Author Archives: bartwronski

Separate your filters! Separability, SVD and low-rank approximation of 2D image processing filters

Posted on February 3, 2020

In this blog post, I explore separable convolutional image filters: how can we check if a 2D filter is separable, and how to compute separable approximations to any arbitrary 2D filter represented in a numerical / matrix form using SVD. Continue reading →

Posted in Code / Graphics | Tagged algorithms, approximation, blur, bokeh, depth of field, graphics, image processing, linear algebra, numpy, optimizations, postprocessing, python | 3 Comments

Analyze your own activity data using Google Takeout – music listening stats example

Posted on January 6, 2020

The goal of this post is to show how to download our own data stored and used by internet services to generate personalized stats / charts like below and will show step-by-step how to do it using colab, Python, pandas, … Continue reading →

Posted in Code / Graphics | Tagged colab, data, numpy, programming, python, statistics, visualization | Leave a comment

Local linear models and guided filtering – an alternative to bilateral filter

Posted on September 22, 2019

Intro In this blog post I am going to describe an alternative tool for the graphics and image processing programmers’ toolbox – guided filtering. Guided filtering is a really handy tool that I learned about from my coworkers, and I … Continue reading →

Posted in Code / Graphics | Tagged bilateral, graphics, image processing, machine learning, postprocessing, python, signal processing, ssao, upsampling | 2 Comments

How (not) to test graphics algorithms

Posted on August 14, 2019

Intro Siggraph 2019 is sadly over, but as always I came back super inspired and grateful for meeting many friends. Conferences are mostly not about seeing the presentations – but about all the interesting and inspiring discussions, and one of … Continue reading →

Posted in Code / Graphics | Tagged code design, code style, graphics, graphics programming, programming, siggraph, testing, tests | 2 Comments

Checkerboard rendering, rotated anti-aliasing and grid frequencies

Posted on May 14, 2018

This post is inspired by three interesting statements or questions that I heard and are interconnected by non-obvious theory: First was regarding so called checkerboard rendering (example1 example2) – what is advantage of using it? After all it’s the same as … Continue reading →

Posted in Code / Graphics | Tagged antialiasing, fourier, frequency domain, sampling, signal theory, supersampling | 4 Comments

Tech and scientific writing – graphics, diagram and graph creation tools

Posted on October 22, 2017

Few days ago, I asked a question on twitter: https://twitter.com/BartWronsk/status/919618905319997440 “What is industry/academic standard for diagrams in tech writing? PowerPoint/GoogleDocs diagrams? Dedicated tool like Visio/Dia? Procedural? I usually use first, but far from satisfied…For proc tried SVG,JS,Graphviz,even Mathematica, but results … Continue reading →

Posted in Code / Graphics | Tagged diagrams, mathematica, mathematics, tech writing, tools | 3 Comments

Separable disk-like depth of field

Posted on August 6, 2017

This is a short note accompanying shadertoy: https://www.shadertoy.com/view/lsBBWy . It is direct implementation of “Circularly symmetric convolution and lens blur” by Olli Niemitalo (no innovation on my side, just a toy implementation) and got inspired by Kleber Garcia’s Siggraph 2017 presentation “Circular … Continue reading →

Posted in Code / Graphics | Tagged bokeh, depth of field, dof, far cry 4, Gaussian, maths, photography, poisson, postprocessing, separable, witcher 2 | 2 Comments