Hue value of a specific pixel
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Tasneem Al-Tmimi
on 1 Nov 2017
Commented: Image Analyst
on 6 Nov 2017
I have a segmented image I, I have used labeling to find the segmented objects, and using region props function I have extracted the centroid pixel value.
My question is:
Is there a way to find the hue value of this specific pixel value in my case the centroid ?
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Accepted Answer
Image Analyst
on 1 Nov 2017
Yes
hsvValues = rgb2hsv(rgbValues);
hueValue = hsvValues(:,:,1);
5 Comments
Image Analyst
on 2 Nov 2017
Centroid will be a floating point number with fractional values, so you need to round it to the nearest integers.
More Answers (1)
Image Analyst
on 4 Nov 2017
Why not just get the mean hue of the whole thing?
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 = 25;
%===============================================================================
% Get the name of the image the user wants to use.
baseFileName = 'IMG_7379_2.jpg';
% Get the full filename, with path prepended.
folder = pwd
fullFileName = fullfile(folder, baseFileName);
% Check if file exists.
if ~exist(fullFileName, 'file')
% The file doesn't exist -- didn't find it there in that folder.
% Check the entire search path (other folders) for the file by stripping off the folder.
fullFileNameOnSearchPath = baseFileName; % No path this time.
if ~exist(fullFileNameOnSearchPath, 'file')
% Still didn't find it. Alert user.
errorMessage = sprintf('Error: %s does not exist in the search path folders.', fullFileName);
uiwait(warndlg(errorMessage));
return;
end
end
%===============================================================================
% Read in demo image.
rgbImage = imread(fullFileName);
% Get the dimensions of the image.
[rows, columns, numberOfColorChannels] = size(rgbImage);
% Display the original image.
subplot(1, 2, 1);
imshow(rgbImage, []);
axis on;
caption = sprintf('Original Color Image, %s', baseFileName);
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
hp = impixelinfo();
% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0.05 1 0.95]);
% Get rid of tool bar and pulldown menus that are along top of figure.
% set(gcf, 'Toolbar', 'none', 'Menu', 'none');
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off')
drawnow;
hp = impixelinfo(); % Set up status line to see values when you mouse over the image.
% Create the region of interest (ROI)
Igray = rgb2gray(rgbImage);
binaryImage = ~imbinarize(Igray);
% Take largest 2 blobs only
binaryImage = bwareafilt(binaryImage, 2);
% Fill them to get rid of noise.
binaryImage = imfill(binaryImage, 'holes');
% Display the mask image.
subplot(1, 2, 2);
imshow(binaryImage, []);
axis on;
caption = sprintf('Binary Image');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
hp = impixelinfo();
drawnow;
% Convert rgb to hsv
hsvImage = rgb2hsv(rgbImage);
hueImage = hsvImage(:, :, 1);
% Compute the mean hue within the mask:
meanHue = mean(hueImage(binaryImage))
message = sprintf('The mean hue angle is %f', meanHue);
uiwait(helpdlg(message));
% Measure properties of the blobs.
% props = regionprops(binaryImage, 'Centroid');
5 Comments
Image Analyst
on 6 Nov 2017
No, the square root of a squared and b squared, like I said. LAB color space should work for any color.
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