Retinal Prosthesis Dissertation - Student Home Pages

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Hence the output voltage is I R R R 2R 2R 2R 2R I/2 -V ref I/16 2R I/4 I/8 R F - + V O I OFF Figure 53 A bipolar D/A converter However the input codeword for this design is 1001, so in this case the total current entering the summing junction of the amplifier will be By making R f equal to 4R (in this case 40kΩ) then I off (offset current) will equal I/4 and therefore I s (summing junction current) will equal 5(I)/16 and 109 of 200
6.2.2 Envisaged retinal array This is the nature of the connection between the stimulator and the retinal array. The optic disc is an oval of 1.76mm by 1.92mm giving an area of 2.66mm 2 [211]. There needs to be an assurance for a colour orientated prosthesis that only one axon will be targeted. Given 50% of the ganglion cells within the optic disc are concerned with colour signals originating from the fovea [212] then this implies 1.33mm 2 housing 600, 000 fibres will have fibre areas of ≈2.2µm 2 and diameters of 1.68µm. The overlap between a 2µm diameter electrode and a 1.68µm fibre is 0.32 i.e. the encroachment upon neighbouring fibres will be 0.16µm, however as supporting tissue (0.34µm) is present before the axon we have a 0.17µm `safe’ zone before the neighbouring axon is targeted, figure 54. Figure 54 Axon clearance The stimulation site of a 2µm electrode is therefore well able to stimulate the 1µm axon of the RGC. As each electrode has an associated pitch of 50µm (0.05mm) the obtainable electrode density can be estimated by producing a square to cover the same area (1.33mm 2 ) meaning a side of ≈1.15mm. Then the number of pitches to 110 of 200
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An Address Event Representation (AE
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Abstract\Foreword This document pro
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Contents An Address Event Represent
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--Appendix E FPGA Outputs .........
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Figure 48 receiver rtl_16 .........
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Chapter 1 Introduction/research aim
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foveola (fovea pit) there is a one
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NB that the photoreceptors of the f
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electrodes to be driven implies sti
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Typically AER is used as a multi se
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Real time - innerpulse relationship
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the post processing stage of this w
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Appendix C: FPGA Sender chip Append
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Red (660nm) R / G Red ( 620750nm )
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1 0 1 1 0 0 1 1 0 1 1 1 Table 3 `xo
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Adaptive linear combiner w 0 1 Let
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is correct (one class) and -1 (the
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x2 Linear separation 1.00 0.90 0.80
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This is also the Cartesian co-ordin
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2.4 Comparison to Frame Based Repre
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Typical GOP structure (Typically an
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point is an event occurs for spike
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2.5.1 Files in Appendix A “ycut.m
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MPEG-2 setup AER setup Camera Camer
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2.6.2 FPGA representation of epi_re
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Chapter 3 Concepts An epiretinal im
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AER Transmission lines INPUT image
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electrical pulse generated is calle
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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: does this is to inject an equivalen
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
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FPGA Receiver (structural) chip blu
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FPGA Receiver (structural) chip con
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FPGA Receiver (structural) chip --s
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FPGA Receiver (structural) chip --
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FPGA Receiver (structural) chip --
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FPGA Receiver (structural) chip IO_
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Number with an unused LUT 18 219 8%
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IO Utilization: Number of IOs: 26 N
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The Slice Logic Distribution report
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Router effort level (-rl): Standard
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oming_clock | HOLD | 0.519ns| | 0|
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Part | xc5vlx50tff1136-3 | Process
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Selected Device: 5vlx50tff1136-3 Sl
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used in combination with MAP -timin
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Data Sheet report: ----------------
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“For these implantable devices to
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microstimulator with a 1:4 demultip
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“Medical experiments have estimat
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A Retinomorphic Vision System “In
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“The common language of neuromorp
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