Focal spot size is one of the crucial factors that affect the image quality of any x-ray imaging system. It is, therefore, important to measure the focal spot size accurately. In the past, pinhole and slit measurements of x-ray focal spots were obtained using direct exposure film. At present, digital detectors are replacing film in medical imaging so that, although focal spot measurements can b...

Synopsis This chapter presents x-ray image quality optimization techniques using digital phantom images and computerized observer models. The X-ray imaging parameters are optimized so as to maximize tumor detectability while minimizing the patient dose. Digital phantoms are generated using the virtual photographic and radiographic imaging simulator (ViPRIS) package. ViPRIS uses a tomographic ph...

in this paper a novel fuzzy scheme for medical x-ray image classification is presented. in this method, any image is partitioned in to 25 overlapping subimages and then shape-texture features are extracted from shape and directional information extracted from any subimage. in the classification stage, we apply a fuzzy membership to any subimage with respect to euclidean distance between feature...

The Sloan Digital Sky Survey (SDSS) quasars at redshift z ≈ 6 (Fan et al. 2001) are the most distant condensed objects known in the universe. X-ray observations of them are of great importance; e.g., to study the cosmic time evolution of X-ray emission and to assess the detectability of quasar X-ray emission at even larger redshifts. All three quasars were easily detected in X-rays even in thes...

To enable tissue function-based tumor diagnosis over the large number of existing digital mammography systems worldwide, we propose a cost-effective and robust approach to incorporate tomographic optical tissue characterization with separately acquired digital mammograms. Using a flexible contour-based registration algorithm, we were able to incorporate an independently measured two-dimensional...

Single-photon counting hybrid pixel detectors have shown to be a valid alternative to other types of X-ray imaging devices due to their high sensitivity, low noise, linear behavior and wide dynamic range. One important advantage of these devices is the fact that detector and readout electronics are manufactured separately. This allows the use of industrial state-of-the-art CMOS processes to mak...

Medical imaging is the principal method for noninvasively obtaining anatomic and physiologic information about the human body. Imaging has experienced a quantum leap in technology and clinical applications over the past 25 years. This leap includes x-ray computed tomography (CT); emission computed tomography (SPECT and PET); magnetic-resonance imaging (MRI) and spectroscopy (MRS), including fun...

Single-photon counting hybrid pixel detectors have shown to be a valid alternative to other types of X-ray imaging devices due to their high sensitivity, low noise, linear behavior and wide dynamic range. One important advantage of these devices is the fact that detector and readout electronics are manufactured separately. This allows the use of industrial state-of-the-art CMOS processes to mak...

We have investigated the magnetic properties of a GaN/Ga1−xMnxN (x = 0.1) digital ferromagnetic heterostructure (DFH) showing ferromagnetic behavior using soft x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD). The Mn L2,3-edge XAS spectra were similar to those of Ga1−xMnxN random alloy thin films, indicating a substitutional doping of high concentration Mn into G...

The anti-scatter grid is generally used as a way of eliminating scattered radiation from X-ray photographs. This does not change even if the detector system changes from an analogue system to a digital system such as the flat-panel detector. We developed a new method that uses software to eliminate scatter components from digital X-ray images taken without the use of an anti-scatter grid. With ...