18. The system of claim 15 , wherein the at least one image feature cue comprises hue, saturation, value, focus, texture, or a combination thereof.
18. The system of claim 15 , wherein the at least one image feature cue comprises hue, saturation, value, focus, texture, or a combination thereof. 20. The system of claim 18 , wherein the focus is computed as a ratio of high pass energy to low pass energy.