Abdessamad Ben Hamza

Dr. Abdessamad Ben Hamza

Concordia Institute for Information Systems Engineering 1455 de Maisonneuve Blvd. West, EV7.631 Montreal, QC, H3G 1M8, Canada

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2021 in Computers in Biology and Medicine
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Journal Article
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HZHasib Zunair
Hasib Zunair
AHAbdessamad Ben Hamza
Abdessamad Ben Hamza

5 April 2005 in Integrated Computer-Aided Engineering
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AHAbdessamad Ben Hamza
Abdessamad Ben Hamza
YHYun He
Yun He
HKHamid Krim
Hamid Krim
AWAlan Willsky
Alan Willsky
Pixel level image fusion refers to the processing and synergistic combination of information gathered by various imaging sources to provide a better understanding of a scene. We formulate the image fusion as an optimization problem and propose an inf

2 July 2020 in Physics in Medicine & Biology
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HZHasib Zunair
Hasib Zunair
AHAbdessamad Ben Hamza
Abdessamad Ben Hamza
Skin lesion datasets consist predominantly of normal samples with only a small percentage of abnormal ones, giving rise to the class imbalance problem. Also, skin lesion images are largely similar in overall appearance owing to the low inter-class variability. In this paper, we propose a two-stage framework for automatic classification of skin lesion images using adversarial training and transfer learning toward melanoma detection. In the first stage, we leverage the inter-class variation of the data distribution for the task of conditional image synthesis by learning the inter-class mapping and synthesizing under-represented class samples from the over-represented ones using unpaired image-to-image translation. In the second stage, we train a deep convolutional neural network for skin lesion classification using the original training set combined with the newly synthesized under-represented class samples. The training of this classifier is carried out by minimizing the focal loss function, which assists the model in learning from hard examples, while down-weighting the easy ones. Experiments conducted on a dermatology image benchmark demonstrate the superiority of our proposed approach over several standard baseline methods, achieving significant performance improvements. Interestingly, we show through feature visualization and analysis that our method leads to context based lesion assessment that can reach an expert dermatologist level.

26 April 2013 in The Visual Computer
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CLChunyuan Li
Chunyuan Li
AHAbdessamad Ben Hamza
Abdessamad Ben Hamza

4 April 2013 in Multimedia Systems
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CLChunyuan Li
Chunyuan Li
AHAbdessamad Ben Hamza
Abdessamad Ben Hamza

11 July 2023 in IEEE Transactions on Image Processing
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THTanvir Hassan
Tanvir Hassan
AHAbdessamad Ben Hamza
Abdessamad Ben Hamza
In human pose estimation methods based on graph convolutional architectures, the human skeleton is usually modeled as an undirected graph whose nodes are body joints and edges are connections between neighboring joints. However, most of these methods tend to focus on learning relationships between body joints of the skeleton using first-order neighbors, ignoring higher-order neighbors and hence limiting their ability to exploit relationships between distant joints. In this paper, we introduce a higher-order regular splitting graph network (RS-Net) for 2D-to-3D human pose estimation using matrix splitting in conjunction with weight and adjacency modulation. The core idea is to capture long-range dependencies between body joints using multi-hop neighborhoods and also to learn different modulation vectors for different body joints as well as a modulation matrix added to the adjacency matrix associated to the skeleton. This learnable modulation matrix helps adjust the graph structure by adding extra graph edges in an effort to learn additional connections between body joints. Instead of using a shared weight matrix for all neighboring body joints, the proposed RS-Net model applies weight unsharing before aggregating the feature vectors associated to the joints in order to capture the different relations between them. Experiments and ablations studies performed on two benchmark datasets demonstrate the effectiveness of our model, achieving superior performance over recent state-of-the-art methods for 3D human pose estimation.