robot path finding

[superchiku]

i tried to use the wavefront path finding but it didnt workout...now ...my problem is i know the xy coordinates of the red balls...and also i know the xy corrdinate of my robot..how do i make the robot move to all the posns of the red balls...catch each one and then finally put them in another red couloured goal whose xy coordinate is also known...

[Admin]

i tried to use the wavefront path finding but it didnt workout

Where did you get stuck? What is your hardware/sensors/mcu?

[superchiku]

only the cam....the prooblem is if i take a single image then i may disturb the balls while iam going to catch another one...thats why,,

[Admin]

If you use an overhead camera, not mounted on the robot but instead on your ceiling, this will be pretty easy.

If you wanted the camera on the robot, you first need to develop an algorithm that detects objects with your camera.

[superchiku]

am using the overhead cam...thing is..i need to find out the oriendtation of the bot also...i mean at which angle it is pointing then i need to turn it in the balls direction and make it move...this orientation part is wat is affecting me...

[Admin]

i mean at which angle it is pointing then i need to turn it in the balls direction and make it move...this orientation part is wat is affecting me...

Just cheat and put a black/white picture on top of the robot. For example a box and a circle, where the orientation of the pictures is the orientation of your robot.

[superchiku]

ya i have done that added an arrow...but the thing is how do i find out the angle at which the arrow is with respect to the horizontal line.. .?

[Admin]

ya i have done that added an arrow...but the thing is how do i find out the angle at which the arrow is with respect to the horizontal line.. .?

Hmmm a bit complicated . . . I'm just going to give you the pseudocode . . .

The arrow is a rectangular shape . . . so find the x and y coordinates of both ends of the rectangle.

Next, use basic trig to find the angle of that line to the horizontal.

[superchiku]

via blob detection i can find the xy coordiante of the blob...but htenn how to finf the xy of the ends??

[cosminprund]

Put two dots/discs of different color on the bot. Run blob detection on each color, you got the coordinates for the two points. That should be enough.

[superchiku]

GOOD IDEA BUT
wat abt the other coloured blobs in the arena which are of the same colour wont they also be detected in the blob detection...then how do i differentiate them from the dots on the bots...

[Admin]

Put two dots/discs of different color on the bot. Run blob detection on each color, you got the coordinates for the two points. That should be enough.

I feel stupid, this is what I meant to say

GOOD IDEA BUT
wat abt the other coloured blobs in the arena which are of the same colour wont they also be detected in the blob detection...then how do i differentiate them from the dots on the bots...

Count the pixels in the blob. Your robot has the pixel count closest to what you preprogram it as. Also, its the only two blobs of two specified colors next to each other.

[superchiku]

ummm wat does that mean/???

[Admin]

Another idea . . . don't put any markers on your robot at all and . . .

Tell your robot to drive straight. Compare the location of your robot before moving, and after, and you'll know which way its pointing. My computer vision tutorial will tell you which algorithm to use

Whats great about this is that it'll work with any type of robot, and even multiple robots in the same image.

[superchiku]

i didnt update this post ..i have cr8ed a blob detection alg and have attached a video...it gives the size of the 3 biggest blobs along with their centre's ...possibly now i can use it for path finding.. .... see my video...it tells u all..

[superchiku]

umm..which tutorial to read in the computer vision tutorial which shows the orientation of the bot . ..

[Admin]

motion detection, silly

[superchiku]

oi.... thats a nice idea though... ..................... rofl. .... but what if the balls are displaced for some reason by the bot.. .