Visual Prosthesis Based on Optic Nerve Stimulation with Penetrating Electrode Array - Artificial Sight: Basic Research, Biomedical Engineering, and Clinical Advances - page 202

Figure 10.13. The process of visual information extraction: (a) original image, (b) the
image after edge following, (c) the image after edge detection, and (d) the image after
dilation based on edge image.
to implement other algorithms by our DSP image processing platform. Once
more advanced algorithms are fulfilled, the basic function of visual information
extraction of retina can be replaced by our optic nerve prosthesis.
Neural Electrical Stimulator
According to the experiment results of Claude Veraart et al., the stimulation
based on optic nerve needs biphasic current pulses with variable amplitudes
(from several microamperes up to several milliamperes), pulse duration (from
several microseconds up to hundreds of microseconds) and pulse frequency.
Then multiple biphasic current pulses make up one pulse train.
Figure 10.14. The visual information extraction by DSP: (a) original image captured by
micro-camera, (b) the image after edge detection by DSP.