How to get INTENSITY along a spcific curve?
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Hi.
How can I get the intensity along a specific curve?
I mean for the following image, I want the intensity along the red circle. How to do so?
The original image is only the grayscale one and I have drawn the red one myself, so I know its data.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/155065/image.jpeg)
Shall I do so for the grayscale image or the binary one?
Thanks so much
Steven
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采纳的回答
Ashish Uthama
2014-1-14
You could try using improfile, it will let you draw the cirle and then return the values along the profile.
Air code:
imshow(yourRawGrayImage)
% number of points you want to sample the profile with
N = 100;
profileValues = improfile(N)
10 个评论
Image Analyst
2021-4-1
Correct, I don't. It's just the intensity around the ellipse. Why do you think the spatial frequencies of that are meaningful? Maybe they're just more or less constant, perhaps with a little noise - basically the surrounding gray level of the blob. What information do you want?
Please start your own question with your own image and code attached.
更多回答(1 个)
Image Analyst
2014-1-14
Try this code:
clc; % Clear the command window.
clear; % Erase all existing variables. Or clearvars if you want.
workspace; % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 24;
% Read in image
grayImage = imread('tire.tif');
% manually create a circle
subplot(2,2,1);
imshow(grayImage);
title('Original Grayscale Image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Let user create ellipse.
h = imellipse();
% Create a mask out of it
mask = createMask(h);
subplot(2,2,2);
imshow(mask);
title('Mask Image', 'FontSize', fontSize);
% Find boudnaries and plot over original grayscale image.
boundaries = bwboundaries(mask);
numberOfBoundaries = size(boundaries, 1);
subplot(2,2,1);
hold on;
thisBoundary = boundaries{1};
x = thisBoundary(:,2);
y = thisBoundary(:,1);
plot(x, y, 'g', 'LineWidth', 2);
hold off;
% extract all pixels along this profile
for k = 1 : length(x)
profile(k) = grayImage(y(k), x(k)); % logical indexing
end
subplot(2,2, 3);
plot(profile);
grid on;
title('Profile', 'FontSize', fontSize);
xlabel('Distance', 'FontSize', fontSize);
ylabel('Gray Level', 'FontSize', fontSize);
12 个评论
Image Analyst
2021-6-30
@Anna Schoonen, please post this in a thread of your own rather than using Steven's 7 year old question.
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