How to find out what this code does

This code pertains to image processing - line parameters Hough transform. Not sure what the third line does.

f=zeros(128,128); 
f(32:96,32:96)=255;
[image,t3]=edge(f, 'canny', [0.04 0.10], 1)

[Voss]

https://www.mathworks.com/help/images/ref/edge.html

[Ken]

Thanks. The way I see it:

t3 = threshOut

[0.04 0.10]=threshold

1 is ?

[Voss]

The 1 represents "sigma — Standard deviation of filter"

[Ken]

Sorry for another - what exactly is TheshOut?

[Steven Lord]

In general, if you're not sure what an input or output argument for a function represents click on its name (which should be a hyperlink) in the Description section on its documentation page. That will jump to the entry in the Input Arguments or Output Arguments sections where it is described.

For this particular function, if you're not sure how the threshold value is used in the computation look at the Algorithms section for a brief description of the algorithm or the papers cited in the References section for a more in-depth description.