Abstract

We used a new method to measure the perceived quality of contrast-enhanced motion video. Patients with impaired vision (n=24) and normally sighted subjects (n=6) adjusted the level of MPEG-based enhancement of 8 videos (4min each) drawn from 4 categories. They selected the level of enhancement that provided the preferred view of the videos, using a decreasing-step-size staircase procedure. Most patients made consistent selections of the preferred level of enhancement, indicating an appreciation of and a perceived benefit from the MPEG-based enhancement. The selections varied between patients and were correlated with letter contrast sensitivity, but the selections were not affected by training, experience, or video category. We measured just noticeable differences directly for videos and mapped the image manipulation (enhancement in our case) onto an approximately linear perceptual space. These tools and approaches will be of value in other evaluations of the image quality of motion video manipulations.

© 2007 Optical Society of America

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2006 (5)

C. Bunce and R. Wormald, "Leading causes of certification for blindness and partial sight in England & Wales," BMC Public Health 6, 1-7 (2006).
[CrossRef]

J. Mitchell and C. Bradley, "Quality of life in age-related macular degeneration: a review of the literature," Health Qual. Life Outcomes 4, 97 (2006).
[CrossRef] [PubMed]

J. B. Hassell, E. L. Lamoureux, and J. E. Keeffe, "Impact of age related macular degeneration on quality of life," Br. J. Ophthamol. 90, 593-596 (2006).
[CrossRef]

M. Fullerton and E. Peli, "Post-transmission digital video enhancement for people with visual impairments," J. Soc. Inf. Disp. 14, 15-24 (2006).
[CrossRef] [PubMed]

E. A. Krupinski, "Using the human observer to assess medical image display quality," J. Soc. Inf. Disp. 14, 927-932 (2006).
[CrossRef]

2005 (2)

S. J. Leat, G. Omoruyi, A. Kennedy, and E. Jernigan, "Generic and customized digital image enhancement filters for the visually impaired," Vision Res. 45, 1991-2007 (2005).
[CrossRef] [PubMed]

E. Peli, "Recognition performance and perceived quality of video enhanced for the visually impaired," Ophthalmic Physiol. Opt. 25, 543-555 (2005).
[CrossRef] [PubMed]

2004 (5)

J. Kim, A. Vora, and E. Peli, "MPEG-based image enhancement for the visually impaired," Opt. Eng. 43, 1318-1328 (2004).
[CrossRef]

J. Tang, J. Kim, and E. Peli, "Image enhancement in the JPEG domain for people with vision impairment," IEEE Trans. Biomed. Eng. 51, 2013-2023 (2004).
[CrossRef] [PubMed]

N. Congdon, B. O'Colmain, C. C. Klaver, R. Klein, B. Munoz, D. S. Friedman, J. Kempen, H. R. Taylor, and P. Mitchell, "Causes and prevalence of visual impairment among adults in the United States," Arch. Ophthalmol. (Chicago) 122, 477-485 (2004).
[CrossRef]

J. M. Seddon and C. A. Chen, "The epidemiology of age-related macular degeneration," Int. Ophthalmol. Clin. 44, 17-39 (2004).
[CrossRef] [PubMed]

E. Peli, J. Kim, Y. Yitzhaky, R. B. Goldstein, and R. L. Woods, "Wideband enhancement of television images for people with visual impairment," J. Opt. Soc. Am. A 21, 937-950 (2004).
[CrossRef]

2003 (2)

J. Tang, E. Peli, and S. Acton, "Image enhancement using a contrast measure in the compressed domain," IEEE Signal Process. Lett. 10, 289-292 (2003).
[CrossRef]

I. L. Bailey, S. N. Fitz, and G. A. Akinlabi, "Contrast sensitivity and efficiency at search and detection tasks (Abstract)," Invest. Ophthalmol. Visual Sci. 44, 2771 (2003).

2002 (1)

M. A. Webster, M. A. Georgeson, and S. M. Webster, "Neural adjustments to image blur," Nat. Neurosci. 5, 839-840 (2002).
[CrossRef]

2001 (4)

1999 (1)

E. Peli, "Simple 1-D enhancement for head-mounted low vision aid," Vis. Impair. Res. 1, 3-10 (1999).
[CrossRef]

1998 (2)

R. A. Applegate, H. C. Howland, R. P. Sharp, A. J. Cottingham, and R. W. Yee, "Corneal aberrations and visual performance after radial keratotomy," J. Refract. Surg. 14, 397-407 (1998).
[PubMed]

M. Garcia-Perez, "Forced-choice staircases with fixed step sizes: asymptotic and small-sample properties," Vision Res. 38, 1861-1881 (1998).
[CrossRef] [PubMed]

1996 (4)

1995 (2)

L. Myers, S. Rogers, M. Kabrisky, and T. Burns, "Image perception and enhancement for the visually impaired," IEEE Eng. Med. Biol. Mag. , Sept./Oct., 14(5), 594-602 (1995).
[CrossRef]

R. Hamberg and H. de Ridder, "Continuous assessment of perceptual image quality," J. Opt. Soc. Am. A 12, 2573-2577 (1995).
[CrossRef]

1994 (1)

1993 (2)

R. W. Massof, "High-tech help for low vision," NASA Tech Briefs 17, 20-22 (1993).

E. Peli, "Enhancement of retinal images: pros and problems," Neurosci. Biobehav. Rev. 17, 477-482 (1993).
[CrossRef]

1992 (1)

E. Peli, "Perception and interpretation of high-pass filtered images," Opt. Eng. 31, 74-81 (1992).
[CrossRef]

1991 (1)

E. Peli, R. B. Goldstein, G. M. Young, C. L. Trempe, and S. M. Buzney, "Image enhancement for the visually impaired: simulations and experimental results," Invest. Ophthalmol. Visual Sci. 32, 2337-2350 (1991).

1990 (1)

B. J. Cronin and S. R. King, "The development of the descriptive video service," J. Vis. Impair. Blind. 84, 503-506 (1990).

1989 (1)

L. Isenberg, A. Luebker, and G. E. Legge, "Image enhancement of faces for normal and low vision (abstract)," Invest. Ophthalmol. Visual Sci. 30, S396 (1989).

1986 (2)

E. Peli, L. E. Arend, Jr., and G. T. Timberlake, "Computerized image enhancement for low vision: New technology, new possibilities," J. Vis. Impair. Blind. 80, 849-854 (1986).

G. T. Timberlake, M. A. Mainster, E. Peli, R. A. Augliere, E. A. Essock, and L. E. Arend, "Reading with a macular scotoma I. Retinal location of scotoma and fixation area," Invest. Ophthalmol. Visual Sci. 27, 1137-1147 (1986).

1984 (1)

E. Peli and T. Peli, "Image enhancement for the visually impaired," Opt. Eng. 23, 47-51 (1984).

1982 (1)

F. L. Ferris, 3rd, A. Kassoff, G. H. Bresnick, and I. Bailey, "New visual acuity charts for clinical research," Am. J. Ophthalmol. 94, 91-96 (1982).

1981 (1)

J. E. Kitchin and I. Bailey, "Task complexity and visual acuity in senile macular degeneration," Aust. J. Optom. 64, 235-242 (1981).

Am. J. Ophthalmol. (1)

F. L. Ferris, 3rd, A. Kassoff, G. H. Bresnick, and I. Bailey, "New visual acuity charts for clinical research," Am. J. Ophthalmol. 94, 91-96 (1982).

Arch. Ophthalmol. (Chicago) (1)

N. Congdon, B. O'Colmain, C. C. Klaver, R. Klein, B. Munoz, D. S. Friedman, J. Kempen, H. R. Taylor, and P. Mitchell, "Causes and prevalence of visual impairment among adults in the United States," Arch. Ophthalmol. (Chicago) 122, 477-485 (2004).
[CrossRef]

Aust. J. Optom. (1)

J. E. Kitchin and I. Bailey, "Task complexity and visual acuity in senile macular degeneration," Aust. J. Optom. 64, 235-242 (1981).

BMC Public Health (1)

C. Bunce and R. Wormald, "Leading causes of certification for blindness and partial sight in England & Wales," BMC Public Health 6, 1-7 (2006).
[CrossRef]

Br. J. Ophthamol. (1)

J. B. Hassell, E. L. Lamoureux, and J. E. Keeffe, "Impact of age related macular degeneration on quality of life," Br. J. Ophthamol. 90, 593-596 (2006).
[CrossRef]

Health Qual. Life Outcomes (1)

J. Mitchell and C. Bradley, "Quality of life in age-related macular degeneration: a review of the literature," Health Qual. Life Outcomes 4, 97 (2006).
[CrossRef] [PubMed]

IEEE Eng. Med. Biol. Mag. (1)

L. Myers, S. Rogers, M. Kabrisky, and T. Burns, "Image perception and enhancement for the visually impaired," IEEE Eng. Med. Biol. Mag. , Sept./Oct., 14(5), 594-602 (1995).
[CrossRef]

IEEE Signal Process. Lett. (1)

J. Tang, E. Peli, and S. Acton, "Image enhancement using a contrast measure in the compressed domain," IEEE Signal Process. Lett. 10, 289-292 (2003).
[CrossRef]

IEEE Trans. Biomed. Eng. (1)

J. Tang, J. Kim, and E. Peli, "Image enhancement in the JPEG domain for people with vision impairment," IEEE Trans. Biomed. Eng. 51, 2013-2023 (2004).
[CrossRef] [PubMed]

Int. Ophthalmol. Clin. (1)

J. M. Seddon and C. A. Chen, "The epidemiology of age-related macular degeneration," Int. Ophthalmol. Clin. 44, 17-39 (2004).
[CrossRef] [PubMed]

Invest. Ophthalmol. Visual Sci. (4)

G. T. Timberlake, M. A. Mainster, E. Peli, R. A. Augliere, E. A. Essock, and L. E. Arend, "Reading with a macular scotoma I. Retinal location of scotoma and fixation area," Invest. Ophthalmol. Visual Sci. 27, 1137-1147 (1986).

L. Isenberg, A. Luebker, and G. E. Legge, "Image enhancement of faces for normal and low vision (abstract)," Invest. Ophthalmol. Visual Sci. 30, S396 (1989).

E. Peli, R. B. Goldstein, G. M. Young, C. L. Trempe, and S. M. Buzney, "Image enhancement for the visually impaired: simulations and experimental results," Invest. Ophthalmol. Visual Sci. 32, 2337-2350 (1991).

I. L. Bailey, S. N. Fitz, and G. A. Akinlabi, "Contrast sensitivity and efficiency at search and detection tasks (Abstract)," Invest. Ophthalmol. Visual Sci. 44, 2771 (2003).

J. Opt. Soc. Am. A (9)

J. Refract. Surg. (1)

R. A. Applegate, H. C. Howland, R. P. Sharp, A. J. Cottingham, and R. W. Yee, "Corneal aberrations and visual performance after radial keratotomy," J. Refract. Surg. 14, 397-407 (1998).
[PubMed]

J. Soc. Inf. Disp. (2)

M. Fullerton and E. Peli, "Post-transmission digital video enhancement for people with visual impairments," J. Soc. Inf. Disp. 14, 15-24 (2006).
[CrossRef] [PubMed]

E. A. Krupinski, "Using the human observer to assess medical image display quality," J. Soc. Inf. Disp. 14, 927-932 (2006).
[CrossRef]

J. Vis. Impair. Blind. (3)

B. J. Cronin and S. R. King, "The development of the descriptive video service," J. Vis. Impair. Blind. 84, 503-506 (1990).

E. Peli, E. M. Fine, and A. T. Labianca, "Evaluating visual information provided by audio description," J. Vis. Impair. Blind. 90, 378-385 (1996).

E. Peli, L. E. Arend, Jr., and G. T. Timberlake, "Computerized image enhancement for low vision: New technology, new possibilities," J. Vis. Impair. Blind. 80, 849-854 (1986).

NASA Tech Briefs (1)

R. W. Massof, "High-tech help for low vision," NASA Tech Briefs 17, 20-22 (1993).

Nat. Neurosci. (1)

M. A. Webster, M. A. Georgeson, and S. M. Webster, "Neural adjustments to image blur," Nat. Neurosci. 5, 839-840 (2002).
[CrossRef]

Neurosci. Biobehav. Rev. (1)

E. Peli, "Enhancement of retinal images: pros and problems," Neurosci. Biobehav. Rev. 17, 477-482 (1993).
[CrossRef]

Ophthalmic Physiol. Opt. (1)

E. Peli, "Recognition performance and perceived quality of video enhanced for the visually impaired," Ophthalmic Physiol. Opt. 25, 543-555 (2005).
[CrossRef] [PubMed]

Opt. Eng. (3)

J. Kim, A. Vora, and E. Peli, "MPEG-based image enhancement for the visually impaired," Opt. Eng. 43, 1318-1328 (2004).
[CrossRef]

E. Peli, "Perception and interpretation of high-pass filtered images," Opt. Eng. 31, 74-81 (1992).
[CrossRef]

E. Peli and T. Peli, "Image enhancement for the visually impaired," Opt. Eng. 23, 47-51 (1984).

Optom. Vision Sci. (1)

M. A. Garcia-Perez, "Yes-no staircases with fixed step sizes: psychometric properties and optimal setup," Optom. Vision Sci. 78, 56-64. (2001).
[CrossRef]

Vis. Impair. Res. (1)

E. Peli, "Simple 1-D enhancement for head-mounted low vision aid," Vis. Impair. Res. 1, 3-10 (1999).
[CrossRef]

Vision Res. (2)

M. Garcia-Perez, "Forced-choice staircases with fixed step sizes: asymptotic and small-sample properties," Vision Res. 38, 1861-1881 (1998).
[CrossRef] [PubMed]

S. J. Leat, G. Omoruyi, A. Kennedy, and E. Jernigan, "Generic and customized digital image enhancement filters for the visually impaired," Vision Res. 45, 1991-2007 (2005).
[CrossRef] [PubMed]

Other (15)

U. S. Census Bureau, "U.S. interim projections by age, sex, race, and Hispanic origin," (U.S. Census Bureau, Population Division, Population Projections Branch). Available at http://www.census.gov/ipc/www/usinterimproj/ (2004).

K. J. Ciuffreda, Amblyopia: Basic and Clinical Aspects (Butterworth-Heinemann, 1991), pp. 343-348.

J. Packer and C. Kirchner, "Who's watching? A profile of the blind and visually impaired audience for television and video" (American Foundation for the Blind). Available at http://www.afb.org/section.asp?SectionID=3&=140&=1232 (1997).

Z. Wang and A. C. Bovik, Modern Image Quality Assessment, Synthesis Lectures on Image, Video & Multimedia Processing (Morgan & Claypool, 2006), 146 pp.

G. M. Johnson and M. D. Fairchild, "Sharpness rules," in Proceedings of the 8th IS&T/SID Color Imaging Conference: Color Science and Engineering (Society for Imaging Science and Technology/Society for Information Display, 2000), pp. 24-30.

Due to a rounding error in the experimental code, only 97 of 213 (46%) of these first double-reversals with an intermediate step within the postexploratory phase correctly transitioned the staircase to the 1 JND (settled) stage (thus delaying the transition to another reversal where there was no intermediate step, or to one with an intermediate step where the error did not occur). There was no significant effect on the Enhancement Level selected by patients whose staircases experienced this error (Wilcoxon Signed Rank, z23=−0.17, p=0.86) nor was there any significant effect on chosen level when staircases naturally did not reach the 1 JND level, compared to those that transitioned correctly (Wilcoxon Signed Rank, z9⩽−0.15, p⩾0.44).

M. Fullerton and E. Peli, "People with visual impairment prefer TV viewing using a contrast enhancement consumer product," in SID International Symposium Digest of Technical Papers (Society for Information Display, 2007), Vol. 38, paper 15.4, pp. 975-978.
[CrossRef]

E. Peli, E. M. Fine, and K. Pisano, "Video enhancement of text and movies for the visually impaired," in Low Vision: Research and New Developments in Rehabilitation, A.C.Kooijman, P.L.Looijestijn, J.A.Welling, and G.J.van der Wildt, eds. (IOS Press, 1994), pp. 191-198.

E. M. Fine, E. Peli, and N. Brady, "Evaluating video enhancement for visually impaired viewers," in Proceedings of Vision '96: V International Conference on Low Vision (ONCE, 1996), Vol. 1, pp. 85-92.

J. Lubin, "A visual discrimination model for imaging system design and evaluation," in Vision Models for Target Detection, E.Peli, ed. (World Scientific, 1995), pp. 245-283.

A. B. Watson, "The spatial standard observer: a human vision model for display inspection," in SID Symposium Digest of Technical Papers (Society for Information Display, 2006), Vol. 31, paper 31.1, pp. 1312-1315.
[CrossRef]

E. Peli, "Image enhancement for impaired vision: the challenge of evaluation," in Proceedings of the 1st International IEEE Symposium on Research on Assistive Technologies (IEEE Computer Society, 2007), pp. 47-58.

J. Xia, S. L. Qin, L. Liu, I. Heynderickx, and H. C. Yin, "The just noticeable difference in chromaticity, black level, white level and contour rendering in natural images," in Proceedings of the 12th International Display Workshops in conjunction with Asia Display 2005 (Society for Information Display, 2005), pp. 1821-1824.

E. Peli, T. R. Hedges, J. Tang, and D. Landmann, "A binocular stereoscopic display system with coupled convergence and accommodation demands," in SID International Symposium Digest of Technical Papers (Society for Information Display, 2001), Vol. 32, paper 53.2, pp. 1296-1299.
[CrossRef]

E. A. Krupinski, H. Roehrig, and J. Fan, "Influence of 8-bit vs. 11-bit digital medical displays on observer performance and visual search," in SID International Symposium Digest of Technical Papers (Society for Information Display, 2007), Vol. 38, paper 15.1, pp. 965-966.
[CrossRef]

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Figures (8)

Fig. 1
Fig. 1

Examples of the effect of MPEG image enhancement on two video frames. The top row is the original ( k = 0 ) , the middle row is the level of enhancement chosen by patient 12 in the main experiment ( k = 5 ) , and the bottom row is the level of enhancement chosen by patient 24 in the main experiment ( k = 13.6 ) . In the main experiment, all 24 patients with visual impairment chose an image enhancement with k > 0 (Fig. 7). Left-hand frames, © Discovery Communications, LLC, courtesy of Discovery FootageSource; right-hand frames, © Champ Car World Series, LLC. Both images are used with the permission of the copyright holder.

Fig. 2
Fig. 2

Illustration of the side-by-side video display used in the first and second preliminary experiments to characterize the MPEG-enhancement perceptual space. In the example, the left side is the original video ( k = 0 ) , the middle is a moderate level of enhancement ( k = 26 ) , and the right is the highest level of enhancement ( k = 80 ) used in these experiments. In the first preliminary experiment the observer adjusted the middle video to a level of enhancement perceptually halfway between the levels on either side. That process was repeated to further subdivide the perceptual space. In the second preliminary experiment the middle image video was the original ( k = 0 ) and on one side was a degraded video ( k = 9 ) . The observer adjusted the level of the enhancement of the other side to be perceptually as far from the original image as the degraded video.

Fig. 3
Fig. 3

For MPEG-enhanced videos ( k > 0 , above horizontal dashed line) there was an expansive relationship between perceived enhancement and k, and an approximately linear relationship for degraded videos ( k < 0 ) . Data for the two normally sighted observers are shown for the first (open symbols) and second (solid symbols) preliminary experiments. The extreme values of the negative and positive ranges used in the first preliminary experiment are shown as crosses. The fits, shown as a solid curve, were to the average of the two observers’ data in the first preliminary experiment. The comparison degraded video ( k = 9 ) used in the second preliminary experiment is shown as a solid circle. It was perceived to be as far below the dashed line (original video) as the enhanced videos were above that line, shown as solid triangle and square.

Fig. 4
Fig. 4

Illustration of the side-by-side video segments used to determine the JNDs in levels of MPEG enhancement in the third preliminary experiment. In this example the reference video is on the left, with k = 11.8 . The level of enhancement of the stimulus video on the right alternated every 850 ms between that of the reference video and a test level. The test level of enhancement was increased or decreased at every flicker cycle until the observer correctly reported the side that was flickering. The difference between the reference and test k at that time was the JND. The image shown on the right ( k = 35.4 ) represents 4 JNDs, as a single JND is hard to appreciate in print.

Fig. 5
Fig. 5

Measured JNDs of enhanced ( k > 0 , right of dashed vertical line) and degraded ( k < 0 ) videos as a function of the reference level of enhancement (Fig. 4). The JND increased linearly with the level of enhancement. Data for the two normally sighted observers, for increasing (“up”) and decreasing (“down”) levels of enhancement relative to the reference level are shown. The linear fits were to the average of all data at each reference level, separately for reference level above and below k = 0 .

Fig. 6
Fig. 6

Responses of 3 of the 30 patients (6 of which were excluded) to their first (left) and last (8th) (right) video. Each panel represents the staircase obtained for one video, composed of two 2 - min video segments. In each video segment the dashed vertical line represents the time of the second reversal and thus the commencement of the postexploratory phase. The solid vertical line in the middle of each panel represents the transition between the two video segments, at which time the level of enhancement was reset to an extreme value. The dotted horizontal line through the staircase represents the median of the staircase values in the post-exploratory phase. The bottom row shows the responses of one of the six patients who were excluded. This patient could not appreciate the MPEG enhancement and therefore alternated between the two extreme values (visual acuity 20 576 ). The first and second rows show responses of the median patient (#12, visual acuity 20 84 ) and the patient with the highest average chosen Enhancement Level (#24, visual acuity 20 152 ). Despite the occasional explorations, as was requested of the patients, these two patients clearly had a reliable preference for a certain level of enhancement.

Fig. 7
Fig. 7

Chosen Enhancement Level averaged across all 16 video segments for each of the 24 patients with visual impairment (solid squares) and 6 normally sighted subjects (open squares). The maximum and minimum chosen Enhancement Levels chosen for a video segment by each participant are shown as open triangles. Error bars are 95% confidence limits of the mean. All participants had average chosen Enhancements Levels significantly above zero (no enhancement), with only two patients choosing an Enhancement Level, each for only one video segment, that was not above zero. No patient had a chosen Enhancement Level above 0.55 ( k = 33 ) .

Fig. 8
Fig. 8

Planned analyses showed significant differences in the Enhancement Levels chosen by the 24 patients between some videos (where * denotes p < 0.05 ) . The Set 1 (open/white) video segments were all viewed before the Set 2 (gray) video segments. As the distributions of chosen Enhancement Levels across patients were not normally distributed, the median is shown, and error bars are first and third quartiles

Tables (1)

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Table 1 Descriptions of the Video Categories and the Videos Chosen To Illustrate Those Categories.

Equations (6)

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q i j = ( set i j × k ) + 1 .
set i j = s ( i + j ) , i , j = 0 : 7 ,
s ( 1 ) = 0.03 , s ( 2 ) = 0.08 ,
s ( n = 3 : 8 ) = 0.05 n ,
s ( n = 9 : 14 ) = 0.1 n 0.4 .
Enhancement Level = { ( k 75.5 ) 0.71 , k 0 k 21.05 , k < 0 } .

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