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Boundary tracing of a binary digital region can be thought of as a segmentation technique that identifies the boundary pixels of the digital region. Boundary tracing is an important first step in the analysis of that region. Algorithms such as Square Tracing algorithm,Moore-Neighbor Tracing algorithm and the Theo Pavlidis’ algorithm have been used for boundary tracing.〔(Contour Tracing Algorithms )〕 With an abstract cell complex representation of a digital image the boundary point coordinates may be extracted from that digital image by following an algorithm created by (Dr Kovalevsky ) using modulo division and simple pixel lookups. A generic approach using vector algebra for tracing of a boundary can be found at.〔Vector Algebra Based Tracing of External and Internal Boundary of an Object in Binary Images, Journal of Advances in Engineering Science Volume 3 Issue 1, January - June 2010, PP 57-70 ()〕 An extension of boundary tracing for segmentation of traced boundary into open and closed sub-section is described at.〔Graph theory based segmentation of traced boundary into open and closed sub-sections, Computer Vision and Image Understanding, Volume 115, Issue 11, November 2011, Pages 1552–1558 ()〕 ==Algorithm== This algorithm assumes a single connected region within the binary image and begins with an exhaustive search to locate the first foreground pixel by iterating over the columns and rows of the image. // 2D Point data structure typedef struct P Point; // Example Image Data const int width = 6; const int height = 10; int()() image = , , , , , , , , }; // Exhaustive row-major order search for first foreground pixel Point startPoint; for ( int row = 0 ; row < height ; row++ ) } Once that pixel is located the algorithm may begin by tracing the cracks of the region in a counterclockwise fashion following one of four possible directions at each step. These directions are represented by a crack code sequence: 0 (East), 1 (South), 2 (West), 3 (North) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Boundary tracing」の詳細全文を読む スポンサード リンク
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