Centering a reference pattern under a camera through the movimentation of two axis

[FM82]

Hello again, i have some doubts that i hope you can help dissipate.

I need to develop an algorithm capable of centering a reference pattern under a camera (by the way, i have the Vision Library). To centering the pattern i can control two motor that move two axis (x and y); the message that i can send to the motor permit me to control the distance that a single motor can travel in a single shot (distance and velocity, it's simplified G Code).
The better solution is to calibrate the system and transform pixel's coordinates in mm's coordinates and then program the motors to travel the right distances. But what if i can't go this way? I've been thinking on PID controller but i'm not sure if i can make it works in this case.

Any help would be appreciated, thank you very much.

Francesco.

[Dagaror]

Hi Francesco,

I don't know if you still are in trouble. 

I think the better solution is to calibrate the image with a grid and later you will acquire the x and y axis position in millimeter. Later you pass the information to the driver which controls both motors and you can elaborate a PID or whatever the driver allows you.

http://zone.ni.com/reference/en-XX/help/370281M-01/nivisionlvbasics/perspective_and_nonlinear_distor...

http://digital.ni.com/public.nsf/allkb/815CFD0DACE4AFB08625770F004EE84E

http://digital.ni.com/public.nsf/websearch/F05924D50AD6472B86256F320075CDBF?OpenDocument

http://www.ni.com/example/25897/en/

https://www.youtube.com/watch?v=rv_3bUnS1pE

https://www.youtube.com/watch?v=eWqq65ZZ0NQ

Good luck and enjoy!

[FM82]

Thank you Daragor. I've managed to do it in another way but i think that the links that you give me are still useful so: thank you again!!