Jan Dittmann, Andreas Breitbarth, Gunther Notni
In the last decades the relevance of forest monitoring has become increasingly relevant. Therefore, the diameter at breast height is one of the most relevant parameters of forest trees. A diameter tape measure is currently used to determine this parameter. In this study we want to digitise this and evaluate accuracy and applicability by using a photogrammetric approach. The goSCOUT3D is used as a representative for high-resolution 3D scanners with a photogrammetric approach. An everyday consumer product with a suitable camera is used for comparison. Specifically, the main camera of the...
IMEKO TC2 PhotoMet 2025
· TC2
· 2025
· 10.21014/tc2-2025.016
· Download
Valentina Bello, Irene Bassi, Cristina Nuzzi, Simone Pasinetti, Sabina Merlo
Milk is daily consumed worldwide by billions of people and it is also one of the foods most commonly subject to adulteration and counterfeiting. This paper presents a novel low-cost approach to assess milk authenticity by combining speckle pattern imaging and artificial intelligence. From the collected images, 11 statistical parameters were extracted and used to train and test a machine learning model, with the aim of distinguishing whole cow milk and 8 adulterated samples. The performances achieved by the AI-enhanced speckle pattern imaging approach (accuracy of 80%) represent a promising...
IMEKO TC2 PhotoMet 2025
· TC2
· 2025
· 10.21014/tc2-2025.015
· Download
Christina Junger, Benjamin Simon, Gunther Notni
Transparent objects challenge 3D perception in robotics, especially in navigation and human-robot collaboration. Conventional 3D sensors in the visible or near-infrared spectrum often fail to detect transparent materials due to their optical properties. Collecting real-world datasets for deep learning is difficult and time-consuming because ground truth acquisition requires complex preparation. Multimodal 3D sensors like thermal 3D cameras can automate dataset creation but are costly and need restrictive safety setups. Combining standard 3D sensors or RGB cameras with zero-shot deep learning...
IMEKO TC2 PhotoMet 2025
· TC2
· 2025
· 10.21014/tc2-2025.014
· Download
Massimo Olivero, Giuseppe Rizzelli, Chiara Bellezza Prinsi, Saverio Pellegrini, Antonino Quattrone, Francesco Tondolo, Donato Sabia, Guido Perrone, Roberto Gaudino
This work explores the application of Distributed Optical Fiber Sensing (DOFS) for structural health monitoring within the context of Building Information Modeling (BIM). The study addresses concerns about reliability and implementation of optical sensing techniques by providing, for the first time to the authors' knowledge, a technical validation of two DOFS technologies in a real framework. Strain measurements are carried out on a small reinforced concrete beam using Optical Frequency Domain Reflectometry (OFDR) and Brillouin Optical Frequency Domain Analysis (BOFDA). Both methods...
IMEKO TC2 PhotoMet 2025
· TC2
· 2025
· 10.21014/tc2-2025.013
· Download
Daniel Regner, João Facco, Moacir Wendhausen, Alice Bilbao, Tiago Loureiro Figaro da Costa Pinto, Armando Albertazzi G. Jr.
In this paper, we propose an innovative 3D reconstruction approach based on stereo vision that combines inverse triangulation with a spatiotemporal correlation algorithm. The inverse triangulation technique enables the correspondence search to be performed systematically in the object space, using a structured 3D grid centered on each point of interest (X, Y, Z). These 3D points are projected onto the image planes, and subpixel-interpolated intensities are extracted from a sequence of temporal images to compute the correlation values. For each (X, Y) tuple, the Z value is determined by the...
IMEKO TC2 PhotoMet 2025
· TC2
· 2025
· 10.21014/tc2-2025.012
· Download
Martin Richter, Maik Rosenberger, Gunther Notni
This work extends upon a novel method for detecting resin traces on forest surfaces, which is crucial for the early identification of bark beetle outbreaks in spruce and pine forests amidst climate change. The Normalized Difference Resin Index (NDRI), a Normalized Difference Vegetation Index (NDVI) like vegetation index, has been developed for the purpose of identifying resin from beetle damage. Employing a hyperspectral system with a 1000-2500 nm range, it was found that detection performance could be improved with wavelengths beyond 1700 nm, with 1720 nm and 2300 nm identified as critical...
IMEKO TC2 PhotoMet 2025
· TC2
· 2025
· 10.21014/tc2-2025.011
· Download
Valentina Di Pinto, Giovanni Gibertoni, Luigi Rovati
This study presents a performance comparison of low-cost, spray-applied reflective coatings for use on custom 3D-printed substrates, targeting visual stimulation applications such as ophthalmic prototypes. BaSO4 and TiO2 mixtures were evaluated against commercial references under broadband illumination to assess their spectral uniformity and practical applicability. While TiO2 achieved higher reflectance in the red-NIR region, BaSO4 demonstrated more balanced performance across the visible spectrum and superior adhesion. Standard white paints showed significantly lower and inconsistent...
IMEKO TC2 PhotoMet 2025
· TC2
· 2025
· 10.21014/tc2-2025.010
· Download
Paolo Diotti, Daniele Caltabiano, Anna Angela Pomarico, Giuditta Roselli, Michele Norgia
In this study, we describe a Time-of-Flight scanning LiDAR (Light Detection and Ranging) prototype, that leverages MEMS mirrors for agile beam steering and an FPGA-based processing unit for real-time 3D image reconstruction. The proposed 3D-LiDAR system is designed to operate within a range of up to 1 meter with a spatial resolution of 400 × 300 pixels at a frame rate of 30 Hz. Lidar prototype architecture consists of 3 main parts: optomechanical System; Digital Processing Unit (FPGA-based); analog front-end. Processed 3D depth maps are rendered in real-time via an HDMI interface, providing...
IMEKO TC2 PhotoMet 2025
· TC2
· 2025
· 10.21014/tc2-2025.009
· Download
Zheng Liu, Patrick Hunhold, Ziran He, Galina Polte, Elske Linß, Janice Kielbassa, Maik Rosenberger, Gunther Notni
The recycling of construction waste faces challenges in material identification due to class imbalance in hyperspectral datasets. To address this, we propose integrating a data augmentation module into the classification workflow for construction materials using short-wavelength infrared (SWIR) reflectance spectra. Experiments were conducted with Random Forest (RF) and 1D-CNN classifiers across multi-class and binary classification tasks, where the latter targeted classes commonly confused with minority categories. Various augmentation methods were tested, with the self-attention-based WGAN...
IMEKO TC2 PhotoMet 2025
· TC2
· 2025
· 10.21014/tc2-2025.008
· Download
Wang Liao, Chen Zhang, Shiyao Gao, Hongyu Chen, Hao Chen, Maik Rosenberger, Gunther Notni
Traditional 2D-based dynamic facial motion analysis methods often rely on texture features and lack depth information, raising the fundamental question: can facial motions be measured rather than inferred? This work proposes a multimodal 3D measurement-based concept for dynamic facial motion analysis, leveraging a camera system that combines a GOBO-based active stereo 3D unit with a synchronized RGB camera. A pretrained neural network extracts 2D facial landmarks, which are mapped into 3D-metric space. As proof-of-concept, 19 geometric features (e.g., distances and angles) are defined based...
IMEKO TC2 PhotoMet 2025
· TC2
· 2025
· 10.21014/tc2-2025.007
· Download