Ettore Stella

• Italian National Research Council

The highly demanding safety standards adopted in the railway context imply that cutting-edge technologies must be used to limit accidents and ensure their complete avoidance. As such, developing integrated monitoring systems, which also exploit eXtended Reality technologies along with deep-learning-based anomaly detection techniques , becomes cruci...

Carbon Fiber Reinforced Plastic (CFRP) is going to assume more and more importance in mechanical and aerospace engineering in the near future. This is due to its intrinsic high lightness and resistance, if compared to traditional metallic materials. CFRP is characterized by a proper production and repair technology. The tool showed in this paper is...

In this paper, we present a new generation of omnidirectional automated guided vehicles (omniagv) used for transporting materials within a manufacturing factory with the ability to navigate autonomously and intelligently by interacting with the environment, including people and other entities. This robot has to be integrated into the operating envi...

Anomaly detection is a topic of interest in several areas, ranging from Industry 4.0 to Energy Management, Smart Agriculture, Cybersecurity, and Bioinformatics. In a wide sense, detecting anomalies implies finding samples generated within a process that differs from its standard data generation mechanisms. Identifying these samples is extremely imp...

Traditional microscopy has limitations. On the contrary, tomographic methods provide non-destructive 3D visualization. This paper proposes immersive exploration via virtual reality, revolutionizing scientific analysis by bridging traditional techniques with advanced methodologies for enhanced research insights.

Identifying intracellular organelles within the 3D label-free tomograms of cells’ refractive indexes recorded in flow cytometry is challenging. Here we present a method for the 3D statistical segmentation of nuclei and vacuoles in flowing cells.

In‐flow phase‐contrast tomography provides a 3D refractive index of label‐free cells in cytometry systems. Its major limitation, as with any quantitative phase imaging approach, is the lack of specificity compared to fluorescence microscopy, thus restraining its huge potentialities in single‐cell analysis and diagnostics. Remarkable results in intr...

Detecting defects in welds used in critical or non-critical industrial applications is of intense interest. Several non-destructive inspection methods are available, each allowing the preservation of the integrity of the sample under analysis. However, visual-based inspection methods are the most well-assessed, which usually require human experts t...

Assessment is a fundamental part of teaching and learning. With the advent of online learning platforms, the concept of assessment has changed. In the classical teaching methodology, the assessment is performed by an assessor, while in an online learning environment, the assessment can also take place automatically. The main purpose of this paper i...

Today extended reality focuses on itself a big attention by industrial and research communities. Many investments will be devoted to these technologies in the next years. Therefore, this technology has to give new and performant answers. On the other hand, deep learning algorithms are having a notable impact in many fields with interesting results....

Automation is a driving force in manufacturing, enabling to ensure quality and scale during production and assembly. After a slow start, civil aerospace industry efforts in automating production, assembly and testing, are gaining pace and novel technologies are being experimented for enabling automated assembly and inspection phases, which are reli...

Leather is one of the most representative materials of the leading sectors of world markets, such as fashion and luxury, interior design, automotive, thanks to its excellent properties able to guarantee its high quality. Although material of natural origin, leather undergoes numerous substantial transformations during the production process, which,...

Automated identification of parts showing defects have established itself as one of the key aspects in production factories during the second and third industrial revolutions, especially in sectors, such as the automotive, enjoying economies of scale. Automation can be exploited even in successive steps too, such as the final assembly of large manu...

Knowing an accurate passengers attendance estimation on each metro car contributes to the safely coordination and sorting the crowd-passenger in each metro station. In this work we propose a multi-head Convolutional Neural Network (CNN) architecture trained to infer an estimation of passenger attendance in a metro car. The proposed network architec...

Photo-identification is a widely used non-invasive technique in biological studies for understanding if a specimen has been seen multiple times only relying on specific unique visual characteristics. This information is essential to infer knowledge about the spatial distribution, site fidelity, abundance or habitat use of a species. Today there is...

Photo-identification is one of the best practices to estimate the abundance of cetaceans and, as such, it can help to obtain the biological information necessary to decision-making and actions to preserve the marine environment and its biodiversity. The Risso’s dolphin is one of the least-known cetacean species on a global scale, and the distinctiv...

In this paper a fast method based on laser triangulation for the estimation of the pose of a mobile robot is presented. The system is made of a camera and a laser source, placed on the front side of a robot, the Smoov ASRV, which is an autonomous vehicle able to carry, store and retrieve pallets in a smart warehouse constituted by metallic shelves....

In this paper a method based on the well-known frame theory is presented for the identification and classification of objects inside a scene. Three-dimensional (3D) point clouds have been firstly acquired using a laser triangulation system exploiting a high resolution camera, in order to derive accurate datasets for the method validation. The metho...

Digital holography is widely used in many fields for imaging, display, and metrology by exploiting its capability to furnish quantitative phase contrast maps. The entire processing pipeline that permits achievement of phase contrast images can be obtained by a cascade of numerical processing, such as zero-order and twin-image suppression, automatic...

In this paper we present an on-board Computer Vision System for the pose estimation of an Unmanned Aerial Vehicle (UAV) with respect to a human-made landing target. The proposed methodology is based on a coarse-to-fine approach to search the target marks starting from the recognition of the characteristics visible from long distances, up to the inn...

This paper presents an accurate and robust processing pipeline for merging tridimensional datasets related to railway contexts and thus producing a comprehensive 3D model of the monitored scenario. The method is made of multiple modules able to detect the rail tracks and achieve consecutive point cloud registration. A preliminary stage is aimed at...

This paper tackles the problem of people re-identification by using soft biometrics features. The method works on RGB-D data (color point clouds) to determine the best matching among a database of possible users. For each subject under testing, skeletal information in three-dimensions is used to regularize the pose and to create a skeleton standard...

In the field of NDT techniques for aeronautic components of composite materials, the development of automatic and robust approaches for defect detection is largely desirable for both safety and economic reasons. This paper introduces a novel methodology for the automatic analysis of thermal signals resulting from the application of pulsed thermogra...

Abstract The Risso’s dolphin is a widely distributed species, found in deep temperate and tropical waters. Estimates of its abundance are available in a few regions, details of its distribution are lacking, and its status in the Mediterranean Sea is ranked as Data Deficient by the IUCN Red List. In this paper, a synergy between bio-ecological analy...

The detection of anomalous behaviors of people in indoor environments is an important topic in surveillance applications, especially when low cost solutions are necessary in contexts such as long corridors of public buildings, where standard cameras with long camera view would be either ineffective or costly to implement. This paper proposes a netw...

Pulsed thermography has been used for many years to investigate the presence of subsurface defects in composite materials for aeronautics. Several methods have been proposed but only few of them include a complete automated approach for the effective defect characterization. This paper presents a novel method which approximates the thermal decays o...

Camera triggering represents an essential step for synchronizing artificial vision systems and can affect the quality of acquired images. In fact, a proper trigger signal is mandatory to synchronize in time both stand alone or multiple cameras covering large environments. In addition, indoor environments with artificial light sources can induce fli...

In this article, we tackle the problem of developing a visual framework to allow the autonomous landing of an unmanned aerial vehicle onto a platform using a single camera. Specifically, we propose a vision-based helipad detection algorithm in order to estimate the attitude of a drone on which the camera is fastened with respect to target. Since th...

We live in the era of the fourth industrial revolution, where everything - from small objects to entire factories - is smart and connected, and we are also strongly accustomed to comforts and services, but emergent questions are arising. What are the consequences of human activities on terrestrial and aquatic/marine systems? And how does the loss o...

Sports video research is a popular topic that has been applied to many prominent sports for a large spectrum of applications. In this paper we introduce a technology platform which has been developed for the tennis context, able to extract action sequences and provide support to coaches for players performance analysis during training and official...

Computer vision is steadily gaining importance in many research fields, as its applications expand from traditional fields situation analysis and scene understanding in video surveillance to other scenarios. The sportive context can represent a perfect test-bed for many machine vision algorithms because of the large availability of visual data brou...

We propose a method for solving one of the significant open issues in computer vision: material recognition. A time-of-flight range camera has been employed to analyze the characteristics of different materials. Starting from the information returned by the depth sensor, different features of interest have been extracted using transforms such as Fo...

High resolution in distance (range) measurements can be achieved by means of accurate instrumentations and precise analytical models. This paper reports an improvement in the estimation of distance measurements performed by an omnidirectional range sensor already presented in literature. This sensor exploits the principle of laser triangulation, to...

This paper presents a complete framework aimed to nondestructive inspection of composite materials. Starting from the acquisition, performed with lock-in thermography, the method flows through a set of consecutive blocks of data processing: input enhancement, feature extraction, classification and defect detection. Experimental results prove the ca...

In this article, an accurate method for the registration of point clouds returned by a 3D rangefinder is presented. The method modifies the well-known iterative closest point (ICP) algorithm by introducing the concept of deletion mask. This term is defined starting from virtual scans of the reconstructed surfaces and using inconsistencies between m...

This paper describes a complete method for monitoring indoor environments. Three-dimensional (3D) point clouds are first acquired from the environment under investigation by means of a laser range scanner in order to obtain several 3D models to be compared. Input datasets are thus registered each other exploiting a reliable variant of the iterative...

In this work a novel way for the recognition and classification of objects inside a scene, inspired by the well-known frame theory, is described. First of all, three-dimensional (3D) point clouds have been obtained using a laser triangulation system of high resolution, in order to achieve low noise datasets for the method validation. Once specific...

One of the first tasks executed by a vision system made of fixed cameras is the background (BG) subtraction and a particularly challenging context for real time applications is the athletic one because of illumination changes, moving objects and cluttered scenes. The aim of this work is to extract a BG model based on statistical likelihood able to...

In this paper, an approach based on the analysis of variance (ANOVA) for the extraction of crop marks from aerial images is improved by means of preliminary analyses and semantic processing of the extracted objects. The paper falls in the field of digitalization of images for archaeology, assisting expert users in the detection of un-excavated site...

In this paper, we propose an embedded vision system based on laser profilometry able to get the pose of a vehicle and its relative displacements with reference to the constitutive media of a structured environment. Fundamental equations for laser triangulation are developed and encoded for their actual implementation on an embedded system. It is ma...

In this paper, an accurate range sensor for the three-dimensional reconstruction of environments is designed and developed. Following the principles of laser profilometry, the device exploits a set of optical transmitters able to project a laser line on the environment. A high-resolution and high-frame-rate camera assisted by a telecentric lens col...

In the last few decades, virtual reconstruction of objects has grown interest in the field of quality control. As known, smart manufactures need automatic systems for the real-time investigation of production yields, i.e. techniques, methods and technologies devoted to the analysis of quality. In particular, high-resolution systems are required for...

We present a fast and accurate method to derive the pose of a mobile vehicle moving within bounded paths. A triangulation-based vision system made of a laser source, able to generate a line pattern, and a high speed camera is applied on the front side of an autonomous vehicle, namely the Smoov ASRV platform, which is able to store and retrieve pall...

Background (BG) modelling is a key task in every computer vision system (CVS) independently of the final purpose for which it is designed. Even if many BG approaches exist (for example Mixture of Gaussians or Eigenbackground), they can not efficiently process real time videos due to the model complexity and to the high throughput of the video flux....

Goal-LineTechnology (GLT) is a system used in football game to establish if the ball has completely crossed the goal line and contextually assisting referee in awarding a goal or not. The first aim of GLT is not to replace the institutional role of the officials, but rather to help them in highly critical situations where making the correct decisio...

In this paper a method based on the well-known frame theory is presented for the identification and classification of objects inside a scene. Three-dimensional (3D) point clouds have been firstly acquired using a laser triagulation system exploiting a high resolution camera, in order to derive accurate datasets for the method validation. The method...

In this paper a fast method based on laser triangula-tion for the estimation of the pose of a mobile robot is presented. The system is made of a camera and a laser source, placed on the front side of a robot, the Smoov ASRV, which is an autonomous vehicle able to carry, store and retrieve pallets in a smart warehouse constituted by metallic shelves...

In this paper we present a reliable method to derive the differences between indoor environments using the comparison of high-resolution range images. Samples belonging to different acquisitions are firstly reduced preserving the topology of the scenes and then registered in the same system of reference through an iterative least-squares algorithm,...

In this paper a fast and innovative three-dimensional vision system, having high resolution in the surface reconstruction, is discussed. It is based on a triangulation 3D laser scanner with a linear beam shape. The high precision (few microns) is guaranteed by very small laser line width, small camera pixel-size and proper optical properties of the...

The present invention refers to the problem of the automatic detection of events in sport field, in particular Goal/NoGoal events by signalling to the mach management, which can autonomously take the final decision upon the event. The system is not invasive for the field structures, neither it requires to interrupt the game or to modify the rules t...

In this paper, a real case study on a Goal Line Monitoring system is presented. The core of the paper is a refined ball detection algorithm that analyzes candidate ball regions to detect the ball. A decision making approach, by means of camera calibration, decides about the goal event occurrence. Differently from other similar approaches, the propo...

A high-resolution vision system for the inspection of drilling tools is presented. A triangulation-based laser scanner is used to extract a three-dimensional model of the target aimed to the fast detection and characterization of surface defects. The use of two orthogonal calibrated handlings allows the achievement of precisions of the order of few...

The environmental 3-D reconstruction is a strategic task in many contexts, above all, in infrastructure inspection and vehicle/robot automatic motion. In this paper, we present a patented sensor capable to recover 3-D data with a very high profile acquisition rate and perform an omnidirectional highly accurate environmental reconstruction: these sk...

In this paper we present a patented sensor devoted to the high precision 3D omnidirectional reconstruction. This sensor is based on the profilometer approach, but exploits a catadioptric system to get a very large field of view. After a theoretical presentation of the sensor's functionality and an analysis on its sensitivity, a designing strategy h...

Wide field of view 3-D scanners are strategic in many contexts, above all, infrastructure inspection and vehicle/robot automatic motion. In this paper we present a patented sensor able to recover three-dimensional data and perform an omnidirectional highly accurate environmental reconstruction, mainly focusing on a design strategy for setting up th...

The railway maintenance is a particular application context required in order to prevent any dangerous situation. With the growing of the high-speed railway traffic, automatic inspection systems able to detect rail defects, sleepers' anomalies, as well as missing fastening elements, become strategic since they could increase the ability in the dete...

Rail inspection is an essential task in railway maintenance and is periodically needed. Inspection is manually operated by trained human operator walking along the track searching for visual anomalies. This monitoring is unaccept-able for slowness and lack of objectivity. This paper deals with a patented Visual Inspection System for Railway mainte-...

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Rail inspection is a very important task in railway maintenance, and it is periodically needed for preventing dangerous situations. Inspection is operated manually by trained human operator walking along the track searching for visual anomalies. This monitoring is unacceptable for slowness and lack of objectivity, as the results are related to the...

In this paper, we present a vision-based method for the automatic inspection of defects on ball bearings. A supervised neural network, employing a Multilayer Perceptron trained with the BackPropagation algorithm, is applied for discriminating defects. The images of the ball bearings are first mapped to a new space, called Defect Evaluation Space, t...

This paper focuses on the problem of how data representation influences the generalization error of kernel based learning machines like support vector machines (SVM) for classification. Frame theory provides a well founded mathematical framework for representing data in many different ways. We analyze the effects of sparse and dense data representa...

The correct assessment of the condition of a railroad requires the consideration of different factors. Some factors, such as the condition of the ties, can be measured by inspecting features visible from the surface of the railway. Other factors include the condition of the ballast; it is important to recognize the critical situation in which any f...

Rail inspection is a very important task in railway maintenance and it is periodically needed for preventing dangerous situations. Inspection is operated manually by trained human operator walking along the track searching for visual anomalies. This monitoring is unacceptable for slowness and lack of objectivity, because the results are related to...

In this paper we focus on the problem of automatically detecting the absence of the fastening bolts that secure the rails to the sleepers. The proposed visual inspection system uses images acquired from a digital line scan camera installed under a train. The general performances of the system, in terms of speed and detection rate, are mainly influe...

This paper focuses on the problem of data representation for feature selection and extraction of 1D electronic nose signals. While PCA signal representation is a problem dependent method, we propose a novel approach based on frame theory where an over-complete dictionary of functions is considered in order to find the near-optimal representation of...

The paper presents a new approach for detecting and removing shadows from objects and pedestrians, since shadow removing is a fundamental step in video-surveillance systems for accurate object detection. In order to precisely remove the unwanted shadows, a novel approach is proposed, focused on the problem of representing texture information in ter...