Abstract

An experimental method for measuring the veiling glare characteristics of display devices is presented. The measured veiling glare ratio (G) is taken to be the luminance in the surrounding bright field divided by the luminance in a dark circle. The method is based on a collimated conic probe that minimizes signal contamination from bright surroundings allowing for measurements of low luminance in a circular dark spot of a test pattern. A correction factor computed with test patterns having opaque spots is introduced. The factor is expressed as a bivariate function of the dark-spot radius and the distance between the probe and the emissive surface. We studied the uncertainty introduced by the method by measuring veiling glare test patterns printed on radiographic film for which the transmission of the dark spots was determined experimentally. Performance characterization measurements show that signal contamination is less than 10-4 of the bright field surrounding a dark circle. Our results show that G of a few hundred can be measured with an uncertainty of a few percent, and ratios of approximately 103 can be reported within 10%. Finally, we demonstrate the method by measuring G for a high-performance monochrome cathode-ray tube display.

© 2000 Optical Society of America

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References

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  1. E. B. Gindele, B. R. Gandhi, S. L. Shaffer, “A non-linear CRT system simulation model,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1990), pp. 785–788.
  2. A. Badano, M. J. Flynn, “Image degradation by glare in radiologic display devices,” in Medical Imaging 1997: Image Display, Y. Kim, ed., Proc. SPIE3031, 222–231 (1997).
    [CrossRef]
  3. J. R. Mansell, A. W. Woodhead, “Contrast loss in image devices due to electron backscattered from the fluorescent screen,” J. Phys. D 16, 2269–2278 (1983).
    [CrossRef]
  4. G. C. de Vries, “Contrast-enhancement under low ambient illumination,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1995), pp. 32–35.
  5. J. J. van Oekel, “Improving the contrast of CRTs under low ambient illumination with a graphite coating,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1995), pp. 427–430.
  6. J. J. van Oekel, M. J. Severens, G. M. H. Timmermans, “Improving contrast and color saturation of CRTs by Al2O3 shadow mask coating,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1997), pp. 436–439.
  7. A. Badano, M. J. Flynn, “Monte Carlo modeling of the luminance spread function in flat panel displays,” in Proceedings of the International Display Research Conference (Society for Information Display, Santa Ana, Calif., 1997), pp. 382–385.
  8. J. A. Seibert, O. Nalcioglu, W. Roeck, “Characterization of the veiling glare PSF in X-ray image intensified fluoroscopy,” Med. Phys. 11(2), 172–179 (1984).
    [CrossRef] [PubMed]
  9. H. D. Zeman, E. B. Hughes, J. N. Otis, “Veiling glare of a linear multichannel Si(Li) detector,” in Application of Optical Instrumentation in Medicine XIII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE535, 214–221 (1985).
    [CrossRef]
  10. E. Caruthers, “Monte Carlo studies of image spread by X-ray image intensifiers,” in Application of Optical Instrumentation in Medicine XIII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE535, 140–147 (1985).
    [CrossRef]
  11. N. Bromberg, J. Bickford, “Veiling glare in the imaging chain,” in Application of Optical Instrumentation in Medicine XII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE454, 387–391 (1984).
    [CrossRef]
  12. S. Matsuda, T. Nitoh, “Flare as applied to photographic lenses,” Appl. Opt. 11, 1850–1856 (1972).
    [CrossRef] [PubMed]
  13. C. Beckman, O. Nilsson, L.-E. Paulsson, “Intraocular light scattering in vision, artistic painting, and photography,” Appl. Opt. 33, 4749–4753 (1994).
    [CrossRef] [PubMed]
  14. G. Spencer, P. Shirley, K. Zimmerman, “Physically-based glare effects for digital images,” in Proceedings of the 22nd Annual ACM Conference on Computer Graphics (Association for Computing Machinery, New York, 1995), pp. 325–334.
  15. H. Blume, “Very-high-resolution CRT display systems,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1992), pp. 699–702.
  16. K. Rossmann, “Point-spread function, line-spread function, and modulation transfer function: tools for the study of imaging systems,” Radiology 93, 257–272 (1969).
    [PubMed]
  17. D. A. Baylor, M. G. F. Fuortes, “Electrical responses of single cones in the retina of the turtle,” J. Physiol. (London) 207, 77–92 (1970).
  18. R. A. Norman, F. S. Werblin, “Control of retinal sensitivity: light and dark adaptation of vertebrate rods and cones,” J. Gen. Physiol. 63, 37–61 (1974).
    [CrossRef]
  19. R. A. Norman, I. Perlman, “The effects of background illumination on the photoresponses of red and green cones,” J. Gen. Physiol. 286, 491–507 (1979).
  20. W. S. Stiles, B. H. Crawford, “The luminous efficiency of rays entering the eye pupil at different points,” Proc. R. Soc. London 122, 428–450 (1937).
  21. M. J. Flynn, T. McDonald, E. DiBello, “Flat panel display technology for high performance radiographic imaging,” in Medical Imaging 1995: Image Display, Y. Kim, ed., Proc. SPIE2431, 360–371 (1995).
    [CrossRef]
  22. P. A. Boynton, E. F. Kelley, “Measuring the contrast ratio of displays,” Inf. Disp. 11, 24–27 (1996).
  23. P. A. Boynton, E. F. Kelley, “Accurate contrast-ratio measurements using a cone mask,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1997), pp. 823–826.
  24. M. J. Flynn, J. Kanicki, A. Badano, W. R. Eyler, “High fidelity electronic display of digital radiographs,” Radiographics 19, 1653–1669 (1999).
    [CrossRef] [PubMed]

1999 (1)

M. J. Flynn, J. Kanicki, A. Badano, W. R. Eyler, “High fidelity electronic display of digital radiographs,” Radiographics 19, 1653–1669 (1999).
[CrossRef] [PubMed]

1996 (1)

P. A. Boynton, E. F. Kelley, “Measuring the contrast ratio of displays,” Inf. Disp. 11, 24–27 (1996).

1994 (1)

1984 (1)

J. A. Seibert, O. Nalcioglu, W. Roeck, “Characterization of the veiling glare PSF in X-ray image intensified fluoroscopy,” Med. Phys. 11(2), 172–179 (1984).
[CrossRef] [PubMed]

1983 (1)

J. R. Mansell, A. W. Woodhead, “Contrast loss in image devices due to electron backscattered from the fluorescent screen,” J. Phys. D 16, 2269–2278 (1983).
[CrossRef]

1979 (1)

R. A. Norman, I. Perlman, “The effects of background illumination on the photoresponses of red and green cones,” J. Gen. Physiol. 286, 491–507 (1979).

1974 (1)

R. A. Norman, F. S. Werblin, “Control of retinal sensitivity: light and dark adaptation of vertebrate rods and cones,” J. Gen. Physiol. 63, 37–61 (1974).
[CrossRef]

1972 (1)

1970 (1)

D. A. Baylor, M. G. F. Fuortes, “Electrical responses of single cones in the retina of the turtle,” J. Physiol. (London) 207, 77–92 (1970).

1969 (1)

K. Rossmann, “Point-spread function, line-spread function, and modulation transfer function: tools for the study of imaging systems,” Radiology 93, 257–272 (1969).
[PubMed]

1937 (1)

W. S. Stiles, B. H. Crawford, “The luminous efficiency of rays entering the eye pupil at different points,” Proc. R. Soc. London 122, 428–450 (1937).

Badano, A.

M. J. Flynn, J. Kanicki, A. Badano, W. R. Eyler, “High fidelity electronic display of digital radiographs,” Radiographics 19, 1653–1669 (1999).
[CrossRef] [PubMed]

A. Badano, M. J. Flynn, “Monte Carlo modeling of the luminance spread function in flat panel displays,” in Proceedings of the International Display Research Conference (Society for Information Display, Santa Ana, Calif., 1997), pp. 382–385.

A. Badano, M. J. Flynn, “Image degradation by glare in radiologic display devices,” in Medical Imaging 1997: Image Display, Y. Kim, ed., Proc. SPIE3031, 222–231 (1997).
[CrossRef]

Baylor, D. A.

D. A. Baylor, M. G. F. Fuortes, “Electrical responses of single cones in the retina of the turtle,” J. Physiol. (London) 207, 77–92 (1970).

Beckman, C.

Bickford, J.

N. Bromberg, J. Bickford, “Veiling glare in the imaging chain,” in Application of Optical Instrumentation in Medicine XII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE454, 387–391 (1984).
[CrossRef]

Blume, H.

H. Blume, “Very-high-resolution CRT display systems,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1992), pp. 699–702.

Boynton, P. A.

P. A. Boynton, E. F. Kelley, “Measuring the contrast ratio of displays,” Inf. Disp. 11, 24–27 (1996).

P. A. Boynton, E. F. Kelley, “Accurate contrast-ratio measurements using a cone mask,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1997), pp. 823–826.

Bromberg, N.

N. Bromberg, J. Bickford, “Veiling glare in the imaging chain,” in Application of Optical Instrumentation in Medicine XII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE454, 387–391 (1984).
[CrossRef]

Caruthers, E.

E. Caruthers, “Monte Carlo studies of image spread by X-ray image intensifiers,” in Application of Optical Instrumentation in Medicine XIII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE535, 140–147 (1985).
[CrossRef]

Crawford, B. H.

W. S. Stiles, B. H. Crawford, “The luminous efficiency of rays entering the eye pupil at different points,” Proc. R. Soc. London 122, 428–450 (1937).

de Vries, G. C.

G. C. de Vries, “Contrast-enhancement under low ambient illumination,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1995), pp. 32–35.

DiBello, E.

M. J. Flynn, T. McDonald, E. DiBello, “Flat panel display technology for high performance radiographic imaging,” in Medical Imaging 1995: Image Display, Y. Kim, ed., Proc. SPIE2431, 360–371 (1995).
[CrossRef]

Eyler, W. R.

M. J. Flynn, J. Kanicki, A. Badano, W. R. Eyler, “High fidelity electronic display of digital radiographs,” Radiographics 19, 1653–1669 (1999).
[CrossRef] [PubMed]

Flynn, M. J.

M. J. Flynn, J. Kanicki, A. Badano, W. R. Eyler, “High fidelity electronic display of digital radiographs,” Radiographics 19, 1653–1669 (1999).
[CrossRef] [PubMed]

A. Badano, M. J. Flynn, “Monte Carlo modeling of the luminance spread function in flat panel displays,” in Proceedings of the International Display Research Conference (Society for Information Display, Santa Ana, Calif., 1997), pp. 382–385.

M. J. Flynn, T. McDonald, E. DiBello, “Flat panel display technology for high performance radiographic imaging,” in Medical Imaging 1995: Image Display, Y. Kim, ed., Proc. SPIE2431, 360–371 (1995).
[CrossRef]

A. Badano, M. J. Flynn, “Image degradation by glare in radiologic display devices,” in Medical Imaging 1997: Image Display, Y. Kim, ed., Proc. SPIE3031, 222–231 (1997).
[CrossRef]

Fuortes, M. G. F.

D. A. Baylor, M. G. F. Fuortes, “Electrical responses of single cones in the retina of the turtle,” J. Physiol. (London) 207, 77–92 (1970).

Gandhi, B. R.

E. B. Gindele, B. R. Gandhi, S. L. Shaffer, “A non-linear CRT system simulation model,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1990), pp. 785–788.

Gindele, E. B.

E. B. Gindele, B. R. Gandhi, S. L. Shaffer, “A non-linear CRT system simulation model,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1990), pp. 785–788.

Hughes, E. B.

H. D. Zeman, E. B. Hughes, J. N. Otis, “Veiling glare of a linear multichannel Si(Li) detector,” in Application of Optical Instrumentation in Medicine XIII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE535, 214–221 (1985).
[CrossRef]

Kanicki, J.

M. J. Flynn, J. Kanicki, A. Badano, W. R. Eyler, “High fidelity electronic display of digital radiographs,” Radiographics 19, 1653–1669 (1999).
[CrossRef] [PubMed]

Kelley, E. F.

P. A. Boynton, E. F. Kelley, “Measuring the contrast ratio of displays,” Inf. Disp. 11, 24–27 (1996).

P. A. Boynton, E. F. Kelley, “Accurate contrast-ratio measurements using a cone mask,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1997), pp. 823–826.

Mansell, J. R.

J. R. Mansell, A. W. Woodhead, “Contrast loss in image devices due to electron backscattered from the fluorescent screen,” J. Phys. D 16, 2269–2278 (1983).
[CrossRef]

Matsuda, S.

McDonald, T.

M. J. Flynn, T. McDonald, E. DiBello, “Flat panel display technology for high performance radiographic imaging,” in Medical Imaging 1995: Image Display, Y. Kim, ed., Proc. SPIE2431, 360–371 (1995).
[CrossRef]

Nalcioglu, O.

J. A. Seibert, O. Nalcioglu, W. Roeck, “Characterization of the veiling glare PSF in X-ray image intensified fluoroscopy,” Med. Phys. 11(2), 172–179 (1984).
[CrossRef] [PubMed]

Nilsson, O.

Nitoh, T.

Norman, R. A.

R. A. Norman, I. Perlman, “The effects of background illumination on the photoresponses of red and green cones,” J. Gen. Physiol. 286, 491–507 (1979).

R. A. Norman, F. S. Werblin, “Control of retinal sensitivity: light and dark adaptation of vertebrate rods and cones,” J. Gen. Physiol. 63, 37–61 (1974).
[CrossRef]

Otis, J. N.

H. D. Zeman, E. B. Hughes, J. N. Otis, “Veiling glare of a linear multichannel Si(Li) detector,” in Application of Optical Instrumentation in Medicine XIII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE535, 214–221 (1985).
[CrossRef]

Paulsson, L.-E.

Perlman, I.

R. A. Norman, I. Perlman, “The effects of background illumination on the photoresponses of red and green cones,” J. Gen. Physiol. 286, 491–507 (1979).

Roeck, W.

J. A. Seibert, O. Nalcioglu, W. Roeck, “Characterization of the veiling glare PSF in X-ray image intensified fluoroscopy,” Med. Phys. 11(2), 172–179 (1984).
[CrossRef] [PubMed]

Rossmann, K.

K. Rossmann, “Point-spread function, line-spread function, and modulation transfer function: tools for the study of imaging systems,” Radiology 93, 257–272 (1969).
[PubMed]

Seibert, J. A.

J. A. Seibert, O. Nalcioglu, W. Roeck, “Characterization of the veiling glare PSF in X-ray image intensified fluoroscopy,” Med. Phys. 11(2), 172–179 (1984).
[CrossRef] [PubMed]

Severens, M. J.

J. J. van Oekel, M. J. Severens, G. M. H. Timmermans, “Improving contrast and color saturation of CRTs by Al2O3 shadow mask coating,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1997), pp. 436–439.

Shaffer, S. L.

E. B. Gindele, B. R. Gandhi, S. L. Shaffer, “A non-linear CRT system simulation model,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1990), pp. 785–788.

Shirley, P.

G. Spencer, P. Shirley, K. Zimmerman, “Physically-based glare effects for digital images,” in Proceedings of the 22nd Annual ACM Conference on Computer Graphics (Association for Computing Machinery, New York, 1995), pp. 325–334.

Spencer, G.

G. Spencer, P. Shirley, K. Zimmerman, “Physically-based glare effects for digital images,” in Proceedings of the 22nd Annual ACM Conference on Computer Graphics (Association for Computing Machinery, New York, 1995), pp. 325–334.

Stiles, W. S.

W. S. Stiles, B. H. Crawford, “The luminous efficiency of rays entering the eye pupil at different points,” Proc. R. Soc. London 122, 428–450 (1937).

Timmermans, G. M. H.

J. J. van Oekel, M. J. Severens, G. M. H. Timmermans, “Improving contrast and color saturation of CRTs by Al2O3 shadow mask coating,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1997), pp. 436–439.

van Oekel, J. J.

J. J. van Oekel, M. J. Severens, G. M. H. Timmermans, “Improving contrast and color saturation of CRTs by Al2O3 shadow mask coating,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1997), pp. 436–439.

J. J. van Oekel, “Improving the contrast of CRTs under low ambient illumination with a graphite coating,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1995), pp. 427–430.

Werblin, F. S.

R. A. Norman, F. S. Werblin, “Control of retinal sensitivity: light and dark adaptation of vertebrate rods and cones,” J. Gen. Physiol. 63, 37–61 (1974).
[CrossRef]

Woodhead, A. W.

J. R. Mansell, A. W. Woodhead, “Contrast loss in image devices due to electron backscattered from the fluorescent screen,” J. Phys. D 16, 2269–2278 (1983).
[CrossRef]

Zeman, H. D.

H. D. Zeman, E. B. Hughes, J. N. Otis, “Veiling glare of a linear multichannel Si(Li) detector,” in Application of Optical Instrumentation in Medicine XIII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE535, 214–221 (1985).
[CrossRef]

Zimmerman, K.

G. Spencer, P. Shirley, K. Zimmerman, “Physically-based glare effects for digital images,” in Proceedings of the 22nd Annual ACM Conference on Computer Graphics (Association for Computing Machinery, New York, 1995), pp. 325–334.

Appl. Opt. (2)

Inf. Disp. (1)

P. A. Boynton, E. F. Kelley, “Measuring the contrast ratio of displays,” Inf. Disp. 11, 24–27 (1996).

J. Gen. Physiol. (2)

R. A. Norman, F. S. Werblin, “Control of retinal sensitivity: light and dark adaptation of vertebrate rods and cones,” J. Gen. Physiol. 63, 37–61 (1974).
[CrossRef]

R. A. Norman, I. Perlman, “The effects of background illumination on the photoresponses of red and green cones,” J. Gen. Physiol. 286, 491–507 (1979).

J. Phys. D (1)

J. R. Mansell, A. W. Woodhead, “Contrast loss in image devices due to electron backscattered from the fluorescent screen,” J. Phys. D 16, 2269–2278 (1983).
[CrossRef]

J. Physiol. (London) (1)

D. A. Baylor, M. G. F. Fuortes, “Electrical responses of single cones in the retina of the turtle,” J. Physiol. (London) 207, 77–92 (1970).

Med. Phys. (1)

J. A. Seibert, O. Nalcioglu, W. Roeck, “Characterization of the veiling glare PSF in X-ray image intensified fluoroscopy,” Med. Phys. 11(2), 172–179 (1984).
[CrossRef] [PubMed]

Proc. R. Soc. London (1)

W. S. Stiles, B. H. Crawford, “The luminous efficiency of rays entering the eye pupil at different points,” Proc. R. Soc. London 122, 428–450 (1937).

Radiographics (1)

M. J. Flynn, J. Kanicki, A. Badano, W. R. Eyler, “High fidelity electronic display of digital radiographs,” Radiographics 19, 1653–1669 (1999).
[CrossRef] [PubMed]

Radiology (1)

K. Rossmann, “Point-spread function, line-spread function, and modulation transfer function: tools for the study of imaging systems,” Radiology 93, 257–272 (1969).
[PubMed]

Other (13)

E. B. Gindele, B. R. Gandhi, S. L. Shaffer, “A non-linear CRT system simulation model,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1990), pp. 785–788.

A. Badano, M. J. Flynn, “Image degradation by glare in radiologic display devices,” in Medical Imaging 1997: Image Display, Y. Kim, ed., Proc. SPIE3031, 222–231 (1997).
[CrossRef]

M. J. Flynn, T. McDonald, E. DiBello, “Flat panel display technology for high performance radiographic imaging,” in Medical Imaging 1995: Image Display, Y. Kim, ed., Proc. SPIE2431, 360–371 (1995).
[CrossRef]

H. D. Zeman, E. B. Hughes, J. N. Otis, “Veiling glare of a linear multichannel Si(Li) detector,” in Application of Optical Instrumentation in Medicine XIII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE535, 214–221 (1985).
[CrossRef]

E. Caruthers, “Monte Carlo studies of image spread by X-ray image intensifiers,” in Application of Optical Instrumentation in Medicine XIII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE535, 140–147 (1985).
[CrossRef]

N. Bromberg, J. Bickford, “Veiling glare in the imaging chain,” in Application of Optical Instrumentation in Medicine XII, S. J. Dwyer, R. H. Schneider, eds., Proc. SPIE454, 387–391 (1984).
[CrossRef]

G. Spencer, P. Shirley, K. Zimmerman, “Physically-based glare effects for digital images,” in Proceedings of the 22nd Annual ACM Conference on Computer Graphics (Association for Computing Machinery, New York, 1995), pp. 325–334.

H. Blume, “Very-high-resolution CRT display systems,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1992), pp. 699–702.

G. C. de Vries, “Contrast-enhancement under low ambient illumination,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1995), pp. 32–35.

J. J. van Oekel, “Improving the contrast of CRTs under low ambient illumination with a graphite coating,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1995), pp. 427–430.

J. J. van Oekel, M. J. Severens, G. M. H. Timmermans, “Improving contrast and color saturation of CRTs by Al2O3 shadow mask coating,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1997), pp. 436–439.

A. Badano, M. J. Flynn, “Monte Carlo modeling of the luminance spread function in flat panel displays,” in Proceedings of the International Display Research Conference (Society for Information Display, Santa Ana, Calif., 1997), pp. 382–385.

P. A. Boynton, E. F. Kelley, “Accurate contrast-ratio measurements using a cone mask,” in Digest of Technical Papers (Society of Information Display, Santa Ana, Calif., 1997), pp. 823–826.

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Figures (9)

Fig. 1
Fig. 1

Computer graphic patterns for veiling glare. During the measurements, the bright circular-field diameter is maintained constant at 20 cm, whereas the dark-spot diameter is varyed from 0 up to the bright-field diameter.

Fig. 2
Fig. 2

Photopic probe for measurements of veiling glare ratio.

Fig. 3
Fig. 3

Schematic drawing of the collimated probe showing the dimensions in centimeters and the relative position of apertures and baffles.

Fig. 4
Fig. 4

Design drawings for the photopic probe showing aspects of the optical design. (a) Principal rays that define the detector direct field of view. (b) Baffle positioning and back surfaces viewed by the detector. (c) Scattered rays absorbed by multiple reflections in the conic probe.

Fig. 5
Fig. 5

Experimentally measured probe response values as a function of the opaque spot radius for distances of 2, 10, and 20 mm between the tip of the probe and the emissive surface. The factor is expressed as a fraction of the bright region signal. The bright circular region was 320 mm in all cases.

Fig. 6
Fig. 6

Experimental data points plotted along with the correction function ζ curves for distances d of 2, 10, and 20 mm. The range of values represents the area where the function ζ(r d , d) is defined, namely, 3 × 10-5 < r d < 1 × 10-3 and 3 mm < d < 10 mm. The error bars represent a standard deviation of 20 consecutive measurements recorded at each point with the photometer.

Fig. 7
Fig. 7

Inverse veiling glare ratios measured for test patterns on radiographic film at distances of 5 and 15 mm. We computed the values for 1/G by subtracting the veiling glare ratio that is due to the known film transmission (T d ) and the correction factor ζ [see Eq. (9)] for each dark-spot diameter. Because of the veiling glare characteristics of radiographic film, the small values of 1/G for radii greater than 10 mm relate to the error introduced by the method.

Fig. 8
Fig. 8

Veiling glare ratio for a medical imaging CRT measured at a distance of 1 mm from the face-plate surface.

Fig. 9
Fig. 9

Ring response function for the medical imaging CRT. The magnitude of the tails caused by light transport processes that occur in the display emissive structures can be measured with this approach.

Tables (1)

Tables Icon

Table 1 Experimental Veiling Glare Ratiosa

Equations (10)

Equations on this page are rendered with MathJax. Learn more.

Lgx, y+Ix, y= Ix, y×Px-x, y-ydxdy,
Rr=02π Pr, θrdθ=2πrPr,
Lg=Lg0, 0=Iordrl Rrdr,
1Gi-1Gi+1=riri+1 Rrdr.
Lmeas=Lg+ζLb.
Gcorrrd, d=Gmeasrd, d11-ζrd, dGmeasrd, d.
log ζrd, d=0.00339d2-0.0778d-0.435rd-0.00120rdd2+0.0371rdd-1.85,
Lmeasrd=Lgrd+Tdrd+ζrd, dLb,
1Gcorrrd=1Gmeasrd-Tdrd-ζrd, d,
1Gcorrrd=1Gmeasrd-LdrdLb-ζrd, d,

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