CODEWITHSUNDEEP
matlabcomputer-visioncontour
Adam893
Adam893

Reputation: 143

Only plot lines of specific length

Below is an image showing a contour plot with areas of interest that have have been connected up by using their centroids. What I want to achieve is that only lines of a certain length are plotted. Currently, every point has a line drawn to every other point.

C=contourf(K{i}); 
[Area,Centroid] = Contour2Area(C);

% This converts any entries that are negative into a positive value
% of the same magnitiude
indices{i} = find( Centroid < 0); 
Centroid(indices{i})=Centroid(indices{i}) * -1; %set all 

% Does the same but for positive (+500)
indices{i} = find( Area > 500); 
Area(indices{i})=0; 

[sortedAreaVal, sortedAreaInd] = sort(Area, 'descend');

maxAreaVals = sortedAreaVal(1:10)';
maxAreaInd = sortedAreaInd(1:10)';

xc=Centroid(1,:); yc=Centroid(2,:);
hold on; plot(xc,yc,'-');

enter image description here

It would be very useful if there was a way of only plotting the lines that fall below a specific threshold. The next step will be to label and measure each line. Thanks in advance for your time.

Upvotes: 0

Views: 276

Answers (1)

pragmatist1
pragmatist1

Reputation: 919

If xc and yc are the x and y coordinates of the centroids, then you could do something like this:

sqrt(sum(diff([x,y],1).^2,2))

What this does is take the difference between successive [x,y] data points, then calculate the Euclidean distance between them. You then have all the information you need to select the ones you want and label the lengths.

One thing though, this will only compute distances between successive centroids. I wrote it this way because it appears that's what you're trying to do above. If you are interested in finding out the distances between all centroids, you would have to loop through and compute the distances. Something along the lines of:

for i=1:length(xc)-1
    for j=i+1:length(xc)
       % distance calculation here...

Hope this helps.

Upvotes: 2

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