描述蝴蝶兰图像外轮廓信息的对称8链码编码算法

Symmetrical 8 Chain Code Encoding Algorithm to Describe Outer Contour Information of Phalaenopsis Amabilis Images

外轮廓信息是评价蝴蝶兰生长态势的重要特征参数,主要通过轮廓提取和链码编码两个步骤获得。蝴蝶兰图像的边缘轮廓最适合利用数学形态学算法提取,但所得轮廓并非单像素宽度,而利用传统8链码算法编码会错误地表达其外轮廓信息,因此结合轮廓特点重新定义了起始链码方向,提出了对称8链码编码算法。在编码过程中,该算法能够通过变换点判断出当前轮廓走向,从而自适应地选择起始链码方向。验证性实验证明,该算法能够准确描述蝴蝶兰图像的外轮廓信息,保证外轮廓信息较低的误判率;通用性实验证明,该算法同样适用于其他已较好提取出目标的封闭图像。

One important feature parameter to judge the growing situation of phalaenopsis amabilis is outer contour in- formation, which is obtained by contour extracting and chain code encoding. Mathematical morphological algorithm is more suitable to extract phalaenopsis amabilis edge contour, however,its edge contour is no-single pixel width,and tra- ditional 8 chain code algorithm will wrongly express the outer contour information. Combining contour direction fea- ture, we defined starting chain code direction and proposed symmetrical 8 chain code algorithm. During the encoding process, this algorithm can judge current contour direction through change points, and then select the starting chain code direction adaptively. Verification experiments show that this algorithm can well. describe the outer contour information with low misjudgement rate, and general experiments prove that this algorithm is also suitable for other enclosed images which have extracted target well.