[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.


Christopher Barker, Ph.D.

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