4
$\begingroup$

Im sorry if it is a weird question, but I cant seem to find an answer for this. What does the signal going to the screen look like in more abstract sense? Does it code the values of each pixel in a huge matrix, is it a computational stream that instructs the screen what to present?

In other words, can I grab this signal by a "listening" device for example and deconstruct it with algorithms? Not just grab the signal and present it on another screen. For example, if it is a matrix of pixel values, then I can run face recognition algorithms for example, to see if the signal sent to the computer is a picture of face or not.

It might also depend on the type of screen? Say that it is a LCD screen.

edit: To elaborate, if I wanted to take the signal sent to the screen and scan it for text (NSA style), could I? If so, what should I know of the signal that Im collecting to actually do this? Disclaimer: Im not interested in spying on anyone.

$\endgroup$
7
  • 1
    $\begingroup$ I'm not sure if this is a computer science question. Are you more interested in the encoding of data in the driver/graphics card, or in what actually goes on in the wire? $\endgroup$
    – Raphael
    Jul 22 '14 at 10:24
  • $\begingroup$ Well I am interested in both. What does the driver/graphics card do to present information on screen, and subsequently what is the information sent to the screen consisting of. Im not in computer sciences, but Im working on something that is related to exactly this question. In other words; can I reverse engineer the signal sent to the screen (is what I want to do). $\endgroup$
    – Sevenius
    Jul 22 '14 at 10:40
  • 1
    $\begingroup$ 1) Encoding the image to be displayed is probably ontopic, but may be boring. Implementation issues are offtopic, though. 2) How to best transmit such things over wire is offtopic, too; that might be ontopic on Electrical Engineering. 3) I know that such devices exist, so you don't need to build your own. $\endgroup$
    – Raphael
    Jul 22 '14 at 12:06
  • $\begingroup$ Do you perchance have an example of 3)? $\endgroup$
    – Sevenius
    Jul 22 '14 at 12:37
  • 1
    $\begingroup$ This doesn't seem to be a computer science question. The cabling aspects are Electrical Engineering and the TEMPEST aspects are Information Security. $\endgroup$ Jul 23 '14 at 7:22
3
$\begingroup$

The memory you are asking about really exists and is called framebuffer. However, it's not easy to directly access this memory on modern computers, because it's intentionally hidden from user processes.

For more info - click here.

$\endgroup$

Not the answer you're looking for? Browse other questions tagged or ask your own question.