3D Time-of-flight distance measurement with custom - Universität ...

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DEMODULATION PIXELS IN CMOS/CCD 123 than be determined with the ratio of the spot size to the size of the photogate. Additionally it is possible to attenuate the optical power by introducing neutral density filters into the light path. This is the preferred method of changing the light intensity, since it is fairly fast and highly accurate. Camera board Chip LED-Module Figure 5.11 Optical measurement setup. Camera board Chip The signals to control the LED-module are TTL signals, generated by a digital pattern generator (sequencer, c.f. Chapter 6) that also controls the camera board, especially the demodulation gates PGL and PGR, so that modulation and demodulation are synchronous.
124 CHAPTER 5 The optical input signal: AC-Performance of LEDs Since the control signal for the LEDs is digital, we get a square wave modulated LED output signal, at least for low modulation frequencies. Figure 5.12 shows the optical output signal of the 630 nm HP-LED for different modulation frequencies. 1 MHz 10 MHz 20 MHz Figure 5.12 Speed performance and modulation shape of the LED light source for different modulation frequencies. (LED: Hewlett Packard HPWT-DH00, Detector: Siemens SFH203P photodiode) One can see from these measurements that the cut-off frequency of the 630 nm LEDs used is in the range of 20 MHz. The low-pass characteristic of the LEDs leads to an attenuation of the square waves’ harmonics for larger frequencies. This results in an optical output that gradually looks sinusoidal for frequencies larger than 5-10 MHz. Measuring the amplitude of a square- or sine-wave From Section 2.2.2 we know that sampling of a square wave with only four sampling points leads to aliasing. This is because a square wave is composed of an infinite number of harmonics. We also discussed in Chapter 2 that the fact of integrating the single sampling points over half the modulation period leads to lowpass filtering of the signal (convolution of the spectrum with a sinc-function), which decreases the measured amplitude (of the first harmonic) to 64% of the real amplitude. With our measurement setup, described above, we get a square wave modulation for lower modulation frequencies and a more sinusoidally shaped modulation for modulation frequencies beyond the LED’s cut-off frequency. To determine the amplitude of a square wave exactly one would have to use an infinitesimally small (short) integration interval for the sampling process. For our integration interval of half the modulation period, the measured amplitude, assuming 4-tap sampling of a
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3D Time-of-flight distance measurem
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To my parents
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Meinen Eltern
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II 4. Power budget and resolution l
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Abstract Since we are living in a t
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centimeter accuracy. With the singl
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X Eine elegantere Methode zur Entfe
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INTRODUCTION 1 1. Introduction One
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INTRODUCTION 3 light source observe
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INTRODUCTION 5 Propagation time, ho
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INTRODUCTION 7 Chapter 3 gives a sh
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OPTICAL TOF RANGE MEASUREMENT 9 2.
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OPTICAL TOF RANGE MEASUREMENT 13 pr
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OPTICAL TOF RANGE MEASUREMENT 15 hi
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OPTICAL TOF RANGE MEASUREMENT 17 Pu
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OPTICAL TOF RANGE MEASUREMENT 19 Ad
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OPTICAL TOF RANGE MEASUREMENT 21 pr
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OPTICAL TOF RANGE MEASUREMENT 23 wh
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OPTICAL TOF RANGE MEASUREMENT 25 δ
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OPTICAL TOF RANGE MEASUREMENT 27 c(
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OPTICAL TOF RANGE MEASUREMENT 29 A
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OPTICAL TOF RANGE MEASUREMENT 31 ph
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OPTICAL TOF RANGE MEASUREMENT 33 Ts
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OPTICAL TOF RANGE MEASUREMENT 35 f1
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OPTICAL TOF RANGE MEASUREMENT 37 an
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OPTICAL TOF RANGE MEASUREMENT 39 in
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OPTICAL TOF RANGE MEASUREMENT 41 Ss
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OPTICAL TOF RANGE MEASUREMENT 43 Fr
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OPTICAL TOF RANGE MEASUREMENT 45 1
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50 CHAPTER 3 the smearing effect, r
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52 CHAPTER 3 3.1 Silicon properties
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54 CHAPTER 3 (a) Figure 3.3 Optical
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56 CHAPTER 3 Quantum efficiency in
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58 CHAPTER 3 The different operatio
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60 CHAPTER 3 (a) (b) Depletion widt
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62 CHAPTER 3 Very special processes
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64 CHAPTER 3 1 kT Dn = ⋅ vth ⋅
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66 CHAPTER 3 The proportionality fa
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68 CHAPTER 3 difference of only 1 V
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70 CHAPTER 3 Flicker noise is cause
Page 89 and 90: 72 CHAPTER 3 A s = sf ⋅ q C ⎡ V
Page 91 and 92: 74 CHAPTER 3 amount of the charge p
Page 93 and 94: 76 CHAPTER 3 substrate (Equation 3.
Page 95 and 96: 78 CHAPTER 3 charge carriers the CT
Page 97 and 98: 80 CHAPTER 3 without causing short
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Page 101 and 102: 84 CHAPTER 3 Orbit’s 2.0µm CMOS/
Page 103 and 104: 86 CHAPTER 4 Figure 4.1 P lens Lamb
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Page 109 and 110: 92 CHAPTER 4 number of pseudo-backg
Page 111 and 112: 94 CHAPTER 4 Cmod = 1 QE(λ) = 0.65
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Page 174 and 175: IMAGING TOF RANGE CAMERAS 157 gate
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Page 178 and 179: IMAGING TOF RANGE CAMERAS 161 n+ di
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Page 182 and 183: IMAGING TOF RANGE CAMERAS 165 Power
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IMAGING TOF RANGE CAMERAS 173 Bound
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IMAGING TOF RANGE CAMERAS 175 Figur
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IMAGING TOF RANGE CAMERAS 177 Final
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IMAGING TOF RANGE CAMERAS 179 #5 #6
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SUMMARY AND PERSPECTIVE 181 7. Summ
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SUMMARY AND PERSPECTIVE 183 into th
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SUMMARY AND PERSPECTIVE 185 or phas
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188 CHAPTER 8 8.2 Typical parameter
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190 CHAPTER 8 Spectral luminous int
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192 CHAPTER 8 MCD03S: Conditions SC
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194 CHAPTER 8 MCD06S: Measurement c
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196 [BRK] Brockhaus, “Naturwissen
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198 [KAI] I. Kaisto, et al., “Opt
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200 [SP1] T. Spirig et al., “The
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ACKNOWLEDGMENTS 203 Acknowledgments
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206 Publication list 1. R. Lange, P
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