Dibyendu Nandy

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A novel method for representing 3-D objects that uni es viewer and model centered object representations is presented. A uni ed 3-D frequency-domain representation (called Volumetric Frequency Representation VFR) encapsulates both the spatial structure of the object and a continuum of its views in the same data structure. The frequency-domain image of an(More)
A novel generalized feature extraction method based on the expansion matching (EXM) method and on the Karhunen-Loeve transform (KLT) is presented. The method provides an efficient way to locate complex features of interest like corners and junctions with reduced number of filtering operations. The EXM method is used to design optimal detectors for a set of(More)
We explore a two-dimensional kinematic solar dynamo model in a full sphere, based on the helioseismically determined solar rotation profile and with an α effect concentrated near the solar surface, which captures the Babcock-Leighton idea that the poloidal field is created from the decay of tilted bipolar active regions. The meridional circulation, assumed(More)
A computational model of auditory localization based on processing spectral amplitude cues for localizing broadband high frequency sound sources is presented. The cues extracted are binaural spectral level di erence patterns of the Head Related Transfer Functions (HRTF) corresponding to the direction of the sound source. Four di erent pattern classi ers are(More)
We develop a model of the solar dynamo in which, on the one hand, we follow the Babcock–Leighton approach to include surface processes like the production of poloidal field from the decay of active regions, and, on the other hand, we attempt to develop a mean field theory that can be studied in quantitative detail. One of the main challenges in developing(More)
In this paper, we develop a novel framework for robust recovery of three-dimensional (3-D) surfaces of faces from single images. The underlying principle is shape from recognition, i.e., the idea that pre-recognizing face parts can constrain the space of possible solutions to the image irradiance equation, thus allowing robust recovery of the 3-D structure(More)
An essential ingredient in kinematic dynamo models of the solar cycle is the internal velocity field within the simulation domain – the solar convection zone. In the last decade or so, the field of helioseismology has revolutionized our understanding of this velocity field. In particular, the internal differential rotation of the Sun is now fairly well(More)
Sunspots, dark magnetic regions occurring at low latitudes on the Sun's surface, are tracers of the magnetic field generated by the dynamo mechanism. Recent solar dynamo models, which use the helioseismically determined solar rotation, indicate that sunspots should form at high latitudes, contrary to observations. We present a dynamo model with the correct(More)
In this work, a framework for the reconstruction of smooth surface shapes from shading images is presented. The method is based on using a backpropagation based neural network for learning brightness patterns and associating them with range data. The network is designed to reconstruct surface range from localized intensity patches of pixels. Two methods for(More)
We present in this paper a connectionist model that extracts interaural intensity differences (IID) from head-related transfer functions (HRTF) in the form of spectral cues to localize broadband high-frequency auditory stimuli, in both azimuth and elevation. A novel discriminative matching measure (DMM) is defined and optimized to characterize matching this(More)