Color detection problem.

 I am trying to move my bot to the corresponding color in the image. I tried some algorithms but it didn't work out. I would be really happy if you could help me with this thing. I would be much obliged if you could provide me some kind of sample code or something. If you have this code please share the code with me.

Here's the image https://picasaweb.google.com/113606847351479489219/January142012#5697511886387683426

I am trying to move my bot to the black rectangle corresponding to the red.

Thanks in advance.

[Chandra Kurniawan]

Your picture not found!

Please send me correct link.

[Image Analyst]

What does "the black rectangle corresponding to the red" mean? Since you've been around here a while I would have thought you've already seen this: http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[Image Analyst]

What is a bot? You mean a robot? Like you're somehow communicating with a robot to move the robot to locations on the floor that are covered with colored paint or stickers?

Answer 1

[i Venky]

Sorry guys. I uploaded it but I don't know why it didn't show up. Anyway I am uploading it once again.

https://picasaweb.google.com/113606847351479489219/January142012#5697511886387683426

The robot is in the black circle at the bottom. I need to move the robot to the left. I don't have problem with the serial communication. The problem is with the image processing part code. I would be really happy if you could help me.

Thanks in advance

[Image Analyst]

I don't understand. Your image looks like you're doing a simulation yet you say you have a robot that is taking orders from your computer, perhaps via the Instrument Control Toolbox or something similar. So if you send out a signal through your serial communications line to move your robot to some real world location in a real room, on a calibrated playing field where distances are measured in meters, then how does that relate to your computer graphics simulation where things are measured in pixels?

Answer 2

[Walter Roberson]

http://www.mathworks.com/matlabcentral/fileexchange/32374-matlab-support-package-for-arduino-aka-arduinoio-package

http://web.mae.cornell.edu/hadaskg/CreateMATLABsimulator/createsimulator.html

http://www.mathworks.com/matlabcentral/fileexchange/32698-matlab-toolbox-for-the-irobot-create-v2-0

Answer 3

[i Venky]

Actually I would draw these figures on the ground later. The robot is in the position denoted by the black circle. What I need is some what like this-

I need the robot to move to the position of the black square near the red one. For that I want to first detect where the red square is. After that using left,right,up and down direction commands (i.e. serial data corresponding to left, right, up and down) the robot has to go to that position.

Assume that

left- 00,
right- 01,
up- 10,
down-11

I know how to do the serial communication using Matlab.

So there's no need of the code for serial communication. Let's assume that out(a) will send the value contained in 'a' serially (a has the value for direction - 00 or 01 or 10 or 11).

All I need is the algorithm

Thanks in advance

[Image Analyst]

Yes, but you didn't answer my questions in my comment to your first answer to your question. The real world with your real robot have different images (presumably from one or more cameras) and a different coordinate system than your simulation (the computer graphics image).

[Chandra Kurniawan]

@I Venky :

Hi,

I think you are not using appropriate methods.

That is true if you are using image processing techniques to detect the color of objects.

But, is the wrong way if you move the robot in image pixels.

It's better if you use vector. However pixel coordinates different with vector coordinate.

It's better if you convert this image into vector first.

You can make it with the command 'patch' from Matlab and then you can move these coordinates through 'Xdata' and 'Ydata'.

[i Venky]

I would be really happy if you could give me some kind of sample code.

Thanks in advance.

[Image Analyst]

Yes, I believe you would. But that's asking way too much to have us give you code to control movement of a robot around a room while showing a simulation of it on the screen, particularly when you haven't been forthcoming in answering questions directly. You already have code for communicating with your robot over a serial line, and my File Exchange has several methods for finding colored patches in an image. You now have all the tools you need. I think the rest of your project is for you to adapt and integrate those concepts into your project.

Answer 4

[i Venky]

Assume that I have colored my robot in a different color (say purple).

Answer 5

[Walter Roberson]

As you already have the other parts, all you need is

left = [0 0];
right = [0 1];
up = [1 0];
down = [1 1];

%calculate number of times need to go Left, Right, Up, Down. Then

for K = 1 : NLeft; out(left); end
for K = 1 : NRight; out(right); end
for K = 1 : NUp; out(up); end
for K = 1 : NDown; out(down); end

I would not have thought that would be a conceptual difficulty ?