Read LiDar/LAS file in matlab.

January 11, 2010

Below is the c code for reading LiDar/LAS file into matlab. To compile the code, simply use
mex LASReader.cpp

The code reads the points coordinates only. Please see the code for details.

For details of LiDar file format, please visit this link.

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Convert EPS to PDF: problem of bounding box

June 17, 2009

When you save a multiple plots/subfigures figure as an eps file in matlab, the bounding box might not be properly defined. People who use pdflatex need to convert EPS to PDF. The undefined bounding box will cause problems if you use epstopdf to convert EPS to PDF. This problem is shown in the first row in the picture below. The top-left figure is the eps file without properly defined bounding box. Because of this, epstopdf simply printed a letter size pdf file that only contains part of the figure as shown in the top-right figure. You can try to use the option –exact

epstopdf --exact bad.eps

It will probably generate an warning msg like “Warning: BoundingBox not found!” and the resulting pdf is still wrong. One way to fix this problem is to use epstool

epstool --copy --bbox bad.eps --output good.eps

The bbox option tells epstool to generate a (correct) bounding box for the eps file. With a correctly defined bounding box, you can easily convert an eps file to a pdf file.

epstopdf --exact good.eps

The results are shown in the 2nd row of the picture below. epstopdf generated an pdf file in the same size as the eps file.
pic


The index of the largest element in a 2D array in matlab

November 12, 2008

[v,ind]=max(X);
[v1,ind1]=max(max(X));
disp(['The largest element in X is' num2str(v1) ' at (' num2str(ind(ind1)) ',' num2str(ind1) ')']);


Displaying a sequence of images like video in matlab

July 9, 2008

images is an array of dim imageHeight x imageWidth x frameNumber


for i = 1:size(images,3)
    imshow(images(:,:,i));
    title(['frame# ' num2str(i)]);
    drawnow; %// this is why it works
end