The analysis of urine sediments (Urinalysis) is a common procedure in diagnostic laboratories, an... more The analysis of urine sediments (Urinalysis) is a common procedure in diagnostic laboratories, and allows the identification of important diseases. This procedure is usually done by a professional, which performs a visual inspection of microscope slides containing urine, aiming to identify crystals, bacteria and other relevant elements, resulting in a laborious task. The automation of this task is of great value to medicine and related areas, raising the quality and reliability of diagnosis and reducing the time spent with these tasks. This paper describes a new method for automating the analysis of urine sediments in digital images that has the main goal of finding cystine crystals. Real images obtained from a microscope and from some public image databases were used to test the developed algorithm, which demonstrated satisfactory results with 73.72% and 93.08% of sensitivity and specificity, respectively.
This work consists of the study of techniques of robotics and virtual reality to develop a simula... more This work consists of the study of techniques of robotics and virtual reality to develop a simulator that can be used in robotics schools, having an adequate visualization and a simple and intuitive way of interaction. For this, a 3D virtual environment for robotics was developed. Virtual reality resources have been incorporated to improve the visualization and to facilitate the user interaction with the environment. In order to evaluate the effectivity of the environment, user experiments were carried out on four different hardware configurations. During the simulations, the users had to create trajectories while implicitly defining reference points. From these experiments, automatic reports for the quantitative questions were generated, and questionnaires were filled for the qualitative questions. The results have shown that the use of virtual reality do helps the users in task execution, improving the visualization, reducing the time spent for the tasks and increasing the precision.
In radiology, virtual reality has emerged as a candidate to solve some issues of the area, such a... more In radiology, virtual reality has emerged as a candidate to solve some issues of the area, such as the ambient lighting and ergonomic postures when diagnosing. The goal of this study is to explore the literature of virtual reality in radiology in order to define and describe the state-of-the-art in addition to finding gaps and opportunities for future research. To do so, we carried out a systematic mapping study covering the period from January 2014 to July 2021. We initially found 329 papers to be reviewed, but after applying our exclusion criteria we ended up with 24 primary studies. Our results suggest that the use of virtual reality has grown recently in the field, however there are many gaps and opportunities to explore in the area.
Anais Estendidos do XXI Simpósio Brasileiro de Jogos e Entretenimento Digital (SBGames Estendido 2022)
Virtual characters can elicit an uncomfortable sensation usually known as Uncanny Valley (UV). Ev... more Virtual characters can elicit an uncomfortable sensation usually known as Uncanny Valley (UV). Evidence suggests that animation exacerbates the UV effect. This paper revisits the UV hypothesis to assess its effects on people’s perception of virtual characters, to try to answer the questions “What happens to the perceptual comfort if, in addition to images and videos of characters, we include those characters in an interactive Virtual Reality (VR) environment?”, and “Considering the VR environment, do people feel equally comfortable if we increase the number of characters?”. The results indicate that there are differences in the perception of scenarios with low and high densities.
Background: Age-related cognitive decline impacts cognitive abilities essential for driving. Obje... more Background: Age-related cognitive decline impacts cognitive abilities essential for driving. Objective: We aimed to measure main cognitive functions associated with a high number of traffic violations in different driving settings. Methods: Thirty-four elderly individuals, aged between 65 and 90 years, were evaluated with a driving simulator in four different settings (Intersection, Overtaking, Rain, and Malfunction tasks) and underwent a battery of cognitive tests, including memory, attention, visuospatial, and cognitive screening tests. Individuals were divided into two groups: High-risk driving (HR, top 20% of penalty points) and normal-risk driving (NR). Non-parametric group comparison and regression analysis were performed. Results: The HR group showed higher total driving penalty score compared to the NR group (median=29, range= 9-44 vs. median=61, range= 47-97, p<0.001). The HR group showed higher penalty scores in the Intersection task (p<0.001) and the Overtaking and ...
2018 20th Symposium on Virtual and Augmented Reality (SVR), 2018
Cooperative manipulation techniques allow multiple users to interact with an object together at t... more Cooperative manipulation techniques allow multiple users to interact with an object together at the same time. This kind of collaboration allow users to solve complex tasks that would be difficult for a single user to perform. The EGOEXO technique proposed in this paper places two collaborating users in asymmetric viewpoint positions. It was developed from the premise that simultaneous control over navigation and manipulation by the user can increase the interaction complexity. Our technique allows one of the users to follow the object being manipulated automatically while the other stays in a fixed position farther away. Our technique separates the degrees of freedom between the two users, matching the degrees to the most suitable viewpoints. Each user interacts with objects using complimentary manipulation techniques, which were chosen based on which degrees they control. EGO-EXO is implemented and evaluated through a user study to test how well it performs when compared to a similar technique when both user viewpoints are fixed.
Measuring involuntary eye movement under specific stimuli is an important way to identify disease... more Measuring involuntary eye movement under specific stimuli is an important way to identify diseases such as balance disorders. Exams based on video-oculography (VOG) equipment are able to detect horizontal and vertical displacements of the pupil. However, detecting torsional movements is still a challenge. Although conventional methods have good accuracy, their results can be influenced by artifacts, such as a torsion center displacement, interference by illumination, reflections, and changes in the pupil dilation. We propose a novel method which improves the robustness of this measurement by applying the Lucas-Kanade Pyrm (LKP) optical flow technique to the captured image, directly over the iris, rather than making a polar transformation. Retaining this additional information allows multiple features over the iris to be analyzed individually and as a group, providing correction of the torsion center displacements, filtering features with reflections and adapting to different pupil dilations before the torsion angle is calculated. The accuracy and performance of this method were evaluated by comparing it against a conventional method when detecting torsional movements on videos with a known ground truth. Moreover, a simplified version of the proposed method is also evaluated, in order to analyze the impacts of a torsion center displacement. Results show that the proposed method has higher accuracy and equivalent performance to the conventional method.
2017 IEEE Symposium on 3D User Interfaces (3DUI), 2017
This work proposes and evaluates the EGO-EXO technique for cooperative manipulation in a Collabor... more This work proposes and evaluates the EGO-EXO technique for cooperative manipulation in a Collaborative Virtual Environment (CVE). From the premise that simultaneous control over navigation and manipulation by the user can make interaction complex, this technique places two users in asymmetric viewpoint positions during the cooperative manipulation of an object, allowing one of them to follow the object. It applies the separation of degrees of freedom method between the two viewpoints to make the manipulation easier. The technique is evaluated through a user study to test its efficiency on handling cooperative manipulation. Results indicate that, for manipulation tasks that require high amplitude position control along precise orientation control, the technique performs with a lower collisions to time ratio.
Anais Pr ncipais do Simpósio Brasileiro de Computação Aplicada à Saúde (SBCAS 2015), 2015
O presente artigo propõe um método para segmentação automática de lesões de Esclerose Múltipla em... more O presente artigo propõe um método para segmentação automática de lesões de Esclerose Múltipla em imagens de Ressonância Magnética obtidas na modalidade Fluid Attenuated Inverse Recovery (FLAIR). Ao contrário do método considerado padrão ouro atual, que exige que além das imagens em FLAIR também sejam adquiridas imagens na modalidade T1, a abordagem aqui descrita visa substituir o uso das imagens T1, utilizadas na delimitação das estruturas cerebrais, pelo uso de atlas probabilísticos utilizados para os mesmos fins. Como resultados preliminares, obteve-se uma segmentação bastante aproximada do método considerado padrão ouro, o que para este trabalho em andamento indica um bom direcionamento de estudos.
Introdução: Dirigir automóvel é importante para manter a independência, autonomia e qualidade de ... more Introdução: Dirigir automóvel é importante para manter a independência, autonomia e qualidade de vida e requer a integridade das funções cognitivas, as quais tendem a diminuir com o envelhecimento, podendo interferir nas habilidades necessárias para a direção segura. Testes neuropsicológicos permitem detectar deficiências cognitivas e junto com o uso de simuladores de direção podem auxiliar a identificar o risco de acidentes e infrações. Objetivo: Investigar a relação entre o desempenho de idosos em um simulador de direção e em testes cognitivos. Métodos: Trinta e quatro condutores com mais de 65 anos foram submetidos a exercícios em um simulador de direção e avaliados cognitivamente. Resultados: Contatou-se associação entre o desempenho nas tarefas no simulador e o funcionamento cognitivo. Conclusão: O uso de testes cognitivos, em especial os que avaliam atenção e memória revelam-se promissores na identificação de idosos que possam apresentar problemas no trânsito.
One of the tools for the diagnosis of multiple sclerosis (MS) is the MRI scan. Among the acquisit... more One of the tools for the diagnosis of multiple sclerosis (MS) is the MRI scan. Among the acquisition protocols these exams are the Routine Protocol (PR) and the Specific Protocol (SP). The EP is an expensive and time consuming exam, but allows a more precise quantification of the lesions' volume. On the other hand, the PR is cheaper, however, its accuracy is lower for this task. Within this context, this work presents a study on the application of interpolation methods in order to simulate the SP exam from an PR scan. Tests conducted so far show that the interpolated tests provide a more accurate quantification of the volume of the lesions than that obtained through the PR scan.
The analysis of urine sediments (Urinalysis) is a common procedure in diagnostic laboratories, an... more The analysis of urine sediments (Urinalysis) is a common procedure in diagnostic laboratories, and allows the identification of important diseases. This procedure is usually done by a professional, which performs a visual inspection of microscope slides containing urine, aiming to identify crystals, bacteria and other relevant elements, resulting in a laborious task. The automation of this task is of great value to medicine and related areas, raising the quality and reliability of diagnosis and reducing the time spent with these tasks. This paper describes a new method for automating the analysis of urine sediments in digital images that has the main goal of finding cystine crystals. Real images obtained from a microscope and from some public image databases were used to test the developed algorithm, which demonstrated satisfactory results with 73.72% and 93.08% of sensitivity and specificity, respectively.
This work consists of the study of techniques of robotics and virtual reality to develop a simula... more This work consists of the study of techniques of robotics and virtual reality to develop a simulator that can be used in robotics schools, having an adequate visualization and a simple and intuitive way of interaction. For this, a 3D virtual environment for robotics was developed. Virtual reality resources have been incorporated to improve the visualization and to facilitate the user interaction with the environment. In order to evaluate the effectivity of the environment, user experiments were carried out on four different hardware configurations. During the simulations, the users had to create trajectories while implicitly defining reference points. From these experiments, automatic reports for the quantitative questions were generated, and questionnaires were filled for the qualitative questions. The results have shown that the use of virtual reality do helps the users in task execution, improving the visualization, reducing the time spent for the tasks and increasing the precision.
In radiology, virtual reality has emerged as a candidate to solve some issues of the area, such a... more In radiology, virtual reality has emerged as a candidate to solve some issues of the area, such as the ambient lighting and ergonomic postures when diagnosing. The goal of this study is to explore the literature of virtual reality in radiology in order to define and describe the state-of-the-art in addition to finding gaps and opportunities for future research. To do so, we carried out a systematic mapping study covering the period from January 2014 to July 2021. We initially found 329 papers to be reviewed, but after applying our exclusion criteria we ended up with 24 primary studies. Our results suggest that the use of virtual reality has grown recently in the field, however there are many gaps and opportunities to explore in the area.
Anais Estendidos do XXI Simpósio Brasileiro de Jogos e Entretenimento Digital (SBGames Estendido 2022)
Virtual characters can elicit an uncomfortable sensation usually known as Uncanny Valley (UV). Ev... more Virtual characters can elicit an uncomfortable sensation usually known as Uncanny Valley (UV). Evidence suggests that animation exacerbates the UV effect. This paper revisits the UV hypothesis to assess its effects on people’s perception of virtual characters, to try to answer the questions “What happens to the perceptual comfort if, in addition to images and videos of characters, we include those characters in an interactive Virtual Reality (VR) environment?”, and “Considering the VR environment, do people feel equally comfortable if we increase the number of characters?”. The results indicate that there are differences in the perception of scenarios with low and high densities.
Background: Age-related cognitive decline impacts cognitive abilities essential for driving. Obje... more Background: Age-related cognitive decline impacts cognitive abilities essential for driving. Objective: We aimed to measure main cognitive functions associated with a high number of traffic violations in different driving settings. Methods: Thirty-four elderly individuals, aged between 65 and 90 years, were evaluated with a driving simulator in four different settings (Intersection, Overtaking, Rain, and Malfunction tasks) and underwent a battery of cognitive tests, including memory, attention, visuospatial, and cognitive screening tests. Individuals were divided into two groups: High-risk driving (HR, top 20% of penalty points) and normal-risk driving (NR). Non-parametric group comparison and regression analysis were performed. Results: The HR group showed higher total driving penalty score compared to the NR group (median=29, range= 9-44 vs. median=61, range= 47-97, p<0.001). The HR group showed higher penalty scores in the Intersection task (p<0.001) and the Overtaking and ...
2018 20th Symposium on Virtual and Augmented Reality (SVR), 2018
Cooperative manipulation techniques allow multiple users to interact with an object together at t... more Cooperative manipulation techniques allow multiple users to interact with an object together at the same time. This kind of collaboration allow users to solve complex tasks that would be difficult for a single user to perform. The EGOEXO technique proposed in this paper places two collaborating users in asymmetric viewpoint positions. It was developed from the premise that simultaneous control over navigation and manipulation by the user can increase the interaction complexity. Our technique allows one of the users to follow the object being manipulated automatically while the other stays in a fixed position farther away. Our technique separates the degrees of freedom between the two users, matching the degrees to the most suitable viewpoints. Each user interacts with objects using complimentary manipulation techniques, which were chosen based on which degrees they control. EGO-EXO is implemented and evaluated through a user study to test how well it performs when compared to a similar technique when both user viewpoints are fixed.
Measuring involuntary eye movement under specific stimuli is an important way to identify disease... more Measuring involuntary eye movement under specific stimuli is an important way to identify diseases such as balance disorders. Exams based on video-oculography (VOG) equipment are able to detect horizontal and vertical displacements of the pupil. However, detecting torsional movements is still a challenge. Although conventional methods have good accuracy, their results can be influenced by artifacts, such as a torsion center displacement, interference by illumination, reflections, and changes in the pupil dilation. We propose a novel method which improves the robustness of this measurement by applying the Lucas-Kanade Pyrm (LKP) optical flow technique to the captured image, directly over the iris, rather than making a polar transformation. Retaining this additional information allows multiple features over the iris to be analyzed individually and as a group, providing correction of the torsion center displacements, filtering features with reflections and adapting to different pupil dilations before the torsion angle is calculated. The accuracy and performance of this method were evaluated by comparing it against a conventional method when detecting torsional movements on videos with a known ground truth. Moreover, a simplified version of the proposed method is also evaluated, in order to analyze the impacts of a torsion center displacement. Results show that the proposed method has higher accuracy and equivalent performance to the conventional method.
2017 IEEE Symposium on 3D User Interfaces (3DUI), 2017
This work proposes and evaluates the EGO-EXO technique for cooperative manipulation in a Collabor... more This work proposes and evaluates the EGO-EXO technique for cooperative manipulation in a Collaborative Virtual Environment (CVE). From the premise that simultaneous control over navigation and manipulation by the user can make interaction complex, this technique places two users in asymmetric viewpoint positions during the cooperative manipulation of an object, allowing one of them to follow the object. It applies the separation of degrees of freedom method between the two viewpoints to make the manipulation easier. The technique is evaluated through a user study to test its efficiency on handling cooperative manipulation. Results indicate that, for manipulation tasks that require high amplitude position control along precise orientation control, the technique performs with a lower collisions to time ratio.
Anais Pr ncipais do Simpósio Brasileiro de Computação Aplicada à Saúde (SBCAS 2015), 2015
O presente artigo propõe um método para segmentação automática de lesões de Esclerose Múltipla em... more O presente artigo propõe um método para segmentação automática de lesões de Esclerose Múltipla em imagens de Ressonância Magnética obtidas na modalidade Fluid Attenuated Inverse Recovery (FLAIR). Ao contrário do método considerado padrão ouro atual, que exige que além das imagens em FLAIR também sejam adquiridas imagens na modalidade T1, a abordagem aqui descrita visa substituir o uso das imagens T1, utilizadas na delimitação das estruturas cerebrais, pelo uso de atlas probabilísticos utilizados para os mesmos fins. Como resultados preliminares, obteve-se uma segmentação bastante aproximada do método considerado padrão ouro, o que para este trabalho em andamento indica um bom direcionamento de estudos.
Introdução: Dirigir automóvel é importante para manter a independência, autonomia e qualidade de ... more Introdução: Dirigir automóvel é importante para manter a independência, autonomia e qualidade de vida e requer a integridade das funções cognitivas, as quais tendem a diminuir com o envelhecimento, podendo interferir nas habilidades necessárias para a direção segura. Testes neuropsicológicos permitem detectar deficiências cognitivas e junto com o uso de simuladores de direção podem auxiliar a identificar o risco de acidentes e infrações. Objetivo: Investigar a relação entre o desempenho de idosos em um simulador de direção e em testes cognitivos. Métodos: Trinta e quatro condutores com mais de 65 anos foram submetidos a exercícios em um simulador de direção e avaliados cognitivamente. Resultados: Contatou-se associação entre o desempenho nas tarefas no simulador e o funcionamento cognitivo. Conclusão: O uso de testes cognitivos, em especial os que avaliam atenção e memória revelam-se promissores na identificação de idosos que possam apresentar problemas no trânsito.
One of the tools for the diagnosis of multiple sclerosis (MS) is the MRI scan. Among the acquisit... more One of the tools for the diagnosis of multiple sclerosis (MS) is the MRI scan. Among the acquisition protocols these exams are the Routine Protocol (PR) and the Specific Protocol (SP). The EP is an expensive and time consuming exam, but allows a more precise quantification of the lesions' volume. On the other hand, the PR is cheaper, however, its accuracy is lower for this task. Within this context, this work presents a study on the application of interpolation methods in order to simulate the SP exam from an PR scan. Tests conducted so far show that the interpolated tests provide a more accurate quantification of the volume of the lesions than that obtained through the PR scan.
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