Selecting data from a matrix using a mask

[samsetch]

Hello I am new to Octave but am trying to use it as a tool to analyze paired
matrices that are created as an output from a MetriPol microscope system.

The output given is two  1024x1360 matricies, one containing vales from
0-180 (angles) the other 0-0.8 (sindelta)

The idea is to create a mask from the angle data with a threshold of say 100
degrees. I then aim to lables the points less than 100 degrees as 1 the rest
0's. I then want to use this mask to analyze the sindelta matrix and pick
out the points that relate to these 1's.

After discussion with a colleague who was experienced in MATLAB he came up
with this code:

% runs a masking of sindelta vaules given a orientation threshold

% x is the orientation data 0-180 range
x
threshold=100;
[row,col]=find(x>threshold);

lengthrow=length(row);

% looping through all x,y coords that are >100 and zero-ing them.
Thresholding data

for t=1:lengthrow

x(row(t),col(t))=0;

end

x=(x>0);

figure(1)
image(x)

[row1,col1]=find(x==1);

% load data sindelta call it y

lengthrow1=length(row1);


sizex=size(x);
yselectregions=zeros(sizex(1),sizex(2))

% making image containing only sindelta values that match with the
orientation %data<threshol

for t=1:lengthrow
yselectregions(row1(t),col1(t))=y(row1(t),col1(t));

end

figure(2)
image(yselectregions)


However this is just creating a matrix of 0's

Any help with this problem would be greatly appreciated.

Thanks

Sam 

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