We present a technique for automatic detection of drainage channel networks on digital images acquired by conventional satellites such as LANDSAT and SPOT. Since these satellites are sun{synchronous, the approximate local sun angle at time of image acquisition is always known. Consequently, the spatial behavior of shading with respect to channels and other topo-morphologic features is known. Th...

I n this paper we tackle the problem of magnifying an image without incurring blurring, ringing or other artifacts common to classical schemes. The proposed iterative scheme starts with an initial magnified image generated by a process of selective interpolation. By placing suitable constraints on the final magnified image, which are convex in nature, we show that magnification can be posed as ...

Most halftoning techniques have been primarily concerned with achieving an accurate reproduction of local grayscale intensities while avoiding the introduction of artifacts. A secondary concern in halftoning has been the preservation of edges in the halftoned image. In this paper, we will introduce a new halftoning technique that utilizes a bandpass pyramid to achieve an accurate reproduction o...

In this paper, we have used the immersed boundary method to solve the two-dimensional Navier-Stokes equations for two immersed wings performing an idealized 'clap and fling' stroke and a 'fling' half-stroke. We calculated lift coefficients as functions of time per wing for a range of Reynolds numbers (Re) between 8 and 128. We also calculated the instantaneous streamlines around each wing throu...

In the present research, a unified formulation for free vibration analysis of the bidirectional functionally graded conical and cylindrical shells and annular plates on elastic foundations is developed. To cover more individual cases and optimally tailored material properties, the material properties are assumed to vary in both the meridian/radial and transverse directions. The shell/plate is a...

BACKGROUND Retina degenerative disorders represent the primary cause of blindness in UK and in the developed world. In particular, Age Related Macular Degeneration (AMD) and Retina Pigmentosa (RP) diseases are of interest to this study. We have therefore created new image processing algorithms for enhancing the visual scenes for them. METHODS In this paper we present three novel image enhance...

Extended permutation (EP) lters are deened and analyzed in this paper. In particular, we focus on extended permutation rank selection (EPRS) lters. These lters are constrained to output an order statistic from an extended observation vector. This extended vector includes N observation samples and K statistics that are functions of the observation samples. The rank permutations from selected sam...

one of the most fundamental features of digital image and the basic steps in image processing, analysis, pattern recognition and computer vision is the edge of an image where the preciseness and reliability of its results will affect directly on the comprehension machine system made objective world. several edge detectors have been developed in the past decades, although no single edge detector...

For decades, image enhancement has been considered one of the most important aspects in computer science because of its influence on a number of fields including but not limited to medical, security, banking and financial sectors. In this paper, a new gray level image (edge preserving) enhancement method called the harmony search algorithm (HSA) is proposed. HSA is a recently introduced populat...

Abstract Based on the radial Hilbert transform of spatial filtering and electro-optical sampling, we propose a broadband terahertz edge-enhanced imaging method in this work. Instead using narrow-band THz vortex phase plate, here use ultrashort laser pulse to realize enhancement which can be applied for few-cycle imaging. The principle edge is analyzed theoretically, analytical expression final ...