(from https://www.scivision.co/numpy-image-bgr-to-rgb/)
Conversion between any/all of BGR, RGB, and GBR may be necessary when working with Matplotlib expects M x N x 3 image, where last dimension is RGB.
OpenCV expects M x N x 3 image, where last dimension is BGR.
Scientific Cameras, some of which output an M X N x 3 image, where last dimension is GBR