Search results for "Principal point"
showing 4 items of 4 documents
A New Set of Quartic Trivariate Polynomial Equations for Stratified Camera Self-calibration under Zero-Skew and Constant Parameters Assumptions
2012
This paper deals with the problem of self-calibrating a moving camera with constant parameters. We propose a new set of quartic trivariate polynomial equations in the unknown coordinates of the plane at infinity derived under the no-skew assumption. Our new equations allow to further enforce the constancy of the principal point across all images while retrieving the plane at infinity. Six such polynomials, four of which are independent, are obtained for each triplet of images. The proposed equations can be solved along with the so-called modulus constraints and allow to improve the performance of existing methods.
Self-calibration of a PTZ Camera Using New LMI Constraints
2013
In this paper, we propose a very reliable and flexible method for self-calibrating rotating and zooming cameras - generally referred to as PTZ (Pan-Tilt-Zoom) cameras. The proposed method employs a Linear Matrix Inequality (LMI) resolution approach and allows extra tunable constraints on the intrinsic parameters to be taken into account during the process of estimating these parameters. Furthermore, the considered constraints are simultaneously enforced in all views rather than in a single reference view. The results of our experiments show that the proposed approach allows for significant improvement in terms of accuracy and robustness when compared against state of the art methods.
Resistance to clarithromycin and genotypes in Helicobacter pylori strains isolated in Sicily
2015
The resistance of Helicobacter pylori strains to clarithromycin is increasing in several developed countries and their association with a genetic pattern circulation has been variously explained as related to different geographical areas. In this study we have reported: the prevalence of the resistance of H. pylori, isolated in Sicily, to clarithromycin; the principal point of mutation associated with this resistance; and the more frequent association between resistance to clarithromycin and cagA, the EPIYA motif, and the vacA and oipA genes. Resistance to clarithromycin was detected in 25 % of cases, the main genetic mutation involved being A2143G. The cagA gene was present in 48 % of case…
The effect of personal involvement on the decision to buy store brands
2002
Store brands are appearing in an ever‐increasing number of categories and their acceptance by consumers is unquestionable. The purpose of this paper is to model the decision process involved in a purchase which the consumer goes through when choosing store brands over national brands. The model provided allows us to explain why the same consumer may choose a store brand in one product category and not in another. We have taken personal product involvement as the principal point of reference.