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Sobre

Sobre

Ricardo Cruz trabalhou em vários de tópicos de machine learning, com particular ênfase em aspectos teóricos de deep learning e visão computacional – com mais de 20 publicações e mais de 100 citações em tópicos como: • adaptação de modelos de ranking para class imbalance; • tornar as redes neurais convolucionais invariantes ao background; • torná-las mais rápidos ajustando o esforço computacional a cada imagem; • losses para regressão ordinal. É investigador pós-doutorado em condução autónoma na Faculdade de Engenharia da Universidade do Porto e investigador no INESC TEC desde 2015, onde a sua investigação lhe valeu o doutoramento em ciências da computação em 2021. É licenciado em informática. ciências e um mestrado em matemática aplicada. É frequentemente convidado para lecionar na Faculdade de Engenharia da Universidade do Porto, onde obteve um prémio pedagógico.

Tópicos
de interesse
Detalhes

Detalhes

  • Nome

    Ricardo Pereira Cruz
  • Cargo

    Investigador Auxiliar
  • Desde

    01 outubro 2013
001
Publicações

2024

Active Supervision: Human in the Loop

Autores
Cruz, RPM; Shihavuddin, ASM; Maruf, MH; Cardoso, JS;

Publicação
PROGRESS IN PATTERN RECOGNITION, IMAGE ANALYSIS, COMPUTER VISION, AND APPLICATIONS, CIARP 2023, PT I

Abstract
After the learning process, certain types of images may not be modeled correctly because they were not well represented in the training set. These failures can then be compensated for by collecting more images from the real-world and incorporating them into the learning process - an expensive process known as active learning. The proposed twist, called active supervision, uses the model itself to change the existing images in the direction where the boundary is less defined and requests feedback from the user on how the new image should be labeled. Experiments in the context of class imbalance show the technique is able to increase model performance in rare classes. Active human supervision helps provide crucial information to the model during training that the training set lacks.

2024

YOLOMM - You Only Look Once for Multi-modal Multi-tasking

Autores
Campos, F; Cerqueira, FG; Cruz, RPM; Cardoso, JS;

Publicação
PROGRESS IN PATTERN RECOGNITION, IMAGE ANALYSIS, COMPUTER VISION, AND APPLICATIONS, CIARP 2023, PT I

Abstract
Autonomous driving can reduce the number of road accidents due to human error and result in safer roads. One important part of the system is the perception unit, which provides information about the environment surrounding the car. Currently, most manufacturers are using not only RGB cameras, which are passive sensors that capture light already in the environment but also Lidar. This sensor actively emits laser pulses to a surface or object and measures reflection and time-of-flight. Previous work, YOLOP, already proposed a model for object detection and semantic segmentation, but only using RGB. This work extends it for Lidar and evaluates performance on KITTI, a public autonomous driving dataset. The implementation shows improved precision across all objects of different sizes. The implementation is entirely made available: https://github.com/filipepcampos/yolomm.

2024

Condition Invariance for Autonomous Driving by Adversarial Learning

Autores
Silva, DTE; Cruz, RPM;

Publicação
PROGRESS IN PATTERN RECOGNITION, IMAGE ANALYSIS, COMPUTER VISION, AND APPLICATIONS, CIARP 2023, PT I

Abstract
Object detection is a crucial task in autonomous driving, where domain shift between the training and the test set is one of the main reasons behind the poor performance of a detector when deployed. Some erroneous priors may be learned from the training set, therefore a model must be invariant to conditions that might promote such priors. To tackle this problem, we propose an adversarial learning framework consisting of an encoder, an object-detector, and a condition-classifier. The encoder is trained to deceive the condition-classifier and aid the object-detector as much as possible throughout the learning stage, in order to obtain highly discriminative features. Experiments showed that this framework is not very competitive regarding the trade-off between precision and recall, but it does improve the ability of the model to detect smaller objects and some object classes.

2023

Rethinking low-cost microscopy workflow: Image enhancement using deep based Extended Depth of Field methods

Autores
Albuquerque, T; Rosado, L; Cruz, RPM; Vasconcelos, MJM; Oliveira, T; Cardoso, JS;

Publicação
Intell. Syst. Appl.

Abstract
Microscopic techniques in low-to-middle income countries are constrained by the lack of adequate equipment and trained operators. Since light microscopy delivers crucial methods for the diagnosis and screening of numerous diseases, several efforts have been made by the scientific community to develop low-cost devices such as 3D-printed portable microscopes. Nevertheless, these devices present some drawbacks that directly affect image quality: the capture of the samples is done via mobile phones; more affordable lenses are usually used, leading to poorer physical properties and images with lower depth of field; misalignments in the microscopic set-up regarding optical, mechanical, and illumination components are frequent, causing image distortions such as chromatic aberrations. This work investigates several pre-processing methods to tackle the presented issues and proposed a new workflow for low-cost microscopy. Additionally, two new deep learning models based on Convolutional Neural Networks are also proposed (EDoF-CNN-Fast and EDoF-CNN-Pairwise) to generate Extended Depth of Field (EDoF) images, and compared against state-of-the-art approaches. The models were tested using two different datasets of cytology microscopic images: public Cervix93 and a new dataset that has been made publicly available containing images captured with µSmartScope. Experimental results demonstrate that the proposed workflow can achieve state-of-the-art performance when generating EDoF images from low-cost microscopes. © 2022 The Author(s)

2023

Two-Stage Framework for Faster Semantic Segmentation

Autores
Cruz, R; Silva, DTE; Goncalves, T; Carneiro, D; Cardoso, JS;

Publicação
SENSORS

Abstract
Semantic segmentation consists of classifying each pixel according to a set of classes. Conventional models spend as much effort classifying easy-to-segment pixels as they do classifying hard-to-segment pixels. This is inefficient, especially when deploying to situations with computational constraints. In this work, we propose a framework wherein the model first produces a rough segmentation of the image, and then patches of the image estimated as hard to segment are refined. The framework is evaluated in four datasets (autonomous driving and biomedical), across four state-of-the-art architectures. Our method accelerates inference time by four, with additional gains for training time, at the cost of some output quality.