Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"modulation transfer function (MTF)"”.
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The direct measurement of system Modulation Transfer Function (MTF) for an AN/AVS-6 Aviator's Night Vision Imaging System (ANVIS)
… response of these systems has been ignored. Modulation Transfer Function (MTF) performance specifications have been extensively researched for the components of night vision imaging systems such as the lenses and the image intensifier tube. The current method for calculating the system MTF is …
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Accurate characterization of nanophotonic grating structures
… measuring the resolution of the device using a Modulation Transfer Function, MTF, technique. MTF is commonly measured using either the line pair method or the slant edge method. This thesis proposes a new method to measure MTF using single pixel illumination and point spread function. Results …
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Design and optimization of imaging systems by engineering the pupil function
… a particular purpose is to engineer the pupil function of the imaging system. This includes designing a pupil surface and often involves the simultaneous design of a post-processing algorithm. Currently these design processes are performed mostly by using numerical optimization methods. …
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Application of a High‑Resolution Computed Radiography System in Detecting an Iodinated X‑ray Contrast Agent: Small Animal Phantom Study
… of CR image quality by measuring presampled Modulation Transfer Function (MTF), Noise Power Spectrum (NPS), Relative Standard Deviation of Noise (RSD), Noise Equivalent Quanta (NEQ), and Detective Quantum Efficiency (DQE).</p> <p>Next, dual‑energy and temporal subtraction techniques were …
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A study of CMOS technologies for image sensor applications
… achievable optical lens resolution. Using the modulation transfer function (MTF) as an index, optical simulations are performed to examine the relation between the lens resolution and the lens complexity.
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Quantification of the Depth-of-Field in a Self-Aligned Focusing Schlieren System
… using a Fourier optics framework based on the modulation transfer function (MTF) and point spread function (PSF). Depth-dependent MTF measurements from a slanted-edge target and PSF measurements from a 100 µm pinhole target show that the depth response of the SAFS system changes gradually with …
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Theoretical and Experimental Evaluation of Spatial Resolution in a Variable Resolution X-Ray Computed Tomography Scanner
… described by the detector presampling modulation transfer function (MTF), and the post-reconstruction spatial resolution, given by the scanner reconstruction MTF. The detector presampling MTF was modeled by the Monte Carlo simulation and measured by the moving-slit method. The modeled …
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Quantitative Automated Object Wave Restoration in High-Resolution Electron Microscopy
… relied on the unjustified assumption that the Modulation Transfer Function (MTF) also correctly describes the spatial frequency dependent attenuation of the electron shot noise. A new theory is therefore presented that distinguishes between signal and noise transfer. This facilitates the …
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Characterizing the perceived quality degradation of still-camera motion blur
… (blur size, Subjective Quality Factor, SQF; Modulation Transfer Function ,Area, MTFA; and Equivalent Passband, Ne), derived analytically from the motion data, were used as dependent measures for statistical analysis. All three modulation-transfer-function (MTF)-based analytic quality metrics …
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Scene-Dependency of Spatial Image Quality Metrics
… critical to overall perceived image quality. The Modulation Transfer Function (MTF) and Noise Power Spectrum (NPS) describe the signal (contrast) transfer and noise characteristics of a system, respectively, with respect to spatial frequency. They are both, strictly speaking, only applicable to …
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Deep structure ultrasound imaging using fundamental and third harmonic coded excitation techniques
… max (FWHM) criteria of the echo envelope and the modulation transfer function (MTF) were used. With Golay coding and 1, 3 REC, the axial resolutions of the fundamental and third harmonic components were calculated to be 0.91 mm and 0.7 mm, respectively. These values for axial resolution were 0.6 …
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An analytic model to predict detection threshold and performance data for misconvergence on a shadow-mask CRT
… color CRT display system. The model incorporates functions to describe the unique features of a color CRT, that is, the discrete sampling imposed by the shadow mask/ phosphor-dot arrangement as well as the electron beam phase relationships. The model also includes a flexible beam profile which …
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Camera Spatial Frequency Response Derived from Pictorial Natural Scenes
… research conducted in this thesis focuses on the Modulation Transfer Function (MTF), a widely used camera performance measurement employed to describe resolution and sharpness. Traditionally measured under controlled conditions with characterised test charts, the MTF is a measurement restricted to …
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Liquid crystal photonic devices based on conductive polymers = Dispositivos fotónicos de cristal líquido basados en polímeros conductores
… Such analysis consists in the calculus of the Modulation Transfer Function (MTF) as function of the spatial resolution at different voltages (at different focal lengths). MTF variation as function of aperture radius of the lens leads us information about the contrast (at a spatial resolution of …
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Assessment and optimisation of digital radiography systems for clinical use
… digital storage and high bandwidth data transfer networks have lead to an enormous increase in the number of digital radiography systems in the UK. There are a number of competing digital radiography (DR) technologies, the most common are computer radiography (CR) systems followed by …
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Imaging Techniques for Proton Range Determination in Proton Therapy
… respectively. The frequency at 10% of the modulation transfer function (MTF) was 6.38 cm-1. The mean signal-to-noise ratio (SNR) of all the inserts was 2.45. The mean imaging dose was 0.29 cGy and 0.25 cGy at the head and lung region of the adult phantom, respectively. The results suggest …
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Theoretical and experimental assessment of the optical response of planar microlens arrays
The purpose of this thesis is to develop a theoretical method to estimate the optical properties and response of a homogenous, apposition microlens array. While other similar studies of microlens arrays have been performed, none were found to determine the total field of view, overlap in the field …