# Tag Archives: graphics

## Gradient-descent optimized recursive filters for deconvolution / deblurring

This post is a follow-up 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

## 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 | | 3 Comments

## Transforming “noise” and random variables through non-linearities

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

## 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 | | 3 Comments

## Exposure Fusion – local tonemapping for real-time 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

## 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 | | 7 Comments

## Neural material (de)compression – data-driven 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 k-SVD 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 | | 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 | | 17 Comments

## Separate your filters! Separability, SVD and low-rank 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 | | 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 | | 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 | | 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 | | 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 | | 10 Comments

## Dithering part three – real world 2D quantization dithering

In previous two parts of this blog post mini-series I described basic uses mentioned blue noise definition, referenced/presented 2 techniques of generating blue noise and one of many general purpose high-frequency low-discrepancy sampling sequences. In this post, we will look … Continue reading

Posted in Code / Graphics | | 7 Comments

## Dithering part two – golden ratio sequence, blue noise and highpass-and-remap

In previous part of the mini-series 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 | | 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 | | 9 Comments

## Image dynamic range

Intro This post is a second part of my mini-series 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 | | 13 Comments