Viewer does not display non-zero pixels

[vgenty]

Yikes! Ariana found that the viewer may not display all non-zero pixels in the image when using user-controlled thresholding. Here is an example of a Nu in plane 1, with auto pyqtgraph intensity scale (that's why is looks like shit)

Set the imin threshold a little higher than 0, and there are non-zero pixels in the image if you slice on it the values are...
[ 2.50050282 2.87391782 2.25792432 3.22080231 3.17725968 1.86988342 1.64758134 3.24257207 2.84999657 2.88998723 3.7988553 1.76502311 1.17307568 4.05927277 1.23509991 1.21503234 4.26263475 4.66946697 1.23992372 4.14212132 2.64220333 3.4762044 3.35693979 3.57622218 3.47608447 3.77681541 3.72539306 4.3190136 3.80827284 1.18566716 5.65644979 3.04839444 2.34159589 8.38000679 1.78434169 1.01273596]

but the image is blank...

quick fix is to artificially boost the pixel values by 100 with
self.plot_mat*=100.0 placed on line 124 in

https://github.com/LArbys/LArCV/blob/master/mac/pyrgb/lib/image_types/plotimage.py

Now with an appropriate threshold, we see the pixels appear

I see 7 non zero pixels and it's confirmed on the slice
[ 4.05927277 4.26263475 4.66946697 4.14212132 4.3190136 5.65644979 8.38000679]

I've tried a number of things to get the pixels to scale which include

• pyqtgraph.ImageItem.setLevels
• opacity=1.0 in setImage function
• setCompositionMode to QtGui.QPainter.CompositionMode_Plus (Both the alpha and color of the image and background pixels are added together.)

but so far an arbitrary scaling has resolved this. I will leave this open until I find a better way to address.

[twongjirad]

This is definitely a strange bug. I see that, at least on my computers, the version of pyqtgraph I am using 0.9.8 is old. There is 0.9.10. In version 0.9.9 there are options for downsampling techniques. Maybe this miraculously addresses this.

[vgenty]

@ahack379 did we get this resolved?