OpenCV trackbars and OS X


Notoriously poor coding by the OpenCV group here, with trackbars being barely functional.

The two main issues are:

  • Trackbar value is not displayed
  • Trackbar ordering is not the same as the order in which they are coded
    • In fact is is apparently random, or pseudo-random – it is a logic, but it is not clear what that logic is

Additional issues are:

  • Named windows containing only trackbars do not move with moveWindow()
  • Named windows containing only trackbars do not resize with resizeWindow() – check this!!!
  • Code execution pauses when a trackbar is adjusted
  • Performance hits
    • When trackbars are in the same window as the image being adjusted

I have seen these issues consistently in Python. I am not sure if they all occur in C++ as I haven’t tested for them (yet).

Version info:

  • OS X: High Sierra
  • Python 3.7/3.9
  • OpenCV:

Continue reading OpenCV trackbars and OS X

Course notes: Self driving Pi Car


This project is poorly presented, with no real logical video ordering. However, it covers a lot of topics and the project starts out as an ultrasonic Arduino controlled obstacle avoidance robot and works up to an optical path following robot, and then a CNN lane following robot… a real jack of all trades!

Notes from:

Next the keyboard and joystick videos from the Playlist:

Then, finally


These three videos are related to self driving simulation using Nvidia

Continue reading Course notes: Self driving Pi Car