USE OF DECISION TREES IN COLOUR FEATURE SELECTION. APPLICATION TO OBJECT RECOGNITION IN OUTDOOR SCENES

ABSTRACT A new method for the automated selection of colour features is described. The algorithm consists of two stages of processing. In the first, a complete set of colour features is calculated for every object of interest in an image. In the second stage, each object is mapped into several ndimensional feature spaces in order to select the feature set with the smallest variables able to discriminate the remaining objects. The evaluation of the discriminate power for each concrete subset of features is performed by means of decision trees composed of linear discriminate functions. This method can provide valuable help in outdoor scene analysis where no colour space has been demonstrated as being the most suitable. Experiment results recognizing objects in outdoor scenes are reported

How to Join a Wave: Decision-Making Processes in Shimmering Behavior of Giant Honeybees (Apis dorsata)

Shimmering is a collective defence behaviour in Giant honeybees (Apis dorsata) whereby individual bees flip their abdomen upwards, producing Mexican wave-like patterns on the nest surface. Bucket bridging has been used to explain the spread of information in a chain of members including three testable concepts: first, linearity assumes that individual “agent bees” that participate in the wave will be affected preferentially from the side of wave origin. The directed-trigger hypothesis addresses the coincidence of the individual property of trigger direction with the collective property of wave direction. Second, continuity describes the transfer of information without being stopped, delayed or re-routed. The active-neighbours hypothesis assumes coincidence between the direction of the majority of shimmering-active neighbours and the trigger direction of the agents. Third, the graduality hypothesis refers to the interaction between an agent and her active neighbours, assuming a proportional relationship in the strength of abdomen flipping of the agent and her previously active neighbours. Shimmering waves provoked by dummy wasps were recorded with high-resolution video cameras. Individual bees were identified by 3D-image analysis, and their strength of abdominal flipping was assessed by pixel-based luminance changes in sequential frames. For each agent, the directedness of wave propagation was based on wave direction, trigger direction, and the direction of the majority of shimmering-active neighbours. The data supported the bucket bridging hypothesis, but only for a small proportion of agents: linearity was confirmed for 2.5%, continuity for 11.3% and graduality for 0.4% of surface bees (but in 2.6% of those agents with high wave-strength levels). The complimentary part of 90% of surface bees did not conform to bucket bridging. This fuzziness is discussed in terms of self-organisation and evolutionary adaptedness in Giant honeybee colonies to respond to rapidly changing threats such as predatory wasps scanning in front of the nest

Abstract Segmentation and description of natural outdoor scenes

A scene description and segmentation system capable of recognising natural objects (e.g. sky, trees, grass) under different outdoor conditions is presented. We propose an hybrid and probabilistic classifier of image regions as a first step in solving the problem of scene context generation. We focus our work in the problem of image regions labeling to classify every pixel of a given image into one of several predefined classes. The result is both a segmentation of the image and a recognition of each segment as a given object class or as an unknown segmented object. Classification performance has been evaluated with the Outex dataset and compared to the approach of Martí et al. (IVC 2001) and He et al. (CVPR 2004) using their own datasets, showing the superiority of our method. Ó 2006 Elsevier B.V. All rights reserved

Síndrome de abstinencia en un neonato secundario al empleo de fentanilo transdérmico durante la gestación

Fentanyl is a synthetic opioid one hundred times more potent than morphine. Its pharmacologic profile makes it a suitable drug for transdermal delivery in patients with severe oncological and non-oncological chronic pain. So far, only one case of neonatal opioid withdrawal syndrome following the use of transdermal fentanyl in a pregnant patient has been reported. A 35 year old patient in her 23rd week of pregnancy presenting severe lumbar pain (VAS 10) irradiated to lower limbs, as a consequence of paraplegia following surgery for scoliosis at the age of 16 and re-intervention for stabilisation arthrodesis at the age of 32, developed an acute episode of pain in the 20th week of pregnancy. Therapy with paracetamol, metamizol, ketorolac, pethidine and morphine chloride was ineffective, and pain was eventually controlled with fentanyl 50 mcg/h plus oral morphine sulphate 5-10 mg for breakthrough pain; this therapy was maintained for the remaining of the pregnancy. Early delivery took place at the 34th week and the newborn showed a syndrome suggestive of withdrawal in the first 24 hours of life. The baby was admitted to the neonatal intensive care unit, remaining intubated for six days and requiring decreasing doses of morphine chloride until discharge in the 18th day. Psychomotor development during her first six months of life was normal. Her mother´s opioid requirements were progressively reduced and were eventually interrupted, without any pain relapse. Neonatal opioid withdrawal syndrome can occur following prolonged administration of opioids in pregnant women. Its symptoms in the first 24-48 hours of life are neurological (tremor, irritability, hypertonicity, convulsions, discoordination), autonomous (fever, sweating) digestive (diarrhea, vomiting) respiratory (hypoventilation, taquipnea) poor weight gain and dehydration. Opioids, neuroleptics, benzodiazepines, barbiturates and alfa-2 agonists can be used for its treatment. The syndrome has been reported in the new-borns of pregnant women consuming heroin or methadone, but not after prolonged treatments with fentanyl. An unknown effect of this frequent therapy for chronic severe pain is reported. Although further research is required, fentanyl can be regarded as a last choice treatment for severe pain in pregnant women when first and second WHO analgesic ladder drugs are not effective.El fentanilo es un opioide sintético 100 veces más potente que la morfina. Sus características farmacológicas lo hacen un buen fármaco para la administración transdérmica en pacientes con dolor crónico severo de origen oncológico y no oncológico. Hasta el nuestro sólo ha sido publicado un caso referente al empleo de fentanilo transdérmico (FT) en mujeres gestantes y el consiguiente síndrome de abstinencia neonatal a opiáceos (SANO). Mujer de 35 años, gestante de 23 semanas, controlada domiciliariamente por presentar dolor severo (EVA 10) en región lumbar irradiado a miembros inferiores, secundario a paraplejia tras intervención por escoliosis a los 16 años y a reintervención con artrodesis estabilizadora a los 32, y reagudizado desde la 20ª semana de gestación. Tras tratamiento inefectivo con paracetamol, metamizol, ketorolaco, petidina y cloruro mórfico, se controló el cuadro con FT a dosis de 50 mg/h y sulfato de morfina oral a dosis de 5-10 mg a demanda como rescate, que se mantuvieron durante el resto de la gestación. El parto se produjo prematuramente a las 34 semanas, y la recién nacida mostró clínica compatible con SANO en las primeras 24 horas. Fue ingresada en la UCI neonatal con intubación hasta el sexto día, siendo tratada con dosis decrecientes de cloruro mórfico hasta la suspensión previa al alta al 18º día de vida. Durante sus primeros seis meses de vida la niña ha presentado un adecuado desarrollo psicomotor. En su madre se ha reducido progresivamente la dosis de opiáceos hasta suspenderlos, sin reaparición de la clínica de dolor. El SANO aparece en recién nacidos cuyas madres han recibido opioides de forma prolongada durante la gestación. Se presenta en las primeras 24-48 horas de vida con clínica neurológica (temblor, irritabilidad, hipertonicidad, convulsiones, descoordinación), autónoma (fiebre, sudoración), digestiva (diarrea, vómitos) y respiratoria (hipoventilación, taquipnea), con pobre ganancia de peso y deshidratación. En su tratamiento se pueden emplear opioides, neurolépticos, benzodiacepinas, barbitúricos o a2-agonistas. Se ha descrito sobre todo en hijos de madres consumidoras de heroína o metadona durante el embarazo, pero no tras tratamiento prolongado con fentanilo. Con este caso señalamos un efecto poco descrito de un fármaco cada vez más empleado en el tratamiento del dolor crónico severo. Aunque deberían realizarse más estudios, consideramos que el FT podría ser utilizado como tratamiento de última línea en casos de dolor crónico severo en mujeres gestantes cuando no han sido eficaces los fármacos de los dos escalones inferiores de la escalera analgésica de la OMS

Simultaneous surface texture classification and illumination tilt angle prediction

In this paper we investigate the effect of the illuminant tilt rotation over surface textures by analysing a set of image texture features extracted from the co-occurrence matrix. From the behaviour of each texture feature, a simple method able to predict the illuminant tilt angle of test images is developed. Moreover, the method is also used to perform a texture classification invariant to the illuminant tilt angle rotation. This study and experimental results over different real textures show that the illumination tilt angle can be accurately predicted, as part of the texture classification process.