https://groups.google.com/d/topic/pyqtgraph/ofKMx-oWbx8/discussion
On Thursday, October 11, 2018 at 3:52:45 PM UTC-4, [email protected] wrote: > > Hello, > > I have a problem when displaying an image having all its pixels forced at > the same value, for example 0. > This trivial example illustrates the problem : > > import numpy as np > import pyqtgraph as pg > > imageData = np.zeros(shape=(150,150), dtype=np.int) > pg.image(imageData) > > > The result is : > > runfile('C:/Users/Marc/.spyder-py3/temp.py', > wdir='C:/Users/Marc/.spyder-py3') > C:\Users\Marc\Anaconda3\lib\site-packages\pyqtgraph\graphicsItems\ImageItem.py:464: > > RuntimeWarning: invalid value encountered in double_scalars > bins = np.arange(mn, mx+1.01*step, step, dtype=np.int) > Traceback (most recent call last): > > File > "C:\Users\Marc\Anaconda3\lib\site-packages\pyqtgraph\graphicsItems\HistogramLUTItem.py", > > line 195, in imageChanged > h = self.imageItem().getHistogram() > > File > "C:\Users\Marc\Anaconda3\lib\site-packages\pyqtgraph\graphicsItems\ImageItem.py", > > line 464, in getHistogram > bins = np.arange(mn, mx+1.01*step, step, dtype=np.int) > > ValueError: arange: cannot compute length > > > Any idea on the way to solve this without disabling the nice histogram > functionality ? > My real application is displaying images updated slighly more than one > time per second, and sometimes a constant image is generated. > As a work around when I find such an image, I add a small value to one of > the pixels, but this is not a nice solution because the auto adujstment of > the luminance scale displays a white dot on a black image ;-) > > Marc > > -- You received this message because you are subscribed to the Google Groups "pyqtgraph" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/pyqtgraph/a3f19f18-b2a4-4043-ac7a-673e75c09307%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
