Module azcam.fits

azcam.fits contains FITS image support functions for azcam.

Functions

def add(filename1: str, filename2: str, filename3: str, datatype: str = 'uint16') ‑> None

Add two images. filename3 = filename1 + filename2.

Args

filename1
image filename.
filename2
may be an image filename or a constant.
filename3
optional, must be an image filename. If not specified, result to filename1.
datatype
valid datatype string for resultant data type.
def add_history(filename: str, history_string: str, extension: int = 0) ‑> None

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.

Args

filename
image filename.
history_string
string to add as a HISTORY keyword.
extension
image extension number.
def arith(filename1: str, operator: str, filename2: str, filename3: str = '', datatype: str = 'uint16') ‑> None

Simple image arithmetic of FITS files.

Args

filename1
image filename.
operator
'+','-','/', or '*'.
filename2
may be an image filename or a constant.
filename3
optional, must be an image filename. If not specified, result to filename1.
datatype
valid datatype string for resultant data type.
def colbias(filename: str = 'test', fit_order: int = 3, margin_cols: int = 0) ‑> None

Remove column bias from a FITS file.

Args

filename
image filename.
fit_order
polynomial fit order, use 0 to remove median not fitted value.
margin_cols
number of overscan columns to skip before correction.
def combine(file_list: list = [], out_filename: str = 'combined.fits', combination_type: str = 'median', overscan_correct: int = 1, fit_order=3, datatype='float32') ‑> None

Make a combination iamge from a list of FITS filenames.

Args

file_list
list of filenames to combine.
out_filename
output filename.
combination_type
combination type, "median", "sum", or "mean".
overscan_correct
line fit order if >0 for overscan correction before combination.
def div(filename1: str, filename2: str, filename3: str, datatype: str = 'uint16') ‑> None

Divide two images. filename3 = filename1 / filename2.

Args

filename1
image filename.
operator
'+','-','/', or '*'.
filename2
may be an image filename or a constant.
filename3
optional, must be an image filename. If not specified, result to filename1.
datatype
valid datatype string for resultant data type.
def edit_keyword(filename: str, keyword: str, value: Any, extension: int = 0) ‑> None

Edits a header keyword value.

Args

filename
image filename.
keyword
keyword name.
value
new value of keyword.
extension
image extension number.
def file_exists(filename: str) ‑> bool

Args

filename
filename to check if exists.

Returns

True if the file exists.

def get_data(filename: str = 'test', roi: str = []) ‑> list

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

Args

filename
image filename.
roi
Region-Of-Interest.

Returns

list of pixel values.

def get_extensions(filename: str) ‑> list

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.

Args

filename
image filename.

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.

def get_header(filename: str, extension: int = 0) ‑> object

Return an image header.

Args

filename
image filename.
extension
image extension number.

Returns

the image header as a pyfits header object.

def get_history(filename: str, extension: int = 0) ‑> str

Returns the HISTOR header lines.

Args

filename
image filename.
extension
image extension number.

Returns

string containing all HISTORY lines.

def get_keyword(filename: str, keyword: str, extension: int = 0) ‑> Any

Return a header keyword value.

Args

filename
image filename.
keyword
keyword name.
extension
image extension number.

Returns

the specified keyword value.

def get_section(filename: str, section: str, extension: int = 0) ‑> list

Returns image section pixel numbers from a FITS keyword.

Args

filename
image filename.
section
section name (like "CCDSEC").
extension
image extension number where keyword is located.

Returns

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

def maximum(filename: str = 'test', roi: str = []) ‑> list

Compute maximum of an image ROI for every extension.

Args

filename
image filename.
roi
Region-Of-Interest.

Returns

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

def mean(filename: str = 'test', roi: list = []) ‑> list

Compute mean of an image ROI in every extension.

Args

filename
image filename.
roi
Region-Of-Interest.

Returns

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

def minimum(filename: str = 'test', roi: str = []) ‑> list

Compute minimum of an image ROI for every extension.

Args

filename
image filename.
roi
Region-Of-Interest.

Returns

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

def mult(filename1: str, filename2: str, filename3: str, datatype: str = 'uint16') ‑> None

Multiple two images. filename3 = filename1 * filename2.

Args

filename1
image filename.
operator
'+','-','/',or '*'.
filename2
may be an image filename or a constant.
filename3
optional, must be an image filename. If not specified, result to filename1.
datatype
valid datatype string for resultant data type.
def resample(filename: str, resample: int = 2) ‑> None

Resample an image by combining adjacent pixels.

Args

filename
image filename.
resample
number of pixels to combine in each dimension.
def sdev(filename: str = 'test', roi: list = []) ‑> list

Compute standard deviation of an image ROI in every extension.

Args

filename
image filename.
roi
Region-Of-Interest.

Returns

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

def stat(filename: str = 'test', roi: list = []) ‑> list

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

Args

filename
image filename.
roi
Region-Of-Interest.

Returns

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

def sub(filename1: str, filename2: str, filename3: str, datatype: str = 'uint16') ‑> None

Subtract two images. filename3 = filename1 - filename2.

Args

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