Click-event detection device

摘要

There is provided a click-event detection device including a light source, a light control unit, an image sensor and a processing unit. The light control unit is configured to control the light source to illuminate a finger. The image sensor receives reflected light from the finger to accordingly output a plurality of bright image frames and dark image frames. The processing unit is configured to calculate a differential image characteristic between the bright image frames and the dark image frames, to determine a plurality of operating states according to the differential image characteristic, to count a residence time at each of the operating states, and to identify a click-event according to the operating states and the residence time.

主权项

1. A click-event detection device, configured to detect a click-event of a finger, the click-event detection device comprising:
a light source configured to illuminate the finger; a light control unit configured to control the light source to illuminate with a first brightness value and a second brightness value; an image sensor configured to receive reflected light from the finger at a sampling frequency to output bright image frames corresponding to the first brightness value and to output dark image frames corresponding to the second brightness value; and a processing unit configured to calculate a plurality of differential image characteristics according to the bright image frames and the dark image frames,
wherein the processing unit is configured to identify a single-click when following two conditions are satisfied sequentially: (1) a first variation of the differential image characteristics is larger than a first varying threshold within a first time interval; and (2) a second variation of the differential image characteristics is smaller than or equal to a second varying threshold within a second time interval, andwherein the processing unit is configured to identify a double-click when following four conditions are satisfied sequentially: (1) the first variation of the differential image characteristics is larger than the first varying threshold within the first time interval; (2) the second variation of the differential image characteristics is smaller than or equal to the second varying threshold within the second time interval; (3) a third variation of the differential image characteristics is larger than the first varying threshold within a third time interval; and (4) a fourth variation of the differential image characteristics is smaller than or equal to the second varying threshold within a fourth time interval.