Heritage Institute of Technology

About: Heritage Institute of Technology is a based out in . It is known for research contribution in the topics: Steganography & Support vector machine. The organization has 581 authors who have published 1045 publications receiving 8345 citations.

Images and Spectral Properties of Two Component Advective Flows Around Black Holes: Effects of Photon Bending

Abstract: Two component advective flow (TCAF) successfully explains spectral and timing properties of black hole candidates. We study the nature of photon trajectories in the vicinity of a Schwarzschild black hole and incorporate this in predicting images of TCAF with a black hole at the Centre. We also compute the emitted spectra. We employ a Monte-Carlo simulation technique to achieve our goal. For accurate prediction of the image and the spectra, null trajectories are generated without constraining the motion to any specific plane. Red shift, bolometric flux and corresponding temperature have been calculated with appropriate relativistic consideration. The centrifugal barrier dominated boundary layer or CENBOL near the inner region of the disk which acts as the Compton cloud is appropriately modelled as a thick accretion disk in Schwarzschild geometry for the purpose of imaging and computing spectra. The variations of spectra and image with physical parameters such as the accretion rate ($\dot{m}_d$) and inclination angle are presented. We show that the gravitational bending effects of photons do change the spectral shape to some extent.

Score level fusion of SIFT and SURF for iris

Abstract: Iris detection depending on local features like SIFT (Scale Invariant Feature Transform) and SURF (Speeded up Robust Features) exhibits high accuracy though the approaches leave behind further scope for improvement due to the lack of proper choice of score generating function and score fusion. Usually the score of a matching algorithm is taken to be number of matches. However a properly chosen function of number of matches can also be considered as a score. The proposed approach in this paper performs a classification operation on the detected keypoints. Each set of the keypoints of the query image is subjected to nearest neighbour match with respective set of keypoints of the database image. Hence there are two scores generated by the matching of two classes. This paper also proposes a mathematical monotonic function on these two scores to generate a single score such that the final score value gives rise to better disjunction between genuine and imposter scores than conventional SIFT.

Automatic Evaluation and Predictive Analysis of Optic Nerve Head for the Detection of Glaucoma

Abstract: The automatic retinal image analysis is emerging as one of the most important primary screening tools for early detection and treatment for eye diseases. Glaucoma is a severe human eye disease leading to the permanent loss of vision. The manual examination of optic nerve head of the retina using Color Fundus Imaging (CFI) is a standard procedure used for predicting glaucoma, but the detection and diagnosis varies widely across different ophthalmologists. In this paper we present an automatic technique for the segmentation of the cup region from the optical disc(OD) region in RGB channels to calculate the parameters used for the predictive analysis of glaucoma. The accurate segmentation of the cup region and the optical disc from the retinal fundus image serves as an important step for the calculation of cup-to-disc area ratio (ACDR). The quantitative evaluation of this predictive analysis is done on a freely available database with a result accuracy of 83.168%.

Images and spectra of time-dependent two-component advective flow in presence of outflows

Abstract: Two Component Advective Flow (TCAF) successfully explains the spectral and tem- poral properties of outbursting or persistent sources. Images of static TCAF with Compton cloud or CENtrifugal pressure supported Boundary Layer (CENBOL) due to gravitational bending of photons have been studied before. In this paper, we study time dependent images of advective flows around a Schwarzschild black hole which include cooling effects due to Comptonization of soft photons from a Keplerian disks well as the self-consistently produced jets and outflows. We show the overall image of the disk-jet system after convolving with a typical beamwidth. A long exposure image with time dependent system need not show the black hole horizon conspicuously, un- less one is looking at a soft state with no jet or the system along the jet axis. Assuming these disk-jet configurations are relevant to radio emitting systems also, our results would be useful to look for event horizons in high accretion rate Supermassive Black Holes in Seyfert galaxies, RL Quasars.