FAQ Database Discussion Community

## spread imshow heatmap over limits of axis

python,matplotlib,imshow
I have an array of x,y positions at one time step and but I know over time this range will expand (as set by the image range already). Is there a way to make the rest of the grid over the range be 0 until it is populated. My understanding...

## Assign the Window centre and window width for dicom image

matlab,image-processing,dicom,imshow
I have a Dicom image file in dcm format.In matlab by using Dicomread i got image data and by using dicominfo i got window center and window width of that dcm file. Now i want to display the image by using imshow in figure. My code is below, ct =...

## Can't use imshow in xcode 5 on OSX 10.8

c++,xcode,osx,opencv,imshow
I'm kind of puzzled as I cannot use imshow from the opencv library. I use plenty of other function from opencv, but I get this error, when I want to show my matrix/image. Undefined symbols for architecture x86_64: "cv::namedWindow(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, int)", referenced from: _main in main.o "cv::imshow(std::__1::basic_string<char,...

## Basemap Heat error / empty map

python,data,matplotlib,matplotlib-basemap,imshow
I am trying to plot a scattered heat map on a defined geo location. I can very well plot a normal scattered map with no background but I want to combine it with a given lat and lon. I get the following empty map. Input Input: col[2] and col[3] are...

## Rebin data and update imshow plot

python,numpy,matplotlib,draw,imshow
I have a large data set I want to be able to "zoom" in on. What I really want is for the data to be rebinned based on the selection and then update the data in the graph. So the graph will show different limits but maintain the same resolution....

## How to apply the OpenCV-function polylines() to lists in C++

c++,list,opencv,imshow
I have a result like this std::list<std::list<cv::Point2i>> and I would like to visualize the result using polylines() and imshow(). Is there a way to realize this without having to copy the list elements to vectors?

## Matlab make half of the image blank

Got an issue on matlab, trying to make half of the image blank without resizing to it. ATM im using that simple code im=imread('spinpie.bmp'); n=fix(size(im,1)/2); A=im(n+1:end,:,:); imshow(A) And im geting this: What is actually i need to have is something like this: Ty...

## matplotlib.pyplot.imshow() shows blank canvas

matplotlib,imshow
I've come across an oddity that the internet hasn't been able to solve so far. If I read in a .png file, then try to show it, it works perfectly (in the example below the file is a single blue pixel). However, if I try to create this image array...

## Python - Add annotation in subplot imshow

python,matplotlib,annotations,imshow
I would like to add some annotations on a figure with multiple subplots...On the figure below i would like to write something below the 2 right figures and at the left top. How can i do that? I try with : ax3.text(0.1, 0.5, '$\sigma =$' resV.mean(), size=12, ha='center', va='center') But...

## matplotlib gui imshow coordinates

python,matplotlib,pyqt4,imshow
I'm making a GUI using pyqt4 which contains an image displayed by matplotlib's imshow using a 2d array. If I displayed this with pyplot, the window would show the x, y coordinates of the cursor if I move the mouse over the image. However, this seems to have disappeared when...

## Issue in Refresh CData of HGimage

matlab,imshow
Initially I am create a figure in GUI with two button (btnStart , btnNext ) and one axes (P_axes). For above two buttons I am using callback function. In first button callback Function function btnStart_callback(hObject,eventdata ,handles) load MRI; d = D(:,:,1); handles.Img = imshow(d,'Parent' , P_axes); setappdata(handles.figure1 , 'Indx' ,...

## how to remove “empty” space between subplots?

python,matplotlib,plot,subplot,imshow
I'm making a figure with a total of 68 subplots and want to remove the empty space between them all. Here's what I have: . How would I go about doing this? EDIT: using plt.tight_layout() makes it even worse: Here's my code: for j in range(0,len(sort_yf)): for i in range(0,len(yf)):...

## python matplotlib, get pixel value after colormap applied

python,matplotlib,imshow
I display an image with matplotlib using imshow(). imshow apply a LUT and I would like to retrieve a pixel value (at x, y) after LUT applied. For exemple I have a full black image I display with imshow The image becomes yellow (cause of LUT) get_pixel(x, y) -> yellow...