the future of nvis display measurement ali advanced seminar, 2006optronic laboratories dr. richard...

The Future of NVIS Display Measurement The Future of NVIS Display Measurement The Future of NVIS Display Measurement The Future of NVIS Display Measurement

ALI Advanced Seminar, 2006ALI Advanced Seminar, 2006 Optronic LaboratoriesOptronic LaboratoriesALI Advanced Seminar, 2006ALI Advanced Seminar, 2006 Optronic LaboratoriesOptronic Laboratories

The Future of NVIS Display The Future of NVIS Display MeasurementMeasurement

Dr. Richard Young

Optronic Laboratories, Inc.



IntroductionIntroduction

Thanks to the excellent quality of modern scanning instruments, NVIS compatibility

measurements have become almost routine.

What improvements could instrument manufacturers make…



IntroductionIntroduction

• Better sensitivity, so low luminance small spot sizes can be measured as easily as high luminance large spot sizes.

• Less variation in results

• Faster scans

• Greater portability and ruggedness

• Lower cost

A wish-list for improvements…



Sensitivity and VariabilitySensitivity and VariabilityAn Example of OL 750S-NVG performance vs MIL sensitivity specification

1.0E-15

1.0E-14

1.0E-13

1.0E-12

1.0E-11

1.0E-10

1.0E-09

350 400 450 500 550 600 650 700 750 800 850 900 950

Wavlength [nm]

Rad

ian

ce @

10:

1 S

/N [

W/(

cm²

nm

sr)

]

0.18mm spot size

0.3mm spot size

0.6mm spot size

1.8mm spot size

3.0mm spot size

MIL specification

Much of the Much of the variability is variability is due to the due to the

longer longer wavelengthswavelengths

Much of the Much of the variability is variability is due to the due to the

longer longer wavelengthswavelengths

Scanning systems have Scanning systems have plenty of sensitivityplenty of sensitivity

Scanning systems have Scanning systems have plenty of sensitivityplenty of sensitivity



Sensitivity and VariabilitySensitivity and VariabilityOL 750S-NVG and OL 770-NVS performance vs MIL sensitivity specification

1.0E-15

1.0E-14

1.0E-13

1.0E-12

1.0E-11

1.0E-10

1.0E-09

350 400 450 500 550 600 650 700 750 800 850 900 950

Wavlength [nm]

Rad

ian

ce @

10:

1 S

/N [

W/(

cm²

nm

sr)

]

0.18mm spot size0.3mm spot size0.6mm spot size1.8mm spot size3.0mm spot sizeOL 770-NVS @ 0.17mm spot sizeMIL specification

There is no There is no dramatic dramatic change in change in

longer longer wavelength wavelength sensitivitysensitivity

There is no There is no dramatic dramatic change in change in

longer longer wavelength wavelength sensitivitysensitivity

The OL 770-NVS detector is based on The OL 770-NVS detector is based on silicon, and hence has a different shape,silicon, and hence has a different shape,The OL 770-NVS detector is based on The OL 770-NVS detector is based on

silicon, and hence has a different shape,silicon, and hence has a different shape,



Spectroradiometer designSpectroradiometer design

Detector

Exit Slit

Entrance Slit



Spectroradiometer designSpectroradiometer design

Detector

Exit Slit

Entrance Slit

Rotation



Spectroradiometer designSpectroradiometer designMulti-channelDetector

Entrance Slit

NO Rotation

(Each elementbehaves like adetector + slit)



The Multiplex AdvantageThe Multiplex Advantage

• When all the light is “seen” all the time:– Noise is decreased.– Sensitivity is increased.– Measurements can be faster.

The multiplex advantage means that an instrument simultaneously measuring a signal over a range of frequencies obtains a t1/2 advantage in the time t required to obtain a given signal-to-noise ratio compared to that which would be necessary using dispersive methods if the noise is detector-limited.

http://scienceworld.wolfram.com/physics/MultiplexAdvantage.html



Spectroradiometer designSpectroradiometer design• The OL 770-NVS is a special type of

spectroradiometer, many decades better than other multi-channel devices.– Far higher sensitivity– Much lower noise– Orders of magnitude lower stray light– Vastly improved electronics– Dedicated software– State-of-the-art technology



MIL Spec: OthersMIL Spec: Others• A.3.3. Wavelength accuracy & repeatability

– Accuracy typical <0.5 nm, spec. 1 nm– Repeatability typical <0.01 nm, spec. 0.5 nm

• A.3.4. Current Resolution– 16 bit, spec. 12 bit.

• A.3.5. Zero Drift– Typical <0.01%, spec. 0.2%



MIL Spec: OthersMIL Spec: Others• A.3.6. Linearity

– In scale <0.5%, spec. 1%– Between scales <0.1%, spec. 2%

• A.3.7. Signal Conditioning– Required controls for improving s/n provided

• A.3.8. Stray light– Passes easily



MIL Spec: OthersMIL Spec: Others• A.3.9. Spectroradiometer Optics

– Full scale at <0.1 fL, spec. 1 fL (at 0.007” spot size)

• A.3.10. Spectroradiometer Viewing System– Exact, spec. <5% of spot diameter

• A.3.11. Spectroradiometer Accuracy– Typically < 1%, spec. 5%– Typically u’v’ <0.0003, spec. 0.007



Other AdvantagesOther Advantages• Since there are no moving parts

– the construction is rugged and compact– results are highly repeatable– time taken in moving the monochromator,

changing filters etc. is avoided



Other AdvantagesOther Advantages• Since there is no photomultiplier

– A very expensive component is avoided– The detector is not damaged by strong light– High voltages are not required

• Since all the wavelengths are measured at the same time– It doesn’t matter if the source is d.c., a.c.,

modulated or flashed



An Intercomparison StudyAn Intercomparison Study




Green BGreen BGreen BGreen B NVIS RedNVIS RedNVIS RedNVIS RedNVIS YellowNVIS YellowNVIS YellowNVIS Yellow



An Intercomparison StudyAn Intercomparison StudySpectral Radiance of Samples

1.0E-12

1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

350 400 450 500 550 600 650 700 750 800 850 900 950

Wavelength [nm]

Sp

ec

tra

l R

adia

nc

e [

W c

m-2

nm

-1]

NVIS Green B




1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

350 400 450 500 550 600 650 700 750 800 850 900 950

Wavelength [nm]

Sp

ec

tra

l R

adia

nc

e [

W c

m-2

nm

-1]

NVIS Yellow




1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

350 400 450 500 550 600 650 700 750 800 850 900 950

Wavelength [nm]

Sp

ec

tra

l R

adia

nc

e [

W c

m-2

nm

-1]

NVIS Red




cd/m2fL NRa NRb u' v' int. time

51.32 14.98 1.46E-06 1.11E-07 0.3999 0.5398 0.4551.31 14.98 1.46E-06 1.09E-07 0.3999 0.5399 0.4551.31 14.98 1.46E-06 1.10E-07 0.3999 0.5399 0.4551.35 14.99 1.46E-06 1.08E-07 0.3999 0.5398 0.4551.32 14.98 1.46E-06 1.07E-07 0.3999 0.5398 0.4517.00 4.96 1.44E-06 1.08E-07 0.3994 0.5399 1.3217.00 4.96 1.44E-06 1.10E-07 0.3993 0.5399 1.3217.01 4.96 1.44E-06 1.09E-07 0.3993 0.5399 1.3217.01 4.96 1.44E-06 1.05E-07 0.3994 0.5400 1.3217.01 4.96 1.44E-06 1.08E-07 0.3993 0.5399 1.320.33 0.10 1.44E-06 1.07E-07 0.3992 0.5399 68.90.33 0.10 1.44E-06 1.10E-07 0.3992 0.5399 68.90.33 0.10 1.44E-06 1.11E-07 0.3993 0.5399 68.90.33 0.10 1.44E-06 1.09E-07 0.3992 0.5399 68.90.33 0.10 1.44E-06 1.06E-07 0.3992 0.5399 68.9

NVIS Red Display



NVIS Radiance for Green B display (scaled to 0.1 fL)

0.0E+00

1.0E-11

2.0E-11

3.0E-11

4.0E-11

5.0E-11

6.0E-11

7.0E-11

8.0E-11

9.0E-11

1.0E-10

1.1E-10

1.2E-10

1.3E-10

1.4E-10

1.5E-10

1.6E-10

1.7E-10

0 2 4 6 8 10 12 14 16

Luminance of Display [fL]

NV

IS R

adia

nce

[W

/(cm

² sr

)]

System 1System 2System 3

= NRa = NRb

open = day 1 solid = day 2

Spec. Max.

NVIS Green B ResultsNVIS Green B Results

For <1 For <1 second second

scanscan


scanscan

For 1-2 For 1-2 minute minute scanscan




NVIS Radiance for Green B display (scaled to 0.1 fL)

0.0E+00

1.0E-11

2.0E-11

3.0E-11

4.0E-11

5.0E-11

6.0E-11

7.0E-11

8.0E-11

9.0E-11

1.0E-10

1.1E-10

1.2E-10

1.3E-10

1.4E-10

1.5E-10

1.6E-10

1.7E-10

0 2 4 6 8 10 12 14 16


NV

IS R

adia

nce

[W

/(cm

² sr

)]


= NRa = NRb

open = day 1 solid = day 2

Spec. Max.

Scanning monochromator performance - 0.007" spot size

NVIS Green B ResultsNVIS Green B Results

For 2 For 2 minute minute scanscan

For 2 For 2 minute minute scanscan




scanscan


scanscan



NVIS Green B ResultsNVIS Green B ResultsCIE 1976 u'v' Chromaticity Diagram

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

u'

v'

Monochromatic locusGreen BYellowRedSystem 1System 2System 3

0.5774

0.5775

0.5776

0.5777

0.5778

0.5779

0.1305 0.1306 0.1307 0.1308



NVIS Red ResultsNVIS Red ResultsNVIS Radiance for Red display (scaled to 15 fL)

0.0E+00

2.0E-08

4.0E-08

6.0E-08

8.0E-08

1.0E-07

1.2E-07

1.4E-07

0 2 4 6 8 10 12 14 16


NR

b R

adia

nce

[W

/(c

m²

sr)]


Spec. Max.

Spec. Min.



NVIS Red ResultsNVIS Red ResultsCIE 1976 u'v' Chromaticity Diagram

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

u'

v'


0.5397

0.5398

0.5399

0.5400

0.3985 0.3990 0.3995 0.4000



NVIS Yellow ResultsNVIS Yellow ResultsNVIS Radiance for Yellow display (scaled to 15 fL)

0.0E+00

2.0E-08

4.0E-08

6.0E-08

8.0E-08

1.0E-07

1.2E-07

1.4E-07

0 2 4 6 8 10 12 14 16 18


NR

b R

adia

nce

[W

/(c

m²

sr)] System 1

System 2System 3

Spec. Max.

Spec. Min.



NVIS Yellow ResultsNVIS Yellow ResultsCIE 1976 u'v' Chromaticity Diagram

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

u'

v'


0.5600

0.5601

0.5602

0.5603

0.2618 0.2620 0.2622 0.2624 0.2626



Study ConclusionsStudy Conclusions• All systems gave extremely good repeatability in

NRa, NRb and chromaticity.• All systems gave the same results with very low

uncertainties.• All systems showed that NRa and NRb were

essentially constant across a wide luminance range for each display.

• All systems showed chromaticity was essentially constant with luminance for each display.



General ConclusionsGeneral Conclusions• Developments over the past year have made

it possible to design a new type of system for NVIS display measurements.

• This new type of system represents a quantum leap in performance and value.

• All the wish-list items are fulfilled.

the future of nvis display measurement ali advanced seminar, 2006optronic laboratories dr. richard...

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