Robust realtime instrument tracking in ultrasound images for visual servoing

Abstract-Minimally invasive surgery in combination with ultrasound (US) imaging imposes high demands on the surgeon's hand-eye-coordination capabilities. A possible solution to reduce these requirements is minimally invasive robotic surgery in which the instrument is guided by visual servoing towards the goal defined by the surgeon in the US image. This approach requires robust tracking of the instrument in the US image sequences which is known to be difficult due to poor image quality. This paper presents computer vision algorithms and results of visual servoing experiments. Adaptive thresholding according to Otsu's method allows to cope with large intensity variations of the instrument echo. Subsequently applied morphological operations suppress noise and echo artefacts. A fast labelling algorithm based on run length coding allows for realtime labelling of the regions. A heuristic exploiting region size and region velocity helps to overcome ambiguities. The overall computation time is less than 10 ms per frame on a standard PC. The tracking algorithm requires no information about texture and shape which are known to be very unreliable in US image sequences. Experimental results for different instrument materials (polyvinyl chloride, polyurethane, nylon, and plexiglas) are given, illustrating the performance of the proposed approach: when chosing the appropriate material the reconstructed trajectories are smooth and only few outliers occur. As a consequence, the visual servoing loop showed to be robust and stable

Factors Associated to the Onset of Mental Illness Among Hospitalized Migrants to Italy: A Chart Review

Migration is a complex phenomenon and mental illness among immigrants remains a major matter of concern in Italy and worldwide. 243 medical and pharmacy records of patients admitted to University of Foggia hospital between 2004 and 2018 were retrospectively screened and included in the study. Socio-demographic data and clinical characteristics of inpatients were compared in those with and without first-episode of mental illness (FEMI). Subjects (140 men, 103 women; aged 34.4 ± 10.2 years) represented 6.66 ± 3.73% of all hospitalizations in 15 years. Nearly half of them (48.5%) had emigrated from other European countries. 30.8% were diagnosed with a DSM-IV TR unspecified psychosis. 103 patients (42.3%) were in first-lifetime episodes of mental illness. Factors significantly associated with FEMI were: younger age, sex (men), immigrating from Africa, poor language proficiency, lower amount of prescribed psychotropics. Mental health among immigrants is of major concern in Italy. Our findings report on factors possibly associated to the onset of mental illness among immigrant psychiatric inpatients

A SIMULATION SURVEY ON THE EFFECTS OF PROGRESSING FAULTS WITHIN THE SCAS OF A FLIGHT CONTROL ACTUATOR FOR HELICOPTERS

Stability Control Augmentation Systems (SCAS) are widely adopted to enhance the flight stability of rotary-wing aircraft operating in difficult aerodynamic conditions, such as low altitude missions, stationary flight nearby vertical walls or in presence of heavy gusts. Such systems are based upon small electro-hydraulic servosystems controlled in position through a dedicated servovalve. The SCAS operates with limited authority over the main control linkage translating the pilot input in the movement of the main flight control actuator. Being critical for the operability of the helicopter, the definition of a Prognostics and Health Management (PHM) framework for the SCAS systems would provide significant advantages, such as better risk mitigation, improved availability, and a reduction in the occurrences of unpredicted failures which still represent one of the most known downsides of helicopters. This paper provides the results of a preliminary analysis on the effects of the inception and progression of several degradation types within a simulated SCAS system. Signals usually available within such devices are hence combined with measurements provided by additional sensors to check the feasibility of a PHM system with and without dedicated sensors. The resulting features selection process shows that although the dedicated measurements are required to design a complete PHM system, it appears nonetheless possible to obtain valuable information on the health status of the SCAS system without resorting to additional sensors