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How to use OpenCV constants in Python

📅 2015-Jan-20 ⬩ ✍️ Ashwin Nanjappa ⬩ 📚 Archive

OpenCV has a Python API. The Python function calls are well documented and listed along with the C and C++ calls. However, it is not obvious how to use the various OpenCV constants and enums in Python. These are typically named as CV_SOME_THING. For example: CV_WINDOW_AUTOSIZE.

import cv
win = cv.NamedWindow("haha", cv.CV_WINDOW_AUTOSIZE)

Here is a list of integer values for OpenCV constants that I frequently need to use:

CV_LOAD_IMAGE_UNCHANGED = -1
CV_LOAD_IMAGE_GRAYSCALE =  0
CV_LOAD_IMAGE_COLOR     =  1
CV_LOAD_IMAGE_ANYDEPTH  =  2
CV_LOAD_IMAGE_ANYCOLOR  =  4

Tried with: OpenCV 2.4.9, Python 2.7.3 and Ubuntu 14.04