httm.data_structures.raw_converter

This module contains data structures for dealing with converting raw images to calibrated images.

class SingleCCDRawConverter[source]

An immutable object for managing a transformation from a raw FITS image into a calibrated image.

Parameters:
class SingleCCDRawConverterFlags[source]

Flags indicating which raw transformations have been performed.

Parameters:
  • smear_rows_present (bool) – Flag indicating whether there is data in the smear rows. Default: True
  • undershoot_present (bool) – Flag indicating whether undershoot is present or otherwise compensated for. Default: True
  • pattern_noise_present (bool) – Flag indicating whether pattern noise is present or otherwise compensated for. Default: True
  • start_of_line_ringing_present (bool) – Flag indicating whether start of line ringing is present or otherwise compensated for. Default: True
  • baseline_present (bool) – Flag indicating whether a baseline electron count is present or otherwise compensated for. Default: True
  • in_adu (bool) – Flag indicating whether the data is in Analogue to Digital Converter Units or otherwise in electron counts. Default: True
class SingleCCDRawConverterParameters[source]

Converter parameters for converting a raw FITS image into a calibrated FITS image.

Constructed using raw_converter_parameters_from_fits_header().

Parameters:
  • number_of_slices (int) – The number of slices to use in the transformation, either 1 or 4. Default: 4
  • camera_number (int) – The number of the camera that took the image. For real images, the serial number 0-31 of the FPE interface board is used. Default: -1
  • ccd_number (int) – The number of the CCD that took the image. Default: -1
  • number_of_exposures (int) – The number of frames stacked in the image. Default: 1
  • video_scales (tuple of float objects, must have one for each slice) – The video scaling constants, for converting back and forth between Analogue to Digital Converter Units (ADU) to electron counts. These have units of electrons per ADU. Default: (5.5, 5.5, 5.5, 5.5)
  • early_dark_pixel_columns (int) – Count of columns of pixels that have never traversed the image area or frame store, and thus were never exposed to light. Read before the image pixels in the row, these are where most of the start of line ringing may be seen. Default: 11
  • late_dark_pixel_columns (int) – Count of columns of pixels that have never traversed the image area or frame store, and thus were never exposed to light. Read after the image pixels in a row. Default: 11
  • final_dark_pixel_rows (int) – Count of rows of pixels that have traversed the frame store area, but not the image area, and thus were never exposed to light. Default: 10
  • smear_rows (int) – Count of rows of pixels that have traversed the imaging area during frame transfer, but have zero exposure to light otherwise. These are for estimating the effect of smear on the imaging pixels. Default: 10
  • gain_loss (float) – The relative decrease in video gain over the total ADC range. This is the parameter of the non-linearity model. This is sometimes referred to as compression in electrical engineering literature. Default: 0.01
  • undershoot_parameter (float) – The deficit in a pixel value relative to the value of its preceding pixel. This is a ratio and dimensionless. The electronics have a slight memory of the signal level which cause the pixel following a bright pixel to appear slightly darker that it should. Default: 0.0013
  • pattern_noise (str) – A matrix to be read from a FITS file (either uncompressed or compressed with gzip, bzip2, or pkzip), representing the repeatable change in the video baseline caused by the disturbance in the data acquisition rhythm between frames. Organized as a RAW FFI (including dark pixels and smear rows), in Analogue to Digital Converter Units (ADU). Default: built-in simulated_pattern_noise.fits