[Objectives]The paper aims to improve the segmentation accuracy of wheat canopy image under the low contrast,reflections,shadows,light and shade caused by uneven illumination,complex background in the field. [Methods]This paper designed a K-means clustering segmentation algorithm based on alpha angle model of L*a*b* color space after adaptive image was enhanced and combined with pulse coupled neural network(PCNN) and homomorphic filtering. Firstly,convert the wheat canopy image from RGB to HSI color space,a...