CONvolutional Virtual Electric Field force for Active Contours

an effective external force for active contours, extended from VEF model

This program is based on Chenyang Xu's package.
My contribution is that I have proposed 2 effective external forces for active cotnours, working as an alternative to the GVF force, i.e., CONVEF(CONvolutional Virtual Electric Field),and GVC(Gradient vector convolution). the CONVEF is an extension of the VEF field, and is closely related to the VFC model, but the CONVEF is much more effective. See the following papers for details:
1. Yuanquan Wang, and Yunde Jia, Convolutional virtual electric field
external force for active contours, in Proc. Asia Conf. Computer Vision, 2009.
2. Wang Y, Jia Y (2008) External force for active contours: gradient vector convolution. In: PRICAI, (2008) trends in artificial intelligence, pp 466–472

Copyright: Yuanquan Wang, the core code is first build during 06/05 -09/05 and this concise test code for CONVEF is arranged and commented on 2013/12/30 the GVC code is very simple and will be released in near future, since we have a more extension of the GVC and I am too busy to prepare a paper. if any one is interested in this work, we can collaborate on this paper, corresponding author is enough for me! to note, the GVC model has been cited by the Nature Methods Journal.