# Research

## 1-bit news

OK, it’s been a while again, but here are the reasons for being silent. 1-bit LBD reconstruction is out! Remember all those posts about LBDs, FREAKs, BRIEFs, and reconstructing images ? The latest version of tis work is out with a major feature: 1-bit quantized LBDs reconstruction. Yes, 1-bit ! To achieve this, we leverage some results from 1-bit Compressed Sensing thanks to my co-author Laurent Jacques. So, the pre-print is on arxiv and on infoscience, and you can get the code from github.

## The SNR strikes back

The SNR situation is getting worse, or at the very least more and more intriguing.

## Linearized model of LBPs

LBP model An LBP can be decomposed into two tiers: first, a real description vector, obtained by convolution-then-difference then the quantization (binarization) operation. Mathematically, the real i-th component of the descriptor is computed with the formula: $${\mathcal L}(p)i = \langle{\mathcal G}{x_i, \sigmai} , p \rangle - \langle G{x_i’, \sigmai’} , p\rangle,$$ where ${\mathcal G}{x_i, \sigmai}, {\mathcal G}{x’_i, \sigma’_i}$ are two Gaussians. The variety of the LBP family comes from the choice of these Gaussians : they can have a fixed size but random positions (a la BRIEF), fixed sizes and positions (a la BRISK)1… The choice in FREAK was :

## SNR, why have you forsaken me ?

I’m not as much on FREAKs reconstruction and blogging as I wished, because I have one really important target for the next 6 months: submitting my thesis before the end of the year. The dreaded SNR measure We’ve come up with a nice equation in the past few months (hence, this work is completely unpublished) and after managing to implement it I’m now testing it to show that it is actually outstanding.

## FREAK reconstruction as an inverse problem

In a previous post, I have briefly introduced our FREAK descriptor, which belongs to the more general family of the LBPs. In this post, I will state mathematically the problem of the reconstruction of an image patch given its descriptor, i.e. answering the question:

Can you guess which image part created this particular description vector ?

## FREAK makes it into OpenCV trunk

Integrating our lab’s FREAK in your vision workflow is getting easier and easier!

## Introducing FREAKs

OK, starting to mix posts in English and French since the English version of the blog is still buggy.

## Teasing

Tweet battle Petite taquinade sur Twitter aujourd’hui avec Igor Carron, le rédacteur du blog Nuit Blanche. Igor1 vantait les mérites d’un article intéressant à partir d’un des résultats présentés : une reconstruction d’image à partir d’une image ayant perdu (aléatoirement) 90% de ses pixels. Mais.. attendez… ne serait-ce pas là un problème d’inpainting ? Si fait ! C’était donc l’occasion rêvée pour reparler du code de ce blog récemment arrivé sur Github.

## Concours : reconnaissance d'actions culinaires

Qui disait que le Pattern Recognition c’était pas du cooking ?

## Définition mathématique de l'inpainting

Les choses compliquées sérieuses commencent.