Canny Edge Detection Steps

As promised in my previous post and in response to a comment  , here is a step by step explanation of the Canny Edge Detector. I have some images from a previous post available here.

Firstly we need to apply a Gaussian Point Spread Function (PSF) to our image. This will make the image seem slightly blurry. Increasing the width of the filter will of course increase the blurriness of the image. A wider filter tends to cause the Canny Edge detector to detect longer smoother lines while a narrow filter allows it to find shorter lines.