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Characterizing crosstalk in anaglyphic stereoscopic images on LCD monitors and plasma displays

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In 1853, William Rollman 1 developed the inexpensive and easy to use anaglyph method for displaying stereoscopic images. Although it can be used with nearly any type of full-color display, the anaglyph method compromises the accuracy of color reproduction, and it often suffers from cros-stalk (or ghosting) between the left-and right-eye image channels. Crosstalk degrades the ability of the observer to fuse the stereoscopic image, and hence reduces the quality of the 3-D image. Crosstalk is present in various levels with most stereoscopic displays; however, it is often particularly evident with anaglyphic 3-D images. This paper summarizes the results of two projects that characterized the presence of anaglyphic crosstalk due to spectral issues on 13 LCD monitors, 14 plasma displays, and a CRT monitor when used with 25 different pairs of anaglyph 3-D glasses. A mathematical model was used to predict the amount of crosstalk in anaglyphic 3-D images when different combinations of displays and glasses are used, and therefore highlight displays, glasses, and combinations thereof which exhibit lower levels of crosstalk when displaying anaglyphic 3-D images.
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Characterizing crosstalk in anaglyphic stereoscopic images on LCD monitors and
plasma displays
Andrew J. Woods
Ka Lun Yuen
Kai S. Karvinen
Abstract
— In 1853, William Rollman1develop ed the inexpensive and easy to use anaglyph method
for displaying stereoscopic images. Althou gh it can be used with nearly any type of full-color display,
the anaglyph method compromises the accuracy of color reproduction, and it often suffers from cros-
stalk (or ghosting) between the left- and right-eye image channels. Crosstalk degrades the ability of
the observer to fuse the stereoscopic image, and hence reduces the quality of the 3-D image. Crosstalk
is present in various levels with most stereoscopic displays; however, it is often particularly evident
with anaglyphic 3-D images. This paper summarizes the results of two projects that characterized the
presence of anaglyphic crosstalk due to spectral issues on 13 LCD monitors, 14 plasma displays, and
a CRT monitor when used with 25 different pairs of anaglyph 3-D glasses. A mathematical model was
used to predict the amount of crosstalk in anaglyphic 3-D images when different combinations of
displays and glasses are used, and therefore highlight displays, glasses, and combinations thereof
which exhibit lower levels of crosstalk when displaying anaglyphic 3-D images.
Keywords Anaglyph, 3-D, stereoscopic, crosstalk, ghosting, LCD monitors, plasma displays, CRT
displays.
1 Introduction
The anaglyph method of displaying stereoscopic images
uses a complementary color-coding technique to send sepa-
rate left and right views to an observer’s two eyes. The two
perspective images of a stereo-pair are stored in comple-
mentary color channels of the display, and the observer
wears a pair of glasses containing color filters which act to
passthecorrectimagebutblocktheincorrectimagetoeach
eye.
For example, if a red/cyan anaglyph is used, the left
perspective image is stored in the red color channel and the
right perspective image is stored in the blue and green color
channels (blue + green = cyan), and the observer wears a
pair of anaglyph 3-D glasses with the left-eye filter red and
the right-eye filter cyan.
The main advantages of the anaglyph 3-D method are
its simplicity, low cost, and compatibility with any full-color
display. The main disadvantages are its inability to accu-
rately depict full-color images, and commonly the presence
of crosstalk. Crosstalk (or ghosting) is the leaking of an
image to one eye when it is intended exclusively for the
other eye. For example, the left eye should only be able to
see the left perspective image, but due to crosstalk, the left
eye may see a small proportion of the right perspective
image. Crosstalk occurs with most stereoscopic displays and
results in reduced image quality and difficulty of fusion if
the amount of crosstalk is large.
This paper considers the two spectral contributors to
anaglyphic crosstalk: display spectral response and anaglyph
glasses spectral response. Two other possible contributors to
anaglyph ghosting, image compression and image encod-
ing/transmission,2are not explored in this paper.
Figure 1 provides an illustration of the process of cros-
stalk in anaglyph stereoscopic images due to spectral leak-
age (as illustrated for the red/cyan method). Firstly, the
display has a specific spectral output for the red, green, and
blue color channels. Usually the left perspective image is
stored in the red color channel and the right perspective
image is stored in the green and blue color channels (cyan).
Second, the red/cyan anaglyph 3-D glasses used to view the
anaglyph display also have a certain spectral transmission
response for the left and right eye filters. Here the left filter
predominantly transmits red light but with a little bit of
transmission in the green band, and the right filter predomi-
nantly transmits blue and green light but with a little bit of
transmission in the red band. Due to the non-ideal nature of
the display and the glasses, some light from the right (cyan)
color channel leaks through the left (red) eye filter. Simi-
larly, some light from the left (red) color channel leaks. This
is in addition to the transmission of the intended image
through the left- and right-eye filters. Therefore, the left
eye predominantly sees the left perspective image but with
a small amount of the right perspective image visible, and
the right eye predominantly sees the right perspective
image but with a small amount of the left perspective image
visible.
This paper carries on from the work of Woods and
Rourke2which considered anaglyph ghosting with cathode-
ray tube (CRT) monitors, one liquid-crystal display (LCD)
monitor, and a mixture of LCD and digital light processing
(DLP) projectors. This paper focuses on anaglyph ghosting
on LCD monitors and plasma displays with 13 LCD moni-
The authors are with the Centre for Marine Science & Technology, Curtin University of Technology, GPO Bo x U1987, Perth, WA 6845 Australia;
telephone +61-8-9266-7920, fax –4799, e-mail: A.Woods@cmst.curtin.edu.au.
©Copyright 2007 Society for Information Display 1071-0922/07/1511-0889$1.00
Journal of the SID 15/11,2007 889
Andrew J. Woods, Ka Lun Yuen, and Kai S. Karvinen, “Characterizing crosstalk in anaglyphic stereoscopic images on LCD monitors and plasma
displays” in Journal of the Society for Information Display, Volume 15, Issue 11, pp. 889-898, November 2007. www.3d.curtin.edu.au
tors and 14 plasma-displays panels (PDPs) tested. A CRT
monitor was also tested for comparison purposes. All data
for this project was measured using more accurate equip-
ment than was available in the previous study.2
This paper only examines crosstalk in red/cyan ana-
glyph stereoscopic images, although the simulation methods
discussed could also be applied to blue/yellow or green/
magenta anaglyphs.
2 Experimental method
The first step was to measure the spectral output of the dis-
plays using a manually calibrated Ocean Optics USB2000
spectroradiometer. Table 1 itemizes the displays tested –
consisting of 13 LCD computer monitors, 14 PDPs, and one
CRT monitor.
Each display was connected to a PC which displayed a
slide show consisting of a plain white slide (R = G = B =
255), a plain red slide (R = 255, G = B = 0), a plain green
slide (R = B = 0, G = 255), a plain blue slide (R = G = 0, B
= 255), and a plain black slide (R = G = B = 0). The spec-
troradiometer was used to measure the spectrum of each of
these slides (as displayed on each display) and the data col-
lected on a PC.
The second step was to measure the transmission
spectrum of a large selection of anaglyph 3-D glasses using
a PG Instruments T90+ UV/Vis spectrophotometer. A total
of 50 pairs of anaglyph glasses were tested3; however, only
25 pairs are reported here for the sake of brevity.
The third step was to use a specially developed Matlab
computer program to calculate the presence of crosstalk in
the anaglyph images for different display and glasses combi-
nations. With reference to Fig. 1, the program first loads
and resamples the display and filter spectral data so that all
data is on a common x-axis coordinate system. Next, the pro-
gram determines the display’s cyan spectral output by add-
ing the green and blue color channel data of the display. The
program then multiplies the red display spectrum with the
red filter’s spectral response to obtain the intended image
curve for the red eye, multiplies the cyan display spectrum
with the cyan filter’s spectrum to obtain the intended image
curve for the cyan eye, multiplies the red display spectrum
with the cyan filter’s spectral response to obtain the crosstalk
curve for the cyan eye, and multiplies the cyan display spec-
trum with the red filter’s spectrum to obtain the crosstalk
curve for the red eye.
The program also scales these result curves to include
the human-eye response to light by multiplying by the curve
shown in Fig. 2, which shows the CIE (International Com-
mission on Illumination) model for simulating photopic
(bright light) human-eye sensitivity to light.4
The crosstalk percentage for each eye is then calcu-
lated by dividing the area under the crosstalk curve by the
area under the intended signal curve for each eye and mul-
tiplying by 100. The overall crosstalk factor for a particular
FIGURE 1 — Illustration of the process of anaglyph spectral ghosting
and its simulation in this project. From the top: (1) Spectral response of
display, (2) spectral response of anaglyph glasses, (3) simulation of
ghosting using a computer program, (4) spectral output characteristic of
crosstalk and intended image, and (5) visual illustration of left- and
right-eye view with crosstalk.
TAB LE 1 Listing of the tested displays.
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Woods et al. /
Characterizing anaglyph crosstalk on LCD monitors and plasma displays
pair of glasses in combination with a particular display is the
sum of the left- and right-eye percentage crosstalk values. It
should be noted that the overall crosstalk factor is not a per-
centage, but rather a number that allows the comparison of
different glasses/display combinations. The program also
automates the process of performing a cross comparison of
all the displays against all of the glasses.
3Results
3.1 Display device results
The spectral output measurement of 13 different LCD
monitors, 14 different PDP monitors, and one CRT monitor
are reported in this study.
Figure 3 shows the spectral output of an example
LCD monitor (LCD04). All of the LCD monitors tested
used cold cathode fluorescent lamp (CCFL) backlights.
CCFLs are a form of mercury-vapor fluorescent lamp that
generate visible light by energizing the gas in the fluores-
cent tube so that it emits ultraviolet rays which in turn
causes the phosphor material that coats the inside surface of
the tube to emit visible light. The spectrum of a CCFL is
fairly broad but with many notable narrow peaks. Although
the spectral output of the raw CCFL was not measured in
any of the LCDs tested, its general form can be approxi-
mated from the summation of the three traces shown in
Fig. 3. The three individual color primaries (red, green, and
blue) are created by placing color filters over the individual
subpixel groups in the LCD pixel grid.5The light spectrum
output by each color channel is primarily a multiplication of
the backlight spectrum by the spectrum of the color filters
used in each subpixel. In the example LCD monitor shown
in Fig. 3, there is a considerable amount of overlap between
each of the three color channels. The amount of overlap
varied from monitor to monitor.
The combined spectral results for the 13 LCD moni-
tors tested are shown in Appendix B (Figs. B1, B2, and B3).
A separate graph is provided for each of the three color pri-
maries. There is a lot of similarity between the spectral
characteristics of all the LCD monitors; however, some dif-
FIGURE 2 CIE 1931 standard normalized photopic human-eye
response.
FIGURE 3 Color spectrum of an example LCD monitor (LCD04).
FIGURE 4 Color spectrum of an example plasma display (PDP08).
FIGURE 5 Color spectrum of the example CRT monitor.
Journal of the SID 15/11,2007 891
ferences occur in the out-of-band rejection (e.g., the
amount of green light present in the red color primary)
which will probably be related to the quality of color filters
usedforeachofthecolorprimaries.
Figure 4 shows the spectral output of an example
plasma display (PDP08). Color plasma displays generate vis-
ible light by energizing a gas mixture in each cell so that it
emits ultraviolet light rays which in turn causes the phos-
phor material that coats the inside of each cell to emit visible
light. The spectral output of each of the color channels is
determined by the phosphor formulation used for each
group of subpixels.6The blue output has a classic bell-
shaped curve centered around 450 nm. The red output is a
mixture of several narrow peaks and the green output is a
mixture of a bell curve and another major narrow peak.
The combined spectral results for all of the 14 plasma
displays tested are shown in Appendix B (Figs. B4, B5, and
B6). A separate graph is provided for each of the three color
primaries. The color spectrum of the red and blue color pri-
maries are very similar across all the tested plasma displays;
however, there is a lot of variation of the spectral response
of the green color primary which will probably relate to the
formulation of the phosphors used.
Figure 5 shows the spectral output of an example CRT
monitor. A previous paper by Woods and Tan7reported that
11 tested CRT monitors had almost exactly the same spec-
tral response which suggests that most CRTs use the same
phosphor formulation for each of the color primary chan-
nels. The blue and green output have a bell-shaped curve
whereas the red output is made up of several narrow peaks.
3.2 Anaglyph 3-D glasses results
Figure 4 shows the spectral transmission of an example pair
of red-cyan anaglyph glasses. In this example the red filter
has a pass band of wavelengths roughly 600–700 nm. The
cyan filter has a pass band of wavelengths roughly 550–400
nm. As can be seen in Fig. 4, a little bit of light at the wave-
length of around 590 nm will be transmitted through both
the red and cyan filters, therefore arriving at both eyes.
When this overlap occurs it is anotherpossiblesourceof
crosstalk.
All of the anaglyph glasses reported in this paper are
listed in Table 2. This list is substantially similar to that
reported in Woods and Rourke2except that all pairs of
glasses have been retested using a more accurate instru-
ment.
The spectral transmission of all the glasses from Table
2areshownoverlaidinFig.7(redfilters)andFig.8(cyan
filters). It can be seen that there is considerable variation
between the spectral response of the various glasses tested.
There is some clustering of some of the data, however, this
is probably due to some glasses being from the same manu-
facturer or manufacturing process.
3.3 Crosstalk calculation results
The crosstalk and uncertainty results calculated by the Mat-
lab program for the combination of all displays against all
anaglyph glasses are shown in Tables C1 and C2 in Appendix
C. For each display/glasses combination, the table lists the
percentage crosstalk for the red eye (top left), the percent-
age crosstalk for the cyan eye (top right), and the overall
crosstalk factor for both eyes combined (bottom). The over-
all crosstalk factor is the sum of the left- and right-eye per-
centages, and as such is not a percentage. The uncertainty
figures are only shown for the overall crosstalk factor. The
uncertainty figures were calculated for the individual red
and cyan crosstalk but are omitted here due to space limita-
tions.
3.4 Validation test
A first-order validation test was performed to confirm that
the results from the crosstalk model were sensible. A set of
FIGURE 6 — Spectral transmission of an example pair of anaglyph 3-D
glasses (3DG16).
FIGURE 7 Spectral transmission for all the red filters.
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Woods et al. /
Characterizing anaglyph crosstalk on LCD monitors and plasma displays
test images were viewed on a CRT monitor and subjectively
ranked in order of increasing crosstalk. The results of the
subjective ranking were then compared with the crosstalk
ranking generated by the MATLAB program and this is
showninTable2.
As can be seen from the table, the subjective ranking
agrees extremely well with the calculated results, which pro-
vides some confidence in the validity of the crosstalk calcu-
lation results. Two of the differences occurred where the
crosstalk percentage difference was just 0.1, and two differ-
ences occurred where the crosstalk percentage difference
was 0.4. Crosstalk differences of 0.1 and 0.4 are very small
and are hard to discern by the naked eye.
4Discussion
Crosstalk in anaglyph images acts to degrade the 3-D image
quality by making them hard to fuse. One important way to
optimize the quality of anaglyph 3-D images is therefore to
minimize the presence of crosstalk. In most circumstances,
the easiest way to minimize crosstalk would be with the
choice of anaglyph 3-D glasses, but in some circumstances
it may also be possible to choose different display monitors.
This project aims to highlight possible low-crosstalk combi-
nations so crosstalk can be reduced.
Across all of the displays, the LCD monitors had the
lowest overall crosstalk, both from an average (18.6) and also
a global minimum (7.0) perspective. The plasma displays were
very close behind with an average overall crosstalk of 18.6
and global minimum of 8.1. The CRT had much worse ana-
glyph crosstalk with an average overall crosstalk of 27.0 and
global minimum of 18.2. On average, the CRT had 45%
more crosstalk than the LCD and plasma displays.
As cited earlier, there is a reasonable amount of vari-
ation of the color spectrum across all LCD monitors and
across all plasma displays. Similarly, there is a fairly large
variation in overall crosstalk factor across all of the LCD
monitors and all of the plasma displays. For example, the
LCD monitor with the highest crosstalk factors (LCD04)
only performs marginally better than a CRT, and the plasma
display with the highest crosstalk factors (PDP02) had
slightly worse performance than a CRT.
The best performing LCD monitor was LCD14 which
provided an average crosstalk factor of only 13.8 and
achieved the lowest crosstalk factor across all displays of 7.0
(when combined with glasses 3DG32). The best performing
plasma display was the PDP12 with an average crosstalk fac-
tor of 11.9 which achieved the third lowest crosstalk factor
across all plasma displays of 8.1 (when used with glasses
3DG13).
The worst pair of anaglyph glasses across all displays
by far was 3DG28 – the ink-jet-printed transparency filters.
This is not an unexpected result since these filters have such
poor performance in the out-of-band wavelengths and very
poor contrast.
The choice of best glasses depends upon which display
is being considered. For the LCD monitors, 3DG32,
3DG26, and 3DG13 usually had the lowest overall crosstalk
(all were within the uncertainty limits of each other). For
the plasma displays, 3DG30, 3DG13, and 3DG32 usually
TABLE 2 — Subjective testing of anaglyph glasses and comparison with
calculated results. Lines join matching entries.
FIGURE 8 Spectral transmission for all the cyan filters.
Journal of the SID 15/11,2007 893
had the lowest overall crosstalk (within the uncertainty lim-
its). For the CRT case, the best glasses were 3DG32,
3DG26, and 3DG13. It is interesting to note that the “cyan”
filters of 3DG13 and 3DG26 haveamoreblueappearance
than those of 3DG30 and 3DG32 that have a more cyan
appearance. These differences may have some effect on
color perception which is discussed below.
As can be seen in Tables C1 and C2, red crosstalk is
usually significantly greater than cyan crosstalk – on average
almost four times greater. Red crosstalk usually therefore
dominates the overall crosstalk value. This can be attributed
to the shape of the spectral curves for the display and
glasses, but will also be due to the fact that the green chan-
nel is usually much brighter than the red channel.
It is usually possible to obtain a slightly lower overall
crosstalk figure for a particular display by mixing and match-
ing filters from different glasses; however, the improvement
achieved is usually less than the calculated overall uncer-
tainty value.
It is worth mentioning that even a perfect filter (one
that transmits 100% of light in the desired wavelength
domain and 0% outside it) would still have crosstalk if the
display’s color channels overlap in the spectral domain (as
most displays do).
Three further items are worth considering. First,
intensity. If the filter cuts out most of the light, the image
will be very dim and hard to see. Lower light levels also
make the effect of even small ghosting levels proportionally
greater than they might otherwise be. A brightness imbal-
ance between left and right eye can also result in the Pul-
frich effect8whereby horizontal motion can be interpreted
as binocular depth, which is generally undesirable. Bright-
ness levels and imbalance have not been considered in this
paper.
Second, color perception. Truly full-color stereoscopic
images are not possible with anaglyphs, but a properly con-
structed anaglyph using complimentary colors can approxi-
mate a full-color image. This distorted color image is usually
referred to as a “pseudo-color anaglyph” or a “polychromatic
anaglyph” as opposed to a “full-color anaglyph” (which is not
possible). If a non-complimentary combination is used (e.g.,
red/blue or red/green), pseudo-color anaglyphs are impossi-
ble because a large portion of the visible spectrum is miss-
ing. The overall image may also be darker. This paper has
only considered red/cyan anaglyphs, although it is some-
times hard to draw a line between what is classified as a cyan
filter and what is classified as a blue filter.
Third, color balance and color temperature. Most
monitors allow the color balance or color temperature of the
display to be adjusted. This allows the user to change the
relative intensities of the three color channels (but not the
spectral output of each color channel). We have found that
such adjustments do affect the results of the crosstalk calcu-
lations; however, as yet we have not used this knowledge to
choose an optimum color balance, or performed any valida-
tion experiments to confirm whether the simulation of color
balance changes matches human perception. For the pur-
poses of this study, the default color profiles were used for
each monitor.
5 Conclusion
Although there are a range of stereoscopic display technolo-
gies available that produce much better 3-D image quality
than the anaglyph 3-D method, the anaglyph remains widely
used because of its simplicity, low cost, and compatibility
with all full-color displays. This paper highlights one par-
ticular way of improving the image quality of anaglyph 3-D
images specifically relating to spectral crosstalk.
This study has revealed that crosstalk in anaglyphic
3-D images can be minimized by the appropriate choice of
anaglyphic 3-D glasses. The study has revealed that there
can be considerable variation in the amount of crosstalk pre-
sent when an anaglyphic 3-D display is viewed with differ-
ent anaglyphic 3-D glasses.
The study has also revealed that there is considerable
variation in the amount of anaglyphic crosstalk exhibited by
different displays. For example, on average CRT monitors
exhibit approximately 45% more crosstalk than LCD moni-
tors and plasma displays.
An anaglyphic crosstalk calculation algorithm has been
developed that appears to work well and generates outputs
that agree well with subjective assessments of anaglyphic
3-D crosstalk.
It should be noted that the results of this paper are not
intended to be a leader board of one glasses manufacturer
versus another – we have not tested all glasses from all
manufacturers, nor have we tested a large sample of each
manufacturers glasses. This paper does, however, highlight
that there is significant variation between different ana-
glyph 3-D glasses and displays. Further crosstalk optimiza-
tion may be possible by using the anaglyphic crosstalk
calculation algorithm and working with 3-D glasses manu-
facturers.
Acknowledgments
We would like to thank the multitude of companies and
individuals who lent LCD monitors and plasma displays for
testing.3,9 We also wish to thank iVEC (the hub of advanced
computing in Western Australia) and Jumbo Vision Interna-
tional for their support of the plasma displays phase of this
project.
References
1 R Zone, “Good old fashion anaglyph: High tech tools revivea classic format
in spy kids 3-D,” Stereo World 29, No. 5, 11–13 and 46 (2002–2003).
2 A J Woods and T Rourke, “Ghosting in anaglyphic stereoscopic im-
ages,” Stereoscopic Displays and Virtual Reality Systems XI, Proc SPIE
5291, 354–365 (2004).
3 K S Karvinen and A J Woods, “The compatibility of plasma displays
with stereoscopic visualization,” Technical Report CMST2007-04 (Cur-
tin University of Technology, Australia, 2007).
894
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Characterizing anaglyph crosstalk on LCD monitors and plasma displays
4CIE,Commission Internationale de l’Eclairage Proceedings (Cam-
bridge University Press, 1932).
5 B A Wandell and L D Silverstein, “Digital color reproduction,” The
Science of Color (Elsevier, 2003), pp. 296.
6 H Uchiike and T Hirakawa, “Color plasma displays,” Proc IEEE 90,
Issue 4, 533–539 (2002).
7 A J Woods and S S L Tan, “Characterizing sources of ghosting in
time-sequential stereoscopic video displays,” Stereoscopic Displays
and Virtual Reality Systems IX, Proc SPIE 4660, 66–77 (2002).
8 C Pulfrich, “Die Stereoskopie im Dienste der isochromem und
herterochromen Phot ometrie,” Naturwissenschaft 10, 553–564 (1922).
9 K L Yuen, “Compatibility of LCD monitors with stereoscopic display
methods,Undergraduate Student Project Report (Curtin University
of Technology, 2006).
Appendix A:
Red/cyan anaglyph glasses
Appendix B:
Spectral results for all tested
LCD monitors and plasma displays
The figures below show the spectral results for each color
channel of all tested LCD monitors and plasma displays.
Figure B1 is normalized on the average value between 450
and 455 nm. Figures B2 and B3 are normalized on the peak
value. Figures B4–B6 are normalized on the area under the
TAB LE A1 — Red/cyan anaglyphic 3-D glasses measured.
Journal of the SID 15/11,2007 895
curve. These normalizations were chosen so as to more eas-
ily reveal the similarities and differences between the vari-
ous traces.
FIGURE B1 — Blue-color-primary spectral output for 13 LCD monitors.
FIGURE B2 Green-color-primary spectral output for 13 LCD monitors.
FIGURE B4 Blue-color-primary spectral ou tput for 14 plasma displays.
FIGURE B3 Red-color-primary spectral output for 13 LCD monitors.
FIGURE B5 Green-color-primary spectral output for 14 plasma
displays.
FIGURE B6 Red-color-primary spectral output for 14 plasma displays.
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Woods et al. /
Characterizing anaglyph crosstalk on LCD monitors and plasma displays
Appendix C:
Crosstalk calculation results for
LCD monitors and plasma displays
The following tables contain the results from the crosstalk
calculation program. Every combination of anaglyph glasses
and display has been calculated. The lowest overall crosstalk
combinations are highlighted in bright green and the worst
overall crosstalk results are highlighted in orange. Overall
crosstalk results of less than 15 have been highlighted in
light green. Red crosstalk percentages less than nine have
been highlighted in pink, and cyan crosstalk percentages
less than 1.5 have been highlighted in cyan. These threshold
figures do not have any significance apart from allowing us
to highlight the lower crosstalk results.
TAB LE C1 — Crosstalk calculation results for the LCD and CRT monitors. The top left cell of each combination is red crosstalk %, the top right cell of
each combination is cyan crosstalk %, and the bottom cell of each combination is the overall crosstalk factor and uncertainty.
Journal of the SID 15/11,2007 897
Andrew J. Woods is a research engineer with the
Centre for Marine Science and Technology at Cur-
tin University of Technology, Perth, Australia. He
received his MEng and BEng (Hons1) degrees in
electronics engineering and has nearly 20 years
experience in the design, application, and evaluation
of stereoscopic imaging solutions for teleopera-
tion, industrial, and entertainment applications.
He is co-chair of the annual Stereoscopic Dis-
plays and Applications Conference (since 2000)
and in 2005 was co-chair of the annual Electronic Imaging: Science &
Technology Symposium.
Ka Lun Yuen is a graduate of Curtin University of
Technology with a double bachelors degree in
physics and education.
Kai S. Karvinen is currently completing a double
bachelors degree in physics and electrical engi-
neering at Curtin University of Technology and is
a tutor in the Department of Electrical Engineering
at Curtin University of Technology.
TAB LE C2 Crosstalk calculation results for the plasma displays. The top left cell of each combination is red crosstalk %, the top right cell of each
combination is cyan crosstalk %, and the bottom cell of each combination is the overall crosstalk factor and uncertainty.
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Woods et al. /
Characterizing anaglyph crosstalk on LCD monitors and plasma displays
... In Experiments 1-6, a mirror stereoscope was used for dichoptic stimulation ( Figure 1C). Mirror stereoscopes are characterized by the absence of crosstalk, or "ghosting," where images intended for one eye are faintly visible to the other eye (Baker, Kaestner, & Gouws, 2016;Woods, Yuen, & Karvinen, 2007). To maximize statistical power, we reanalyzed data across Experiments 1-4 and 6, in which the primes were invisible and dichoptic crosstalk was zero. 3 Mean RT in the category task was 637 ms in trials with elongated primes, and 634 ms in trials with nonelongated animal 3 Crosstalk is zero for mirror stereoscopes if the two images are optically segregated at all stages of presentation (e.g., by using two monitors in combination with viewing tunnels). ...
... Anaglyph glasses were used in the original masked priming studies (Almeida et al., 2008(Almeida et al., , 2010(Almeida et al., , 2014Sakuraba et al., 2012), as well as in the fMRI study showing preserved dorsal stream activity to elongated tools during CFS (Fang & He, 2005). In contrast to mirror stereoscopes, or setups with cardboard dividers (Schurger, 2009), anaglyph glasses are associated with substantial crosstalk (Baker et al., 2016;Woods et al., 2007). To investigate masked priming in the presence of crosstalk, we conducted Experiment 7 as a repetition of Experiment 6 with anaglyph glasses for dichoptic stimulation. ...
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The study of nonconscious priming is rooted in a long research tradition in experimental psychology and plays an important role for a range of topics, including visual recognition, emotion, decision making, and memory. Prime stimuli can be transiently suppressed from awareness by using a variety of psychophysical paradigms. The aim is to understand which stimulus features can be processed nonconsciously and influence behavior toward subsequently presented probe stimuli. Here, we tested the notion that continuous flash suppression (CFS), a relatively new method of interocular suppression, selectively disrupts stimulus identification mediated by the ventral “vision-for-perception” pathway, while preserving action-relevant stimulus features processed by the dorsal “vision-for-action” pathway. Given the far-reaching implications of this notion for the influential two visual systems hypothesis, and visual cognition in general, we investigated its empirical basis in a series of seven masked priming experiments using CFS. We did not find evidence for nonconscious priming of object categorization by action-relevant features. Based on these results, we recommend skepticism about the notion that the processing of action-relevant features under CFS is selectively preserved in the “vision-for-action” pathway. Second, we conclude that CFS experiments are less informative than approaches using visible stimuli, when the aim is to gather data in relation to the two visual systems hypothesis. Third, we propose that future nonconscious priming studies should carefully consider the position of suppression paradigms within a functional hierarchy of unconscious processing, thus constraining hypothesis generation to effects that are plausible given the employed methodology.
... Spectral luminance of an LCD monitor[14] ...
Conference Paper
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Liquid Crystal Displays (LCDs) were tested byphotometric means using two techniques: the usual one-pointmeasuring technique and, more detailed, two-hundred-pointtechnique proposed by the authors. Inspection of the LC unitswas conducted while test images (white, RGB and chesspatterned black and white) were displayed, to analyzedistribution of luminance more precisely. Results of analysis are qualitatively compared to proposed lightning level standards and recommendations to prolong the lifespan of the LCD unit is give.
... For the optokinetic response, the green light emitted from the monitor peaks at 550 nm [30]. This is closer to the larval red opsin spectral peak of 556 nm than green opsin at 461 nm, so although humans perceive the 550-nm stimulus as green using 535-nm peaking M cones [31] it actually best activates red opsin in larval zebrafish [18]. ...
Article
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We investigate mutations in trβ2, a splice variant of thrb, identifying changes in function, structure, and behavior in larval and adult zebrafish retinas. Two N-terminus CRISPR mutants were identified. The first is a 6BP+1 insertion deletion frameshift resulting in a truncated protein. The second is a 3BP in frame deletion with intact binding domains. ERG recordings of isolated cone signals showed that the 6BP+1 mutants did not respond to red wavelengths of light while the 3BP mutants did respond. 6BP+1 mutants lacked optomotor and optokinetic responses to red/black and green/black contrasts. Both larval and adult 6BP+1 mutants exhibit a loss of red-cone contribution to the ERG and an increase in UV-cone contribution. Transgenic reporters show loss of cone trβ2 activation in the 6BP+1 mutant but increase in the density of cones with active blue, green, and UV opsin genes. Antibody reactivity for red-cone LWS1 and LWS2 opsin was absent in the 6BP+1 mutant, as was reactivity for arrestin3a. Our results confirm a critical role for trβ2 in long-wavelength cone development.
... For the optokinetic response, the green light emitted from the monitor peaks at 550 nm [30]. This is closer to the larval red opsin spectral peak of 556 nm than green opsin at 461 nm, so although humans perceive the 550-nm stimulus as green using 535-nm peaking M cones [31] it actually best activates red opsin in larval zebrafish [18]. ...
Preprint
Full-text available
We investigate a splice variant of thrb isolated in the retina, trβ2 , identifying functional changes in larval and adult mutant zebrafish lacking trβ2. We constructed two CRISPR mutant zebrafish with mutations located in the N-terminus region. The first is a 6BP + 1 insertion deletion frameshift resulting in a truncated protein. The second is a 3BP in frame deletion with intact binding domains. ERG recordings showed that the 6BP + 1 mutants did not respond to red wavelengths of light while the 3BP mutants did respond. 6BP + 1 mutants lacked optomotor and optokinetic responses to red/black and green/black contrasts. Adult 6BP + 1 mutants exhibit a loss of red-cone contribution to the ERG, and an increase in green and UV contributions. Anatomical markers show loss of red-cones in the 6BP + 1 mutant but increase in blue, green, and UV cone density. Our results confirm trβ2 ’s role in retinal cone development. Author Summary There are four cone photoreceptors responsible for color vision in zebrafish: red, green, blue, and UV. The thyroid hormone receptor trβ2 is localized in the vertebrate retina. We know that it is necessary for the development of long-wavelength-sensitive cones (red), but here we investigate the functional alterations that accompany a loss of trβ2 . Our work contributes to the ongoing investigations of retinal development and the involvement of thyroid hormone receptors. Confirming previous morphological findings, we see that the fish become red colorblind when trβ2 is knocked out, but the contributions of the other three cone types shift in response. Our work highlights the plasticity of the retinal circuit as we see changes in opsin peaks and cone sensitivity, increases in contributions of UV cones, and an attempt at a mosaic pattern in the adult retina all in the absence of trβ2 and red cones. We now have an increased understanding of mechanisms underlying retinal development
... Measurement of the luminous flux density was carried out using an Extech EA33 EasyView light meter, while the form of the spectrum was recorded by an Ocean Optics USB 2000+ spectrometer. Estimation of the radiant flux density from these measurements was achieved through use of the CIE standard photopic luminous efficacy function [148][149][150][151] ; further details regarding this calculation and the measured form of the LED spectrum are provided by Fig. S3 of the Supplementary Information and the accompanying discussion. ...
Article
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Through a facile solvothermal procedure, a CdS/WOx nanocomposite has been synthesised which exhibits photocapacitive behaviour under white light illumination at a radiant flux density of 99.3 mW cm−2. Photoelectrochemical experiments were undertaken to examine the self-charging properties of the material and to develop an understanding of the underlying electronic band structure responsible for the phenomenon. By employing XPS, UPS and UV-Vis diffuse reflectance spectroscopy for further characterisation, the ability of the composite to generate current following the removal of incident light was related to the trapping of photoexcited electrons by the WOx component. The presence of WOx yielded an order of magnitude increase in the transient photocurrent response relative to CdS alone, an effect attributed to the suppression of electron-hole recombination in CdS due to hole transfer across the CdS/WOx interface. Moreover, current discharge from the material persisted for more than twenty minutes after final illumination, an order of magnitude improvement over many existing binary composites. As a seminal investigation into the photocapacitive characteristics of CdS/WOx composites, the work offers insight into how the constituent materials might be utilised as part of a future self-charging solar device.
... From the values represented in Fig 4E and Fig. 4F, the crosstalk, computed as the ratio between the "leakage" and the signal (x 100), in our experimental setup was 6.96% for the red channel, and 9.07% for the cyan channel. Thus, the amount of light that leaks from one stereoscopic image channel to another was very low [22]. ...
Article
We present a new application for iPad for screening stereopsis at multiple distances that allows testing up to ten levels of stereoacuity at each distance. Our approach is based on a random dot stereogram viewable with anaglyph spectacles. Sixty-five subjects with no ocular diseases, wearing their habitual correction were measured at 3 m and 0.5 m. Results were compared with a standard stereoscopic test (TNO). We found not statistically significant differences between both tests, but our method achieved higher reproducibility. Applications in visual screening programs and to design and use of 3D displays, are suggested.
... In numerous studies, binocular separation has been achieved using plastic colored filters (usually red for one eye and green or blue for the other) and tinting the stimuli in these colors. This anaglyph arrangement is notorious for causing substantial crosstalk (e.g., Woods, Yuen, & Karvinen, 2007), so it was included as a baseline condition. This system used the same Iiyama CRT display as an earlier system. ...
Article
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Studying binocular vision requires precise control over the stimuli presented to the left and right eyes. A popular technique is to segregate signals either temporally (frame interleaving), spectrally (using coloured filters) or through light polarization. None of these segregation methods achieves perfect isolation, and so a degree of ‘crosstalk’ is usually apparent in which signals intended for one eye are faintly visible to the other eye. Previous studies have reported crosstalk values mostly for consumer-grade systems. Here we measure crosstalk for eight systems, many of which are intended for use in vision research. We provide benchmark crosstalk values, report a negative crosstalk effect in some LCD-based systems, and give guidelines for dealing with crosstalk in different experimental paradigms.
Article
Electronic displays have become an integral part of life in the developed world since the revolution of mobile computing a decade ago. With the release of multiple consumer-grade virtual reality (VR) and augmented reality (AR) products in the past 2 years utilizing head-mounted displays (HMDs), as well as the development of low-cost, smartphone-based HMDs, the ability to intimately interact with electronic screens is greater than ever. VR/AR HMDs also place the display at much closer ocular proximity than traditional electronic devices while also isolating the user from the ambient environment to create a “closed” system between the user's eyes and the display. Whether the increased interaction with these devices places the user's retina at higher risk of damage is currently unclear. Herein, the authors review the discovery of photochemical damage of the retina from visible light as well as summarize relevant clinical and preclinical data regarding the influence of modern display devices on retinal health. Multiple preclinical studies have been performed with modern light-emitting diode technology demonstrating damage to the retina at modest exposure levels, particularly from blue-light wavelengths. Unfortunately, high-quality in-human studies are lacking, and the small clinical investigations performed to date have failed to keep pace with the rapid evolutions in display technology. Clinical investigations assessing the effect of HMDs on human retinal function are also yet to be performed. From the available data, modern consumer electronic displays do not appear to pose any acute risk to vision with average use; however, future studies with well-defined clinical outcomes and illuminance metrics are needed to better understand the long-term risks of cumulative exposure to electronic displays in general and with “closed” VR/AR HMDs in particular. [ Ophthalmic Surg Lasers Imaging Retina . 2018;49:346–354.]
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Las pruebas clínicas para evaluar la supresión están diseñadas generalmente para comprobar solamente su presencia. En este trabajo se evalúa la fiabilidad de la cuantificación de la supresión basada en contraste. Se utilizó una tarea dicóptica de discriminación de movimiento global con kinematogramas de puntos aleatorios, una técnica de codificación cromática basada en la división del espectro visible, para la construcción de la presentación dicóptica, y la variante de cuantificación que comprende una etapa binocular y otra dicóptica. Para determinar el desempeño se utilizó el método de la escalera. A pesar de las limitaciones del experimento, los resultados apoyan la teoría sobre la relevancia del desequilibrio de contraste intraocular en el proceso de la supresión, corroboran la fiabilidad de la cuantificación de la supresión basada en contraste y validan la viabilidad de la técnica cromática dicóptica.
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Creating realistic three-dimensional (3D) experiences has been a very active area of research and development, and this article describes progress and what remains to be solved. A very active area of technical development has been to build displays that create the correct relationship between viewing parameters and triangulation depth cues: stereo, motion, and focus. Several disciplines are involved in the design, construction, evaluation, and use of 3D displays, but an understanding of human vision is crucial to this enterprise because in the end, the goal is to provide the desired perceptual experience for the viewer. In this article, we review research and development concerning displays that create 3D experiences. And we highlight areas in which further research and development is needed. Expected final online publication date for the Annual Review of Vision Science Volume 2 is September 15, 2016. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.
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After decades of research and development, plasma displays are finally beginning to appear in the commercial and consumer markets. Following a short review on the basic principles of direct and alternating current plasma displays, we present a summary of the status of color plasma displays. Plasma display panels (PDPs) have finally achieved luminance and efficiency values on par with hi-definition cathode ray tube monitors. Additional improvements in performance will open up a new world of large PDP displays. Ultimately, what will drive the PDP market will be continued improvements in the performance of color PDPs themselves. PDP makers are working on reducing power consumption through improved luminous efficiency and improved component materials and manufacturing methods of color PDPs. With improvements in the cell structure and driving methods, there is a good prospect of achieving a luminous efficiency of 2-3 lm/W and a power consumption of about 200 W for 50-in diagonal size
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Anaglyphic 3D images are an easy way of displaying stereoscopic 3D images on a wide range of display types, eg. CRT, LCD, print, etc. While the anaglyphic 3D image method is cheap and accessible, its use requires a compromise in stereoscopic image quality. A common problem with anaglyphic 3D images is ghosting. Ghosting (or crosstalk) is the leaking of an image to one eye, when it is intended exclusively for the other eye. Ghosting degrades the ability of the observer to fuse the stereoscopic image and hence the quality of the 3D image is reduced. Ghosting is present in various levels with most stereoscopic displays, however it is often particularly evident with anaglyphic 3D images. This paper describes a project whose aim was to characterise the presence of ghosting in anaglyphic 3D images due to spectral issues. The spectral response curves of several different display types and several different brands of anaglyph glasses were measured using a spectroradiometer or spectrophotometer. A mathematical model was then developed to predict the amount of crosstalk in anaglyphic 3D images when different combinations of displays and glasses are used, and therefore predict the best type of anaglyph glasses for use with a particular display type.
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A common artefact of time-sequential stereoscopic video displays is the presence of some image ghosting or crosstalk between the two eye views. In general this happens because of imperfect shuttering of the Liquid Crystal Shutter (LCS) glasses used, and the afterglow of one image into another due to phosphor persistence. This paper describes a project that has measured and quantified these sources of image ghosting and developed a mathematical model of stereoscopic image ghosting. The primary parameters which have been measured for use in the model are: the spectral response of the red, green and blue phosphors for a wide range of monitors, the phosphor decay rate of same, and the transmission response of a wide range of LCS glasses. The model compares reasonably well with perceived image ghosting. This paper aims to provide the reader with an improved understanding of the mechanisms of stereoscopic image ghosting and to provide guidance in reducing image ghosting in time-sequential stereoscopic displays.
Article
This chapter discusses the principles of human vision that are used to design image capture and display devices. The chapter provides an overview of the properties of human vision that are essential in designing color-imaging technologies. It describes the application of these and related principles along with the specific technologies. Digital cameras and scanners are reviewed in this chapter. The chapter discusses displays with a particular emphasis on cathode ray tube (CRT) and liquid crystal display (LCD) technologies. The main focus is on the fundamental principles of color imaging technology that must be addressed in the design of capture and display technology. Quantitative methods useful for certain specific devices are described, and it is expected that these methods will be useful for future generations of display and capture technologies as well.
Compatibility of LCD monitors with stereoscopic display methods
  • K L Yuen
9 K L Yuen, “Compatibility of LCD monitors with stereoscopic display methods,” Undergraduate Student Project Report (Curtin University of Technology, 2006)
Good old fashion anaglyph: High tech tools revive a classic format in spy kids 3-D
  • R Zone
R Zone, "Good old fashion anaglyph: High tech tools revive a classic format in spy kids 3-D," Stereo World 29, No. 5, 11-13 and 46 (2002-2003).
The compatibility of plasma displays with stereoscopic visualization
  • K S Karvinen
  • A J Woods
K S Karvinen and A J Woods, "The compatibility of plasma displays with stereoscopic visualization," Technical Report CMST2007-04 (Curtin University of Technology, Australia, 2007).
  • Pulfrich