The paper presents a method to uniquely determine the three-dimensional motion parameters of a rigid object with curved surfaces from two time-sequential views, using only seven point correspondences. The authors introduce a set of "essential parameters" that uniquely determine the motion parameters up to a scale factor for translations. These essential parameters can be estimated by solving a set of eight linear equations derived from the correspondences of eight image points. The actual motion parameters are then determined by computing the singular value decomposition (SVD) of a 3x3 matrix containing these essential parameters, without the need to solve any nonlinear equations. The paper also discusses the conditions under which the solution is unique, such as when the observed points do not lie on two planes with one plane containing the origin or on a cone containing the origin.The paper presents a method to uniquely determine the three-dimensional motion parameters of a rigid object with curved surfaces from two time-sequential views, using only seven point correspondences. The authors introduce a set of "essential parameters" that uniquely determine the motion parameters up to a scale factor for translations. These essential parameters can be estimated by solving a set of eight linear equations derived from the correspondences of eight image points. The actual motion parameters are then determined by computing the singular value decomposition (SVD) of a 3x3 matrix containing these essential parameters, without the need to solve any nonlinear equations. The paper also discusses the conditions under which the solution is unique, such as when the observed points do not lie on two planes with one plane containing the origin or on a cone containing the origin.