In the viewsight of anthropology,the development of vocational abilities is an aspect of social practice,the development process of vocational abilities is that the trainees understand and participate in the continuous changing social practice by the mode of "legitimate peripheral participation" in the community of practice,which emphasize that the developm.

From the perspective of anthropology, situational learning theory has its core characteristics and elements, practice community is the carrier of knowledge, learning is achieved through legitimate peripheral participation, the whole learning process is understood as cultural absorption and fusion, and ultimately achieve the transformation of identity in community.

We provide a new vision for teachers\' practical knowledge management by explaining legitimate peripheral participations\' concept and its nature,and make reasonable analysis of internal needs and external constitute.

It possesses good edge-preserving property.

In the method,the automatic identification of feature area is fulfilled based on the edge attribute,and the sub-pixel center location is accomplished with the least-square approach.

Different from other common segment method,the proposed method refers to color rarity and local edge proper considering the characteristics of soccer video images,that most non-object regions are roughly single green.