How do I solve imnoise error when inserting variables that store the single English alphabet and its background respectively which are logical image(which are binary image)??

Question

Tuck Wai Yip 2021-7-15

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/879383-how-do-i-solve-imnoise-error-when-inserting-variables-that-store-the-single-english-alphabet-and-its

评论： Simon Chan 2021-7-16

采纳的回答： Simon Chan

在 MATLAB Online 中打开

Error using imnoise Expected input number 1, I, to be one of these types:

uint8, uint16, double, int16, single

Instead its type was logical.

Error in imnoise>ParseInputs (line 107) validateattributes(a, {'uint8','uint16','double','int16','single'}, {}, mfilename, ...

Error in imnoise (line 86) [a, code, classIn, classChanged, p3, p4] = ParseInputs(args{:});

Error in create_images_trial (line 34) Newforegnd_noise = imnoise(Newforegnd, 'gaussian',0, 0.01);

This is the error I received.How should I handle this? Because I need the background and single English alphabet to continue the process as next I will need to threshold on those separately.I attach my code below.

%create blank image
 w = 150;
 h = 150;
 blankImage= 255*ones(w,h,3,'uint8');
 %position of the letter in the empty cell
 position_x = (w+1)/2;
 position_y = (h+1)/2;
 % varying the font size, start from 10 to 16
 font_start = 58;
 font_end = 64; 
num_fontsA = font_start:2:font_end;
 % get the number of fonts
 numImagesA = length(num_fontsA);
 % create a cell array with number of fonts to fill in the image in next step
 A = cell(1, numImagesA);
% for loop to create letter 'A'
 % grayscale
 % store into the cell array
for i=1:numImagesA
 for font_size = num_fontsA(i)
         img= insertText(blankImage,[position_x position_y],'A','Font','Times New Roman','FontSize',font_size,'TextColor','black','BoxColor','w','BoxOpacity',0,'AnchorPoint','Center');
         grayImage= rgb2gray(img);
         BWImage = ~grayImage;
        background = BWImage == 0;
        foreground = ~background;
        Newforegnd = foreground;
%         figure('Name','Background and Object');
         montage({Newforegnd, background});
        % Apply noise on the image
        % Apply noise on the alphabet, using 0.01 standard deviation
        Newforegnd_noise = imnoise(Newforegnd, 'gaussian',0, 0.01);
        %Apply noise on the background, using 0.01 standard deviation
        background_noise = imnoise(background, 'gaussian',0, 0.01);
        %Format figure name into string with font size automatically
        %iterates using assigned variable font_size
        % %d is decimal notation for the font size variable as it is in
        % whole number
        f = figure('Name','Foreground & background image before & after adding noise','NumberTitle','off');
        p = uipanel('Parent',f,'BorderType','none');
        p.Title = sprintf('For alphabet with font size of %d ',font_size);
        p.TitlePosition = 'centertop';
        %divide the figure into subplot
        %which above is foreground of the alphabet
        %while the background of alphabet at below
        subplot(2,2,1,'Parent',p);
        imshow(Newforegnd);
        h1 = gca;
        h1.Visible = 'on';
        title("Foreground image of the single alphabet");
        subplot(2,2,2,'Parent',p);
        imshow(Newforegnd_noise);
        h2 = gca;
        h2.Visible = 'on';
        title("Image of the single alphabet(after adding noise) ");
        subplot(2,2,3,'Parent',p); 
        imshow(background);
        h3 = gca;
        h3.Visible = 'on';
        title("Background of the single alphabet");
        subplot(2,2,4,'Parent',p);
        imshow(background_noise);
        h4 = gca;
        h4.Visible = 'on';
        title("Background of the single alphabet(after adding noise)");

Is that anyone could guide me what to do next for putting the gaussian noise ,the image now is in logical form,it can be grayscale it is made into binary because I separate the alphabet and its background into different variable?Thank you.

4 个评论
显示 2更早的评论隐藏 2更早的评论

Simon Chan 2021-7-16

在 MATLAB Online 中打开

Noticed the size of the figures are not the same, since I only resize the images with noise only

Newforegnd_noise = imnoise(double(Newforegnd), 'gaussian',0, 0.01);
Newforegnd_noise = imresize(Newforegnd_noise,[120 120]);
%
background_noise = imnoise(double(background), 'gaussian',0, 0.01);
background_noise = imresize(background_noise,[120 120]);

Tuck Wai Yip 2021-7-16

编辑：Tuck Wai Yip 2021-7-16

Sorry,it is because I viewed this in phone,I overlook the whole output.thank you for your help,I will try this straightaway after this.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Simon Chan 2021-7-15

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/879383-how-do-i-solve-imnoise-error-when-inserting-variables-that-store-the-single-english-alphabet-and-its#answer_747513

编辑：Simon Chan 2021-7-15

在 MATLAB Online 中打开

Newforegnd & background are BW image which is class logical and imnoise does not support.

You may change it to class double or uint8 as follows as an example.

Newforegnd_noise = imnoise(double(Newforegnd), 'gaussian',0, 0.01);
        %Apply noise on the background, using 0.01 standard deviation
background_noise = imnoise(double(background), 'gaussian',0, 0.01);
%
%
%
Newforegnd_noise = imnoise(uint8(Newforegnd*255), 'gaussian',0, 0.01);
        %Apply noise on the background, using 0.01 standard deviation
background_noise = imnoise(uint8(background*255), 'gaussian',0, 0.01);

2 个评论
显示无隐藏无

Walter Roberson 2021-7-16

Right. imnoise() expects to be adding noise that only a fraction of the range of values for the data type, but logical() only has values 0 and 1 -- you cannot have 0.02 as a logical value for example.

With logical only supporting 0 and 1, requesting 0.01 gaussian would not round to 1 until you reached 50 standard deviations. If I read the tables right, that is a probability of about

Simon Chan 2021-7-16