Retinal Prosthesis Dissertation - Student Home Pages

More documents

Recommendations

Info

2.6.1 MATLAB representation of epi_retinal approach AER protocol Camera stream Sender chip Digital address stream (AER) Receiver chip Actual pulse stream <strong>Retinal</strong> implant 32 x 32 image Figure 20 Simulation context diagram (level 0) In practice the camera would be affixed to specialised headgear or in the case of a miniaturised camera to bespoke spectacle frames. The power supply for the camera would be attached to a belt, also containing the `sender’ chip (responsible for conversion to AER). After propagation of AER to the `receiver’ chip, wireless telemetry could be adopted[169]. The receiver chip would be sited behind the ear similar to the procedure presently adopted for cochlear implants [101]. Although some early papers [56] suggest the possibility of incorporating the in vivo portion of the receiver chip inside the eyeball itself this adds extra complication to present telemetry communication already in use. Extra complication such as restriction of eyeball movement (necessary for efficient inductive coupling), distance of telemetry (unfeasible - from external to the skull to the eyeball), extra mass\size and extra power dissipation within the eyeball being greater than achieving without breaching safety guidelines. This document addresses the issue of prototype retinal prostheses without considering extra telemetry issues such as those outlined which are best relegated to future work. The wiring from the subcutaneous portion of the receiver chip is presently (10/07/2012) limited to 256 wires into the eyeball due to the size limitation (5mm) of the incision [54] which can safely be made without risk of biological damage. Given present research into nanowire technology this limit may potentially increase. 47 of 200
2.6.2 FPGA representation of epi_retinal approach The following diagram (figure 21) gives a basic overview of the epi_retinal prosthesis. The sender chip receives the camera output and converts it to an AER protocol[170]. This serial communication of a stream of pulses is wired from the sender chip to the receiver chip. In this diagram the separation of the receiver chip into two distinct parts i.e. external to the body and internal to the body is not shown, this is ably discussed in other papers [53]. The action of the receiver chip is to convert the serial transmission into the parallel form required for transmission to the retinal implant incorporating timing considerations, to form biphasic pulses. The implant (Addressing the implant) is then addressed in the sense that all wires now entering the eyeball carry a separate stream of information for each electrode to be driven by the post processing electrode drivers attached to the electrode array. AER protocol Receiver. <strong>Retinal</strong> implant. PISO Sender. Digital address stream (AER) Serial to parallel conversion Timing considerations Addressing the implant Form biphasic pulses Electrode array Control/ addressing Figure 21 FPGA view of processing 48 of 200
Page 1 and 2: An Address Event Representation (AE
Page 3 and 4: Abstract\Foreword This document pro
Page 5 and 6: Contents An Address Event Represent
Page 7 and 8: --Appendix E FPGA Outputs .........
Page 9 and 10: Figure 48 receiver rtl_16 .........
Page 11 and 12: Chapter 1 Introduction/research aim
Page 13 and 14: foveola (fovea pit) there is a one
Page 15 and 16: NB that the photoreceptors of the f
Page 17 and 18: electrodes to be driven implies sti
Page 19 and 20: Typically AER is used as a multi se
Page 21 and 22: Real time - innerpulse relationship
Page 23 and 24: the post processing stage of this w
Page 25 and 26: Appendix C: FPGA Sender chip Append
Page 27 and 28: Red (660nm) R / G Red ( 620750nm )
Page 29 and 30: 1 0 1 1 0 0 1 1 0 1 1 1 Table 3 `xo
Page 31 and 32: Adaptive linear combiner w 0 1 Let
Page 33 and 34: is correct (one class) and -1 (the
Page 35 and 36: x2 Linear separation 1.00 0.90 0.80
Page 37 and 38: This is also the Cartesian co-ordin
Page 39 and 40: 2.4 Comparison to Frame Based Repre
Page 41 and 42: Typical GOP structure (Typically an
Page 43 and 44: point is an event occurs for spike
Page 45 and 46: 2.5.1 Files in Appendix A “ycut.m
Page 47: MPEG-2 setup AER setup Camera Camer
Page 51 and 52: Chapter 3 Concepts An epiretinal im
Page 53 and 54: AER Transmission lines INPUT image
Page 55 and 56: electrical pulse generated is calle
Page 57 and 58: Figure 25 Retinal colour processing
Page 59 and 60: cells to modulate this luminance pa
Page 61 and 62: L+ M- + - R-G G-R B-Y Y-B Note: L(r
Page 63 and 64: 3.6.2 Retinal operations Light reac
Page 65 and 66: quantified by number of cycles pres
Page 67 and 68: (Where * is the convolution operato
Page 69 and 70: T frame C * R * M p Tpacket i.e. Tp
Page 71 and 72: e relaxed and from (2) the temporal
Page 73 and 74: one tw o three four five six seven
Page 75 and 76: 3.8.1 Other test images For other b
Page 77 and 78: Tspike (4ms) Ispike (16ms: interspi
Page 79 and 80: INDIGO ORANGE YELLOW MAGENTA CYAN B
Page 81 and 82: 4.1 Sender concepts From chapter on
Page 83 and 84: pixel must equate to 0.02/1024 i.e.
Page 85 and 86: Clocking hierarchy (32 by 32 image)
Page 87 and 88: the number of address bits will alt
Page 89 and 90: Translation report, (3) Map report,
Page 91 and 92: 90 of 200 CLKIN_IN RST_IN pixelcloc
Page 93 and 94: incorporate colour planes for each
Page 95 and 96: Chapter 5 Receiver chip The followi
Page 97 and 98: 5.2 Power Analysis Xilinx FPGAs hav
Page 99 and 100:
98 of 200 produce_wire _outputs Ins
Page 101 and 102:
5.5.1 Incoming (short) AER stream T
Page 103 and 104:
Receiver Red plane r1 DAC (4-bit) T
Page 105 and 106:
5.8.2 Electrode size and positionin
Page 107 and 108:
sequence of wiring from the receive
Page 109 and 110:
does this is to inject an equivalen
Page 111 and 112:
6.2.2 Envisaged retinal array This
Page 113 and 114:
a monochrome camera in this space i
Page 115 and 116:
632mW) thus extending battery life
Page 117 and 118:
For the implemented/structural case
Page 119 and 120:
The sender and receiver circuitry p
Page 121 and 122:
Bibliography 1. Woodburn R. Murray
Page 123 and 124:
38. Banks, D.J., P. Degenaar, and C
Page 125 and 126:
74. Freeman, J.A., Skapura, D. M.,
Page 127 and 128:
109. Weiland, J.D., et al. Progress
Page 129 and 130:
141. Indiveri G. Chicca E. Douglas
Page 131 and 132:
172. Singh, P.R., et al. A matched
Page 133 and 134:
206. Stieglitz, T., et al. Developm
Page 135 and 136:
xmixedsource; numberOfFrames = 8; f
Page 137 and 138:
%check {k} =imread (['D:\abc\subima
Page 139 and 140:
%Two for loops the first (outer loo
Page 141 and 142:
%Row break rr6c1=000; rr6c2=000; rr
Page 143 and 144:
--Appendix B FPGA Test setup librar
Page 145 and 146:
stream_blue_pulse_count: out std_lo
Page 147 and 148:
DVI_XCLK_P clock_25MHz, spike_cloc
Page 149 and 150:
use IEEE.STD_LOGIC_UNSIGNED.ALL; --
Page 151 and 152:
--Appendix C FPGA Sender chip libra
Page 153 and 154:
-- else -- resit '1', CLKDV_OUT =>
Page 155 and 156:
FPGA Receiver (structural) chip --A
Page 157 and 158:
FPGA Receiver (structural) chip --E
Page 159 and 160:
FPGA Receiver (structural) chip --r
Page 161 and 162:
FPGA Receiver (structural) chip blu
Page 163 and 164:
FPGA Receiver (structural) chip con
Page 165 and 166:
FPGA Receiver (structural) chip --s
Page 167 and 168:
FPGA Receiver (structural) chip --
Page 169 and 170:
FPGA Receiver (structural) chip --
Page 171 and 172:
FPGA Receiver (structural) chip IO_
Page 173 and 174:
Number with an unused LUT 18 219 8%
Page 175 and 176:
IO Utilization: Number of IOs: 26 N
Page 177 and 178:
The Slice Logic Distribution report
Page 179 and 180:
Router effort level (-rl): Standard
Page 181 and 182:
oming_clock | HOLD | 0.519ns| | 0|
Page 183 and 184:
Part | xc5vlx50tff1136-3 | Process
Page 185 and 186:
Selected Device: 5vlx50tff1136-3 Sl
Page 187 and 188:
used in combination with MAP -timin
Page 189 and 190:
Data Sheet report: ----------------
Page 191 and 192:
“For these implantable devices to
Page 193 and 194:
microstimulator with a 1:4 demultip
Page 195 and 196:
“Medical experiments have estimat
Page 197 and 198:
A Retinomorphic Vision System “In
Page 199 and 200:
“The common language of neuromorp
show all

Retinal Prosthesis Dissertation - Student Home Pages

Create successful ePaper yourself

Delete template?

Save as template?