Tomographically reconstructing a 3D image object corresponding to a data set includes reconstructing a first reconstructed object from the data set, receiving a smoothing map, smoothing the first reconstructed object based on the smoothing map thereby creating a first smoothed object, and outputting the first smoothed object as the 3D image object. Smoothing a first object thereby creating a smoothed object having a smoothed value associated to each object point in object space includes receiving the first object, determining, in a series of steps, single-kernel-smoothed objects, wherein each iteration step is associated with a kernel function and includes, determining a start object based on the first object, and smoothing the start object using the kernel function of the iteration step, thereby creating the single-kernel-smoothed object having single-kernel-smoothed values associated to each object point, and constructing the smoothed object from the single-kernel-smoothed values.