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Welcome New MCL Member Claire Wang

We are very happy to welcome a new MCL member, Claire Wang. Here is a quick interview with Claire:

1. Could you briefly introduce yourself and your research interests?My name is Claire Wang, and I am currently a Ph.D. student in Electrical Engineering at USC. I received my bachelor’s degree from National Taiwan University (NTU). My research interests include machine learning and image processing, especially their applications in interdisciplinary problems. Outside of academics, I enjoy traveling, reading, singing and photography.

2. What is your impression of MCL and USC?My impression of MCL lab is that it provides a highly collaborative, strong and warm community where students are encouraged to explore research ideas under the guidance of experienced mentors. USC feels very dynamic and diverse, offering not only strong academic resources but also opportunities to connect with people from different cultural and professional backgrounds.

3. What is your future expectation and plan in MCL?

In MCL, I hope to build strong interactions with lab members, exchange ideas and collaborate on projects. I also look forward to learning from both Professor Kuo and my peers, not only to strengthen my research abilities but also to broaden my perspectives. I would like to gain a deeper understanding of Green Learning, explore its applications, and steadily contribute to the lab’s progress.

By |September 28th, 2025|News|Comments Off on Welcome New MCL Member Claire Wang|
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    Wei Wang, Jie-En Yao, Xinyu Wang, Haiyi Li, Vasileios Magoulianitis Attended ICIP 2025

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Wei Wang, Jie-En Yao, Xinyu Wang, Haiyi Li, Vasileios Magoulianitis Attended ICIP 2025

The IEEE International Conference on Image Processing (ICIP 2025), “Imaging in the Age of GenAI”, took place from September 14 to 18, 2025, in Anchorage, Alaska, USA. ICIP this year features a robust program of keynote lectures, oral and poster presentations, and workshops covering the latest breakthroughs in signal and image processing. It places a strong focus on machine learning and its subfields as a core driving force in image and video processing. Biomedical imaging continues to be a major area of interest. The conference is interested in traditional medical imaging and medical image analysis, but also in emerging biological image analysis and biomedical signal processing methods. Another major thematic area is computational imaging and related hardware-algorithm co-design. Topics include sparse, low-rank, and low-dimensional modeling; optimization-based inverse problem methods; sensor fusion; novel acquisition modalities. There is also interest in methods that quantify uncertainty and performance in computational imaging. Image and video techniques of representation, processing, analysis, and retrieval are also broadly covered.

MCL members presented four works in ICIP 2025, including “MA-YOLO: Video Object Detection via Motion-assisted YOLO” (by Xinyu Wang), “A Green Learning Approach to LDCT Image Restoration” (by Wei Wang), “MXB: Multi-stage XGboost for Efficient Tree-based Gradient Boosting” (by Haiyi Li), “SHFE: Transparent and Green Image Classification via Supervised Hierarchical Feature Extraction” (by Jie-En Yao). The works we proposed involves the fundamental learning module study as well as approaches following the Green Learning scheme to important applications in image and video processing. The principle of our proposed methods mainly lies in mathematical transparency, competitive performance, and outstanding efficiency in space and time complexity.

In addition to pioneering academic presentations, ICIP also offered professional development and networking opportunities, such as technical tutorials, industry workshops, student [...]

By |September 21st, 2025|News|Comments Off on Wei Wang, Jie-En Yao, Xinyu Wang, Haiyi Li, Vasileios Magoulianitis Attended ICIP 2025|
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    Congratulations to Aolin Feng for Passing His Qualifying Exam

Congratulations to Aolin Feng for Passing His Qualifying Exam

Congratulations to Aolin Feng for passing his Qualifying Exam! His thesis proposal is titled “ Green Image Coding: Principle, Implementation, and Performance Evaluation.” His Qualifying Exam Committee members include Jay Kuo (Chair), Antonio Ortega, Bhaskar Krishnamachari, Feng Qian, and Shanghao Teng (Outside Member). Here is a summary of his thesis proposal:

Image compression has long been dominated by two paradigms: the hybrid coding framework that adopts prediction and transform followed by scalar quantization, and deep learning-based codecs that leverage end-to-end optimization. While hybrid codecs offer reliable rate–distortion (RD) performance, they face a bottleneck for RD gain when integrating additional coding tools. In contrast, deep learning-based codecs achieve superior RD performance through end-to-end optimization but often suffer from high computational cost, especially for the decoder side.

The thesis proposal introduces Green Image Coding (GIC), a novel framework aiming for lightweight, RD-efficient, and scalable image compression. Different from the hybrid and deep learning-based coding, GIC is built upon two key designs: multigrid representation and vector quantization (VQ). The multigrid representation decomposes images into hierarchical layers, redistributing energy and reducing intra-layer content diversity. Each layer is then encoded using VQ-based techniques. 

Regarding the two key designs, we contribute both theoretical foundations and practical solutions: multigrid rate control and a set of advanced VQ techniques. For the multigrid rate control, we develop a theory that reduces a high-dimensional optimization to equivalent sequential parameter decisions, with comprehensive experimental validation. The theoretical conclusion guides the design of our rate control strategy, which improves the scalability and balance between rate and distortion. For the advanced VQ techniques, we start with tree-structured vector quantization (TSVQ) to build multi-rate coding capability, and propose an RD-oriented VQ codebook construction method. We also propose the cascade VQ strategy to tackle the [...]

By |September 14th, 2025|News|Comments Off on Congratulations to Aolin Feng for Passing His Qualifying Exam|

Congratulations to Mahtab Movahhedrad for Passing Her Qualifying Exam

Congratulations to Mahtab Movahhedrad for passing her qualifying exam! Her thesis proposal is titled “Explainable Machine Learning for Efficient Image Processing and Enhancement.” Her Qualifying Exam Committee members include Jay Kuo (Chair), Antonio Ortega, Bhaskar Krishnamachari, Justin Haldar, and Mejsam Razaviyayn (Outside Member). Here is a summary of her thesis proposal:

Image Signal Processors (ISPs) are critical components of modern imaging systems, responsible for transforming raw sensor data into high-quality images through a series of processing stages. Key operations such as demosaicking and dehazing directly influence color fidelity, detail preservation, and visual clarity. While traditional methods rely on handcrafted models, deep learning has recently shown strong performance in these tasks, albeit at the expense of computational efficiency and energy consumption.

With the increasing demand for mobile photography, balancing image quality with resource efficiency has become essential, particularly for battery-powered devices. This work addresses the challenge by leveraging the principles of green learning (GL), which emphasizes compact model architectures and reduced complexity. The GL framework operates in three cascaded stages—unsupervised representation learning, semi-supervised feature learning, and supervised decision learning—allowing efficient, interpretable, and reusable solutions.

Building on this foundation, my work introduces three methods: Green Image Demosaicking (GID), Green U-Shaped Image Demosaicking (GUSID), and Green U-Shaped Learning Dehazing (GUSL-Dehaze). GID offers a modular, lightweight alternative to conventional deep neural networks, achieving competitive accuracy with minimal resource usage. GUSID extends this efficiency with a U-shaped encoder–decoder design that enhances reconstruction quality while further reducing complexity. Finally, GUSL-Dehaze combines physics-based modeling with green learning principles to restore contrast and natural colors in hazy conditions, rivaling deep learning approaches at a fraction of the cost.

Together, these contributions advance ISP design by delivering high-quality, interpretable, and energy-efficient imaging solutions suitable for mobile and embedded platforms.

By |September 7th, 2025|News|Comments Off on Congratulations to Mahtab Movahhedrad for Passing Her Qualifying Exam|

MCL Research on Green IR Drop Prediction

This work introduces Green IR Drop (GIRD), an energy-efficient and high-performance static IR-drop estimation method built on green learning principles. GIRD processes IC design inputs in three stages. First, the circuit netlist is transformed into multichannel maps, from which joint spatial–spectral representations are extracted using PixelHop. Next, discriminant features are identified through the Relevant Feature Test (RFT). Finally, these selected features are passed to an eXtreme Gradient Boosting (XGBoost) regressor. Both PixelHop and RFT belong to the family of green learning tools. Thanks to their lightweight design, GIRD achieves a low carbon footprint with significantly smaller model sizes and reduced computational complexity. Moreover, GIRD maintains strong performance even with limited training data. Experimental results on both synthetic and real-world circuits confirm its superior effectiveness. In terms of efficiency, GIRD’s model size and floating-point operation count (FLOPs) are only about 10⁻³ and 10⁻² of those required by deep learning methods, respectively.

By |August 24th, 2025|News|Comments Off on MCL Research on Green IR Drop Prediction|

Attendance at MIPR 2025 – San Jose

The 2025 IEEE Conference on Multimedia Information Processing and Retrieval (MIPR) was held in San Jose from August 6 to 8. The event commenced with three keynote addresses: Prof. Prem Devanbu (University of California, Davis) discussed the reliability of large language models for code generation and offered guidance on when their results can be trusted. Prof. Edward Y. Chang (Stanford University) presented adaptive multi-modal learning as a way to address LLM limitations. Dr. Ed H. Chi (Google DeepMind) spoke on the future of AI-assisted discovery, highlighting systems that enhance rather than replace human expertise.During the conference, Mahtab Movhhedrad, a member of the Media Communications Lab (MCL), presented the paper “GUSL-Dehaze: A Green U-Shaped Learning Approach to Image Dehazing.” This work introduced GUSL-Dehaze, a physics-based green learning framework for image dehazing that completely avoids deep neural networks. The method begins with a modified Dark Channel Prior for initial dehazing, followed by a U-shaped architecture enabling unsupervised representation learning. Feature-engineering techniques such as Relevant Feature Test (RFT) and Least-Squares Normal Transform (LNT) were employed to keep the model compact and interpretable. The final dehazed image is produced through a transparent supervised learning stage, allowing the method to achieve performance comparable to deep learning approaches while maintaining a low parameter count and mathematical transparency.The conference also included a panel session, “Learning Beyond Deep Learning (LB-DL) for Multimedia Processing,” chaired by Prof. Ling Guan (Toronto Metropolitan University/Ryerson University) and Prof. C.-C. Jay Kuo (University of Southern California, Director of the MCL Lab). Prof. Kuo discussed emerging paradigms that challenge the dominance of deep learning, emphasizing the growing importance of interpretability, efficiency, and sustainability in shaping the next generation of multimedia research.

By |August 17th, 2025|News|Comments Off on Attendance at MIPR 2025 – San Jose|

MCL Research on Eosinophilic esophagitis (EoE) Diagnosis

Eosinophils are a type of white blood cell that can both protect the body and cause disease. While they are essential for fighting certain parasitic infections, they are also a primary cause of many allergic conditions when they don’t function correctly. It’s important to understand these cells because their buildup and activation are the main reasons for tissue damage in diseases like asthma and Eosinophilic Esophagitis (EoE).

Our current work explores the use of a dictionary learning pipeline to get unsupervised representations of whole-slide images of EoE. Unlike deep learning methods that require back-propagation to optimize millions of parameters to get data representations, our method represents the data in a self-organized way, with no back-propagation at all.

Compared to many other machine learning methods, our new pipeline provides a more transparent and explainable approach, especially for medical image analysis with smaller, specialized datasets.

By |August 10th, 2025|News|Comments Off on MCL Research on Eosinophilic esophagitis (EoE) Diagnosis|

MCL Research on MRI Prostate Image Quality Assessment

Magnetic Resonance Imaging(MRI) is a non-invasive, radiation-free scanning procedure generally used to obtain images of internal organs. This imaging modality is a popular screening technique for Prostate Cancer. A Prostate MRI may be used to detect prostate cancer, determine the requirement for biopsy, guide needles during targeted MRI biopsy, or detect the spreading of cancer to neighboring areas. Current standards of MRI acquisition still lead to errors, like false detections, where patients are unnecessarily sent to biopsy, or missed detections, where existing tumors remain undetected. A good quality MRI is essential to ensure that Prostate Cancer is diagnosed on time.

An MRI has several sequences, namely T2W, ADC, and DCE. For an MRI to be of diagnostic quality, atleast two of the three sequences must independently be of diagnostic quality. Errors/artifacts may be present in some or all of these sequences. Some common artifacts include motion artifacts, rectal gas, hip prosthesis, etc., that affect the quality of the MRI.

In order to assess the quality of an MRI, we train independent models for each of these sequences. While MRI images are volumetric, we treat each slice of the MRI independently. 2D Haar Wavelet Transform is applied to extract features from the LL, LH, HL, and HH bands. These features are extracted at two different resolutions. The Discriminant Feature Test(DFT) is used to reduce the feature dimension by removing features with a high DFT loss. An XGBoost Classifier is then trained using these selected features to predict whether each slice of the MRI is of satisfactory quality or not. The quality predictions from each of the three sequences are then combined to obtain the final MRI quality prediction. This approach is light-weight, efficient, and explainable, with [...]

By |August 3rd, 2025|News|Comments Off on MCL Research on MRI Prostate Image Quality Assessment|

MCL Research on Biomarker Prediction for Kidney Cancer

The tumor microenvironment includes many types of cells around the tumor. Doctors often assess it using biomarkers like PD-L1 or CD68. To measure how many cells express these markers—called positive cells—we use image analysis and machine learning models to identify positive cells and compute their count and ratio. Usually, immunohistochemistry (IHC) images are used as the input of the model because they are relatively low-cost, while multiplex immunofluorescence (IF) images are used as ground truth due to their high accuracy. A major research goal is to predict positive cell locations from IHC images.

Our current work explores the use of the Green U-shaped Learning (GUSL) pipeline to align input IHC images with the ground truth IF images. GUSL is well-suited for this task because it enables pixel-wise prediction from coarse to fine resolution. It can detect positive cells at a coarse level and progressively refine predictions. GUSL has also shown strong performance in related tasks like kidney segmentation.

Another approach we explore is using GUSL to generate predictions on other medical images, such as H&E-stained images, DAPI, and LAP2. By producing segmentation results from H&E, DAPI, LAP2, and IHC inputs, and then taking a weighted average, we aim to further improve prediction accuracy.Currently, many machine learning methods have been developed to solve this problem, but they often suffer from high computational cost (FLOPs) and large model size. In addition, the limited size of medical datasets presents another major challenge. Green learning offers a promising solution to these issues and contributes to noninvasive biomarker prediction in this research field, helping reduce the need for expensive and labor-intensive staining methods.

By |July 27th, 2025|News|Comments Off on MCL Research on Biomarker Prediction for Kidney Cancer|

MCL Research on Wavelet-Based Green Learning

Wavelet-based Green Learning (GreenWave) is a new image classification framework that combines the multi-scale power of wavelet transforms with the efficiency and interpretability of Green Learning principles. It avoids backpropagation and replaces traditional deep learning architectures with a transparent, feedforward pipeline.

At its core, GreenWave begins by applying a discrete wavelet transform (DWT)—typically using Haar wavelets—to each image, capturing both local and global spatial structures at multiple resolutions. It extracts features from wavelet subbands (like LL, LH, HL, HH) as well as local image patches from different regions (e.g., east, south, west, north). These features are used to construct class templates via averaging over training examples.

GreenWave operates in three rounds of classification:1. Round-1 classifies easy samples using cosine similarity between the input and class templates (one-vs-rest). It uses confidence metrics (like entropy) to decide which samples are “easy” and can exit the pipeline early.2. Round-2 focuses on semi-hard samples using updated templates and discriminant feature test (DFT) masks to emphasize class-informative coefficients. It also introduces one-vs-one templates to resolve class confusion.3. Round-3 targets the hardest samples using further refined templates and updated confusion masks, maximizing accuracy while maintaining interpretability.Throughout all stages, GreenWave uses cosine similarity as its feature-matching metric and XGBoost classifiers for decision learning, completely bypassing gradient-based training.

Overall, GreenWave demonstrates that a non-backpropagation, wavelet-template-based system can achieve near state-of-the-art performance while being highly efficient, explainable, and modular. This makes it an ideal choice for low-resource or transparent AI applications.

By |July 20th, 2025|News|Comments Off on MCL Research on Wavelet-Based Green Learning|