Tooth decay detection using a fiber optic sensor / Detección de caries dental usando un sensor de fibra óptica

ABSTRACT Introduction: tooth decay has become one of the most prevalent diseases worldwide, but ironically it is one of the most neglected. Currently, adequate and effective caries treatment is based on early diagnosis and procedures such as sealants, crowns, and root canal treatment. Methods: This study examined the behavior of carious and non-carious areas of critical dental units (premolars and molars) subjecting them to a wavelength of 830 nm in adult humans who agreed to a dental exam and had at least one tooth affected by dental caries. Underage persons and patients in medical treatment were excluded. After finding a behavior that helped differentiate decayed tissue from healthy areas, the used experimental system was characterized and tested in volunteers. The implemented system contains a fiber optic sensor comprised of a trifurcated fiber and a photodetector to perform optical power measurements. Results: This sensor detected 100% of dental caries samples on premolar and molar occlusal surfaces. It also showed the ability to diagnose buccal cavities. Conclusions: The results showed that caries can be identified in dental units by means of a fiber optic sensor and infrared light at 830 nm.

RESUMEN. Introducción: la caries se ha manifestado como una de las enfermedades con mayor prevalencia mundial, pero paradójicamente es una de las más desatendidas. En la actualidad, el tratamiento adecuado y eficaz contra la caries se basa en el diagnóstico temprano y en procedimientos como obturaciones, coronas y tratamiento de conductos. Métodos: esta investigación se centró en examinar el comportamiento de zonas cariadas y no cariadas de piezas dentales vitales (premolares y molares) al someterlas a una longitud de onda de 830 nm en seres humanos mayores de edad que aceptasen una revisión odontológica y que presentaran al menos un caso de caries dental. Fueron excluidos menores de edad y personas bajo tratamientos médicos. Tras encontrar un comportamiento que permitió diferenciar entre zonas cariadas y sanas, se caracterizó el sistema experimental usado y se probó en voluntarios. El sistema implementado se basa en un sensor de fibra óptica compuesto por una fibra trifurcada y un fotodetector para realizar mediciones de potencia óptica. Resultados: este sensor detectó el 100% de las muestras de caries dental en superficies oclusales de premolares y molares. Asimismo, exhibió indicios de la capacidad de diagnosticar caries vestibulares. Conclusiones: los resultados mostraron que se puede establecer la presencia de caries en piezas dentales mediante la implementación de un sensor de fibra óptica y luz infrarroja de 830 nm.

Classification of Flying Insects with high performance using improved DTW algorithm based on hidden Markov model

ABSTRACT Insects play significant role in the human life. And insects pollinate major food crops consumed in the world. Insect pests consume and destroy major crops in the world. Hence to have control over the disease and pests, researches are going on in the area of entomology using chemical, biological and mechanical approaches. The data relevant to the flying insects often changes over time, and classification of such data is a central issue. And such time series mining tasks along with classification is critical nowadays. Most time series data mining algorithms use similarity search and hence time taken for similarity search is the bottleneck and it does not produce accurate results and also produces very poor performance. In this paper, a novel classification method that is based on the dynamic time warping (DTW) algorithm is proposed. The dynamic time warping algorithm is deterministic and lacks in modeling stochastic signals. The dynamic time warping (DTW) algorithm is improved by implementing a nonlinear median filtering (NMF). Recognition accuracy of conventional DTW algorithms is less than that of the hidden Markov model (HMM) by same voice activity detection (VAD) and noise-reduction. With running spectrum filtering (RSF) and dynamic range adjustment (DRA). NMF seek the median distance of every reference of time series data and the recognition accuracy is much improved. In this research work, optical sensors are used to record the sound of insect flight, with invariance to interference from ambient sounds. The implementation of our tool includes two parts, an optical sensor to record the "sound" of insect flight, and a software that leverages on the sensor information, to automatically detect and identify flying insects.