[Numpy-discussion] first recarray steps

Christopher Barker Chris.Barker@noaa....
Tue May 20 11:08:26 CDT 2008



Vincent Schut wrote:
> Lets say I have a rgb image of arbitrary size, as a normal ndarray 
> (that's what my image reading lib gives me). Thus shape is 
> (3,ysize,xsize), dtype = int8. How would I convert/view this as a 
> recarray of shape (ysize, xsize) with the first dimension split up into 
> 'r', 'g', 'b' fields? No need for 'x' and 'y' fields.

Take a look in this list for a thread entitled "recarray fun" about a 
month ago -- you'll find some more discussion of approaches.

Also, if you image data is rgb, usually, that's a (width, height, 3) 
array: rgbrgbrgbrgb... in memory. If you have a (3, width, height) 
array, then that's rrrrrrr....gggggggg......bbbbbbbb. Some image libs 
may give you that, I'm not sure.

Also, you probably want a uint8 dtype, giving you 0-255 for each byte.

-Chris



-- 
Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R            (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chris.Barker@noaa.gov


More information about the Numpy-discussion mailing list