Sökning: "backprojection"

Visar resultat 1 - 5 av 9 avhandlingar innehållade ordet backprojection.

1. 1. Inversion of circular averages and application of backprojection methods to radar imaging

   Författare :Stefan Nilsson; Linköpings universitet; []
   Nyckelord :inverse problem; backprojection; tomography; integral geometry;

   Sammanfattning : In this report we study two mathematical inverse problems concerning the determination of a function from spherical averages, which appear in certain radar applications. The first inverse problem consists of determining a function from its spherical averages over all circles with center on a straight line and with arbitrary radius. LÄS MER

3. 2. Iterative Filtered Backprojection Methods for Helical Cone-Beam CT

   Författare :Johan Sunnegårdh; Michael Felsberg; Michel Defrise; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Iterative reconstruction; filtered backprojection; regularization; cone-beam CT; Medical engineering; Medicinsk teknik;

   Sammanfattning : State-of-the-art reconstruction algorithms for medical helical cone-beam Computed Tomography (CT) are of type non-exact Filtered Backprojection (FBP). They are attractive because of their simplicity and low computational cost, but they produce sub-optimal images with respect to artifacts, resolution, and noise. LÄS MER

4. 3. Contribution to Wideband SAR Space-Time Processing, and Radar Remote Sensing of Sea Ice

   Författare :Mats I. Pettersson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; SAR; clutter suppression; space time adaptive processing; backprojection; remote sensing; moving target detection; radar scattering; Antenna array; wide band; sea ice;

   Sammanfattning : Synthetic Aperture Radar (SAR) has the capability to map the Earth with high resolution and is used in both civilian and military applications. The development of SAR systems is going towards higher resolution. Today there are Wide Band (WB) SAR instruments that have a resolution actually smaller than the operating wavelength. LÄS MER

5. 4. Ultra-wideband synthetic aperture radar in the VHF-band: Image formation algorithms and interferometric applications

   Författare :Per-Olov Frölind; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; backprojection; wideband; VHF; DEM; SAR; CARABAS; signal processing; low frequency; interferometry;

   Sammanfattning : Synthetic aperture radar (SAR) is a technology to generate high-resolution radar images for ground surveillance and mapping. By exploiting the lower VHF band, the attenuation reduces dramatically in forest areas compared to microwaves and new applications become feasible. LÄS MER

7. 5. Cone-Beam Reconstruction Using Filtered Backprojection

   Författare :Henrik Turbell; Per-Erik Danielsson; Michel Defrise; Linköpings universitet; []
   Nyckelord :TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : The art of medical computed tomography is constantly evolving and the last years have seen new ground breaking systems with multi-row detectors. These tomographs are able to increase both scanning speed and image quality compared to the single-row systems more commonly found in hospitals today. LÄS MER