1. A method of extracting a target, the method comprising: extracting a background image from an input image; modeling brightness values of the input image and the background image based on a Gaussian distribution to generate an input image modeling result and a background image modeling result; calculating likelihood ratios for determining whether a pixel in the input image corresponds to a target based on a correlation between the input image modeling result and the background image modeling result and target templates having different sizes; determining a location of the target based on the calculated likelihood ratios; and outputting the determined location of the target.