help me with increased colour sensing range

[aruna1]

hello guys I'm new to robots.i have a robot competition in my university and need to make a robot.what i need to know is

• is there any way to sense black color from distance (not like in black line following robots).(like from about half meter distance black mark identifying)
  
  is there any way to use lasers or IR to do this long range detection?

what i want to happen is to detect black arrow draw on the floor without going near to it.robots should be able to detect arrow from distance so it can go to the arrow

i hope you understand me(coz my English is terrible )

thanks,i hope you will response soon

[airman00]

use a vision sensor like the CMUcam,AVRcam, or Blackfin camera.

[aruna1]

use a vision sensor like the CMUcam,AVRcam, or Blackfin camera.

thanks for quick response

well how much does they cost and what is the cheapest?can you guide me to a proper tutorial.and cant we use cheaper method. like normal color sense method with increased range(if there anyway to increase the range-can we use lenses? )

thanks again

[Ro-Bot-X]

Black does not reflect light well, so only the camera is able to see a black arrow from a distance, and help with determining the direction it points. A camera will return coordinates of a binding box for the color blob you tell it to search for (black in your case). Depending on the arrow shape and size, the distance from the camera and the arrow, the angle the arrow is pointing at, the binding box shape will be different, but still rectangular or square. You need to get pretty close to be able to detect the direction the arrow points as the camera will return a few close together binding boxes.

[aruna1]

Black does not reflect light well, so only the camera is able to see a black arrow from a distance, and help with determining the direction it points. A camera will return coordinates of a binding box for the color blob you tell it to search for (black in your case). Depending on the arrow shape and size, the distance from the camera and the arrow, the angle the arrow is pointing at, the binding box shape will be different, but still rectangular or square. You need to get pretty close to be able to detect the direction the arrow points as the camera will return a few close together binding boxes.

i guess camera is too much for me as I'm a beginne :-[r.i was thinking about using a lens to focus small area  (like pin hole) at a time and read it with phototransistor or a photoresistor.do you think this will work?

[Admin]

These tutorials might help you some:
http://www.societyofrobots.com/robot_faq.shtml#camera_microcontroller
http://www.societyofrobots.com/sensors_color.shtml


Unfortunately photoresistors have a range of only an inch or two max. Using a camera is the only method to detect specific shapes of color at far distances.

[aruna1]

These tutorials might help you some:
http://www.societyofrobots.com/robot_faq.shtml#camera_microcontroller
http://www.societyofrobots.com/sensors_color.shtml


Unfortunately photoresistors have a range of only an inch or two max. Using a camera is the only method to detect specific shapes of color at far distances.

thanks