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Self-Calibrating Imaging Polarimetry Self-Calibrating Imaging Polarimetry

Self-Calibrating Imaging Polarimetry - PowerPoint Presentation

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Self-Calibrating Imaging Polarimetry - PPT Presentation

1 camera polarizer analyzer protractor lens Yoav Y Schechner EE Technion Israel S elfcalibration in other imaging problems Y Schechner selfcalibrating polarimetry ID: 788408

polarimetry schechner camera calibrating schechner polarimetry calibrating camera polarizer min arg 180 120 imaging true calibration polarization unknown result

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Slide1

Self-Calibrating Imaging Polarimetry

1

camera

polarizer (analyzer)

protractor

lens

Yoav Y.

Schechner

EE, Technion , Israel

Slide2

Self-calibration

in other imaging problems

Y. Schechner,

self-calibrating polarimetry

2

Slide3

Self-calibration of radiometric properties

spatial non-uniformity

pixel

electronic readout

light intensity

A. Litvinov & Y. Schechner,

radiometric nonidealities

Spatial non-uniformity Time-varying gain

Response

nonlinearity

3

Debevec

; Malik (98)

Mitsunaga

;

Nayar

(99)

Kim;

Pollefeys

(04)

Schechner

;

Nayar

(01)

Slide4

Structure from Motion (

SfM

)

 

 

 

4

 

 

Unknown

 

Unknown

 

Schechner

Slide5

Polarization

Y

. Schechner, self-calibrating polarimetry

5

Slide6

Tedious,

inaccurate control

N. Karpel

& Y. Schechner, underwater imaging

protractor

polarizer

6

Slide7

polarizer

180

o

3 general measurements

suffice,

a

t

known orientations

Polarization

vector

determination

camera

Y

.

Schechner

,

self-calibrating polarimetry

7

Slide8

polarizer

180

o

What about

unknown

orientations

?

Polarization

vector

determination

camera

Y

.

Schechner

,

self-calibrating polarimetry

8

Slide9

9

Self-calibration would allow

Easy polarimetry-based methods, by lay person

(SLR? Smartphone?)Scientific exploration by the lay person

Less hassle for experimentalists (lab and field)Increase tolerance in scientific-grade specsBiological understanding

Y

.

Schechner

,

self-calibrating polarimetry

Slide10

10

Y

.

Schechner

, self-calibrating polarimetry

camera

 

 

 

 

 

 

 

Slide11

 

 

 

 

11

Y

.

Schechner

,

self-calibrating polarimetry

camera

polarizer

 

 

 

 

Slide12

 

 

 

 

12

Y

.

Schechner

,

self-calibrating polarimetry

camera

polarizer

 

 

 

 

 

 

Slide13

13

 

Y

.

Schechner

,

self-calibrating polarimetry

Slide14

14

 

 

 

 

 

 

 

 

 

 

 

 

2

=

Y

.

Schechner

,

self-calibrating polarimetry

Slide15

15

 

 

 

 

 

 

 

 

 

 

 

 

2

 

=

Y

.

Schechner

,

self-calibrating polarimetry

Slide16

16

 

 

 

 

 

 

 

 

 

 

 

 

2

P

 

=

Y

.

Schechner

,

self-calibrating polarimetry

Slide17

17

 

 

 

 

 

 

 

 

2

P

=

Y

.

Schechner

,

self-calibrating polarimetry

Slide18

18

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

P

 

 

 

 

 

 

 

 

=

Y

.

Schechner

,

self-calibrating polarimetry

Slide19

19

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

P

 

 

 

 

 

 

 

 

D

 

=

Y

.

Schechner

,

self-calibrating polarimetry

Slide20

20

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

P

 

 

 

 

 

 

 

 

 

O

D

 

=

Y

.

Schechner

,

self-calibrating polarimetry

Slide21

21

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

P

 

 

 

 

 

 

 

 

O

D

 

 

=

 

Y

.

Schechner

,

self-calibrating polarimetry

Slide22

Y

.

Schechner

, self-calibrating polarimetry

22

D

=

P

O

 

 

 

At least 3 object points and 4 images

At least 2 object points and 5 images

Slide23

23

D

=

P

O

arg

min ||

D

-

P

O

||

 

 

 

 

P

Y

.

Schechner

,

self-calibrating polarimetry

Slide24

24

arg

min ||

D

-

P

O

||

 

 

 

 

P

 

 

 

 

O

,

Y

.

Schechner

,

self-calibrating polarimetry

Slide25

25

Given

P

(standard polarimetry)

O

=

arg

min ||

D

-

P

O

||

O

Y

.

Schechner

,

self-calibrating polarimetry

Slide26

26

 

 

 

 

P

arg

min ||

D

-

P

O

||

 

 

 

 

O

,

Y

.

Schechner

,

self-calibrating polarimetry

Slide27

27

arg

min ||

D

-

P

O

||

~

P

T

 

 

 

~

P

T

Given

O

Y

.

Schechner

,

self-calibrating polarimetry

Slide28

28

arg

min ||

-

||

~

P

T

~

P

Given

O

T

~

O

T

~

D

r

Result:

T

~

P

Y

.

Schechner

,

self-calibrating polarimetry

Slide29

Y

. Schechner

, self-calibrating polarimetry

29

~

P

T

 

 

 

Result:

T

~

P

 

 

 

Slide30

30

 

 

 

Result:

T

~

P

 

 

 

Normalize rows

Y

.

Schechner

,

self-calibrating polarimetry

Slide31

Y

.

Schechner

, self-calibrating polarimetry

31

Roughly guessed

O

=

arg

min ||

D

-

P

O

||

O

=

arg

min ||

-

||

~

P

T

~

P

T

~

O

T

~

D

r

T

~

P

Angle estimates

Slide32

camera

lens

polarizer (analyzer)

rotating mountTripod-head

camera

polarizer (analyzer)

rotating

mount

protractor

lens

32

 

Y

.

Schechner

,

self-calibrating polarimetry

Slide33

33

Y

.

Schechner,

self-calibrating polarimetry

Slide34

34

45

135

0

90

170

20

110

50

80

140

200

hundred iterations

 

 

 

 

 

true

 

 

 

 

 

 

 

 

 

 

 

first guess

 

Y

.

Schechner

,

self-calibrating polarimetry

Slide35

35

30

60

90

120

150

0

180

30

60

90

120

0.2

0.2

0.4

0.4

0.6

0.6

0.8

0.8

0

Y

.

Schechner

,

self-calibrating polarimetry

Slide36

36

Y

.

Schechner,

self-calibrating polarimetry

Slide37

45

60

90

135

180

0

150

30

90

120

45

135

180

0

90

20

110

50

80

140

200

Y

.

Schechner

,

self-calibrating polarimetry

37

hundred iterations

 

 

 

 

 

true

 

 

 

 

 

 

 

 

 

 

 

first guess

 

Slide38

38

30

60

90

120

150

0

180

30

60

90

120

0.2

0.2

0.4

0.4

0.6

0.6

0.8

0.8

0

Y

.

Schechner

,

self-calibrating polarimetry

Slide39

||

D

-

P

O ||

2

||

D

-

P

O

||

2

e

=

true

true

39

iteration

10

100

1

10

100

1,000

1

Schechner

Slide40

40

Code available online:

webee.technion.ac.il

/~yoav/research/polar-self-calib

Y. Schechner

, self-calibrating polarimetry

Polarimetric

imaging has a

self-calibration capacity !!