Elementals Pollution Status of a University Dumpsite Soil in Ile-Ife, Nigeria

This study explored the concentrations of various elements in Obafemi Awolowo University dumpsite using Inductively Couple Plasma Optical Emission Spectroscopy. A total of fifty soil samples were collected each month for a duration of eight months. Each month, five soil samples each were randomly collected from different spot at 0-15 cm and 15-30 cm depths from each of the four equidistant circular points and at the centre of the dumpsite in well pre-treated sealed polythene bags. The values obtained revealed that Fe, Mn, Ti, Ba and Al were below the background values while Ni, Co, Zn, Cu, Be, Al, Se, Si, As, Zr and Y were above the background values. Geo-accumulation study indicated that the dumpsite was practically unpolluted with, Fe, Mn, Ni, Ti, Ba, Al, Si , U and Y; highly polluted with As and Cu; Co, Zn and Zr ranged from unpolluted to moderately polluted; Se ranged from unpolluted to highly polluted; while Be ranged from moderately polluted to highly polluted. Mean levels of the potentially toxic metals in the dumpsite and its vicinity were higher in the top soil than sub-soil; and metal concentrations in wet season were higher than dry season.

Camera calibration method based on Pascal’s theorem

As one of the classical theories of projective geometry, Pascal’s theorem is closely related to the conic, which is the image of a circle. A circle is the geometric element typically used as a template for camera calibration methods. In this work, we propose a calibration method based on Pascal’s theorem and its inference, in which a circle is used as the calibration template. The proposed calibration method can be applied to solve the image of the circular points via the Newton iteration method. The intrinsic parameters of the camera can then be determined based on the constraints of the images of the circular points and the image of the absolute conic. The results of simulations and experiments conducted verify the validity and feasibility of the proposed calibration method.

Paracatadioptric camera calibration based on properties of polar line of infinity point with respect to circle and line

Two linear calibration methods based on space-line projection properties for a paracatadioptric camera are presented. Considering the central catadioptric system, a straight line is projected into a circle on the viewing spherical surface for the first projection. The tangent lines in a group at antipode point pairs with respect to the circle are parallel, with the infinity point being the intersection point; therefore, the infinity line can be obtained from two groups of antipode point pairs. Further, the direction of the polar line of an infinity point with respect to the circle is orthogonal to the direction of its infinity point. Hence, on the imaging plane, images of the circular points or orthogonal vanishing points are used to determine the intrinsic parameters. On the basis of the properties of the antipodal point pairs and a least-squares fitting, a corresponding optimization algorithm for line image fitting is proposed. Experimental results demonstrate the robustness of the two calibration methods, that is, for images of the circular points and orthogonal vanishing points.