GaussianBlur and Canny functions


for OpenCV C++, in the YouTube video tutorial

GaussianBlur(img, img_man, Size(3,3),3,0);

In regards to this code, what does Size() exactly do and what do the last two arguments (the values are 3 and 0) even mean?

And in regards to

Canny(img_man, img_canny, 50, 150);

What do the last two arguments mean? And how come I have to blur the image a bit in order to use this edge detection tool?

I think that all answers to your question are in gaussianblur doc

|ksize|Gaussian kernel size. ksize.width and ksize.height can differ but they both must be positive and odd. Or, they can be zero’s and then they are computed from sigma.|
|sigmaX|Gaussian kernel standard deviation in X direction.|
|sigmaY|Gaussian kernel standard deviation in Y direction; if sigmaY is zero, it is set to be equal to sigmaX, if both sigmas are zeros, they are computed from ksize.width and ksize.height, respectively (see getGaussianKernel for details); to fully control the result regardless of possible future modifications of all this semantics, it is recommended to specify all of ksize, sigmaX, and sigmaY.|

You can read this tutorial too about smoothing images

Feel free to ask question about content of this document

Hi mate,

I read the document and I have no idea what is signma nor what does it do, do you know what it means mate?

And I have no idea what this means either mate :frowning: