Image perception and enhancement for the visually impaired

Myers, Lemuel R.; Rogers, Steven K.; Kabrisky, Matthew; Burns, Thomas J.

doi:10.1109/51.464776

Cited by 11 publications

(5 citation statements)

References 19 publications

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“…Of people with spectacle-mounted telescopes about 80-50% report using them for watching TV. 16,17 Image processing for vision rehabilitation, first proposed in the 1980s, 18,19 has been evaluated for contrast enhancement, 15,18,[20][21][22][23][24][25][26] image binarisation, 19,20,24,27 and edge enhancement. 3,14,28 In general, image enhancement has been shown to improve the perceived image quality, 3,14,23,25,26,29 was often selected (adjusted) over original images 14,15,25,30 and improved performance 20,25 for people with vision impairment.…”

Section: Introductionmentioning

confidence: 99%

Television, computer and portable display device use by people with central vision impairment

Woods

Satgunam

2011

Ophthalmic Physiologic Optic

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Purpose-To survey the viewing experience (e.g. hours watched, difficulty) and viewing metrics (e.g. distance viewed, display size) for television (TV), computers and portable visual display devices for normally-sighted (NS) and visually impaired participants. This information may guide visual rehabilitation.Methods-Survey was administered either in person or in a telephone interview on 223 participants of whom 104 had low vision (LV, worse than 6/18, age 22 to 90y, 54 males), and 94 were NS (visual acuity 6/9 or better, age 20 to 86y, 50 males). Depending on their situation, NS participants answered up to 38 questions and LV participants answered up to a further 10 questions.Results-Many LV participants reported at least "some" difficulty watching TV (71/103), reported at least "often" having difficulty with computer displays (40/76) and extreme difficulty watching videos on handheld devices (11/16). The average daily TV viewing was slightly, but not significantly, higher for the LV participants (3.6h) than the NS (3.0h). Only 18% of LV participants used visual aids (all optical) to watch TV. Most LV participants obtained effective magnification from a reduced viewing distance for both TV and computer display. Younger LV participants also used a larger display when compared to older LV participants to obtain increased magnification. About half of the TV viewing time occurred in the absence of a companion for both the LV and the NS participants. The mean number of TVs at home reported by LV participants (2.2) was slightly but not significantly (p=0.09) higher than NS participants (2.0). LV participants were equally likely to have a computer but were significantly (p=0.004) less likely to access the internet (73/104) compared to NS participants (82/94). Most LV participants expressed an interest in image enhancing technology for TV viewing (67/104) and for computer use (50/74), if they used a computer.Conclusion-In this study, both NS and LV participants had comparable video viewing habits. Most LV participants in our sample reported difficulty watching TV, and indicated an interest in assistive technology, such as image enhancement. As our participants reported that at least half their video viewing hours are spent alone and that there is usually more than one TV per household, this suggests that there are opportunities to use image enhancement on the TVs of LV viewers without interfering with the viewing experience of NS viewers.

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Section: Introductionmentioning

confidence: 99%

Television, computer and portable display device use by people with central vision impairment

Woods

Satgunam

2011

Ophthalmic Physiologic Optic

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“…[12,13] General contrast enhancement can increase the visibility of information in a video image (i.e., via histogram equalization [13,14]). A spatial filtering algorithm, the adaptive enhancement, first applied by Peli and colleagues [12,15] and later adopted by others [16,17] applies band pass (or band enhance) filtering to increase contrast at those spatial frequencies to which people with visual impairment have reduced sensitivity. Such band enhancement has been applied to static images [15][16][17][18][19], analog videos [20][21][22][23] and digital compressed videos.…”

Section: Introductionmentioning

confidence: 99%

“…A spatial filtering algorithm, the adaptive enhancement, first applied by Peli and colleagues [12,15] and later adopted by others [16,17] applies band pass (or band enhance) filtering to increase contrast at those spatial frequencies to which people with visual impairment have reduced sensitivity. Such band enhancement has been applied to static images [15][16][17][18][19], analog videos [20][21][22][23] and digital compressed videos. [24,25] Other approaches include converting the images to binary high contrast images using adaptive thresholding [13,15,17,26] and adding high contrast edges to the image.…”

Section: Introductionmentioning

confidence: 99%

Measuring perceived video quality of MPEG enhancement by people with impaired vision

et al. 2007

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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 (4 min 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.

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“…The basic approach proposed by Peli and adopted by others for enhancement of images (Isenberg et al. , 1989; Myers et al. , 1995; Omoruyi et al.…”

Section: Introductionmentioning

confidence: 99%

Recognition performance and perceived quality of video enhanced for the visually impaired

Peli

2005

Ophthalmic Physiologic Optic

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SummarySubjects with central field loss (CFL) individually selected enhancement parameters to improve visibility of static video images. The effect of enhancement on performance and on perceived quality of motion video was assessed. Performance, e.g., recognition of visual details, was assessed by having subjects answer questions regarding visual information contained in the video motion segments that were enhanced using the individually selected parameters. Enhancement did not improve subject performance on questions about video content. This result might be due to a ceiling effect limitation of the performance assessment method. In a second procedure, subjects' continuous perceptions of quality (using an adjective-based rating scale) were made while the enhancement parameters were abruptly switched among multiple values (including the individually selected enhancements, as well as unenhanced, over-enhanced, and degraded segments. The results indicate that adaptive enhancement (individually-tuned using a static image) adds significantly to perceived image quality when viewing motion video. Subjects who selected stronger contrast enhancement also perceived the enhancement to provide a larger benefit in image quality.

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Image perception and enhancement for the visually impaired

Cited by 11 publications

References 19 publications

Television, computer and portable display device use by people with central vision impairment

Television, computer and portable display device use by people with central vision impairment

Measuring perceived video quality of MPEG enhancement by people with impaired vision

Recognition performance and perceived quality of video enhanced for the visually impaired

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