Finding where you are in the field

[Djur]

I coded this using a combination of the ADXL345_I2C in the KoP and Ultrasonic rangefinders, but we're not going to use it because it's fairly useless to know where the robot is in this game. For shooting, all you need to know is the width/height of the rectangle on the backboard and the angle to it.

[pfreivald]

Why would it be fairly useless to know where the robot is? You always know where the hoops are, so if you know where the robot is (and how it's oriented), you know where to shoot!

[davidthefat]

Personally, I would do this: We know the size of the rectangle to a margin of error of a couple millimeters. We can calculate the relative distance from the basket by seeing the angle of rotation and size on the image.

[Djur]

Originally Posted by pfreivald

Why would it be fairly useless to know where the robot is? You always know where the hoops are, so if you know where the robot is (and how it's oriented), you know where to shoot!

Using the camera and the code supplied by National Instruments to find position and angle is much easier and more accurate than using the gyro (off by up to 7* in either direction) and ultrasonics, which can be interfered with by other ultrasonics. Also, this.

[shuhao]

Originally Posted by Djur

Using the camera and the code supplied by National Instruments to find position and angle.

First of all, Where is this code?

Second of all... Oh come on where is the fun in using their code! ;p (even though if it works.. I probably will)

[Djur]

Stick this in whichever class you have camera tracking:

import edu.wpi.first.wpilibj.image.*;

NI's code is in NIVision.java

If you don't use Java, I can't help you.

[shuhao]

Originally Posted by Djur

Stick this in whichever class you have camera tracking:

import edu.wpi.first.wpilibj.image.*;

NI's code is in NIVision.java

If you don't use Java, I can't help you.

I am using Java.

Looking at the documentations.... there are a very scarce amount of it for the class..

[Djur]

Check out this thread.

[Se Hyun Han]

I've been pondering, why would stereo vision be difficult? Is it due to the improbability of connecting two cameras to the D-Link or is it due to the difficulty in simply using the two cameras?

[Jared Russell]

Vision tracking using Java this year will be more difficult than in the other languages, unfortunately. Unless there is an update released soon, not all of the NIVision capabilities useful for rectangle tracking have been wrapped by WPILibJ (whereas in C++, they are all available).

It is unfortunate that despite the supposed "equal" capabilities of each officially supported language, in 2012 there are very unequal capabilities when it comes to vision processing.

We are looking into offboard (Driver Station laptop or separate single board computer on the robot) solutions to vision processing, but these capabilities are very poorly documented at the moment. We have written/modified JavaCV/OpenCV code to reliably track the goals, and are now playing around to find a way to get that code to send back it's "answers" to the cRIO, using either NetworkTables or a separate socket interface.

[pfreivald]

Originally Posted by Djur

Using the camera and the code supplied by National Instruments to find position and angle is much easier and more accurate than using the gyro (off by up to 7* in either direction) and ultrasonics, which can be interfered with by other ultrasonics. Also, this.

You're not thinking what I'm thinking.