Retinal Prosthesis Dissertation - Student Home Pages

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Membrane potential (mv) +30 0 -70 0 1 2 3 4 5 Time(ms) Peak to peak 100 x 50 pulses equal 5v Figure 56 AP propagating through optic nerve 6.6 Pre processing Presently the incoming image for this prototype system is held in ROM, prior to full implementation a camera would be interfaced to the FPGA, either a RGB camera or a YUV camera utilizing an intellectual property (IP) core to convert to RGB signal format. Future work could encompass the possibility of converting a camera with universal signal bus (USB) protocol to RGB format. When using an RGB or YUV camera the frame rate to be set will be determined by the partial_spike_clock frequency derived from the FPGA clock frequency. The ratio is largely determined by the image size to be transmitted e.g. for a circa 1000 pixel image a partial_spike_clock frequency of 25Mhz would expect a frame rate of 25fps and similarly a partial_spike_clock frequency of 50Mhz would expect a frame rate of 50fps for the same size of image. 6.7 Future work 117 of 200
The sender and receiver circuitry presently implemented in FPGA fabric needs to be produced in the form of two separate application specific integrated circuits (ASIC’s) to reduce the physical footprint. The power pack supplying power to the system is worn at the waist of the implant patient. Camera and receiver chip is housed on a pair of spectacles worn by the patient. The following diagram illustrates this part of the setup. Interconnection to retinal implant Receiver chip Camera power Data feed Data feed Sender chip Battery pack Belt Figure 57 Practical setup 6.7.1 Surgical implantation The microstimulator or driver circuitry (post processing interface) is implanted alongside the epiretinal electrode array. A 5mm surgical incision allows up to 256 wires to pass through; at the time of writing (February 2012). So for the implementation of a 4 by 4 image as has been implemented in this prototype 48 118 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
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cells to modulate this luminance pa
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L+ M- + - R-G G-R B-Y Y-B Note: L(r
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3.6.2 Retinal operations Light reac
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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: For the implemented/structural case
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 --
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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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