| Description |
This function finds the 'first' pixel in an image along a dimension. This is somewhat like measuring from the top row of an image towards the bottom row of the image, and recording the first collision with an "on" pixel.
%FIND_NDIM Finds first/last nonzero element indices along a dimension.
% I = FIND_NDIM(BW,DIM) returns the subscripts of the first nonzero elements
% of BW along the dimension DIM. Output I will contain zeros in element
% locations where no nonzero elements were found
%
% I = FIND_NDIM(BW,DIM,'first) is the same as I = FIND_NDIM(BW,DIM).
%
% I = FIND_NDIM(BW,DIM,'last') returns the subscripts of the last nonzero elements
% of BW along the dimension DIM.
%
% Example 1:
% If X = [0 1 0
% 1 1 0]
%
% then find_ndim(X,1) is [2 1 0] and find_ndim(X,2) is [2
% 1];
% Example 2:
% I = imread('rice.png');
% greyIm = imadjust(I - imopen(I,strel('disk',15)));
% BW = imclearborder(bwareaopen(im2bw(greyIm, graythresh(greyIm)), 50));
% topMostOnInds = find_ndim(BW, 1, 'first');
% rightMostOnInds = find_ndim(BW, 2, 'last');
% figure, imshow(BW), hold on
% plot(1:size(BW,2), topMostOnInds, 'r.')
% plot(rightMostOnInds, 1:size(BW,1), '.b')
A discussion of how this came about is at:
http://www.mathworks.com/matlabcentral/newsreader/view_thread/244823 |
