1. A robot cleaner, comprising: a body; a cleaning device operably coupled in the body and configured to draw dust from a cleaning region into the body; an optical pattern sensor provided on a front surface of the body and configured to irradiate an optical pattern and generate a corresponding pattern image; and a controller configured to recognize an obstacle based on the pattern image generated by the optical pattern sensor, wherein the optical pattern sensor includes: an optical source module configured to irradiate one or more optical patterns outward from a front side of the body; a camera module configured to capture the pattern image of a region irradiated by the one or more optical patterns; and a filter connected to a front end of the optical source module, and configured to pass at least a portion of the one or more optical patterns irradiated from the optical source module, wherein the portion of the one or more optical patterns is included in a prescribed frequency band, wherein the optical source module is configured to irradiate an asymmetric cross-shaped optical pattern having a horizontal pattern and a vertical pattern, wherein a length of the horizontal pattern is greater than a length of the vertical pattern, wherein the horizontal pattern and the vertical pattern are generated by the same optical source module and irradiated from a single point on a surface of the optical source module, wherein the controller includes an obstacle recognition module configured to process the pattern image to recognize the obstacle, and wherein the obstacle recognition module recognizes a height of the obstacle using the vertical pattern and the horizontal pattern of the pattern image, determines a position of the horizontal pattern from the pattern image when no obstacle is present, calculates a moving distance of the position of the horizontal pattern when the obstacle is present, and recognizes the height of the obstacle by the moving distance.