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Digital Image Processing Systems
Published in Scott E. Umbaugh, Digital Image Processing and Analysis, 2017
The current standards for HDTV use several different formats. These include a resolution of 1280 columns by 720 rows (lines), in a progressive scan mode, referred to as 720p, 1920 columns by 1080 rows for 1080p, or 1920 × 1080 in an interlaced mode, called 1080i. While the SDTV uses a 4:3 aspect ratio, the HDTV standards specifies a 16:9 aspect ratio. The aspect ratio is the width-to-height ratio of the display device, shown in Figure 2.1-4. The aspect ratio of 35-mm film cameras is 3:2, and standard digital cameras typically use 3:2 or 4:3.
Display for Medical Imaging and DICOM Grayscale Standard Display Function Fundamentals
Published in Paolo Russo, Handbook of X-ray Imaging, 2017
The display device, frequently called the monitor or screen, is an optoelectronic device such as a liquid crystal display (LCD) or cathode ray tube (CRT) monitor (Badano et al. 2004) that converts digital information into optical signals. The display device is driven by the driving computer via the display interface, such as the Digital Visual Interface (DVI) or the DisplayPort.
Synthesis of cholesterol containing unsymmetrical dimers: a new series of liquid crystals
Published in Liquid Crystals, 2022
Tiago E. A. Frizon, André A. Vieira, Fernando C. Giacomelli, Rodrigo Cercená, Alexandre Dal Bó, Eduardo Zapp, Eduardo Junca, Antônio A. Chepluki, Cassiano D. Tomasi, Luiz B. Ribeiro, Sumbal Saba, Jamal Rafique
Unsymmetric cholesterol-based LC dimers have some peculiar advantages. For example, chiral cholesteryl moiety entitles many unique optical properties such as selective reflection, circular dichroism, and thermo-optical effects besides the properties of conventional rigid aromatic LC dimers. In this aspect, they could be applied in optical storage, optical switching, nonlinear optics, and liquid crystal display device [12]. Although there are various unsymmetric cholesterol-based LC dimers available in the literature, the procedure to obtain these materials uses non-accessible and expensive reagents, and presents a complex synthetic route with multiple steps [13]. Because of this, the development of new LC dimers via a simple and efficient synthetic approach to access is highly desirable.
Diffraction phase microscopy using a defocus grating
Published in Journal of Modern Optics, 2022
Zhi Zhong, Chen Wang, Lei Liu, Lei Yu, Mingguang Shan
Obviously, both the central distance s and the carrier frequency f0 are straightly proportional to the displacement Δf. In this case, even though the other optical parameters, such as that of the wavelength, the grating period and the lens focal length, are determined, s and f0 can be flexibly and linearly modulated by Δf. In this case, the DHF alignment can be adjusted by slightly shifting the grating along the optical axis and/or DHF along the Fourier plane without considering the strict matching relationship among different optical parameters in previous DPM even other optical parameters are fixed. As a result, a high-precision 3D stage or complex liquid crystal display device [19–21] is then no longer required. While to satisfy the varying requirement of different samples [11], various MOs should be switched to operate at optimal resolution, but the carrier frequency in the proposal can be also modulated by shifting the grating mainly to avoid aliasing in the Fourier plane even other optical parameters are fixed.
Theoretical analysis on power stability and switch time of the non-mechanical beam steering using liquid crystal optical phased array
Published in Liquid Crystals, 2018
Xiangru Wang, Liang Wu, Xiaoxian He, Xinning Huang, Qinggui Tan
In comparison with ordinary liquid crystal display device, the core point of concern is the depth of phase modulation. Phase modulation on each unit is a relative value. So, in general, to improve the steering speed, a method of overdrive is usually suggested to load a bias voltage where the relative phase modulation is , and the corresponding refractive index of e-beam is , , as show in Figure 6. On the condition of overdriving, loading voltage is usually much larger than the threshold , to simplify the equation of switch time, if we consider that the minimum load voltage , Equation (12) is rewritten as