Signal Processing

Acquisition and processing of information.

Our research in the area of signal processing encompasses a wide range of work in the areas of communications, sensing, estimation, localization, and speech and visual information processing. We explore novel approaches for signal acquisition and coding, methods to filter and recover signals in the presence of noise and other degrading factors, and techniques that infer meaning from the processed signals.

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  • Researchers

  • Awards

    •  AWARD    Best paper award at PHMAP 2023
      Date: September 14, 2023
      Awarded to: Dehong Liu, Anantaram Varatharajan, and Abraham Goldsmith
      MERL Contacts: Abraham Goldsmith; Dehong Liu
      Research Areas: Electric Systems, Signal Processing
      Brief
      • MERL researchers Dehong Liu, Anantaram Varatharajan, and Abraham Goldsmith were awarded one of three best paper awards at Asia Pacific Conference of the Prognostics and Health Management Society 2023 (PHMAP23) held in Tokyo from September 11th to 14th, 2023, for their co-authored paper titled 'Extracting Broken-Rotor-Bar Fault Signature of Varying-Speed Induction Motors.'

        PHMAP is a biennial international conference specialized in prognostics and health management. PHMAP23 attracted more than 300 attendees from worldwide and published more than 160 regular papers from academia and industry including aerospace, production, civil engineering, electronics, and so on.
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    •  AWARD    MERL’s Paper on Wi-Fi Sensing Earns Top 3% Paper Recognition at ICASSP 2023, Selected as a Best Student Paper Award Finalist
      Date: June 9, 2023
      Awarded to: Cristian J. Vaca-Rubio, Pu Wang, Toshiaki Koike-Akino, Ye Wang, Petros Boufounos and Petar Popovski
      MERL Contacts: Petros T. Boufounos; Toshiaki Koike-Akino; Pu (Perry) Wang; Ye Wang
      Research Areas: Artificial Intelligence, Communications, Computational Sensing, Dynamical Systems, Machine Learning, Signal Processing
      Brief
      • A MERL Paper on Wi-Fi sensing was recognized as a Top 3% Paper among all 2709 accepted papers at the 2023 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2023). Co-authored by Cristian Vaca-Rubio and Petar Popovski from Aalborg University, Denmark, and MERL researchers Pu Wang, Toshiaki Koike-Akino, Ye Wang, and Petros Boufounos, the paper "MmWave Wi-Fi Trajectory Estimation with Continous-Time Neural Dynamic Learning" was also a Best Student Paper Award finalist.

        Performed during Cristian’s stay at MERL first as a visiting Marie Skłodowska-Curie Fellow and then as a full-time intern in 2022, this work capitalizes on standards-compliant Wi-Fi signals to perform indoor localization and sensing. The paper uses a neural dynamic learning framework to address technical issues such as low sampling rate and irregular sampling intervals.

        ICASSP, a flagship conference of the IEEE Signal Processing Society (SPS), was hosted on the Greek island of Rhodes from June 04 to June 10, 2023. ICASSP 2023 marked the largest ICASSP in history, boasting over 4000 participants and 6128 submitted papers, out of which 2709 were accepted.
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    •  AWARD    Best Paper Award of 2022 IPSJ Transactions on Consumer Devices & Systems
      Date: March 27, 2023
      Awarded to: Yukimasa Nagai, Takenori Sumi, Jianlin Guo, Philip Orlik, Hiroshi Mineno
      MERL Contacts: Jianlin Guo; Philip V. Orlik; Kieran Parsons
      Research Areas: Communications, Signal Processing
      Brief
      • MELCO/MERL research paper “IEEE 802.19.3 Standardization for Coexistence of IEEE 802.11ah and IEEE 802.15.4g Systems in Sub-1GHz Frequency Bands” has won the Best Paper Award of the 2022 IPSJ Transactions on Consumer Devices and Systems. The Information Processing Society of Japan (IPSJ) award was established in 1970 and is conferred on the authors of particularly excellent papers, which are published in the IPSJ journals and transactions. Our paper was published by the IPSJ Transaction on Consumer Device and System Vol. 29 in 2021 and authors are Yukimasa Nagai, Takenori Sumi, Jianlin Guo, Philip Orlik and Hiroshi Mineno.
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  • News & Events

    •  TALK    [MERL Seminar Series 2025] David Lindell presents talk titled Imaging Dynamic Scenes from Seconds to Picoseconds
      Date & Time: Wednesday, January 29, 2025; 1:00 PM
      Speaker: David Lindell, University of Toronto
      MERL Host: Joshua Rapp
      Research Areas: Computational Sensing, Computer Vision, Signal Processing
      Abstract
      • The observed timescales of the universe span from the exasecond scale (~1e18 seconds) down to the zeptosecond scale (~1e-21 seconds). While specialized imaging systems can capture narrow slices of this temporal spectrum in the ultra-fast regime (e.g., nanoseconds to picoseconds; 1e-9 to 1e-12 s), they cannot simultaneously capture both slow (> 1 second) and ultra-fast events (< 1 nanosecond). Further, ultra-fast imaging systems are conventionally limited to single-viewpoint capture, hindering 3D visualization at ultra-fast timescales. In this talk, I discuss (1) new computational algorithms that turn a single-photon detector into an "ultra-wideband" imaging system that captures events from seconds to picoseconds; and (2) a method for neural rendering using multi-viewpoint, ultra-fast videos captured using single-photon detectors. The latter approach enables rendering videos of propagating light from novel viewpoints, observation of viewpoint-dependent changes in light transport predicted by Einstein, recovery of material properties, and accurate 3D reconstruction from multiply scattered light. Finally, I discuss future directions in ultra-wideband imaging.
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    •  NEWS    MERL Researchers to Present 2 Conference and 11 Workshop Papers at NeurIPS 2024
      Date: December 10, 2024 - December 15, 2024
      Where: Advances in Neural Processing Systems (NeurIPS)
      MERL Contacts: Petros T. Boufounos; Matthew Brand; Ankush Chakrabarty; Anoop Cherian; François Germain; Toshiaki Koike-Akino; Christopher R. Laughman; Jonathan Le Roux; Jing Liu; Suhas Lohit; Tim K. Marks; Yoshiki Masuyama; Kieran Parsons; Kuan-Chuan Peng; Diego Romeres; Pu (Perry) Wang; Ye Wang; Gordon Wichern
      Research Areas: Artificial Intelligence, Communications, Computational Sensing, Computer Vision, Control, Data Analytics, Dynamical Systems, Machine Learning, Multi-Physical Modeling, Optimization, Robotics, Signal Processing, Speech & Audio, Human-Computer Interaction, Information Security
      Brief
      • MERL researchers will attend and present the following papers at the 2024 Advances in Neural Processing Systems (NeurIPS) Conference and Workshops.

        1. "RETR: Multi-View Radar Detection Transformer for Indoor Perception" by Ryoma Yataka (Mitsubishi Electric), Adriano Cardace (Bologna University), Perry Wang (Mitsubishi Electric Research Laboratories), Petros Boufounos (Mitsubishi Electric Research Laboratories), Ryuhei Takahashi (Mitsubishi Electric). Main Conference. https://neurips.cc/virtual/2024/poster/95530

        2. "Evaluating Large Vision-and-Language Models on Children's Mathematical Olympiads" by Anoop Cherian (Mitsubishi Electric Research Laboratories), Kuan-Chuan Peng (Mitsubishi Electric Research Laboratories), Suhas Lohit (Mitsubishi Electric Research Laboratories), Joanna Matthiesen (Math Kangaroo USA), Kevin Smith (Massachusetts Institute of Technology), Josh Tenenbaum (Massachusetts Institute of Technology). Main Conference, Datasets and Benchmarks track. https://neurips.cc/virtual/2024/poster/97639

        3. "Probabilistic Forecasting for Building Energy Systems: Are Time-Series Foundation Models The Answer?" by Young-Jin Park (Massachusetts Institute of Technology), Jing Liu (Mitsubishi Electric Research Laboratories), François G Germain (Mitsubishi Electric Research Laboratories), Ye Wang (Mitsubishi Electric Research Laboratories), Toshiaki Koike-Akino (Mitsubishi Electric Research Laboratories), Gordon Wichern (Mitsubishi Electric Research Laboratories), Navid Azizan (Massachusetts Institute of Technology), Christopher R. Laughman (Mitsubishi Electric Research Laboratories), Ankush Chakrabarty (Mitsubishi Electric Research Laboratories). Time Series in the Age of Large Models Workshop.

        4. "Forget to Flourish: Leveraging Model-Unlearning on Pretrained Language Models for Privacy Leakage" by Md Rafi Ur Rashid (Penn State University), Jing Liu (Mitsubishi Electric Research Laboratories), Toshiaki Koike-Akino (Mitsubishi Electric Research Laboratories), Shagufta Mehnaz (Penn State University), Ye Wang (Mitsubishi Electric Research Laboratories). Workshop on Red Teaming GenAI: What Can We Learn from Adversaries?

        5. "Spatially-Aware Losses for Enhanced Neural Acoustic Fields" by Christopher Ick (New York University), Gordon Wichern (Mitsubishi Electric Research Laboratories), Yoshiki Masuyama (Mitsubishi Electric Research Laboratories), François G Germain (Mitsubishi Electric Research Laboratories), Jonathan Le Roux (Mitsubishi Electric Research Laboratories). Audio Imagination Workshop.

        6. "FV-NeRV: Neural Compression for Free Viewpoint Videos" by Sorachi Kato (Osaka University), Takuya Fujihashi (Osaka University), Toshiaki Koike-Akino (Mitsubishi Electric Research Laboratories), Takashi Watanabe (Osaka University). Machine Learning and Compression Workshop.

        7. "GPT Sonography: Hand Gesture Decoding from Forearm Ultrasound Images via VLM" by Keshav Bimbraw (Worcester Polytechnic Institute), Ye Wang (Mitsubishi Electric Research Laboratories), Jing Liu (Mitsubishi Electric Research Laboratories), Toshiaki Koike-Akino (Mitsubishi Electric Research Laboratories). AIM-FM: Advancements In Medical Foundation Models: Explainability, Robustness, Security, and Beyond Workshop.

        8. "Smoothed Embeddings for Robust Language Models" by Hase Ryo (Mitsubishi Electric), Md Rafi Ur Rashid (Penn State University), Ashley Lewis (Ohio State University), Jing Liu (Mitsubishi Electric Research Laboratories), Toshiaki Koike-Akino (Mitsubishi Electric Research Laboratories), Kieran Parsons (Mitsubishi Electric Research Laboratories), Ye Wang (Mitsubishi Electric Research Laboratories). Safe Generative AI Workshop.

        9. "Slaying the HyDRA: Parameter-Efficient Hyper Networks with Low-Displacement Rank Adaptation" by Xiangyu Chen (University of Kansas), Ye Wang (Mitsubishi Electric Research Laboratories), Matthew Brand (Mitsubishi Electric Research Laboratories), Pu Wang (Mitsubishi Electric Research Laboratories), Jing Liu (Mitsubishi Electric Research Laboratories), Toshiaki Koike-Akino (Mitsubishi Electric Research Laboratories). Workshop on Adaptive Foundation Models.

        10. "Preference-based Multi-Objective Bayesian Optimization with Gradients" by Joshua Hang Sai Ip (University of California Berkeley), Ankush Chakrabarty (Mitsubishi Electric Research Laboratories), Ali Mesbah (University of California Berkeley), Diego Romeres (Mitsubishi Electric Research Laboratories). Workshop on Bayesian Decision-Making and Uncertainty. Lightning talk spotlight.

        11. "TR-BEACON: Shedding Light on Efficient Behavior Discovery in High-Dimensions with Trust-Region-based Bayesian Novelty Search" by Wei-Ting Tang (Ohio State University), Ankush Chakrabarty (Mitsubishi Electric Research Laboratories), Joel A. Paulson (Ohio State University). Workshop on Bayesian Decision-Making and Uncertainty.

        12. "MEL-PETs Joint-Context Attack for the NeurIPS 2024 LLM Privacy Challenge Red Team Track" by Ye Wang (Mitsubishi Electric Research Laboratories), Tsunato Nakai (Mitsubishi Electric), Jing Liu (Mitsubishi Electric Research Laboratories), Toshiaki Koike-Akino (Mitsubishi Electric Research Laboratories), Kento Oonishi (Mitsubishi Electric), Takuya Higashi (Mitsubishi Electric). LLM Privacy Challenge. Special Award for Practical Attack.

        13. "MEL-PETs Defense for the NeurIPS 2024 LLM Privacy Challenge Blue Team Track" by Jing Liu (Mitsubishi Electric Research Laboratories), Ye Wang (Mitsubishi Electric Research Laboratories), Toshiaki Koike-Akino (Mitsubishi Electric Research Laboratories), Tsunato Nakai (Mitsubishi Electric), Kento Oonishi (Mitsubishi Electric), Takuya Higashi (Mitsubishi Electric). LLM Privacy Challenge. Won 3rd Place Award.

        MERL members also contributed to the organization of the Multimodal Algorithmic Reasoning (MAR) Workshop (https://marworkshop.github.io/neurips24/). Organizers: Anoop Cherian (Mitsubishi Electric Research Laboratories), Kuan-Chuan Peng (Mitsubishi Electric Research Laboratories), Suhas Lohit (Mitsubishi Electric Research Laboratories), Honglu Zhou (Salesforce Research), Kevin Smith (Massachusetts Institute of Technology), Tim K. Marks (Mitsubishi Electric Research Laboratories), Juan Carlos Niebles (Salesforce AI Research), Petar Veličković (Google DeepMind).
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  • Research Highlights

  • Internships

    • CI0082: Internship - Quantum AI

      MERL is excited to announce an internship opportunity in the field of Quantum Machine Learning (QML) and Quantum AI (QAI). We are seeking a highly motivated and talented individual to join our research team. This is an exciting opportunity to make a real impact in the field of quantum computing and AI, with the aim of publishing at leading research venues.

      Responsibilities:

      • Conduct cutting-edge research in quantum machine learning.
      • Collaborate with a team of experts in quantum computing, deep learning, and signal processing.
      • Develop and implement algorithms using PyTorch and PennyLane.
      • Publish research results at leading research venues.

      Qualifications:

      • Currently pursuing a PhD or a post-graduate researcher in a relevant field.
      • Strong background and solid publication records in quantum computing, deep learning, and signal processing.
      • Proficient programming skills in PyTorch and PennyLane are highly desirable.

      What We Offer:

      • An opportunity to work on groundbreaking research in a leading research lab.
      • Collaboration with a team of experienced researchers.
      • A stimulating and supportive work environment.

      If you are passionate about quantum machine learning and meet the above qualifications, we encourage you to apply. Please submit your resume and a brief cover letter detailing your research experience and interests. Join us at MERL and contribute to the future of quantum machine learning!

    • EA0069: Internship - PWM inverter switching loss reduction

      MERL is looking for a self-motivated intern to work on PWM inverter simulation and design. The ideal candidate would be a Ph.D. candidate in electrical engineering with solid research background in power electronics, control, and optimization. Experience in switching loss reduction modulation is desired. The intern is expected to collaborate with MERL researchers to carry out simulations, optimize design, analyze results, and prepare manuscripts for scientific publications. The total duration is 3 months.

      Required Specific Experience

      • Experience with simulation tools for PWM inverter design.

    • ST0116: Internship - Deep Learning for Radar Perception

      The Computation Sensing team at MERL is seeking a highly motivated intern to conduct fundamental research in radar perception. Expertise in deep learning-based object detection, pose estimation, segmentation, multiple object tracking (MOT), and representation learning on radar data is required. Previous hands-on experience with open indoor and outdoor radar datasets is a plus. Familiarity with basic radar concepts and MERL's recent work in radar perception is an asset. The intern will work closely with MERL researchers to develop novel algorithms, design experiments with MERL in-house testbed, and prepare results for patents and publication. The internship is expected to last 3 months with a preferred start date after June 2025.

      Required Specific Experience

      • Solid understanding of state-of-the-art perception frameworks including transformer-based (e.g., DETR) and diffusion-based (e.g., DiffusionDet) methods.
      • Hands-on experience with open large-scale radar datasets such as MMVR, HIBER, RADIATE, and K-Radar.
      • Proficiency in Python and experience with job scheduling on GPU clusters using tools like Slurm.
      • Proven publication records in top-tier venues such as CVPR, ICCV, ECCV, NeurIPS.
      • Knowledge of basic radar concepts such as FMCW, MIMO, (micro-) Doppler signature, radar point clouds, heatmaps, and raw ADC waveforms.
      • Familiarity with MERL's recent radar perception research such as TempoRadar, SIRA, MMVR, and RETR.


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  • Openings


    See All Openings at MERL

  • Recent Publications

    •  Kitichotkul, R., Rapp, J., Ma, Y., Mansour, H., "Doppler Single-Photon Lidar", IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), March 2025.
      BibTeX TR2025-028 PDF
      • @inproceedings{Kitichotkul2025mar,
      • author = {Kitichotkul, Ruangrawee and Rapp, Joshua and Ma, Yanting and Mansour, Hassan},
      • title = {{Doppler Single-Photon Lidar}},
      • booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)},
      • year = 2025,
      • month = mar,
      • url = {https://www.merl.com/publications/TR2025-028}
      • }
    •  Teh, A., Ali, W.H., Rapp, J., Mansour, H., "Indoor Airflow Imaging Using Physics-Informed Schlieren Tomography", IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), March 2025.
      BibTeX TR2025-035 PDF
      • @inproceedings{Teh2025mar,
      • author = {Teh, Arjun and Ali, Wael H. and Rapp, Joshua and Mansour, Hassan},
      • title = {{Indoor Airflow Imaging Using Physics-Informed Schlieren Tomography}},
      • booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)},
      • year = 2025,
      • month = mar,
      • url = {https://www.merl.com/publications/TR2025-035}
      • }
    •  Attiah, K., Wang, P., Mansour, H., Koike-Akino, T., Boufounos, P.T., "Enabling DMG Wi-Fi Sensing in Data Transmission Intervals by Exploiting Beam Training Codebook", IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), March 2025.
      BibTeX TR2025-026 PDF
      • @inproceedings{Attiah2025mar,
      • author = {Attiah, Kareem and Wang, Pu and Mansour, Hassan and Koike-Akino, Toshiaki and Boufounos, Petros T.},
      • title = {{Enabling DMG Wi-Fi Sensing in Data Transmission Intervals by Exploiting Beam Training Codebook}},
      • booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)},
      • year = 2025,
      • month = mar,
      • url = {https://www.merl.com/publications/TR2025-026}
      • }
    •  Yataka, R., Wang, P., Boufounos, P.T., Takahashi, R., "Multi-View Radar Detection Transformer with Differentiable Positional Encoding", IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), March 2025.
      BibTeX TR2025-027 PDF
      • @inproceedings{Yataka2025mar,
      • author = {Yataka, Ryoma and Wang, Pu and Boufounos, Petros T. and Takahashi, Ryuhei},
      • title = {{Multi-View Radar Detection Transformer with Differentiable Positional Encoding}},
      • booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)},
      • year = 2025,
      • month = mar,
      • url = {https://www.merl.com/publications/TR2025-027}
      • }
    •  Greiff, M., Di Cairano, S., Berntorp, K., "Bayesian Measurement Masks for GNSS Positioning", IEEE Conference on Decision and Control (CDC), December 2024.
      BibTeX TR2024-172 PDF
      • @inproceedings{Greiff2024dec,
      • author = {Greiff, Marcus and {Di Cairano}, Stefano and Berntorp, Karl},
      • title = {{Bayesian Measurement Masks for GNSS Positioning}},
      • booktitle = {IEEE Conference on Decision and Control (CDC)},
      • year = 2024,
      • month = dec,
      • url = {https://www.merl.com/publications/TR2024-172}
      • }
    •  Ozcan, E.C., Giammarino, V., Queeney, J., Paschalidis, I.C., "A Model-Based Approach for Improving Reinforcement Learning Efficiency Leveraging Expert Observations", IEEE Conference on Decision and Control (CDC), December 2024.
      BibTeX TR2024-178 PDF
      • @inproceedings{Ozcan2024dec,
      • author = {Ozcan, Erhan Can and Giammarino, Vittorio and Queeney, James and Paschalidis, Ioannis Ch.},
      • title = {{A Model-Based Approach for Improving Reinforcement Learning Efficiency Leveraging Expert Observations}},
      • booktitle = {IEEE Conference on Decision and Control (CDC)},
      • year = 2024,
      • month = dec,
      • url = {https://www.merl.com/publications/TR2024-178}
      • }
    •  Greiff, M., Berntorp, K., "Asynchronous Variational-Bayes Kalman Filtering", IEEE Conference on Decision and Control (CDC), December 2024.
      BibTeX TR2024-177 PDF
      • @inproceedings{Greiff2024dec2,
      • author = {Greiff, Marcus and Berntorp, Karl},
      • title = {{Asynchronous Variational-Bayes Kalman Filtering}},
      • booktitle = {IEEE Conference on Decision and Control (CDC)},
      • year = 2024,
      • month = dec,
      • url = {https://www.merl.com/publications/TR2024-177}
      • }
    •  Rapp, J., Mansour, H., Boufounos, P.T., Koike-Akino, T., Parsons, K., "ulti-layered Surface Estimation for Low-cost Optical Coherence Tomography", IEEE Transactions on Computational Imaging, DOI: 10.1109/​TCI.2024.3497602, Vol. 10, pp. 1706-1721, December 2024.
      BibTeX TR2024-164 PDF
      • @article{Rapp2024dec,
      • author = {Rapp, Joshua and Mansour, Hassan and Boufounos, Petros T. and Koike-Akino, Toshiaki and Parsons, Kieran},
      • title = {{ulti-layered Surface Estimation for Low-cost Optical Coherence Tomography}},
      • journal = {IEEE Transactions on Computational Imaging},
      • year = 2024,
      • volume = 10,
      • pages = {1706--1721},
      • month = dec,
      • doi = {10.1109/TCI.2024.3497602},
      • url = {https://www.merl.com/publications/TR2024-164}
      • }
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