Abstract: Aiming at the realistic three-dimensional model of soybean leaf based on images,considering the impact of leaf area index(LAI)on soybean production,a method for three- dimensional modeling of leaf on the constraint of leaf area was proposed．Firstly,the feature points and leaf area were extracted form the image,and then the feature points were interpolated to get a bi-cubic uniform B-spline surface.The mesh was deformed according to the curl of leaf edge and the curly leaf model was constructed.Lastly,the maximum illumination area of each model separately was calculated to chose the optimal model．The experimental results show that the method can construct the realistic three-dimensional model of soybean leaf．The method has certain biological significance and application value.

Key words: Feature points,Curve fitting,B-spline surface,Area constraint,Three-dimensional modeling