unique has an option to get indexes out which you can use in combination with sort to get the actual counts out.
tab0 = zeros( 256*256*256 , dtype=int) col=ravel(((im0[...,0].astype('u4')*256+im0[...,1])*256)+im0[...,2]) col,idx=unique(sort(col),True) idx=hstack([idx,[2500*2500]]) tab0[col]=idx[1:]-idx[:-1] tab0.shape=(256,256,256) As Chris pointed out, if each pixel were 4 bytes you could probably just use im0.view('>u4') for histogram values. //Torgil On Wed, Jan 18, 2012 at 10:26 AM, <a...@pdauf.de> wrote: > > Sorry, > > that i use this way to send an answer to Tony Yu , Nadav Horesh , Chris > Barker. > When iam direct answering on Your e-mail i get an error 5. > I think i did a mistake. > > Your ideas are very helpfull and the code is very fast. > > Thank You > > elodw > > > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion