68 Research on the Barcode Positioning and Correction Method Based on Improved Convex Hull Algorithm for Mobile Phone Available to Purchase

It is inevitable that barcode images captured by mobile phone camera have some extent of tilting and distortion. In traditional method, the Hough Transform method is adopted to detect the L-shape in the barcode image of Data Matrix. However, with huge complexity and large storage space, it is not suitable for application on the mobile phone. In this paper, under Symbian OS in Nokia, an improved convex hull algorithm is adopted to exclude some invalid convex hull vertices through angle, length calculation filters. Then a fake quadrilateral is created to fit Data Matrix image contour. This approach can both shorten calculation time and ensure accurate positioning. It is suitable for mobile phone application. At the end of this paper, both the traditional method and the improved approach are tested on Nokia N73 for the comparison of the efficiency and effectiveness.