# OpenCVTest1.py

# this program opens the file in the same directory names "cam.jpg" and displays the original image and a Canny edges of the original image

import cv2
import numpy as np
import os

###################################################################################################
def main():
    imgOriginal = cv2.imread("cam.jpg")               # open image

    if imgOriginal is None:                             # if image was not read successfully
        print "error: image not read from file \n\n"        # print error message to std out
        os.system("pause")                                  # pause so user can see error message
        return                                              # and exit function (which exits program)
    # end if

    imgGrayscale = cv2.cvtColor(imgOriginal, cv2.COLOR_BGR2GRAY)        # convert to grayscale

    imgBlurred = cv2.GaussianBlur(imgGrayscale, (5, 5), 0)              # blur

    imgCanny = cv2.Canny(imgBlurred, 100, 200)                          # get Canny edges

    cv2.namedWindow("imgOriginal", cv2.WINDOW_AUTOSIZE)        # create windows, use WINDOW_AUTOSIZE for a fixed window size
    cv2.namedWindow("imgCanny", cv2.WINDOW_AUTOSIZE)           # or use WINDOW_NORMAL to allow window resizing

    cv2.imshow("imgOriginal", imgOriginal)         # show windows
    cv2.imshow("imgCanny", imgCanny)

    cv2.waitKey()                               # hold windows open until user presses a key

    cv2.destroyAllWindows()                     # remove windows from memory

    return

###################################################################################################
if __name__ == "__main__":
    main()