FITS Images

azcam.fits

azcam.fits contains FITS image support functions for azcam.

add(filename1, filename2, filename3, datatype='uint16')

Add two images. filename3 = filename1 + filename2.

Parameters:

Name	Type	Description	Default
filename1	str	image filename.	required
filename2	str	may be an image filename or a constant.	required
filename3	str	optional, must be an image filename. If not specified, result to filename1.	required
datatype	str	valid datatype string for resultant data type.	'uint16'

add_history(filename, history_string, extension=0)

Adds a HISTORY line containing 'history_string' to the image. Used to record actions performed on an image. A 20 character time stamp is added as a prefix, and the result is split across up to three cards if it is too long to fit in one. Any extra text is truncated.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	required
history_string	str	string to add as a HISTORY keyword.	required
extension	int	image extension number.	0

arith(filename1, operator, filename2, filename3='', datatype='uint16')

Simple image arithmetic of FITS files.

Parameters:

Name	Type	Description	Default
filename1	str	image filename.	required
operator	str	'+','-','/', or '*'.	required
filename2	str	may be an image filename or a constant.	required
filename3	str	optional, must be an image filename. If not specified, result to filename1.	''
datatype	str	valid datatype string for resultant data type.	'uint16'

colbias(filename='test', fit_order=3, margin_cols=0)

Remove column bias from a FITS file.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	'test'
fit_order	int	polynomial fit order, use 0 to remove median not fitted value.	3
margin_cols	int	number of overscan columns to skip before correction.	0

combine(file_list=[], out_filename='combined.fits', combination_type='median', overscan_correct=1, fit_order=3, datatype='float32')

Make a combination iamge from a list of FITS filenames.

Parameters:

Name	Type	Description	Default
file_list	list	list of filenames to combine.	[]
out_filename	str	output filename.	'combined.fits'
combination_type	str	combination type, "median", "sum", or "mean".	'median'
overscan_correct	int	line fit order if >0 for overscan correction before combination.	1

div(filename1, filename2, filename3, datatype='uint16')

Divide two images. filename3 = filename1 / filename2.

Parameters:

Name	Type	Description	Default
filename1	str	image filename.	required
filename2	str	may be an image filename or a constant.	required
filename3	str	optional, must be an image filename. If not specified, result to filename1.	required
datatype	str	valid datatype string for resultant data type.	'uint16'

edit_keyword(filename, keyword, value, extension=0)

Edits a header keyword value.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	required
keyword	str	keyword name.	required
value	Any	new value of keyword.	required
extension	int	image extension number.	0

file_exists(filename)

Parameters:

Name	Type	Description	Default
filename	str	filename to check if exists.	required

Returns: True if the file exists.

get_data(filename='test', roi=[])

Return data (pixel values) from an ROI in an image for every extension. NOT FINISHED!

Parameters:

Name	Type	Description	Default
filename	str	image filename.	'test'
roi	str	Region-Of-Interest.	[]

Returns: list of pixel values.

get_extensions(filename)

Returns the number of image extensions and their indices. The number of extensions is 0 for a standard FITS file and >0 for MEF. The first data extension for an MEF file is 1.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	required

Returns: the list [number_exts, first_ext, last_ext] containing the number of extensions and the indices for the python range function to iterate over them.

get_header(filename, extension=0)

Return an image header.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	required
extension	int	image extension number.	0

Returns: the image header as a pyfits header object.

get_history(filename, extension=0)

Returns the HISTOR header lines.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	required
extension	int	image extension number.	0

Returns: string containing all HISTORY lines.

get_keyword(filename, keyword, extension=0)

Return a header keyword value.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	required
keyword	str	keyword name.	required
extension	int	image extension number.	0

Returns: the specified keyword value.

get_section(filename, section, extension=0)

Returns image section pixel numbers from a FITS keyword.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	required
section	str	section name (like "CCDSEC").	required
extension	int	image extension number where keyword is located.	0

Returns: list of zero-based pixel numbers defining the section as [first_col,last_col,first_row,last_row].

maximum(filename='test', roi=[])

Compute maximum of an image ROI for every extension.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	'test'
roi	str	Region-Of-Interest.	[]

Returns: list of the maxima of each image extension or ROI in each extension.

mean(filename='test', roi=[])

Compute mean of an image ROI in every extension.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	'test'
roi	list	Region-Of-Interest.	[]

Returns: list of the means of each image extension or ROI in each extension.

minimum(filename='test', roi=[])

Compute minimum of an image ROI for every extension.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	'test'
roi	str	Region-Of-Interest.	[]

Returns: list of the minima of each image extension or ROI in each extension.

mult(filename1, filename2, filename3, datatype='uint16')

Multiple two images. filename3 = filename1 * filename2.

Parameters:

Name	Type	Description	Default
filename1	str	image filename.	required
filename2	str	may be an image filename or a constant.	required
filename3	str	optional, must be an image filename. If not specified, result to filename1.	required
datatype	str	valid datatype string for resultant data type.	'uint16'

resample(filename, resample=2)

Resample an image by combining adjacent pixels.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	required
resample	int	number of pixels to combine in each dimension.	2

sdev(filename='test', roi=[])

Compute standard deviation of an image ROI in every extension.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	'test'
roi	list	Region-Of-Interest.	[]

Returns: list of the standard deviations of each image extension or ROI in each extension.

stat(filename='test', roi=[])

Compute mean and sdev image statistics of ROI in every extension.

Parameters:

Name	Type	Description	Default
filename	str	image filename.	'test'
roi	list	Region-Of-Interest.	[]

Returns: list of [[means], [sdevs], ROI] for each image extension or ROI in each extension.

sub(filename1, filename2, filename3, datatype='uint16')

Subtract two images. filename3 = filename1 - filename2.

Parameters:

Name	Type	Description	Default
filename1	str	image filename.	required
filename2	str	may be an image filename or a constant.	required
filename3	str	optional, must be an image filename. If not specified, result to filename1.	required
datatype	str	valid datatype string for resultant data type.	'uint16'