A method for performing auto-exposure (AE) control in a depth sensing system includes: capturing a first reference image and a second reference image of a scene based on different illumination conditions; calculating a plurality of first block means with respect to first blocks of the first reference frame and calculating a plurality of second block means with respect to second blocks of the second reference frame; calculating a plurality of block mean differences according to the first block means and the second block means; determining a plurality of first region of interest (ROI) blocks from the first blocks and a plurality of a second ROI blocks from the second blocks; and performing an AE control over the depth sensing system according to blocks means of the first ROI blocks and blocks means of the second ROI blocks.