Prise en compte des discontinuités dans un algorithme de super-résolution

Dans la plupart des problèmes de reconstruction utilisant une régularisation classique, les discontinuités sont lourdement pénalisées. C'est notamment le cas pour les modèles de reconstruction d'une image haute résolution à partir d'une séquence d'images basse résolution présentant un décalage sous-pixélique. Notre but est ici de tenir compte des discontinuités dans les images afin de remédier à l'aspect contradictoire de la super-résolution qui vise à retrouver des hautes fréquences tout en régularisant. Nous nous sommes placés dans un cadre probabiliste et les images ont été modélisées par un champ de Markov. Lors de notre étude, nous avons comparé différents 0-modèles a priori eu égard à leur influence sur la préservation des discontinuités

Soy protein–gum karaya conjugate: emulsifying activity and rheological behavior in aqueous system and oil in water emulsion

The main objective of this study is to investigate the effects of mixing and conjugation of soy protein isolate (SPI) with gum karaya on the characteristics of the hybrid polymer (protein–gum) in both aqueous systems and oil-in-water (O/W) emulsions. It was hypothesized that the covalent linkage of gum karaya with SPI would improve the emulsifying activity and rheological properties of both polymers. Conjugation occurred under controlled conditions (i.e., 60 °C and 75 % relative humidity, 3 days). The conjugated hybrid polymer produced smaller droplet with better uniformity, higher viscosity and stronger emulsifying activity than native gum karaya, suggesting the conjugated polymer provided a bulkier secondary layer with more efficient coverage around oil droplets, thereby inducing stronger resistance against droplet aggregation and flocculation. Emulsions containing the native gum karaya produced the largest droplet size among all prepared emulsions (D 3,2 = 8.6 μm; D 4,3 = 22.4 μm); while the emulsion containing protein–gum conjugate (1:1 g/g) had the smallest droplet size (D 3,2 = 0.2 μm; D 4,3 = 0.7 μm) with lower polydispersity. The protein–gum conjugate (1:1 g/g) also showed the highest elastic and viscous modulus, the lowest polydispersity (span) and the highest emulsifying activity among all native, mixed and conjugated polymers. Therefore, the percentage of gum karaya used for production of O/W emulsion can be decreased by partially replacing it with the conjugated gum

Subpixel image registration by estimating the polyphase decomposition of cross power spectrum

A method of registering images at subpixel accuracy has been proposed, which does not resort to interpolation. The method is based on the phase correlation method and is remarkably robust to correlated noise and uniform variations of luminance. We have shown that the cross power spectrum of two images, containing subpixel shifts, is a polyphase decomposition of a Dirac delta function. By estimating the sum of polyphase components one can then determine subpixel shifts along each axis.