MATLAB: Contrast image processing ultrasound

drawrectangleImage Processing Toolboxroistudent

Hi guys we are calculating the contrast of a cyst inside an ultrasound image. With the code we select the square ROI manually, but then we also need a ROI of the same size to calculate the background. Then extract from the medium cyst the level of gray and variance. Can you help us?

im= imread('_258.tif');

imshow(im);

c_im=imcrop(im);

c_im=rgb2gray(c_im);

imshow(c_im);

xmed=mean2(c_im);

xstd=std2(c_im);

Best Answer

ALESSIA:

Try this little demo:

grayImage = imread('Cameraman.tif');
subplot(2, 2, 1);
imshow(grayImage);
g = gcf;
g.WindowState = 'maximized';
title('Gray Scale Image', 'FontSize', fontSize);
uiwait(helpdlg('Click and drag to draw the inner circular region.'));
roi = drawcircle('Color', 'red')
innerMask = roi.createMask;
innerXY = roi.Vertices;
uiwait(helpdlg('Click and drag to draw the outer circular region.'));
roi = drawcircle('Color', 'green')
outerMask = roi.createMask;
outerXY = roi.Vertices;
% Exclude the inner mask from the outer mask.
outerMask = xor(outerMask, innerMask);
% Get the mean in the circles.
innerMeanGL = mean(grayImage(innerMask))
outerMeanGL = mean(grayImage(outerMask))
subplot(2, 2, 2);
imshow(innerMask);
title('Inner Mask Image', 'FontSize', fontSize);
subplot(2, 2, 3);
imshow(outerMask);
title('Outer Mask Image', 'FontSize', fontSize);
subplot(2, 2, 4);
imshow(grayImage);
hold on;
% Draw the circles.
plot(innerXY(:, 1), innerXY(:, 2), 'r-', 'LineWidth', 2);
plot(outerXY(:, 1), outerXY(:, 2), 'g-', 'LineWidth', 2);
caption = sprintf('Inner mean GL = %.3f, Outer mean GL = %.3f', innerMeanGL, outerMeanGL);
title(caption, 'FontSize', fontSize);

If this answers your question, could you "Accept this answer"? Thanks in advance.

Related Solutions

MATLAB: Crop dark area and display the face only

Convert to grayscale and then threshold and find the bounding box

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
imtool close all;  % Close all imtool figures.
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;
% Read in the color image.
folder = pwd;
baseFileName = 'm2.bmp';
% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);
if ~exist(fullFileName, 'file')
  % Didn't find it there.  Check the search path for it.
  fullFileName = baseFileName; % No path this time.
  if ~exist(fullFileName, 'file')
    % Still didn't find it.  Alert user.
    errorMessage = sprintf('Error: %s does not exist.', fullFileName);
    uiwait(warndlg(errorMessage));
    return;
  end
end
rgbImage = imread(fullFileName);
% Get the dimensions of the image.  numberOfColorBands should be = 3.
[rows, columns, numberOfColorBands] = size(rgbImage);
% Display the original color image.
subplot(2, 3, 1);
imshow(rgbImage, []);
axis on;
title('Original Color Image', 'FontSize', fontSize);
drawnow;
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Histogram the red channel, but there is a huge spike at 255 so let's not count those.
subplot(2, 3, 2);
grayImage = rgb2gray(rgbImage);
imshow(grayImage, []);
title('Gray Scale version', 'FontSize', fontSize);
subplot(2, 3, 3);
histogram(grayImage(grayImage<255))
grid on;
title('Histogram of Gray Scale Image', 'FontSize', fontSize);
someThresholdValue = 150;
binaryImage = grayImage > someThresholdValue;
% Take largest blob
binaryImage = bwareafilt(binaryImage, 1);
subplot(2, 3, 4);
imshow(binaryImage);
grid on;
title('Binary Image', 'FontSize', fontSize);
% Label the binary image.
labeledImage = bwlabel(binaryImage);
props = regionprops(labeledImage, 'BoundingBox');
bbox = props.BoundingBox
croppedImageRGB = imcrop(rgbImage, bbox);
subplot(2, 3, 5);
imshow(croppedImageRGB);
grid on;
title('Cropped RGB Image', 'FontSize', fontSize);
% Gray scale version of cropped image
croppedImageGray = imcrop(grayImage, bbox);
subplot(2, 3, 6);
imshow(croppedImageGray);
grid on;
title('Cropped Gray Scale Image', 'FontSize', fontSize);

MATLAB: Draw pixels within threshold interval

Try this demo. It uses the thresholds to get a mask than erases outside that mask. Then it makes a colormap and applies it only within the threshold range. Adapt as needed.

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 22;
%--------------------------------------------------------------------------------------------------------





%    READ IN IMAGE
folder = pwd;
baseFileName = 'cameraman.tif';
grayImage = imread(baseFileName);
% Get the dimensions of the image.
% numberOfColorChannels should be = 1 for a gray scale image, and 3 for an RGB color image.
[rows, columns, numberOfColorChannels] = size(grayImage)
if numberOfColorChannels > 1
	% It's not really gray scale like we expected - it's color.
	% Use weighted sum of ALL channels to create a gray scale image.
	grayImage = rgb2gray(grayImage);
	% ALTERNATE METHOD: Convert it to gray scale by taking only the green channel,
	% which in a typical snapshot will be the least noisy channel.
	% grayImage = grayImage(:, :, 2); % Take green channel.
end
%--------------------------------------------------------------------------------------------------------
% Display the image with the original, linear colormap.
subplot(2, 2, 1);
cmap = jet(256);
imshow(grayImage, 'Colormap', cmap);
axis('on', 'image');
title('Original Color Map', 'FontSize', fontSize, 'Interpreter', 'None');
impixelinfo;
colorbar;
hFig = gcf;
hFig.WindowState = 'maximized'; % May not work in earlier versions of MATLAB.
drawnow;
set(gca,'ColorScale','log')
%--------------------------------------------------------------------------------------------------------
% Show the histogram:
subplot(2, 2, 2);
imhist(grayImage);
grid on;
title('Histogram', 'FontSize', fontSize, 'Interpreter', 'None');
minGL = 150;
maxGL = 190;
xline(minGL, 'Color', 'r', 'LineWidth', 2);
xline(maxGL, 'Color', 'r', 'LineWidth', 2);
%--------------------------------------------------------------------------------------------------------
% BINARIZE THE IMAGE
mask = grayImage >= minGL & grayImage <= maxGL;
%--------------------------------------------------------------------------------------------------------
% Display the mask.
subplot(2, 2, 3);
imshow(mask);
axis('on', 'image');
title('Mask', 'FontSize', fontSize, 'Interpreter', 'None');
impixelinfo;
colorbar;
drawnow;
%--------------------------------------------------------------------------------------------------------
% Apply the mask
maskedImage = grayImage; % Initialize
maskedImage(~mask) = 0; % Erase outside of mask
subplot(2, 2, 4);
imshow(maskedImage, 'Colormap', cmap);
axis('on', 'image');
caption = sprintf('Masked Image with color map applied between %d and %d', minGL, maxGL);
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
impixelinfo;
colorbar;
caxis([minGL, maxGL]);
drawnow;

Best Answer

Related Solutions

MATLAB: Crop dark area and display the face only

MATLAB: Draw pixels within threshold interval

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