When overlaying one image on another using hold on and transparency (the 'AlphaData' property), figure tools such as zooming in and the data cursor are not working properly.
This can be seen, for example, in the Marker-Controlled Watershed Segmentation example, by running ipexwatershed. The last figure of the example looks like this:
Using the zoom-in tool on the figure sometimes works, and sometimes results in an invisible figure, though the data is still there, as can be seen by using the data cursor. The data cursor itself behaves somewhat strangely, though it is usable. The black square and tooltip background of the cursor disappear, and only the text is seen.
This issue has already been raised on MATLAB Central a year ago, but no solution is provided there.
Related
I'm talking about the grid() command, not the previously asked and answered questions about showing lines around pixels (data cells). My image is of scientific data that has relevant axes and I would like the grid to overlay on the image plot. When I call grid(), the grid is there, but imagesc() covers it up. I can see it if I change the alpha of the image, but then the image looks grayed out. Is there another option?
EDIT: Here's an example of what I want. It turns out that it works just fine on my Windows machine, but my linux box shows no grid lines as described above. The linux machine uses software opengl. Any workarounds?
I recently came across a problem I can't solve which involves not being able to draw my sprites properly. I have tried a lot of different things and couldn't find any solution.
Here is how the image should look like in unity:
And here is how it actually looks like:
If someone could tell me how to fix this, I would be very grateful.
Presumably the top image is a screenshot of your image manipulation program, many of which use the chequerboard pattern to mean transparency. As such, the image you have exported is a gradient going from almost solid white at the bottom to transparent at the top. This is why the image appears as such in Unity.
Also, if you're wondering why the image appears as though it has bands of different colours, this is due to a problem called colour banding. This can be fixed by using a technique called Dither (which adds some noise to the image), but how you do so will depend on which image manipulation program you are using.
Context
Using the GUI Layout toolbox I have created an interface which basically is divided in two parts:
A toolbar area where the user selects the way he want to see data
A preview area to display data upon selected mode in the toolbar
For the preview area I used a uietxras.CardPanel object to switch between the view modes.
Problem
After some investigations, I discovered that if I display things in 3D (or 2D) in one of the preview card using surf (or pcolor) then it alters the display in the second card. If I display data in 1D only using plot commands I have not issue!
The issue I have when using pcolor/surf in one of the preview card:
Titles and labels seem to overlay in Preview 1
Axis borders are not displayed correctly in preview 2
Legend borders (when displayed) are altered also
If I only use plot commands in both preview modes I have no issue at all and cards are switching nicely.
Test case
My real code is really long, I have thus reduced it to the minimum so you can reproduce the issue:
https://gist.github.com/CitizenInsane/54f3c1eba2293d0e5264#file-guilayoutbug-m
Simply run the code and check the checkbox "Do 3D plot in preview 1" to see the issue happening when switching between the two preview modes:
Notes
As far I know, I'm using latest version of the GUI Layout toolbox (1.17).
I'm using R2013b for Matlab
I came across this issue as well. I'm afraid I never quite worked out what the cause was exactly, and it didn't appear in a very consistent way. The issue seems to be that plots on non-selected cards are not hidden properly, and get overlaid just behind and around the edges of the plots on the selected card.
I would encourage you to raise the issue with the authors of GUI Layout Toolbox via the comments on the toolbox's page at MATLAB Central, as I do think it's a bug.
Nevertheless, the reason I never followed it up myself is that I found a fairly straightforward workaround, which may also work for you. Each time the selected card is changed, I ran a simple function that deleted all children of all cards, and then re-plotted whatever I wanted on the selected card. It seemed a bit annoying to have to do that, but it worked, and removed any of the display issues you've come across.
Ok got it, the issue has nothing to do with CardPanel themselves, it is linked to the renderer of the figure.
Trying simple code below:
figure(42);
subplot(1,2,1);
plot(rand(1,12));
subplot(1,2,2);
peaks;
shading flat;
If the figure's renderer is set to 'OpenGL' (the default) ==> there are some glitches:
If the figure's renderer is set to 'zbuffer' ==> there is no glitch:
Setting the renderer to 'zbuffer' fixes the problem.
NB: Maybe OpenGL rendering can be fixed by fine tuning graphic card acceleration settings, but I don't know ... I issued opengl software and opengl hardware commands in Matlab and software rendering is worst than hardware rendering on my machine.
EDIT: Side notes
Transparency effects are only available if the renderer is set to 'openGL'. It is thus not possible to visualize at the same time both 1D and transparent-3D data without glitches (at least with hg version 1 in R2013b).
HG2 has no issue:
I need to segment an image in ios for a fashion app by keeping only the foreground image and removing all other background part of the image which should resemble like a tool for removing the background of images in various photo editing tools please help me.
General background subtraction is an unsolved problem, so getting perfect results is going to be a big effort. With that said, you can probably get close. Here are a couple of suggested avenues:
I am guessing that your app will place clothes on a human, or something of the sort. Instead of getting a perfect segmentation, run a person detector, remove all of the image except for the detected person, and fit a part-based human model to the remaining image. Then you have the pose of the person, and can do your image processing accordingly.
Allow the user to input some strokes from the foreground and some strokes from the background, and run a graph-cuts-based image segmentation algorithm on the frame.
Begin your process by having the user not be present in your video stream. From this, learn the background distribution (start with a simple histogram of background pixels, there are much more elaborate schemes but you need a starting place). Then, when the user enters the scene, create a binary image containing the connected components that don't fit into the learned background distribution. This will not be perfect, but you will start to see something close to a binary image where the white pixels are your user, and the black pixels are the background. Use morphology operators to join any large connected components that are slightly separated, and threshold your image to remove small noise in the image, from things like specular objects and illumination changes.
Like I said (and is mentioned in the comments), this is not an easy problem, but you can come up with a good approximation if you put some time into it. I suggest the third method I listed. It is achievable, and can be broken down into small parts so you can tell when you're making progress.
Good luck!
Any ideas why this page: http://mpdteam.net/projects.html is flashing when it scrolls? I've determined it's due to the background of the main content container, but why? is it a eye-trick, an image flaw, a browser flaw, or a code flaw? The code is easily viewable with view source or dev tools.
Let me know if you need anymore info. thanks.
(also, feel free to re-tag. i'm having a mind-blank for good tags)
It's because it uses finely spaced grey and white lines.
It is perhaps an example of the Moiré pattern, although this is more typically reserved for two overlapping grids at different angles.
I always assumed on a PC this occurred because of the redraw time between the two colours, and how finely spaced the lines are. The lines not perfectly aligning with pixels (e.g. anti-aliasing) would further enhance the flickering effect.
To fix it, try changing the size of the bands (e.g. try zooming out or in on the current page, and moving the browser, and note how you get reduced and even none of the described flickering effect).
Alternatively, you may want to apply a blur such that the difference between bands was softened (not sure if this would necessarily help).
Another suggestion that research yields is that it is due to background redrawing/scaling. However, a fixed background (as compared to a repeating one) isn't particularly applicable to your page.
In any case, for an in-depth discussion of some of the concepts involved, check out this awesome page (http://www.techmind.org/lcd/)