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| medfilt1 | See Also |
One-dimensional median filtering.
Syntax
y = medfilt1(x,n) y = medfilt1(x,n,blksz)
Description
y = medfilt1(x,n)
applies an order n, one-dimensional median filter to vector x. y is the same length as x; the function treats the signal as if it is 0 beyond the end points.
For n odd, y(k) is the median of x(k-(n-1)/2:k+(n-1)/2).
For n even, y(k) is the median of x(k-n/2), x(k-(n/2)+1), ..., x(k+(n/2)-1). In this case, medfilt1 sorts the numbers, then takes the average of the (n-1)/2 and ((n-1)/2)+1 elements.
The default for n is 3.
y = medfilt1(x,n,blksz)
uses a for-loop to compute blksz (block size) output samples at a time. Use blksz << length(x) if you are low on memory, since medfilt1 uses a working matrix of size n-by-blksz. By default, blksz = length(x); this is the fastest execution if you have sufficient memory.
If x is a matrix, medfilt1 median filters its columns using
y(:,i) = medfilt1(x(:,i),n,blksz)in a loop over the columns of
x.
See Also
filter |
Filter data with a recursive (IIR) or nonrecursive (FIR) filter. |
medfilt2 |
Two-dimensional median filtering (see Image Processing Toolbox User's Guide). |
median |
Median value (see the online MATLAB Function Reference). |
References
[1] Pratt, W.K. Digital Image Processing. New York: John Wiley & Sons, 1978. Pgs. 330-333.