We demonstrate the validity of wavelet-based processing for recognition and classification of three-dimensional phase objects. One Fresnel digital hologram of each of the three-dimensional (3-D) phase objects to be cl...
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We demonstrate the validity of wavelet-based processing for recognition and classification of three-dimensional phase objects. One Fresnel digital hologram of each of the three-dimensional (3-D) phase objects to be classified is recorded. The electronic holograms are processed digitally to permit 3-D object information to be retrieved as two-dimensional digital complex images. We use a Mexican-hat wavelet-matched filter (WMF) to enhance the correlation peak and discriminate between the objects. The WMF performs a wavelet transform (WT) to enhance the significant features of the images and the correlation of the WT coefficients thus obtained. We compare the feasibility of a WMF-based object classifier with the matched-filter-based classifier to classify our four 3-D phase objects in a 3-D scene into TRUE or FALSE classes with minimal error. (c) 2006 Optical Society of America.
We report an imaging sensor capable of recording the optical properties of partially polarized light by monolithically integrating aluminum nanowire optical filters with a CCD imaging array. The imaging sensor, compos...
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We report an imaging sensor capable of recording the optical properties of partially polarized light by monolithically integrating aluminum nanowire optical filters with a CCD imaging array. The imaging sensor, composed of 1000 by 1000 imaging elements with 7.4 mu m pixel pitch, is covered with an array of pixel-pitch matched nanowire optical filters with four different orientations offset by 45 degrees. The polarization imaging sensor has a signal-to-noise ratio of 45dB and captures intensity, angle and degree of linear polarization in the visible spectrum at 40 frames per second with 300mW of power consumption. (c) 2010 Optical Society of America
A new method for deconvolution of one-dimensional and multidimensional data is suggested. The proposed algorithm is local in the sense that the deconvolved data at a given point depend only on the value of the experim...
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A new method for deconvolution of one-dimensional and multidimensional data is suggested. The proposed algorithm is local in the sense that the deconvolved data at a given point depend only on the value of the experimental data and their derivatives at the same point. In a regularized version of the algorithm the deconvolution is constructed iteratively with the help of an approximate deconvolution operator that requires only the low-order derivatives of the data and low-order integral moments of the point-spread function. This algorithm is expected to be particularly useful in applications in which only partial knowledge of the point-spread function is available. We tested and compared the proposed method with some of the popular deconvolution algorithms using simulated data with various levels of noise. (C) 2003 Optical Society of America.
The quality-control process of polarizer production is hampered by the presence of extremely-slight transparent aesthetic defects (ESTADs). The saturated imaging method based on stripe structured backlight can effecti...
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The quality-control process of polarizer production is hampered by the presence of extremely-slight transparent aesthetic defects (ESTADs). The saturated imaging method based on stripe structured backlight can effectively improve the imaging contrast of ESTADs. However, the contrast is very sensitive to the saturation degree, which requires careful manual selection. This paper presents a saturation level-guided image enhancement method that is simple to deploy in industrial settings. First, a new definition of the saturation level for structured backlit imaging with translation, scale, and rotation invariance is proposed. Then, an empirical model of contrast versus saturation level is established. Using the contrast data measured at five saturation levels, the optimal saturation level can be estimated using the parameter optimization method. The experimental results demonstrate that the method is effective, easy to use, and an improvement of imaging effects for transparent thin-film defect detection algorithms. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Eye tracking is one of the latest technologies that has shown potential in several areas, including biometrics;human-computer interactions for people with and without disabilities;and noninvasive monitoring, detection...
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Eye tracking is one of the latest technologies that has shown potential in several areas, including biometrics;human-computer interactions for people with and without disabilities;and noninvasive monitoring, detection, and even diagnosis of physiological and neurological problems in individuals. Current noninvasive eye-tracking methods achieve a 30-Hz rate with a low accuracy in gaze estimation, which is insufficient for many applications. We propose a new noninvasive optical eye-tracking system that is capable of operating at speeds as high as 6-12 kHz. A new CCD video camera and hardware architecture are used, and a novel fast algorithm leverages specific features of the input CCD camera to yield a real-time eye-tracking system. A field-programmable gate array is used to control the CCD camera and to execute the operations. Initial results show the excellent performance of our system under severe head-motion and low-contrast conditions. (C) 2005 Optical Society of America.
In an RGB-LED-based optical camera communication (OCC) system, the inter-symbol interference and inter-channel interference deteriorate the transmission performance considerably. In this paper, a two-dimensional CNN s...
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In an RGB-LED-based optical camera communication (OCC) system, the inter-symbol interference and inter-channel interference deteriorate the transmission performance considerably. In this paper, a two-dimensional CNN structure is proposed for data recovery by learning features between color channels and neighboring symbols in the rolling shutter based OCC system under random data transmission. Moreover, we further propose an XOR-based data loss compensation method to realize 21% data rate improvement by restoring the lost data during the transmission. A record-high data rate at 47 kbit/s has been experimentally achieved for an RGB-LED-based OCC system using a rolling shutter camera in a smartphone. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
To deal with the requirement of high-precision localization of large-size workpieces in an industrial environment, an improved shape-based matching algorithm is proposed based on the phase stretching transformation an...
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To deal with the requirement of high-precision localization of large-size workpieces in an industrial environment, an improved shape-based matching algorithm is proposed based on the phase stretching transformation and the iterative closest point algorithms. Basler industrial cameras are used to collect images of large-size workpieces, such as glass. The experimental results show that the average localization error is 0.05 +/- 0.013 mm, which can meet the requirements of practical applications. This algorithm can effectively and accurately achieve high-precision localization of different positions of multi-directionally transformed objects in industrial environments. (C) 2021 Optical Society of America
An optical imaging system often has problems of high complexity and low energy transmittance to compensate for aberrations. Here we propose a method to correct aberrations by coupling an optical subsystem with a digit...
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An optical imaging system often has problems of high complexity and low energy transmittance to compensate for aberrations. Here we propose a method to correct aberrations by coupling an optical subsystem with a digital subsystem. Specifically, in the global optimization process, the two subsystems correct their respective, easily handled aberrations so that the final imaging aberration is minimized. We design simple lenses with this method and assess imaging quality. In addition, we conduct a tolerance analysis for the proposed method and verify the effectiveness of deconvolution using a spatially varying point spread function (SVPSF) in the actual imaging process. Simulation results show the superiority of the proposed method compared with the conventional design and the feasibility of simplifying the optical system. Experimental results prove the effectiveness of deconvolution using SVPSF. (C) 2022 Optica Publishing Group
We propose an integrated holographic waveguide display system. An infrared volume holographic grating (IVHG) and a visible light grating are recorded on the mine waveguide to achieve the purpose of a common light path...
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We propose an integrated holographic waveguide display system. An infrared volume holographic grating (IVHG) and a visible light grating are recorded on the mine waveguide to achieve the purpose of a common light path for system miniaturization. Simulated and experimental results verify the feasibility of this method. The coupling efficiencies of the infrared module for eye tracking and the visible light module for augmented reality (AR) display are 40% and 45%. The holographic waveguide has a weight of only 4.3 grams. It is believed that this technique is a good way to achieve a light and thin eye tracking near-eye display. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Using the image-based optical measurement method known as axially distributed sensing ( ADS), the depth information of a scene is retrieved by evaluating images recorded with a camera positioned on multiple points alo...
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Using the image-based optical measurement method known as axially distributed sensing ( ADS), the depth information of a scene is retrieved by evaluating images recorded with a camera positioned on multiple points along a common optical axis. We describe the design of a monoscopic lens that images the scene from two different on-axis points of perspective simultaneously onto a single camera. Designed for use in a territorial surveillance video system, this lens allows for capturing 3D scene information based on ADS with a single shot. We present the physical foundations of this approach and its implementation as a compact lens system and show the usability of the system prototype, supported by performance tests. (C) 2014 Optical Society of America
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