.

  • Three-Dimensional Restoration of single photon emission computed tomography images
    Conference Record of the 1991 IEEE Nuclear Science Symposium and Medical Imaging Conference, 1991
    Co-Authors: D. Boulfelfel, R.m. Rangayyan, L.j. Hahn, R. Kloiber
    Abstract:

    A 3-D filter was used for restoring SPECT (single photon emission computed tomography) images. The 3-D filter is shown to perform better than 2-D methods because it takes into consideration the interslice information in the filtering process and has a relatively space-invariant blur function. The potential of 3-D Wiener and power spectrum equalization filters was investigated. These filters were applied to SPECT images of a large, truncated conic phantom containing two types of cold spots, a sphere, and a triangular prism. The images were acquired on an ADAC GENESYS camera. A comparison was performed between results obtained in this study and those obtained by 2-D pre-reconstruction Restoration and 2-D post-reconstruction Restoration filters. Quantitative analysis of the 3-D restored images performed through measurement of root-mean-square errors and contrast ratios shows a considerable reduction in error and increase in contrast over images restored using the two other methods.

G.r. Kuduvalli - One of the best experts on this subject based on the ideXlab platform.

  • Two-Dimensional Restoration of single photon emission computed tomography images using the Kalman filter
    IEEE Transactions on Medical Imaging, 1994
    Co-Authors: D. Boulfelfel, R.m. Rangayyan, L.j. Hahn, R. Kloiber, G.r. Kuduvalli
    Abstract:

    The discrete filtered backprojection (DFBP) algorithm used for the reconstruction of single photon emission computed tomography (SPECT) images affects image quality because of the operations of filtering and discretization. The discretization of the filtered backprojection process can cause the modulation transfer function (MTF) of the SPECT imaging system to be anisotropic and nonstationary, especially near the edges of the camera's field of view. The use of shift-invariant Restoration techniques fails to restore large images because these techniques do not account for such variations in the MTF. This study presents the application of a two-Dimensional (2D) shift-variant Kalman filter for post-reconstruction Restoration of SPECT slices. This filter was applied to SPECT images of a hollow cylinder phantom; a resolution phantom; and a large, truncated cone phantom containing two types of cold spots, a sphere, and a triangular prism. The images were acquired on an ADAC GENESYS camera. A comparison was performed between results obtained by the Kalman filter and those obtained by shift-invariant filters. Quantitative analysis of the restored images performed through measurement of root mean squared errors shows a considerable reduction in error of Kalman-filtered images over images restored using shift-invariant methods.