This simple python ecript takes in as argument an image file
and then will show up three windows.
    - One window with trackbars to adjust upper and lower hsv values
    - Second window to show the range of upper and lower values on a 2x2 grid
      where the upper corner is for the upper hsv value and the lower right corner
      is for the lower hsv value.
    - Third window shows the input image file with the range of selected hsv values

I use it to find hsv ranges of colors.

All I need to do is take a picture of the region I want to extract and play with
the trackbars till the right values are obtained.
To minimize time of playing around with random values it's best to set the saturation
and value at their maximum and find the color in question just by varying the hue
after which saturatin and value can be taken into account to find the exact range.

A screen shot is attached with the script in action.


Dagim Sisay
February, 2017