How can I automatically crop only the region of face and neck from the front view and side view images of a person?

I have been able to convert the whole image into a binary image and do my processing further on the image but i specifically want to do something with the neck of a person. I have 30 people in my data set, I have to have a universal code that works for all 30 people's image in one go, I have been able to do everything just I want an automatic method in which I feed in the binary images of side view and front view of the person and it either returns me the cropped face+neck part or stores the cropped portion in some directory. Here's the code where I am manually cropping the image and going further with processing.

if true
  file2 = 'Dilfr.jpg';
  file2r = imread(file2);
  f2 = rgb2gray(file2r);
  f3 = imbinarize(f2,'adaptive');
  imcrop(f3); %%%I need an automatic replacement here
  f4 = 'dcrop2.jpg';
  F1 = imread(f4);
  F2 = im2bw(F1);
  filled = imfill(F2,'holes');
  holes = filled & ~F2;
  bigholes = bwareaopen(holes, 800);  
  F3 = bigholes;

    figure,
    imshow(F3);
  end

[Image Analyst]

Please also attach 'dcrop2.jpg'.

I'd start by start scanning down from the top of the silhouette (binary image) and pick a narrow part that seems like it's probably the neck.

[Shreyansh Dubey]

dcrop2 is just the rectangular manually cropped image from a little portion above the head to little below the neck, that's it all. I want to do the same rectangular cropping automatically for all images only that small portion is needed for my processing. I hope the problem is clearly understood now.

[Shreyansh Dubey]

Please just help me to crop a rectangular or a square portion that consists of both face and neck from the image given above, automatically for every image that I feed in file2 variable. That's all I want. Note: All the images in my data set have been taken in the same posture, at the same place and from the same distance.

Answer 1

[Image Analyst]

Try this:

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 = 20;

%===============================================================================
% Read in gray scale demo image.
folder = pwd; % Determine where demo folder is (works with all versions).
baseFileName = 'dilfr.JPG';
% Get the full filename, with path prepended.
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
rgbImage = 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(rgbImage)
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(rgbImage);
  % 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 = rgbImage(:, :, 2); % Take green channel.
else
  grayImage = rgbImage; % It's already gray scale.
end
% Now it's gray scale with range of 0 to 255.

% Display the image.
subplot(2, 3, 1);
imshow(grayImage, []);
title('Original Image', 'FontSize', fontSize, 'Interpreter', 'None');
axis('on', 'image');
hp = impixelinfo();

%------------------------------------------------------------------------------
% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);
% 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;

% Show the histogram
subplot(2, 3, 2);
[counts, grayLevels] = histcounts(grayImage(:));
counts(counts == max(counts)) = 0; % Suppress spike
bar(grayLevels(1:end-1), counts);
grid on;
title('Histogram of Original Image', 'FontSize', fontSize, 'Interpreter', 'None');

% Median Filter to get rid of seams in wall.
windowSize = 11;
mfImage = medfilt2(grayImage, [windowSize, windowSize]);
% Display the image.
subplot(2, 3, 3);
imshow(mfImage, []);
title('Median Filtered Image', 'FontSize', fontSize, 'Interpreter', 'None');
axis('on', 'image');
hp = impixelinfo();

windowSize = 13;
sdImage = stdfilt(mfImage, ones(windowSize));
% Display the image.
subplot(2, 3, 4);
imshow(sdImage, []);
title('Standard Deviation Image', 'FontSize', fontSize, 'Interpreter', 'None');
axis('on', 'image');
hp = impixelinfo();

% Show the histogram
subplot(2, 3, 5);
[counts, grayLevels] = histcounts(sdImage(:));
counts(counts == max(counts)) = 0; % Suppress spike
bar(grayLevels(1:end-1), counts);
grid on;
title('Histogram of Standard Deviation Image', 'FontSize', fontSize, 'Interpreter', 'None');

% Binarize the image
binaryImage = sdImage >= 25;
% Remove blobs touching border.
binaryImage = imclearborder(binaryImage);

% Take largest blob
binaryImage = bwareafilt(binaryImage, 1);

% Display the image.
subplot(2, 3, 6);
imshow(binaryImage, []);
title('Binary Image', 'FontSize', fontSize, 'Interpreter', 'None');
axis('on', 'image');
hp = impixelinfo();

% Get widths as a function of row
widths = zeros(rows, 1);
for row = 1 : rows
  col1 = find(binaryImage(row, :), 1, 'first');
  col2 = find(binaryImage(row, :), 1, 'last');
  if ~isempty(col1)
    widths(row) = col2 - col1 + 1;
  end
end
figure
subplot(2, 1, 1);
plot(widths, 'b-', 'LineWidth', 2);
xlabel('Row', 'FontSize', fontSize);
ylabel('Width', 'FontSize', fontSize);

% Find valleys byinverting and finding peaks
[peakValues, indexes] = findpeaks(-widths);
peakValues = -peakValues; % Negate to flip over.
grid on;
hold on;
plot(indexes, peakValues, 'r+', 'MarkerSize', 12, 'LineWidth', 2);

% The neck is the first peak.
neckRow = indexes(1);

% Display the original image again.
subplot(2, 1, 2);
imshow(grayImage, []);
axis('on', 'image');
title('Original Image', 'FontSize', fontSize, 'Interpreter', 'None');
axis('on', 'image');
hp = impixelinfo();

% Put a line up over the neck.
hold on;
line(xlim, [neckRow, neckRow], 'Color', 'r', 'LineWidth', 2);
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);

[Shreyansh Dubey]

I thank you and highly appreciate your work Mr Image Analyst sir, this was although a learning for me but this has not been able to solve my problem, all i wanted was just this kind of image to be obtained automatically,

If you could just tell tell me how can i achieve this that would be really of great help sir, thanks in advance.

[Image Analyst]

As you scan down the lines in the loop, fill in the binary image from left to right:

binaryImage(row, col1:col2) = true;

Then, after you have determined the neck row, erase the binary image just from the neck down.

binaryImage(neckRow+1:end, :) = false;

Then call regionprops() and ask for centroid.

props = regionprops(binaryImage, 'Centroid');

Then make up a rectangle array using the centroid and a predetermined size that you want for the head such that it's the right size and centered on the centroid.

width = 75; % Whatever.
height = 80; % Whatever.
xLeft = props.Centroid(1) - width/2;
yTop = props.Centroid(2) - height/2;
croppingRectangle = [xLeft, yTop, width, height];

Then call imcrop() on the original gray scale image.

croppedImage = imcrop(grayImage, cropppingRectangle);

Pretty easy but let us know if you run into problems.

[Shreyansh Dubey]

i shall try this, thanx