Input terminal device and operation input method

An input system for receiving an operation of a user through a position input object, comprising:

• a three-dimensional position detector configured to non-contactedly detect a three-dimensional position of the position input object;
• a display configured to present a displayed indicator corresponding to at least a lateral component of the detected three-dimensional position;
• and
• an operation processing controller configured to control execution of one or more operation processes in accordance with a plurality of control states,
• wherein the operation processing controller is configured to:
• determine a control state based on a characteristic of the detected three-dimensional position of the position input object, the characteristic including at least a temporal characteristic of the detected three-dimensional position, the temporal characteristic including a length of time during which the detected three-dimensional position of the position input object is maintained within a predetermined spatial range, while the displayed indicator is moved in accordance with movement of the position input object, and
• switch between the plurality of control states according to the determined control state.