
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: graphics
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
Transforming “noise” and random variables through nonlinearities
This post covers a topic slightly different from my usual ones and something I haven’t written much about before – applied elements of probability theory. We will discuss what happens with “noise” – a random variable – when we apply … Continue reading
Posted in Code / Graphics
Tagged blue noise, graphics, graphics programming, image processing, jax, mathematics, maths, noise, programming, python
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Fast, GPU friendly, antialiasing downsampling filter
In this shorter post, I will describe a 2X downsampling filter that I propose as a “safe default” for GPU image processing. It’s been an omission on my side that I have not proposed any specific filter despite writing so … Continue reading
Posted in Code / Graphics
Tagged filtering, graphics, graphics programming, image processing, jax, postprocessing, signal processing
3 Comments
Exposure Fusion – local tonemapping for realtime rendering
In this post I want to close the loop and come back to the topic I described ~6y ago! Local tonemapping (I’ll refer to it as LTM) – a component I considered a missing piece in video games rendering, especially … Continue reading
Posted in Code / Graphics
Tagged bilateral, graphics, graphics programming, image processing, postprocessing, tonemapping
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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
Neural material (de)compression – datadriven nonlinear dimensionality reduction
In this post I come back to something I didn’t expect coming back to – dimensionality reduction and compression for whole material texture sets (as opposed to single textures) – a significantly underexplored topic. In one of my past posts … Continue reading
Why are video games graphics (still) a challenge? Productionizing rendering algorithms
Intro This post will cover challenges and aspects of production to consider when creating new rendering / graphics techniques and algorithms – especially in the context of applied research for real time rendering. I will base this on my personal … Continue reading
Compressing PBR material texture sets with sparsity and kSVD dictionary learning
Introduction In this blog post, I am going to continue exploration of compressing whole PBR texture sets together (as opposed to compressing each texture from the set separately) and using the fact that those textures are strongly correlated. In my … Continue reading
Posted in Code / Graphics
Tagged compression, graphics, graphics programming, image processing, linear algebra, machine learning, maths, PBR, rendering, signal processing, textures
8 Comments
Dimensionality reduction for image and texture set compression
In this blog post I am going to describe some of my past investigations on reducing the number of channels in textures / texture sets automatically and generally – without assuming anything about texture contents other than correspondence to some … Continue reading
Posted in Code / Graphics
Tagged compression, graphics, image processing, linear algebra, machine learning, maths, PBR, physicallybased shading, textures
17 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
Local linear models and guided filtering – an alternative to bilateral filter
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
7 Comments
How (not) to test graphics algorithms
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
4 Comments
Cull that cone! Improved cone/spotlight visibility tests for tiled and clustered lighting
In this blog post, I will present some common spotlight culling techniques and propose one small improvement that is able to correct results of cheap, tiled / clustered culling on the CPU/GPU with almost negligible ALU cost. If you know … Continue reading
Posted in Code / Graphics
Tagged cone, culling, geometry, graphics, ideas, lighting, mathematica, mathematics, occlussion, programming, sphere, spot, visibility
9 Comments
Small float formats – R11G11B10F precision
While this post is not yet dithering related, it is in a way a part of my series about dithering. You can check index of all parts here or check the previous part. I will talk here about use of … Continue reading
Posted in Code / Graphics
Tagged float, floating point, floats, graphics, mathematica, mathematics, noise, programming, quantization, rendering
10 Comments
Dithering part three – real world 2D quantization dithering
In previous two parts of this blog post miniseries I described basic uses mentioned blue noise definition, referenced/presented 2 techniques of generating blue noise and one of many general purpose highfrequency lowdiscrepancy sampling sequences. In this post, we will look … Continue reading
Posted in Code / Graphics
Tagged bayer, blue noise, dithering, fourier, graphics, graphics programming, interleaved gradient noise, mathematica, mathematics, maths, noise, programming, sampling
7 Comments
Dithering part two – golden ratio sequence, blue noise and highpassandremap
In previous part of the miniseries I covered dithering definition and how dithering changes error characteristics of simple 1D quantization and functions. In this part I will try to look at what blue noise is, but first wanted to have a … Continue reading
Posted in Code / Graphics
Tagged blue noise, dithering, golden ratio, graphics, graphics programming, low discrepancy, noise, programming
11 Comments
Dithering in games – mini series
This an opening post of mini blog post series about various uses of dithering for quantization and sampling in video games. It is something most of us use intuitively in every day work, so wanted to write down some of … Continue reading
Posted in Code / Graphics
Tagged blue noise, dithering, graphics, graphics programming, mathematica, noise, programming, sampling
9 Comments
Image dynamic range
Intro This post is a second part of my miniseries about dynamic range in games. In this part I would like to talk a bit about dynamic range, contrast/gamma and viewing conditions. You can find the other post in the series here and … Continue reading
Posted in Code / Graphics
Tagged dynamic range, graphics, graphics programming, HDR, mathematica, mathematics, postprocessing, tonemapping, visuals
13 Comments
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