Screen dimming according to the barrier in front of the screen for CSIT6910 HKUST.
Brief description: Nowadays, there are numerous large display devices, and traditional blackboard is being replaced gradually. Although it is greener than using eraser and chalk to write on blackboard, and more convenient for the teacher so that he/she does not need use much time writing repeatedly, the power usage still has room for improvement. A 51-inch television would cost nearly 200W, and a larger one would certainly cost more power. It would be much better if, when someone such as a teacher stands in front of screen, the part of the screen overlapped by the teacher can dim automatically to save unnecessary power usage.