Although mobile phones have become increasingly
powerful in terms of performance, we still wish to reduce the
processing costs as much as possible to ensure the system
runs fast enough to be seamlessly interactive. Considering
this, the size of input images (640 x 960 pixels) is reduced
before the color-based recognition and tracking of a finger is
executed. Actually, we merge 4x4 pixels into one whose
color is given by the average of those 16 pixel colors.
In
addition, we assume a finger cap is used to reduce the
influence of lighting conditions (Fig. 5).