message: Update canny_detector.markdown
diff: @@ -68,7 +68,7 @@ Code
  -# **What does this program do?**
  - Asks the user to enter a numerical value to set the lower threshold for our *Canny Edge
  - Detector* (by means of a Trackbar)
  + Detector* (by means of a Trackbar).
  - Applies the *Canny Detector* and generates a **mask** (bright lines representing the edges
  on a black background).
  - Applies the mask obtained on the original image and display it in a window.
  @@ -85,19 +85,19 @@ Explanation
  Note the following:
  - -# We establish a ratio of lower:upper threshold of 3:1 (with the variable *ratio*)
  + -# We establish a ratio of lower:upper threshold of 3:1 (with the variable *ratio*).
  -# We set the kernel size of \f$3\f$ (for the Sobel operations to be performed internally by the
  - Canny function)
  + Canny function).
  -# We set a maximum value for the lower Threshold of \f$100\f$.
  -# Loads the source image:
  @snippet cpp/tutorial_code/ImgTrans/CannyDetector_Demo.cpp load
  --# Create a matrix of the same type and size of *src* (to be *dst*)
  +-# Create a matrix of the same type and size of *src* (to be *dst*):
  @snippet cpp/tutorial_code/ImgTrans/CannyDetector_Demo.cpp create_mat
  --# Convert the image to grayscale (using the function @ref cv::cvtColor :
  +-# Convert the image to grayscale (using the function @ref cv::cvtColor ):
  @snippet cpp/tutorial_code/ImgTrans/CannyDetector_Demo.cpp convert_to_gray
  --# Create a window to display the results
  +-# Create a window to display the results:
  @snippet cpp/tutorial_code/ImgTrans/CannyDetector_Demo.cpp create_window
  -# Create a Trackbar for the user to enter the lower threshold for our Canny detector:
  @snippet cpp/tutorial_code/ImgTrans/CannyDetector_Demo.cpp create_trackbar
  