In order to better study plant black rot

the segmentation of black rot lesion image of cruciferous plant was carried out in this study. And the image fuzzy threshold method was used to fulfill the segmentation according to the characteristic of the lesions. First

due to the problem of automatic selection of window size for image thresholding by index of fuzziness

an adaptive window size selection method for image thresholding by index of fuzziness was put forward under a predetermined membership function and given the class numbers of image pixels.Then

image whose histogram possesses one mode or two modes with great disparity was difficult to be segmented using thresholding by index of fuzziness were studied

a histogram transformation method was presented. At last

the image could be segmented through the transformed histogram using the adaptive thresholding by index of fuzziness. The experiment results of lesion segmentation using the collected leaves show that the method proposed in this paper is of effective and robust.