error_level_difference/perform_kstest.m at master · math496/error_level_difference · GitHub

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function [ ksResults ] = perform_kstest( img, deltaRow, deltaCol )
%UNTITLED Summary of this function goes here
%   Detailed explanation goes here

    %deltaCol = 8;
    %deltaRow = 8;

    index = 1; jindex = 1;

    rowIndex = 1;

    [ rowSize, colSize, colorSize ] = size(img);
    ksResults = zeros( rowSize/deltaRow, colSize/deltaCol, colorSize );

    % Iterating across the rows... we'll fix on one set of rows
    while (rowIndex + deltaRow) <= rowSize

        colIndex = 1;
        jindex = 1;
        % Iterating across one row, we'll iterate over a set of columns
        while colIndex <= colSize

            block1 = getBlock( img, rowIndex, deltaRow, colIndex, deltaCol);
            block2 = getBlock( img, rowIndex+deltaRow, deltaRow, colIndex, deltaCol );

            % We have 2 blocks of rows and cols, iterate over their
            % sub matrices..
            for colorIndex = 1:3

                [ count1, ~ ] = imhist( block1( :, :, colorIndex ) );
                [ count2, ~ ] = imhist( block2( :, :, colorIndex ) );

                cdf1 = cumsum( count1 ) / sum( count1 );
                cdf2 = cumsum( count2 ) / sum( count2 );

                ksResults( index, jindex, colorIndex ) = ...
                    kstest2( cdf1, cdf2, 'Alpha', 0.05 );

            end

            colIndex = colIndex + deltaCol;
            jindex = jindex + 1;

        end

        rowIndex = rowIndex + deltaRow;
        index = index + 1;

    end

end