May 2015
Spotlight Summary by Shakil Rehman
LCD-based digital eyeglass for modulating spatial-angular information
Display technology is a ubiquitous part of our everyday life. We spend a considerable part of our waking time in front of a screen, such as working on a computer, watching TV, using mobile devices such as a tablets and phones, to name a few. Most of the viewing screens of such devices are based on liquid crystal display (LCD) technology.
However, LCDs have a wide range of applications other than the ones mentioned above. In particular, the authors of this Optics Express article have developed digital “adaptive eyeglasses”, with an LCD device for adaptively controlling the light transmission. The key application presented by the authors is the suppression of headlamp light glare of incoming vehicles at night-time driving. By incorporating a web camera and a pair of LCD displays embedded in 3D-printed eyeglasses, the authors assembled a device that can adaptively reduce the light transmission from bright sources.
The idea behind this technology is borrowed from programmable aperture imaging techniques in which spatial and angular transmission of light is controlled with LCD devices. A small camera is used to capture the images of the scene in front of the eyeglass wearer. The camera is inserted in the middle of the two LCD devices that are acting as the viewing ports of the eyeglasses so that the wearer can see through the pair of LCDs. The images from the camera are used to determine the angular location of the bright sources. This information is then used to change the transmission of the LCDs in a certain way so as to block the areas in the visual field that are bright. With the current design of the “adaptive eyeglasses”, the authors were able to demonstrate an 80% light reduction from bright sources, while at the same time keeping the other parts of the LCD pair transparent.
The LCDs used in the “adaptive eyeglasses” have low transmission (~30%) and extinction ratio (~80%) that limits the quality of visual field. The performance of this device ultimately depends on the refresh rate (currently 10fps), which is limited by the electronic processing, image acquisition and pattern displaying on the LCD.
Other than the adaptive control of blocking the headlamp glare of vehicles at night time driving, the authors see application of such “adaptive eyeglasses” in wearable technologies such Google glasses, and in spatially adjusting the contrast in the visual field for visually impaired.
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However, LCDs have a wide range of applications other than the ones mentioned above. In particular, the authors of this Optics Express article have developed digital “adaptive eyeglasses”, with an LCD device for adaptively controlling the light transmission. The key application presented by the authors is the suppression of headlamp light glare of incoming vehicles at night-time driving. By incorporating a web camera and a pair of LCD displays embedded in 3D-printed eyeglasses, the authors assembled a device that can adaptively reduce the light transmission from bright sources.
The idea behind this technology is borrowed from programmable aperture imaging techniques in which spatial and angular transmission of light is controlled with LCD devices. A small camera is used to capture the images of the scene in front of the eyeglass wearer. The camera is inserted in the middle of the two LCD devices that are acting as the viewing ports of the eyeglasses so that the wearer can see through the pair of LCDs. The images from the camera are used to determine the angular location of the bright sources. This information is then used to change the transmission of the LCDs in a certain way so as to block the areas in the visual field that are bright. With the current design of the “adaptive eyeglasses”, the authors were able to demonstrate an 80% light reduction from bright sources, while at the same time keeping the other parts of the LCD pair transparent.
The LCDs used in the “adaptive eyeglasses” have low transmission (~30%) and extinction ratio (~80%) that limits the quality of visual field. The performance of this device ultimately depends on the refresh rate (currently 10fps), which is limited by the electronic processing, image acquisition and pattern displaying on the LCD.
Other than the adaptive control of blocking the headlamp glare of vehicles at night time driving, the authors see application of such “adaptive eyeglasses” in wearable technologies such Google glasses, and in spatially adjusting the contrast in the visual field for visually impaired.
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Article Information
LCD-based digital eyeglass for modulating spatial-angular information
Zichao Bian, Jun Liao, Kaikai Guo, Xin Heng, and Guoan Zheng
Opt. Express 23(9) 11813-11818 (2015) View: Abstract | HTML | PDF