I want to display image with axes labelled with XData and YData as it possible with imshow.
My simulation generates new image each step.
I found no way to do this neither with Video Viewer nor with Matrix Viewer.
May it is possible to hook them somehow?
Related
I tried using axes for displaying images in Gui.But, before displaying any images, the axes is shown with a plot figure while running the GUI, something like below.
You can see the default axes being displayed. Is there a way to display the axes in running GUI without displaying these plot figures? So that when the image is not displayed in the axes, nothing is displayed. Thanks in advance.
UPDATE 1
I have used 9 axes here, thus the long trail of y axis.
Yes, you can use
axis off
To remove the axes from the empty plots. Then use
axis on
When you actually plot something to bring them back.
Best,
I'm creating a simple GUI in MATLAB and I'm trying to create a figure that contains a 2d plot on an axes, all is working well, but I have a rough time trying to figure out how to fix the position of the axes/plot.
The axes seems to scale with the figure window size. If I maximize the figure on my screen, the axes is maximized within, etc. What I want to accomplish is to have a row of buttons beneath the plot on the same figure as the plot, basically an area of 50 (ish) pixels tall that the plot does not encroach on. I know how to do this in HTML, but I can't figure out a good way in MATLAB.
Any alternative approaches would also be greatly appreciated.
Change the units of the axes to anything other than 'normalized', like 'pixels'. Then it won't automatically resize with the figure. From this documentation page:
When you create a graph, MATLAB® creates an axes to display the graph. The axes is sized to fit in the figure and automatically resizes as you resize the figure. MATLAB applies the automatic resize behavior only when the axes Units property is set to normalized (the default).
Use set(gca,'Position',pos) where pos = [x y w h] to set the position and size of the axes in the units you chose.
See this answer for an example and a function for holding an axis size once you have it in place.
I'm analyzing some sound clips using the spectrogram() function in MATLAB. I would like to save the spectrogram as an image (jpg, png, etc). But regardless of what image format I save the figure in, the resulting image always looks different ("spotty") from what I see in the figure.
Here's an example of the spectrograms: Matlab Figure vs. Saved Image
All I want is to save exactly what I see in the figure as an image. I've already tried saving the figure in all the image formats possible but all of them are producing the same "spotting" effect. I've also tried both manual saving (click on file -> save as) and programmatically using the print() and the saveas() functions. Same result every time.
Any help would be appreciated!
What is the data range of your spectrogram?
One of reasons might be that your spectrogram range is out of the [0,1] region for double images or [0,255] for uint* images (your white spots on saved image are suspiciously close to the local minima on MatLab figure).
Another guess might be that you are using imwrite function, in particular its imwrite(X,map,filename,fmt) syntax. MatLab documentation explains:
imwrite(X,map,filename,fmt) writes the indexed image in X and its associated colormap map to filename in the format specified by fmt. If X is of class uint8 or uint16, imwrite writes the actual values in the array to the file. If X is of class double, imwrite offsets the values in the array before writing, using uint8(X–1). map must be a valid MATLAB colormap. Note that most image file formats do not support colormaps with more than 256 entries.
so the uint8(X–1) might be the source of the white spots.
Though have no idea why they appear after print()'ing.
I found a work-around for this problem by using the pcolor() function, which is essentially a rotated surf() function plotted in a grid format (doc). After tinkering with the spectrogram() function more, I'm convinced that these "spotting" artifacts have nothing to do with the data format, property, or scale. The problem seems to lie in the way MATLAB plots and visualizes 3D plots. I tried plotting with the mesh() function as well and it produced a different kind of "spotting" effect. pcolor() works because it's a 2D visualization of a 3D plot.
This is how spectrogram() plots the image using surf() (adapted from the doc):
[S,T,F,P] = spectrogram(X,256,250,256,2000);
surf(T,F,abs(S),'EdgeColor','none');
axis tight; view(0,90);
... and this is how to use pcolor() to plot a save-friendly image:
[S,T,F,P] = spectrogram(X,256,250,256,2000);
h = pcolor(T,F,abs(S));
set(h,'EdgeColor','none');
The white spots are an OpenGL issue, which is the renderer used in spectrogram()'s internal call to surf().
Since you are interested in plotting a 2D visualization, change the renderer for the current figure to zbuffer:
set(gcf, 'renderer', 'zbuffer');
where gcf means "get current figure". The white spots are now gone.
Note that you can also select the zbuffer renderer when you create the figure, before calling spectrogram():
myNewFig = figure('renderer','zbuffer');
I'm using MATLAB R2012a to develop a GUI for manual medical image segmentation. In particular, I want this regions to train a classifier for automatic brain tissue classification.
The GUI I design contains 2 axes, with tags 'figureImage' and 'figureVOI', respectively. In the first one I want to display a single slice of a 3D MRI scan, and in the other one I want to show the mask associated to that slice. I allow the user to move between slices using a scroll bar.
I'm using a 3D matrix to represent the image ('image'), and a 3D matrix to represent the mask ('voi'), both of them in the handles structure. I initialize the 'voi' matrix with zeros when the GUI is loaded.
The code I applied when the user clics on the scroll bar is the next:
% update the number of the actual slice
handles.actualSlice = round(get(handles.sliceSelector, 'Value'));
% update the image and the mask
axes(handles.figureImage)
imshow(handles.image(:, :, handles.actualSlice));
axes(handles.figureVOI)
imshow(handles.voi(:, :, handles.actualSlice));
However, when I clic on the scroll bar, the GUI just scroll to cut nº 70 aprox., and then all then the GUI stops to update the axes. If I close the window and try to run the GUI again, and MATLAB shows me a system error.
I want to know what I'm doing bad, and if there is another way to do what I need to do. Thanks a lot! :)
This is fairly easy question. You may have have different axis names and axes positioned at different locations.Then you route your images to the respective axes depending on which ever you want to choose to work with as the axes and you can choose both at the same time. Hope this helps. Good luck.
I want to write a software that reads the satellite data from a text file and plots graph for different parameters of the oceans. The idea came from Oceonographic Data View(ODV).
My problem is plotting a graph on an image of the Indian ocean, where the image must be overlapped with the graph. Also, on zooming the area, the image with the graph could be zoomed.
How can I do this?
To load and display images, the Displaying Bit-Mapped Images tutorial from MathWorks may not be a bad place to start.
To overlay plots on the image, using hold on followed by plot should work.
An important part will be to have a sensible metric when displaying your image that allows you to place your overlays accurately. In the example below, notice the first and second arguments to image that define this; you could replace it by say linspace(0,1,size(X,1)) if you wanted it scaled between 0 and 1 instead of between 1 and 480 as below.
load mandrill
image(1:480,1:500,X) % display image
colormap(map)
hold on % prevent subsequent plot commands from destroying the image
plot([1 480],[100 100],'w','LineWidth',2) % plot an overlay line