test various debayer patterns on images from DSV-IV camera (COLOR_BayerGB2BGR and COLOR_BayerGR2RGB worked for me)

test-debayer-fits.py

# https://docs.opencv.org/3.1.0/d7/d1b/group__imgproc__misc.html#gga4e0972be5de079fed4e3a10e24ef5ef0a353a4b8db9040165db4dacb5bcefb6ea
import cv2
# http://docs.astropy.org/en/v0.2.3/io/fits/index.html
from astropy.io import fits
image_file = 'c:/temp/tree-nocolortype.fit'
image_data = fits.getdata(image_file, ext=0)

cv2.imwrite('c:/temp/COLOR_BayerGB2BGR.png',  cv2.cvtColor(image_data, cv2.COLOR_BayerGB2BGR ))

cv2.imwrite('c:/temp/COLOR_BayerBG2BGR.png',  cv2.cvtColor(image_data, cv2.COLOR_BayerBG2BGR  ))

cv2.imwrite('c:/temp/COLOR_BayerRG2BGR.png',  cv2.cvtColor(image_data, cv2.COLOR_BayerRG2BGR ))

cv2.imwrite('c:/temp/COLOR_BayerGR2BGR.png',  cv2.cvtColor(image_data, cv2.COLOR_BayerGR2BGR  ))

cv2.imwrite('c:/temp/COLOR_BayerBG2RGB.png',  cv2.cvtColor(image_data, cv2.COLOR_BayerBG2RGB  ))

cv2.imwrite('c:/temp/COLOR_BayerGB2RGB.png',  cv2.cvtColor(image_data, cv2.COLOR_BayerGB2RGB  ))

cv2.imwrite('c:/temp/COLOR_BayerRG2RGB.png',  cv2.cvtColor(image_data, cv2.COLOR_BayerRG2RGB   ))

cv2.imwrite('c:/temp/COLOR_BayerGR2RGB.png',  cv2.cvtColor(image_data, cv2.COLOR_BayerGR2RGB   ))