Tracking Rectangles

[faust1706]

Originally Posted by yash101

I have wanted to design a vision system to work like that and calculate the distance from the target without range sensors or any other sensors. I also wanted to skip the Kinect because of how hard it is to interface to the robot, and it's slow speed. This is exactly the routine that I wanted to do. Now, I know how to implement it. Thank You!
Also, if I am not wrong, does it follow the laws of perspective that explain how an image looks smaller as it is farther away from your eyes, in this case, the camera.

Here's and O: O
Look at it up close. doesn't it look large?
Now look at it five feet away. It should look much smaller now.
If I am not wrong, I think that is how this is supposed to work!

is it still too late to contribute? I've been teaching those interested in my team during this preseason computer vision. I posted a white paper on here describing my methods of using camera pose estimation for rebound rumble (note, this is very complicated mathematics, I don't recommend it unless you are up for a big challenge) Pose could have been used for this year, too, but that pesky pyramid, so basic trig sufficed. I'm in the process of writing a scholarly (I guess you'd call it) paper describing my program from ultimate ascent (for the purpose of submitting it to our the missouri symposium and have it compete at Intel ISEF and ISWEEEP, the kid who won isef was on daily show last night) You can view our vision system set up from our website if you like. *we used a single board computer, O-Droid X2. It is our toy now essentially. So much fun to play with.

Anyways. Is anyone doing anything with vision this preseason? I've been working with some professors at wash u, Missouri s&t, and harvey mudd to make a camera pose estimation with a known rotation matrix. Turned out to be a lot more math intensive than the 3 of us first thought...the program will be done before build season and I'll have it up online somewhere so whoever is welcome can look at it. I'll make it as....educational as I can with comments, but comments can only do so much (which turns out to be a lot). If it is another game where there is reflective tape that can be used to assist in scoring, which there has been every year I've been in FIRST (starting with logomotion), then I'll put up a working vision code that returns distance on the x-z plane and x-rotation to the center of the target at a reasonable time during build season.

[Ginto8]

Originally Posted by faust1706

Anyways. Is anyone doing anything with vision this preseason? I've been working with some professors at wash u, Missouri s&t, and harvey mudd to make a camera pose estimation with a known rotation matrix. Turned out to be a lot more math intensive than the 3 of us first thought...the program will be done before build season and I'll have it up online somewhere so whoever is welcome can look at it. I'll make it as....educational as I can with comments, but comments can only do so much (which turns out to be a lot). If it is another game where there is reflective tape that can be used to assist in scoring, which there has been every year I've been in FIRST (starting with logomotion), then I'll put up a working vision code that returns distance on the x-z plane and x-rotation to the center of the target at a reasonable time during build season.

I wrote my team's vision system last year, but this preseason (and hopefully build season), it's in the hands of one of the newer team members -- I'm graduating this year. Your pose estimation project sounds quite interesting to me, though. Thinking through it a little, it seems that for a rectangular target you could use the ratios in length of opposite edges to find the Euler angles of its plane. To figure out the formula to calculate that, though, I'd need some paper and a lot of pacing. I'd definitely like to see your work once it's complete!

[faust1706]

Originally Posted by Ginto8

Thinking through it a little, it seems that for a rectangular target you could use the ratios in length of opposite edges to find the Euler angles of its plane. To figure out the formula to calculate that, though, I'd need some paper and a lot of pacing. I'd definitely like to see your work once it's complete!

If you sit down and think about it for a second, you realize that the whole rotation matrix can be solved without doing pose. the object points are all on a single plane, which in itself makes things simpler, but it also IS the YZ, and it doesn't go into the XY plane at all, which is nice. That means that roll is constant. You can calculate pitch and yaw by proportions with the FOV vs image resolution. Great, now we have the rotation and camera matrix known. the only thing to solve for is the translation matrix. Hurray! This can be done in 2 ways, "plugging in" the rotation matrix into the standard pose equations, or using geometry. I did the geometry approach already, it works. Coded and everything. Currently doing the linear algebra approach. I want to know which one is quicker fps wise. Then, since my team loves gyros but hates the gyro climb, I'm going to use my "pose" as a check on the gyro. So when I have a pose solution, it will fix the gyro readings. I trust my linear algebra more than a gyro that has climbed over 10 rps in the pits.