MATLAB: Find nearest neighbors of a point

image analysis

Hi!

The green points in the figure are my reference points. I want to find the k nearest neighbors of red points to each green point.

I have the coordinates of all points.

Any suggestions?

Regards,

Anders Holmberg

Best Answer

Refer to the documentation of knnsearch & Nearest Neighbors.

Related Solutions

MATLAB: Finding K nearest neighbors

The ‘knnsearch’ function was introduced in 2010a. If you have ‘pdist’ (see http://www.mathworks.com/help//stats/pdist.html ) or ‘pdist2’ (see http://www.mathworks.com/help//stats/pdist2.html ), you can probably generate your own version of ‘knnsearch’. If you have to write your own cosine distance metric as well, you can find the expression on those pages. The ‘sort’ function (with two output arguments) may also be useful.

MATLAB: Interpolation Nearest Neighbor

The description of your problem is very lean. Posting a copy of the resulting image would be a good idea.

Please try this:

factor = 1.5;
for j = 1:4
  disp(round(1+(j-1)*fator));
end 
% Result: 1  3  4  6

This means, that e.g. the 2nd row and column of the created image do not get any value and have therefore the value 0. A solution would be to run the loopover the coordinates of the output image and divide the coordinates of the input image by "factor". The speed will be dramatically higher, if you pre-allocate the output arry:

imagem2 = zeros(round(lin*factor), round(col*factor), 3)

But much more efficient is using INTERP2 or IMRESIZE.

Best Answer

Related Solutions

MATLAB: Finding K nearest neighbors

MATLAB: Interpolation Nearest Neighbor

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