In embedded systems, many numerical algorithms are implemented with fixed-point arithmetic to meet area cost and power constraints. Fixed-point encoding decisions can significantly affect cost and performance. To eval...
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ISBN:
(纸本)9781479962785
In embedded systems, many numerical algorithms are implemented with fixed-point arithmetic to meet area cost and power constraints. Fixed-point encoding decisions can significantly affect cost and performance. To evaluate their impact on accuracy, designers resort to simulations. Their high running-time prevents thorough exploration of the design-space. To address this issue, analytical modeling techniques have been proposed, but their applicability is limited by scalability issues. In this paper, we extend these techniques to a larger class of programs. We use polyhedral methods to extract a more compact, graph-based representation of the program. We validate our approach with a several image and signal processingalgorithms.
We present an algorithm for generating a surface approximation of microcrystalline silicon (mu c-Si) layers after plasma enhanced chemical vapor deposition (PECVD) onto surface textured substrates, where data of the t...
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We present an algorithm for generating a surface approximation of microcrystalline silicon (mu c-Si) layers after plasma enhanced chemical vapor deposition (PECVD) onto surface textured substrates, where data of the textured substrate surface are available as input. We utilize mathematical imageprocessing tools and combine them with an ellipsoid generator approach. The presented algorithm has been tuned for use in thin-film silicon solar cell applications, where textured surfaces are used to improve light trapping. We demonstrate the feasibility of this method by means of optical simulations of generated surface textures, comparing them to simulations of measured atomic force microscopy (AFM) scan data of both Aluminum-doped zinc oxide (AZO, a transparent and conductive material) and mu c-Si layers. (C) 2013 Optical Society of America
The accuracy test of a corneal topographer based on null-screen method is presented. This accuracy test is conducted by testing a calibration sphere. The accuracy found was of 5.8 μm for differences of elevation;75 ...
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Behavior analysis of construction safety systems is of fundamental importance to avoid accidental injuries. Traditionally, measurements of dynamic actions in civil engineering have been done through accelerometers, bu...
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Behavior analysis of construction safety systems is of fundamental importance to avoid accidental injuries. Traditionally, measurements of dynamic actions in civil engineering have been done through accelerometers, but high-speed cameras and imageprocessing techniques can play an important role in this area. Here, we propose using morphological image filtering and Hough transform on high-speed video sequence as tools for dynamic measurements on that field. The presented method is applied to obtain the trajectory and acceleration of a cylindrical ballast falling from a building and trapped by a thread net. Results show that safety recommendations given in construction codes can be potentially dangerous for workers. (C) 2013 Optical Society of America
Given the importance of digital imageprocessing and the significance of their implementations on hardware to achieve better performance, this paper reviews the advantages of using FPGA over softwares and DSPs as a pl...
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ISBN:
(纸本)9781479923724
Given the importance of digital imageprocessing and the significance of their implementations on hardware to achieve better performance, this paper reviews the advantages of using FPGA over softwares and DSPs as a platform for implementation of digital imageprocessing applications. This work presents a hardware implementation of a FPGA-based real-time configurable system consisting of imageprocessing low-level operators such as, contrast adjustment, brightness adjustment, inverting an image and pseudo-color operation. The paper presents a Verilog description of a real-time configurable system for digital imageprocessing and focuses on medical images enhancement using this system. The solution provides an innovative hardware implementation and simulation, followed by immediate synthesis on FPGA.
Diabetes is a familiar disease in modern society. In the early stage of diabetes, symptoms are unobvious, but they usually induce diabetic autonomic neuropathy or, worse, cardiovascular autonomic neuropathy. Pupillome...
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Diabetes is a familiar disease in modern society. In the early stage of diabetes, symptoms are unobvious, but they usually induce diabetic autonomic neuropathy or, worse, cardiovascular autonomic neuropathy. Pupillometers are effective instruments for observing human pupils. This article presents a novel wearable pupillometer design, without external light artifacts, and an embedded algorithm with blinking elimination, which investigates autonomic neuropathy through recording pupil dynamics triggered by an external sensitive invisible light source. The pupillometer is experimented on 36 healthy subjects and 10 diabetic patients under four different colors (white, red, green, and blue) as well as two different light intensities: 50 and 500 mcd. Ten parameters derived from pupil diameter, pupil response time, and pupil response speed will be evaluated for the healthy subjects and diabetic patients. The results show that three in four parameters related to pupil diameters, one in four related to light intensities, and one in two related to pupil response speed could have significant differences (p < 0.05) between healthy subjects and diabetic patients. These parameters obtain over 85% sensitivity, 83% specificity, and 88% accuracy. The pupillometer is proven reliable, effective, portable, and inexpensive for diagnosing diabetes in an early stage. (C) 2014 Optical Society of America
This paper deals with the fast-developing area of computational photography where a combination of imaging techniques and efficient image processing algorithms is done to generate a super imaging system. In recent yea...
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This paper deals with the fast-developing area of computational photography where a combination of imaging techniques and efficient image processing algorithms is done to generate a super imaging system. In recent years, three main implementations of the computational photography philosophy were intensively investigated and demonstrated: (i) multiple aperture, (ii) light field photography, and (iii) multiexposure. The paper provides a mini-review of these three approaches and shows ways to improve and combine them toward a super imaging system. As a conclusion, the paper provides preliminary guidelines for fusing the three approaches into one integrated super imaging system with optimized performance. (C) 2013 Optical Society of America
This paper presents an algorithm for reducing speckle noise from optical coherence tomography (OCT) images using an artificial neural network (ANN) algorithm. The noise is modeled using Rayleigh distribution with a no...
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This paper presents an algorithm for reducing speckle noise from optical coherence tomography (OCT) images using an artificial neural network (ANN) algorithm. The noise is modeled using Rayleigh distribution with a noise parameter, sigma, estimated by the ANN. The input to the ANN is a set of intensity and wavelet features computed from the image to be processed, and the output is an estimated sigma value. This is then used along with a numerical method to solve the inverse Rayleigh function to reduce the noise in the image. The algorithm is tested successfully on OCT images of Drosophila larvae. It is demonstrated that the signal-to-noise ratio and the contrast-to-noise ratio of the processed images are increased by the application of the ANN algorithm in comparison with the respective values of the original images. (C) 2013 Optical Society of America
This paper proposes an approach based on an optical imaging technique for the period measurement of fiber Bragg gratings (FBG). The simple, direct technique involves a differential interface contrast (DIC) microscope ...
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This paper proposes an approach based on an optical imaging technique for the period measurement of fiber Bragg gratings (FBG). The simple, direct technique involves a differential interface contrast (DIC) microscope and a high-resolution CCD camera. imageprocessing is performed on the microscope images to obtain low-noise grating profiles and then the grating periods. Adopting a large image sample size in the imageprocessing can reduce uncertainty. During the investigation, FBGs of different grating periods are fabricated by prestraining the photosensitive fibers during the UV-writing process. A good linearity between the measured Bragg wavelengths and grating periods is observed and the measured strain-optics coefficient was found to be in agreement with reported literature. (C) 2013 Optical Society of America
We propose a single-step method appropriated for a fiber-optic probe-based full-range spectral domain optical coherence tomography (OCT). The fiber-optic probe was scanned over a sample with a magnetically driven actu...
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We propose a single-step method appropriated for a fiber-optic probe-based full-range spectral domain optical coherence tomography (OCT). The fiber-optic probe was scanned over a sample with a magnetically driven actuator. In the reference arm, a phase shift of pi/2 was applied during two neighbor axial scanning, from which the complex spectral interferogram was directly reconstructed. Since the complex-conjugate-free OCT image is obtained by doing just one Fourier transform on the complex interferogram, obtaining the full-range image is simple in algorithm and effective in computation time. Some full-range images of biological samples created with the proposed method are presented and the processing time is analyzed. (C) 2013 Optical Society of America
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