Generating LiDAR data in laboratory: g y LiDAR Simulator Bharat - - PowerPoint PPT Presentation

Generating LiDAR data in laboratory: g y LiDAR Simulator

Bharat Lohani, R K Mishra Department of Civil Engineering Department of Civil Engineering Indian Institute of Technology Kanpur Kanpur INDIA

M i i Motivation…

Are LiDAR data available ?

LiDAR data NOT available in majority of LiDAR data NOT available in majority of

countries

Lack of awareness Lack of awareness Security issues Cost

Bharat Lohani, IIT Kanpur India

Are LiDAR data available ?

LiDAR data NOT available for teaching LiDAR data NOT available for teaching

purposes

Readily available data Readily available data Data with as-desired specifications Data with ground truth

g

Bharat Lohani, IIT Kanpur India

Are LiDAR data available ?

LiDAR data NOT available for research LiDAR data NOT available for research

Data with a wide range of desired specifications Data with complete and 100% accurate ground Data with complete and 100% accurate ground

truth

Bharat Lohani, IIT Kanpur India

Solution lies in LiDAR simulator…

User creates a terrain User creates a terrain User chooses the flight parameters

LiDAR data are generated for created

LiDAR data are generated for created

terrain as if the actual LiDAR sensor had flown the terrain flown the terrain

Bharat Lohani, IIT Kanpur India

Design consideration for Design consideration for simulator

Should be . . .

User friendly User friendly Wider distribution Help or tutorial

Bharat Lohani, IIT Kanpur India

Can simulate . . .

Generic sensor Specific sensors Specific sensors

ALTM ALS And others…

Bharat Lohani, IIT Kanpur India

Should simulate trajectory as in a normal flight

6 degrees of freedom

6 degrees of freedom

Bharat Lohani, IIT Kanpur India

Should simulate earthlike surfaces

Source: Optech Inc.

Bharat Lohani, IIT Kanpur India

Also…

Possibility of error introduction Possibility of error introduction Output data available in common formats

Bharat Lohani, IIT Kanpur India

Development of simulator Development of simulator

System components

Integration

Sensor component T i Trajectory Terrain component

Out put

Input

Trajectory component

Bharat Lohani, IIT Kanpur India

T j t p t Trajectory component

Flight direction Location Attitude

Location

Location: coordinates of laser head at each

firing of pulse

Location depends on Instantaneous

accelerations accelerations

Instantaneous accelerations should be

simulated as in a normal flight: pseudo- random simulation

Bharat Lohani, IIT Kanpur India

Acceleration simulation

2 2 sin ( ( )) cos ( ( )) ( )

J K i X j j t k k t t

a A B id C D id m id T T π π ⎛ ⎞ ⎛ ⎞ = + + ⎜ ⎟ ⎜ ⎟ ⎝ ⎠ ⎝ ⎠

∑ ∑

1 1 X j j t k k t t j k

T T

= =

⎜ ⎟ ⎜ ⎟ ⎝ ⎠ ⎝ ⎠

∑ ∑

F = Firing frequency J,K,A,B,C,D and m governing parameters parameters

Bharat Lohani, IIT Kanpur India

Location simulation

1 2

1 2

i i i i x t x t

X X u d a d

+ =

+ + 2

X

V l it i di ti fli ht i X i ux = Velocity in direction flight i.e. X axis

Bharat Lohani, IIT Kanpur India

Attitude (Roll, Pitch, Yaw) simulation

2 2 sin ( ( )) cos ( ( )) ( )

J K i j j t k k t t

R A B id C D id m id T T π π ⎛ ⎞ ⎛ ⎞ = + + ⎜ ⎟ ⎜ ⎟ ⎝ ⎠ ⎝ ⎠

∑ ∑

1 1 j j t k k t t j k

T T

= =

⎜ ⎟ ⎜ ⎟ ⎝ ⎠ ⎝ ⎠

∑ ∑

Bharat Lohani, IIT Kanpur India

Sensor components Sensor components

Sinusoidal scan pattern p Zig-zag scan pattern

Sinusoidal scan pattern p

Let time taken to complete 1/4th of a scan is T. P is the numbers of points in 1/4th of a scan.

( )

p The maximum scan angle is өmax.

1

( )

max 2

sin where

i i T T i i

t t

π

θ θ =

0.5 Z (m)

where, i

i P

t

=

160 140 160

• 1
• 0.5

60 80 100 120 140 160 80 100 120 140 X (m) Y (m)

Bharat Lohani, IIT Kanpur India

Zig-zag scan pattern g g p

θ max i P i θ

θ =

1 0.5 Z (m) 140 160

• 1
• 0.5

60 80 100 120 140 80 100 120 140 X (m) Y (m)

Bharat Lohani, IIT Kanpur India

Terrain component Terrain component

Modeling surfaces: earthlike

Vector approach: mathematical surfaces Raster approach with over ground objects Fractal terrain

Vector approach: Mathematical surfaces pp

Simple Surface Simple Surface

• AX+BY+CZ+D=0

Example of a simple surface: 2X+5Y+10Z-100=0 (displayed in surfer)

Bharat Lohani, IIT Kanpur India

Vector approach: Mathematical surfaces pp

Complex Surface p

• Z=A[sin(X/B)+sin(XY/BC)]+D

Example of a complex surface: z=10[sin(X/25)+sin(XY/(25*50)]-300 (displayed in surfer)

Bharat Lohani, IIT Kanpur India

Raster surfaces

Bharat Lohani, IIT Kanpur India

Fractal surfaces

Bharat Lohani, IIT Kanpur India

Integration of components Integration of components

Integration of components

i i i

X X Y Y Z Z

i i i i i i

X X Y Y Z Z a b c − − − = =

Bharat Lohani, IIT Kanpur India

Error introduction in simulated data

2

( )

i i

X X N μ σ = + ( , )

T t X X

X X N μ σ = +

Bharat Lohani, IIT Kanpur India

Concept implementation Concept implementation

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Optimal flight lines given by system p g g y y

Bharat Lohani, IIT Kanpur India

User defined flight lines g

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Simulated data and results Simulated data and results

3D raster terrain (displayed in f )

Altitude=210m

Overlap=4% Velocity=60m/s

surfer)

Sensor-ALS-50 Firing frequency=20KHz Scan frequency=48Hz Scan angle=40° Flight area=430m 430m Bharat Lohani, IIT Kanpur India

LiDAR data plot in plan

A-A B-B

Bharat Lohani, IIT Kanpur India

Profile A-A without error Profile A-A with error

Bharat Lohani, IIT Kanpur India

Profile B-B w. r. t. flight lines g

Bharat Lohani, IIT Kanpur India

LiDAR data without error

Bharat Lohani, IIT Kanpur India

LiDAR data with error

Bharat Lohani, IIT Kanpur India

Data with no attitude variation

Bharat Lohani, IIT Kanpur India

Data with attitude variation

Bharat Lohani, IIT Kanpur India

Fractal data displayed in surfer

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Terrain with objects

Bharat Lohani, IIT Kanpur India

LiDAR data of terrain with objects

Altitude=490m

Overlap=2% Velocity=60m/s Sensor-ALS-50 Firing frequency=20KHz Scan frequency=48Hz Scan angle=50° Flight area=640m×460m Bharat Lohani, IIT Kanpur India

Altitude=400m

Overlap=2% Velocity=60m/s Sensor-ALS-50

Effect of data density

Firing frequency=20KHz Scan frequency=48Hz Scan angle=50° Bharat Lohani, IIT Kanpur India

Altitude=400m

Overlap=2% Velocity=60m/s Sensor-ALS-50 Firing frequency=5 KHz Scan frequency=48Hz Scan angle=50° Bharat Lohani, IIT Kanpur India

1 2

Profile view of buildings

2

Profile view-1 Profile view-2

Bharat Lohani, IIT Kanpur India

Effect of different altitude

Altitude=200m

Overlap=2% Velocity=60m/s Sensor-ALS-50 Sensor-ALS-50 Firing frequency=5 KHz Scan frequency=48Hz Scan angle=50° Bharat Lohani, IIT Kanpur India

Altitude=100m

Overlap=2% Velocity=60m/s Sensor-ALS-50 Sensor-ALS-50 Firing frequency=5 KHz Scan frequency=48Hz Scan angle=50° Bharat Lohani, IIT Kanpur India

Effect of different scan angle

Altitude=200m

Overlap=2% Velocity=60m/s Sensor-ALS-50 Sensor-ALS-50 Firing frequency=5 KHz Scan frequency=48Hz Scan angle=50° Bharat Lohani, IIT Kanpur India

Altitude=200m Altitude=200m

Overlap=2% Velocity=60m/s Sensor-ALS-50 Firing frequency=5 Scan angle=32 Firing frequency 5 KHz Scan frequency=48Hz Scan angle=32° Bharat Lohani, IIT Kanpur India

Effect of different flight direction

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Applications of simulator Applications of simulator

Education

To understand:

Process of data generation Effect of change in various parameters on

data

Effect of errors on data

Bharat Lohani, IIT Kanpur India

Laboratory exercises

Data with varied specifications Data with varied specifications

Full and accurate ground truth known

Full and accurate ground truth known

Bharat Lohani, IIT Kanpur India

Research projects

Evaluation of Information extraction

algorithms g

Assessing effect of error on performance of

g algorithms

Finding optimal data specifications for an

application

Bharat Lohani, IIT Kanpur India

Application in building identification research

Bharat Lohani, IIT Kanpur India

Variation of accuracy indices

Bharat Lohani, IIT Kanpur India

Variation of accuracy indices

Bharat Lohani, IIT Kanpur India

Final touches…in next three months

Multiple return implementation Multiple return implementation

Error introduction in individual parameters

Error introduction in individual parameters

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

Bharat Lohani, IIT Kanpur India

) ( )) ( 2 ( cos )) ( 2 ( sin

t t k K k t j J j i X

id m id D C id B A a + ⎟ ⎞ ⎜ ⎛ ∏ + ⎟ ⎞ ⎜ ⎛ ∏ =

∑ ∑

j=2, k=2

) ( )) ( ( cos )) ( ( sin

1 1 t t k k k t j j j X

id m id T D C id T B A a + ⎟ ⎠ ⎜ ⎝ + ⎟ ⎠ ⎜ ⎝

∑ ∑

= =

0.38

B1

1.65

A2

3.54

A1

0.51

C1

2.45

B2

1

0.88

D2

2.77

D1

3.77

C2

1000

T

0.001

dt

0.0

m

1000

T Bharat Lohani, IIT Kanpur India

) ( )) ( 2 ( cos )) ( 2 ( sin

t t k K k t j J j i X

id m id D C id B A a + ⎟ ⎞ ⎜ ⎛ ∏ + ⎟ ⎞ ⎜ ⎛ ∏ =

∑ ∑

j=2, k=2

) ( )) ( ( cos )) ( ( sin

1 1 t t k k k t j j j X

id m id T D C id T B A a + ⎟ ⎠ ⎜ ⎝ + ⎟ ⎠ ⎜ ⎝

∑ ∑

= =

3.38

B1

3.25

A2

0.68

A1

0.89

C1

4.45

B2

1

1.34

D2

5.23

D1

2.54

C2

1000

T

0.001

dt

0.0

m

1000

T Bharat Lohani, IIT Kanpur India

) ( )) ( 2 ( cos )) ( 2 ( sin

t t k K k t j J j i X

id m id D C id B A a + ⎟ ⎞ ⎜ ⎛ ∏ + ⎟ ⎞ ⎜ ⎛ ∏ =

∑ ∑

j=2, k=2

) ( )) ( ( cos )) ( ( sin

1 1 t t k k k t j j j X

id m id T D C id T B A a + ⎟ ⎠ ⎜ ⎝ + ⎟ ⎠ ⎜ ⎝

∑ ∑

= =

4.38

B1

0.25

A2

1.78

A1

1.78

C1

2.45

B2

1

2.34

D2

3.23

D1

1.24

C2

1000

T

0.001

dt

0.003

m

1000

T Bharat Lohani, IIT Kanpur India

) ( )) ( 2 ( cos )) ( 2 ( sin

t t k K k t j J j i X

id m id D C id B A a + ⎟ ⎞ ⎜ ⎛ ∏ + ⎟ ⎞ ⎜ ⎛ ∏ =

∑ ∑

j=2, k=2

) ( )) ( ( cos )) ( ( sin

1 1 t t k k k t j j j X

id m id T D C id T B A a + ⎟ ⎠ ⎜ ⎝ + ⎟ ⎠ ⎜ ⎝

∑ ∑

= =

4.38

B1

0.25

A2

1.0

A1

0.78

C1

5.45

B2

1

4.34

D2

7.23

D1

1.24

C2

1000

T

0.001

dt

0.004

m

1000

T Bharat Lohani, IIT Kanpur India

j=3, k=3

) ( )) ( 2 ( cos )) ( 2 ( sin

t t k K k t j J j i X

id m id D C id B A a + ⎟ ⎞ ⎜ ⎛ ∏ + ⎟ ⎞ ⎜ ⎛ ∏ =

∑ ∑

0.65 A2 2.75 A1

) ( )) ( ( cos )) ( ( sin

1 1 t t k k k t j j j X

id m id T D C id T B A a + ⎟ ⎠ ⎜ ⎝ + ⎟ ⎠ ⎜ ⎝

∑ ∑

= =

B2 4.45 B1 2.38 A3 0.6 C 1 77 C1 B3 1.51 80 D1 C3 2.77 C2 1.77 0.35 m D3 D2 0.0 3.38 100 T dt 1000 0.006

Bharat Lohani, IIT Kanpur India

Comparison of data sets without RPY and with Roll only.

Equation of the surface: Z=sin(X/10)-sin(XY/90)-60. Flight velocity: 60 m/s. Flight height: 60 m. Distance: 30 m. Firing frequency: 5000 Hz. Scan frequency: 48 Hz

a d t

• o y

Scan frequency: 48 Hz. Scan angle: 50 deg.

Bharat Lohani, IIT Kanpur India

Comparison of data sets without RPY and with Pitch only

Equation of the surface: Z=sin(X/10)-sin(XY/90)-60. Flight velocity: 60 m/s. Flight height: 60 m. Distance: 30 m. Firing frequency: 5000 Hz. Scan frequency: 48 Hz. Scan angle: 50 deg.

Bharat Lohani, IIT Kanpur India

Comparison of data sets without RPY and with Yaw only

Equation of the surface: Z=sin(X/10)-sin(XY/90)-60. Flight velocity: 60 m/s. Flight height: 60 m. Distance: 30 m. Firing frequency: 5000 Hz. Scan frequency: 48 Hz. Scan angle: 50 deg.

Bharat Lohani, IIT Kanpur India

Comparison of data sets with and without RPY

Equation of the surface: Z=sin(X/10)-sin(XY/90)-60. Flight velocity: 60 m/s. Flight height: 60 m. Distance: 30 m. Firing frequency: 5000 Hz. Scan frequency: 48 Hz. Scan angle: 50 deg Scan angle: 50 deg.

Bharat Lohani, IIT Kanpur India

Comparison of data sets with lower and higher ax

Eq ation of the s rface AX+B +CZ+D 0 Equation of the surface: AX+By+CZ+D=0. (A=0, B=0, C=0, D= -65) Flight velocity: 60 m/s. Flight height: 65 m. Distance: 60 m. Firing frequency: 5000 Hz. Scan frequency: 48 Hz. Scan frequency: 48 Hz. Scan angle: 50 deg.

Bharat Lohani, IIT Kanpur India

LiDAR data of fractal terrain

Altitude=500m

Overlap=2% Velocity=60m/s Sensor-ALS-50 Firing frequency=20KHz Scan frequency=48Hz Scan angle=50° Flight area=550×550km

A-A

Bharat Lohani, IIT Kanpur India

Profile A-A P fil B B Profile B-B

Bharat Lohani, IIT Kanpur India