pylegs.io.compress_fits_image#

compress_fits_image(file: str | Path | BytesIO, save_path: str | Path = None, overwrite: bool = True, compress_type: Literal['RICE_1', 'RICE_ONE', 'PLIO_1', 'GZIP_1', 'GZIP_2', 'HCOMPRESS_1', 'NOCOMPRESS'] = 'NOCOMPRESS', hcomp_scale: int = 3, quantize_level: int = 10, quantize_method: Literal[-1, 1, 2] = -1, tile_shape: Tuple[int, int] = None, dither_seed: int = 0, ext: int = 0)[source]#

Compress a FITS image and optionally save the compressed image to a file.

Parameters:

filePathOrFile: The path to the FITS file to be compressed. This can be a string or a pathlib.Path object.
save_pathstr or Path, optional: The path where the compressed FITS image will be saved. If None, the compressed image is not saved. Defaults to None.
overwritebool, optional: If True, overwrite the existing file at save_path. Defaults to True.
compress_typestr, optional: The compression algorithm to use. Supported values include 'HCOMPRESS_1', 'RICE_1', 'GZIP_1', 'PLIO_1'. Defaults to ‘HCOMPRESS_1’.
hcomp_scaleint, optional: The scale parameter for HCOMPRESS. Defaults to 3.
quantize_levelint, optional: The quantization level for compression. Defaults to 10.
quantize_methodint, optional: The quantization method to use. Defaults to -1.
extint, optional: The ext of the FITS file to compress. Defaults to 0.
random_seedint, optional: The seed for random number generation used in dithering. Defaults to 42.

Returns:

fits.CompImageHDU: The compressed image HDU.

Raises:

ValueError: If the specified FITS ext is out of range.

Notes

If save_path is provided and overwrite is True, the compressed image will be saved to the specified path. Otherwise, the function returns the compressed image HDU.

Examples

>>> compress_fits_image('input.fits', save_path='compressed.fits', compress_type='RICE_1')
<astropy.io.fits.hdu.compressed.CompImageHDU object at 0x...>

pylegs.io.compress_fits_image#

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