1. A method of registering a first volume with a second and different second volume, the method comprising: generating by a processor three two-dimensional (2D) signatures for the first volume where each corresponds to a different one of three orthogonal directions; generating by the processor three 2D signatures for the second volume where each corresponds to a different one of the three orthogonal directions; registering by the processor the 2D signatures of the first volume with the 2D signatures of the second volume for each same orthogonal direction to generate three transformations; and registering by the processor the first volume with the second volume using the three generated transformations, wherein each pixel position of each 2D signature includes a minimum voxel intensity and maximum voxel intensity of a ray intersecting the corresponding 3D volume through the corresponding orthogonal direction and each 2D signature further includes rotation information and translation information of the corresponding 3D volume.