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iofits

Convert FITS files from one pixel depth to another (without rescaling).

iofits converts FITS files from one pixel depth to another. The pixels are just converted from one data type to the other, without interpretation of their values. Intrinsic problems for such a utility are:

• Converting from n to p bits per pixel means a probable loss of data whenever p<n.
• Converting pixels without scaling means there is some value clipping. Example: converting float pixels in the interval [-32000..+43000] to an 8-bit image would produce pixels in [0..255] with all negative input pixels clipped to zero and all input pixels above 255 clipped to 255.

Beware that no interpretation is done of the BSCALE and BZERO keywords. Pixel values are converted as they are in the file, not as they should be interpreted with these keywords set to anything else but resp. 1 and 0. The initial FITS header is copied, only the BITPIX value is modified.

• iofits manual page
• iofits.c

Send comments to catalog@eso.org Last modified: Tue Aug 6 11:08:05 MEST 2002