ABSTRACT: In this paper, the thermal characteristics of single and double flow plane solar heaters with radiating working gas were analyzed and compared by numerical analysis for the first time. The laminar mixed convection gas flow in the heaters was numerically simulated by the CFD method using the finite volume technique. The set of governing equations included the conservation of mass, mome...

The purpose of the present text is to present the theory and techniques behind the Gray Level Coocurrence Matrix (GLCM) method, and the stateof-the-art of the field, as applied to two dimensional images. It does not present a survey of practical results. 1 Gray Level Coocurrence Matrices In statistical texture analysis, texture features are computed from the statistical distribution of observed...

One method to estimate image values in the presence of noise and discontinuities is to try all possible configurations of discontinuities in a neighborhood, and then select the one that yields the best estimate according to some criterion. We call these methods multiple oriented filters since each configuration is usually a rotated and shifted version of another. Multiple oriented filters work ...

Thresholding is a popular method of image segmentation. Many thresholding methods utilize only the gray level information of pixels in the image, which may lead to poor segmentation performance because the spatial correlation information between pixels is ignored. To improve the performance of thresolding methods, a novel two-dimensional histogram—called gray level-local variance (GLLV) histogr...

purpose : to evaluate orbital blood flow velocities and optic nerve diameter with doppler and gray-scale sonography in patients with acute unilateral optic neuritis (on) methods : orbital doppler and gray-scale sonography was performed in 46 eyes of 23 patients aged 19-47 with acute unilateral on. on was diagnosed by an ophthalmologist on the basis of clinical presentation, presence of decrease...

BACKGROUND AND PURPOSE After short periods of ischemia, commonly used staining methods yield only moderate differences in optical contrast between normal and damaged brain tissue when gray-scale images are used for computer-assisted image analysis. We describe a high-contrast silver infarct staining (SIS) method that allows an early delineation of ischemic tissue as soon as 2 hours after middle...

This paper presents the latest developments of the deterministic Macroscopic Cellular Automata model SCIARA for simulating lava flows. A Bingham-like rheology has been introduced for the first time as part of the Minimization Algorithm of the Differences, which is applied for computing lava outflows from the generic cell towards its neighbours. The hexagonal cellular space adopted in the previo...

Diagnostic techniques in cardiology require complex image analysis of single images and image sequences obtained by a variety of medical imaging modalities such as ECG-gated MR, CT, and ultrasound. Cardiac motion estimation provides useful information about cardiac function. In this work, we present a novel brightness-based algorithm for computation of optical flow. The advantage of brightness-...

In this paper, we present a video based smoke detection algorithm based on TVL1 optical flow estimation. The main part of the algorithm is an accumulating system for motion angles and upward motion speed of the flow field. We optimized the usage of TVL1 flow estimation for the detection of smoke with very low smoke density. Therefore, we use adapted flow parameters and estimate the flow field o...

In this study, three-dimensional simulations are presented for laminar forced convection flow of a radiating gas over a backward-facing step in rectangular duct. The fluid is treated as a gray, absorbing, emitting and scattering medium. The three-dimensional Cartesian coordinate system is used to solve the governing equations which are conservations of mass, momentum and energy. These equations...