Want to remove 'noise' from a matrix.

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OliK
OliK 2015-10-8
评论： Image Analyst 2015-10-8
I have a single column matrix with values ranging from around -15 to 50, there's around 19000 values and I wish to remove any values below 20 and set them as 0. This is what I currently have to import the data:
input = xlsread('HiG_67.csv','J:J');
Thanks
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Stephen23
Stephen23 2015-10-8
Do not call your variable input as this is the name of a commonly used inbuilt function input. When you shadow the name of an inbuilt function like this it stops the inbuilt function from working.
For this reason never use the names size, length, input, i, j, cat, length, etc. You can use which to check if a name is already used-

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采纳的回答

Dennie
Dennie 2015-10-8
If input is a non-negative single column then you can use the following simple filter:
FilterValue=20;
input(input<FilterValue)=0;
If there are also negative values that you wish to keep then you can try:
input(abs(input)<FilterValue)=0;
If you only want to filter the positive noise:
filter=input<FilterValue & input>=0;
input(filter))=0;
Dennie
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OliK
OliK 2015-10-8
Is there a way I can do it without Signal Processing Toolbox?
Image Analyst
Image Analyst 2015-10-8
There are peak detectors in the File Exchange.

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更多回答（1 个）

Thorsten
Thorsten 2015-10-8
编辑：Thorsten 2015-10-8
x(x < 20) = 0;
BTW: Please don't call your variable input, it's a Matlab function.

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