Some simple image filters by convolution in Python and OpenCL
71 mins
This short article contains a summary about image filters and how one can realize them. It will contain a short reminder of how convolution works, what separable filters are and some example of image filters and their (most inefficient but direct) implementation in Python. In the end it will also show how one might naively implement convolution in OpenCL to increase performance in comparison to the naive Python implementations shown. This article provides one with a small playground to quickly try out separable image filter kernels and execute them on the GPU using pyopencl from a Python testing environment.
Towards Driving Quantum Systems in Cryogenic Environments with the Near-Field of Modulated Electron Beams
1 min
Presented at the 13th ASEM (Austrian Society for Electron Microscopy) workshop: Coherent electro-magnetic control of quantum systems is usually done by electro-magnetic radiation - which limits addressing single selected quantum systems, especially in the microwave range. In our proof of concept experiment we want to couple for the first time the non-radiative electro-magnetic near-field of a spatially modulated electron beam to a quantum system in a coherent way. As the quantum system we use the unpaired electron spins of a free radical organic sample (Koelsch radical - α, γ-Bisdiphenylene-β-phenylallyl) that is excited via the near-field of the modulated electron beam. The readout of the spin excitation resembles a standard continuous wave electron spin resonance experiment and is done inductively via a microcoil using a lock-in amplifier. In the long term this experiment should demonstrate the feasability of coherent driving and probing of quantum systems far below the diffraction limit of electro-magnetic radiation by exploiting the high spatial resolution of an electron beam.
Using pycryptodomex for encryption and signing (PKCS1 OAEP and PSS) in Python
18 mins
This is a short summary or rather recipe collection on how to use ```pycryptodomex``` for some simple encryption and decryption procedures using RSA with the OAEP schemes from ```PKCS#1``` as well as signing and verification routines using the PSS scheme.
Running JupyterLab behind an authenticating haproxy setup using basic auth
9 mins
The journey of getting a JupyterLab instance running behind a haproxy reverse proxy on Manjaro Linux and FreeBSD - with some drawbacks.
Hosting your own GIT large file storage repositories
10 mins
Short introduction into gits large file storage extension, the way it works and how to run it without an external provider to host your files
Getting started with WSGI and Python as well as uwsgi application server
20 mins
A simple summary of hat WSGI can do for one, how to use it with Python and how to run the uwsgi application server (and how to solve the deployment problem there) from the viewpoint of someone who already developed web applications in many different languages and frameworks.
Using the FY6900 with an external USB to serial bridge
6 mins
Short article about circumventing the CH340 contained in the FY6900 function generator by using its external 3.3V serial interface and an CP2102 or any microcontroller.
Detecting frequency, delay and phase relation as well as multiple targets using correlation functions
15 mins
A short story about how one can use autocorrelation and cross-correlation functions on discretized samples of radio frequency data and also noise to detect the frequency of a single signal, the delay of a reflected signal, the phase relation between two signals and how one can track multiple reflective targets in applications like LIDAR, sonar or radar using correlations - and how to get them robust against external influence.
Heterodyne, Superheterodyne, Homodyne and Lock-In Amplifier
14 mins
A mini introduction about the terms heterodyne, superheterodyne, homodyne and lock-in amplifier
Simple time lapse with ffmpeg
4 mins
Short summary on how to generate time lapse videos from webcams or other sources using ffmpeg on various platforms
