Conversion between any/all of BGR, RGB, and GBR may be necessary when working with

• Matplotlib pyplot.imshow(): M x N x 3 image, where last dimension is RGB.
• OpenCV cv2.imshow(): M x N x 3 image, where last dimension is BGR
• Scientific Cameras: some output M X N x 3 image, where last dimension is GBR

Python BGR to RGB code: RGB_BGR_GBR_conv.py

BGR to RGB

OpenCV image to Matplotlib

rgb = bgr[...,::-1]

RGB to BGR

Matplotlib image to OpenCV

bgr = rgb[...,::-1]

RGB to GBR

gbr = rgb[...,[2,0,1]]

Axis order for Python images

• 3-D: W x H x 3, where the last axis is color (e.g. RGB)
• 4-D: W x H x 3 x 1, where the last axis is typically an alpha channel