1. A method for determining HRTF, comprising: obtaining a plurality of reference images of different respective ears, one or more of the reference images associated with a corresponding pre-determined HRTF information; obtaining information regarding an input image that includes an image of an ear of a subject; comparing the information regarding the input image with information regarding the reference images using a processor; and selecting one of the pre-determined HRTF information based at least in part on a result of the act of comparing.