
Recent Posts
 Gradientdescent optimized recursive filters for deconvolution / deblurring September 5, 2022
 Progressive image stippling and greedy blue noise importance sampling August 31, 2022
 Removing blur from images – deconvolution and using optimized simple filters May 26, 2022
 Transforming “noise” and random variables through nonlinearities March 16, 2022
 Fast, GPU friendly, antialiasing downsampling filter March 7, 2022
Categories
Tag Archives: algorithms
Gradientdescent optimized recursive filters for deconvolution / deblurring
This post is a followup to my post on deconvolution/deblurring of the images. In my previous blog post, I discussed the process of “deconvolution” – undoing a known convolution operation. I have focused on traditional convolution filters – “linear phase, … Continue reading
Posted in Code / Graphics
Tagged algorithms, digital signal processing, graphics, graphics programming, image processing, jax, maths, numpy, python, signal processing
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Progressive image stippling and greedy blue noise importance sampling
Introduction I recently read the “Gaussian Blue Noise” paper by Ahmed et al. and was very impressed by the quality of their results and the rigor of their method. They provide a theoretical framework to analyze the quality of blue … Continue reading
Posted in Code / Graphics
Tagged algorithms, blue noise, dithering, graphics, graphics programming, image processing, jax, programming, python, sampling
3 Comments
Study of smoothing filters – SavitzkyGolay filters
Last week I saw Daniel Holden tweeting about SavitzkyGolay filters and their properties (less smoothing than a Gaussian filter) and I got excited… because I have never heard of them before and it’s an opportunity to learn something. When I … Continue reading
Posted in Code / Graphics
Tagged algorithms, digital signal processing, image processing, maths, python, signal processing
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Practical Gaussian filtering: Binomial filter and small sigma Gaussians
Gaussian filters are the bread and butter of signal and image filtering. They are isotropic and radially symmetric, filter out high frequencies extremely well, and just look pleasant and smooth. In this post I will cover two of my favorite … Continue reading
Processing aware image filtering: compensating for the upsampling
This post summarizes some thoughts and experiments on “filtering aware image filtering” I’ve been doing for a while. The core idea is simple – if you have some “fixed” step at the end of the pipeline that you cannot control … Continue reading
Posted in Code / Graphics
Tagged algorithms, digital signal processing, filtering, graphics, image processing, jax, postprocessing, signal processing
7 Comments
Comparing images in frequency domain. “Spectral loss” – does it make sense?
Recently, numerous academic papers in the machine learning / computer vision / image processing domains (re)introduce and discuss a “frequency loss function” or “spectral loss” – and while for many it makes sense and nicely improves achieved results, some of … Continue reading
Posted in Code / Graphics
Tagged algorithms, image processing, linear algebra, machine learning, maths, neural networks
3 Comments
Separate your filters! Separability, SVD and lowrank approximation of 2D image processing filters
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
15 Comments
Technical debt… or technical weight?
Introduction Whole idea for this post came from a very inspiring conversation with my friends and excolleagues from Ubisoft that we had over a dinner few months ago. We started to talk about some sophisticated code algorithm – an algorithm … Continue reading
Posted in Code / Graphics
Tagged algorithms, architecture, code design, programming, psychology
2 Comments
Fixing screenspace deferred decals
Screenspace deferred decals are a very popular technique. There were so many presentations and blog posts about it that I will just list couple of them (just a first google search results page to be honest…) in no particular order: … Continue reading
Anamorphic lens flares and visual effects
Introduction There are no visual effects that are more controversial than various lens and sensor effects. Lens flares, bloom, dirty lens, chromatic aberrations… All of those have their lovers and haters. Couple years ago many games used cheap pseudo HDR effect … Continue reading
Posted in Code / Graphics
Tagged algorithms, anamorphic, bokeh, C#, cinematography, depth of field, film, flares, graphics, graphics programming, history, lens, movies, photography, postprocessing, programming
16 Comments
Designing a nextgeneration posteffects pipeline
Hey, it’s been a while since my last post. Today I will focus on topic of posteffects. Specifically, I wanted to talk about nextgen post process pipeline and redesign I worked on while being a part of Far Cry 4 rendering team. … Continue reading
Posted in Code / Graphics
Tagged 1080p, algorithms, bokeh, depth of field, far cry 4, graphics, graphics programming, photography, PlayStation 4, postprocessing, programming, tonemapping, Xbox One
6 Comments
Review: “Multithreading for Visual Effects”, CRC Press 2014
Today I wrote a short review about a book I bought and read recently – “Multithreading for Visual Effects” published by CRC Press 2014 and including articles by Martin Watt, Erwin Coumans, George ElKoura, Ronald Henderson, Manuel Kraemer, Jeff Lait, James Reinders. … Continue reading
Python as scientific toolbox – 8 months later
I started this blog with a simple post about my attempts to find free Mathematica replacement tool for general scientific computing with focus on graphics. At that time I recommended scientific Python and WinPython environment. Many months have passed, I … Continue reading
Posted in Code / Graphics
Tagged algorithms, Anaconda, mathematica, python, sublime text, tools, winpython
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Updated Poissonlike generator with GUI and more
Just a super short note: I updated my simple renderingoriented Poissonlike pattern generator with: Very simple GUI made in PyQt to make experimenting easier. Option to do rotating disk (with minimizing rotated point distance) for things like Poisson bokeh / … Continue reading
Posted in Code / Graphics
Tagged algorithms, Anaconda, antialiasing, graphics programming, mathematica, poisson, programming, pyqt, python, stochastic
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Major C#/.NET graphics framework update + volumetric fog code!
As I already promised too many times, here comes major CSharpRenderer framework update! As always, all code available on GitHub. Note that the goal is still the same – not to write most beautiful or fast code, but to provide a … Continue reading
Posted in Code / Graphics
Tagged .NET, algorithms, C#, graphics, graphics programming, postprocessing, supersampling, temporal, temporal supersampling
18 Comments
Poisson disk/square sampling generator for rendering
I have just submitted onto GitHub small new script – Poissonlike distribution sampling generator suited for various typical rendering scenarios. Unlike other small generators available it supports many sampling patterns – disk, disk with a central tap, square, repeating grid. It … Continue reading
Posted in Code / Graphics
Tagged algorithms, Anaconda, programming, python, stochastic, supersampling, temporal, tools, winpython
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Hair rendering trick(s)
I didn’t really plan to write this post as I’m quite busy preparing for Siggraph and enjoying awesome Montreal summer, but after 3 similar discussion with friends developers I realized that the simple hair rendering trick I used during the … Continue reading
C#/.NET graphics framework on GitHub + updates
As I promised I posted my C#/.NET graphics framework (more about it and motivation behind it here) on GitHub: This is my first GitHub submit ever and my first experience with Git, so there is possibility I didn’t do something properly … Continue reading
Posted in Code / Graphics
Tagged .NET, algorithms, antialiasing, C#, graphics, graphics programming
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