This project aims to democratize physical and mathematical concepts that various industries uses to design optical systems, from smartphones to Eath Observation satellites.
With this python project, the user could:
- Simulate different optical systems, as telescopes or lenses, with key parameters, i.e. aperture radius, secondary mirror obstruction, focal length, pixel size, light wavelength.
- Generate optical quality metrics visualizations, i.e. Point spread Function, Modulation Transfer Function.
- Add and understand optical aberrations which are inherent to any acquisition system manufacturing.
In this project we are using physical and mathematical concepts developped and improved since Thomas Young's interference experiment described in his paper in 1801 On the theory of light and colours where he illustrated the wave property of light, , enriching Isaac Newton' s corpuscular theory of light.
Young' s illustration on light interference, light propagation through a partially obstructed plane, F. Zernike' s illustration of optical aberration
From Joseph von Fraunhofer who helped to modelize the propagation of the light for far field, as a wave, through a partly blocked plane, with the Fraunhofer diffraction equation. To Frits Zernike, who was awarded with the Nobel Prize for Physics in 1952 for his work on modelizing optical aberrations through phase contrast polynomial. The code is mainly based on those 3 scientific papers / books:
- To simulate light diffraction, Modeling the Imaging Chain of Digital Cameras
- To test that the algorithms modelize correctly the physical phenomena, The Use Of Image Quality Criteria In Designing A Diffraction Limited Large Space Telescope
- To add optical aberrations with the simple and beautiful Zernike polynomial, Zernike F, The Diffraction Theory of Aberrations, in Optical Image Evaluation Circular 526, ( National Bureau of Standards , Washington, D. C), 1952
As a recommendation, you could install this project with a virtual environment as venv
git clone https://github.com/flp3/Simulator-of-Optical-Quality.git
cd Simulator-of-Optical-Quality
pip install virtualenv
python -m venv venv
venv\Scripts\activate
pip install .For anyone interested into simulating and getting nice visualization without getting into the code, you could find the command line interface useful: cli.py
Some nice commands are already deployed:
python .\src\cli.py --helpOptions:
-h, --help Show this message and exit.
Commands:
visualize-aberrations visualize the optical aberrations
visualize-apertures visualize the instrument aperture
visualize-diffraction visualize the light diffraction through an aperture
visualize-system-with-aberrations visualize the light propagation through an
acquisition system with optical aberrationsFor example we could
- visualize the impact of different optical aberrations on the light' s phase as a wave passing through an open disk (as a lens):
python .\src\cli.py visualize-aberrations --zernike_azimuth 2 --zernike_radial 2
- visualize the light propagation through a lens of 15mm of radius with some defocus aberration and see the Point spread function, and its Modulation function:
python .\src\cli.py visualize-system-with-aberrations l --radius 15 --wavelength 800e-9 --focal_length 0.1 --pixel_size 1.5e-6
- Simulate the image quality of a Cassgrain Telescope satellite, at 500km altitude orbit, capturing image of the earth with a ground sampled distance of 0.85m per pixel, and a bit of alisaing as the MTF at Nyquisit, i.e. the sampling frequency, would be around 10-15% with some optical aberrations:
python .\src\cli.py visualize-system-with-aberrations t --radius 150 --wavelength 800e-9 --focal_length 2.3 --pixel_size 4e-6