Monica Vatteroni

Magnetically Activated Stereoscopic Vision System for Laparoendoscopic Single-Site Surgery

In this paper, the authors present an innovative vision platform for laparoendoscopic single-site (LESS) surgery based on a wired and magnetically activated 5-degrees-of-freedom robot with stereovision. The stereoscopic vision module, developed using two off-the-shelf cameras and a light emitting diodes lighting system, is mounted on the robot tip. An autostereoscopic screen is adopted to display the surgical scenario as an alternative to 3-D helmets or polarizing glasses. A rough position of the stereocamera can be determined along the abdominal wall by dragging the robot with a set of external permanent magnets (EPMs). Once the camera is set in the desired position, the EPMs provide fixation, while the internal mechanism allows fine tilt adjustment. Considering the deformable round shape of the insufflated abdomen wall and in order to replicate the precise roll motion usually provided by the endoscopists hands, this prototype embeds an actuated mechanism that adjusts the stereocamera horizon and thus prevents any visual discomfort. Finally, the platform was preliminarily tested in vivo in a LESS scenario, demonstrating its advantages for eliminating potential conflicts with the operative tools and enabling the introduction of an additional instrument through the same access port used for stereoscopic vision.

A 120-dB Dynamic Range CMOS Image Sensor With Programmable Power Responsivity

A high dynamic range CMOS image sensor providing a user-programmable power responsivity curve is presented. Each pixel integrates, besides a 4T active pixel structure, a voltage comparator and an analog memory to implement a time-to-saturation scheme while also providing the standard integrated photo-current signal. The sensor generates two 10-bit analog outputs allowing a typical dynamic range exceeding 120 dB with a temporal noise lower than 0.13% and a fixed pattern noise of 0.4% (1.7%) of the total signal swing (2 V) at low (high) irradiance without any external calibration procedures. A 140 times 140-pixel array has been fabricated in a 0.35-mum, two-poly four-metal (2P4M), 3.3-V standard CMOS technology. The chip measures 3.9 times 4.6 mm2 with a pixel pitch of 15 mum and a fill factor of 20%.

Linear–Logarithmic CMOS Pixel With Tunable Dynamic Range

A CMOS pixel with linear-logarithmic response and programmable dynamic range (DR), based on a tunable transition point, has purposely been designed for endoscopic applications. A theoretical model of the pixel was developed and validated. A chip with a 100×100 pixel array and a 12-b digital output was fabricated in a 0.35-μm technology and was fully tested, thus demonstrating state-of-the-art performance in terms of DR and noise. Intraframe DR proved to be extendable to more than 110 dB through a logarithmic compression of the signal in the light irradiation power density (LIPD) range. The measured temporal noise (pixel noise) was less than 0.22% over the full range. The architecture presented limited fixed pattern noise (FPN) due to the scheme adopted, which allowed its correction over the full signal range: FPN was 0.83% (1.37%) in the linear (logarithmic) region. Although the test chip was designed mainly for endoscopic applications, the technology may also be applied to other fields, e.g., robotics, security and industrial automation, whenever high DR is a crucial feature.

Autostereoscopic Three-Dimensional Viewer Evaluation Through Comparison With Conventional Interfaces in Laparoscopic Surgery

In the near future, it is likely that 3-dimensional (3D) surgical endoscopes will replace current 2D imaging systems given the rapid spreading of stereoscopy in the consumer market. In this evaluation study, an emerging technology, the autostereoscopic monitor, is compared with the visualization systems mainly used in laparoscopic surgery: a binocular visor, technically equivalent from the viewer’s point of view to the da Vinci 3D console, and a standard 2D monitor. A total of 16 physicians with no experience in 3D interfaces performed 5 different tasks, and the execution time and accuracy of the tasks were evaluated. Moreover, subjective preferences were recorded to qualitatively evaluate the different technologies at the end of each trial. This study demonstrated that the autostereoscopic display is equally effective as the binocular visor for both low- and high-complexity tasks and that it guarantees better performance in terms of execution time than the standard 2D monitor. Moreover, an unconventional task, included to provide the same conditions to the surgeons regardless of their experience, was performed 22% faster when using the autostereoscopic monitor than the binocular visor. However, the final questionnaires demonstrated that 60% of participants preferred the user-friendliness of the binocular visor. These results are greatly heartening because autostereoscopic technology is still in its early stages and offers potential improvement. As a consequence, the authors expect that the increasing interest in autostereoscopy could improve its friendliness in the future and allow the technology to be widely accepted in surgery.

A 120-dB Dynamic Range CMOS Image Sensor with Programmable Power Responsivity

A high dynamic range CMOS image sensor providing a user-programmable power responsivity curve is presented. Each 15 times 15mum2-pixel cell integrates, besides a 4T active pixel structure, a voltage comparator and an analog memory to implement a time-to-saturation scheme while also providing the standard integrated photo-current signal. A 140 times l40-pixel array has been fabricated in a 0.35-mum, 3.3-V standard CMOS technology. The sensor features a typical dynamic range of 120 dB with a temporal noise lower than 0.13% and a fixed pattern noise of 0.4% (1.7%) at low (high) irradiance

An innovative adaptive control strategy for sensorized left ventricular assist devices.

Nowadays advanced heart failure is mainly treated through heart transplantation. However, the low availability of donors makes the research of alternative therapies urgent. Continuous-flow left ventricular assist devices (LVADs) are going to assume a more significant role in assisting the failing heart. A recent challenge in clinical practice is the possibility to use LVAD as long-term therapy rather than as a bridge to transplantation. For this reason, more comfortable devices, able to dynamically adapt to the physiological cardiac demand in relation to the patient activity level, are needed in order to improve the life quality of patients with implants. Nevertheless, no control system has been developed yet for this purpose. This work proposes an innovative control strategy for a novel sensorized LVAD, based on the continuous collection of physical and functional parameters coming from implantable sensors and from the LVAD itself. Thanks to the proposed system, both the patient and the LVAD conditions are continuously monitored and the LVAD activity regulated accordingly. Specifically, a Proportional Integrative (PI) and a threshold control algorithms have been implemented, respectively based on flow and pressure feedbacks collected from the embedded sensors. To investigate the feasibility and applicability of this control strategy, an on-bench platform for LVADs sensing and monitoring has been developed and tested.

A linear-logarithmic CMOS pixel for high dynamic range behavior with fixed-pattern-noise correction and tunable responsivity

A CMOS image sensor with programmable dynamic range linear-logarithmic response through tunable transition point and fixed pattern noise correction is presented. Each 9.4x9.4 mum2 pixel cell integrates a 5T active pixel structure with a hard reset and an active load for the high light logarithmic behavior. A chip with a 100x100 pixel array and 12-bit digital output has been fabricated in a 0.35um, 3.3V standard CMOS technology. The dynamic range of the sensor can be changed from 45 dB to over 120 dB with decreasing pixel resolution, the temporal noise is lower than 0.22% over the full range and the fixed patter of 0.83% (1.39%) in the linear (logarithmic) region.

Experimental integration of Autoregulation Unit for left ventricular assist devices in a cardiovascular hybrid simulator

In this paper, an Autoregulation Unit (ARU) for left ventricular sensorized assist devices (LVAD) has been used with a cardiovascular hybrid simulator mimicking physiological and pathological patient conditions. The functionalities of the ARU have been demonstrating for the successful receiving and visualization of system parameters, sending of commands for LVAD speed changes, and enabling of the autonomous flow control algorithm. Experiments of speed changes and autoregulation are reported, showing the feasibility of the approach for both local and remote control of a LVAD.

Vision system for high frame rate wireless capsule endoscope

The aim of this work is the development of a custom vision system for capsule endoscopy enabling real time data stream at 20 fps. The core components of the system is a custom imager purposely developed for the target application, combined with a red, green and blue LEDs illumination system and a low power FPGA for sensor control, image compression and interfacing with transmission.

Enabling multiple robotic functions in an endoscopic capsule for the entire gastrointestinal tract exploration

Commercial endoscopic capsules are passive. Nevertheless, active capabilities such as active locomotion, drug delivery or biopsy, among others, can now be offered with the aid of robotics. New robotic functions require additional electronics for control purposes, as well as for the sensors and actuators. To avoid increasing the capsule size as a consequence, it is useful to incorporate all the electronics into the minimum number of elements, preferably in a single ASIC. This paper describes the ASIC included in a robotised capsule with the abovementioned active functions. The ASIC is a system-on-chip (SoC) integrating all the electronics needed to control the other electronic elements in the capsule. It also enables the movement of two BLDC motors, illuminates the exploration region and focuses a liquid lens used to achieve advanced vision capabilities. Details of the complete system integration are also given.