i have a dataset of 1000 images.now i want to convert the images into grey images.i also want to find the histogram of all the images at a time and want to store the result too

pl help me with codes

Answer 1

[KSSV]

images = dir('*jpg') ;  % give extension of your images 
N = length(images) ;  % total number of images
for i = 1:N 
    I = imread(images(i).name) ;
    [m,n,p] = size(I) ;
    if p==3
       I = rgb2gray(I); 
    end
   [counts,binLocations] = imhist(I) ;
end

Answer 2

[Ameer Hamza]

One of easiest solution is to use Image batch processor app. Type

imageBatchProcessor

in the command window. In the app press the load images button, specify the folder. In the function name specify the name of the function you want to apply to all of the images (for example see the function below) and click process selected. You can also use Parallel processing if you have Parallel Processing Toolbox. It will automatically process all the images. In the end, you can export all the data to the workspace or save to another folder.

function out = batchImage(im)
  out.gray = rgb2gray(im);
  out.hist = histcounts(gray, 0:255);
end

This approach reduces the chances of making an error. And if you are still interested in the code, press the downward arrow on export button and select Generate Function.

Answer 3

[Yuvaraj Venkataswamy]

    imagefiles = dir('*.jpg');
    nfiles = length(imagefiles);
    for ii=1:nfiles
        currentfilename = imagefiles(ii).name;
        I{ii}=imread(currentfilename);
        %  grayscale conversion
       I1{ii}=rgb2gray(I{ii});  % grayscale conversion
       I2{ii}=imhist(I1{ii});
       %  Save results
      str = sprintf('%d', ii);
       filename = fullfile('D:\', sprintf('frame_%03d.JPG', ii));  
       imwrite(I2{ii}, filename); 
    end