ImageMagick / OpenCV equivalent

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Hi.

Sorry for the noob question. I started a project with ImageMagick, and for performance reasons I'm trying to move it to OpenCV. I'm having a hard time to reproduce the exact same steps, and the documentation does not help. Here are the 'convert' operations I use (followed by # openCv when I have found something approaching) :

-negate # cv2.bitwise_not(img)
-normalize # cv2.normalize(img,img,0,255,cv2.NORM_L1)
-contrast-stretch 80%x10% # ???
-threshold 60% # cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY | cv2.THRESH_OTSU)[1] ???
-morphology Erode Octagon:1 # cv2.morphologyEx(img, cv2.MORPH_CLOSE, kernel) ; cv2.erode(img, None, iterations=3)
- blur x2 # cv2.GaussianBlur(img, (3, 3), 0)

Any help would be greatly appreciated.

Thanks.