Chip

class simcado.detector.Chip(x_cen, y_cen, x_len, y_len, pix_res, pixsize=15, angle=0, gain=1, obs_coords=[0, 0], fieldangle=0, chipid=None, flat_field=None)

Bases: object

Holds the “image” as seen by a single chip in the focal plane

The Chip object contains information on where it is located in the focal plane array. The method <Source>.apply_optical_train() passes an image of the on-sky object to each Chip. This image is resampled to the Chip pixel scale. Each Chip holds the “ideal” image as an array of expectation values for number of photons arriving per second. The Chip then adds detector noise and other characteristics to the image when <Detector>.readout() is called.

Parameters

x_cen, y_cenfloat

[micron] the coordinates of the centre of the chip relative to the centre of the focal plane

x_len, y_lenint

the number of pixels per dimension

pix_resfloat

[arcsec] the field of view per pixel

idint

an identification number for the chip (assuming they are not correctly ordered)

flat_fieldnp.ndarray

a 2D array holding the flat fielding effects for the chip

See also

Detector

simcado.source.Source

simcado.commands.UserCommands

simcado.optics.OpticalTrain

Attributes

x_cen, y_cenfloat

[arcsec] the coordinates of the centre of the chip relative to the centre of the focal plane

naxis1, naxis2int

the number of pixels per dimension

pix_resfloat

[arcsec] the field of view per pixel

chipidint, optional

the id of the chip relative to the others on the detector array. Default is None

dx, dyfloat

[arcsec] half of the field of view of each chip

x_min, x_max, y_min, y_maxfloat

[arcsec] the borders of the chip relative to the centre of the focal plane

arraynp.ndarray

an array for holding the signal registered by the Chip

Methods

add_signal(signal)	adds signal to .array. The signal should be the same dimensions as Chip.array
add_uniform_background(emission, lam_min, lam_max, output=False)	adds a constant to the signal in .array. The background level is found by integrating the emission curve between lam_min and lam_max. If output is set to True, an image with the same dimensions as .array scaled to the background flux is returned.
apply_pixel_map(pixel_map_path=None, dead_pix=None, max_well_depth=1E5)	applies a mask to .array representing the position of the current “hot” and “dead” pixels / lines
reset()	resets the signal on the Chip to zero. In future releases, an implementation of the persistence characteristics of the detector will go here.

Methods Summary

add_signal(self, signal)	Add a 2D array of photon signal to the Chip
add_uniform_background(self, emission, …)	Add a uniform background
apply_pixel_map(self[, pixel_map_path, …])	Adds “hot” and “dead” pixels to the array
read_out(self, cmds[, read_out_type])	Read out the detector array
reset(self)

Methods Documentation

add_signal(self, signal)

Add a 2D array of photon signal to the Chip

Add some signal photons to the detector array. Input units are expected to be [ph/s/pixel]

Parameters

signalnp.ndarray

[ph/pixel/s] photon signal. signal should have the same dimensions as the array

Returns

None

add_uniform_background(self, emission, lam_min, lam_max, output=False)

Add a uniform background

Take an EmissionCurve and some wavelength boundaries, lam_min and lam_max, and sum up the photons in between. Add those to the source array.

Parameters

- emission_curve: EmissionCurve object with background emission photons

- lam_min, lam_max: the wavelength limits

Optional keywords:

- output: [False, True] if output is True, the BG emission array is

returned

Output is in [ph/s/pixel].

apply_pixel_map(self, pixel_map_path=None, dead_pix=None, max_well_depth=100000.0)

Adds “hot” and “dead” pixels to the array

applies a mask to .array representing the positions of the current “hot” and “dead” pixels / lines. The method either reads in a FITS file with locations of these pixels, or generates a series of random coordinates and random weights for the pixels.

Parameters

pixel_map_pathstr

path to the FITS file. Default is None

dead_pixint

[%] the percentage of dead or hot pixels on the chip - only used if pixel_map_path = None. Default is None.

max_well_depth1E5

Returns

None

read_out(self, cmds, read_out_type='superfast')

Read out the detector array

Parameters

cmdssimcado.UserCommands

Commands for how to read out the chip

Returns

out_arraynp.ndarray

image of the chip read out

reset(self)