Monica Carfagni

A real-time machine-vision system for monitoring the textile raising process

This work provides an automatic and non-intrusive tool to objectively monitoring the raising process by measuring the height and the density of the fibres emerging from a raised cloth (pile). These parameters are assessed by a numerical procedure, which elaborates the images provided by an appositely developed machine-vision system. The proposed approach allows the investigation and the control of the raising process and has been validated by experimental measurements performed on a set of specimens (cloths) with several raising degrees. The comparison between the results obtained by the proposed procedure and the ones coming from a widely accepted textile-measuring device (fabric assurance by simple testing, FAST) is also provided.

From 2D to 2.5D i.e. from painting to tactile model

Display Omitted Commonly used to produce the visual effect of full 3D scene on reduced depth supports, bas relief can be successfully employed to help blind people to access inherently bi-dimensional works of art. Despite a number of methods have been proposed dealing with the issue of recovering 3D or 2.5D surfaces from single images, only a few of them explicitly address the recovery problem from paintings and, more specifically, the needs of visually impaired and blind people.The main aim of the present paper is to provide a systematic method for the semi-automatic generation of 2.5D models from paintings. Consequently, a number of ad hoc procedures are used to solve most of the typical problems arising when dealing with artistic representation of a scene. Feedbacks provided by a panel of end-users demonstrated the effectiveness of the method in providing models reproducing, using a tactile language, works of art otherwise completely inaccessible.

A CAD Program for the Automated Checkout and Design of Belleville Springs

A CAD method for the checkout and design of Belleville springs is presented. The method eliminates the need to resort to conventional trial-and-error techniques. In a matter of seconds, it rapidly and accurately checks out and designs Belleville springs, outputting the load-deflection characteristics in graphic and table formats and can generate a dimensioned drawing. To enable the designer to work in the same environment, the software has been provided with a user-friendly interface for fatigue calculation along with the characteristics of parallel/series assemblies. The algorithms developed and used for each calculation module are illustrated.

Hippin: a semiautomatic computer program for selecting hip prosthesis femoral components

This work illustrates a computer program designed to aid surgeons in selecting the hip prosthesis femoral component during the preoperation planning stage of hip replacement surgery. Starting from the processing of the patients coxo-femoral region X-ray image, the program, called Hippin, interacts with the user to outline the femoral region, including the head and the inner contour of the proximal femur. It automatically examines all possible couplings with the patients femur outlines from a database containing the outlines of the available prostheses created by digitizing the templates normally used in preoperation planning. The resulting images enable the surgeon to visually compare all the alternatives. In addition, the program provides numerical values for the distances between the physiological rotation and prosthesis centers, helping the surgeon in selecting from among the possibilities. The program has been validated by comparing the computer results with actual surgeon selections.

Determining the Loss Factor by the Power Input Method (PIM), Part 1: Numerical Investigation

Damping must be accurately determined in the design and/or optimization of vehicle and aircraft trim. Yet, owing to the complexity of the dynamic interaction among the components in trimmed panel systems, until now it has been difficult to obtain reliable damping estimates. In this work, the power input method (PIM), which compares dissipated energy to the structures strain energy, was evaluated as a damping evaluation tool. Numerical simulations were used to analyze the lumped mass system (with custom software) and the plates (with commercial finite element software) and consequently to evaluate the assumptions required to apply the PIM. It was thus possible to find a way of minimizing the effect of the assumptions on the results, whose importance would be fundamental in the successive phase involving the experimental application of the method.

Determining the Loss Factor by the Power Input Method (PIM), Part 2: Experimental Investigation with Impact Hammer Excitation

Damping must be accurately determined in the design and/or optimization of vehicle and aircraft trim. Yet, owing to the complexity of the dynamic interaction among the components in trimmed panel systems, until now it has been difficult to obtain reliable damping estimates. The power input method (PIM) was numerically investigated in Part I of this work. The results regarding how to reduce the effects of the assumptions required to apply the method were put into practice through the experimental activity with impact hammer excitation described in this work. The experimental testing was conducted on flat and bent steel plates of various sizes trimmed with damping material. A method, called the numerical updating technique (NUT), was developed to reduce the number of measuring points and the effects of the discretization on the kinetic energy estimation. Comparison of the numerical and experimental results has validated the reliability and suitability of the proposed method.

Digital Bas-Relief Design: a Novel Shape from Shading-Based Method

Design of products characterized by high stylistic content and organic shapes in the form of bas-relief (e.g. fashion accessories, commemorative plaques and coins) is traditionally performed starting from handmade drawings or photographs that are manually reproduced by highly skilled craftsmen such as sculptors and engravers and finally digitized by means of 3D scanning. Several Computer-based procedures have been devised with the aim of speeding up this process, which is considerably time consuming, subjective and costly; these are mainly based on image processing techniques such as embossing, enhancement, histogram equalization or dynamic range, also implemented in CAD-based commercial software. However, these approaches are characterized by several limitations preventing them from providing a “correct” final geometry. In view of that, the present work describes a novel method for the creation of digital bas-reliefs from a single image using a Shape From Shading (SFS) based approach with interactive ini...

Tactile representation of paintings: an early assessment of possible computer based strategies

In recent years, a number of works meant to define the criteria for translating two-dimensional art into tactile representation, to be benefit of blind and visually impaired people. Due to technology-related limitations, however, these studies mainly investigated only some kinds of possible representations (e.g. tactile diagrams). This work deals with the analysis of 4 alternative translation strategies, implemented using computer-based tools, to determine the most effective one in delivering blind people a correct perception of pictorial artworks. The outcomes of the study contribute new information to the field of tactile paintings for blind and visually impaired individuals by testing the response of a panel of potential users.

On the Performance of the Intel SR30 Depth Camera: Metrological and Critical Characterization

Specifically conceived for applications related to face analytics and tracking, scene segmentation, hand/finger tracking, gaming, augmented reality, and RGB-D cameras are nowadays used even as 3-D scanners. Despite depth cameras’ accuracy and precision are not comparable with professional 3-D scanners, they still constitute a promising device for reverse engineering (RE) applications in the close range, due to their low cost. This is particularly true for more recent devices, such as, for instance, the RealSense SR300, which promises to be among the best performing close range depth cameras in the market. Given the potentiality of this new device, and since to date a deep investigation on its performances has not been assessed in scientific literature, the main aim of this paper is to characterize and to provide metrological considerations on the Intel RealSense SR300 depth sensor when this is used as a 3-D scanner. To this end, the device sensor performances are first assessed by applying the existing normative guidelines (i.e. the one published by the Association of German Engineers - Verein Deutscher Ingenieure - VDI/VDE 2634) both to a set of raw captured depth data and to a set acquired with optimized setting of the camera. Then, further assessment of the device performances is carried out by applying some strategies proposed in the literature using optimized sensor setting, to reproduce “real life” conditions for the use as a 3-D scanner. Finally, the performance of the device is critically compared against the performance of latest short-range sensors, thus providing a useful guide, for researchers and practitioners, in an informed choice of the optimal device for their own RE application.

Vibroacoustic Optimization of Stiffening Ribs and Damping Material Distribution on Sheet Metal Parts

Vehicle noise and vibration levels are basic parameters in passenger comfort. Both static and dynamic stiffness of sheet metal parts is commonly increased by means of stiffening ribs. Vibrations are also reduced by adding a layer of damping material on the floor, the roof, the firewall and other parts of the vehicle. In common practice the panels to be treated are ribbed according to criteria based on the designers experience, rather than on well defined design procedures and are uniformly covered by a layer of damping material. However, these are not efficient design solutions, especially with regard to the effectiveness of vibration reduction and to weight containment. In this paper a novel approach to achieve an optimal distribution of stiffening ribs and damping material will be presented. The proposed method is based on a Genetic Algorithm (G.A.) procedure which takes into account both the vibroacoustic performance and the weight and cost reduction. A simple case study will be illustrated to demonstrate the capabilities of the developed procedure.