In computer vision, scales are important when we carry out a scene analysis. Choosing different scales affect the result of the analysis. For example, if a face is relatively small in the scene, then the details including nose, eyes will be omitted. On the other hand, details on larger faces become relatively more salient.
I know both Gaussian Blur with different sigmas and Down Sampling on the image can generate different scales. Which is more reasonable on a cognitive sense?