Optics

The PyColibri optics module encompasses a collection of optical systems extensively employed in the computational imaging research for spectral, depth, phase and other imaging applications. This module facilitates the simulation of optical propagation and the design of optical elements inside the systems, offering researchers and developers a powerful toolkit for advancing imaging technologies.

Mathematically, all implemented optical systems are of the form

\[\mathbf{y} = \forwardLinear_{\learnedOptics}(\mathbf{x}) + \noise\]

where \(\mathbf{x}\in\xset\) is the input optical field, \(\mathbf{y}\in\yset\) are the acquired signal, \(\forwardLinear:\xset\mapsto \yset\) is a deterministic (linear or non-linear) optics model of the acquisition system, \(\learnedOptics\) is a set of learnable parameters characterizing the optical system, and \(\noise\) is a stochastic mapping which characterizes the noise affecting the measurements.

Spectral Imaging systems

colibri.optics.cassi.SD_CASSI	Single Disperser Coded Aperture Snapshot Spectral Imager (SD-CASSI)
colibri.optics.cassi.DD_CASSI	Dual Disperser Coded Aperture Snapshot Spectral Imager (DD-CASSI)
colibri.optics.cassi.C_CASSI	Color Coded Aperture Snapshot Spectral Imager (C-CASSI)
colibri.optics.spc.SPC	Single Pixel Camera (SPC).
colibri.optics.doe.SingleDOESpectral	Single Diffractive Optical Element for Spectral Imaging

Functional operators of the optical systems

colibri.optics.functional.forward_color_cassi	Forward operator of color coded aperture snapshot spectral imager (Color-CASSI)
colibri.optics.functional.backward_color_cassi	Backward operator of color coded aperture snapshot spectral imager (Color-CASSI)
colibri.optics.functional.forward_dd_cassi	Forward operator of dual disperser coded aperture snapshot spectral imager (DD-CASSI)
colibri.optics.functional.backward_dd_cassi	Backward operator of dual disperser coded aperture snapshot spectral imager (DD-CASSI)
colibri.optics.functional.forward_sd_cassi	Forward operator of single disperser coded aperture snapshot spectral imager (SD-CASSI)
colibri.optics.functional.backward_sd_cassi	Backward operator of single disperser coded aperture snapshot spectral imager (SD-CASSI)
colibri.optics.functional.forward_spc	Forward propagation through the Single Pixel Camera (SPC) model.
colibri.optics.functional.backward_spc	Inverse operation to reconstruct the image from measurements.
colibri.optics.functional.psf_single_doe_spectral	Calculate the point spread function (PSF) of an optical system comprising a diffractive optical element (DOE) for spectral imaging.
colibri.optics.functional.convolutional_sensing	Simulate the convolutional sensing model of an optical system, using either Fourier or spatial domain methods.
colibri.optics.functional.fourier_conv	Apply Fourier convolution theorem to simulate the effect of a linear system characterized by a point spread function (PSF).
colibri.optics.functional.signal_conv	This function applies the convolution of an image with a Point Spread Function (PSF) in the signal domain.
colibri.optics.functional.wiener_filter	This function applies the Wiener filter to an image.
colibri.optics.functional.gaussian_noise	Add Gaussian noise to an image based on a specified signal-to-noise ratio (SNR).

Functional operators of optical elements

colibri.optics.functional.prism_operator	Prism operator, shifts linearly the input tensor x in the spectral dimension.
colibri.optics.functional.circular_aperture	Create a circular aperture mask of a given radius and pixel_size of size (M, N).
colibri.optics.functional.height2phase	Convert height map to phase modulation.
colibri.optics.functional.ideal_panchromatic_sensor	Simulate the response of an ideal panchromatic sensor by averaging the spectral channels.
colibri.optics.functional.wave_number	Wavenumber
colibri.optics.functional.get_spatial_coords	Generate the spatial coordinates for wave optics simulations in a specific coordinate system.

Functional operators of light propagation

colibri.optics.functional.scalar_diffraction_propagation	Compute the optical field propagation using a scalar diffraction theory model which is given by the specific approximation selected.
colibri.optics.functional.transfer_function_angular_spectrum	The transfer function for the angular spectrum propagation can be written as follows:
colibri.optics.functional.transfer_function_fresnel	The transfer function for the Fresnel propagation can be written as follows:
colibri.optics.functional.fraunhofer_propagation	The Fraunhofer approximation of \(U_0(x',y')\) is its Fourier transform, \(\mathcal{F}\{U_0\}\) with an additional phase factor that depends on the distance of propagation, \(z\).
colibri.optics.functional.fraunhofer_inverse_propagation	The inverse Fraunhofer approximation (to reconstruct the field at the source from the field at the sensor) is given by the following equation:

state-of-the-art optical elements

colibri.optics.sota_does.conventional_lens	Code to generate a conventional lens with a given focal length and radius following the equation
colibri.optics.sota_does.spiral_doe	Code to generate a spiral DOE with a given number of spirals, radius, focal length and wavelength range.

utils

colibri.optics.functional.add_pad	Add zero padding to a tensor.
colibri.optics.functional.unpad	Unpad a tensor.
colibri.optics.functional.fft	Fast Fourier Transform of an optical field
colibri.optics.functional.ifft	Inverse Fast Fourier Transform of an optical field