optical design for automatic identification and portable

Optical Designfor Auto ID

and PortableSystems

Luisa DeMarco

IntroductionResearch aim

Research results

ImagingSystemSAFARILAB

OLOM

SLALOM

Non ImagingSystemFreeform lens designtool

Pattern generatordesign tool

Conclusions

Optical Design forAutomatic Identificationand Portable Systems

Luisa De Marcotutors: Prof. Paolo Bassi, eng. Federico Caninicotutors: eng. Marco Gnan, eng. Bassam Hallal

25 January 2012


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

Outline

1 IntroductionResearch aimResearch results

2 Imaging SystemSAFARILABOLOM

SLALOM

3 Non Imaging SystemFreeform lens design toolPattern generator design tool

4 Conclusions


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

Research aim

Research aim: new Optical Design Techniquesto improve Auto ID and Portable systems Performance

Possible applications:

Optical systems to be designed of a Barcode Reader, i.e.:


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

Research results

Imaging SystemsCharacterization tool (SAFARILAB)

to measure the system Spatial Frequency Response, SFR

Optical Level Optimization tool (OLOM)

to optimize the optical part of the imaging system (lens)

System Level Analysis and Optimization tool (SLALOM)

to analyze and optimize the whole imaging system (lens, electronics, detector)

Non Imaging SystemsFreeform lens design tool to optimize a freeform lens

that used with a LED produces a custom illumination

Pattern generator design tool to optimize a diffractive optics that used with a LASER produces the desired pattern


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

Outline



SLALOM


4 Conclusions


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

SAFARILAB

Imaging System characterization: Spatial FrequencyResponse measurement (SFR = F [PSF])

Edge Source: Slanted edge to avoid sampling effect(dependency on pixel array alignment wrt the edge)


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

SAFARILAB

Software:

calculates SFR from a slanted edge imagefollows the ISO 12233 standardreduces the noise that affects the measurement

Measurement set up:


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

SAFARILAB

SaFaRiLAB vs Imatest and ImageJ:

SaFaRiLAB: comparable with other available softwares


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

SAFARILAB

Noise reduction:

0 0.5 1 1.5 2

0

0.2

0.4

0.6

0.8

1

Normalized spatial frequency

SF

R

Strong reduction of noise that affects the measurement


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

OLOM

Optical Level Optimization (OLOM) tool: able to optimizeat Optical Level (just lens) an imaging system with SFRinvariance as Cubic Phase Mask (CPM) System

SFR



and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

OLOM

Optical imaging system design (in ZEMAX):already designed lensoptimization of α in cubic phase mask using OLOM

(CPM = f (x , y) = α(x3 + y3))

STOPC

PM

CCD

SENSOR

STOP

ORIGINAL LENS


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

OLOM

Performance design evaluation:minimum resolving power [Mils]

0 0.25 0.5 0.75 10

0.25

0.5

0.75

1


SFR

threshold (th)

frequency limit (fth)

R =minimum resolutionM = magnification


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

OLOM

Performance without CPM vs with CPM andMEASURED vs DESIGNED:

the CPM extends the Depth Of Field (DoF);measured and designed results are comparable.

0 200 400 600 800 1000 1200 1400

13 mils

20 mils

40 mils

Object Distance [mm]

826886

386392

443445

227234

284292

168178

NOCPM−DESIGNEDNOCPM−MEASUREDCPM−DESIGNEDCPM−MEASURED


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

SLALOM

System Level Analysis and Optimization (SLALOM) tool:able to optimize and analyze at System Level (lens,electronics decoder) an imaging system with SFRinvariance


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

SLALOM

System Level Analysis and Optimization (SLALOM) tool:(a) O-SLALOM, (b) A-SLALOM


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

SLALOM

Optical imaging system design (in ZEMAX):Two possible design for adding a quartic contribution toan original lens:First Design : change of a surface of the original lensSecond Design : addition of a lens with a quartic

surfacestarting design optimized by OLOM

optimization of the quartic surface using SLALOM

STOP

CCD

SENSOR

STOP

ORIGINAL LENSSecondDesign

FirstDesign


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

SLALOM

First Design: before and after using SLALOM

DEC

FAIL


DEC

FAIL


Second Design: before and after using SLALOM

DEC

FAIL


DEC

FAIL



and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

Outline



SLALOM


4 Conclusions


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

Freeform lens design tool

Freeform lens design for a Custom Illumination:limited into a desired area and with more light along thearea edges (compensation for sensor light losses)implementation (in MATLAB) of a software foroptimization of the free-form lens coefficients

z = f (x , y) = c1x2 + c2y2 + c3x4 + c4x2y2 + c5y4 · · ·+ c6x6 + c7x4y2 + c8x2y4 + c9y6


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions


Surface measurement of the lens Free-Form prototype:

Good agreement between measured and designedsurface


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions


Irradiance profile measurement:

Good agreement between irradiance profile of free-formlens DESIGNED and MEASURED


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

Pattern generator design tool*

Problem:to design a Diffractive Optical Element, DOE that with aLASER produces a large Field Of View, FoV (not paraxialhypothesis).

Image

DOE

LASER

FOV= 40°

* developed at Friedrich-Alexander University, Erlangen, DE


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

Pattern generator design tool

Starting point:Iterative Fourier Transform Algorithm (IFTA) that assumesparaxial approximation.

Y @D

Y

AmplitudeConstraint:

DOE*(CGH plane)

Projection(image plane)

DOE(CGH plane)

Projection*(image plane)

AmplitudeConstraint:

),(*yxF νν

),( yxF νν

))arg(exp(* fjf = ))arg(exp(||* FjFF des=

),(* yxf

),( yxf


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions


Solution:predistortion of desired image considering the effectscaused by non paraxial angle assumption.

blue line: desired image (little square at 20◦, big squareat 40◦);red line: predistorted desired image

−0.4 −0.3 −0.2 −0.1 0 0.1 0.2 0.3 0.4−0.4

−0.3

−0.2

−0.1

0

0.1

0.2

0.3

0.4


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions


Patterns generated by DOEs designed with and withoutParaxial Approximation Compensation:


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions


FoV measurement:

100 200 300 400 500-300

-200

-100

0

100

200

300

z[mm]

x[m

m]

21.2° 21.4°

41.4° 45.2°

CPA PA

20°

40°

SPEC


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

Outline



SLALOM


4 Conclusions


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

Conclusions

Imaging SystemsCharacterization tool (SAFARILAB)

able to measure imaging systems performance

Optical Level Optimization tool (OLOM)

provides a starting point optical design for the whole system optimization

System Level Analysis and Optimization tool (SLALOM)

provides a whole optimized system

Non Imaging SystemsFreeform lens design tool freeform lens optimized to

obtained the desired illumination

Pattern generator design tool DOE optimized to obtained the desired pattern


and PortableSystems

Luisa DeMarco


Research results


OLOM

SLALOM



Conclusions

THANKS FOR YOUR

ATTENTION!

optical design for automatic identification and portable

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