1. A computerized method comprising: generating two two-dimensional scale space representations from two different pictures of a three dimensional spatial scene, wherein the three dimensional spatial scene comprises a plurality of objects at different distances, each of the two-dimensional scale space representations comprises a plurality of pictures, and each of the plurality of pictures included in the respective scale space representation has a resolution that is the same as a resolution of a different picture corresponding to one of the two-dimensional scale space representation; computing, with an imaging system, a relative blur between the two different pictures using the two two-dimensional scale space representations, wherein the computing the relative blur further includes matching, based on blur comparisons, each block from a first picture of the two pictures to a closest corresponding block in the two-dimensional scale space representation corresponding to the second picture of the two pictures; and computing a picture depth map based on the relative blur, wherein an entry in the picture depth map has a corresponding entry in a blur map and the picture depth map is subsequently used to determine values for the different distances of the plurality of objects.