How to get INTENSITY along a spcific curve?

5 次查看（过去 30 天）

显示更早的评论

Steven 2014-1-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/112348-how-to-get-intensity-along-a-spcific-curve

评论： Image Analyst 2021-6-30

采纳的回答： Ashish Uthama

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.

Shall I do so for the grayscale image or the binary one?

Thanks so much

Steven

采纳的回答

Ashish Uthama 2014-1-14

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/112348-how-to-get-intensity-along-a-spcific-curve#answer_120849

在 MATLAB Online 中打开

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)

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.

george korris 2021-4-1

yeah youre write. thanks for your time!

have a nice day!

请先登录，再进行评论。

更多回答（1 个）

Image Analyst 2014-1-14

7
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/112348-how-to-get-intensity-along-a-spcific-curve#answer_120867

在 MATLAB Online 中打开

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);