1. A system for generating a depth map for an object in a three-dimensional (3D) scene, comprising: an image capture sensor configured to capture a plurality of images of the object at a plurality of different focal planes; and a processor configured to: calculate a plurality of variance values for a plurality of image locations for each image captured by the image capture sensor; determine a peak variance value for the plurality of image locations based on the calculated variance values associated with the same image location for each of the plurality of images of the object at the plurality of different focal planes; and generate the depth map for the object based on the determined peak variance value for each image location and the plurality of different focal planes.