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The advent of the Internet in these last years encouraged a considerable traffic of digital images. In the sanitary field, precisely in telemedicine branch, medical images play a very important role for therapeutic diagnoses. Thus, it is necessary to protect medical images data before transmission over the network to preserve their security and prevent unauthorized access. In this paper, a secure algorithm for biomedical images encryption scheme based on the combination of watermarking technique and chaotic function is proposed. In the proposed method, to achieve high security level performances, a non-blind hybrid watermarking technique with audio signal, Discrete Wavelet Transform is used; smoothness is also used as selected criteria; the iterations obtained by the chaotic sequences are essential and allow a good realization of the encryption process. One of the main advantages of chaos-based encryption schemes is the generation of a large number of key spaces to resist brute force attacks from the encryption algorithm. The experimental results presented in this paper attest to the invisibility and robustness of the proposed algorithm combining watermarking and chaos-based encryption.

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L’organisation Mondiale de la Santé estime que plus d’un tiers des pannes des appareils médicaux utilisés dans les pays du Sud sont causées par un réseau défaillant. Le présent article porte sur l’effet des coupures d’énergie électrique sur les appareils de radiologie à rayons X à haute fréquence, alimentés par le réseau électrique Camerounais. Des mesures des grandeurs électriques aux bornes de onze appareils de radiologie ont été effectuées à l’aide d’un analyseur de réseau et d’un kVp mètre. Le logiciel d’analyse de données Win-PQ a permis d’analyser les données enrégistrées. Les résultats montrent que, des coupures ayant eu lieu pendant la production des rayonnements X, engendrent des surtensions, ce qui augmente la quantité de rayonnement irradié au patient avec risques de blessures et détérioration d’appareillage. Ces surtensions sont d’amplitudes plus élevées lorsque les appareils fonctionnent en hyper résonance. Ceci souligne la nécessité de revoir les normes de conception et de fabrication des appareils de radiologie utilisés dans les pays du Sud dont le réseau électrique est soumis en permanence à des coupures. L’une des solutions envisageable serait de recourir aux sources d’énergies renouvelables hors réseau. The World Health Organization estimates that more than one third of the breakdowns of medical equipment used in the countries of the South are caused by a faulty network. This paper investigates the effect of power outages on high-frequency X-ray machines powered by the Cameroonian electrical grid. Measurements of electrical quantities at the terminals of eleven X-ray machines were made using a network analyzer and a kVp meter. Win-PQ data analysis software was used to analyze the recorded data. The results show that power cuts during the production of X-rays cause overvoltages, which increase the intensity of radiation delivered to the patient, and also the risk of injury and damage to the equipment. These surges are of higher amplitudes when the equipment is operating in hyper-resonance. This underlines the need to review the design and manufacturing standards of X-ray equipment used in countries in the South where the electrical network is permanently subject to power cuts. One of the solutions recommended would be the use of renewable energy sources off-grid system.