0 个投票

Hi everyone,
here i want to get pixel intensity out of a 512*512 image.
i wrote two for loops, but in the end in matrix 'intensityValue', l got only the last set of data.
the background is to get the coordinates from x and y. corx and cory are 41*75 matrices.
Thanks !
fluo = imread('fluo0020.tif');
% imshow(fluo);
corx=[];
cory=[];
intensityValue=[];
for i=1:length(coordinate)
A = [coordinate ; coordinate(1,:)] ;
if mod(i, 2) == 1
x= int16(A(:,i));
y= int16(A(:,(i+1)));
corx=[corx,x];
cory=[cory,y];
end
% scatter(x,y);
% line(x,y);
% hold all
end
for ttt=1:length(x)
xc=x(ttt,:);
xy=y(ttt,:);
inten=fluo(xc,yc);
intensityValue =[intensityValue;inten];
end

3 个评论
显示 1更早的评论 隐藏 1更早的评论

Ameer Hamza
Ameer Hamza 2020-3-6
I don't fully understand the logic of this code, however, shouldn't the last part be,
for ttt=1:length(corx)
xc=corx(ttt,:);
xy=cory(ttt,:);
inten=fluo(xc,yc);
intensityValue =[intensityValue;inten];
end
yunwei hu
yunwei hu 2020-3-6
i am still new to write the code.... it's true there not so much logic..
what l tried to get is the same corresponding values(the same row and column) from corx and cory, which l have uploaded. They are actually the x and y coordinates.
And from the two vuales, i get the intensity from the image.
the final intensityValue i expected is a 42*75 matrix
Thank you for your reply!
Ameer Hamza
Ameer Hamza 2020-3-6
Please check the one-liner in the answer to directly extract the value instead of writing a for loop.

请先登录，再进行评论。

请先登录，再回答此问题。

 采纳的回答

Ameer Hamza
Ameer Hamza 2020-3-6
编辑：Ameer Hamza 2020-3-6

0 个投票

You are directly use corx and cory variables to extract values from the matrix instead of the second for loop in your code.
intensityValue = fluo(sub2ind(size(fluo), cory, corx)); % cory is the row number and corx is the column number

7 个评论
显示 5更早的评论 隐藏 5更早的评论

yunwei hu
yunwei hu 2020-3-6
Hi Ameer,
there is an error "Out of range subscript."
you are right about that l am extracting values form two matrices.
but l am not sure about the row number and column number, since both corx and cory are the matrix have the same number of rows and columns, as l uppolded before.
Ameer Hamza
Ameer Hamza 2020-3-6
But the corx and cory are extracting the values from fluo. Do the elements of corx denotes the row number of the pixel in flou or the column number?
I suspect that, if you got out of bound error, the following might be the correct.
intensityValue = fluo(sub2ind(size(fluo), corx, cory));
yunwei hu
yunwei hu 2020-3-6
corx is the row number.
but l tried this code as well.
the same error occured.
Could be that the number in corx or cory exceed 512?
Since i turned to all into int16, maybe this could be the problem?
Ameer Hamza
Ameer Hamza 2020-3-6
This depends on the resolution of you image file. The number in corx and cory should not exceed the image dimensions.
If possible share the image file and the value of variable coordinate in a mat file.
yunwei hu
yunwei hu 2020-3-6
i share the files
they should not exceed l suppose.
Ameer Hamza
Ameer Hamza 2020-3-6
As you can see, the image dimension is 512x512, and some elements of corx and cory are higher than 512. Therefore it is throwing an error. I guess that there is some issue in the calculation of the corx and cory in the first loop.
yunwei hu
yunwei hu 2020-3-6
Now i see.
i would check the data again.
thank you so much for your help!

请先登录，再进行评论。

更多回答（0 个）

类别

在 帮助中心 和 File Exchange 中查找有关 Loops and Conditional Statements 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by