The Face Detector

Roland Piquepaille writes "Almost all human faces have common characteristics, such as two eyes and one mouth. Still, some people, affected by face blindness, cannot recognize one face from another one. So it's understandable that face recognition is a major challenge for computer vision systems. In "Facing facts in computer recognition,", the Pittsburgh Post-Gazette reports that a team from Carnegie Mellon University's Robotics Institute has developed a very accurate software to find faces within images. By analyzing only 768 pixels, the system can detect 93 percent of the faces in a set of images while falsely identifying four objects as faces. The Face Detector Demo is available online and you can submit an image for analysis and receive the results by e-mail. The technology will be used for security purposes, but also by digital photography companies who want to automatically reduce "red eye" effects. You'll find more details and references in this overview."

Comments

Red eye

[Todd Fisher]

Source Kodak:

The "red-eye" phenomenon has been familiar to photographers since the introduction of synchronized flash picture-taking. It's caused by the reflection of light off the blood vessels of the retina of the subject's eyes. It occurs most often when the flash is located close to the picture-taking lens of the camera.

The red-eye effect tends to be more evident when the subject is young and has blue or gray eyes which reflect more light than darker eyes. Also, children have larger pupils and less pigmentation than adults' eyes and they transmit more light back to the camera lens.

Red-eye wasn't so common with older, bulkier cameras that had separate flash units. These units were attached to a handle or flash bracket several inches away from the lens, or the photographer could detach the flash and hold it away from the camera. With today's popular small cameras with built-in flash, the flash is closer to the lens. However, this doesn't mean the red-eye is unavoidable.

The following techniques can help reduce red-eye:

Increase the level of light in the room by turning on all the room lights. The added light will cause the subject's pupils to contract, reducing the reflective surface that causes red reflections.

- Have the subject look at a bright light (for example, a room lamp or a ceiling light) just before you take the flash picture. The bright light will reduce the size of the subject's pupils

- Have your subject look slightly away from the camera lens rather than directly toward it. This will help reduce or eliminate the reflections that cause red-eye.

- If your camera has a detachable flash, move the flash away from the camera lens. You can attach the flash to the camera with a flash cord and handhold it or clamp it to a nearby object.

Corny Joke Alert

[juggaleaux]

Face it, this is great news.