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The Future of NVIS Display Measurement

The Future of NVIS Display Measurement. Dr. Richard Young Optronic Laboratories, Inc. Introduction. Thanks to the excellent quality of modern scanning instruments, NVIS compatibility measurements have become almost routine. What improvements could instrument manufacturers make…. Introduction.

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The Future of NVIS Display Measurement

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  1. The Future of NVIS Display Measurement Dr. Richard Young Optronic Laboratories, Inc.

  2. Introduction Thanks to the excellent quality of modern scanning instruments, NVIS compatibility measurements have become almost routine. What improvements could instrument manufacturers make…

  3. Introduction A wish-list for improvements… • 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

  4. Sensitivity and Variability Scanning systems have plenty of sensitivity Much of the variability is due to the longer wavelengths

  5. Sensitivity and Variability The OL 770-NVS detector is based on silicon, and hence has a different shape, There is no dramatic change in longer wavelength sensitivity

  6. Spectroradiometer design

  7. Spectroradiometer design

  8. Spectroradiometer design

  9. The 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

  10. Spectroradiometer 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

  11. MIL 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%

  12. MIL 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

  13. MIL 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

  14. Other 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

  15. Other 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

  16. An Intercomparison Study

  17. An Intercomparison Study Green B NVIS Yellow NVIS Red

  18. An Intercomparison Study

  19. An Intercomparison Study

  20. An Intercomparison Study

  21. An Intercomparison Study

  22. NVIS Green B Results For <1 second scan For 1-2 minute scan

  23. NVIS Green B Results For 2 minute scan For <1 second scan For 1-2 minute scan

  24. NVIS Green B Results

  25. NVIS Red Results

  26. NVIS Red Results

  27. NVIS Yellow Results

  28. NVIS Yellow Results

  29. Study 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.

  30. General 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.

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