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Industrial and engineering aspects of LC applications
Published in L. Vicari, Optical Applications of Liquid Crystals, 2016
For projector application, a high extinction ratio (contrast ratio) of more than 500 of amplitude modulation is required. Figure 6.15 depicts the optical system widely used in LC projectors. There are three amplitude modulation SLMs surrounding a dichroic prism [18].
Color image processing for digital cameras
Published in Sharma Gaurav, Digital Color Imaging Handbook, 2017
Multi-sensor color. This method uses a beam splitter, which is typically a dichroic prism, to separate the light into red, green, and blue components. These are focused onto three separate monochrome image sensors. 9
Seamless holographic image generation for a multi-vision system
Published in Journal of Information Display, 2022
Woonchan Moon, Hosung Jeon, Sungjae Park, Soobin Kim, Hwi Kim, Joonku Hahn
This system employs a 5-inch transmission-type commercial LCD with full color FHD resolution and opaque bezels including the gate driving circuit and metal electrodes (Figure 1[a]). These bezels create rectangular seam lines inside the multi-vision configuration (Figure 1[b]), thus leading to discontinuous images and lower image quality of the resulting multi-vision display. It is difficult to completely remove the seam in the display image of a multi-vision system. The experimental setup is presented in Figure 1(c). We use an RGB light-emitting diode (LED) system to illuminate the multi-vision system. The system parameters are shown in Table 1. The central wavelengths of the RGB LED system are 640, 525, and 450 nm, respectively. The multi-vision system consists of eight SLMs, has a diagonal size of 13.13 in., and has a total of approximately 16M pixels. The size of the viewing window generated by this system is 2828. Figures 1(d), (e), and (f) present the 42 LCD multi-vision section, the RGB LED light sources, and the optical components of the system (i.e. the parabolic mirror and beam splitter). The parabolic mirror used as a field lens has a focal length of 1.8 m, and the viewing distance in the multi-vision system is 3.6 m, which is twice the focal length [13]. A dichroic prism is used to combine the RGB beams.
The application of indocyanine green (ICG) and near-infrared (NIR) fluorescence imaging for assessment of the lymphatic system in reconstructive lymphaticovenular anastomosis surgery
Published in Expert Review of Medical Devices, 2021
Albert H. Chao, Steven A. Schulz, Stephen P. Povoski
Only certain manufacturers of operative microscopes offer models with the functionality of integrated NIR illumination. Due to the high cost of operative microscopes, it can be impractical for many centers to purchase a new operative microscope just for its integration capability. Seki et al. described the use of a visualization system that is separate from the operative microscope (Lightvision; Shimazu Corporation, Kyoto, Japan) that confers the ability to continuously view the surgical field with NIR illumination in real-time while operating[47]. This video camera device is equipped with a dichroic prism that can separate the NIR fluorescence light of ICG from visible light of the operating microscope, and thus does not require turning off overhead lights which typically interfere with NIR illumination. One important feature of this device is that the video screen simultaneously displays three views: (1) NIR illumination, (2) visible light illumination, and (3) a superimposed view of both NIR and visible light illumination. This is important because this device, unlike integrated operative microscopes, does not provide magnification and thus the superimposed view aids microsurgeons in orienting to the surgical field in the absence of magnification. While microsurgeons use the operative microscope to perform the operation, they may intermittently view this separate video screen to guide the dissection. The authors describe the use of this device in 10 patients with upper extremity lymphedema. They report being able to visualize 86.7% of subcutaneous lymphatic vessels. The 13.3% of subcutaneous lymphatic vessels that they were not able to visualize were specifically in patients with some degree of dermal backflow of dye in which the subcutaneous lymphatic vessels were obscured. In addition, they were able to visualize ICG flow across anastomoses 76.7% of the time. In the 23.3% of anastomoses where this was not possible, it was again in the setting of dermal backflow in the background.