Image processing system dedicated to a visual intra-cortical stimulator

Microstimulation is a feasible method targeting visual impairment. In this paper, the authors focus on intra-cortical stimulation to cover the broader spectrum of the issue with the aim of providing a better suited visual aid. They present an overall modular architecture and focus on creating re-usable image processing tools that can be used for image simplification and recognition tasks. One of the main challenges in the image processing path is the real-time restriction; hence they resort to field-programmable gate array (FPGA) hardware acceleration. Herein they demonstrate and describe the architecture of an image feature extractor based on the difference of Gaussians that is at once accurate, generic and low on resources. This architecture also features a Huffman encoding engine that proves useful when resorting to software-hardware (SW-HW) hybrid implementations, and a technique of calibrating and calculating the phosphene map.