Isotropic image edge enhancement with high contrast can be achieved using a spiral phase filter (SPF) in a 4f optical system. However, real-time application of edge enhancement with SPF has generally been limited due ...
详细信息
Isotropic image edge enhancement with high contrast can be achieved using a spiral phase filter (SPF) in a 4f optical system. However, real-time application of edge enhancement with SPF has generally been limited due to the requirement of coherent light or complex phase-shifting operation. In this paper, we demonstrate a real-time image edge enhancement method using a SPF and a graphic processing unit (GPU). By implementing the process of virtual spiral phase filtering on GPU, we are able to speed up the whole procedure by more than 8.3x with respect to CPU processing, and ultimately achieve video rate for megapixel images. In particular, our implementation can achieve higher speedup for more multiple images. These developments are increasing the potential for image edge enhancement of moving objects. (C) 2014 Optical Society of America
In this paper, the night sky star imageprocessing algorithm, consisting of image preprocessing, star pattern recognition, and centroiding steps, is improved. It is shown that the proposed noise reduction approach can...
详细信息
In this paper, the night sky star imageprocessing algorithm, consisting of image preprocessing, star pattern recognition, and centroiding steps, is improved. It is shown that the proposed noise reduction approach can preserve more necessary information than other frequently used approaches. It is also shown that the proposed thresholding method unlike commonly used techniques can properly perform image binarization, especially in images with uneven illumination. Moreover, the higher performance rate and lower average centroiding estimation error of near 0.045 for 400 simulated images compared to other algorithms show the high capability of the proposed night sky star imageprocessing algorithm. (c) 2014 Optical Society of America
In the field of non-destructive testing, Terahertz (THz) tomography is a modern imaging technique permitting 3D inspection of opaque objects. A tomographic procedure reconstructs a 3D volume of the acquired object by ...
详细信息
In the field of non-destructive testing, Terahertz (THz) tomography is a modern imaging technique permitting 3D inspection of opaque objects. A tomographic procedure reconstructs a 3D volume of the acquired object by intersecting the data contained on the projection set. This depth information is extracted from several projections acquired around the object at different viewing angles. This property has made THz tomography a complementary technique to X-Rays. Several reconstruction methods have been investigated for THz tomography [1] but they must be adapted to THz wave properties. For monochromatic source, Beer-Lambert law describes the attenuation encountered by THz waves through the sample and measured on the detector, when reflexion and refraction effects are neglected. Then, as their complements in X-Ray tomography, we investigate in this paper on a Maximum-Likelihood expectation-maximization for TRansmission tomography (ML-TR) compatible with THz radiations. This method, based on Poisson distribution model of measured radiations, takes into account the Gaussian propagation of THz beam [2] and allows introducing some a priori knowledge about the imaged object. Especially, we focus on the implementation denoted Ordered Subsets Convex (OSC) algorithm since it has an efficient convergence rate despite of the noise level and the sparsity of acquired data [3]. We discuss how this new reconstruction is able to estimate physical properties of samples acquired with a 100GHz/300GHz scanner in addition to the 3D reconstruction. Moreover, we present an innovative data and imageprocessing sequence to perform non-destructive inspection from 3D terahertz (THz) images. After a 3D tomographic reconstruction of a sample, a preset segmentation affords the different regions of interest (ROI) composing the inert part of sample. Then a 3D visualization and dimensional measurements could be performed on these ROI, separately, in order to provide new informations of the studied sam
When a marine target is detected by a mid-infrared detector on a sunny day, the target's information could be lost if it is located in sun glint. Therefore, we developed a new mid-infrared imaging system capable o...
详细信息
When a marine target is detected by a mid-infrared detector on a sunny day, the target's information could be lost if it is located in sun glint. Therefore, we developed a new mid-infrared imaging system capable of effectively detecting marine targets in regions of strong sun glint, which is presented in this report. Firstly, the theory of the analysis methods employed in different detection scenarios is briefly described to establish whether one or two polarizers should be utilized to suppress further the p-polarized component of sun glint. Secondly, for the case in which a second polarizer is employed, the formula for the optimum angle between the two polarizers is given. Then, the results of our field experiment are presented, demonstrating that the developed system can significantly reduce sun glint and can enhance the contrast of target images. A commonly used imageprocessing algorithm proved capable of identifying a target in sun glint, confirming the effectiveness of our proposed mid-infrared polarization imaging system.
Accurate measurements of oceanic whitecap coverage from whitecap images are required for better understanding air-gas transfer and aerosol production processes. However, this is a challenging task because whitecap pat...
详细信息
Accurate measurements of oceanic whitecap coverage from whitecap images are required for better understanding air-gas transfer and aerosol production processes. However, this is a challenging task because whitecap patches are formed immediately after a wave breaks and are spread over a wide area. The main challenges in designing whitecaps imaging instrument are the small field of view of the camera lens, processing huge numbers of images, recording data over long time periods, and deployment difficulties in stormy conditions. This paper describes the hardware design of a novel high-resolution optical instrument for imaging oceanic whitecaps and the automated algorithm processing the collected images. The instrument was successfully deployed in 2013 as part of the HiWINGS campaign in the North Atlantic Ocean. The instrument uses a fish-eye camera lens to image the whitecaps in a wide angle of view (180°).
This paper presents a rapid approach for assembling gold nanoparticles (AuNPs)-based microstructures using optically-induced electrokinetics. Results showed that number of AuNPs in the assembled microstructures could ...
详细信息
This paper presents a rapid approach for assembling gold nanoparticles (AuNPs)-based microstructures using optically-induced electrokinetics. Results showed that number of AuNPs in the assembled microstructures could be controlled by adjusting the input optically-induced electrokinetics parameters. The formation conditions were experimentally investigated by varying several key electrokinetics parameters, and the results were compared to a numerical simulation of the electrokinetic forces. The experimental results were also analyzed by counting the number of deposited AuNPs in a microstructure using an imageprocessing algorithm. We will show that the optimal parameters for this optoelectronic AuNPs assembly method are electric field frequency range from 9 to 11 kHz with a voltage range of 18-20 V-pp, and an optical exposure time of similar to 120 s. (C) 2014 Optical Society of America
In this paper the influence of the number of lenslets on the performance of image restoration algorithms for the thin observation module by bound optics (TOMBO) imaging system was investigated, and the lenslet number ...
详细信息
In this paper the influence of the number of lenslets on the performance of image restoration algorithms for the thin observation module by bound optics (TOMBO) imaging system was investigated, and the lenslet number was optimized to achieve thin system and high imaging performance. Subimages with different numbers of lenslets were generated following the TOMBO observation model, and image restoration algorithms were applied to evaluate the imaging performance of the TOMBO system. The optimal lenslet number was determined via theoretical performance optimization and verified via experimental comparisons of angular resolutions of two TOMBO systems and a conventional single-lens system. (C) 2014 Optical Society of America
Energy consumption is a major problem in Wireless Sensor Networks (WSNs) because energy resources of sensors are limited. Several protocols have been created to solve this problem. The main objective of these protocol...
详细信息
ISBN:
(纸本)9781424451661
Energy consumption is a major problem in Wireless Sensor Networks (WSNs) because energy resources of sensors are limited. Several protocols have been created to solve this problem. The main objective of these protocols is to maximize the connectivity and network lifetime. Therefore, the choice of the routing algorithm that delivers packets in a wireless sensor network has to be done in a way to preserve energy. This paper presents a novel adaptive routing algorithm based on imageprocessing algorithm, which utilizes the gradient to select a more energy efficient path.
This paper discusses the history of the appearance and development of structural image analysis. The characteristic disadvantages and advantages of the structural methods that are used and the prerequisites for improv...
详细信息
This paper discusses the history of the appearance and development of structural image analysis. The characteristic disadvantages and advantages of the structural methods that are used and the prerequisites for improving them are analyzed for each of the historical stages. The material culminates with a description of the features of the organization and possibilities of the optimum modern algorithms for structural analysis and a treatment of directions in which they can be improved further. (C) 2015 Optical Society of America.
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...
详细信息
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
暂无评论