The widespread availability of portable computing power and inexpensive digital cameras are opening up new possibilities for retailers in some markets. One example is in optical shops

where a number of systems exist that facilitate eyeglasses selection. These systems are now more necessary as the market is saturated with an increasingly complex array of lenses

frames

coatings

tints

photochromic and polarizing treatments

etc. Research challenges encompass Computer Vision

Multimedia and Human-Computer Interaction. Cost factors are also of importance for widespread product acceptance. This paper describes a low-cost system that allows the user to visualize different glasses models in live video. The user can also move the glasses to adjust its position on the face. The system

which runs at 9.5 frames/s on general-purpose hardware

has a homeostatic module that keeps image parameters controlled. This is achieved by using a camera with motorized zoom

iris

white balance

etc. This feature can be specially useful in environments with changing illumination and shadows

like in an optical shop. The system also includes a face and eye detection module and a glasses management module.