Question about hair removal matlab code.

Question

wei huang 2016-11-9

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/311333-question-about-hair-removal-matlab-code

评论： SOMNATH BAKSI 2025-1-19

Hello all! I am doing a program about hair removal. And I found a code online but part of this code I couln't understand. The final part(the loop part) was really confused me.

img_b is a binary image and after dilation we could get the img_b binary image, which the black part is skin and the white part is hair. Thus, the 'for' part in the final loop is to decide if this pixel is skin or hair, if the pixel is in the skin part then it keeps the same pixel value as the original image; if the pixel is in the hair part, then do 'else' and calculate it for removing hair.

So here comes the question, I do not understand the calculation part in 'else' and the meaning of parameter r.When I change the value of r into a bigger one, the running speed gets slower. So I wonder could anyone give me a guide about this part please?when I change the value of r into a bigger one, the running speed gets slower. Thank you!

Images are listed below: the first image is which we need to deal with and the second image is the processed image.

Updated on Mar. 7th 2019: Sorry guys forgot to put the otsu function. Already put it in case anyone need it.

if true
clear;
clc;
r=7;
se1_para = 3;
se2_para = 2;
img_old = imread('D:\MATLAB1\bin\picsam\03-2.jpg');
figure(1),imshow(img_old);
[x,y,z] = size(img_old);
img = rgb2gray(img_old);
se1 = strel('disk',se1_para);
img_c = imclose(img,se1)
figure(2), imshow(img_c,[]);
img_fur = double(img_c) - double(img);
figure(3),imshow(img_fur,[]);
[X Y]=meshgrid(1:x);
tt=(X-280).^2+(Y-280).^2<280^2;
thresh = otsu(img_fur(tt),sum(tt(:)));
img_b = (img_fur>thresh);
figure(4),imshow(img_b);
se2 = strel('disk',se2_para);
img_b =imdilate(img_b,se2);
figure(5),imshow(img_b);
img_new = uint8(zeros(x,y,z));
for i = 1:x 
  for j = 1:y        
      if img_b(i,j) == false  
          img_new(i,j,:) = img_old(i,j,:);
      else           
          ttt = img_old(max(1,i-r):min(i+r,x),max(j-r,1):min(j+r,y),:);
          no_efficient_pix = cat(3,img_b(max(1,i-r):min(i+r,x),max(j-r,1):min(j+r,y)),not(tt(max(1,i-r):min(i+r,x),max(j-r,1):min(j+r,y))));
          no_efficient_pix = any(no_efficient_pix,3);
          ttt = ttt.*repmat(uint8(not(no_efficient_pix)),[1,1,3]);
          efficient_pix_num = (2*r+1)^2-sum(no_efficient_pix(:));
          img_new(i,j,:) = uint8(sum(sum(ttt))./efficient_pix_num);           
      end       
  end   
end
figure(6),imshow(img_new,[]);
end
function thresh = otsu(data,pix_num)
img_var = zeros(256,1);
for i=1:256
     w0 = sum(sum(data<=i-1))./pix_num;
     w1 = 1-w0;
     u0 = sum(sum(data.*double(data<=i-1)))./(w0*pix_num);
     u1 = sum(sum(data.*double(data>i-1)))./(w1*pix_num);
     img_var(i) = w0.*w1.*((u0-u1).^2);
end
[~,I] = max(img_var);
thresh = I-1;
end

6 个评论
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Image Analyst 2019-11-20

J, attach your image and code so we can run it and fix it.

SARAH LONER 2019-11-20

this are my images sir nd i have used the above code for removing hair from skin. please help me on on this

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Answer 1

Luis Enciso 2021-7-13

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/311333-question-about-hair-removal-matlab-code#answer_746083

在 MATLAB Online 中打开

I fixed the given code in this way, it works fine in squared cropped images:

close all
clear;
clc;
r=7;
se1_para = 3;
se2_para = 2;
img_old = imread('image.jpg');
figure(1),imshow(img_old);
% crop
[x,y,z] = size(img_old);
d = y-x;
im_crop = img_old(:,round(d/2)+1:y-(d-round(d/2)),:);
[x,y,z] = size(im_crop);
img = rgb2gray(im_crop);
se1 = strel('disk',se1_para);
img_c = imclose(img,se1)
figure(2), imshow(img_c,[]);
img_fur = double(img_c) - double(img);
figure(3),imshow(img_fur,[]);
[X Y]=meshgrid(1:x);
tt=(X-x/2).^2+(Y-y/2).^2<(x+y)^2;
thresh = otsu(img_fur(tt),sum(tt(:)));
img_b = (img_fur>thresh);
figure(4),imshow(img_b);
se2 = strel('disk',se2_para);
img_b =imdilate(img_b,se2);
figure(5),imshow(img_b);
img_new = uint8(zeros(x,y,z));
for i = 1:x 
  for j = 1:y        
      if img_b(i,j) == false  
          img_new(i,j,:) = im_crop(i,j,:);
      else           
          ttt = im_crop(max(1,i-r):min(i+r,x),max(j-r,1):min(j+r,y),:); % region 
          no_efficient_pix = cat(3,img_b(max(1,i-r):min(i+r,x),max(j-r,1):min(j+r,y)),not(tt(max(1,i-r):min(i+r,x),max(j-r,1):min(j+r,y))));
          no_efficient_pix = any(no_efficient_pix,3);
          ttt = ttt.*repmat(uint8(not(no_efficient_pix)),[1,1,3]);
          efficient_pix_num = (2*r+1)^2-sum(no_efficient_pix(:));
          img_new(i,j,:) = uint8(sum(sum(ttt))./efficient_pix_num);           
      end       
  end   
end
figure(6),imshow(img_new,[]);
function thresh = otsu(data,pix_num)
img_var = zeros(256,1);
for i=1:256
     w0 = sum(sum(data<=i-1))./pix_num;
     w1 = 1-w0;
     u0 = sum(sum(data.*double(data<=i-1)))./(w0*pix_num);
     u1 = sum(sum(data.*double(data>i-1)))./(w1*pix_num);
     img_var(i) = w0.*w1.*((u0-u1).^2);
end
[~,I] = max(img_var);
thresh = I-1;
end