# unmanned ground vehicle

Discussion in 'Robotics & Mechatronics' started by prerna123, Oct 3, 2016.

1. ### prerna123New Member

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Hi, I am working on design of an unmanned vehicle , i want to know how to choose a communication channel or device. I have to transmit 640 x 480 px at 10 frames/sec. and area to span is 500m or more Non Line of Sight. I have read about XBee will it suit my requirement ? is this calculation correct: 640 x 480 x 10~ 3mbps is the data rate. If anyone has worked on this please guide me..

2. ### specWell-Known MemberMost Helpful Member

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Hi prerna123,

One approach to reduce the amount of data with video is to just send change information. Of course, the benefit of this approach depends on how fast the scene changes from one frame to the next.

spec

3. ### prerna123New Member

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Ok, but is my way of calculating data rate correct?

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5. ### specWell-Known MemberMost Helpful Member

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I assume that by 3mbs you mean, 3 Mega bits per second (3Mbs).

3 Mbs would give one bit per pixel which would allow two logic levels, black and white say, for each pixel- a very pixelated image.

In general, it is taken that the human eye can resolve 256 color levels, and that is the best that displays can produce too.

As 256 levels requires 8 bits, and as a pixel is effectively made up, of three sub pixels, red, blue, and green (RGB), three bytes would be required per pixel.

Thus, for a 640 pixel by 480 pixel display, with 8 levels for each color, you would need a data rate of: 640 * 480 * 10 * 3 * 8 bits per second or, 73 Mega bits per second.

That is the theoretical calculations about the data rate for a high end display, but over the years the situation has become much more corrupt and manufacturers use figures for marketing advantage rather than science. This is especially the case in digital photography and camera resolutions.

So, you need to investigate/establish what you intend to display, and what pixel bit depth you need and, also, what display standard you intend to use. I think 640 by 480 is the same pixel resolution as Video Graphics Array (VGA) which has a specifications that you will find on the net.

spec

PS: I see you are from India: care to tell us where and put it next to 'Location' on your user page so that it displays in the window at the left of your posts. That will be a big help to those of us replying to your questions.

Last edited: Oct 7, 2016
6. ### prerna123New Member

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Alright that means calculation is correct, so now i need to choose communication channel.

7. ### prerna123New Member

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Thank you so much for helping me out

8. ### specWell-Known MemberMost Helpful Member

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My pleasure prerna123.

spec