1. A method for initializing depth estimates in an iterative process for stereoscopic ranging, the method comprising: projecting a first depth estimate for each one of a plurality of valid pixels in an image, the image having an implicit camera origin; generating a 3D representation of the plurality of valid pixels using the first depth estimate; relocating the implicit camera origin; reprojecting the 3D representation of the plurality of valid pixels to the relocated implicit camera origin; using Z-buffering to render a second depth estimate for each one of the plurality of valid pixels according to the relocated implicit camera origin; and using the second depth estimate for each of the plurality of valid pixels as an initial value in a subsequent iteration of a process for stereoscopic ranging.