Italy


Sensitive gravitational wave (GW) detectors such as that of Laser Interferometer Gravitational-wave Observatory (LIGO) realize the direct observation of GW signals that confirm Einstein’s general theory of relativity. However, it remains chal- lenges to quickly detect faint GW signals from a large number of time series with background noise under unknown probability distributions. Traditional methods such as matched-filtering in general assume Additive White Gaussian Noise (AWGN) and are far from being real-time due to its high computational complexity. To avoid these weaknesses, one-dimensional (1D) Convolutional Neural Networks (CNNs) are introduced to achieve fast online detection in milliseconds but do not have enough consideration on the trade-off between the frequency and time features, which will be revisited in this paper through data pre-processing and subsequent two-dimensional (2D) CNNs during offline training to improve the online detection sensitivity.
In this work, the input data is pre-processed to form a 2D spec- trum by Short-time Fourier transform (STFT), where frequency features are extracted without learning. Then, carrying out two 1D convolutions across time and frequency axes respectively, and concatenating the time-amplitude and frequency-amplitude feature maps with equal proportion subsequently, the frequency and time features are treated equally as the input of our following two-dimensional CNNs. The simulation of our above ideas works on a generated data set with uniformly varying SNR (2-17), which combines the GW signal generated by PYCBC and the background noise sampled directly from LIGO. Satisfying the real-time online detection requirement without noise distribution assumption, the experiments of this paper demonstrate better performance on average compared to that of 1D CNNs, especially in the cases of lower SNR (4-9).

ICPR 2020

Improving Gravitational Wave Detection with 2D Convolutional Neural Networks

signal analysis

neural networks

deep learning

ICPR 2020 is the premier international conference on Pattern Recognition, gathering leading researchers from around the world to present their latest achievements in Pattern Analysis and Recognition, applied Artificial Intelligence and Machine Learning. The topic of the year is " Putting Artificial intelligence to work on Patterns". 
For the first time, ICPR has employed a two-round review process similar to journal submissions, with new papers allowed to be submitted in either the first or second round and papers submitted in the first round and not accepted allowed to be revised and re-submitted for second round review. 

In this edition of the **ICPR 2020** Conference, there are 1407 Oral/Poster presentations organized in five Tracks: 
- Artificial Intelligence, Machine Learning for Pattern Analysis; 
- Biometrics, Human Analysis and Behavior Understanding; Computer Vision, Robotics and Intelligent Systems; 
- Document and Media Analysis; and 
- Image and Signal Processing. 

The **ICPR 2020** Main Conference program also includes 7 Keynotes from prominent world-renowned scientists, 8 Tutorials, 28 Demos, 8 Challenges, 2 Panels, as well as an Industry/Sponsor Exhibition. In addition, 41 Workshops on a range of important current and emerging research topics complete the ICPR 2020 program. 


poster


Functional MRI based on blood oxygenation level dependent (BOLD) contrast is well established as a neuroimaging technique for detecting neural activity in the cortex
of the human brain. Recent studies have shown that variations of BOLD signals in white matter are also related to neural activities both in resting state and under functional loading. We develop a comprehensive framework of detecting task-specific fiber pathways. We not only study fiber tracts as open curves with different physical features (shape, scale, orientation and position), but also incorporate the BOLD signals associated with them to find stimulus-relevant pathways. Specifically, we propose a novel Riemannian metric, which is a weighted sum of distances in product space of shapes and functions. This metric provides both a cost function for registration and a proper distance for comparison. Experimental results on real data have shown that we can cluster fiber pathways correctly by evaluating correlations
between BOLD signals and stimuli, temporal variations and power spectra of them.

A Riemannian Framework for Detecting Stimulus-Relevant Fiber Pathways


Our work is about simultaneously pixel-level retinal lesion segmentation and image-level disease classification.

Learn to Segment Retinal Lesions and Beyond

A network to solve the segmentation of ultra-high resolution images

UHRSNet: A Semantic Segmentation NetworkSpecifically for Ultra-High-Resolution Images

One of the significant challenges of deep neural networks is that the complex nature of the network prevents human comprehension of the outcome of the network. Consequently, the applicability of complex machine learning models is limited in the safety-critical domains, which incurs risk to life and property. To fully exploit the capabilities of complex neural networks, we propose a non-intrusive interpretability technique that uses the input and output of the model to generate a saliency map. The method works by empirically optimizing a randomly initialized input mask by localizing and weighing individual pixels according to their sensitivity towards the target class. Our experiments show that the proposed model interpretability approach performs better than the existing saliency map-based approaches methods at localizing the relevant input pixels. 

Furthermore, to obtain a global perspective on the target-specific explanation, we propose a saliency map reconstruction approach to generate acceptable variations of the salient inputs from the space of input data distribution for which the model outcome remains unaltered. Experiments show that our interpretability method can reconstruct the salient part of the input with a classification accuracy of 89%.

A generalizable saliency-map based interpretation of model outcome

This study attempts to use crowdsourcing to facilitate the operation of pattern-recognition-based video surveillance systems at an early stage. Target events (i.e. events to be detected during surveillance) are not frequently observed in recorded video, so achieving reliable surveillance on the basis of machine learning requires a sufficient amount of target data. Acquiring sufficient data is time-consuming. However, operating unreliable surveillance systems can induce many false alarms. Crowdsourcing is introduced to address this problem by verifying the unreliable results in data-driven surveillance. Experimental simulation conducted using monitoring video of Japanese black beef cattle demonstrates that crowdsourced verification successfully reduced false alarms in calving detection systems.

Crowdsourced Verification for Operating Calving Surveillance Systems at an Early Stage

This paper tackles on building a pattern recognition system that detects whether a pair of Japanese black beefs captured in a given image region is in a “mounting” action, which is known to be a sign critically important to be detected for cattle farmers before artificial insemination. The “mounting” action refers to a cattle’s action where a cow bends over another cow usually when either cow is in estrus. Although a pattern recognition-based approach for detecting such an action would be appreciated as being low-cost and robust, it had not been discussed much due to the complexity of the system architecture, unavailability of datasets, etc. This study presents i) our image dataset construction technique that exploits both object detection algorithm and crowdsourcing for collecting cattle pair images with labels of either “mounting” or not; and ii) a system for detecting the mounting action from any given image of a cattle pair, developed based on the dataset. Starting with an algorithm for extracting regions of cattle pairs from a video frame based on the intersection of single cattle regions, we then designed our crowdsourcing microtask in which crowd workers were given simple guidelines to annotate mounting-action-relevant labels to the extracted regions, to finally obtain a dataset. We also introduce our tandem-layered pattern recognition system trained with the dataset. The system is comprised of two serially-connected machine learning components, and is capable of more robustly detecting mounting actions even with a small amount of training data than a normal end-to-end neural network. Experimental comparisons demonstrated that our detection system was capable of detecting estrus with a precision rate of 80% and a recall rate of 76%.

Toward Building a Data-Driven System For Detecting Mounting Actions of Black Beef Cattle

Density regression has been widely employed in crowd counting. However, the frequency imbalance of pixel values in the density map is still an obstacle to improve the performance. In this paper, we propose a novel learning strategy for learning error-driven curriculum, which uses an additional network to supervise the training of the main network. A tutoring network called TutorNet is proposed to repetitively indicate the critical errors of the main network. TutorNet generates pixel-level weights to formulate the curriculum for the main network during training, so that the main network will assign a higher weight to those hard examples than easy examples. Furthermore, we scale the density map by a factor to enlarge the distance among inter-examples, which is well known to improve the performance. Extensive experiments on two challenging benchmark datasets show that our method has achieved state-of-the-art performance.

Learning Error-Driven Curriculum for Crowd Counting


State-of-the-art pedestrian detectors have achieved significant progress on non-occluded pedestrians, yet they are still struggling under heavy occlusions. The recent occlusion handling strategy of popular two-stage approaches is to build a two-branch architecture with the help of additional visible body annotations. Nonetheless, these methods still have some weaknesses. We propose in this paper a novel Mutual-Supervised Feature Modulation (MSFM) network, to better handle occluded pedestrian detection. To facilitate the MSFM module, we also propose a novel two-branch architecture, consisting of a standard full body detection branch and an extra visible body classification branch. To verify the effectiveness of our proposed method, extensive experiments are conducted on two challenging pedestrian datasets: Caltech and CityPersons, and our approach achieves superior performance compared to other state-of-the-art methods on both datasets, especially in heavy occlusion cases.

Mutual-Supervised Feature Modulation Network for Occluded Pedestrian Detection

Autism spectrum disorder (ASD) is a neuro- developmental disorder, which causes deficits in social lives. Early screening of ASD for young children is important to reduce the impact of ASD on people’s lives. Traditional screening methods mainly rely on protocol-based interviews and subjective evaluations from clinicians and domain experts, which requires advanced expertise and intensive labor. To standardize the process of ASD screening, we design a ”Responsive Social Smile” protocol and the associated experimental setup. Moreover, we propose a machine learning based assessment framework for early ASD screening. By integrating speech recognition and computer vision technologies, the proposed framework can quantitatively analyze children’s behaviors under well-designed protocols. We collect 196 stimulus samples from 41 children with an average age of 23.34 months, and the proposed method obtains 85.20% accuracy for predicting stimulus scores and 80.49% accuracy for the final ASD prediction. This result indicates that our model approaches the average level of domain experts in this ”Responsive Social Smile” protocol.

Responsive Social Smile: A Machine Learning based Multimodal Behavior Assessment Framework towards Early Stage Autism Screening


As scanners produce higher-resolution and more densely sampled images, this raises the challenge of data storage, transmission and communication within healthcare systems. Since the quality of medical images plays a crucial role in diagnosis accuracy, medical imaging compression techniques are desired to reduce scan bitrate while guaranteeing lossless reconstruction. This paper presents a lossless compression method that integrates a Recurrent Neural Network (RNN) as a 3D sequence prediction model. The aim is to learn the long dependencies of the voxel's neighbourhood in 3D using Long Short-Term Memory (LSTM) network then compress the residual error using arithmetic coding. Experiential results reveal that our method obtains a higher compression ratio achieving 15% saving compared to the state-of-the-art lossless compression standards, including JPEG-LS, JPEG2000, JP3D, HEVC, and PPMd. Our evaluation demonstrates that the proposed method generalizes well to unseen modalities CT and MRI for the lossless compression scheme. To the best of our knowledge, this is the first lossless compression method that uses LSTM neural network for 16-bit volumetric medical image compression.


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