Raspberry Pi LESSON 52: Understanding and Using Trackbars in OpenCV

Announcing the Most Awesome Raspberry Pi Lessons of All Times! This time we RUMBLE!
In this class series, we will be using the most excellent Sunfounder Ultimate Raspberry Pi kit, available here: (Affiliate Link)
amzn.to/3tSk9Mo
or for our UK friends, amzn.to/3I5d401
In today's lesson I show you how to create and use trackbars in openCV. The example I show will allow you to do the homework.
If you want to grab those cool little straight jumper wires I am using to keep my breadboard builds neat and clean you can snag a box of them here:
amzn.to/36NyfHq
If you guys are interested in the oscilloscope I am using, you can pick one up here (affiliate link):
amzn.to/3v13Mhl
You guys get your hardware ordered so you can follow along at home!
You will also need a Raspberry Pi. I suggest the Raspberry Pi 4. If you do not already have one, this is the most suitable gear I could find:
amzn.to/3pBMfKm
The Raspberry Pi's are sort of pricy right now, so you can look on ebay or elsewhere to see if there are any deals. You will need a SD card. If you do not already have one, this is a good one:
amzn.to/3KcXTn2
I like using a wireless keyboard and mouse to have fewer wires. You can certainly use your USB keyboard and mouse, but if you want a nice wireless one, this one works on the pi. We demonstrate this by using a button switch to control a LED.
amzn.to/36Rv9Sk
You guys can help me out over at Patreon, and that will help me keep my gear updated, and help me keep this quality content coming:
/ paulmcwhorter
[Disclosure of Material Connection: I am a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. ]
#tackbars
#opencv
#raspberrypi

[@wilsonlittle4833]

Awesome, Awesome, Awesome! That's my opinion of your videos. The last several lessons on understanding and manipulating video data has simply been a thrill. I wrapped up today's homework with pure excitement and enjoy that I can do these things using python, a raspberry pi, and a camera. THANK YOU!

[@paulmcwhorter]

Excellent!

[@arguedas02]

I can’t thank you enough for what you do, God Bless you....

[@paulmcwhorter]

Thank you, and may God richly bless you as well.

[@pralaymajumdar1206]

Outstanding and very very interesting lesson sir.. Thank u very much🙏

[@stephenlightkep1621]

Thanks Paul. I am another step closer to building a golf ball tracker.

[@qzorn4440]

Just finished entering this valuable OpenCV lesson in my Raspberry Pi notebook. The ROI is so exciting and powerful. 😎 Paul, thank you very much. Very enjoyable.

[@MrCameronMoore]

I see the power of trackbars, and I can also see the trouble I can get myself into : - ))

[@alejandrolemus7076]

Hey Paul, really enjoying your lessons with the introductions to Arduino. Your lessons are really enjoyable. Just wanted to drop a comment on your most recent videos to say that your older content still holds up greate and I appreciate the effort you put into these.

[@gonzagagration9391]

Most thankful to you Paul for your school..

[@amarbakshi2839]

Giddy up... I could do this exercise myself since I understood the concepts. Thanks Paul..

[@charlotteswift]

Here is my video for lesson 52: th-cam.com/video/pURTqNYExjY/w-d-xo.html Many apologies for the lighting, video quality, War in Ukraine, global warming etc!

[@cbrombaugh]

I AM LEGEND! This is interesting and fun stuff. My program ran at 14 FPS. Thanks for all your time and effort, Paul.

[@paulmcwhorter]

LEGEND!

[@scottwait3585]

Thanks Paul!

[@parshvapatel8484]

I recently managed to install linux on my old smartphone but is it possible to add something like ft232h or raspberry pi pico to make it something similar to raspberry pi 3 as it is really hard to get hands on to raspberry pi 3, 4

[@alistaircook1997]

Enjoying the rasberry pi lessons, I have assembled the Sunfounder pan an top hat for future pan and tilt lessons, but I am unable to find a command to rotate the image as the camera on this unit is upside down.
Do you have a command that rotates as FLIP did on the Legacy camera system, i've search for one on the internet, but found none.

[@paulmcwhorter]

You can do it with opencv. After you grab the frame try:
frame=cv2.flip(frame, -1)

[@alistaircook1997]

@@paulmcwhorter Thank you this worked, and a fast reply. Spent hour searching for a solution, should have ask you first.

[@arlo4051]

Homework done sorry for the length slow with the trackbars. th-cam.com/video/-I5k7Npjkok/w-d-xo.html

[@charlotteswift]

Here is my non-homework for lesson 51 (good theory, bad execution!) : th-cam.com/video/4_5SaSfaorc/w-d-xo.html

[@paulmcwhorter]

Nice solution

[@LarsBudek]

I love your lessons....
You have set Boxw to dispW and X Pos to dispW. When you create the retangle, the end coordinate is xPos+boxW. Will it not give an error if the starting position and width added together are greater than DisplayW... The same in the y direction

[@charlotteswift]

@Lars Budek Rather than asking this question, why don't you try it out for yourself? This is much better way of learning.
There are 2 possible outcomes:-
Either, the program blows up in which case you can leave a comment for Paul saying that he's made a mistake.
Or, only the portion of the rectangle that is within the frame is visible in which case you don't leave a comment.
I could tell you what happens but that would spoil the surprise😁

[@hammadahmed3409]

Homework th-cam.com/video/DkNaOQ0m8I0/w-d-xo.htmlsi=Oc9vipu_QYHbgsQT

[@paulmcwhorter]

Excellent!