An apparatus for structured stereo, comprising: a first subsystem arranged to include: a first emitter; and first and second sensors (204,206), wherein the first and second sensors are asymmetrically placed with respect to the first emitter, wherein the first emitter is arranged intermediate the first and second sensors, and an optical distance between the first emitter and the first sensor is shorter than an optical distance between the first emitter and the second sensor; and wherein the first emitter and the first sensor are configured to generate a sparse depth map of low accuracy of an area, and the second sensor is configured to obtain an image of the area, the image being used to refine the sparse depth map to enable generation of a high accuracy depth map having a higher accuracy than the sparse depth map; a second subsystem arranged to include: a second emitter; and third and fourth sensors (302,304), wherein the third and fourth sensors are asymmetrically placed with respect to the second emitter, wherein an optical distance between the third and fourth sensors is shorter than respective optical distances between the third sensor and the second emitter, and the fourth sensor and the second emitter; and wherein the third and fourth sensors are configured to generate a dense low accuracy depth map of the area, and the second emitter is configured to be matched with the fourth sensor through structured light to provide refinement for at least some pixels of the dense low accuracy depth map; and a processor configured to calculate a dense high accuracy depth map of the area from the high accuracy depth map and the dense low accuracy depth map. a first subsystem arranged to include: a first emitter; and first and second sensors (204,206), wherein the first and second sensors are asymmetrically placed with respect to the first emitter, wherein the first emitter is arranged intermediate the first and second sensors, and an optical distance between the first emitter and the first sensor is shorter than an optical distance between the first emitter and the second sensor; and wherein the first emitter and the first sensor are configured to generate a sparse depth map of low accuracy of an area, and the second sensor is configured to obtain an image of the area, the image being used to refine the sparse depth map to enable generation of a high accuracy depth map having a higher accuracy than the sparse depth map; a first emitter; and first and second sensors (204,206), wherein the first and second sensors are asymmetrically placed with respect to the first emitter, wherein the first emitter is arranged intermediate the first and second sensors, and an optical distance between the first emitter and the first sensor is shorter than an optical distance between the first emitter and the second sensor; and wherein the first emitter and the first sensor are configured to generate a sparse depth map of low accuracy of an area, and the second sensor is configured to obtain an image of the area, the image being used to refine the sparse depth map to enable generation of a high accuracy depth map having a higher accuracy than the sparse depth map; a second subsystem arranged to include: a second emitter; and third and fourth sensors (302,304), wherein the third and fourth sensors are asymmetrically placed with respect to the second emitter, wherein an optical distance between the third and fourth sensors is shorter than respective optical distances between the third sensor and the second emitter, and the fourth sensor and the second emitter; and wherein the third and fourth sensors are configured to generate a dense low accuracy depth map of the area, and the second emitter is configured to be matched with the fourth sensor through structured light to provide refinement for at least some pixels of the dense low accuracy depth map; and a second emitter; and third and fourth sensors (302,304), wherein the third and fourth sensors are asymmetrically placed with respect to the second emitter, wherein an optical distance between the third and fourth sensors is shorter than respective optical distances between the third sensor and the second emitter, and the fourth sensor and the second emitter; and wherein the third and fourth sensors are configured to generate a dense low accuracy depth map of the area, and the second emitter is configured to be matched with the fourth sensor through structured light to provide refinement for at least some pixels of the dense low accuracy depth map; and a processor configured to calculate a dense high accuracy depth map of the area from the high accuracy depth map and the dense low accuracy depth map.