Moulay Akhloufi

Subsurface imaging for panel paintings inspection: A comparative study of the ultraviolet, the visible, the infrared and the terahertz spectra

Abstract Infrared (IR) reflectography has been used for many years for the detection of underdrawings on panel paintings. Advances in the fields of IR sensors and optics have impelled the wide spread use of IR reflectography by several recognized Art Museums and specialized laboratories around the World. The transparency or opacity of a painting is the result of a complex combination of the optical properties of the painting pigments and the underdrawing material, as well as the type of illumination source and the sensor characteristics. For this reason, recent researches have been directed towards the study of multispectral approaches that could provide simultaneous and complementary information of an artwork. The present work relies on non−simultaneous multispectral inspection using a set of detectors covering from the ultraviolet to the terahertz spectra. It is observed that underdrawings contrast increases with wavelength up to 1700 nm and, then, gradually decreases. In addition, it is shown that IR thermography, i.e., temperature maps or thermograms, could be used simultaneously as an alternative technique for the detection of underdrawings besides the detection of subsurface defects.

Dynamic fire modeling in Three-dimensional space

This work presents a new framework for three-dimensional reconstruction of dynamic fire fronts found in outdoor unstructured scenes. The proposed approach addresses the problem of segmenting fire front regions using color attributes and clustering techniques in order to extract salient points from stereo images. These points are then used to reconstruct their 3D position in the scene. A matching strategy is proposed to deal with mismatches due to occlusions and missing data. The proposed framework was successfully used to build 3D data part of dynamic fire fronts. This 3D information was used efficiently to estimate the approximate position of the fire front and its heading direction. The obtained results are promising and show the possibility of tracking dynamic objects with changing shapes like fire fronts in a three-dimensional space.

Three-dimensional thermography for non-destructive testing and evaluation

Abstract Three-dimensional (3D) vision based scanning for metrology and inspection applications is an area that has attracted increasing interest in the industry. This interest is driven by the recent advances in 3D technologies, which enable high precision measurements at an affordable cost. 3D vision allows for the modelling and inspection of the visible surface of objects. When it is necessary to detect subsurface defects, active infrared (IR) thermography is one of the most commonly used tools today for the non-destructive testing and evaluation (NDT&E) of materials. Fusion of these two modalities allows the simultaneous detection of surface and subsurface defects and the visualisation of these defects overlaid on the 3D model of the scanned and modelled parts or their 3D computer-aided design (CAD). In this work, we present a framework for automatically fusing 3D data (scanned or CAD) with the infrared thermal images for an NDT&E process in 3D space. The captured 3D images and their thermal infrared counterparts are aligned and fused using automatically detected features. This fusion is undergone on 3D space, thus allowing 3D visualisation of subsurface defects on a 3D model (or CAD). Additionally, the defects are extracted using image processing techniques and overlaid over their virtual position in 3D space. Their positioning at a certain distance from the part’s 3D surface is proportional to the computed depth using phase image analysis in the Fourier domain. This depth represents the real position of the detected subsurface defect and is extracted using thermograms (temporal sequence of thermal images). The results obtained are promising and show how this new technology can be used efficiently in a combined NDT&E-Metrology analysis of manufactured parts, in areas such as aerospace and automotive, among others.

Multiple spectrum vision for wildland fires

Wildland fires are considered one of the major natural risks affecting almost every country in the world. The impacts of these fires are huge in term of environmental, economic, and social losses. Experts estimate that with the climate change and global warming, we will witness an increase in the frequency and size of fires in the next years. In this paper, we will present the advances in the use of multiple spectrum computer vision to process, analyze and understand wildland fires behavior. We will introduce different multispectral technologies used in image capture, the techniques developed to detect and extract the fires from the images, and how multispectral fusion is used in the context of wildland fires. We will show our recent results using multiple multimodal stereovision systems where different modalities are combined to extract important fires characteristics in threedimensional space. Finally, we will discuss the use of UAVs to monitor fires at a larger scale.

Enhancing creativity for development of automation solutions using OTSM-TRIZ: A systematic case study in agronomic industry

The article describes a method to stimulate users’ creativity within constraint-based scenarios and OTSM-TRIZ, which allows to define the problems and partial solutions to be solved during the design process in an appropriate manner. The proposed method aims to overcome constraints and problems defined within product development and related organization resources. Indeed, if these constraints are not properly taken into account, the risk of generating unsuccessful and even ineffective solutions can be high. In this work, a method has been defined, based on the OTSM-TRIZ theory: it guides the users toward the problem solution through a mapping of both the problem to solve and the relationships existing among the problems and constraints. A step-by-step approach is used to describe and propose a systematic structure, allowing to link the conceptual solution with specific solution criteria in the automation field. The validation of the proposed method corresponds to a real case study, that is, the necessity of increasing the productivity of an operational plant for the palletizing process has been selected to discuss the method implementation. Finally, the results of the case study were considered successful, because it was not necessary to introduce high investments for solution development and implementation.