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Jurica Maltar

 

PhD student
Department of Mathematics
Josip Juraj Strossmayer University of Osijek
Trg Ljudevita Gaja 6
Osijek, HR-31000, Croatia
phone: +385-31-224-805
email:  This email address is being protected from spambots. You need JavaScript enabled to view it.
office:  5 (ground floor)

 Google Scholar


Research Interests

Computer Vision
Deep Learning
Robotics

Degrees

MSc in mathematics, Mathematics and Computer Science, Department of Mathematics, University of Osijek, Croatia, 2017.
BSc in Mathematics, Department of Mathematics, University of Osijek, Croatia, 2015.
 

Publications

 
Journal Publications

  1. J. Maltar, I. Marković, I. Petrović, Visual Place Recognition using Directed Acyclic Graph Association Measures and Mutual Information-based Feature Selection, Robotics and Autonomous Systems 132 (2020)
    Visual localization is a challenging problem, especially over the long run, since places can exhibit significant variation due to dynamic environmental and seasonal changes. To tackle this problem, we propose a visual place recognition method based on directed acyclic graph matching and feature maps extracted from deep convolutional neural networks (DCNN). Furthermore, in order to find the best subset of DCNN feature maps with minimal redundancy, we propose to form probability distributions on image representation features and leverage the Jensen-Shannon divergence to rank features. We evaluate the proposed approach on two challenging public datasets, namely the Bonn and the Freiburg datasets, and compare it to the state-of-the-art methods. For image representations, we evaluated the following DCNN architectures: AlexNet, OverFeat, ResNet18 and ResNet50. Due to the proposed graph structure, we are able to account for any kind of correlations in image sequences, and therefore dub our approach NOSeqSLAM. Algorithms with and without feature selection were evaluated based on precision-recall curves, area under the curve score, best recall at 100% precision score and running time, with NOSeqSLAM outperforming the counterpart approaches. Furthermore, by formulating the mutual information-based feature selection specifically for visual place recognition and by selecting the feature percentile with the best score, all the algorithms, and not just NOSeqSLAM, exhibited enhanced performance with the reduced feature set.


Refereed Proceedings

  1. J. Maltar, I. Marković, I. Petrović, NOSeqSLAM: Not only Sequential SLAM, Robot 2019: Fourth Iberian Robotics Conference, Porto, Portugal, 2019, 179-190
    The essential property that every autonomous system should have is the ability to localize itself, i.e., to reason about its location relative to measured landmarks and leverage this information to consistently estimate vehicle location through time. One approach to solving the localization problem is visual place recognition. Using only camera images, this approach has the following goal: during the second traversal through the environment, using only current images, find the match in the database that was created during a previously driven traversal of the same route. Besides the image representation method – in this paper we use feature maps extracted from the OverFeat architecture – for visual place recognition it is also paramount to perform the scene matching in a proper way. For autonomous vehicles and robots traversing through an environment, images are acquired sequentially, thus visual place recognition localization approaches use the structure of sequentiality to locally match image sequences to the database for higher accuracy. In this paper we propose a not only sequential approach to localization; specifically, instead of linearly searching for sequences, we construct a directed acyclic graph and search for any kind of sequences. We evaluated the proposed approach on a dataset consisting of varying environmental conditions and demonstrated that it outperforms the SeqSLAM approach.



 

Teaching

Konzultacije (Office Hours):  Konzultacije po dogovoru.

Nastavne aktivnosti u zimskom semestru akademske 2021./2022.

Nastavne aktivnosti u ljetnom semestru akademske 2021./2022.


Personal

  • Birthdate: 01. 04. 1993.
  • Birthplace: Osijek