Network handwriting

Question

The teacher writes on the board, and we want to transfer all the information on the board over the network with low bandwidth in real time. How do we do this?

In one interview, I came across this question.

Answer 1

I had a feeling that the question was formulated so that no other computers could be used. If I had to guess, the interviewer wanted the interlocutor to understand that sending a picture of the entire board 20 times per second would be too intense with a bandwidth. Instead, perhaps they could understand that a piece of chalk can only write on one section of the board at a time and relatively write - you write a bunch of things before erasing. Thus, with our low throughput, we can simply send the current chalk position several times per second, and at our receiving end we just continue to draw pixels wherever there is chalk. so we just send 20 x, y pairs per second, not 20 whole bitmaps.

Answer 2

The easiest way, which does not require fancy technology or software and can be done with virtually no effort, is for one of the students to decipher the contents of the whiteboard on his laptop. A text editor can be something simple, like a network terminal that sends information to a remote computer as it is entered.

This is relevant:

http://thedailywtf.com/Articles/The_Complicator_0x27_s_Gloves.aspx

Answer 3

I think it depends on the type of board used. There are several new whiteboards that allow you to save its contents and print.

Personally, I think that along this path, if you have such a blackboard, you need to transfer a pair of x, y coordinates of the points drawn on the screen. Color information may not be needed if it uses only one color.

But I think that @Mehrdad Afshari's solution is the most common and affordable!

Answer 4

Use a digital camera?

To be serious, a real-time OCR engine can also be launched if the information needs to be extracted in a more subtle, more granular and textual way.