The 2011 Tohoku megathrust earthquake had an unexpected size for the region. To image the earthquake rupture in detail, we applied a novel backprojection technique to waveforms from local accelerometer networks. The earthquake began as a small-size twin rupture, slowly propagating mainly updip and triggering the break of a larger-size asperity at shallower depths, resulting in up to 50 m slip a...

Measurements in nanoscopic imaging suffer from blurring effects concerning different point spread functions (PSF). Some apparatus even have PSFs that are locally dependent on phase shifts. Additionally, raw data are affected by Poisson noise resulting from laser sampling and "photon counts" in fluorescence microscopy. In these applications standard reconstruction methods (EM, filtered backproje...

conclusion safire reconstruction provided better coronary image quality and displayed the number, morphology, and surrounding lumen of calcium plaques more accurately than traditional fbp reconstruction, with safire3 achieving the best results. results the subjective ratings of image quality using safire1–safire5 reconstructions were significantly higher than those using fbp, with safire3 achie...

background: electronic portal imaging devices (epids) play an important role in radiation therapy portal imaging, geometric and dosimetric verifications. a successful utilization of epids for imaging and dosimetric purposes requires a reliable quality control process routine to be carried out regularly. in this study, two in-house phantoms were developed and analyzed for implementation in a qua...

We describe a computational method for depth extraction of three-dimensional (3D) objects using block matching for slice images in synthetic aperture integral imaging (SAII). SAII is capable of providing high-resolution 3D slice images for 3D objects because the picked-up elemental images are high-resolution ones. In the proposed method, the high-resolution elemental images are recorded by movi...

Over the last decades, there has been an increasing interest in dedicated preclinical imaging modalities for research biomedicine. Especially case of positron emission tomography (PET), reconstructed images provide useful information morphology and function internal organ. PET data, stored as sinograms, involve Radon transform image under investigation. The analytical approach to reconstruction...

In this paper, we propose an iterative beam hardening correction method that is applicable for the case with multiple materials. By assuming that the materials composing scanned object are known and that they are distinguishable by their linear attenuation coefficients at some given energy, the beam hardening correction problem is converted into a nonlinear system problem, which is then solved ...

In backprojection cone-beam CT the cone-beam projection images are first filtered, then 3D backprojected into the object space. In this paper the point spread function (PSF) for the filtering operation is studied. For the cases where the normalization matrix is a constant, i.e. all integration planes intersect the scan path the same number of times, the derivation of the PSF is extended to the ...

In this paper we propose a new approach of tomographic image reconstruction using sinogram interpolation for a sparse projection data. In this term, sinogram interpolation is a process of converting a sampled projection to a higher sampling rate projection. By using interpolation, we construct a new projections within the range of set of projection, then we apply a filtered backprojection recon...