13 research outputs found

    Evaluation of the potential of aerial thermal imagery to generate 3D point clouds

    Get PDF
    This research evaluates the ability of thermal images obtained from aerial platforms to produce 3D point clouds. In this study, the thermal camera is first calibrated. Then, in order to avoid data redundancy, the key frames of the obtained thermal video are separated from other frames. Afterwards, the point clouds are generated and then the thermal ortho image is created from the key frames. The evaluation is done using visible orthophoto, ground control points and the linearity of the edges of buildings extracted from thermal images. The results of this study show that the thermal ortho image matches the visible ortho image with a good accuracy in the study area. Moreover, the standard deviation of the edges of the buildings has been calculated for a number of reconstructed buildings in thermal ortho with proper dispersion. 77% of the measurements taken from the edges of the buildings coincide with a straight line with an accuracy of better than two pixels, and about half of these values are extracted with an accuracy of better than a pixel

    Face Detection of Thermal Images in Various Standing Body-Pose using Facial Geometry

    Get PDF
     Automatic face detection in frontal view for thermal images is a primary task in a health system e.g. febrile identification or security system e.g. intruder recognition. In a daily state, the scanned person does not always stay in frontal face view. This paper develops an algorithm to identify a frontal face in various standing body-pose. The algorithm used an image processing method where first it segmented face based on human skin’s temperature. Some exposed non-face body parts could also get included in the segmentation result, hence discriminant features of a face were applied. The shape features were based on the characteristic of a frontal face, which are: (1) Size of a face, (2) facial Golden Ratio, and (3) Shape of a face is oval. The algorithm was tested on various standing body-pose that rotate 360° towards 2 meters and 4 meters camera-to-object distance. The accuracy of the algorithm on face detection in a manageable environment is 95.8%. It detected face whether the person was wearing glasses or not

    Aprendizaje evolutivo supervisado: Uso de histograma de gradiente y algoritmo de enjambre de partículas para detección y seguimiento de peatones en secuencia de imágenes infrarrojas

    Get PDF
    Recently, tracking and pedestrian detection from various images have become one of the major issues in the field of image processing and statistical identification.  In this regard, using evolutionary learning-based approaches to improve performance in different contexts can greatly influence the appropriate response.  There are problems with pedestrian tracking/identification, such as low accuracy for detection, high processing time, and uncertainty in response to answers.  Researchers are looking for new processing models that can accurately monitor one's position on the move.  In this study, a hybrid algorithm for the automatic detection of pedestrian position is presented.  It is worth noting that this method, contrary to the analysis of visible images, examines pedestrians' thermal and infrared components while walking and combines a neural network with maximum learning capability, wavelet kernel (Wavelet transform), and particle swarm optimization (PSO) to find parameters of learner model. Gradient histograms have a high effect on extracting features in infrared images.  As well, the neural network algorithm can achieve its goal (pedestrian detection and tracking) by maximizing learning.  The proposed method, despite the possibility of maximum learning, has a high speed in education, and results of various data sets in this field have been analyzed. The result indicates a negligible error in observing the infrared sequence of pedestrian movements, and it is suggested to use neural networks because of their precision and trying to boost the selection of their hyperparameters based on evolutionary algorithms

    Finger vein recognition using two parallel enhancement ppproachs based fuzzy histogram equalization

    Get PDF
    This paper evaluates a set of enhancement stages for finger vein enhancement that not only has low computational complexity but also high distinguishing power. This proposed set of enhancement stages is centered around fuzzy histogram equalization. Two sets of evaluation are carried out: one with the proposed approach and one with another unique approach that was formulated by rearranging and cropping down the preprocessing steps of the original proposed approach. To extract features, a combination of Hierarchical Centroid and Histogram of Gradients was used. Both enhancement stages were evaluated with K Nearest Neighbor and Deep Neural Networks using 6 fold stratified cross validation. Results showed improvement as compared to three latest benchmarks in this field that used 6-fold validation

    PEDESTRIAN SEGMENTATION FROM COMPLEX BACKGROUND BASED ON PREDEFINED POSE FIELDS AND PROBABILISTIC RELAXATION

    Get PDF
    The wide use of cameras enables the availability of a large amount of image frames that can be used for people counting or to monitor crowds or single individuals for security purposes. These applications require both, object detection and tracking. This task has shown to be challenging due to problems such as occlusion, deformation, motion blur, and scale variation. One alternative to perform tracking is based on the comparison of features extracted for the individual objects from the image. For this purpose, it is necessary to identify the object of interest, a human image, from the rest of the scene. This paper introduces a method to perform the separation of human bodies from images with changing backgrounds. The method is based on image segmentation, the analysis of the possible pose, and a final refinement step based on probabilistic relaxation. It is the first work we are aware that probabilistic fields computed from human pose figures are combined with an improvement step of relaxation for pedestrian segmentation. The proposed method is evaluated using different image series and the results show that it can work efficiently, but it is dependent on some parameters to be set according to the image contrast and scale. Tests show accuracies above 71%. The method performs well in other datasets, where it achieves results comparable to stateof-the-art approaches

    Gaussian mixture model classifiers for detection and tracking in UAV video streams.

    Get PDF
    Masters Degree. University of KwaZulu-Natal, Durban.Manual visual surveillance systems are subject to a high degree of human-error and operator fatigue. The automation of such systems often employs detectors, trackers and classifiers as fundamental building blocks. Detection, tracking and classification are especially useful and challenging in Unmanned Aerial Vehicle (UAV) based surveillance systems. Previous solutions have addressed challenges via complex classification methods. This dissertation proposes less complex Gaussian Mixture Model (GMM) based classifiers that can simplify the process; where data is represented as a reduced set of model parameters, and classification is performed in the low dimensionality parameter-space. The specification and adoption of GMM based classifiers on the UAV visual tracking feature space formed the principal contribution of the work. This methodology can be generalised to other feature spaces. This dissertation presents two main contributions in the form of submissions to ISI accredited journals. In the first paper, objectives are demonstrated with a vehicle detector incorporating a two stage GMM classifier, applied to a single feature space, namely Histogram of Oriented Gradients (HoG). While the second paper demonstrates objectives with a vehicle tracker using colour histograms (in RGB and HSV), with Gaussian Mixture Model (GMM) classifiers and a Kalman filter. The proposed works are comparable to related works with testing performed on benchmark datasets. In the tracking domain for such platforms, tracking alone is insufficient. Adaptive detection and classification can assist in search space reduction, building of knowledge priors and improved target representations. Results show that the proposed approach improves performance and robustness. Findings also indicate potential further enhancements such as a multi-mode tracker with global and local tracking based on a combination of both papers

    The Usability of Unmanned Aerial Vehicles (UAVs) for Pedestrian Observation

    Get PDF
    The monitoring of pedestrian activity is challenging, primarily because its traffic levels are typically lower and more variable than those of motorized vehicles. Compared with other on-the-ground observation tools, unmanned aerial vehicles (UAVs) could be suitable for counting and mapping pedestrians in a reliable and efficient way. Thus, this study establishes and tests a new method of pedestrian observation using UAVs. The results show that UAV observations demonstrate high levels of interrater reliability (intraclass correlation coefficient = 0.99) and equivalence reliability (Cronbach’s α = .97 with on-the-ground counts and .73 with Google Street View). Practical implications of the new tool are discussed

    DEVELOPMENT OF GRASS-ROOTS DATA COLLECTION METHODS IN RURAL, ISOLATED, AND TRIBAL COMMUNITIES

    Get PDF
    While extensive procedures have been developed for the collection and dissemination of motor vehicle volumes and speeds, these same procedures cannot always be used to collect pedestrian data, given the comparably unpredictable behavior of pedestrians and their smaller physical size. There is significant value to developing lower cost, lower intrusion methods of collecting pedestrian travel data, and these collection efforts are needed at the local or “grass-roots” level. While previous studies have documented many different data collection methods, one newer option considers the use of drones. This study examined its feasibility to collect pedestrian data and used this technology as part of a school travel mode case study. Specific information with regard to the study methodology, permissions required, and final results are described in detail as part of this report. This study concluded that while purchasing and owning a drone requires relatively minimal investment, the initial steps required to operate a drone, along with processing time required to analyze the data collected, represent up-front barriers that may prevent widespread usage at this time. However, the use of drones and the opportunities that it presents in the long-term offer promising outcomes
    corecore