1. A method, comprising: detecting an image of one or more hands against a substantially stationary background via a camera; segmenting the image into hand areas and background areas; at intervals, counting a number of independent areas of the background, wherein each part of the background that is visually independent from other parts of the background is defined as an independent area, each of the independent areas being visually separated from the other parts of the background by at least a part of the hand areas; associating a control parameter for manipulating a displayed image on a user interface with a centroid of each counted independent area; and changing the displayed image via the control parameter in relation to each change in a shape and/or a position of the independent area associated with the control parameter.