move a 3*3 window on a binary image

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atefeh gh 2014-9-3

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评论： Image Analyst 2014-9-5

hi I have a 3*3 window and a binary image..I want to move this window on this image... how can do this? thanks

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David Young 2014-9-3

What operation do you want to carry out?

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Image Analyst 2014-9-3

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Try imfilter(), conv2(), or nlfilter(), or possibly blockproc(). That's about all I can say until you provide more information.

No it's definitely not a low pass filter, that's a linear filter by the way. What he's asking for is a non-linear filter (median and dilation are some examples of non-linear filters). He wants to ignore the middle column and see if a pixel in the left column matches its partner on the right column (or maybe any pixel in the right column, that's what I'm asking him to tell us). So if you had two lines separated by a space (like edges of a bronchial tube), then it would fill in the space between the edges. It would not affect things outside the tube. Of course this is very dependent on window width and tube width. For example it would not work on edges separated by 3 or 4 columns of space. You'd have to use a bigger window for that and check more pixels. I'm wondering if the window size needs to be adjusted depending on the side of the tubes. Plus it would only work for vertical tubes, not horizontal ones.

I think there may be a way to construct this non-linear filter from two passes of a convolution with special kernels and thresholding but we need a better definition of how the left and right are compared to see how many kernels we'd need and what the threshold values need to be. But it wouldn't be a straight moving average (blurring).

atefeh gh 2014-9-5

在 MATLAB Online 中打开

so is there any Differences between what you say and this:

 t1=1/9*[1 1 1;1 1 1;1 1 1];
 t2=imfilter(binaryimage,t1);
like that Joseph said...am I right or not?
thanks Image Analyst

Image Analyst 2014-9-5

I think that should be the same. Sometimes there are weird things about keeping classes the same so you'd need to check that. For example t2 mgiht be uint8 instead of double and thus not show fractional numbers but just round to 0 and 1. If that happens, just cast to double before sending in to imfilter.

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atefeh gh 2014-9-3

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thanks David and Image Analyst I think I can do this by blockproc...I saw in help this: B = blockproc(A,[M N],FUN)

I want to explain the work that I want to do: I should apply 3*3 window based on this: if pexels located on two oposite sides of window have similar logical values(e.g,zero) all pixels covered by this window will be converted to that logical value(e.g,zero)

I want to know Is there any function can halep me to apply my work?? I hope I could explain my work to you.. Thanks in advance