Browsing by Author "Aguilera Radic, José Miguel"

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    Automated Detection of Fish Bones in Salmon Fillets Using X-ray Testing
    (IEEE, 2010) Mery Quiroz, Domingo Arturo; Lillo Valles, Iván Alberto; Löbel Díaz, Hans-Albert; Riffo Bouffanais, Vladimir; Soto Arriaza, Álvaro; Cipriano, Aldo; Aguilera Radic, José Miguel
    X-ray testing is playing an increasingly important role in food quality assurance. In the production of fish fillets, however, fish bone detection is performed by human operators using their sense of touch and vision which can lead to misclassification. In countries where fish is often consumed, fish bones are some of the most frequently ingested foreign bodies encountered in foods. Effective detection of fish bones in the quality control process would help avoid this problem. For this reason, we developed an X-ray machine vision approach to automatically detect fish bones in fish fillets. This paper describes our approach and the corresponding validation experiments with salmon fillets. The approach consists of six steps: 1) A digital X-ray image is taken of the fish fillet being tested. 2) The X-ray image is filtered and enhanced to facilitate the detection of fish bones. 3) Potential fish bones in the image are segmented using band pass filtering, thresholding and morphological techniques. 4) Intensity features of the enhanced X-ray image are extracted from small detection windows that are defined in those regions where potential fish bones were segmented. 5) A classifier is used to discriminate between 'bones' and 'no-bones' classes in the detection windows. 6) Finally, fish bones in the X-ray image are isolated using morphological operations applied on the corresponding segments classified as 'bones'. In the experiments we used a high resolution flat panel detector with the capacity to capture up to a 6 million pixel digital X-ray image. In the training phase, we analyzed 20 representative salmon fillets, 7700 detection windows (10×10 pixels) and 279 intensity features. Cross validation yielded a detection performance of 95% using a support vector machine classifier with only 24 selected features. We believe that the proposed approach opens new possibilities in the field of automated visual inspection of salmon and other similar fish.
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    Determination of a Representative Volume Element Based on the Variability of Mechanical Properties with Sample Size in Bread
    (2010) Ramírez, Cristián; Young, Ashley; James, Bryony; Aguilera Radic, José Miguel
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    Rheological and tribological properties of seaweed powders as thickeners for liquid foods
    (2024) Covacevich Flores, Leyla Francisca; Aguilera Radic, José Miguel; Moreno Constenla, María Carolina; Brossard Aravena, Natalia Daniela; Osorio Lira, Fernando Alberto
    Thickened liquid foods are particularly interesting in culinary applications and the management of swallowing disorders. Polysaccharide molecules and suspended soft particles play a major role in increasing viscosity and mouthfeel. In this work, tribo-rheological effects of finely ground particles (less than 75 microns) of Durvillaea antarctica seaweed (SP) as a minimally processed and natural alternative to commercial thickeners were studied. Shear viscosity (η), viscoelastic moduli (G’, G’’), and the coefficient of friction (CoF) were determined for SP dispersions, using as controls two commercial thickeners: modified maize starch-based (TE) and xanthan gum-based (TU). SP and SP dispersions were characterized microstructurally and evaluated at concentrations of 1.2%, 2.4%, and 4.8% w/v, with and without artificial saliva (AS). SP dispersions exhibited a pseudoplastic behavior in the range of shear rates 0.1-100 s-1 and viscoelasticity (G’>G”) in the 0.1-80 rad/s frequency range. The incorporation of AS had a dilution effect in SP and TU dispersions, but additionally, in the case of TE, a hydrolyzing effect decreased the values of the responses. In the tribology experiments, all samples followed a Stribeck curve. SP dispersions were more lubricating than AS and controls in the physiological range of velocities during oral processing and swallowing (e.g.,>100 mm/s). The thickening, viscoelastic, and lubrication behavior of SP dispersions were attributed to the soluble solids released from the SP (37%-51% d.w.) and interactions with ghosts of SP particles in the continuous aqueous phase. Fine seaweed particles may be a sustainable and low-cost alternative to commercial thickeners in some food applications