See video for full details.
Writing software and configuring it for different types of hardware is always a challenge. Sometimes one of the key challenging components is also considering the variety and diversity of the end user. For an example, see the video demonstration below of HP's new face tracking webcam:
An HP representative commented in the Voodoo Blog, "Some of you may have seen or heard of a YouTube video in which the facial-tracking software didn’t work for a customer. We thank Desi, and the people who have seen and commented on his video, for bringing this subject to our attention."
The response continued, "We are working with our partners to learn more. The technology we use is built on standard algorithms that measure the difference in intensity of contrast between the eyes and the upper cheek and nose. We believe that the camera might have difficulty 'seeing' contrast in conditions where there is insufficient foreground lighting."