Loop in a array

Question

Emmanuelle 2012-11-26

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/54796-loop-in-a-array

Hi,

I have a question. I have an image with three bands. How can I apply a loop for do an operation to all the pixels?

image1=imread('image_1.tif'); %I've load the image. Has a length of 4x4x3
band1a= image_1(:,:,1);
band2a= image_1( :,:,2);
band3b= image_1(:,:,3);
for i = 1:numel(band1b)
(...) this is the part of the operation
output= ?

Thanks a lot in advance,

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Emmanuelle 2012-11-26

编辑：Emmanuelle 2012-11-27

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I know it would be a bit confusing...

   image1=imread('image_1.tif'); 
   band1a= image1(:,:,1);
   band2a= image1(:,:,2);
   band3b= image1(:,:,3);
   for i = 1:numel(band1b) 
   ma = zeros(100,1);
   ma(10) = banda1b(i);
   end 
  for i = 1:numel(band2b)
   ma(25) = banda2b(i);
   end 
  for i = 1:numel(band3b)
   ma(50) = band3b(i);
   end 
vec1= [10, 25, 50]';
 pos1= ma(10);
 pos2= ma(25);
 pos3= ma(50);
 vec2= [pos1 pos2 pos3];
 t= 0:100;
 xi= 0:1:100;
 interplan= interp1(vec1,vec2,t,'spline');
   sp1_a= spb1y.*interplan; %I've defined sp1by before
   sp1_b= sp1_a./spsum1;
   sp2_a= spb2y.*interplan;
   sp2_b= sp2_a./spsum2;
   sp3_a= spb3y.*interplan;
   sp3_b= spout3_a./spsum3;
    spout1_c= sum(spout1_b);
   spout2_c= sum(spout1_b);
   spout3_c= sum(spout1_b);

I know it could be something confusing but what I want is to get this last three values (spout1_c, spout2_c and spout3_c) for every pixel, in every band.

Hope I've explain this well!

Emmanuelle 2012-11-27

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The main problem is the following part because in an assignment A(I) = B, the number of elements in B must be the same but, I need to do it because it's important the 'position' in the interpolation.

   for i = 1:numel(band1b) 
   ma = zeros(100,1);
   ma(10) = banda1b(i);
   end 
  for i = 1:numel(band2b)
   ma(25) = banda2b(i);
   end 
  for i = 1:numel(band3b)
   ma(50) = band3b(i);
   end

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Answer 1

Image Analyst 2012-11-26

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https://ww2.mathworks.cn/matlabcentral/answers/54796-loop-in-a-array#answer_66536

What is image_1? All you have shown up until that point is image1, which is a different variable.

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Image Analyst 2012-11-27

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Regarding "I know it could be something confusing but what I want is to get this last three values (spout1_c, spout2_c and spout3_c) for every pixel, in every band." How about this:

image1(:, :, 1) = spout1_a;
image1(:, :, 2) = spout1_b;
image1(:, :, 3) = spout1_c;

Emmanuelle 2012-11-27

在 MATLAB Online 中打开

Thanks Image analyst! :) I've solved the problem starting the code like this:

for row= 1: nrows
      for col= 1: ncols
        for band= 1: nband

But now I don't know how it's possible to copy correctly the output. I've created my output matrix like this:

output= zeros(1200, 1202, 3);

And I want to copy the spout1_a to the first band (band1a), spout1_b to the second.... I'm trying with that but I get the following error: " Conversion to double from cell is not possible."

output(:,:,1)= {spout1_c}

Thanks!!

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