How to detect faces without using vision.Cas​cadeObject​Detector

I am new in matlab I am trying to detect faces without using built in functions but I not able to do this any help.

Answer 1

[yanqi liu]

yes，sir，may be use ycbcr color segment to identify face as simple method

if possible，can you upload your image to analysis？

[Mahmoud Abdelaziz]

Here it is

[yanqi liu]

yes，sir，use simple ycbcr process，such as

I = imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/943314/image.png'); 
J = rgb2ycbcr(I);
y = J(:,:,1);
[rows, cols] = size(y);
m = [120 130]';
sig = [70  40
         40 200];   
cbcr = zeros(2,1); 
mask=zeros(rows,cols);    
for i = 1:rows
    for j =1:cols
        cbcr(1) = J(i,j,3); 
        cbcr(2) = J(i,j,2);
        P(i,j) = exp(-0.5*((cbcr-m)')*(inv(sig))*(cbcr-m));   
    end
end
mask = P < 1e-2;
bw = imopen(mask, strel('disk', 15));
bw = imclose(bw, strel('disk', 3));
bw = imfill(bw, 'holes');
bw = bwareaopen(imopen(bw, strel('disk', 25)), 2e4);
stats = regionprops(bw);
figure; imshow(I, []);
for i = 1 : length(stats)
    hold on; rectangle('position', stats(i).BoundingBox, 'EdgeColor', 'g', 'LineWidth', 2)
end

[Mahmoud Abdelaziz]

Thank you for helping but this only work for this image, if I change the image it does not work properly.

[yanqi liu]

yes，sir，if use different image，may be check

https://ww2.mathworks.cn/matlabcentral/fileexchange/73947-mtcnn-face-detection?s_tid=srchtitle

such as

im = imresize(I, 0.3, 'bilinear');
detector = mtcnn.Detector("MinSize", 15, "MaxSize", 308, "PyramidScale", 5);
[bboxes, scores, landmarks] = detector.detect(im);
displayIm = insertObjectAnnotation(im, "rectangle", bboxes, scores, "LineWidth", 2);
imshow(displayIm)
hold on
for iFace = 1:numel(scores)
    scatter(landmarks(iFace, :, 1), landmarks(iFace, :, 2), 'filled');
end