Kernel Flow:a high channel count scalable time-domain functional near-infrared spectroscopy system

Significance: Time-domain functional near-infrared spectroscopy (TD-fNIRS) has been considered as the gold standard of noninvasive optical brain imaging devices. However, due to the high cost, complexity, and large form factor, it has not been as widely adopted as continuous wave NIRS systems. Aim: Kernel Flow is a TD-fNIRS system that has been designed to break through these limitations by maintaining the performance of a research grade TD-fNIRS system while integrating all of the components into a small modular device. Approach: The Kernel Flow modules are built around miniaturized laser drivers, custom integrated circuits, and specialized detectors. The modules can be assembled into a system with dense channel coverage over the entire head. Results: We show performance similar to benchtop systems with our miniaturized device as characterized by standardized tissue and optical phantom protocols for TD-fNIRS and human neuroscience results. Conclusions: The miniaturized design of the Kernel Flow system allows for broader applications of TD-fNIRS.</p

Models for visual saliency in images and videos

Multimedia data consisting of videos and images are in general very rich in content and carry lot of information. With the digital cameras and camcorders becoming easily available to consumers, the amount of information in the form of multimedia data stored and shared across web has increased exponentially. Human beings are normally interested only in a ’subset’ of this information available in images and videos, which they consider as salient. Given the huge amount of data to be processed, it is important to obtain information regarding the regions in an image or video which attract human attention so that the overhead of redundant data can be greatly reduced in multimedia applications. The detection of such salient regions or objects in images and videos is the objective of the proposed research work.DOCTOR OF PHILOSOPHY (SCE

A linear dynamical system framework for salient motion detection

Detection of salient motion in a video involves determining which motion is attended to by the human visual system in the presence of background motion that consists of complex visuals that are constantly changing. Salient motion is marked by its predictability compared to the more complex unpredictable motion of the background such as fluttering of leaves, ripples in water, dispersion of smoke, and others. We introduce a novel approach to detect salient motion based on the concept of “observability” from the output pixels, when the video sequence is represented as a linear dynamical system. The group of output pixels with maximum saliency is further used to model the holistic dynamics of the salient region. The pixel saliency map is bolstered by two region-based saliency maps, which are computed based on the similarity of dynamics of the different spatiotemporal patches in the video with the salient region dynamics, in a global as well as a local sense. The resulting algorithm is tested on a set of challenging sequences and compared to state-of-the-art methods to showcase its superior performance on grounds of its computational efficiency and ability to detect salient motion

Rhodium-catalysed reduction of vanadium pentoxide and tungsten trioxide by hydrogen

Hydrogen reduction of V<SUB>2</SUB>O<SUB>5</SUB> and WO<SUB>3</SUB> catalysed by rhodium, both in the pure form and supported on kieselguhr, has been studied. The products obtained at 300°C have been identified as VO<SUB>2</SUB> and H<SUB>x</SUB>WO<SUB>3</SUB>. In situ electrical resistivity measurements on V<SUB>2</SUB>O<SUB>5</SUB> pellets, both pure and admixed with the catalyst, show an anomalous resistance increase with temperature, perhaps arising from chemisorption and spillover of hydrogen from rhodium

Search for bursts of gamma rays of energies > 1 GeV

A ground-based experiment to detect cosmic gamma-ray bursts (GRB) in which the individual gamma-rays at the top of the atmosphere have energies in the GeV range has been in operation at Ootacamund, India, for nearly 1.5 years. Not a single event was observed, although five of the GRB seen by satellite-borne detectors in the MeV energy range were in the view of and potentially observable by our experiment. Details of the experimental results and their implications to the phenomenon of GRB are presented. The experiment also enables us to place a 99 per cent confidence level upper limit to the rate of explosions of primordial black holes (Hawking process) in the vicinity of the solar system at a value of 1.6 × 103 or 5.7 × 103/ (yr pc+3), depending on whether the explosions take place according to an elementary or a composite particle hypothesis, respectively