1. An input device comprising: a first light emitter for emitting a first light of a first wavelength; a second light emitter for emitting a second light of a second wavelength; a first finger component for being worn on a finger, configured to dedicatedly reflect the first light; a second finger component for being worn on a finger, configured to dedicatedly reflect the second light; a first image capture module sensible to the first light reflected by the first finger component but insensible to the second light, and configured to capture images of the first finger component; a second image capture module sensible to the second light reflected by the second finger component but insensible to the first light, and configured to capture images of the second finger component; and an image recognition module configured to determine movement traces of the first and second finger components based on the images of the first and second finger components; wherein the first and second finger components are separated from and move independently in relation to the first and second light emitters.