1. A method performed by one or more processors, comprising: retrieving a set of images; selecting, based on the images retrieved, a reference template; generating an approximate representation of at least one image of the set of images to reduce a computational complexity of calculating optimal transportation plans for the at least one image and the reference template, wherein the computational complexity is reduced relative to a computational complexity of calculating optimal transportation plans with an image, the generating comprising: clustering the at least one image into regions; calculating an approximation error for each of the regions; and based on the approximation error, modifying one of the regions; calculating optimal transportation plans between the reference template and each of the images in the set that includes the at least one image with the modified one of the regions; calculating, using the optimal transportation plans, a linear optimal transportation metric between at least two images in the set; identifying, based on the linear optimal transportation metric, a correspondence between a first image in the set and a second image in the set; and generating data for one or more visualizations based on the identified correspondence between the first image in the set and the second image in the set.