OpenCV Python! Where to start?
 

I have openCV installed with python but all the tutorials I am finding expect you to know a bunch of prior knowledge. Anyone have a good spot for a newbie to start. I have no prior knowledge of vision tracking or how it works. Thanks for you help.

Tomy

Re: OpenCV Python! Where to start?
 

There's a lot to learn about image processing in general. :)

I recommend the OpenCV tutorials/walkthroughs. Additionally, there are a bunch of examples distributed in the OpenCV source tree -- try to run them locally and see what they do, and then modify them in small ways.

Once you've done that, then I recommend reading various FIRST-related image processing whitepapers and related code (search ChiefDelphi for these), to get a feel for what types of techniques you can use to accomplish the tasks you need to accomplish.

You may find that GRIP is a useful tool (I haven't used it, but it looks promising) to experiment with image processing techniques and such. In particular, screensteps has a walkthrough on how to do image processing for the 2016 game using GRIP.

Re: OpenCV Python! Where to start?
 

Thank you. I've poked around with grip would you do the same processes as grip pip line? (Resize -> HSV/HSL -> Find Contours -> Filter Controus -> Pusblish to network table)

What is the difference between HSV and HSL?

Re: OpenCV Python! Where to start?
 

Yes, GRIP uses OpenCV underneath the hood, so a lot of the things that you can do with GRIP will easily map to OpenCV operations of some kind -- it just might add some extra magic to make it easier to use.

https://en.wikipedia.org/wiki/HSL_and_HSV

Re: OpenCV Python! Where to start?
 

Thanks for the in - site. Is the method I described before the best way to do vision tracking with openCV?

-(Resize -> HSV/HSL -> Find Contours -> Filter Controus -> Pusblish to network table)

Re: OpenCV Python! Where to start?
 

Generally speaking, that is the methodology we've used for image processing the last few years.

Re: OpenCV Python! Where to start?
 

Here's our OpenCV Python code... The numbers it gave me were always wrong but I think thats just because it wasn't tuned...

https://github.com/1684Chimeras/VEX_...a.py#L109-L207

note that line 150 doesn't error out but doesn't do anything either for some reason

and lines 126-143 are specific for grabbing an axis camera image

Re: OpenCV Python! Where to start?
 

Do you have any other tips? How to deal with lag or with blurry images? I've heard that has been a problem.

Re: OpenCV Python! Where to start?
 

See this thread (presentation by team 254 at championship conferences).

Re: OpenCV Python! Where to start?
 

Are you guys using grip with that code?

Re: OpenCV Python! Where to start?
 

Both. The top section (unhighlighted) is for GRIP. The bottom (highlighted) section uses raw openCV

Re: OpenCV Python! Where to start?
 

Interesting. Thank you for the code by the way it has helped me a lot. Do you use GRIP and open-CV in tandem??

Re: OpenCV Python! Where to start?
 

We calibrate with the GRIP than transpose those values over to OpenCV. Since the grip is already calibrated, there's a GRIP fallback option in case OpenCV failed

Re: OpenCV Python! Where to start?
 

I wrote some simple code to calibrate the camera in openCV using Track-bars. Would you like a copy of it? I haven't had time to implement it into working code yet I'm just using it to get the values for HSV and manually putting them into another part of code.

Re: OpenCV Python! Where to start?
 

This was my last year so I doubt I'll be able to make use of it. You can always post it on this sub forum if you think it merits use.