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[ACM Press the 16th ACM SIGGRAPH International Conference - Tokyo, Japan (2018.12.02-2018.12.03)] Proceedings of the 16th ACM SIGGRAPH International Conference on Virtual-Reality Continuum and its Applications in Industry - VRCAI '18 - Arriving light control for color vision deficiency compensation using optical see-through head-mounted display
摘要： Color vision deficiency (CVD), also known as color blindness, is commonly caused by genetic disorder. Unfortunately, as of 2018, there is not yet a cure for the condition. Contact lenses and glasses with color filter are possible solutions to CVD by applying uniform changes to user’s field of view (FoV). On the other hand, optical see-through head-mounted display (OST-HMD) can provide a controllable overlay to user’s FoV, which could help for making a better solution. To calibrate colors in FoV of a user with CVD, methods that often used, such as the daltonization process, need light reduce feature, which makes calibrated color darker. However, recent commercially available OST-HMDs don’t have a controllable way to decrease the brightness of incoming light. In this paper, we present an approach for light subtraction of OST-HMD using a transmissive LCD panel. A prototype system for achieving a controllable overlay to user’s FoV with OST-HMD by using scene camera, user-perspective camera, and the transmissive LCD panel was implemented.
关键词： augmented reality,head-mounted display,color vision deficiency,liquid crystal display
更新于2025-09-23 15:22:29
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Illumination discrimination in the absence of a fixed surface-reflectance layout
摘要： Previous studies have shown that humans can discriminate spectral changes in illumination and that this sensitivity depends both on the chromatic direction of the illumination change and on the ensemble of surfaces in the scene. These studies, however, always used stimulus scenes with a fixed surface-reflectance layout. Here we compared illumination discrimination for scenes in which the surface reflectance layout remains fixed (fixed-surfaces condition) to those in which surface reflectances were shuffled randomly across scenes, but with the mean scene reflectance held approximately constant (shuffled-surfaces condition). Illumination discrimination thresholds in the fixed-surfaces condition were commensurate with previous reports. Thresholds in the shuffled-surfaces condition, however, were considerably elevated. Nonetheless, performance in the shuffled-surfaces condition exceeded that attainable through random guessing. Analysis of eye fixations revealed that in the fixed-surfaces condition, low illumination discrimination thresholds (across observers) were predicted by low overall fixation spread and high consistency of fixation location and fixated surface reflectances across trial intervals. Performance in the shuffled-surfaces condition was not systematically related to any of the eye-fixation characteristics we examined for that condition, but was correlated with performance in the fixed-surfaces condition.
关键词： illumination perception,color vision,eye fixations,chromatic illumination discrimination
更新于2025-09-23 15:22:29
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Photoreceptor projection from a four-tiered retina to four distinct regions of the first optic ganglion in a jumping spider
摘要： Jumping spiders have four pairs of eyes (ocelli) of which only the principal eyes (PEs) are used to detect features of objects. Photoreceptors in the retina of the PEs form four layers (PL1-4) and terminate in the first optic ganglion (FOG). Here we focus on Hasarius adansoni because it has unique depth vision besides color vision and its FOG appears to contribute to the initial processing of these visual modalities. We first investigated the neuroanatomical organization of the FOG. The three-dimensional structure of the FOG revealed by synapsin immunostaining is horseshoe-shaped and consists of four terminal zones (TZ1-4). Then we traced single photoreceptors through serial sections and found that green-sensitive receptors of PL1 and 2 terminate in TZ1 and 2, respectively, by keeping retinotopic organization. In contrast to TZ1 and 2, TZ3 receives terminals of ultraviolet-sensitive receptors from lateral regions of both PL3 and 4, while photoreceptors of the medial region of PL3 and 4 terminate in TZ4. We further studied details of photoreceptor terminals and the branching pattern of interneurons in the FOG in Golgi stained preparations. Photoreceptors have long lateral processes in each terminal zone. Some photoreceptors terminating in TZ3 have branches innervating TZ1, indicating that TZ1 receives different spectral information. A type of interneuron connects TZ1 and 2, while others have branches within a single terminal zone or in the entire FOG. These results suggest that TZ1 and 2 contribute to color, shape, and depth vision, while TZ3 and 4 have specific roles for UV vision.
关键词： RRID:SCR_014305,vision,ocellus,depth vision,RRID:AB_528479,arthropods,color vision
更新于2025-09-23 15:21:01
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Modifying twisted nematic LCD screens to create dichromatic visual stimuli with LEDs
摘要： 1. The use of computers to create and display animations/videos in the study of visually-guided behaviors has been instrumental in understanding sensory mechanisms underlying complex traits. Using computer displays scientists are able to create a wide array of colors using three differently colored lights (Red, Green, Blue: RGB). While it is possible to generate scenes with RGB displays that mimic animals’ color perceptual experience, this can be problematic because it requires knowledge of the spectral absorbance of the animals’ photoreceptor classes, which are often unknown and are difficult to obtain. Even then, stimuli are limited to the central part of the visible spectrum (e.g., ultraviolet (UV) stimuli are not possible). 2. We present a cost-effective way of modifying a twisted nematic LCD screen that utilizes colored LEDs, that allows measuring animals’ sensitivity to, and discrimination between, wavelengths of light. It has the benefit of not requiring a-priori knowledge of animals’ photoreceptor classes. An LCD screen can be modified by removing the screen’s back polarizer (behind the liquid crystal layer) and backlighting the screen with LEDs of two different colors. One of the LED colors transmits through a polarizer with a transmission axis parallel to the screen’s front polarizer, and other LED color transmits through a polarizer orthogonal to the first. 3. To test color discrimination one can create a dichromatic stimulus in which both LED colors are ‘ON’ and the current fithrough one LED color is decreased, while the other is constant, which generated a maximum intensity contrast of 1.84 log units in our setup. To test color sensitivity one can create a monochromatic stimulus in which only one LED color is ‘ON’, which generates a contrast similar to the dichromatic stimulus. This technique overcomes many of the limitations of RGB-based LCD screens in a cost-effective way, and allows more accurate testing of the role of color in visually-guided behaviors. Besides the questions in vision research this setup can answer, it can also be used as an outreach tool in classrooms where children can learn about light, color, polarization, and technology.
关键词： twisted nematic LCD screen,spectral sensitivity,polarization,visually-guided behavior,color vision,spectrometer,LED
更新于2025-09-23 15:19:57
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Impact of Illumination Correlated Color Temperature, Background Lightness, and Painting Color Content on Color Appearance and Appreciation of Paintings
摘要： Lighting design for art exhibitions has a significant impact on the enjoyment and understanding of the displayed artworks. In particular, the selection of the light sources and the design of the museum space affect the visitors’ visual perceptions of the artworks and their color appearance. This project investigated some of the potential factors—the correlated color temperature (CCT) of the illumination, the overall color content of the painting and the lightness of its background—affecting a painting’s color appearance and appreciation in a museum setting. The study involved a survey conducted in the laboratory with both na?ve observers and lighting experts. The CCT of the lighting was found to be the main factor affecting the painting’s appearance and the observers’ overall preference for the lighting arrangements, whereas the overall hue content of the painting and the background lightness had a minor influence. Furthermore, it has been found that the perceived brightness increases along with the CCT.
关键词： paintings,Artworks illumination,CCT,visual perception,visual appreciation,color vision,museum lighting,background lightness,color appearance
更新于2025-09-19 17:15:36
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Photoreceptor Progenitors Depend Upon Coordination of <i>gdf6a</i> , <i>thrβ</i> , and <i>tbx2b</i> to Generate Precise Populations of Cone Photoreceptor Subtypes
摘要： PURPOSE. Replacing cone photoreceptors, the units of the retina necessary for daytime vision, depends upon the successful production of a full variety of new cones from, for example, stem cells. Using genetic experiments in a model organism with high cone diversity, zebrafish, we map the intersecting effects of cone development factors gdf6a, tbx2b, and thrb. METHODS. We investigated these genes of interest by using genetic combinations of mutants, gene knockdown, and dominant negative gene expression, and then quantified cone subtype outcomes (which normally develop in tightly regulated ratios). RESULTS. Gdf6a mutants have reduced blue cones and, discovered here, reduced red cones. In combined gdf6a/tbx2b disruption, the loss of gdf6a in heterozygous tbx2b mutants reduced UV cones. Intriguingly, when we disrupted thrb in gdf6a mutants by using a thrb morpholino, their combined early disruption revealed a lamination phenotype. Disrupting thrb activity via expression of a dominant negative thrb (dnthrb) at either early or late retinal development had differential outcomes on red cones (reduced abundance), versus UV and blue cones (increased abundance). By using dnthrb in gdf6a mutants, we revealed that disrupting thrb activity did not change gdf6a mutant cone phenotypes. CONCLUSIONS. Gdf6a loss directly affects blue and red cones and indirectly affects UV cones by increasing sensitivity to additional disruption, such as reduced tbx2b, resulting in fewer UV cones. The effects of thrb change through photoreceptor development, first promoting red cones and restricting UV cones, and later restricting UV and blue cones. The effects of gdf6a on UV, blue, and red cone development overlap with, but likely supersede, those of thrb.
关键词： BMP signaling,progenitor,color vision,retinal lamination,thyroid signaling,zebrafish,retinal development,determination,regeneration,cone photoreceptor
更新于2025-09-19 17:15:36
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Spectral tuning mediated by helix III in butterfly long wavelength-sensitive visual opsins revealed by heterologous action spectroscopy
摘要： Absorption spectra of opsin-based pigments are tuned from the UV to the red regions by interactions of the chromophore with surrounding amino acid residues. Both vertebrates and invertebrates possess long-wavelength-sensitive (LWS) opsins, which underlie color vision involving “red” sensing. The LWS opsins have independently evolved in each lineage, which suggests the existence of diverse mechanisms in spectral tuning. In vertebrate LWS opsins, the mechanisms underlying spectral tuning have been well characterized by spectroscopic analyses with recombinant pigments of wild type (WT) and mutant opsins. However in invertebrate LWS opsins including insect ones, the mechanisms are largely unknown due to the difficulty in obtaining recombinant pigments. Here we have overcome the problem by analyzing heterologous action spectra based on light-dependent changes in the second messenger in opsin-expressing cultured cells. We found that WTs of two LWS opsins of the butterfly, Papilio xuthus, PxRh3 and PxRh1 have the wavelengths of the absorption maxima at around 570 nm and 540 nm, respectively. Analysis of a series of chimeric mutants showed that helix III is crucial to generating a difference of about 15 nm in the wavelength of absorption maxima of these LWS opsins. Further site-directed mutations in helix III revealed that amino acid residues at position 116 and 120 (bovine rhodopsin numbering system) are involved in the spectral tuning of PxRh1 and PxRh3, suggesting a different spectral tuning mechanism from that of primate LWS opsins.
关键词： Red sensitivity,Rhodopsin,Color vision,Convergent evolution
更新于2025-09-19 17:13:59
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Functional Vision with X Chrome Lenses
摘要： Purpose: To implement x chrome lens in children Methods: A pilot, cross sectional study was performed in the tertiary eye centre during the period of 1 year. Functional vision like Visual Acuity, Contrast Sensitivity, Stereopsis and color vision of 10 existing x chrome soft contact lenses users were analyzed with and without lenses. Results: Visual functions were compared statistically using paired t test with SPSS 20 software. Negligible change observed in visual acuity and contrast sensitivity with p value of 0.015 and 0.010 respectively. No change is observed in stereopsis. Ishihara shows normal color vision with x chrome lenses while D-15 test shows reduction in severity of color vision deficiency. Conclusions: If X chrome color contact lenses are implemented during child’s learning period, it will eliminate many of the academic challenges that are faced with color coded learning and teaching materials and improve their quality for many recreational activities.
关键词： Pediatrics,Color vision,X chrome contact lens
更新于2025-09-10 09:29:36
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Color vision testing versus pattern visual evoked potentials and optical coherence tomography parameters in subclinical optic nerve involvement in multiple sclerosis
摘要： Acute idiopathic demyelinating optic neuritis is frequently the initial manifestation of multiple sclerosis (MS). We aimed to discuss the value of color vision testing to detect possible optic nerve involvement in patients with MS who had no history of optic neuritis. We evaluated color vision with Farnsworth-Munsell 100 (FM-100) hue test. Total error scores (TES), partial error scores for the red-green axis (RGS) and blue-yellow axis (BYS) were calculated. Topographic optic disc parameters (RNFL, RA, DA, CV, RV, and vertical C/D ratio), total macular volume (TMV), central macular thickness (CMT), and retinal ganglion cell layer (RGCL) were determined using spectral domain optical coherence tomography (SD-OCT). Choroidal thickness (CT) was measured using enhanced depth imaging optical coherence tomography (EDI-OCT). Pattern visual evoked potentials (PVEP) were also performed. Twenty-eight patients with RRMS (56 eyes) and 25 healthy controls (50 eyes) were included. P100 latencies were significantly delayed and P100 amplitudes were significantly reduced in the patient group compared with the controls (p (cid:1) 0.05). Statistically significant thinning was found in temporal quadrant in the patient group compared with the controls (p = 0.002). TES RGS, and BYS were all increased in the patient group but this was not statistically significant. We found no correlation between TES, RGS, BYS, and P100 latencies or OCT parameters. In our investigation as to whether color vision testing could be a simple biomarker for showing neurodegeneration of the anterior visual pathway regardless of optic neuritis, PVEP and OCT-assessed RNFL thickness seemed to be a more valuable biomarker than color vision testing.
关键词： Visual evoked potentials,Optical coherence tomography,Color vision,Multiple sclerosis,Subclinical optic neuritis,Retinal nerve fiber layer
更新于2025-09-09 09:28:46
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Circuitry to explain how the relative number of L and M cones shapes color experience
摘要： The wavelength of light that appears unique yellow is surprisingly consistent across people even though the ratio of middle (M) to long (L) wavelength sensitive cones is strikingly variable. This observation has been explained by normalization to the mean spectral distribution of our shared environment. Our purpose was to reconcile the nearly perfect alignment of everyone’s unique yellow through a normalization process with the striking variability in unique green, which varies by as much as 60 nm between individuals. The spectral location of unique green was measured in a group of volunteers whose cone ratios were estimated with a technique that combined genetics and flicker photometric electroretinograms. In contrast to unique yellow, unique green was highly dependent upon relative cone numerosity. We hypothesized that the difference in neural architecture of the blue-yellow and red-green opponent systems in the presence of a normalization process creates the surprising dependence of unique green on cone ratio. We then compared the predictions of different theories of color vision processing that incorporate L and M cone ratio and a normalization process. The results of this analysis reveal that—contrary to prevailing notions–postretinal contributions may not be required to explain the phenomena of unique hues.
关键词： primate retina,color vision,L:M cone ratio,unique hues,neural circuitry
更新于2025-09-04 15:30:14