MATLAB: How to store the output of several of structures produced from “bwconncomp”

pixelidxlist field

I have an image and divide this image into blocks, I apply connected component function called "bwconncomp" to each block, I need to store the PixelIdxList field of the structure produced from function "bwconncomp" for each block?

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variablename = {structurename.PixelIdxList};

You need the cell array because the entries can be different sizes.

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MATLAB: How can I access to pixels of objects produced by connected componenets function

bwconncomp only returns the indices of the non-zero pixels.

bwconncomp returns a structure. The PixelIdxList field of the structure is a cell array. Each element of the cell array is a vector of linear indices. You can use ind2sub() if you want to turn those linear indices into row and column subscripts.

Example:

bw = rand(20,30) > 0.3;      %sample data
CC = bwconncomp(bw);
idxlists = CC.PixelIDxList;
first_component_idx = idxlists{1};
%now some manipulation
%notice we did not use bw(R(1:2), C(1:2)) as that would usually access 2 x 2 pixels
[R, C] = ind2sub(size(bw), first_components_idx);
bw(R(1), C(1)) = 0;
bw(R(2), C(2)) = 0;
%alternate manipulation equivalent to the above
bw(first_components_idx(1:2)) = 0;

MATLAB: Question related to Image analysis Functions: bwconncomp and regionprops

The number of connected components from bwlabel() or bwconncomp() will match the number of structures in the structure array returned by regionprops. Each blob has one structure,and that structure may have as many members as properties you requested. For example if you asked for area and perimeter, of 100 blobs, then you'd have an array of 100 structures, with each structure having 2 members (fields).

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MATLAB: How can I access to pixels of objects produced by connected componenets function

MATLAB: Question related to Image analysis Functions: bwconncomp and regionprops

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