Dr. Ahmed G. Abo-Khalil

Electrical Engineering Department

Optical feedback

Optical feedback is the optical equivalent of acoustic feedback. A simple example is the feedback that occurs when a loop exists between an optical input, e.g., a video camera, and an optical output, e.g., a television screen or monitor. (A simple example of optical feedback is also an image cast between mirrors.)

In the GIF movie, and the JPEG still image examples (right), light from a candle is received by a video camera, amplified and then sent by cable to a monitor projecting electron beams to a monitor screen. The image on the monitor is then captured by the video camera again, and fed back to the monitor in a continuous loop.

The original light source, in this case from the candle, can then be extinguished, while the feedback loop continues. For each loop the image is doubled and the image interferes with itself. The electronic loop moves with near light speed, but as the resulting image is projected onto the phosphor dots on the inside of the screen by the electron beam, the phosphor points take time to begin and stop glowing, and this creates a persistence which prevents the patterns changing too fast, and thus they survive long enough to be perceived. (More recent types of screens, such as plasma display, LCD and LED, can also be used)).

Office Hours

Monday 10 -2

Tuesday 10-12

Thursday 11-1

My Timetable


Contacts


email: [email protected]

[email protected]

Phone: 2570

Welcome

Welcome To Faculty of Engineering

Almajmaah University


IEEE


http://www.ieee.org/

/

Links of Interest


http://www.utk.edu/research/

http://science.doe.gov/grants/index.asp

http://www1.eere.energy.gov/vehiclesandfuels/

http://www.eere.energy.gov/


Travel Web Sites

http://www.hotels.com/

http://www.orbitz.com/

http://www.hotwire.com/us/index.jsp

http://www.kayak.com/

Blackboard

ستقام اختبارات الميدتيرم يوم الثلاثاء 26-6-1440

حسب الجدول المعلن بلوحات الاعلان

Summer training

The registration for summer training will start from 5th week of second semester

Academic advising

Class registration week 1

برنامج التجسير




إحصائية الموقع

عدد الصفحات: 2879

البحوث والمحاضرات: 1280

الزيارات: 64098