| The term visual prosthesis refers to any device capable of eliciting visual percept,which is known as phosphene, in an individual through electrical stimulation of any partof the visual system. It's a promising method to help bind patient regain visual ability. Thestructure of visual prosthesis contains three parts:(1) the image processing and codingsystem,(2) the wireless transmission system,(3) the implantable micro-stimulator andmicroelectrode.The development trend of visual prosthesis reflects on the following aspects: thespeed of image processing strategy, the biological safety of implantable instruments, thesteadiness of the whole system, etc. In this research, we have developed a real-timeimage processing system for visual prosthesis. Then we improved both the hardware andsoftware of this system as follow.Firstly, we designed an alterable image processing strategy for different scenes; thenwe attached extended buttons to the system to realize the new strategy. Secondly, weproposed two algorithms for image sampling based on the regional averaging algorithm:grid sampled averaging and central sampled averaging. Compared to the original one, thetwo algorithms could reduce the computation burden by90%and40%respectively. Lastbut not the least, we redesigned the circuit of the system and attached the RFtransmission part based on chip EM4094to it. We finally realized a wearable visualprosthesis system which could work steady and continuously over22h when powered bya5V*15.4Ah Li-ion battery. |
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