I use the following lines of code to plot the images:
for t=1:subplotCol
subplot(subplotRow,subplotCol,t)
imagesc([1 100],[1 100],c(:,:,nStep*t));
colorbar
xlabel('X-axis')
ylabel('Y-axis')
title(['Concentration profile at t_{',num2str(nStep*t),'}'])
subplot(subplotRow,subplotCol,subplotCol+t)
hold on;
plot(distance,gamma(:,1,t),'-ob');
plot(distance,gamma(:,2,t),'-or');
plot(distance,gamma(:,3,t),'-og');
xlabel('h');ylabel('\gamma (h)');
legend(['\Theta = ',num2str(theta(1))],...
['\Theta = ',num2str(theta(2))],['\Theta = ',num2str(theta(3))]);
end
I get the following subplot with images:
As you can see the images in first row are now scaled equally on X and Y axis (Y axis is longer than the X-axis) even though the size of the image matrix is 100x100 for each image on first row.
Can someone help with how to make images in first row look like squares than rectangles which I get currently. Thanks.
Use the dataAspectRatio properties of the axes, and set it to [1 1 1]
%# create a test image
imagesc(1:10,1:10,rand(10))
%# you should use the handle returned by subplot
%# instead of gca
set(gca,'dataAspectRatio',[1 1 1])
Another method is to use the command axis equal
Regarding the size of different objects, you can set the exact position of each axes on the figure, for example for the first one use:
subplot(2,2,1); set(gca,'Position',[0.05 0.05 0.4 0.4])
Related
I used matlab code.
img = imread('cmap3.png')
map = jet(256)
ind = rgb2ind(img,map)
colormap(map)
cm = colormap('gray)
image(ind)
Through above code, I got the .
I want to save just the gray scale image without any graduations and numbers on x,y axis.
How do I remove them and save gray scale image?
If you use imwrite, you won't save the axes' labels.
For actual plots, there exists a different solutions, eg. described here: set the axis to start at the very left bottom corner so that there is no space left for descriptions: set(gca, 'Position',[0 0 1 1]). Than you can even use print to save the image/figure.
How should i remove the empty space between these images?i need to combine all these images without any space.
bot=imread('bot.jpeg');
for i= 1:25
subplot(5,5,i),imshow(bot);
end
You need to specify axes' 'Position' property when you create them with subplot.
Also, you have to adjust figure aspect ratio to match that of the image, so that all figures fit without vertical or horizontal space.
If you show a different image in each subplot, all images should have the same aspect ratio, otherwise it's not possible for them to fit in the figure without empty spaces.
bot = imread('peppers.png');
for i= 1:25
subplot('Position',[(mod(i-1,5))/5 1-(ceil(i/5))/5 1/5 1/5])
imshow(bot); %// or show a different image on each subplot
end
p = get(gcf,'Position');
k = [size(bot,2) size(bot,1)]/(size(bot,2)+size(bot,1));
set(gcf,'Position',[p(1) p(2) (p(3)+p(4)).*k]) %// adjust figure x and y size
The most canonical way would be to take a look at this answer by bla here. This answer uses a function from the MATLAB File Exchange in order to achieve the answer. However, that requires learning a new function and playing around with the parameters.
If you want something working immediately, instead of showing each subimage in a separate grid on a plot, I would simply create a new image that stacks all of those images together:
bot_new = repmat(bot, [5 5]);
imshow(bot_new);
repmat takes a matrix and duplicates / stacks / tiles itself together for as many rows and as many columns (or in any dimension) that you want. In this case, I chose to stack the image so that there are 5 rows and 5 columns of it. We next show the stacked image together with imshow.
If we used an example image from MATLAB:
bot = imread('onion.png');
If we ran the above code that tiles the images together and showed the image, this is what we get:
I copy the answer from mathworks:
For each subplot, store its handle.
h = subplot(2,3,1);
Then set the 'position' property of h to be anything you want.
p = get(h, 'pos');
This is a 4-element vector [left, bottom, width, height] which
by default is in normalized coordinates (percentage of
figure window). For instance, to add 0.05 units (5% of
figure window) to the width, do this:
p(3) = p(3) + 0.05;
set(h, 'pos', p);
The SUBPLOT command picks standard values for these
parameters, but they could be anything you want. You
could put axes anywhere on the figure you want,
any size you want.
You can check for it:
http://www.mathworks.com/matlabcentral/newsreader/view_thread/144116
I've got two images, one 100x100 that I want to plot in grayscale and one 20x20 that I want to plot using another colormap. The latter should be superimposed on the former.
This is my current attempt:
A = randn(100);
B = ones(20);
imagesc(A);
colormap(gray);
hold on;
imagesc(B);
colormap(jet);
There are a couple of problems with this:
I can't change the offset of the smaller image. (They always share the upper-left pixel.)
They have the same colormap. (The second colormap changes the color of all pixels.)
The pixel values are normalised over the composite image, so that the first image changes if the second image introduces new extreme values. The scalings for the two images should be separate.
How can I fix this?
I want an effect similar to this, except that my coloured overlay is rectangular and not wibbly:
Just change it so that you pass in a full and proper color matrix for A (i.e. 100x100x3 matrix), rather than letting it decide:
A = rand(100); % Using rand not randn because image doesn't like numbers > 1
A = repmat(A, [1, 1, 3]);
B = rand(20); % Changed to rand to illustrate effect of colormap
imagesc(A);
hold on;
Bimg = imagesc(B);
colormap jet;
To set the position of B's image within its parent axes, you can use its XData and YData properties, which are both set to [1 20] when this code has completed. The first number specifies the coordinate of the leftmost/uppermost point in the image, and the second number the coordinate of the rightmost/lowest point in the image. It will stretch the image if it doesn't match the original size.
Example:
xpos = get(Bimg, 'XData');
xpos = xpos + 20; % shift right a bit
set(Bimg, 'XData', xpos);
So I have this matrix in MATLAB, 200 deep x 600 wide. It represents an image that is 2cm deep x 6cm wide. How can I plot this image so that it is locked into proper dimensions, i.e. 2cm x 6cm? If I use the image or imagesc commands it stretches it all out of shape and shows it the wrong size. Is there a way to lock it into showing an image where the x and y axes are proportional?
Second question, I need to then set this image into a 640x480 frame (20 pixel black margin on left and right, 280 pixel black margin on bottom). Is there a way to do this?
To keep aspect ratio, you can use axis equal or axis image commands.
Quoting the documentation:
axis equal sets the aspect ratio so that the data units are the same in every direction. The aspect ratio of the x-, y-, and z-axis is adjusted automatically according to the range of data units in the x, y, and z directions.
axis image is the same as axis equal except that the plot box fits tightly around the data`
For second question:
third_dimension_size=1; %# for b&w images, use 3 for rgb
framed_image=squeeze(zeros(640,480,third_dimension_size));
framed_image(20:20+600-1,140:140+200-1)= my_600_200_image;
imagesc(framed_image'); axis image;
set(gca,'DataAspectRatio',[1 1 1])
Second question:
new_image = zeros(480,640);
new_image(20:(200+20-1),20:(600+20-1)) = old_image;
As an alternative to the other answers, you might want:
set(gca, 'Units', 'centimeters', 'Position', [1 1 6 2])
Make sure you do this after plotting the image to get the other axis properties correct.
For the second question, take care with the number of colour channels:
new_image = zeros(480,640, size(old_image));
new_image(20:(200+20-1),20:(600+20-1),:) = old_image;
Whilst using Matlab's GUIDE, I wish to plot a line onto an image. I managed to achieve this when I was using only one axis inside the GUI. However upon adding another axis the plot no longer overlays the image.
Initially the plot began to plot on the wrong axis and I realized I had forgotten to set the appropriate axis. However once I had selected the image axis for plotting on, the line which is to be plotted, doesn't lie on top of the image anymore, instead it just replaces the image with a graph of the line only.
My code:
imshow(img(k),'Parent',handles.display)
hold on
x1 = line(k).point1(1);
y1 = line(k).point1(2);
x2 = line(k).point2(1);
y2 = line(k).point2(2);
plot(handles.display,[x1 x2],[y1 y2],'Color','r','LineWidth', 2)
hold off
The code before I added the new axis was identical to above but with the handles.display parameter for the plot().
Any help would be greatly appreciated, thank you in advance.
When you call the HOLD function, you also need to specify the axis handle. Example:
%# create some axes
hAx1 = subplot(121);
hAx2 = subplot(122);
%# draw in first: image with line overlayed
I = imread('coins.png');
imshow(I, 'Parent',hAx1)
hold(hAx1,'on')
plot(hAx1, [1 100], [1 100], 'Color','r', 'LineWidth',2)
hold(hAx1,'off')
%# draw in second
surf(hAx2, peaks)