A correspondence between a source image and a reference image is determined. A generative model corresponds to a prior probability distribution of deformation fields, each deformation field corresponding to a respective coordinate transformation. A conditional model generates a style transfer probability distribution of reference images, given a source image and a deformation field. The first image data is the source image, and the second image data is the reference image. An initial first deformation field is determined. An update process is iteratively performed until convergence to update the first deformation field, to generate a converged deformation field representing the correspondence between the source image and the reference image. The update process includes: determining a change in one or more characteristics of the first deformation field to increase a posterior probability density associated with the first deformation field, given the source image and reference image; and changing the one or more characteristics in accordance with the determined change.