I have used matlab's preview window in the following syntax:
figure('Name', 'My Custom Preview Window');uicontrol('String', 'Close', 'Callback', 'close(gcf)');
I am able to successfully get the video stream. Now I want to have a small circle as a region of interest to return the average pixel value within this circle. I want this to be stored and named after a click of a button and recalled later for the further processing.
Could anyone guide me where I can start with?
Please note I dont want user to define ROI instead its always fixed as a small circle at the centre of field view. Whatever the colours comes within the circle I want mean values to be calculated and stored as a reference.
Ps: I am not sure I am correct in calling ROI its simple circle in the field view
You might want to try using a Matlab gui instead of a simple figure. Then you could try something like this.
Related
I am currently working on a program involving shop routing, involving an image map obtained from google maps in the background.
When I try to use the data cursor (to show some irrelevant information), I need to click exactly the right pixel to get the data assigned to the plotted points, else I get a data tip error. Is there any way to disable data cursor mode for the background image while enabling it for the scattered points?
My figure looks like this:
edit: In case this helps, the background is defined as an image with following properties:
CData: [1280×1280×3 double]
CDataMapping: 'direct'
You should be able to set the HitTest property of your background image to off - that way the datatip will only show when you click on your data of interest.
In one GUI (viewer) I have an image that shows a 2D slice through a 3D image cube. A toolbar button opens a second GUI (z-profile) that plots a 2D graph showing the z-profile of one pixel in the image cube. What I want is to be able to update this plot dynamically when a different pixel is clicked in the original viewer GUI. I've looked in to linkdata but I'm not sure if that can be used to link across two GUIs. Is there a simple way to do this without re-creating the second GUI each time a new pixel is clicked and feeding in the new input location?
You can definitely doing it without recreating the second GUI every time.
Without knowing your specific code I would say that you should store a reference to the second GUI in the first GUI, then in a callback for clicking a pixel in the first GUI, change data in the second GUI via the stored reference (e.g. figure handle). You can store arbitrary data in a figure, for example by using function guidata. A bit of code.
...
figure2 = figure();
figure1 = figure('WindowButtonDownFcn',#myCallback);
guidata(figure1, figure2);
...
function myCallback(obj,eventdata)
figure2 = guidata(obj);
...
Even easier but a bit more error-prone would be to use global variables for storing the references.
I plotted few points using scatter and then label them using text. The position of these labels are same as the position of the points + some offset. Some of these text label overlap with each other and hence I moved them interactively (using mouse). I can check the new position of each of these text individually using property editor. However this is very time-consuming. Is there a better way to get the coordinates of all these text-label?
You can use findobj to get handles to text objects that are children of the current axes (or another handle... your choice):
text_handles = findobj('parent',gca,'type','text');
Then you can get the positions of these text objects:
positions = get(text_handles,'position');
You may need to do a bit more work to associate each text object with its data point - I suggest taking advantage of the property system, perhaps via the UserData field, for this, though there are many options.
If you want to do it easily later do this in your plots, for example:
h=text(2.9,7.5,'MyText');
This will put "MyText" at position 2.9, and 7.5.
Then to change the position use:
set(h,'Position',[2.5 7]);
This will change the position to 2.5 and 7.
Later if you need to see tthe position of text again use:
get(h);
Hope this helps.
As when you use subplot to display plots side by side in the same window, I would like a similar function that can do the same for multiple figures. This works:
subplot(2,2,1)
and I am looking for something like this:
subfigure(2,2,1)
Does a build-in function with this advantage exist?
You could write one such function yourself. The idea is to get the screen size:
get(0,'ScreenSize')
then divide it up into sub-regions according to the input parameters. You would also need to account for margins in-between.
Another idea:
create an invisible figure (preferably same aspect ratio as the screen)
call subplot inside it
capture the position of the created axis
delete figure
scale the position captured to fit the screen size, and use it to create the actual figures.
I have a question about the values returned by getPosition. Below is my code. It lets the user set 10 points on a given image:
figure ,imshow(im);
colorArray=['y','m','c','r','g','b','w','k','y','m','c'];
pointArray = cell(1,10);
% Construct boundary constraint function
fcn = makeConstrainToRectFcn('impoint',get(gca,'XLim'),get(gca,'YLim'));
for i = 1:10
p = impoint(gca);
% Enforce boundary constraint function using setPositionConstraintFcn
setPositionConstraintFcn(p,fcn);
setColor(p,colorArray(1,i));
pointArray{i}=p;
getPosition(p)
end
When I start to set points on the image I get results like [675.000 538.000], which means that the x part of the coordinate is 675 and the y part is 538, right? This is what the MATLAB documentation says, but since the image is 576*120 (as displayed in the window) this is not logical.
It seemed to me like, somehow, getPosition returns the y coordinate first. I need some clarification on this.
Thanks for help
I just tried running your code in MATLAB 7.8.0 (R2009a) and had no problems with image sizes of either 576-by-120 or 120-by-576 (I was unsure which orientation you were using). If I left click inside the image, it places a new movable point. It did not allow me to place any points outside the image.
One small bug I found was that if you left-click in the image, then drag the mouse pointer outside the image while still holding the left button down, it will place the movable point outside the image and won't display it, displaying a set of coordinates that are not clipped to the axes rectangle.
I'm not sure of what could be your problem. Perhaps it's a bug with whatever MATLAB version you are using. I would suggest either restarting MATLAB, or clearing all variables from the workspace (except for the image data im).
Might be worth checking to see which renderer you are using (Painter or OpenGL), a colleague showed me some wierd behaviour with point picking when using the OpenGL renderer which went away when using the Painter renderer.
Your code uses the Image Processing Toolbox, which I don't have, so this is speculation. The coordinate system is probably set to the figure window (or maybe even the screen), not the image.
To test this, try clicking points outside the image to see if you can find the origin.