A method for disparity cost computation for a stereoscopic image is provided that includes computing path matching costs for external paths of at least some boundary pixels of a tile of a base image of the stereoscopic image, wherein a boundary pixel is a pixel at a boundary between the tile and a neighboring tile in the base image, storing the path matching costs for the external paths, computing path matching costs for pixels in the tile, wherein the stored path matching costs for the external paths of the boundary pixels are used in computing some of the path matching costs of some of the pixels in the tile, and computing aggregated disparity costs for the pixels in the tile, wherein the path matching costs computed for each pixel are used to compute the aggregated disparity costs for the pixel.