Is there any possible to save the logical image in png?

I want to save my image logical as .png. But I got uint8 datatype after save it.

Is it possible to save an image in logical format png?

[Dyuman Joshi]

How are you saving the file?

And how are you checking the data type of the file after saving it?

Here, I am (successfully) storing a logical image as a PNG file with imwrite() -

img = logical(randi(2, 500, 500)-1);
class(img)

ans = 'logical'

imshow(img)

imwrite(img, 'Image.png')

z = imread('Image.png');
class(z)

ans = 'logical'

[Dayangku Nur Faizah Pengiran Mohamad]

Hi thanks for your respon Sir.

I still don't get it. How do save the image logical? Here's my codes:

fontSize = 16;
I=imread('rescale8.jpg');
subplot(1, 2, 1);
imshow(I, []);
axis('on', 'image');
%caption = sprintf('Original Image : "%s"', I);
drawnow;
hp = impixelinfo();
hFig1 = gcf;
hFig1.Units = 'Normalized';
hFig1.WindowState = 'maximized';
hFig1.Name = 'Demo by Image Analyst';

% Mask to find the lesion.
hsvImage = rgb2hsv(I);
mask = hsvImage(:,:,2) > 0.3;
% Fill holes.
mask = imfill(mask, 'holes');
% Display the test image full size.
subplot(1, 2, 2);
imshow(mask, []);
axis('on', 'image');
%caption = sprintf('Mask Image : "%s"', I);
%title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
hp = impixelinfo();

subplot(1, 2, 1);
% Here is where we actually get the boundaries for each blob.
boundaries = bwboundaries(mask);
% boundaries is a cell array - one cell for each blob.
% In each cell is an N-by-2 list of coordinates in a (row, column) format.  Note: NOT (x,y).
% Column 1 is rows, or y.    Column 2 is columns, or x.
numberOfBoundaries = size(boundaries, 1); % Count the boundaries so we can use it in our for loop
% Here is where we actually plot the boundaries of each blob in the overlay.
hold on; % Don't let boundaries blow away the displayed image.
for k = 1 : numberOfBoundaries
	thisBoundary = boundaries{k}; % Get boundary for this specific blob.
	x = thisBoundary(:,2); % Column 2 is the columns, which is x.
	y = thisBoundary(:,1); % Column 1 is the rows, which is x.
	plot(x, y, 'g-', 'LineWidth', 1); % Plot boundary in red.
    imwrite(logical(mask),'maskre8.jpg');
end

[Dayangku Nur Faizah Pengiran Mohamad]

I'm confused where to put the codes:

img = logical(randi(2, 500, 500)-1);

in my code. Can you help me out? The img refer to the image, am I right?

[Dayangku Nur Faizah Pengiran Mohamad]

Array indices must be positive integers or logical values.

Error in createMask2 (line 42)
    z=imwrite(logical(mask(randi(2, 512,512)-1)),'maskre8.jpg');

I got this error.

[Dyuman Joshi]

Can you attach the file rescale8.jpg so I can run your code?

The code I wrote was just an example to show that logical images can be saved as PNG.

[Dayangku Nur Faizah Pengiran Mohamad]

Here the image file.

[Walter Roberson]

Change

    z=imwrite(logical(mask(randi(2, 512,512)-1)),'maskre8.jpg');

to

    imwrite(randi([0 1], 512, 512, 'logical'), 'maskre8.png')

Note that JPEG has no possibility of storing images as logical.

Answer 1

[Dyuman Joshi]

The variable mask() is already a logical array. You don't need to convert it to logical().

Just write it as a PNG image -

fontSize = 16;
I=imread('rescale8.jpg');
subplot(1, 2, 1);
imshow(I, []);
axis('on', 'image');
%caption = sprintf('Original Image : "%s"', I);
drawnow;
hp = impixelinfo();
hFig1 = gcf;
hFig1.Units = 'Normalized';
hFig1.WindowState = 'maximized';
hFig1.Name = 'Demo by Image Analyst';
% Mask to find the lesion.
hsvImage = rgb2hsv(I);
mask = hsvImage(:,:,2) > 0.3;
% Fill holes.
mask = imfill(mask, 'holes');
class(mask)

ans = 'logical'

% Display the test image full size.
subplot(1, 2, 2);
imshow(mask, []);
axis('on', 'image')

%% Write mask() as a png image
imwrite(mask, 'maskre8.png')