Fig. 2
From: Comparison and extension of three methods for automated registration of multimodal plant images
Scheme of evaluation of image registration. a FLU images are prescaled to the height of VIS images in order to improve robustness of subsequent registration. b Registration of prescaled FLU and VIS images is performed to obtain the transformation matrix \(T_{ij}\) describing global image rotation, scaling and translation. Transformations ranging within the scope of admissible rotation, scaling and translation values are treated as a success; otherwise, registration is considered to have failed. c To assess accuracy of image registration, the resulting transformation is applied to manually segmented FLU/VIS images. d The accuracy of FLU/VIS image registration is measured as the overlap ratio (OR) between the area of the manually segmented VIS plant image that is covered by the registered FLU image and the total area of the manually segmented plant regions; see Eq. 2