Input device, method of controlling input device, and program

An input device that enters information according to a proximity state of an object approaching thereto, the input device comprising:

• a detecting unit configured to generate a detection signal that changes according to a degree of proximity of the approaching object;
• a deciding unit configured to decide whether a change in the detection signal due to the proximity of the approaching object has occurred based on a series of detection values of the detection signal, according to decision criteria;
• and
• a reference value updating unit configured to update a reference value for the detection signal, if the deciding unit makes a decision that a change in the detection signal due to the proximity of the approaching object has not occurred, the reference value indicating a value of the detection signal in a state in which no object is approaching, according to the series of detection values generated in the detecting unit,
• wherein the deciding unit is further configured to change at least one of the decision criteria, such that the greater a difference between the reference value and the detection value of the detection signal is, the more likely the deciding unit is to make a decision that the change in the detection signal due to the proximity of the approaching object has occurred, the difference between the reference value and the detection value of the signal indicating the degree of proximity of the approaching object, whereby the higher the degree of the proximity of the approaching object is, the less likely the reference value is updated.