1 cmput 412 sensing csaba szepesvári university of alberta texpoint fonts used in emf. read the...
Post on 15-Jan-2016
216 views
TRANSCRIPT
![Page 1: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/1.jpg)
1
CMPUT 412Sensing
Csaba SzepesváriUniversity of Alberta
![Page 2: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/2.jpg)
2
Defining sensors and actuators
Environment
actions
Sensations(and reward)
Controller= agent
Sensors Actuators
![Page 3: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/3.jpg)
3
Perception
SensorsUncertaintyFeatures
![Page 4: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/4.jpg)
4
How are sensors used?
![Page 5: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/5.jpg)
5
HelpMate, Transition Research Corp.
![Page 6: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/6.jpg)
6
B21, Real World Interface
![Page 7: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/7.jpg)
7
Robart II, H.R. Everett
![Page 8: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/8.jpg)
8
Savannah, River Site Nuclear Surveillance Robot
![Page 9: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/9.jpg)
9
BibaBot, BlueBotics SA, Switzerland
Pan-Tilt Camera
Omnidirectional Camera
IMUInertial Measurement Unit
Sonar Sensors
Laser Range Scanner
Bumper
Emergency Stop Button
Wheel Encoders
![Page 10: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/10.jpg)
10
Taxonomy of sensors
![Page 11: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/11.jpg)
11
Classification of Sensors Where is the information coming from?
Inside: Proprioceptive sensors motor speed, wheel load, heading of the robot,
battery status Outside: Exteroceptive sensors
distances to objects, intensity of the ambient light, unique features
How does it work? Requires energy emission? No: Passive sensors
temperature probes, microphones, CCD Yes: Active sensors
Controlled interaction -> better performance Interference
Simple vs. composite (sonar vs. wheel sensor)
![Page 12: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/12.jpg)
12
General Classification (1)
![Page 13: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/13.jpg)
13
General Classification (2)
![Page 14: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/14.jpg)
14
Sensor performance
![Page 15: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/15.jpg)
15
How Do (Simple) Sensors Work?
Analog signals Digital signals
Physical process
Environment
Electrical current
Analog to digital
conversion
0010101101010011010111010101input output
![Page 16: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/16.jpg)
16
Mathematical Models
Signal in => signal out: response Memoryless: Vout = S( Ein , Noiset) With memory: Vout = f( Vout, Ein , Noiset)
Physical process
Environment
Electrical current
Analog to digital
conversion
0010101101010011010111010101input output
Sampling rate, aliasing, dithering
![Page 17: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/17.jpg)
17
Nominal Sensor Performance Valid inputs
Emin: Minimum detectable energy Emax: Maximum detectable energy Dynamic range = Emax/Emin , or 10 log(Emax/Emin ) [dB]
power measurement or volt? (V2 ~ power) Operating range (Nmin, Nmax): Emin · Nmin · Nmax · Emax
No aliasing in the operating range (e.g., distance sens.) Response
Sensor response: S(Ein)=? Linear? (or non-linear) Hysteresis
Resolution (¢): E1-E2· ¢ ) S(E1)¼ S(E2); often ¢=min(Emin , ¢A/D )
Timing Response time (range): delay between input and output [ms] Bandwidth: number of measurements per second [Hz]
![Page 18: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/18.jpg)
18
In Situ Sensor Performance: Sensitivity
Characteristics .. especially relevant for real world environments Sensitivity:
How much does the output change with the input? Memoryless sensors: min{ [d/dE S] (Ein) | Ein } Sensors with memory: min{ f(V,Ein)/Ein | V, Ein }
Cross-sensitivity sensitivity to environmental parameters that are orthogonal
to the target parameters e.g. flux-gate compass responds to ferrous buildings,
orthogonal to magnetic north Error: ²(t) = S(t) - S(Ein(t))
Systematic: ²(t) = D(Ein(t)) Random: ²(t) is random, e.g., ²(t) ~ N(¹,¾2)
Accuracy (systemacity): 1-|D(Ein)|/Ein, e.g., 97.5% accuracy
Precision (reproducability): Rangeout/ Var(²(t))1/2
![Page 19: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/19.jpg)
19
In Situ Sensor Performance: Errors
Characteristics .. especially relevant for real world environments Error: ²(t) = S(t) - S(Ein(t))
Systematic: ²(t) = D(Ein(t)) Predictable, deterministic Examples:
Calibration errors of range finders Unmodeled slope of a hallway floor Bent stereo camera head due to an earlier collision
Random: ²(t) is random, e.g., ²(t) ~ N(¹,¾2) Unpredictable, stochastic Example:
Thermal noise ~ hue calibration, black level noise in a camera
Accuracy – accounts for systemic errors 1-|D(Ein)|/Ein, e.g., 97.5% accuracy
Precision – high precision ~ low noise Rangeout/ Var(²(t))1/2
![Page 20: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/20.jpg)
20
Challenges in Mobile Robotics
Systematic vs. random errorsError distributions
![Page 21: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/21.jpg)
21
Systematic vs. Random? Sonar sensor:
Sensitivity to: material, relative positions of sensor and target (cross-sensitivity)
Specular reflections (smooth sheetrock wall; in general material, angle)
Systematic or random? What if the robot moves? CCD camera:
changing illuminations light or sound absorbing surfaces
Cross-sensitivity of robot sensor to robot pose and robot-environment dynamics rarely possible to model -> appear as random errors systematic errors and random errors might be well defined
in controlled environment. This is not the case for mobile robots !!
![Page 22: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/22.jpg)
22
Error Distributions A convenient assumption: ²(t) ~ N(0,§) WRONG!
Sonar (ultrasonic) sensor Sometimes accurate, sometimes overestimating Systematic or random? “Operation modes” Random => Bimodal:
- mode for the case that the signal returns directly- mode for the case that the signals returns after multi-path reflections.
Errors in the output of a stereo vision system (distances)
Characteristics of error distributions Uni- vs. Multi-modal, Symmetric vs. asymmetric Independent vs. dependent (decorrelated vs. correlated)
![Page 23: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/23.jpg)
23
About Some Sensors
Wheel EncodersActive Ranging
![Page 24: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/24.jpg)
24
Wheel Encoders
![Page 25: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/25.jpg)
25
Wheel/Motor Encoders (1) Principle: Photo detection + optical grid Direction of motion: Quadrature encoder Output: Read values with polling or use interrupts Resolution: 2000 (->10K) cycles per revolution (CPR).
for higher resolution: interpolation, sine waves Accuracy: no systematic error (accuracy~100%)
time
Rotating optical grid
![Page 26: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/26.jpg)
26
Wheel/Motor Encoders (2) Measures position or speed
of the wheels or steering Use: odometry,
position estimation, detect sliding of motors
scanning reticle fields
scale slits
Direction change:
![Page 27: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/27.jpg)
27
Active Range Sensors
![Page 28: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/28.jpg)
28
Range Sensors Large range distance measurement
-> “range sensors” Why?
Range information is key for localization and environment modeling
Cheap Relatively accurate
How? Time of flight Active sensing (sound, light)
![Page 29: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/29.jpg)
29
Time of flight - principles Time delay of arrival (TDOA)
TDOA – impulses Sound, light
TDOA – phase shift Light
Geometry Triangulation – single light beam
Light Triangulation – structured light
Light Light sensor; 1D or 2D camera
![Page 30: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/30.jpg)
30
Time Delay of Arrival
d = v t d – distance travelled (computed) v – speed of propagation (known) t – time of flight (measured)
2D = v t
D
TargetSource & sensor
![Page 31: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/31.jpg)
31
TDOA: Limitations What distances can we measure?
Must wait for the last package to arrive before sending out the next one=> Speed of propagation determines maximum range!
Speeds Sound: 0.3 m/ms Electromagnetic signals (light=laser):
0.3 m/ns, 1M times faster! 3 meters takes..
Sound: 10 ms Light: 10 ns
.. But technical difficulties => expensive and delicate sensors
![Page 32: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/32.jpg)
32
TDOA: Errors Time measurement
Exact time of arrival of the reflected signal Time of flight measure (laser range sensors)
Opening angle of transmitted beam (ultrasonic range sensors)
Interaction with the target (surface, specular reflections)
Variation of propagation speed Speed of mobile robot and target (if not at
stand still)
![Page 33: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/33.jpg)
33
Ultrasonic Sensor
![Page 34: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/34.jpg)
34
Ultrasonic (US) Sensor transmit a packet of US pressure waves The speed of sound v (340 m/s) in air is
°: adiabatic index (sound wave->compression->heat)
R: moral gas constant [J/(mol K)] M: molar mass [kg/mol] T: temperature [K]
v =q
° RM T
![Page 35: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/35.jpg)
35
Operation
Transmitted sound
Analog echo signal &
threshold
Digital echo signal
Integrated time & output signal
integrator Time of flight (output)
threshold
Wave packet
Blanking time
![Page 36: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/36.jpg)
36
Ultrasonic Sensor Frequencies: 40 - 180 kHz Sound source: piezo/electrostatic transducer
transmitter and receiver separated or not separated Propagation: cone
opening angles around 20 to 40 degrees regions of constant depth segments of an arc (sphere for 3D)
Typical intensity distribution of an ultrasonic sensor
-30°
-60°
0°
30°
60°
Amplitude [dB]
measurement cone
Piezo transducer
Electrostatic transducer
![Page 37: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/37.jpg)
37
Example
![Page 38: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/38.jpg)
38
Imaging with an USIssues: Soft surfaces Sound surfaces that are far from being
perpendicular to the direction of the sound -> specular reflection
a) 360° scan b) results from different geometric primitives
![Page 39: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/39.jpg)
39
Characteristics
Range: 12cm – 5 m Accuracy: 98%-99.1% Single sensor operating speed: 50Hz
3m -> 20ms ->50 measurements per sec Multiple sensors:
Cycle time->0.4sec -> 2.5Hz->limits speed of motion (collisions)
![Page 40: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/40.jpg)
40
Laser Range Sensor
![Page 41: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/41.jpg)
41
Laser Range Sensor: Physics
Laser=•Low divergence•Well-defined wavelength
![Page 42: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/42.jpg)
42
Time of flight measurement methods
Pulsed laser Direct measurement of elapsed time Receiver: Picoseconds accuracy Accuracy: centimeters
Beat frequency between a frequency modulated continuous wave and its received reflection
Phase shift measurement Technically easier than the above two
methods
![Page 43: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/43.jpg)
43
Distance from phase-shift
¸
z
Phase [m]
Transmittedbeam (s(x))
Reflected beam (r(x))
Target
d
r(x) = s(2d¡ x)
r(z) = 0 , s(2d¡ z) = 0, 2d¡ z = k¸ , z = 2d+ k0̧
sinced < ¸=2;k0= 0) z = 2d ) µ= 2¼2d¸
d= µ¸4¼
Amplitude [V]
Ambiguity! d and d+¸/2 give the same µAmbiguity! d and d+¸/2 give the same µ
![Page 44: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/44.jpg)
44
Laser Range Sensor Phase-Shift Measurement
c: speed of light (0.3 m/ns)
f: the modulating frequency
D’: distance covered by the emitted light
for f = 5 Mhz (as in the AT&T sensor), = 60 meters
PhaseMeasurement
Target
D
L
Transmitter
Transmitted BeamReflected Beam
P
2
2 LDLD = c/f
![Page 45: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/45.jpg)
45
Laser Range Sensor
Confidence in the range (phase estimate) is inversely proportional to the square of the received signal amplitude. Hence dark, distant objects will not produce such good range estimated as closer brighter objects …
![Page 46: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/46.jpg)
46
Laser Range Sensor Typical range image of a 2D laser range sensor with a rotating mirror. The length
of the lines through the measurement points indicate the uncertainties.
![Page 47: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/47.jpg)
47
Triangulation Ranging Geometry -> distance
Unknown object size: project a known light pattern onto the environment and use triangulation
Known object size: triangulation without light projecting
![Page 48: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/48.jpg)
48
Laser Triangulation (1D)
Target
D
L
Laser / Collimated beam
Transmitted Beam
Reflected Beam
P
Position-Sensitive Device (PSD)
or Linear Camera
x
Lens
x
LfD
![Page 49: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/49.jpg)
49
Sharp IR Rangers
![Page 50: 1 CMPUT 412 Sensing Csaba Szepesvári University of Alberta TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AA A A A A](https://reader031.vdocument.in/reader031/viewer/2022013004/56649d2a5503460f949feb41/html5/thumbnails/50.jpg)
50
Conclusions
Why & how? Sensing: Essential to deal with
contingencies in the world Sensors: Make sensing possible
Anatomy of sensors: Physics, A/D, characteristics
Wheel encoders Distance sensors
Time of flight Triangulation