In order to enhance the smoothness of the measurement curve and accelerate the registration speed in medical image registration,the confidence region integrating deterministic information and stochastic information(DSCR) is defined,where the deterministic information is the intensity probability distribution in images and the stochastic information is the stochastic intensity information at non-grid position.And then a new nearest neighbor interpolation method based on DSCR is proposed,which is abbreviated as DSCRNN.The values of normalized mutual information(NMI) are deterministic and accurate at any grid translation position when the DSCRNN interpolator is used.The measures′ curves,interpolation time,noise immunity and convergence are compared by applying 8 interpolation methods to the rigid registration of brain images.The results of tests show that the new DSCRNN interpolator outperforms the other interpolators in convergence performance and noise immunity without compromising interpolation speed.