1. A method, comprising: registering a new image volume with a composed image volume, wherein the new image volume and the composed image volume overlap each other in an overlap region, the composed image volume includes at least two image volumes that overlap each other, and each voxel in the composed image volume includes a weight; determining a deformation between the new image volume and the composed image volume; updating the weights of the voxels in the composed image volume that are overlapped by the new image volume; performing an alpha morphing on the overlap region using the updated weights and the deformation; obtaining a blend region of the overlap region by performing an alpha blending using results of the alpha morphing and the updated weights; and incorporating the blend region into the composed image volume to obtain a new composed image volume, wherein the weight of a voxel in a single image volume is based on its distance from an edge of the single image volume, wherein the weight of a voxel in the composed image volume, where this voxel is included in a region of the composed image volume where the at least two image volumes overlap, is equal to a sum of the weights of the corresponding voxels from the at least two image volumes, wherein updating the weights of the voxels in the composed image volume that are overlapped by the new image volume comprises: for each voxel of the composed image volume overlapped by the new image volume, adding the weight of the corresponding voxel from the new image volume to the weight of that voxel in the composed image volume.