Lapo Governi

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.

Machine vision tool for real-time detection of defects on textile raw fabrics

Abstract This work describes an automated artificial vision inspection (AVI) system for real-time detection and classification of defects on textile raw fabrics. The tool (software + hardware) is directly attached to an appositely developed appraisal equipment machine (weave room monitoring system) and the inspection is performed online. The developed tool performs (1) the image acquisition of the raw fabric, (2) the extraction of some critical parameters from the acquired images, (3) an artificial neural network (ANN)-based approach able to detect and classify the most frequently occurring types of defects occurring on the raw fabric and (4) a standard image processing algorithm that allows the measurement of the geometric properties of the detected defects. The reliability of the tool is about 90% (defect detected vs. effectively existing defects), that is, similar to the performance obtained by human experts. Once detected the defects are correctly classified in 88% of cases and their geometrical properties are measured with a sub-pixel precision.

Improving surface reconstruction in shape from shading using easy-to-set boundary conditions

Minimisation techniques are commonly adopted methodologies for retrieving a 3D surface starting from its shaded representation (image), i.e., for solving the widely known shape from shading (SFS) problem. Unfortunately, depending on the imaged object to be reconstructed, retrieved surfaces often results to be completely different from the expected ones. In recent years, a number of interactive methods have been explored with the aim of improving surface reconstruction; however, since most of these methods require user interaction performed on a tentative reconstructed surface which often is significantly different from the desired one, it is advisable to increase the quality of the surface, to be further processed, as much as possible. Inspired by such techniques, the present work describes a new method for interactive retrieving of shaded object surface. The proposed approach is meant to recover the expected surface by using easy-to-set boundary conditions, so that the human-computer interaction primaril...

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.

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.

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.

Modelling and simulation of an innovative fabric coating process using artificial neural networks

A polyurethane-based fabric coating process requires a series of parameters to be set in order to meet the desired quality of the final product. Usually, the optimal setting of such parameters is performed by means of experimental tests, based on the experience of trained operators. The lack of understanding of the interaction between the coating process parameters and the final quality properties of the coated fabric encourages the development of predictive models. The main aim of the present work is to provide a predictive model of a particular coating process for forecasting the final characteristics of a coated fabric, based on the process parameters. The devised model, based on artificial neural networks, is trained and validated using a wide experimental database created with reference to an innovative coating process. Once simulated with new process parameters, the model proves to be capable of determining the best possible process parameter values to obtain the preferred coated fabric properties. By employing the developed model, a series of charts are also built that can be used to provide technicians with a practical tool for effectively selecting the process parameters.

A RGB-D based instant body-scanning solution for compact box installation

Body scanning presents unique value in delivering the first digital asset of a human body thus resulting a fundamental device for a range of applications dealing with health, fashion and fitness. Despite several body scanners are in the market, recently depth cameras such as Microsoft Kinect® have attracted the 3D community; compared with conventional 3D scanning systems, these sensors are able to capture depth and RGB data at video rate and even if quality and depth resolution are not optimal for this kind of applications, the major benefit comes from the overall acquisition speed and from the IR pattern that allows poor lighting conditions optimal acquisition. When dealing with non-rigid bodies, unfortunately, the use of a single depth camera may lead to inconsistent results mainly caused by wrong surfaces registration. With the aim of improving existing systems based on low-resolution depth cameras, the present paper describes a novel scanning system for capturing 3D full human body models by using multiple Kinect® devices in a compact setup. The system consists of an instantaneous scanning system using eight depth cameras, appropriately arranged in a compact wireframe. To validate the effectiveness of the proposed architecture, a comparison of the obtained 3D body model with the one obtained using a professional Konica Minolta Range Seven 3D scanner is also presented and possible drawbacks are hinted at.

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.