1. A method for identifying and labeling cluster pixels in a frame of image data for optical navigation, said method comprising: determining whether a current pixel of said frame of image data is a cluster pixel; determining whether any of neighboring pixels of said current pixel is labeled as belonging to at least one existing cluster; labeling said current pixel as belonging to a new cluster if none of said neighboring pixels of said current pixel is labeled as belonging to said at least one existing cluster; and labeling said current pixel as belonging to a particular cluster of said at least one existing cluster if at least one of said neighboring pixels of said current pixel is labeled as belonging to said at least one existing cluster.