Re: [Matplotlib-users] weird matplotlib imread question for png

[oyster <lep...@gm...>]

Two 8bpp(Gimp, xnview say so) graylevel png files can be downloaded
The first (ramp-gray.png) which gives right array shape is
http://bbs.blendercn.org/data/attachment/forum/201504/17/090627ejhixti8vdthdnnn.png
The second one (python-gray.png) which gives 'wrong' array shape, at
least to me, is
http://bbs.blendercn.org/data/attachment/forum/201504/16/222351w3952n3o9968m9a5.png

[code]
from pylab import *

imgRampPng=imread('ramp-gray.png')
print (imgRampPng.shape)   #(1, 255), that is right
print (imgRampPng.min(),imgRampPng.max()) #(0.0, 0.99607843)
print ()

imgGrayPng=imread('python-gray.png')
print (imgGrayPng.shape)    #(128, 128, 3), *but I suppose it should
be (128, 128)*
print (imgGrayPng.min(),imgGrayPng.max())   #(0.0, 0.98823529)
print ()
Ch1=imgGrayPng[:,:,0]
Ch2=imgGrayPng[:,:,1]
Ch3=imgGrayPng[:,:,2]
print (Ch1.min(), Ch1.max())    #(0.0, 0.98823529)
print (Ch2.min(), Ch2.max())    #(0.0, 0.98823529)
print (Ch3.min(), Ch3.max())    #(0.0, 0.98823529)  #that is to say,
Ch1/2/3 hold same data
print ()
[/code]