Browsing by Subject "Discrete wavelet transforms"

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    İnsan hareketlerinin vibrasyon ve PIR algılayıcıları kullanılarak sınıflandırılması
    (IEEE, 2012-04) Yazar, Ahmet; Çetin, A. Enis; Töreyin, B. U.
    Yalnız yaşayan yaşlı ve bakıma muhtaç kişilerin yere düşmelerinin kısa sürede tespit edilmesi önemli bir sorundur. Bu bildiride, sismik ve pasif kızılberisi algılayıcılar kullanarak, belirli bir alanda yere düşme olayının tespit edilebilmesi için bir yöntem önerilmiştir. Sınıflandırma amacıyla, hızlı Fourier dönüşümü, mel-frekansı kepstral katsayıları ve ayrık dalgacık dönüşümü teknikleri kullanılarak farklı öznitelik vektörleri çıkarılmıştır. Sismik işaretler, destek vektör makineleri ile ‘düşme’ ve ‘düşme değil’ olarak iki farklı sınıfa ayrılmıştır. Pasif kızılberisi algılayıcının, belirli bir alanda hareket eden bir kişiyi tespit etmesinden sonra, sismik algılayıcının ve pasif kızılberisi algılayıcının kararları tümleştirilerek kişinin düşüp düşmediği tespit edilmektedir. Önerdiğimiz sistem gerçek zamanlı olarak standart bir bilgisayarda çalışabilmektedir.
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    A multi-modal video analysis approach for car park fire detection
    (Elsevier, 2013) Verstockt, S.; Hoecke, S. V.; Beji, T.; Merci, B.; Gouverneur, B.; Çetin, A. Enis; Potter, P. D.; Walle, R. V. D.
    In this paper a novel multi-modal flame and smoke detector is proposed for the detection of fire in large open spaces such as car parks. The flame detector is based on the visual and amplitude image of a time-of-flight camera. Using this multi-modal information, flames can be detected very accurately by visual flame feature analysis and amplitude disorder detection. In order to detect the low-cost flame related features, moving objects in visual images are analyzed over time. If an object possesses high probability for each of the flame characteristics, it is labeled as candidate flame region. Simultaneously, the amplitude disorder is also investigated. Also labeled as candidate flame regions are regions with high accumulative amplitude differences and high values in all detail images of the amplitude image's discrete wavelet transform. Finally, when there is overlap of at least one of the visual and amplitude candidate flame regions, fire alarm is raised. The smoke detector, on the other hand, focuses on global changes in the depth images of the time-of-flight camera, which do not have significant impact on the amplitude images. It was found that this behavior is unique for smoke. Experiments show that the proposed detectors improve the accuracy of fire detection in car parks. The flame detector has an average flame detection rate of 93%, with hardly any false positive detection, and the smoke detection rate of the TOF based smoke detector is 88%.
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    Watermarking based on discrete wavelet transform and q-deformed chaotic map
    (Elsevier Ltd, 2017) Behnia, Sohrab; Yahyavi, Mohammad; Habibpourbisafar, Reza
    Hierarchy of one-dimensional ergodic chaotic maps with Tsallis type of q-deformation are studied. We find that in the chaotic region, these maps with q-deformation are ergodic as the Birkhoff ergodic theorem predicts. q-deformed maps are defined as ratios of polynomials of degree N. Hence, by using the Stieltjes transform approach (STA), invariant measure is proposed. In addition, considering Sinai-Ruelle-Bowen (SRB) measure, Kolmogorov-Sinai (KS) entropy for q-deformed maps is calculated analytically. The new q-deformed scheme have ability to keep previous significant properties such as ergodicity, sensitivity to initial condition. By adding q-parameter to the hierarchy in order increase the randomness and one-way computation, we present a new scheme for watermarking. The introduced algorithm tries to improve the problem of failure of encryption such as small key space, encryption speed and level of security. To illustrate the effectiveness of the proposed scheme, some security analyses are presented. By considering the obtained results, it can be concluded that, this scheme have a high potential to be adopted for watermarking. It can be concluded that, the proposed novel watermarking scheme for image authentication can be applied for practical applications. © 2017 Elsevier Ltd