SPIDER

PIL reads and writes SPIDER image files of 32-bit floating point data (“F;32F”).

PIL also reads SPIDER stack files containing sequences of SPIDER images. The seek and tell methods are supported, and random access is allowed.

The open method sets the following attributes:

format

Set to ‘SPIDER’

istack

Set to 1 if the file is an image stack, else 0.

nimages

Set to the number of images in the stack.

A convenience method, convert2byte, is provided for converting floating point data to byte data (mode “L”):

im = Image.open('image001.spi').convert2byte()

Writing files in SPIDER format

The extension of SPIDER files may be any 3 alphanumeric characters. Therefore the output format must be specified explicitly:

im.save('newimage.spi', format='SPIDER')

For more information about the SPIDER image processing package, see the SPIDER home page at Wadsworth Center.