One of my favorite OpenCV tutorial, beginner friendly by freeCodeCamp.org.

A cute cat image, after the cv.Laplacian with data type cv.CV_64F, I converted it to unsigned 8-bit integer.

Here is another demo from the OpenCV tutorial. Face detection with haar_cascade. Although the performance was fairly good, it was a good start for further actions.

The rest of the images in this post are all zoomable, arranged into different mini-galleries.