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Entering RGB values from a matrix

Asked by Ali Afshar Dodson on 22 Aug 2014 at 15:43
Latest activity Edited by dpb on 24 Aug 2014 at 15:35

Hi all,

I'm trying to plot an rgb matrix onto co-ordinates defined by Seed0Orange and Seed0Blue. However whilst the results work for i=1 when I try and cycle through the matrix I get "Error using plot Color value contains NaN, or element out of range 0.0 <= value <= 1.0". However there are no elements outside of the range or any NaNs. Any help would be much appreciated

for i = 1:5000
plot(Seed0Orange(1,i), Seed0Blue(1,i), 'kx','MarkerEdgeColor',[datanew(i,1) datanew(i,2) datanew(i,3)],...
'MarkerFaceColor',[datanew(i,1) datanew(i,2) datanew(i,3)]);
end

7 Comments

dpb on 23 Aug 2014 at 14:21

About only other thought I'd have at this point would be floating point rounding...what do

any(datamew>1)
any(datamew<0)

return?

Ali Afshar Dodson on 24 Aug 2014 at 10:56

Looks like that might be the problem.

 any(datanew>1)
ans =
       1     0     1
EDU>> any(datanew<1)
ans =
       1     1     1
dpb on 24 Aug 2014 at 13:24

How was the array datanew generated?

If result of a floating point computation, it's always possible for the above to occur. To fix the issue can use several alternatives, probably the simplest is simply to clip the result on the upper bound by

datanew=min(datanew,1);

To find which one(s) are the issue use find -- perhaps there's a slight error in the computation or another reason for the problem that you want to correct other than by the above; can't tell that from here, of course.

The second test above was intended to be <0 but that's not the case as I'd neglected that the previous result of min was shown to be 0.05. The result of any<1 is as expected of course, what would show the problem would be all<1 which will show 0 1 0, the complement of any>1.

Ali Afshar Dodson

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1 Answer

Answer by Image Analyst on 24 Aug 2014 at 14:56

(Regarding dpb's comment) You can find out which ones are above or below via the second return argument of min() or max(). Why not just clip

datanew(datanew>1)=1;
datanew(datanew<0)=0;

before you enter the for loop and pass it into plot()?

I know I asked for your data before (above in the comments) but I haven't seen it yet, or any code as to how you created it. How was your colormap, datanew, generated?

0 Comments

Image Analyst

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