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Preliminary kinematic model for the Gulf of Suez, Egypt, using geodetic and seismic observations

Saleh S., Hamdy A.M., Tealeb A.

Acta Geophysica Polonica

2005

Vol. 53, nr 1

87-102

The Suez Rift has been re-evaluated from recent three GPS measurements and earthquake data analysis. The GPS analysis reveals local principal strains along the southern part taking a NE-SW contraction. However, it takes a NNE-SSW direction in the northern part with tensile principal strains. Throughout the central part of the gulf, the principal strains tend to be in the ENE-WSW direction due to right lateral movement. The Gulf of Suez can be divided into three seismic provinces. Generally, earthquake activity markedly increases from north to south. Slip vector analyses were carried out for 23 available earthquake focal mechanisms along the Gulf of Suez. In the southern part, the slip vector is generally trending ENE-WSW and NE-SW. However, in the northern part the direction of the slip vector varies from NNE-SSW to NE-SW. The central region represents a seismic gap between the northern and southern provinces with slip vectors of a NE-SW trend. Contrary to the previous tectonic studies, compressional field has been detected from GPS analysis and focal mechanism solutions of a few earthquakes. This raises from the highly complicated motion of Sinai subplate relative to African plate to the postseismic viscoelastic relaxation of the ductile shallow layers after the occurrence of November 1995 earthquake.

Segmentation based on homomorphic filtering and improved seeded region growing for mobile robots tracking in image sequences

Kasinski A. J., Hamdy A. M.

Machine Graphics and Vision

2001

Vol. 10, No. 4

447-466

In this paper, we present a method for extracting of mobile robots in a sequence of noisy frames, assuming a complex background composed of textured floor, illuminated unvenly. A homomorphic filter if used, as a preprocessor, to enhance the acquired frames by eliminating the illumination component and emphasizing the reflectance component of the image function. To speed up preprocessing of each frame, filtering is only applied to the pixels belonging to the regions of interest (ROI). In all the tested cases, homomorphic--filtering led to better results than those obtained without preprocessing. The segmentation process has been based on seeded region growing procedure for reconstructing the shape of the mobil robot. We proposed automatic seed points selection in the binarized difference image, and use an adaptive threshold. This use eliminates or at least considerably reduces false negative detections, and reduces sensitivity of aggregation results to the selected seed points as compared to the classical seeded region growing procedure. Additionally, by imposing a condition of strong connectivityu bettween a seed point and its neighborhood, aggregation of undesired pixels efficiently eliminates false positive detections. Implementation of segmentation and tracking can be run in real time. High tracking accuracy has been obtained through out all the frames in a test sequence.