2 October 2021

WebP is so great… except it’s not

2021-10-03T05:39:15-04:002 October 2021|Categories: Image processing|1 Comment

I’m a responsible web designer, and as such, since WordPress (finally) accepts media uploads of image/webp MIME type and since all web browsers newer than september 2020 (even Apple Safari \o/) can display it, I have been moving my photos library to WebP. After all, when you create content, the least you can do is to also provide the smoothest user experience around it.

WebP falls [...]

18 April 2021

The sRGB book of color

2021-04-19T15:53:22-04:0018 April 2021|Categories: Image processing|2 Comments

This page is inspired by the Munsell book of color. It aims at showing the sRGB gamut volume (all the visible colors that can be encoded as sRGB triplets), projected into a perceptually uniform lightness/chroma space (using JzAzBz color space[^1]), and sliced across hue planes. The sRGB space is the lowest common denominator of all general-audience screens, and is deemed fit to choose colors for [...]

21 March 2021

Rotation-invariant Laplacian for 2D grids

2022-01-05T17:43:48-05:0021 March 2021|Categories: Calculation|4 Comments

NOTE : this article is a work in progress and not finished yet.


The Laplacian operator $\Delta u$ is the divergence of the gradient, that is the sum of the second-order partial derivatives $\nabla^2 u$ of a multivariate function, which represents the local curvature of this function. This operator is widely used for edge-detection[^1], as well as in partial-differential equations (Poisson, etc.), and other [...]

26 February 2021

Image processing does not kill people… and it’s a shame

2021-03-07T01:07:51-05:0026 February 2021|Categories: Image processing|4 Comments

Among the technical fields, quite a few have the potential to harm the public : the first that come to mind are medicine and civil engineering. Both have in common their scientific basis : studies, data, models and history form a corpus of knowledge and tools used by the practitioners to help making choices. However scientific their basis is, the practice remains an art [...]

9 April 2020

The designer and the drilling machine

2020-04-09T23:15:47-04:009 April 2020|Categories: Mechanical design, Software design|0 Comments

There is a parabola I came up with a few years ago, about design and engineering, and it seems to fulfil its purpose quite well, so I though I might share it here.


p>As a designer, your job is to match someone’s needs/problems with a solution. The tricky part is, that someone is not necessarily the client you talk with and who pays you. As an [...]

16 March 2020

Bilinear interpolation on images stored as Python Numpy ndarray

2020-04-01T11:10:54-04:0016 March 2020|Categories: Image processing|Tags: , |0 Comments


p>If you are working in image processing and using Python as a prototyping script language to test algorithms, you might have noticed that all the libs providing fast image interpolation methods (to either sub-sample or over-sample) work in 8 bits unsigned integers (uint8). This is quite annoying if you are working with floating point images. PIL supports floating point interpolation, but only for one [...]

17 January 2019

Derivating HDR-IPT direct and inverse transformations

2021-03-06T14:45:06-05:0017 January 2019|Categories: Image processing|3 Comments


p>Following my work on the filmic tonemapping, several users have reported issues with very saturated blue areas (stage spotlights, bright skies) and red areas. The grail of image processing is being able to affect colors and brightness independantly. The big conundrum of tonemapping is raising luminance without affecting perceptual colors, and, by color, we mean hue and [...]

30 November 2018

Filmic, darktable and the quest of the HDR tone mapping

2021-03-11T22:25:14-05:0030 November 2018|Categories: Image processing|14 Comments



p>darktable is an open-source software for raw photographs management and processing developped since 2009 for Linux desktops. Since then, it has been ported on Mac OS and Windows 7, 8, 10. After having used it for 7 years, I begun to develop in it 3 months ago. This article shows my work and results to improve the HDR-scenes [...]

28 September 2018

Web design and no-coding CMS : are we going the right way ?

2021-03-24T20:48:37-04:0028 September 2018|Categories: Software design|0 Comments

I have been using WordPress as a CMS (content management system) for almost 10 years now. When I dug into it, I knew nothing about PHP, SQL, CSS, programmation and servers. That was one year after I switched from Windows Vista to Linux Ubuntu. I remember the big selling point of WordPress was its “15 min installation with no coding knowledge”. Slowly, I began hacking [...]

5 May 2018

Make Jupyter Notebooks easy to blog in WordPress

2021-03-24T20:48:50-04:005 May 2018|Categories: Calculation|Tags: , , , , |5 Comments

I have struggled with most solutions to convert and embed Jupyter notebooks into WordPress blog posts since I use Plotly as a graphic lib, as well as many LaTeX equations and images. Finally, I had to code my way through. Here is what I did :

1. Write the jupyter notebook

Nothing that you don’t know here. If you embed pictures in the notebook though, it would [...]

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