MATLAB: HOW TO GET CENTRAL PIXEL

image processing

how to get the central non-zero valued pixel in a row of an image. My aim is to get the principal axis of an image. I already operate different morphologocal operation to get this. I got the thin axis with single non-zero vale in some row BUT not all row. In some row there are multiple number of non-zer valed pixel.

so i want to extract the central pixel (non-zero valued) in each row.

HELP ME.

Best Answer

[~, central_pixel_idx] = min( abs( bsxfun(@times, logical(YourGrayImage), 1:size(YourGrayImage,2)) - size(YourGrayImage,2)/2)) );

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MATLAB: How to code the total pixels number and white pixels and black area pixels number

Try this:

[baseName, folder]=uigetfile('*.png','select an image');
fullFileName = fullfile(folder, baseName);
grayImage = imread(fullFileName);
% 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.
imshow(grayImage, []);
title('Original Grayscale Image', 'FontSize', 20, 'Interpreter', 'None');
% Assuming grayImage is a binary image...
numWhitePixels = nnz(grayImage); % Sum of non-zero pixels.
numPixels = numel(grayImage);
numBlackPixels = numPixels - numWhitePixels

MATLAB: How to find row and column of a pixel in an Image

Hi, what about this:

[ROWS,COLUMNS] = ndgrid(1:size(I,1),1:size(I,2));
ROWS = ROWS(:);
COLUMNS = COLUMNS(:);

where I is your image.

Best regards, Wolfgang

Best Answer

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MATLAB: How to code the total pixels number and white pixels and black area pixels number

MATLAB: How to find row and column of a pixel in an Image

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