How to filter out single/double zero's ?

A = [1	1	1	1	1	1	1	1	1	1	0	1	1	1	1	1	1	1	1	0	0	1	1	1	1	1	1	1	1	1	1	1	0	0	0]

I have vector A and I want to smoothen the vector by changing the single 0's or double 0's to 1's. This means that I want to keep the consecutive zero's when bigger than 2 consecutive.

Is there an easy way to do this without using a for loop?

Thanks

Answer 1

[Fabio Freschi]

% find indices
idx1 = strfind([0 A == 0 0],[0 1 0]);
idx2 = strfind([0 A == 0 0],[0 1 1 0]);

% replace
A(idx1) = 1;
A([idx2(:); idx2(:)+1]) = 1;

[Guillaume]

Note that, while this is a good solution, this usage of strfind with numeric arrays is undocumented. I have suggested to Mathworks to make it documented (or make a function that does the same for numeric vectors), but for now, use at your own perils. It may stop working in future versions.

Answer 2

[Matt J]

B=char([1 A 1]+'0');

B=strrep(B, '101','111');
B=strrep(B,'1001','1111');

B=B(2:end-1)-'0';

Answer 3

[Guillaume]

If you have the Image Processing Toolbox, the easiest is:

newA = imclose(A, [1 1 1])