Recognizing point clouds using conditional random fields

Detecting objects in cluttered scenes is a necessary step for many robotic tasks and facilitates the interaction of the robot with its environment. Because of the availability of efficient 3D sensing devices as the Kinect, methods for the recognition of objects in 3D point clouds have gained importance during the last years. In this paper, we propose a new supervised learning approach for the recognition of objects from 3D point clouds using Conditional Random Fields, a type of discriminative, undirected probabilistic graphical model. The various features and contextual relations of the objects are described by the potential functions in the graph. Our method allows for learning and inference from unorganized point clouds of arbitrary sizes and shows significant benefit in terms of computational speed during prediction when compared to a state-of-the-art approach based on constrained optimization.Peer ReviewedPostprint (author’s final draft

From point cloud to BIM: a survey of existing approaches

International audienceIn order to handle more efficiently projects of restoration, documentation and maintenance of historical buildings, it is essentialto rely on a 3D enriched model for the building. Today, the concept of Building Information Modelling (BIM) is widely adoptedfor the semantization of digital mockups and few research focused on the value of this concept in the field of cultural heritage.In addition historical buildings are already built, so it is necessary to develop a performing approach, based on a first step ofbuilding survey, to develop a semantically enriched digital model. For these reasons, this paper focuses on this chain startingwith a point cloud and leading to the well-structured final BIM; and proposes an analysis and a survey of existing approacheson the topics of: acquisition, segmentation and BIM creation. It also, presents a critical analysis on the application of this chainin the field of cultural heritag

Review of the “ as-buit BIM ” approaches

International audienceToday, we need 3D models of heritage buildings in order to handle more efficiently projects of restoration, documentation and maintenance. In this context, developing a performing approach, based on a first phase of building survey, is a necessary step in order to build a semantically enriched digital model. For this purpose, the Building Information Modeling is an efficient tool for storing and exchanging knowledge about buildings. In order to create such a model, there are three fundamental steps: acquisition, segmentation and modeling. For these reasons, it is essential to understand and analyze this entire chain that leads to a well- structured and enriched 3D digital model. This paper proposes a survey and an analysis of the existing approaches on these topics and tries to define a new approach of semantic structuring taking into account the complexity of this chain

Fast indoor scene classification using 3D point clouds

A representation of space that includes both geometric and semantic information enables a robot to perform high-level tasks in complex environments. Identifying and categorizing environments based on onboard sensors are essential in these scenarios. The Kinect™, a 3D low cost sensor is appealing in these scenarios as it can provide rich information. The downside is the presence of large amount of information, which could lead to higher computational complexity. In this paper, we propose a methodology to efficiently classify indoor environments into semantic categories using Kinect™ data. With a fast feature extraction method along with an efficient feature selection algorithm (DEFS) and, support vector machines (SVM) classifier, we could realize a fast scene classification algorithm. Experimental results in an indoor scenario are presented including comparisons with its counterpart of commonly available 2D laser range finder data

Comparative analysis of technologies and methods for automatic construction of building information models for existing buildings

Building Information Modelling (BIM) provides an intelligent and parametric digital platform to support activities throughout the life-cycle of a building and has been used for new building construction projects nowadays. However, most existing buildings today do not have complete as-built information documents after the construction phase, nor existed meaningful BIM models. Despite the growing use of BIM models and the improvement in as-built records, missing or incomplete building information is still one of the main reasons for the low-level efficiency of building project management. Furthermore, as-built BIM modelling for existing buildings is considered to be a time-consuming process in real projects. Researchers have paid attention to systems and technologies for automated creation of as-built BIM models, but no system has achieved full automation yet. With the ultimate goal of developing a fully automated BIM model creation system, this paper summarises the state-of-the-art techniques and methods for creating as-built BIM models as the starting point, which include data capturing technologies, data processing technologies, object recognition approaches and creating as-built BIM models. Merits and limitations of each technology and method are evaluated based on intensive literature review. This paper also discusses key challenges and gaps remained unaddressed, which are identified through comparative analysis of technologies and methods currently available to support fully automated creation of as-built BIM models.published_or_final_versio

Modelado Semántico 3D de Ambientes Interiores basado en Nubes de Puntos y Relaciones Contextuales

Context: We propose a methodology to identify and label the components of a typical indoor environment in order to generate a semantic model of the scene. We are interested in identifying walls, ceilings, floors, doorways with open doors, doorways with closed doors that are recessed into walls, and partially occluded windows.Method: The elements to be identified should be flat in case of walls, floors, and ceilings and should have a rectangular shape in case of windows and doorways, which means that the indoor structure is Manhattan. The identification of these structures is determined through the analysis of the contextual relationships among them as parallelism, orthogonality, and position of the structure in the scene. Point clouds were acquired using a RGB-D device (Microsoft Kinect Sensor).Results: The obtained results show a precision of 99.03% and a recall of 95.68%, in a proprietary dataset.Conclusions: A method for 3D semantic labeling of indoor scenes based on contextual relationships among the objects is presented. Contextual rules used for classification and labeling allow a perfect understanding of the process and also an identification of the reasons why there are some errors in labeling. The time response of the algorithm is short and the accuracy attained is satisfactory. Furthermore, the computational requirements are not high.Contexto: Se propone una metodología para identificar y etiquetar los componentes de la estructura de un ambiente interior típico y así generar un modelo semántico de la escena. Nos interesamos en la identificación de: paredes, techos, suelos, puertas abiertas, puertas cerradas que forman un pequeño hueco con la pared y ventanas parcialmente ocultas.Método: Los elementos a ser identificados deben ser planos en el caso de paredes, pisos y techos y deben tener una forma rectangular en el caso de puertas y ventanas, lo que significa que la estructura del ambiente interior es Manhattan. La identificación de estas estructuras se determina mediante el análisis de las relaciones contextuales entre ellos, paralelismo, ortogonalidad y posición de la estructura en la escena. Las nubes de puntos de las escenas fueron adquiridas con un dispositivo RGB-D (Sensor Kinect de Microsoft).Resultados: Los resultados obtenidos muestran una precisión de 99.03% y una sensibilidad de 95.68%, usando una base de datos propia.Conclusiones: Se presenta un método para el etiquetado semántico 3D de escenas en interiores basado en relaciones contextuales entre los objetos. Las reglas contextuales usadas para clasificación y etiquetado permiten un buen entendimiento del proceso y, también, una identificación de las razones por las que se presentan algunos errores en el etiquetado. El tiempo de respuesta del algoritmo es corto y la exactitud alcanzada es satisfactoria. Además, los requerimientos computacionales no son altos