Abstract: Considering that 3D medical image registration has the problems of huge data,high computational complexity and low registration precision,this paper proposed a registration method based on Clifford algebra geometric invariants to realize 3D medical image registration of skull part for human,proposed Clifford algebra geometric invariants and Clifford algebra equation formulas needed by registration,constructed Clifford geometric rotation operator which is fit for rotation for the geometric reference axis,established the rotation composite operator using the corresponding Clifford geometric invariants obtained by the maximum and minimum values．To realize registration,geometric transformation was made for the floating image data．Two famous 3D medical data were tested in registration experiments．The experimental result indicates that this method has the advantages of simple calculation method,intuitive geometric meaning,high registration precision,high execution efficiency,and also not easily falls into the local extreme value in the registration process.

Key words: Clifford algebra,Geometrical invariance,3D Medical image registration,Geometric rotation operator