Speeding-up homography estimation in mobile devices

A critical problem faced by computer vision on mobile devices is reducing the computational cost of algorithms and avoiding visual stalls. In this paper, we introduce a procedure for reducing the number of samples required for fitting a homography to a set of noisy correspondences using a random sampling method. This is achieved by means of a geometric constraint that detects invalid minimal sets. In the experiments conducted, we show that this constraint not only reduces the number of random samples at a negligible computational cost but also balances the processor workload over time preventing visual stalls. In extreme situations of very large outlier proportion and noise level, it reduces in about one order of magnitude the number of required random samples.     

Lipolysis,lipid peroxidation and texture of Serrano ham processed under different ripening temperature conditions

Lipolysis, lipid peroxidation, texture and rancid taste were investigated in Serrano hams processed under low, medium and high ripening temperature conditions (RTC) for 15 months. Medium RTC hams showed the highest contents of saturated and monounsaturated free fatty acids (FFAs) from month 5 to 15 and of polyunsaturated FFAs from month 7 to 12. The primary peroxidation index decreased during ripening in all hams, with higher levels for low RTC hams from month 5 onwards. Contrarily, the secondary peroxidation index increased during ripening in all hams, with higher levels for medium RTC hams from month 7 onwards. Texture parameters varied significantly among ham muscles. Shear force increased during ripening in all hams, with higher values for medium RTC hams, whereas cutting force was not influenced by RTC or ripening time. Rancid taste scarcely developed during ripening and was not affected by RTC.     

Modelling HIV-1 2-LTR dynamics following raltegravir intensification

A model of reservoir activation and viral replication is introduced accounting for the production of 2-LTR HIV-1 DNA circles following antiviral intensification with the HIV integrase inhibitor raltegravir, considering contributions of de novo infection events and exogenous sources of infected cells, including quiescent infected cell activation. The model shows that a monotonic increase in measured 2-LTR concentration post intensification is consistent with limited de novo infection primarily maintained by sources of infected cells unaffected by raltegravir, such as quiescent cell activation, while a transient increase in measured 2-LTR concentration is consistent with significant levels of efficient (R₀ > 1) de novo infection. The model is validated against patient data from the INTEGRAL study and is shown to have a statistically significant fit relative to the null hypothesis of random measurement variation about a mean. We obtain estimates and confidence intervals for the model parameters, including 2-LTR half-life. Seven of the 13 patients with detectable 2-LTR concentrations from the INTEGRAL study have measured 2-LTR dynamics consistent with significant levels of efficient replication of the virus prior to treatment intensification.     

Effect of vacuum ageing on quality changes of lamb steaks from early fattening lambs during aerobic display

The effects of vacuum ageing on the quality changes of lamb steaks during retail display were assessed. Biceps femoris and Quadriceps femoris muscles from thirty early fattening lambs fed barley straw and concentrate or alfalfa and concentrate were used. Half of the muscles were vacuum aged for three weeks (VA), and the other half were not aged (control). Control and VA muscles were sliced and aerobically displayed. Weight loss, pH, aldehyde contents, instrumental color characteristics and color acceptance were measured at display days 1, 3, 7 and 14. At day 1 redness was higher in VA lamb. However, redness of VA lamb decreases more rapidly during further storage. Redness and color acceptance decreased in VA lamb from day 3, whereas in not-aged lamb the decrease was observed from day 7 onwards. From days 7 to 14 a drop of color acceptance accompanied by an increase in pH and a decrease in lightness was observed in control and VA lamb.     

A Non-Invasive Technique for Online Defect Detection on Steel Strip Surfaces

During the production of steel strips, a large amount of surface defects can be generated, due to harsh environmental conditions. A high number of surface defects can lead to rejection by the customer, which represents significant economic losses to the production plant. Thus, it is very important to detect the presence and type of the defects generated during the production of each steel strip. Using this information, it is possible to determine whether a strip is suitable for sale, and it may also be useful to determine the origin of defects and, if possible, prevent them from being generated in subsequent strips. To perform these tasks, non-invasive inspection techniques are usually used, carried out automatically by artificial vision systems. Although the inspection conducted by humans is more accurate, they become fatigued quickly, or may even be unable to carry out the inspection correctly when the forward speed of the strip is high. In this paper, a new detection technique is proposed, based on the division of an image into a set of overlapping areas. The optimum values for the configuration parameters of the detection technique are automatically determined using a genetic algorithm. After the detection phase, all the defects are classified using a neural network. A very satisfactory success rate has been achieved in both detection and classification phases.