Light Attenuation / Multi-spectral Displays

2024

1. IEEE TVCG

   

   J6 StainedSweeper: Compact, Variable-Intensity Light-Attenuation Display with Sweeping Tunable Retarders

   Yuichi Hiroi, Takefumi Hiraki, and Yuta Itoh

   IEEE Transactions on Visualization and Computer Graphics, May 2024

   Abs Bib DOI PDF Supp Video

   Light Attenuation Displays (LADs) are a type of Optical See-Through Head-Mounted Display (OST-HMD) that present images by attenuating incoming light with a pixel-wise polarizing color filter. Although LADs can display images in bright environments, there is a trade-off between the number of Spatial Light Modulators (SLMs) and the color gamut and contrast that can be expressed, making it difficult to achieve both high-fidelity image display and a small form factor. To address this problem, we propose StainedSweeper, a LAD that achieves both the wide color gamut and the variable intensity with a single SLM. Our system synchronously controls a pixel-wise Digital Micromirror Device (DMD) and a nonpixel polarizing color filter to pass light when each pixel is the desired color. By sweeping this control at high speed, the human eye perceives images in a time-multiplexed, integrated manner. To achieve this, we develop the OST-HMD design using a reflective Solc filter as a polarized color filter and a color reproduction algorithm based on the optimization of the time-multiplexing matrix for the selected primary color filters. Our proof-of-concept prototype showed that our single SLM design can produce subtractive images with variable contrast and a wider color gamut than conventional LADs.

   @article{hiroi2024stainedsweeper,
     author = {Hiroi, Yuichi and Hiraki, Takefumi and Itoh, Yuta},
     journal = {IEEE Transactions on Visualization and Computer Graphics},
     title = {StainedSweeper: Compact, Variable-Intensity Light-Attenuation Display with Sweeping Tunable Retarders},
     year = {2024},
     volume = {30},
     number = {5},
     pages = {2682-2692},
     keywords = {Image color analysis;Optical filters;Filtering algorithms;Light sources;Optical imaging;Optical reflection;Optical polarization;Light attenuation display;see-through display;augmented reality;time-multiplexing;polarized color filter},
     doi = {10.1109/TVCG.2024.3372058},
     issn = {1941-0506},
     month = may,
   }

2. IEEE ISMAR

   CF9 FactoredSweeper: Optical See-Through Display Integrating Light Attenuation and Addition with a Single Spatial Light Modulator

   Yuichi Hiroi, Takefumi Hiraki, and Yuta Itoh

   In 2024 IEEE International Symposium on Mixed and Augmented Reality (ISMAR), Oct 2024

   Abs Bib DOI PDF Supp Video

   Light Attenuation Displays (LADs), a subset of Optical See-Through Head-Mounted Displays (OST-HMDs), enable image display in bright environments by filtering incident light at the pixel level. Although recent methods have proposed single-DMD light attenuation, they do not consider additive color display and background compensation, limiting their applicability in real-world scenarios. We present FactoredSweeper, a single digital micromirror device (DMD) system that incorporates both light attenuation and addition. By synchronizing the DMD, color filter, and light source, our system generates an additive virtual image, light attenuation, and occlusion through time multiplexing. To produce the target image while compensating for the background, we optimize time-multiplexed binary DMD patterns and LED/color filter schedules using perceptually-driven non-negative matrix factorization. Simulations and prototypes demonstrate that our integrated attenuation-addition single-SLM system achieves superior dynamic range and perceptual image quality compared to conventional occlusion-capable OST-HMDs using grayscale occlusion masks.

   @inproceedings{hiroi2024factored,
     author = {Hiroi, Yuichi and Hiraki, Takefumi and Itoh, Yuta},
     title = {FactoredSweeper: Optical See-Through Display Integrating Light
     Attenuation and Addition with a Single Spatial Light Modulator},
     booktitle = {2024 IEEE International Symposium on Mixed and Augmented Reality (ISMAR)},
     year = {2024},
     volume = {},
     number = {},
     pages = {61--70},
     keywords = {Light attenuation display; see-through display; augmented reality, time-multiplexing; perceptual-driven matrix factorization},
     month = oct,
     doi = {10.1109/ISMAR62088.2024.00020},
   }

2020

1. IEEE TVCG

   

   J2 StainedView: Variable-Intensity Light-Attenuation Display with Cascaded Spatial Color Filtering for Improved Color Fidelity

   Takumi Kaminokado, Yuichi Hiroi, and Yuta Itoh

   IEEE Transactions on Visualization and Computer Graphics, Dec 2020

   Abs Bib DOI PDF

   We present StainedView, an optical see-through display that spatially filters the spectral distribution of light to form an image with improved color fidelity. Existing light-attenuation displays have limited color fidelity and contrast, resulting in a degraded appearance of virtual images. To use these displays to present virtual images that are more consistent with the real world, we require three things: intensity modulation of incoming light, spatial color filtering with narrower bandwidth, and appropriate light modulation for incoming light with an arbitrary spectral distribution. In StainedView, we address the three requirements by cascading two phase-only spatial light modulators (PSLMs), a digital micromirror device, and polarization optics to control both light intensity and spectrum distribution. We show that our design has a 1.8 times wider color gamut fidelity (75.8% fulfillment of sRGB color space) compared to the existing single-PSLM approach (41.4%) under a reference white light. We demonstrated the design with a proof-of-concept display system. We further introduce our optics design and pixel-selection algorithm for the given light input, evaluate the spatial color filter, and discuss the limitation of the current prototype.

   @article{kamino2020stainedview,
     author = {Kaminokado, Takumi and Hiroi, Yuichi and Itoh, Yuta},
     journal = {IEEE Transactions on Visualization and Computer Graphics},
     title = {StainedView: Variable-Intensity Light-Attenuation Display with Cascaded Spatial Color Filtering for Improved Color Fidelity},
     year = {2020},
     volume = {26},
     number = {12},
     pages = {3576-3586},
     keywords = {Image color analysis;Optical imaging;Optical polarization;Adaptive optics;Optical distortion;Optical modulation;Nonlinear optics;Light attenuation display;phase modulation;see-through display;vision augmentation;augmented reality},
     doi = {10.1109/TVCG.2020.3023569},
     issn = {1941-0506},
     month = dec,
   }