Retinal Prosthesis Dissertation - Student Home Pages

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Pigment epithelium Outer segments of photoreceptors Outer nuclear layer Cone Rod Outer plexiform layer Inner nuclear layer Inner plexiform layer Ganglion cell layer Horizontal cell Bipolar cell Amarcrine cell RGCs Parasol RGC Midget RGC Small bistratified RGC Direction of light from eye lens Figure 27 <strong>Retinal</strong> Structure This convergence of the retina, in terms of intensity signals derived from the photoreceptors is represented at the ganglionar level in terms of the receptive field concept. In this abstraction the signals arriving at a ganglion cell are represented either by an ON-OFF configuration when excitatory signals predominate [198] and depolarisation causes an action potential to be produced and propagated along the optic nerve fibre and an OFF-ON configuration when this is not the case i.e. where inhibitory signal predominate (Table 1). The centre in a primate retina is half the size of the periphery; characterised by spatial frequency, cycles per degree (c/d) 63 of 200
quantified by number of cycles present in the stimulus of a 1º visual angle. [198], the size referred to here is in terms of the centre radius compared to the peripheral radius [199]. So for a centre radius (r c ) the surround radius (r s ) will be 2r c giving an area of centre of πr 2 c and an outer area of π(2r c ) 2 giving an annulus area of 4πr 2 c - πr 2 c i.e. 3 πr 2 c meaning the relationship between centre area and annulus is 3 (Figure 2). Destination of signals On centre ganglion cell field Off centre ganglion cell field Converging signals impinging on surround only Converging signals impinging on centre only No signals reaching centre or surround Signals reaching centre and surround ganglion cell axon does not fire ganglion cell axon fires rapidly ganglion cell axon does not fire low frequency firing contentious but an off-bipolar cell field would fire contentious but an off-bipolar cell field would not fire ganglion cell axon does not fire low frequency firing Table 5 Receptive ON/OFF operation Diamete r 3.36µm When r surround equals 2r centre annulus area equals 6.65µm 2 Receptive field + + Diamete r 1.68µm function 64 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
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 and 48: MPEG-2 setup AER setup Camera Camer
Page 49 and 50: 2.6.2 FPGA representation of epi_re
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: 3.6.2 Retinal operations Light reac
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
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632mW) thus extending battery life
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For the implemented/structural case
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The sender and receiver circuitry p
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Bibliography 1. Woodburn R. Murray
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38. Banks, D.J., P. Degenaar, and C
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74. Freeman, J.A., Skapura, D. M.,
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109. Weiland, J.D., et al. Progress
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141. Indiveri G. Chicca E. Douglas
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172. Singh, P.R., et al. A matched
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206. Stieglitz, T., et al. Developm
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xmixedsource; numberOfFrames = 8; f
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%check {k} =imread (['D:\abc\subima
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%Two for loops the first (outer loo
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%Row break rr6c1=000; rr6c2=000; rr
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--Appendix B FPGA Test setup librar
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stream_blue_pulse_count: out std_lo
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DVI_XCLK_P clock_25MHz, spike_cloc
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use IEEE.STD_LOGIC_UNSIGNED.ALL; --
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--Appendix C FPGA Sender chip libra
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-- else -- resit '1', CLKDV_OUT =>
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FPGA Receiver (structural) chip --A
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FPGA Receiver (structural) chip --E
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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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