How can detect or remove object that have area between 2 values?

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Erfaneh 2014-8-15

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https://ww2.mathworks.cn/matlabcentral/answers/150960-how-can-detect-or-remove-object-that-have-area-between-2-values

评论： Amir 2014-8-16

I extract some object with threshold in some images. I earn their area with regionprops function. I want to detect the objects that their area is between two values(Max & Min values), or to remove all objects that their area is less than and greater than 2 values. Can some one help me?

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Amir 2014-8-15

Can you please attach one example image.

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Answer 1

Amir 2014-8-15

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/150960-how-can-detect-or-remove-object-that-have-area-between-2-values#answer_148721

编辑：Amir 2014-8-15

在 MATLAB Online 中打开

Please try this code, I tried to write this code very clear (not efficient), please let me know if it is not clear

   clc
    clear all
    close all
    [filename, pathname] = uigetfile('*','File Selector');
    I = imread(strcat(pathname,'\',filename)); % for example FileName='MyImage.jpg'
    I=im2bw(I);
    BW = edge(I,'canny',0.1);
    [bw, loc2]= imfill(BW,'holes');
    % http://www.mathworks.co.uk/help/images/ref/regionprops.html
    rp = regionprops(bw,'All'); % you can specify the parameters which you need
    ObjArea=zeros(size(rp,1),1);
    CenterX=zeros(size(rp,1),1);
    CenterY=zeros(size(rp,1),1);
    for i=1:size(rp,1)
        ObjArea(i)=rp(i).Area;
        CenterX (i)= rp(i).Centroid(1);
        CenterY (i)= rp(i).Centroid(2);
        % you can add other properties (for example area, perimeter etc here)
    end
  Final=[ObjArea CenterX CenterY];
  imshow(I);
  hold on
  for i=1:size(Final,1)
      text(Final(i,2),Final(i,3),num2str(Final(i,1)),...
      'HorizontalAlignment' , 'center',...
      'VerticalAlignment' , 'middle');
  end
  title('Area of Particles');
prompt = {'Minimum size:','Maximum size:'};
dlg_title = 'Minimum and maximum sizes';
num_lines = 1;
def = {'5000','15000'};
answer = inputdlg(prompt,dlg_title,num_lines,def);
MinMaxSize =str2num(char(answer));
MinSize=MinMaxSize(1,1); MaxSize= MinMaxSize(2,1);
Removed=[];
  for i=1:size(rp,1)
      if rp(i).Area<MinSize || rp(i).Area>MaxSize
        Removed=[Removed i];
      end
  end
rp(Removed)=[];
NewImage= zeros(size(I));
  for i=1:size(rp,1)
        OneOject= rp(i).PixelList;
        for j=1:length(rp(i).PixelList)
            OneRow = OneOject(j,:);
            NewImage (OneRow(2),OneRow(1))=1;
        end
  end
figure
imshow(NewImage)
title('Area of Particles - between Minimum and Maximum');

Step 1: Open your image

Step 2: See size of objects and choose the range

Step 3: Objects with the size between minimum and maximum will be shown

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Image Analyst 2014-8-15

For an alternate size filtering method which was recommended to me by the Mathworks when I was first learning MATLAB, and which I still use, see my Image Processing Tutorial http://www.mathworks.com/matlabcentral/fileexchange/25157-image-segmentation-tutorial---blobsdemo-- It uses ismember() and find() instead of for loops. The method is adaptable to any filtering of any property values (perimeter, MajorAxisLength, etc.).

Amir 2014-8-16