3D Volumetric Reconstruction and Characterization of Objects from Uncalibrated Images

Three-dimensional (3D) object reconstruction using only bi-dimensional (2D) images has been a major research topic in Computer Vision. However, it is still a complex problem to solve, when automation, speed and precision are required. In the work presented in this paper, we developed a computational platform with the main purpose of building 3D geometric models from uncalibrated images of objects. Simplicity and automation were our major guidelines to choose volumetric reconstruction methods, such as Generalized Voxel Coloring. This method uses photo-consistency measures to build an accurate 3D geometric model, without imposing any kind of restrictions on the relative motion between the camera used and the object to be reconstructed. Our final goal is to use our computational platform in building and characterize human external anatomical shapes using a single off-the-shelf camera

BIOMECHANICS OF THE PENALTY STROKE IN ROLLER HOCKEY

This paper describes a preliminary study on the biomechanics of the shot in roller hockey. This is a Portuguese sport having a most extensive prize list, where Portugal has been 15 times world champion, 20 European champions in senior male competition and won three world championships in senior female. Despite this impressive collection of titles, hockey continues to be the lesser studied sport, concretely regarding studies on biomechanics. The influence of sports equipment in the athlete’s performance and a detailed analysis of the main technical gestures had not motivated yet the researchers for detailed studies to enable their optimization. The purpose of this study was to characterize the mechanical properties of the stick (Aleu) and its influence on the shot power

Infecção urinária em recém-nascido de termo: análise de fatores de risco

OBJETIVOS: Analisar a contribuição dos fatores de risco para a ocorrência de infecção urinária em recém-nascidos de termo. CASUÍSTICA E METODOLOGIA: Estudo retrospectivo (1997), incluindo recém-nascidos de termo com urocultura positiva por saco coletor. A indicação desta coleta foi baseada em: hipertermia (T>;37,8ºC), perda de peso>;10% do peso de nascimento, alterações do estado geral (recusa alimentar, ganho insuficiente de peso e hipoatividade) ou presença de malformações nefro-urológicas. Nesses recém-nascidos foi realizada punção suprapúbica para confirmação diagnóstica. Os recém-nascidos foram divididos em dois grupos, segundo o resultado das uroculturas: Grupo I (diagnóstico presuntivo de infecção urinária) e Grupo II (diagnóstico confirmado de infecção urinária), para avaliação dos fatores de risco pela análise do risco relativo. RESULTADOS: Foram estudadas 61 crianças (5,1% dos recém-nascidos de termo) - Grupo I n=42 (68,9%) e Grupo II n=19 (31,1%). Os fatores de risco avaliados (patologias infecciosas associadas, uso prévio de antibióticos, malformações nefro-urológicas, ventilação mecânica, nutrição parenteral e o uso de cateteres) foram mais freqüentes no Grupo II (pOBJECTIVE: To analyze the correlation of risk factors to the occurrence of urinary tract infection in full-term newborn infants. PATIENTS AND METHODS: Retrospective study (1997) including full-term infants having a positive urine culture by bag specimen. Urine collection was based on: fever, weight loss >; 10% of birth weight, nonspecific symptoms (feeding intolerance, failure to thrive, hypoactivity, debilitate suction, irritability), or renal and urinary tract malformations. In these cases, another urine culture by suprapubic bladder aspiration was collected to confirm the diagnosis. To compare and validate the risk factors in each group, the selected cases were divided into two groups: Group I - positive urine culture by bag specimen collection and negative urine culture by suprapubic aspiration, and Group II - positive urine culture by bag specimen collection and positive urine culture by suprapubic aspiration . RESULTS: Sixty one infants were studied, Group I, n = 42 (68.9%) and Group II, n = 19 (31.1%). The selected risk factors (associated infectious diseases, use of broad-spectrum antibiotics, renal and urinary tract malformations, mechanical ventilation, parenteral nutrition and intravascular catheter) were more frequent in Group II (

Desenvolvimento de uma Plataforma Computacional para Obtenção da Forma 3D de Objectos usando Técnicas de Visão Activa

Neste artigo pretende-se descrever uma plataforma computacional que está a ser desenvolvida para obter a forma 3D de objectos usando técnicas de Visão Activa. Assim, partindo-se de uma sequência de imagens não calibradas do objecto a reconstruir, usando a referida plataforma, pretende-se obter a geometria 3D do objecto em causa

Infecção urinária em recém-nascido de termo: valor da cultura de urina obtida através de saco coletor

OBJETIVE: to evaluate the efficacy of urine culture by bag specimen for the detection of neonatal urinary tract infection in full-term newborn infants. Retrospective study (1997) including full-term newborn infants having a positive urine culture (>100,000 CFU/ml) by bag specimen collection. The urinary tract infection diagnosis was confirmed by positive urine culture (suprapubic bladder aspiration method). The select cases were divided into three groups, according to newborn infant age at the bag specimen collection: GI (< 48 h, n = 17), GII (48 h to 7 d, n = 35) and GIII (> 7 d, n = 9). Sixty one full-term newborn infants were studied (5.1 % of total infants). The diagnosis was confirmed on 19/61 (31.1 %) of full-term infants born alive. Distribution among the groups was: GI = 2/17 (11.8 %), GII = 10//35 (28.6 %), and GIII = 7/9 (77.7 %). The most relevant clinical symptoms were: fever (GI - 100 %, GII - 91.4 %) and weight loss (GI - 35.3 %, GII - 45.7 %). Urine culture results for specimens collected by suprapubic aspiration were: E. coli GI (100 %), GII (40 %) and GIII (28.6 %), E. faecalis GI (30%), Staphylococcus coagulase-negative GII (20 %) and GIII (42.8 %), and Staphylococcus aureus GII (10 %). Correlation between positive urine culture collection (bag specimen method) and urinary tract infection diagnosis, using relative risk analysis, produced the following results: GI=0.30 (CI95% 0.08-1.15), GII=0.51 (CI 95% 0.25-1.06) and GIII=3.31 (CI95% 1.8-6.06) The most frequent urinary tract infection clinical signs in the first week were fever and weight loss, while non-specific symptomatology occurred later. E. coli was most frequent infectious agent, although from the 7th day of life, staphylococcus was noted. The urine culture (bag specimen method) was effective in detecting urinary tract infection only after the 7th day of life.OBJETIVO: avaliar a eficácia da cultura de urina obtida através de saco coletor na detecção de infecção do trato urinário no período neonatal. Estudo retrospectivo (1997), englobando recém-nascidos de termo com urocultura positiva (>100000UFC/ml) colhida em saco coletor. Nesses recém-nascidos foi realizada punção suprapúbica, coletando-se urina para cultura, para confirmação diagnóstica. Os recém-nascidos foram divididos em três grupos, de acordo com a idade do recém-nascido na ocasião da coleta: GI-n=17 (< 48h de vida), GII-n=35 (entre 48h e 7dias) e GIII-n=9 (> 7dias). Foram estudadas 61 crianças (5,1% dos recém-nascidos de termo). A confirmação diagnóstica pela punção suprapúbica mostrou: GI=2/17 (11,8%), GII=10/35 (28,6%) e GIII=7/9 (77,7%). Quanto ao quadro clínico, nos GI e II a febre (100 e 91,4%) e a perda de peso (35,3 e 45,7%) foram os sinais clínicos mais freqüentes. No GIII as alterações do estado geral (66,6%) e a febre (44,4%) destacaram-se. Dentre os agentes etiológicos, obteve-se: E coli GI (100%), GII (40%) e GIII (28,6%), E faecalis GI (30%), S coagulase-negativa GII (20%) e GIII (42,8%) e S aureus GII (10%) e GIII(14,3%). A análise do risco relativo da positividade da cultura de urina obtida por saco coletor corresponder à infecção urinária foi de: GI=0,3 (IC95% 0,08-1,15), GII=0,51 (IC95% 0,25-1,06) e GIII=3,31 (IC95% 1,8-6,06). Os resultados sugerem que os sinais clínicos mais importantes da infecção do trato urinário na primeira semana de vida foram a febre e a perda de peso, enquanto as alterações do estado geral ocorreram mais tardiamente; a E coli foi o agente mais freqüente e, a partir do sétimo dia, houve o aparecimento de S aureus e S coagulase negativa. A cultura de urina através de saco coletor teve maior capacidade de detecção de infecção urinária a partir do setimo dia

Methodological considerations in assessing interlimb coordination on poststroke gait: a scoping review of biomechanical approaches and outcomes

To identify and summarize biomechanical assessment approaches in interlimb coordination on poststroke gait. Interlimb coordination involves complex neurophysiological mechanisms that can be expressed through the biomechanical output. The deepening of this concept would have a significant contribution in gait rehabilitation in patients with an asymmetric neurological impairment as poststroke adults. Poststroke adults (>19 years old), with assessment of interlimb coordination during gait, in an open context, according to the Population, Concept, Context framework. A literature search was performed in PubMed, Web of Science™, Scopus, and gray literature in Google Scholar™, according to the PRISMA-ScR recommendations. Studies written in Portuguese or English language and published between database inception and 14 November 2021 were included. Qualitative studies, conference proceedings, letters, and editorials were excluded. The main conceptual categories were “author/year”, “study design”, “participant’s characteristics”, “walking conditions”, “instruments” and “outcomes”. The search identified 827 potentially relevant studies, with a remaining seven fulfilling the established criteria. Interlimb coordination was assessed during walking in treadmill (n = 3), overground (n = 3) and both (n = 1). The instruments used monitored electromyography (n = 2), kinetics (n = 2), and kinematics (n = 4) to assess spatiotemporal parameters (n = 4), joint kinematics (n = 2), anteroposterior ground reaction forces (n = 2), and electromyography root mean square (n = 2) outcomes. These outcomes were mostly used to analyze symmetry indices or ratios, to calculate propulsive impulse and external mechanical power produced on the CoM, as well as antagonist coactivation. Assessment of interlimb coordination during gait is important for consideration of natural auto-selected overground walking, using kinematic, kinetic, and EMG instruments. These allow for the collection of the main biomechanical outcomes that could contribute to improve better knowledge of interlimb coordination assessment in poststroke patients.info:eu-repo/semantics/publishedVersio

3D Reconstruction of external anatomical structures from image sequences

Three-dimensional (3D) reconstruction of objects from images has been one of the major topics in Computer Vision. Recently, volumetric methods have been successfully used in 3D reconstruction of objects with complex shapes. Comparing with stereo-based methods, they are more efficient in building 3D models of smooth objects [1]. They work in the object volumetric space and do not require a matching process between the images used, which is usually very complex with smooth objects. Volumetric methods represent the object with a finite set of geometric primitives, usually designated by voxels [1, 2].The objective of the work here described is to build a 3D model of the object, with good precision and photorealistic appearance. For that, an image sequence around the object is acquired by an off-the-shelf CCD camera, without imposing any restriction on the motion involved. Then the camera is calibrated by using Zhangs method [3], the object is segmented in all input images and finally its 3D model is built. The employed volumetric approach uses octrees to represent the volume of the object, which is interactively refined in order to achieve the final shape of the object.Two objects were experimentally used to test the approach adopted, a parallelepiped and a human hand model, and the results obtained were quite satisfactory.The future work will be concerned with the implementation of an auto-calibration method and in the 3D reconstruction of deformable objects

3D object reconstruction from uncalibrated images using an off-the-shelf camera

Three-dimensional (3D) objects reconstruction using just bi-dimensional (2D) images has been a major research topic in Computer Vision. However, it is still a hard problem to address, when automation, speed and precision are required and/or the objects have complex shapes or image properties. In this paper, we compare two Active Computer Vision methods frequently used for the 3D reconstruction of objects from image sequences, acquired with a single off-the-shelf CCD camera: Structure From Motion (SFM) and Generalized Voxel Coloring (GVC). SFM recovers the 3D shape of an object based on the relative motion involved, while VC is a volumetric method that uses photo-consistency measures to build the required 3D model. Both methods considered do not impose any kind of restrictions on the relative motion involved