Reliability of Pixy Camera?

[ItsTheRealAce]

So the PixyCam has a pretty good resolution, though depending on the year may not work well enough, we actually got ours to work to about the mid-line. Also the boulders do seem to be a problem. Also to get a live feed from the pixycam it isn't very possible, yet. (I'm hoping pixy releases an FRC version becuase they have an FLL version.) Though, my team didn't need to use anything other then what is provided by Pixy, the Pixycam and the Pixymon, to interface. We also didn't have any brown out problems. I do believe the PixyCam is very worth the cost, because on-board processing is better than off-board processing, and to set-up something like you would: need a camera, a kangaroo computer, and led lights. All this can come to a much more hefty price than the PixyCam. (which my team paid $100 for are setup and the other setup I'm talking about is nearly $200 or more.)

[s_forbes]

Originally Posted by electroken

We used the Pixy camera from week 5 on in Stronghold. It was the key to our autonomous high shot and a major contributor to our 9-11 high goal matches. The interface we chose to use was the simplest one (digital/analog X). I found it to be a bit touchy to set up, but once calibrated to the lighting in each venue it worked well.

We did change the lens from the stock one (75 degree horizontal field of view) to I think 51 degrees field of view.

To add to that: 230 had one of the top scoring robots in the Carver division and was the first pick during alliance selections. Talking to them in the pits, I was surprised that such a simple targeting system could work so well. OP, you should bug them for details, as it can clearly be used reliably!

-not a programmer.

[Bpk9p4]

After seeing how much great results people have had i started looking into the i2c communication. Any chance anyone has written the i2c communication for Labview?

[Gdeaver]

To teams that got the Pixy to work. Where did you shoot from? Did you shoot from the defenses? Did you have to be centered and perpendicular to the target? What did you do about getting 2 targets when positioned to the side and 2 targets were in view?

[electroken]

Originally Posted by Gdeaver

To teams that got the Pixy to work. Where did you shoot from? Did you shoot from the defenses? Did you have to be centered and perpendicular to the target? What did you do about getting 2 targets when positioned to the side and 2 targets were in view?

We shot from anywhere along the outer works and from along the left edge of the field (as viewed from our driver station). Our preferred and most practiced spot was halfway between the low bar and the wall along the left side.

The 2 target problem turned out to be no problem at all. Using the digital/analog X interface the Pixy gave the X position for only the largest target it saw. In every case that target was the goal most perpendicular to our catapult, and therefore the goal we wanted to be aiming at.

For clarification, we used the two signals from the Pixy as follows:
The digital output told the robot when the Pixy saw what we taught it to look for anywhere within its visual field. At that point the robot removed the yaw authority from our driver and aimed itself. A large indicator on the driver station told our operator when the robot was aligned and ready to shoot. At that same time full drive authority was returned to our driver, just in case we needed to relocate due to being defended.

[Harrison.Smith]

Originally Posted by Gdeaver

To teams that got the Pixy to work. Where did you shoot from? Did you shoot from the defenses? Did you have to be centered and perpendicular to the target? What did you do about getting 2 targets when positioned to the side and 2 targets were in view?

Mittens (1296) shot from most places, the best/favorite places were along the defenses in positions 3 and 4 for the safe shot, about 10ft past the low bar(when cycling) or between the batter and the defenses in front of the center goal. The driver was trained to know where the pixy would get confused (seeing two goals) and he would avoid those areas.

[AlexanderLuke]

Originally Posted by electroken

I found it to be a bit touchy to set up, but once calibrated to the lighting in each venue it worked well.

We did change the lens from the stock one (75 degree horizontal field of view) to I think 51 degrees field of view.

Two things:

1. What settings would you alter in order to get the best performance? Actual numbers on specific settings would be very helpful, I'm curious to know what you did to have the best performance possible.

2. What benefits did you find in changing the lens? What issues did you experience that made you look into changing the lens?


To anyone else who ran the Pixy this past year or have other experience, please feel free to chime in on your answers too.

[nardavin]

Thanks everyone for all of the great responses!

I just have one other question. Is there a way to pull the raw footage from the camera in the case that more advanced vision processing is needed? It looks like it may be possible via a USB connection but I don't see anything specifically referring to it in the USB api docs.

[electroken]

Originally Posted by AlexanderLuke

Two things:

1. What settings would you alter in order to get the best performance? Actual numbers on specific settings would be very helpful, I'm curious to know what you did to have the best performance possible.

2. What benefits did you find in changing the lens? What issues did you experience that made you look into changing the lens?

The Pixy is primarily a color sensor, so there is a balance to be found between consistently seeing what you want it to see with the exclusion of everything else. There are settings within the Pixymon calibration program to teach it how close is close enough to be considered a target, camera exposure, white balance, etc. We had some control over potential interference sources because we were looking for the specific orange of our targeting LEDs. We chose orange because it was not present in the field lighting. Others use green, YMMV. I don't know specific calibration numbers, as the robot is hibernating at the school.

The lens choice was also made to reduce the potential sources for false targeting. Using the Pixymon program to see what the camera saw, the 51 degree lens gave us the best view of the field with the least view beyond it.

The system was not perfect and needed tweaking along the way. The scrolling LED display along the arena perimeter at champs was occasionally orange and had to be considered. We also found that the end wall diamond plate at champs was highly polished, far more so than at our district events. That caused or robot to shoot at its own reflection once in autonomous (funny in hindsight). After teaching it to turn 30 degrees to starboard before looking for a target that was no longer an issue.

The Pixy can actually be set to look for 7 simultaneous colors. Who knows, that may be useful this year.

[Greg McKaskle]

I haven't used the pixy cam on an FRC robot, but I purchased one and I'll be using it for another robot competition. It has worked well in my initial testing with controlled lighting.

As stated. It is really more of a color-proximity sensor, a highly optimized and specialized sensor that does one thing well. If that is useful in the game, make use of it. If not, it is actually a pretty good exercise to make your own pixy cam using a USB camera and a little bit of processing code and extend it to do some additional measurements on the particles. But at that point, there isn't much need to incorporate the pixy cam. Just build your own. It is a great learning opportunity.

The optimization is the hard part. But I'm pretty sure most can make it fast enough for what they need on the robot. We aren't needing to measure the wing-beat speed of an unladen European swallow, are we?

Greg McKaskle

[Gdeaver]

Ok, I think we may have to revisit the pixy cam. Our judgement may have been premature. We went with grip on a Pi2b and an IP camera. The programmers are working on Opencv on a PI3 with IP camera and a native Pi camera. The difference is color blob detection vs object detection. The Pixy cam is a much simpler solution. One can not have enough tools in the tool box for next season. It seams that machine vision is a requirement for FRC teams that aspire to play at a high level. Our best trained operator could aim and shoot at best in 7 to 8 seconds. Our auto aim and shoot was average of 3 to 4 seconds and more consistent.

[Alsch]

It's nice to see how far the CMUcam platform has come. I remember trying to fuss with the old rs232 ones years ago.
Has anyone looked into the OpenMV camera? I don't hear as much about it, but I've been using one for a while and it's pretty nice, I wonder how they compare with one another. (buying more than one $60+ dev board at a time is somewhat difficult to justify to oneself and ones wallet.)

[Bpk9p4]

Originally Posted by Alsch

It's nice to see how far the CMUcam platform has come. I remember trying to fuss with the old rs232 ones years ago.
Has anyone looked into the OpenMV camera? I don't hear as much about it, but I've been using one for a while and it's pretty nice, I wonder how they compare with one another. (buying more than one $60+ dev board at a time is somewhat difficult to justify to oneself and ones wallet.)

do you know the updated rate for the OpenMC Camera

[Xanawatt]

Originally Posted by Bpk9p4

After seeing how much great results people have had i started looking into the i2c communication. Any chance anyone has written the i2c communication for Labview?

I have it working for java, and would be glad to share. It might be along the same lines as labview?(maybe)

[Bpk9p4]

Originally Posted by Xanawatt

I have it working for java, and would be glad to share. It might be along the same lines as labview?(maybe)

that would be great. Are you just getting the largest value or how do you have it working?