Video-based handwriting input

Disclosed is a method and an apparatus, as well as a computer recording medium for handwriting input. The invention is implemented by capturing images including raw strokes with a digital camera and receiving writing sounds with a microphone, when a user writes on a writing surface with a stylus having a special mark (such as special color point or light point), said images and sounds are time-stamped; extracting images of raw stroke by comparing the captured images with the special mark on the stylus; and retrieving "effective strokes" from the raw strokes by utilizing the received writing sounds. Moreover, the invention discloses a low cost, wireless method and apparatus for handwriting input which enables an user to write on a paper without a touch sensor provided for a computer system (such as Notebook and PDA etc.) equipped with an embedded digital camera.