Detector classes¶
Detector classes have not yet been integrated into the Skimpy framework. However these classes provide useful information about detectors.
DetectorProperties¶
The base class for detectors.
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class
DetectorProperties¶ -
__init__()¶ Initialize self. See help(type(self)) for accurate signature.
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dark_signal_rate(ccd_temperature: float) → float¶ Returns the dark current of the detector at the given temperature in electrons per second .
- Parameters
ccd_temperature (float) – Temperature of the detector in Kelvin
Returns (return:) –
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model_noise_snr(photon_flux: numpy.ndarray, wavelength: float, exposure_time: Union[float, numpy.ndarray], ccd_temperature: Optional[float] = None, num_offchip_pixels: Optional[int] = None, num_onchip_pixels: Optional[int] = None) → float¶ Models the signal to noise ratio after accounting for dark current, quantum efficiency and detector readout. The default implementation is appropriate for CCD technologies where the error is Poisson shot noise and has both CCD readout noise and electronics noise (digitization errors etc.). Other tytpes of detector should override this default method.
- Parameters
photon_flux (np.ndarray(NSamples)) – The array of photon fluxes for all the samples of one pixel. This signal has been integrated over the field of view, wavelenghth bandpass and front aperture area and provides photons per second.
wavelength (float) – The nominal wavelength of the photon fluxes. This is usually the central wavelength of the pixel and is used to apply the quantum efficiency of the detector.
exposure_time (float or np.ndarray(Nsamples)) – Optional. Default 1.0. The exposure time of each photon flux sample in seconds. It can be a scalar or it must be an array the same size as photon_flux.
ccd_temperature (float) – Optional, The temperature of the CCD in Kelvin. This value is simply passed on to method
dark_signal_rate. Default is normally taken from current detector attributes.num_offchip_pixels (int) – Optional. The number of off-chip pixels to sum over. Default is taken from current detector attributes.
num_onchip_pixels (int) – Optional. The number of on-chip pixels to sum over. Default is taken from current detector attributes.
- Returns
The signal-to-noise ratio. (Signal/Noise).
- Return type
float
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quantum_efficiency(wavelength: Union[float, numpy.ndarray]) → Union[float, numpy.ndarray]¶ Returns the detector quantum efficiency at the given wavelength. This simply looks up the the quantum efficiency table in the detector attributes and performs a linear interpolation in wavelength.
- Parameters
wavelength (float or np.ndarray) –
- Returns
The quantum efficiency of the detector at the given wavelengths
- Return type
float or np.ndarray
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DetectorProperties_GT4095¶
This is a descriptrion of the Allied Vision GT4095 CCD detector. This detector was used on the 2018 CATS instrument.
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class
DetectorProperties_GT4095¶ Properties of the Allied Vision GT4095 camera. Note that the sensor in this camera is a KAI-16050. Some of the specs come from Allied Vision datasheets, some come from KAI datasheets. I think some of the values are also just wrong and should be checked out.
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__init__()¶ Initialize self. See help(type(self)) for accurate signature.
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dark_signal_rate(ccd_temperature: Optional[float] = None)¶ Returns the dark current of the detector at the given temperature in electrons per second .
- Parameters
ccd_temperature (float) – Temperature of the detector in Kelvin
Returns (return:) –
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