Research On Cochlear Implants Microelectrode Array Detection System

Cochlear implants are the most effective treatment in patients with sensorineural hearing loss. It generates an output sound signal to stimulates the body by microelectrode array of the implants end. At present quality inspection of cochlear implants’ s microelectrode array rely on artificial detection by handheld probe so that it exist disadvantage such as difficult to accurate positioning, easy to damage the electrode surface and poor consistency test. Therefore, this paper research on the related technology of the automation microelectrode array detection system, design and product test system prototype.Through the analysis of testing requirements and actual process, system’s function modules and test plan were layout and mechanical structure parts were designed. For detecting probe’s specific location and determining detecting plan, designing two level computer control system of PC upper computer and motion control card and writing control program of the detection system were carried out. Detection system prototype achieved the goal of identifying electrode ring to be detected and making probe flexibly contact with specific electrode ring automatically, which make the signal detection equipment conducting with electrode ring.Based on the requirements of microscopic visual inspection, the image process of characteristic target in automatic identification microscopic view was set up. This paper use two kinds of image resolution evaluation function to control automatic focusing mechanism, so that clear target image was accurately obtained. An improved edge-detecting algorithm based on Canny edge detection process was put forward, which make outline of the image segmentation clear, identification accurate and effect stable. Interested area was extracted by using gray-level projection principle. The characteristic target’s coordinates of probe and microelectrode were accurately extracted from this area. This paper applied process of the cost function-prediction window-target matching and proposes a multi-feature cost function to enhance the stability of target tracking to achieve the position of probe and micro electrode ring and motion tracking identification of characteristic target.For the difference demand of motion control and the contact force control, a hybrid control strategy that is suitable for the dynamic positioning of microoperation procedure and contact force detection was put forward. The relationship between the image coordinate and the reference coordinate transformation was established. Through the image deviation value calculation and finite-state machine’s control to trajectory, dynamic positioning was realized accurately. Flexible contact force’s expected range was calculated. Through analysis of contact process, equivalent model of probe and microelectrode array was set up, which achieved the goal of the contact- force’s impedance control in the expected power range.By settiing automated microelectrode array detection experiment process, the microelectrode array detection processs and steps were showed. It realized the system function of probe position and flexible contact electrode ring, and verify the validity of the motion position and force control.