in the form of passive seismic methods, broadband seismometers have been used in hydrocarbon exploration. the frequency bandwidth typically studied is in the range of 1–6 hz. the observations on low frequency band of microtremors are used to calculate the spectral ratio of vertical and horizontal components (v/h) and power spectral density (psd). attributes based on the v/h ratio and the psd ha...

The noise in reconstructed slices of X-ray Computed Tomography (CT) is of unknown distribution, non-stationary, oriented and difficult to distinguish from main structural information. This requires the development of special post-processing methods based on the local statistical evaluation of the noise component. This paper presents an adaptive method of reducing noise in CT images employing th...

 Edge Detection is an important task for sharpening the boundary of images to detect the region of interest. This paper applies a linear cellular automata rules and a Mamdani Fuzzy inference model for edge detection in both monochromatic and the RGB images. In the uniform cellular automata a transition matrix has been developed for edge detection. The Results have been compared to the ...

We present a monitoring study of SN 2004A and probable discovery of a progenitor star in pre-explosion HST images. The photometric and spectroscopic monitoring of SN 2004A show that it was a normal Type II-P which was discovered in NGC 6207 about two weeks after explosion. We compare SN 2004A to the similar Type II-P SN 1999em and estimate an explosion epoch of 2004 January 6. We also calculate...

High time resolution spectroscopic observations of the ultra-compact helium dwarf nova ‘SN 2003aw’ in its quiescent state at V ∼ 20.5 reveal its orbital period at 2027.8±0.5 seconds or 33.80 minutes. Together with the photometric “superhump” period of 2041.5±0.5 seconds, this implies a mass ratio q≈ 0.036. We compare both the average and time-resolved spectra of ‘SN 2003aw’ and SDSS J124058.03−...

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...