Morphological operation on 1-D signal (ECG)

I'm a bit confused about the morphological operation erosion and dialtation, and their derivation opening and closing.

Specifically, I am referring to the functions present in the Image Processing Toolbox:

• imerode
• imdilate
• imopen
• imclose

I was told that these operationd are not adequate for a 1-D signal and would require additional operationd to use them with a 1-D signal.

I have tried anyway to use the above functions and the results obtained completely reflect the expected ones (I am using the morphological operators to filter an ecg signal).

So my question is: is it right the fact that I can't use the above functions for a 1-D signal and that to make them work I need to apply some methodology first?

And another topic, if I want to write my own functions for the erosion and the dilatation operation for a 1-D signal (an ecg signal), where can I information on the two methods?

Answer 1

[Image Analyst]

What you were told is wrong. They do work for 1-D vectors. Look:

vector1D = randi(9, 1, 31, 'uint8')

vector1D = 1×31

5 2 3 7 6 8 2 4 7 6 7 9 1 5 9 5 3 4 8 6 5 9 8 4 9 8 7 2 9 8

v = imdilate(vector1D, true(1, 3))

v = 1×31

5 5 7 7 8 8 8 7 7 7 9 9 9 9 9 9 5 8 8 8 9 9 9 9 9 9 8 9 9 9

Alternatively, there are some base MATLAB functions that are equivalent, like movmax and movmin.