1. A method, comprising: detecting an image of one or more hands against a 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 by at least a part of one of the hand areas is defined as an independent area; associating a control parameter for manipulating a displayed image on a user interface with each counted independent area; 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.