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In the last years a number of counterforensics tools have been proposed. Although most of them are heuristic and designed ad hoc, lately a formal approach to this problem, rooted in transportation theory, has been pursued. This paper follows this path by designing optimal attacks against histogrambased detectors where the detection region is non-convex. The usefulness of our strategy is demonstrated...
Recently, approaches utilizing spatial-temporal features have achieved great success in human action classification. However, they typically rely on bag-of-words (BoWs) model, and ignore the spatial and temporal structure information of visual words, bringing ambiguities among similar actions. In this paper, we present a novel approach called sequential BoWs for efficient human action classification...
Human activity recognition is a crucial area of computer vision research and applications. The goal of human activity recognition aims to automatically analyze and interpret ongoing events and their context from video data. Recently, the bag of visual words (BoVW) approach has been widely applied for human action recognition. Generally, a representative corpus of videos is used to build the Visual...
Pedestrian tracking is becoming increasingly important for intelligent vehicles to improve the safety on road. Vision based pedestrian tracking with moving cameras faces notorious challenges. The classical background subtraction technique in surveillance applications is no longer applicable for Advanced Driver Assistance Systems (ADASs). In this paper, we propose a vision based pedestrian tracking...
In recent years, large-scale image retrieval has been shown remarkable potential in real-life applications. To reduce retrieval time as searched database may contain thousands of images, Inverted Indexing is the basic technique, given images are represented by Bag-of-Words model. However, one major limitation of both standard Inverted Index and Bag-of-Words model is that they ignore spatial information...
Detecting pedestrians is a challenging problem owing to the motion of the subjects, the camera and the background and to variations in pose, appearance, clothing, illumination and background clutter. The Region Covariance Matrix (RCM) descriptors show experimentally significantly out-performs existing feature sets for pedestrian detection. In this paper, we present an efficient features extraction...
In this paper we present the preliminary results of our research on face detection which show that it is possible to significantly improve the performance of a single strong classifier (in terms of high detection rate and reduced number of false positives) by adapting the detection threshold to each input image instead of using the fixed thresholds learned in the training step. Moreover, if this adaptive...
Manual annotation of images is usually a mandatory task in many applications where no knowledge about the image is available. In presence of huge number of images, this task becomes very tedious and prone to human errors. In this paper, we contribute in automatic annotation of ancient manuscripts by discovering manuscript calligraphy. Ancient manuscripts count a very large number of Persian and Maghrebi...
The setup of PET scanners usually requires an external positron source. A correct setup procedure has to ensure that the detectors are calibrated for gain adjustments, photopeak locations, and positioning maps for individual detector crystals. In order to verify the quality of the setup on a daily basis, daily quality checks are performed where the variations are checked with an external source and...
The separation of neutron and gamma-ray events in organic-liquid scintillators is of significant importance for nonproliferation applications. Typically pulse shape discrimination (PSD) technique is used to differentiate neutron distribution from gamma-ray distribution. However, one of the challenges remains whether the scintillator's PSD is affected with respect to the particle interaction position...
The R3B High-Resolution Neutron Time-of-Flight Spectrometer consists of up to 30 double planes each containing 100 sub modules of plastic scintillators which are read out on the far ends by two PMTs. For these 6000 channels a new compact and modular readout system has been developed. The electronics setup is divided into 16 channel amplifier and fast comparator boards. Digitization units using FPGA...
This work compares the PSD performance of two systems: one digital (NI PXI-5124) and one analog (Mesytec MPD4). Both systems were optimized for the best possible PSD performance, when using the same data acquisition system: PXI-5124, having 12 bit resolution, 10 V pulse-height dynamic range, and a 200 MHz sampling rate. Measurement conditions were kept identical between systems. A 5×5″ Organic-Liquid...
One of the challenging applications of PET is implementing it for in-beam PET, which is an in situ monitoring method for charged particle therapy. For this purpose, we previously proposed the world's first open-type geometries which we named OpenPET. For in-beam PET, careful designing and testing of detectors are important because secondary particles generated in a target degrade detector performance...
Silicon Photomultipliers (SiPMs) are rapidly developing photosensitive devices which are already used as an alternative to photomultipliers (PMT) in the newly developed calorimeters for high-energy physics. Nevertheless, they do have some disadvantages, namely relatively high noise and limited dynamic range, which is caused by a fixed number of pixels. Two types of SiPMs with a very high pixel density...
MR compatible PET is an attractive hybrid modality for preclinical small animal studies. Small ring diameter PET systems, such as those needed to fit inside an MR bore, tend to suffer from radial blurring due to parallax error away from the center of the FOV. To reduce this error a phoswich design can be adopted where layers of different scintillation materials are identified by decay time characteristics...
Depth of interaction detector is essential to achieve high spatial resolution and high sensitivity. Our group has developed an isotropic 3D detector, X'tal cube. For the crystal block, a laser processing was applied to a monolithic crystal to generate laser-processed boundaries (LPBs) inside the crystal block. The LPB is expected to give appropriate photon scattering effect as well as reduction of...
Digital Photon Counters (DPCs) are a new technology capable of detecting light similar to a Silicon Photomultiplier. In previous work we characterized the Philips DPC-3200-22_C DPC array for use in small-animal PET. Among other performance aspects studied was a reduction in detector efficiency from Neighbor Logic (NL) malfunction. NL forces neighboring DPC elements into a readout cycle after the first...
In this paper, we present a real-time and energy-efficient multi-scale object detector using Histogram of Oriented Gradient (HOG) features and Support Vector Machine (SVM) classification. Parallel detectors with balanced workload are used to enable processing of multiple scales and increase the throughput such that voltage scaling can be applied to reduce energy consumption. Image pre-processing is...
Oil depot detection in high-resolution images is a challenging task due to the complicated background. This paper aims at further investigating this problem and presents an approach to detect oil depots in a hierarchical manner. Firstly, the Ellipse and Line Segment Detector (ELSD) which guards against false positives is applied to detect elliptical arcs in the image. Afterwards, the Histograms of...
In this paper, a simple and fast algorithm was proposed to detect face. Firstly, some interest points marking skin regions were searched by only using simple chrominance Cr information instead of simultaneously using chrominance Cr and Cb. And then, a conventional and popular AdaBoost algorithm was employed to make a decision whether around the detected interest points was there face and then located...
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