A device for detecting a plant includes a two-dimensional camera for detecting a two-dimensional image of a plant leaf having a high two-dimensional resolution, and a three-dimensional camera for detecting a three-dimensional image of the plant leaf having a high three-dimensional resolution. The two-dimensional camera is a conventional high-resolution color camera, for example, and the three-dimensional camera is a TOF camera, for example. A processor for merging the two-dimensional image and the three-dimensional image creates a three-dimensional result representation having a higher resolution than the three-dimensional image of the 3D camera, which may include, among other things, the border of a leaf. The three-dimensional result representation serves to characterize a plant leaf, such as to calculate the surface area of the leaf, the alignment of the leaf, or serves to identify the leaf.