About project

In this project proposal, we plan to build novel multipurpose deep-learning systems, as descendants of advanced digital signal processing (DSP) methods. The novelty is based on their specific structure, which ensures desired directivity in the learning process. On the one hand, the idea is inspired by physics-informed neural networks (NNs). The laws of physics in such networks are incorporated in the cost criteria. The prior knowledge of general physical laws acts in the training of NNs as a regularization agent, limiting the space of admissible solutions and increasing the correctness of the objective function approximation. On the other hand, we found our inspiration in adaptive systems designed by the authors of this proposal more than a decade ago: the fixed part of such systems provides for retaining the desired properties, while the variable parameter part provides for adaptation. Remapping the same idea into the new field of deep learning will bring new and exciting results. The structure of such deep-learning networks will ensure that the solution remains in the frame of an acceptable mathematical solution or given limitations in physics, chemistry, or biology. For reference, we call it science-informed deep learning. 

 

Among others, one important application will be in the field of sampling (“new sampling paradigm”). Instead of function dictionaries, deep-learned networks that best fit the measurement will be used to model the reconstructed objects. Next, it will be used to create behavioral models of dynamic systems, which is an important element of autonomous systems. In different applications, it leads to solving ordinary or partial differential equations. Furthermore, the results of this project can be extended to almost any known application of DSP. It will open a completely new branch of intelligent processing systems.

 

Opposing traditional programming that was based on lists of precise human-authored instructions, the deep learning mantra is that everything can be learned from data: no instructions needed. Still, well-know instruction-based algorithms do the majority of data processing jobs, especially when the predictability of the results is crucial. Our life experience tells us that some things can be learned, but some must be given in advance to enable efficient learning. Many technical systems are inspired by nature. Deep learning systems and neural networks are not an exception. On the one hand, mammal brains consist of a large mass of general purpose neurons, in which damaged tissue can be replaced by the healthy one. It corresponds to the mentioned deep learning mantra: learning from data. On the other hand, specialized groups of neurons take care of hearing, image processing, keeping balance, even some logical operations. Moreover, control of life support functions, such as body temperature, heart beats or breathing rely on hard-wired and very specialized neuron groups.


In this project, we focused our efforts to embed the knowledge into the structure of the deep learning systems, rather than the cost criterion. It will bring predictability and interpretability of the results and speed up the learning process.

 

Preliminary results are available in the repository at the bottom of this page.
Here is a direct link to the preliminary results.

Team members

prof. dr. sc. Damir Seršić
project leader
full professor,  Department of Electronic Systems and Information Processing

e-mail: damir.sersic@fer.hr

prof. dr. sc. Davor Petrinović

full professor,  Department of Electronic Systems and Information Processing

e-mail: davor.petrinovic@fer.hr

izv. prof. dr. sc. Ana Sović Kržić

associate professor,  Department of Electronic Systems and Information Processing

e-mail: ana.sovic@fer.hr

izv. prof. dr. sc. Azra Tafro

associate professor,  University of Zagreb Faculty of Forestry

e-mail: azra.tafro@fer.hr

dr. sc. Ivan Ralašić

external associate,  CTO of Forsight

e-mail: ivan.ralasic@fer.hr

dr. sc. Tin Vlašić 

external associate, Postdoctoral Research Fellow at  A*STAR Singapore

e-mail: tin.vlasic@fer.hr

Tomislav Matulić, mag. ing.

assistant,  Department of Electronic Systems and Information Processing

e-mail: tomislav.matulic@fer.hr

Ivan Bukić, mag. ing. 

assistant,  Department of Electronic Systems and Information Processing

e-mail: ivan.bukic@fer.hr

 

Journal articles

T. Matulić and D. Seršić, "Stochastic model for enhanced PET image reconstruction", Biomedical Signal Processing and Control, vol. 94, no. 106294, 2024. doi: 10.1016/j.bspc.2024.106294
A. Tafro and D. Seršić, "Gaussian Mixture Estimation from Lower-Dimensional Data with Application to PET Imaging",  Mathematics, vol. 12 (5), no. 764, 2024. doi: 10.3390/math12050764
A. Gribl Koščević and D. Petrinović, "A Fast Method for Fitting a Multidimensional Gaussian Function," in IEEE Access, vol. 10, pp. 106921-106935, 2022. doi: 10.1109/ACCESS.2022.3212388
A. Tafro, D. Seršić and A. Sović Kržić, "2D PET Image Reconstruction Using Robust L1 Estimation of the Gaussian Mixture Model," Informatica, vol. 33, no. 3, pp. 653–6692022. doi: 10.15388/22-INFOR482
T. Vlašić and D. Seršić, "Single-pixel Compressive Imaging in Shift-Invariant Spaces via Exact Wavelet Frames," Signal Processing: Image Communication, vol. 105, article no. 116702, July 2022. doi: 10.1016/j.image.2022.116702
T. Vlašić and D. Seršić, "Sampling and Reconstruction of Sparse Signals in Shift-Invariant Spaces: Generalized Shannon's Theorem Meets Compressive Sensing," IEEE Transactions on Signal Processing, vol. 70, pp. 438-451, 2022. doi: 10.1109/TSP.2022.3141009
A. Gribl and D. Petrinović, "A Robust Method for Gaussian Profile Estimation in the Case of Overlapping Objects," IEEE Access, vol. 9, pp. 21071-21084, 2021. doi: 10.1109/ACCESS.2021.3055282

I. Ralašić, D. Seršić and S. Šegvić, "Perceptual Autoencoder for Compressive Sensing Image Reconstruction," Informatica, vol. 31, no. 3, pp. 561-578, 2020. doi: 10.15388/20-INFOR421

I. Ralašić, M. Đonlić and D. Seršić, "Dual Imaging–Can Virtual Be Better Than Real?," IEEE Access, vol. 8, pp. 40246-40260, 2020. doi: 10.1109/access.2020.2976870

N. Dlab, F. Cimermančić, I. Ralašić and D. Seršić, "Overcoming spatio-angular trade-off in light field acquisition using compressive sensing," Automatika, vol. 61, no. 2, pp. 250-259, 2020. doi: 10.1080/00051144.2020.1715582

T. Vlašić, I. Ralašić, A. Tafro and D. Seršić, "Spline-like Chebyshev polynomial model for compressive imaging," Journal of Visual Communication and Image Representation, vol. 66, article 102731, 2020. doi: 10.1016/j.jvcir.2019.102731

Conference papers

T. Vlašić, T. Matulić and D. Seršić, "Estimating Uncertainty in PET Image Reconstruction via Deep Posterior Sampling", Proceedings of Machine Learning Research, Medical Imaging with Deep Learning (MIDL2023), Nashville (TN), USA, 2023. link
D. Potoč and D. Petrinović, "Estimating a nonradial vignetting shape", 2023 46th MIPRO ICT and Electronics Convention (MIPRO), Opatija, Croatia, 2023. doi: 10.23919/MIPRO57284.2023.10159695
T. Vlašić, H. Nguyen, A. Khorashadizad and I. Dokmanić, "Implicit Neural Representation for Mesh-Free Inverse Obstacle Scattering", 2022 56th Asilomar Conference on Signals, Systems, and Computers, Pacific Grove (CA), USA, 2022. doi: 10.1109/IEEECONF56349.2022.10052055
A. Gribl Koščević and D. Petrinović, "Maximizing Accuracy of 2D Gaussian Profile Estimation Using Differential Entropy," 2022 45th Jubilee International Convention on Information, Communication and Electronic Technology (MIPRO), Opatija, Croatia, 2022, pp. 888-893, doi: 10.23919/MIPRO55190.2022.9803382
D. Potoč and D. Petrinović, "Creating a synthetic image for evaluation of vignetting modeling and estimation", 2022 45th Jubilee International Convention on Information, Communication and Electronic Technology (MIPRO), Opatija, Croatia, 2022, pp. 918-923, doi: 10.23919/MIPRO55190.2022.9803709
A. Gribl and D. Petrinović, "The Influence of Noise on 2D Gaussian Profile Parameters Estimation," 2021 44th International Convention on Information, Communication and Electronic Technology (MIPRO), Opatija, Croatia, 2021, pp. 1032-1037, doi: 10.23919/MIPRO52101.2021.9596661
T. Matulić, R. Bagarić and D. Seršić, "Enhanced reconstruction for PET scanner with a narrow field of view using backprojection method," 2021 44th International Convention on Information, Communication and Electronic Technology (MIPRO), Opatija, Croatia, 2021, pp. 317-322, doi: 10.23919/MIPRO52101.2021.9596922
T. Vlašić and D. Seršić, "Multilevel Subsampling of Principal Component Projections for Adaptive Compressive Sensing," 2021 12th International Symposium on Image and Signal Processing and Analysis (ISPA), Zagreb, Croatia, 2021, pp. 29-35, doi: 10.1109/ISPA52656.2021.9552127
A. Gribl Koščević and D. Petrinović, "Extra-low-dose 2D PET imaging," 2021 12th International Symposium on Image and Signal Processing and Analysis (ISPA), Zagreb, Croatia, 2021, pp. 84-90, doi: 10.1109/ISPA52656.2021.9552059

T. Vlašić and D. Seršić, "Sub-Nyquist Sampling in Shift-Invariant Spaces," 2020 28th European Signal Processing Conference (EUSIPCO), Amsterdam, Netherlands, 2021, pp. 2284-2288, doi: 10.23919/Eusipco47968.2020.9287712

I. Ralašić, M. Đonlić and D. Seršić, "High-Resolution View Synthesis In Camera-Projector Systems Using Compressive Dual Imaging," 2020 3rd International Conference on Sensors, Signal and Image Processing (SSIP), Prague, Czech Republic, 2020, pp. 7-12, doi: 10.1145/3441233.3441236

K. Sever, T. Vlašić and D. Seršić, "A Realization of Adaptive Compressive Sensing System," 2020 43rd International Convention on Information, Communication and Electronic Technology (MIPRO), Opatija, Croatia, 2020, pp. 152-157, doi: 10.23919/MIPRO48935.2020.9245389

A. Gribl and D. Petrinović, "Synthetic astronomical image sequence generation," 2020 43rd International Convention on Information, Communication and Electronic Technology (MIPRO), Opatija, Croatia, 2020, pp. 1103-1108, doi: 10.23919/MIPRO48935.2020.9245294

Other

A. Tafro, "Gaussian mixture model for PET image reconstruction with reduced sample size", 26th International Scientific Symposium on Biometrics (BIOSTAT2023), Zadar, Croatia, 2023.
T. Matulić and D. Seršić, "Probabilistic description of rotational 3D PET systems", 8th Int'l Workshop on Data Science (IWDS 2023), Zagreb, Croatia, 2023.
D. Potoč and D. Petrinović, "Estimation of non-radial vignetting using minimization procedures," Abstract Book of the 7th International Workshop on Data Science (IWDS), Zagreb, Croatia, pp. 17-19, 2022.
A. Gribl Koščević and D. Petrinović, "Fitting an elliptical paraboloid with the known shape to the empirical data",  7th International Workshop on Data Science (IWDS 2022), Zagreb, Croatia, 2022.
A. Gribl Koščević and D. Petrinović, "Fitting an elliptical paraboloid with the known shape to the empirical data," Abstract Book of the 7th International Workshop on Data Science (IWDS), Zagreb, Croatia, pp. 13-15, 2022.
T. Matulić, R. Bagarić and D. Seršić, "Fast reconstruction for PET scanner with incomplete sector set," Abstract Book of the 6th International Workshop on Data Science (IWDS), Zagreb, Croatia, pp. 19-21, 2021.

T. Vlašić and D. Seršić, "Statistical Compressive Sensing of Analog Signals in B-Spline Function Spaces," Abstract Book of the 5th International Workshop on Data Science (IWDS), Zagreb, Croatia, pp. 28-31, 2020.

A. Gribl and D. Petrinović, "The influence of the Huber estimator tuning constant on the performance of the iteratively reweighted least squares method," Abstract Book of the 5th International Workshop on Data Science (IWDS), Zagreb, Croatia, pp. 12-14, 2020.


Repository