Abstract: An improved LBF (ILBF) model which is applied to image segmentation was proposed， which constructed a new energy function. The local and global information were described by LBF model with different scale parameters. And local entropy notion was applied to ILBF model and weight parameter ω in energy function could also be got automatically. The LBF model with a larger scale parameter had both global and local characteristics， and it was used instead of CV model in LGIF model. The ILBF model overcame the shortcoming of LGIF model in which the weight parameter was calculated by artificial. In order to avoid too much useless cyclic iterations， a new stop criterion was presented too.

Key words: image segmentation, geometry active contour, LBF model, ILBF model, local entropy