Enhancing open-set face recognition by closing it with Cluster-Inferred Gallery Augmentation

In open-set face recognition - as opposed to closed-set face recognition - it is possible that the identity of a given query is not present in the gallery set. In that case, the identity of the query can only be correctly classified as "unknown" when the similarity with the gallery faces is below a threshold that was determined a priori. However, in many use-cases, the set of queries contains multiple instances of the same identity, whether or not this identity is represented in the gallery. Thus, the set of query faces lends itself to identity clustering that could yield representative instances for unknown identities. By augmenting the gallery with these instances, we can make an open-set face recognition problem more closed. In this paper, we show that this method of Cluster-Inferred Gallery Augmentation (CIGA) does indeed improve the quality of open-set face recognition. We evaluate the addition of CIGA for both a private dataset of images taken in a school context and the public LFW dataset, showing a significant improvement in both cases. Moreover, an implementation of the suggested approach along with our experiments are made publicly available on https://gitlab.com/florisdf/acpr2019.status: accepte

Automatically Selecting the Best Pictures for an Individualized Child Photo Album

In this paper we investigate the best way to automatically compose a photo album for an individual child from a large collection of photographs taken during a school year. For this, we efficiently combine state-of-the-art identification algorithms to select relevant photos, with an aesthetics estimation algorithm to only keep the best images. For the identification task, we achieved 86% precision for 86% recall on a real-life dataset containing lots of specific challenges of this application. Indeed, playing children appear in non-standard poses and facial expressions, can be dressed up or have their faces painted etc. In a top-1 sense, our system was able to correctly identify 89.2% of the faces in close-up. Apart from facial recognition, we discuss and evaluate extending the identification system with person re-identification. To select out the best-looking photos from the identified child photos to fill the album with, we propose an automatic assessment technique that takes into account the aesthetic photo quality as well as the emotions in the photos. Our experiments show that this measure correlates well with a manually labeled general appreciation score.status: publishe

Deep Diamond Re-ID.

Re-identification neural networks are widely used in numerous applications such as crowd control, crime investi- gations, safety systems and even in most smartphones to unlock the phone with a picture of the owner. These techniques are mostly used to re-identify faces or persons but in this paper we investigate the possibility to adapt these to also re-identify similar looking objects such as diamonds. Since polished diamonds are very similar to the naked eye, it is difficult to distinguish one diamond from another. We have indications that diamonds are sometimes switched by trained switchers with fake or less expensive stones, while they pretend to inspect the stone. A solution to this is diamond fingerprinting. We therefore propose a technique to generate a unique ID for each stone, which allows to re-identify the diamond solely based on an image of the gem. Since each diamond is assigned a unique ID it is even possible to keep track of the diamonds over time. This allows the seller to verify his stones before and after trading while switchers don’t stand a chance. For this task we trained and adapted a classification network optimized for both speed and accuracy.status: submitte

Trapping of Charged Gold Adatoms by Dimethyl Sulfoxide on a Gold Surface

10siWe report the formation of dimethyl sulfoxide (DMSO) molecular complexes on Au(111) enabled by native gold adatoms unusually linking the molecules via a bonding of ionic nature, yielding a mutual stabilization between molecules and adatom(s). DMSO is a widely used polar, aprotic solvent whose interaction with metal surfaces is not fully understood. By combining X-ray photoelectron spectroscopy, low temperature scanning tunneling microscopy, and density functional theory (DFT) calculations, we show that DMSO molecules form complexes made by up to four molecules arranged with adjacent oxygen terminations. DFT calculations reveal that most of the observed structures are accurately reproduced if, and only if, the negatively charged oxygen terminations are linked by one or two positively charged Au adatoms. A similar behavior was previously observed only in nonstoichiometric organic salt layers, fabricated using linkage alkali atoms and strongly electronegative molecules. These findings suggest a motif for anchoring organic adlayers of polar molecules on metal substrates and also provide nanoscale insight into the interaction of DMSO with gold.partially_openembargoed_20160616Feng, Zhijing; Velari, Simone; Cossaro, Albano; Castellarin-Cudia, Carla; Verdini, Alberto; Vesselli, Erik; Dri, Carlo; Peressi, Maria; De Vita, Alessandro; Comelli, GiovanniFeng, Zhijing; Velari, Simone; Cossaro, Albano; Castellarin Cudia, Carla; Verdini, Alberto; Vesselli, Erik; Dri, Carlo; Peressi, Maria; DE VITA, Alessandro; Comelli, Giovann