Resumen
The article reports that tangible user interfaces (TUIs) incorporate physical objects as sensors and effectors that, when manipulated, modify computational behavior. To enable the construction of TUIs, systems distinguish and identify physical objects, determine their location, orientation, or other aspects of their physical state, support annotations on them, and associate them with different computational states. To do this, TUIs use technologies such as radio emitters, bar codes, or computer vision. The first tangible paper system, the DigitalDesk, incorporates paper via computer vision. The DigitalDesk could copy and paste printed text or numbers from paper into digital documents, enabling the user to manipulate the information electronically. The article also describes that with flexible multimodal interfaces users can take advantage of more than one of their natural communication modes during human-computer interaction, selecting the best mode or combination of modes that suit their situation and task.