EDBT 2026 Demo / reviewers in the wild / expert
Federico Bolelli
dblp:187/7704
· DBLP profile ↗
44ranked-venue papers
11as first author
27since 2021 · last 2026
0000-0002-5299-6351ORCID · verified
Domains — the database's venue-derived domains; a paper can count in several
Graphics, computer vision, multimedia, augmented reality and games · 32 · 5 first-author · 18 since 2021Artificial intelligence and machine learning · 22 · 7 first-author · 12 since 2021Applied, interdisciplinary, general and emerging computing · 9 · 4 first-author · 7 since 2021Systems, architecture and hardware · 4 · 2 first-author · 1 since 2021Human-computer interaction and ubiquitous computing · 2 · 2 first-author
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | Enabling 8B Bitwise Autoregressive Image Generation on Edge GPUs
Enrico Vezzali, Federico Bolelli, Costantino Grana, Luca Benini, Yawei Li 0001 |
ICPR (12) | 2 |
| 2026 | FG-Tracer: Tracing Information Flow in Multimodal Large Language Models in Free-Form GenerationabstractMultimodal Large Language Models (MLLMs) have achieved impressive performance across a variety of vision–language tasks. However, their internal working mechanisms remain largely underexplored. In this work, we introduce FG-Tracer, a framework designed to analyze the information flow between visual and textual modalities in MLLMs in free-form generation. Notably, our numerically stabilized computational method enables the first systematic analysis of multimodal information flow in underexplored domains such as image captioning and chain-of-thought (CoT) reasoning. We apply FG-Tracer to three state-of-the-art MLLMs—LLaVA 1.5, LLaMA 3.2-Vision, and Qwen 2.5-VL—across three vision–language benchmarks—TextVQA, COCO 2014, and ChartQA—and we conduct a word-level analysis of multimodal integration. Our findings uncover distinct patterns of multimodal fusion across models and tasks, demonstrating that fusion dynamics are both model- and task-dependent. Overall, FG-Tracer offers a robust methodology for probing the internal mechanisms of MLLMs in free-form settings, providing new insights into their multimodal reasoning strategies. Our source code is publicly available at https://github.com/AImageLab-zip/FG-TRACER Alessia Saporita, Vittorio Pipoli, Federico Bolelli, Lorenzo Baraldi 0001, Andrea Acquaviva, Elisa Ficarra |
WACV | 3 |
| 2026 | Multi-structure segmentation in CBCT volumes: The ToothFairy2 challengeabstractCone-beam computed tomography (CBCT) is widely used for dento-maxillofacial diagnostics and treatment planning, and comprehensive multi-structure segmentation remains time-consuming, limiting large-scale, reproducible research. In this article, we present ToothFairy2, a MICCAI 2024 challenge on multi-structure segmentation in maxillofacial CBCT. The accompanying dataset comprises 530 CBCT volumes (480 public training, 50 hidden test) with expert 3D annotations of 42 classes, including maxilla, mandible, crowns, bridges, implants, inferior alveolar canals, maxillary sinuses, pharynx, and teeth labeled according to the International Tooth Numbering System (FDI). 26 international teams participated in ToothFairy2, and their methods were run and evaluated for voxel-wise multi-class segmentation using a standardized protocol. This report extends the evaluation of teeth to also investigate the current capabilities of tooth detection and FDI numbering. Furthermore, ranking stability was analyzed to assess the robustness of the final challenge outcome. Overall, challenge participants achieved consistently high performance for large, high-contrast structures such as jawbones, pharynx, and most teeth, while maxillary sinuses, dental restorations, and fine structures remain challenging due to class imbalance and metal artifacts. Analysis of tooth-related metrics further revealed that assigning correct FDI numbers was more challenging than delineating individual teeth. By releasing CBCT data, 3D annotations, baseline models, and evaluation code, ToothFairy2 establishes a long-term benchmark to drive the development of automated methods for robust, clinically meaningful multi-structure segmentation in maxillofacial CBCT. Federico Bolelli, Luca Lumetti, Niels van Nistelrooij, Shankeeth Vinayahalingam, Mattia Di Bartolomeo, Kevin Marchesini, Arrigo Pellacani, Ettore Candeloro, Gabriele Rosati, Tong Xi 0001, Fabian Isensee, Yannick Kirchhoff, Lars Krämer, Maximilian Rokuss, Constantin Ulrich, Klaus H. Maier-Hein, Yuxian Jiang, Yusheng Liu 0001, Lisheng Wang, Haoshen Wang, Zhiming Cui 0001, Zhaohong Pan, Xiaokun Liang, Ender Konukoglu, Marek Wodzinski, Henning Müller, Haipeng Mai, Xiaobing Dang, Shrajan Bhandary, Radu Grosu, Stefaan Bergé, Alexandre Anesi, Costantino Grana |
Medical Image Anal. | 1 |
| 2026 | ToothSeg: Robust Tooth Instance Segmentation and Numbering in CBCT Using Deep Learning and Self-CorrectionabstractAccurate interpretation of cone-beam computed tomography (CBCT) scans is critical for oral diagnosis and treatment planning. Existing methods for automated tooth segmentation in CBCT face challenges, such as difficulties in generalizing across imaging artifacts and anatomical variations, as well as requiring manual revisions in many cases. To address these limitations, this study introduces ToothSeg, a fully automated approach for tooth instance segmentation and numbering in CBCT using deep learning and self-correction. ToothSeg combines semantic and instance segmentation into a unified method where their respective strengths are complemented. In particular, self-correction is employed when combining the segmentations, resolving merged or split teeth and determining the optimal sequence of tooth numbers for each dental arch. We conducted a comprehensive evaluation using a diverse in-house dataset (n = 1282, 25+ devices) and the publicly available ToothFairy2 challenge dataset (n = 480, 1 device), including an ablation study, a comparison to state-of-the-art methods, and an analysis of challenging cases. Compared to an optimized semantic segmentation model, including instance segmentation and self-correction consistently improved tooth segmentation (True Positive Dice: 93.6% to 94.3%) and tooth detection and numbering (multiclass instance F1: 94.2% to 95.5%). Furthermore, ToothSeg outperformed the other methods on both datasets (True Positive Dice: $\geq$ +0.4%, multiclass instance F1: $\geq$ +1.8%), particularly for challenging cases. This study provides a promising approach for automated tooth segmentation and numbering in CBCT, which is significant for reducing manual workload and supporting scalable, data-driven research in oral and craniofacial health. Niels van Nistelrooij, Lars Krämer, Steven Kempers, Michel Beyer, Federico Bolelli, Tong Xi 0001, Stefaan Bergé, Max Heiland, Klaus H. Maier-Hein, Shankeeth Vinayahalingam, Fabian Isensee |
IEEE J. Biomed. Health Informatics | 5 |
| 2026 | A State-of-the-Art Review With Code About Connected Components Labeling on GPUsabstractThis article is about Connected Components Labeling (CCL) algorithms developed for GPU accelerators. The task itself is employed in many modern image-processing pipelines and represents a fundamental step in different scenarios, whenever object recognition is required. For this reason, a strong effort in the development of many different proposals devoted to improving algorithm performance using different kinds of hardware accelerators has been made. This paper focuses on GPU-based algorithmic solutions published in the last two decades, highlighting their distinctive traits and the improvements they leverage. The state-of-the-art review proposed is equipped with the source code, which allows to straightforwardly reproduce all the algorithms in different experimental settings. A comprehensive evaluation on multiple environments is also provided, including different operating systems, compilers, and GPUs. Our assessments are performed by means of several tests, including real-case images and synthetically generated ones, highlighting the strengths and weaknesses of each proposal. Overall, the experimental results revealed that block-based oriented algorithms outperform all the other algorithmic solutions on both 2D images and 3D volumes, regardless of the selected environment. Federico Bolelli, Stefano Allegretti, Luca Lumetti, Costantino Grana |
IEEE Trans. Parallel Distributed Syst. | 1 |
| 2025 | Tracing Information Flow in LLaMA Vision: A Step Toward Multimodal Understanding
Alessia Saporita, Vittorio Pipoli, Federico Bolelli, Lorenzo Baraldi 0001, Andrea Acquaviva, Elisa Ficarra |
CAIP (2) | 3 |
| 2025 | A Deep-Learning-Based Method for Real-Time Barcode Segmentation on Edge CPUs
Enrico Vezzali, Lorenzo Vorabbi, Costantino Grana, Federico Bolelli |
CAIP (1) | 4 |
| 2025 | Segmenting Maxillofacial Structures in CBCT VolumesabstractCone-Beam computed tomography (CBCT) is a standard imaging modality in orofacial and dental practices, providing essential 3D volumetric imaging of anatomical structures, including jawbones, teeth, sinuses, and neurovascular canals. Accurately segmenting these structures is fundamental to numerous clinical applications, such as surgical planning and implant placement. However, manual segmentation of CBCT scans is time-intensive and requires expert input, creating a demand for automated solutions through deep learning. Effective development of such algorithms relies on access to large, well-annotated datasets, yet current datasets are often privately stored or limited in scope and considered structures, especially concerning 3D annotations. This paper proposes ToothFairy2, a comprehensive, publicly accessible CBCT dataset with voxel-level 3D annotations of 42 distinct classes corresponding to maxillofacial structures. We validate the dataset by benchmarking state-of-the-art neural network models, including convolutional, transformer-based, and hybrid Mamba-Based architectures, to evaluate segmentation performance across complex anatomical regions. Our work also explores adaptations to the nnU-Net framework to optimize multi-class segmentation for maxillofacial anatomy. The proposed dataset provides a fundamental resource for advancing maxillofacial segmentation and supports future research in automated 3D image analysis in digital dentistry. Federico Bolelli, Kevin Marchesini, Niels van Nistelrooij, Luca Lumetti, Vittorio Pipoli, Elisa Ficarra, Shankeeth Vinayahalingam, Costantino Grana |
CVPR | 1 |
| 2025 | MISSRAG: Addressing the Missing Modality Challenge in Multimodal Large Language Models
Vittorio Pipoli, Alessia Saporita, Federico Bolelli, Marcella Cornia, Lorenzo Baraldi 0001, Costantino Grana, Rita Cucchiara, Elisa Ficarra |
ICCV | 3 |
| 2025 | Mosaic-SR: An Adaptive Multi-Step Super-Resolution Method For Low-Resolution 2d BarcodesabstractQR and Datamatrix codes are widely used in warehouse logistics and high-speed production pipelines. Still, distant or small barcodes often yield low-pixel-density images that are hard to read. Conventional solutions rely on costly hardware or enhanced lighting, raising expenses and potentially reducing depth of field. We propose Mosaic-SR, a multi-step, adaptive super-resolution (SR) method that devotes more computation to barcode regions than uniform backgrounds. For each patch, it predicts an uncertainty value to decide how many refinement steps are required. Our experiments show that Mosaic-SR surpasses state-of-the-art SR models on 2D barcode images, achieving higher PSNR and decoding rates in less time. All code and trained models are publicly available at https://github.com/Henvezz95/mosaic-sr Enrico Vezzali, Lorenzo Vorabbi, Costantino Grana, Federico Bolelli |
ICIP | 4 |
| 2025 | Update Your Transformer to the Latest Release: Re-Basin of Task VectorsabstractFoundation models serve as the backbone for numerous specialized models developed through fine-tuning. However, when the underlying pretrained model is updated or retrained (e.g., on larger and more curated datasets), the fine-tuned model becomes obsolete, losing its utility and requiring retraining. This raises the question: is it possible to transfer fine-tuning to a new release of the model? In this work, we investigate how to transfer fine-tuning to a new checkpoint without having to re-train, in a data-free manner. To do so, we draw principles from model re-basin and provide a recipe based on weight permutations to re-base the modifications made to the original base model, often called task vector. In particular, our approach tailors model re-basin for Transformer models, taking into account the challenges of residual connections and multi-head attention layers. Specifically, we propose a two-level method rooted in spectral theory, initially permuting the attention heads and subsequently adjusting parameters within select pairs of heads. Through extensive experiments on visual and textual tasks, we achieve the seamless transfer of fine-tuned knowledge to new pre-trained backbones without relying on a single training step or datapoint. Code is available at https://github.com/aimagelab/TransFusion. Filippo Rinaldi, Giacomo Capitani, Lorenzo Bonicelli, Donato Crisostomi, Federico Bolelli, Elisa Ficarra, Emanuele Rodolà, Simone Calderara, Angelo Porrello |
ICML | 5 |
| 2025 | U-Net Transplant: The Role of Pre-training for Model Merging in 3D Medical Segmentation
Luca Lumetti, Giacomo Capitani, Elisa Ficarra, Simone Calderara, Costantino Grana, Angelo Porrello, Federico Bolelli |
MICCAI (16) | 7 |
| 2025 | IM-Fuse: A Mamba-Based Fusion Block for Brain Tumor Segmentation with Incomplete Modalities
Vittorio Pipoli, Alessia Saporita, Kevin Marchesini, Costantino Grana, Elisa Ficarra, Federico Bolelli |
MICCAI (8) | 6 |
| 2025 | Towards Unbiased Continual Learning: Avoiding Forgetting in the Presence of Spurious CorrelationsabstractContinual Learning (CL) has emerged as a paramount area in Artificial Intelligence (AI) because of its ability to learn multiple tasks sequentially without significant performance degradation. Despite the growing interest in CL frameworks, a critical aspect must be addressed: the inherent biases within training data. In this work, we show that, if overlooked, these biases can significantly impair the efficacy of continual learning models by inducing reliance on suboptimal shortcuts during data stream and memory retention, exacerbating catastrophic forgetting. In response, we present Learning without Shortcuts (LwS), which sets forth two primary objectives: (i) to identify and mitigate the exploitation of spurious correlations within the data stream and (ii) to develop a novel mechanism that constructs a fair memory buffer used in replay-based CL strategies. Our buffer construction strategy exploits the model confidence in a given example to balance the portion of samples per class, hence their contribution when replay activates. Unlike existing methods, LwS is agnostic to protected attributes, and results highlight that the proposed solution is indeed resilient to spurious correlations in CL settings. Code is available at https://github.com/aimagelab/mammoth. Giacomo Capitani, Lorenzo Bonicelli, Angelo Porrello, Federico Bolelli, Simone Calderara, Elisa Ficarra |
WACV | 4 |
| 2025 | Semantically Conditioned Prompts for Visual Recognition Under Missing Modality ScenariosabstractThis paper tackles the domain of multimodal prompting for visual recognition, specifically when dealing with missing modalities through multimodal Transformers. It presents two main contributions: (i) we introduce a novel prompt learning module which is designed to produce sample-specific prompts and (ii) we show that modalityagnostic prompts can effectively adjust to diverse missing modality scenarios. Our model, termed SCP, exploits the semantic representation of available modalities to query a learnable memory bank, which allows the generation of prompts based on the semantics of the input. Notably, SCP distinguishes itself from existing methodologies for its capacity of self-adjusting to both the missing modality scenario and the semantic context of the input, without prior knowledge about the specific missing modality and the number of modalities. Through extensive experiments, we show the effectiveness of the proposed prompt learning framework and demonstrate enhanced performance and robustness across a spectrum of missing modality cases. Our source code is available at https://github.com/vittoriopipoli/SCP_WACV2025. Vittorio Pipoli, Federico Bolelli, Sara Sarto, Marcella Cornia, Lorenzo Baraldi 0001, Costantino Grana, Rita Cucchiara, Elisa Ficarra |
WACV | 2 |
| 2025 | State-of-the-art review and benchmarking of barcode localization methodsabstractBarcodes, despite their long history, remain an essential technology in supply chain management. In addition, barcodes have found extensive use in industrial engineering, particularly in warehouse automation, component tracking, and robot guidance. To detect a barcode in an image, multiple algorithms have been proposed in the literature, with a significant increase of interest in the topic since the rise of deep learning. However, research in the field suffers from many limitations, including the scarcity of public datasets and code implementations which hinders the reproducibility and reliability of published results. For this reason, we developed “BarBeR” (Barcode Benchmark Repository), a benchmark designed for testing and comparing barcode detection algorithms. This benchmark includes the code implementation of various detection algorithms for barcodes, along with a suite of useful metrics. Among the supported localization methods, there are multiple deep-learning detection models, that will be used to assess the recent contributions of Artificial Intelligence to this field. In addition, we provide a large, annotated dataset of 8 748 barcode images, combining multiple public barcode datasets with standardized annotation formats for both detection and segmentation tasks. Finally, we provide a thorough summary of the history and literature on barcode localization and share the results obtained from running the benchmark on our dataset, offering valuable insights into the performance of different algorithms when applied to real-world problems. Enrico Vezzali, Federico Bolelli, Stefano Santi, Costantino Grana |
Eng. Appl. Artif. Intell. | 2 |
| 2025 | Segmenting the Inferior Alveolar Canal in CBCTs Volumes: The ToothFairy ChallengeabstractIn recent years, several algorithms have been developed for the segmentation of the Inferior Alveolar Canal (IAC) in Cone-Beam Computed Tomography (CBCT) scans. However, the availability of public datasets in this domain is limited, resulting in a lack of comparative evaluation studies on a common benchmark. To address this scientific gap and encourage deep learning research in the field, the ToothFairy challenge was organized within the MICCAI 2023 conference. In this context, a public dataset was released to also serve as a benchmark for future research. The dataset comprises 443 CBCT scans, with voxel-level annotations of the IAC available for 153 of them, making it the largest publicly available dataset of its kind. The participants of the challenge were tasked with developing an algorithm to accurately identify the IAC using the 2D and 3D-annotated scans. This paper presents the details of the challenge and the contributions made by the most promising methods proposed by the participants. It represents the first comprehensive comparative evaluation of IAC segmentation methods on a common benchmark dataset, providing insights into the current state-of-the-art algorithms and outlining future research directions. Furthermore, to ensure reproducibility and promote future developments, an open-source repository that collects the implementations of the best submissions was released. Federico Bolelli, Luca Lumetti, Shankeeth Vinayahalingam, Mattia Di Bartolomeo, Arrigo Pellacani, Kevin Marchesini, Niels van Nistelrooij, Pieter van Lierop, Tong Xi 0001, Yusheng Liu 0001, Rui Xin 0003, Tao Yang 0037, Lisheng Wang, Haoshen Wang, Chenfan Xu, Zhiming Cui 0001, Marek Wodzinski, Henning Müller, Yannick Kirchhoff, Maximilian Rokuss, Klaus H. Maier-Hein, Jae-Hwan Han, Wan Kim, Hong-Gi Ahn, Tomasz Szczepanski, Michal K. Grzeszczyk, Przemyslaw Korzeniowski, Vicent Caselles, Xavier Paolo Burgos-Artizzu, Ferran Prados, Stefaan Bergé, Bram van Ginneken, Alexandre Anesi, Costantino Grana |
IEEE Trans. Medical Imaging | 1 |
| 2024 | Investigating the ABCDE Rule in Convolutional Neural Networks
Federico Bolelli, Luca Lumetti, Kevin Marchesini, Ettore Candeloro, Costantino Grana |
ICPR (13) | 1 |
| 2024 | Location Matters: Harnessing Spatial Information to Enhance the Segmentation of the Inferior Alveolar Canal in CBCTs
Luca Lumetti, Vittorio Pipoli, Federico Bolelli, Elisa Ficarra, Costantino Grana |
ICPR (28) | 3 |
| 2024 | Identifying Impurities in Liquids of Pharmaceutical Vials
Gabriele Rosati, Kevin Marchesini, Luca Lumetti, Federica Sartori, Beatrice Balboni, Filippo Begarani, Luca Vescovi, Federico Bolelli, Costantino Grana |
ICPR (17) | 8 |
| 2024 | BarBeR: A Barcode Benchmarking Repository
Enrico Vezzali, Federico Bolelli, Stefano Santi, Costantino Grana |
ICPR (17) | 2 |
| 2024 | ClusterFix: A Cluster-Based Debiasing Approach without Protected-Group SupervisionabstractThe failures of Deep Networks can sometimes be ascribed to biases in the data or algorithmic choices. Existing debiasing approaches exploit prior knowledge to avoid unintended solutions; we acknowledge that, in real-world settings, it could be unfeasible to gather enough prior information to characterize the bias, or it could even raise ethical considerations. We hence propose a novel debiasing approach, termed ClusterFix, which does not require any external hint about the nature of biases. Such an approach alters the standard empirical risk minimization and introduces a per-example weight, encoding how critical and far from the majority an example is. Notably, the weights consider how difficult it is for the model to infer the correct pseudo-label, which is obtained in a self-supervised manner by dividing examples into multiple clusters. Extensive experiments show that the misclassification error incurred in identifying the correct cluster allows for identifying examples prone to bias-related issues. As a result, our approach outperforms existing methods on standard benchmarks for bias removal and fairness. Giacomo Capitani, Federico Bolelli, Angelo Porrello, Simone Calderara, Elisa Ficarra |
WACV | 2 |
| 2024 | A Graph-Based Multi-Scale Approach With Knowledge Distillation for WSI ClassificationabstractThe usage of Multi Instance Learning (MIL) for classifying Whole Slide Images (WSIs) has recently increased. Due to their gigapixel size, the pixel-level annotation of such data is extremely expensive and time-consuming, practically unfeasible. For this reason, multiple automatic approaches have been raised in the last years to support clinical practice and diagnosis. Unfortunately, most state-of-the-art proposals apply attention mechanisms without considering the spatial instance correlation and usually work on a single-scale resolution. To leverage the full potential of pyramidal structured WSI, we propose a graph-based multi-scale MIL approach, DAS-MIL. Our model comprises three modules: i) a self-supervised feature extractor, ii) a graph-based architecture that precedes the MIL mechanism and aims at creating a more contextualized representation of the WSI structure by considering the mutual (spatial) instance correlation both inter and intra-scale. Finally, iii) a (self) distillation loss between resolutions is introduced to compensate for their informative gap and significantly improve the final prediction. The effectiveness of the proposed framework is demonstrated on two well-known datasets, where we outperform SOTA on WSI classification, gaining a +2.7% AUC and +3.7% accuracy on the popular Camelyon16 benchmark. Gianpaolo Bontempo, Federico Bolelli, Angelo Porrello, Simone Calderara, Elisa Ficarra |
IEEE Trans. Medical Imaging | 2 |
| 2023 | DAS-MIL: Distilling Across Scales for MIL Classification of Histological WSIs
Gianpaolo Bontempo, Angelo Porrello, Federico Bolelli, Simone Calderara, Elisa Ficarra |
MICCAI (1) | 3 |
| 2022 | Improving Segmentation of the Inferior Alveolar Nerve through Deep Label PropagationabstractMany recent works in dentistry and maxillofacial imagery focused on the Inferior Alveolar Nerve (IAN) canal detection. Unfortunately, the small extent of available 3D maxillofacial datasets has strongly limited the performance of deep learning-based techniques. On the other hand, a huge amount of sparsely annotated data is produced every day from the regular procedures in the maxillofacial practice. Despite the amount of sparsely labeled images being significant, the adoption of those data still raises an open problem. Indeed, the deep learning approach frames the presence of dense annotations as a crucial factor. Recent efforts in literature have hence focused on developing label propagation techniques to expand sparse annotations into dense labels. However, the proposed methods proved only marginally effective for the purpose of segmenting the alveolar nerve in CBCT scans. This paper exploits and publicly releases a new 3D densely annotated dataset, through which we are able to train a deep label propagation model which obtains better results than those available in literature. By combining a segmentation model trained on the 3D annotated data and label propagation, we significantly improve the state of the art in the Inferior Alveolar Nerve segmentation. Marco Cipriano, Stefano Allegretti, Federico Bolelli, Federico Pollastri, Costantino Grana |
CVPR | 3 |
| 2022 | One DAG to Rule Them AllabstractIn this paper, we present novel strategies for optimizing the performance of many binary image processing algorithms. These strategies are collected in an open-source framework, GRAPHGEN, that is able to automatically generate optimized C++ source code implementing the desired optimizations. Simply starting from a set of rules, the algorithms introduced with the GRAPHGEN framework can generate decision trees with minimum average path-length, possibly considering image pattern frequencies, apply state prediction and code compression by the use of Directed Rooted Acyclic Graphs (DRAGs). Moreover, the proposed algorithmic solutions allow to combine different optimization techniques and significantly improve performance. Our proposal is showcased on three classical and widely employed algorithms (namely Connected Components Labeling, Thinning, and Contour Tracing). When compared to existing approaches -in 2D and 3D-, implementations using the generated optimal DRAGs perform significantly better than previous state-of-the-art algorithms, both on CPU and GPU. Federico Bolelli, Stefano Allegretti, Costantino Grana |
IEEE Trans. Pattern Anal. Mach. Intell. | 1 |
| 2021 | A deep analysis on high-resolution dermoscopic image classificationabstractAbstract Convolutional neural networks (CNNs) have been broadly employed in dermoscopic image analysis, mainly as a result of the large amount of data gathered by the International Skin Imaging Collaboration (ISIC). As in many other medical imaging domains, state‐of‐the‐art methods take advantage of architectures developed for other tasks, frequently assuming full transferability between enormous sets of natural images (e.g. ImageNet) and dermoscopic images, which is not always the case. A comprehensive analysis on the effectiveness of state‐of‐the‐art deep learning techniques when applied to dermoscopic image analysis is provided. To achieve this goal, the authors consider several CNNs architectures and analyse how their performance is affected by the size of the network, image resolution, data augmentation process, amount of available data, and model calibration. Moreover, taking advantage of the analysis performed, a novel ensemble method to further increase the classification accuracy is designed. The proposed solution achieved the third best result in the 2019 official ISIC challenge, with an accuracy of 0.593. Federico Pollastri, Mario Parreño, Juan Maroñas Molano, Federico Bolelli, Roberto Paredes, Daniel Ramos-Castro, Costantino Grana |
IET Comput. Vis. | 4 |
| 2020 | Supporting Skin Lesion Diagnosis with Content-Based Image RetrievalabstractIn recent years, many attempts have been dedicated to the creation of automated devices that could assist both expert and beginner dermatologists towards fast and early diagnosis of skin lesions. Tasks such as skin lesion classification and segmentation have been extensively addressed with deep learning algorithms, which in some cases reach a diagnostic accuracy comparable to that of expert physicians. However, the general lack of interpretability and reliability severely hinders the ability of those approaches to actually support dermatologists in the diagnosis process. In this paper a novel skin image retrieval system is presented, which exploits features extracted by Convolutional Neural Networks to gather similar images from a publicly available dataset, in order to assist the diagnosis process of both expert and novice practitioners. In the proposed framework, ResNet-50 is initially trained for the classification of dermoscopic images; then, the feature extraction part is isolated, and an embedding network is built on top of it. The embedding learns an alternative representation, which allows to check image similarity by means of a distance measure. Experimental results reveal that the proposed method is able to select meaningful images, which can effectively boost the classification accuracy of human dermatologists. Stefano Allegretti, Federico Bolelli, Federico Pollastri, Sabrina Longhitano, Giovanni Pellacani, Costantino Grana |
ICPR | 2 |
| 2020 | The DeepHealth Toolkit: A Unified Framework to Boost Biomedical ApplicationsabstractGiven the overwhelming impact of machine learning on the last decade, several libraries and frameworks have been developed in recent years to simplify the design and training of neural networks, providing array-based programming, automatic differentiation and user-friendly access to hardware accelerators. None of those tools, however, was designed with native and transparent support for Cloud Computing or heterogeneous High-Performance Computing (HPC). The DeepHealth Toolkit is an open source Deep Learning toolkit aimed at boosting productivity of data scientists operating in the medical field by providing a unified framework for the distributed training of neural networks, which is able to leverage hybrid HPC and cloud environments in a transparent way for the user. The toolkit is composed of a Computer Vision library, a Deep Learning library, and a front-end for non-expert users; all of the components are focused on the medical domain, but they are general purpose and can be applied to any other field. In this paper, the principles driving the design of the DeepHealth libraries are described, along with details about the implementation and the interaction between the different elements composing the toolkit. Finally, experiments on common benchmarks prove the efficiency of each separate component and of the DeepHealth Toolkit overall. Michele Cancilla, Laura Canalini, Federico Bolelli, Stefano Allegretti, Salvador Carrión-Ponz, Roberto Paredes, Jon Ander Gómez, Simone Leo, Marco Enrico Piras, Luca Pireddu, Asaf Badouh, Santiago Marco-Sola, Lluc Alvarez, Miquel Moretó, Costantino Grana |
ICPR | 3 |
| 2020 | Confidence Calibration for Deep Renal Biopsy Immunofluorescence Image ClassificationabstractWith this work we tackle immunofluorescence classification in renal biopsy, employing state-of-the-art Convolutional Neural Networks. In this setting, the aim of the probabilistic model is to assist an expert practitioner towards identifying the location pattern of antibody deposits within a glomerulus. Since modern neural networks often provide overconfident outputs, we stress the importance of having a reliable prediction, demonstrating that Temperature Scaling (TS), a recently introduced re-calibration technique, can be successfully applied to immunofluorescence classification in renal biopsy. Experimental results demonstrate that the designed model yields good accuracy on the specific task, and that TS is able to provide reliable probabilities, which are highly valuable for such a task given the low inter-rater agreement. Federico Pollastri, Juan Maroñas Molano, Federico Bolelli, Giulia Ligabue, Roberto Paredes, Riccardo Magistroni, Costantino Grana |
ICPR | 3 |
| 2020 | A Heuristic-Based Decision Tree for Connected Components Labeling of 3D VolumesabstractConnected Components Labeling represents a fundamental step for many Computer Vision and Image Processing pipelines. Since the first appearance of the task in the sixties, many algorithmic solutions to optimize the computational load needed to label an image have been proposed. Among them, block-based scan approaches and decision trees revealed to be some of the most valuable strategies. However, due to the cost of the manual construction of optimal decision trees and the computational limitations of automatic strategies employed in the past, the application of blocks and decision trees has been restricted to small masks, and thus to 2D algorithms. With this paper we present a novel heuristic algorithm based on decision tree learning methodology, called Entropy Partitioning Decision Tree (EPDT). It allows to compute near-optimal decision trees for large scan masks. Experimental results demonstrate that algorithms based on the generated decision trees outperform state-of-the-art competitors. Maximilian Söchting, Stefano Allegretti, Federico Bolelli, Costantino Grana |
ICPR | 3 |
| 2020 | Augmenting data with GANs to segment melanoma skin lesions
Federico Pollastri, Federico Bolelli, Roberto Paredes, Costantino Grana |
Multim. Tools Appl. | 2 |
| 2020 | Spaghetti Labeling: Directed Acyclic Graphs for Block-Based Connected Components LabelingabstractConnected Components Labeling is an essential step of many Image Processing and Computer Vision tasks. Since the first proposal of a labeling algorithm, which dates back to the sixties, many approaches have optimized the computational load needed to label an image. In particular, the use of decision forests and state prediction have recently appeared as valuable strategies to improve performance. However, due to the overhead of the manual construction of prediction states and the size of the resulting machine code, the application of these strategies has been restricted to small masks, thus ignoring the benefit of using a block-based approach. In this paper, we combine a block-based mask with state prediction and code compression: the resulting algorithm is modeled as a Directed Rooted Acyclic Graph with multiple entry points, which is automatically generated without manual intervention. When tested on synthetic and real datasets, in comparison with optimized implementations of state-of-the-art algorithms, the proposed approach shows superior performance, surpassing the results obtained by all compared approaches in all settings. Federico Bolelli, Stefano Allegretti, Lorenzo Baraldi 0001, Costantino Grana |
IEEE Trans. Image Process. | 1 |
| 2020 | Optimized Block-Based Algorithms to Label Connected Components on GPUsabstractConnected Components Labeling (CCL) is a crucial step of several image processing and computer vision pipelines. Many efficient sequential strategies exist, among which one of the most effective is the use of a block-based mask to drastically cut the number of memory accesses. In the last decade, aided by the fast development of Graphics Processing Units (GPUs), a lot of data parallel CCL algorithms have been proposed along with sequential ones. Applications that entirely run in GPU can benefit from parallel implementations of CCL that allow to avoid expensive memory transfers between host and device. In this paper, two new eight-connectivity CCL algorithms are proposed, namely Block-based Union Find (BUF) and Block-based Komura Equivalence (BKE). These algorithms optimize existing GPU solutions introducing a block-based approach. Extensions for three-dimensional datasets are also discussed. In order to produce a fair comparison with previously proposed alternatives, YACCLAB, a public CCL benchmarking framework, has been extended and made suitable for evaluating also GPU algorithms. Moreover, three-dimensional datasets have been added to its collection. Experimental results on real cases and synthetically generated datasets demonstrate the superiority of the new proposals with respect to state-of-the-art, both on 2D and 3D scenarios. Stefano Allegretti, Federico Bolelli, Costantino Grana |
IEEE Trans. Parallel Distributed Syst. | 2 |
| 2019 | How Does Connected Components Labeling with Decision Trees Perform on GPUs?
Stefano Allegretti, Federico Bolelli, Michele Cancilla, Federico Pollastri, Laura Canalini, Costantino Grana |
CAIP (1) | 2 |
| 2019 | Skin Lesion Segmentation Ensemble with Diverse Training Strategies
Laura Canalini, Federico Pollastri, Federico Bolelli, Michele Cancilla, Stefano Allegretti, Costantino Grana |
CAIP (1) | 3 |
| 2019 | M-VAD names: a dataset for video captioning with naming
Stefano Pini, Marcella Cornia, Federico Bolelli, Lorenzo Baraldi 0001, Rita Cucchiara |
Multim. Tools Appl. | 3 |
| 2018 | Monitoring the Effectiveness of Clinical Guidelines: Is the Recommendation Still Valid?abstractObjectives: A guideline means a protocol designed to help the decision in health system. Whether the protocol is still available for the recent input data is important. The aim of this study is to find a way to monitor the medical guideline, which could help the physician to find out whether the medical guideline is valid for the new patients or a different group of population, and when it should be maintained or updated. Methods: Proportion is the most important variable in diagnostic test. We simulated several pairs of data sets with different proportions. One of each pair was standard and the other had the proportion changed. Two diagnostic tasks had been comparing to find the delay in sample sizes for change detection. Two data management models were used, one of which was acquiring all data before and the other was sliding windows of a fixed size which acquired the most recent samples. Results: The sample sizes for delay detection were calculated with different levels in proportion and changes, and showed with 95% confidence level for estimating. The results also indicate that the sliding window model gave less sample sizes of delay which means more effective. Conclusion: The proper sample sizes could be chosen based on statistical principles in order to estimate the exact change point when it happens, which could help clinicians while monitoring clinical guidelines. Federico Bolelli, Federico Pollastri, Roberto Paredes |
CBMS | 1 |
| 2018 | Improving Skin Lesion Segmentation with Generative Adversarial NetworksabstractThis paper proposes a novel strategy that employs Generative Adversarial Networks (GANs) to augment data in the image segmentation field, and a Convolutional-Deconvolutional Neural Network (CDNN) to automatically generate lesion segmentation mask from dermoscopic images. Training the CDNN with our GAN generated data effectively improves the state-of-the-art. Federico Bolelli, Federico Pollastri, Roberto Paredes, Costantino Grana |
CBMS | 1 |
| 2018 | Connected Components Labeling on DRAGsabstractIn this paper we introduce a new Connected Components Labeling (CCL) algorithm which exploits a novel approach to model decision problems as Directed Acyclic Graphs with a root, which will be called Directed Rooted Acyclic Graphs (DRAGs). This structure supports the use of sets of equivalent actions, as required by CCL, and optimally leverages these equivalences to reduce the number of nodes (decision points). The advantage of this representation is that a DRAG, differently from decision trees usually exploited by the state-of-the-art algorithms, will contain only the minimum number of nodes required to reach the leaf corresponding to a set of condition values. This combines the benefits of using binary decision trees with a reduction of the machine code size. Experiments show a consistent improvement of the execution time when the model is applied to CCL. Federico Bolelli, Lorenzo Baraldi 0001, Michele Cancilla, Costantino Grana |
ICPR | 1 |
| 2018 | Optimizing GPU-Based Connected Components Labeling AlgorithmsabstractConnected Components Labeling (CCL) is a fundamental image processing technique, widely used in various application areas. Computational throughput of Graphical Processing Units (GPUs) makes them eligible for such a kind of algorithms. In the last decade, many approaches to compute CCL on GPUs have been proposed. Unfortunately, most of them have focused on 4-way connectivity neglecting the importance of 8-way connectivity. This paper aims to extend state-of-the-art GPU-based algorithms from 4 to 8-way connectivity and to improve them with additional optimizations. Experimental results revealed the effectiveness of the proposed strategies. Stefano Allegretti, Federico Bolelli, Michele Cancilla, Costantino Grana |
IPAS | 2 |
| 2018 | A Hierarchical Quasi-Recurrent approach to Video CaptioningabstractVideo captioning has picked up a considerable attention thanks to the ability of Recurrent Neural Networks to extrapolate an encoded representation of the input video, and then use it to generate a description. We propose a recurrent encoding approach able to find and exploit the layered design of the video. Differently from the established encoder-decoder procedure, in which a video is repeatedly encoded by a recurrent layer, we employ revised Quasi-Recurrent Neural Networks. We further extend their basic cell with a boundary detector in order to recognize discontinuous segments boundaries and likewise correct the temporal connections of the encoding layer accordingly. Experiments, on the Montreal Video Annotation dataset, demonstrate that our approach can find suitable levels of representation of the input information, while reducing the computational requirements. Federico Bolelli, Lorenzo Baraldi 0001, Federico Pollastri, Costantino Grana |
IPAS | 1 |
| 2016 | Optimized Connected Components Labeling with Pixel Prediction
Costantino Grana, Lorenzo Baraldi 0001, Federico Bolelli |
ACIVS | 3 |
| 2016 | YACCLAB - Yet Another Connected Components Labeling BenchmarkabstractThe problem of labeling the connected components (CCL) of a binary image is well-defined and several proposals have been presented in the past. Since an exact solution to the problem exists and should be mandatory provided as output, algorithms mainly differ on their execution speed. In this paper, we propose and describe YACCLAB, Yet Another Connected Components Labeling Benchmark. Together with a rich and varied dataset, YACCLAB contains an open source platform to test new proposals and to compare them with publicly available competitors. Textual and graphical outputs are automatically generated for three kinds of test, which analyze the methods from different perspectives. The fairness of the comparisons is guaranteed by running on the same system and over the same datasets. Examples of usage and the corresponding comparisons among state-of-the-art techniques are reported to confirm the potentiality of the benchmark. Costantino Grana, Federico Bolelli, Lorenzo Baraldi 0001, Roberto Vezzani |
ICPR | 2 |