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Current Developments in Lens Design and Optical Engineering XX最新文献

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Design of a head-mounted display with freeform mirrors 自由镜头戴式显示器的设计
Pub Date : 2019-08-30 DOI: 10.1117/12.2531787
Congshan Rui, Chun-mei Zeng, Tian-tian Hu, Suo-dong Ma
A head-mounted display (HMD) requires a large field of view (FOV) and a large exit pupil diameter while maintaining a compact structure. In this paper, we show a head-mounted display design comprising two freeform mirrors covering a 28° full field-of-view with an eye relief of 15mm. The simplified partial differential equation (PDE) method is applied in the design of a two-mirror HMD system. Then the data points on the unknown freeform mirrors are calculated using the rays from multiple fields and are used to construct the freeform mirrors in the HMD system, which is taken as a starting point. This simplified partial differential equation method makes calculations easier. The anamorphic surface and the XY polynomial freeform surface are used in the two freeform mirrors for improving the image quality, respectively. The optimization strategy is also described in detail. The final HMD system operates at F/3.75 with 8mm exit pupil diameter achieving good imaging performance.
头戴式显示器(HMD)需要大的视野(FOV)和大的出口瞳孔直径,同时保持紧凑的结构。在本文中,我们展示了一种头戴式显示器设计,该设计包括两个自由曲面镜,覆盖28°全视野,眼距为15mm。将简化偏微分方程(PDE)方法应用于双镜HMD系统的设计。然后利用多场射线计算未知自由曲面反射镜上的数据点,并以此为起点构建HMD系统中的自由曲面反射镜。这种简化的偏微分方程方法使计算更容易。为了提高成像质量,两个自由曲面分别采用变形曲面和XY多项式自由曲面。并对优化策略进行了详细的描述。最终的HMD系统在F/3.75下工作,出瞳直径为8mm,具有良好的成像性能。
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引用次数: 0
Determination of rough microstructures on the surface of metals using the light scattering method in waveguides 用波导中的光散射法测定金属表面粗糙微结构
Pub Date : 2019-08-30 DOI: 10.1117/12.2526123
N. Espinosa, C. Vega, Jorge Alvarez, P. Leon, J. Vila
In this paper, we present the main results for the theoretical, numerical and experimental analysis of a new method to measure the roughness of metal surfaces. The requirements for a waveguide optical resonator, which is the main optical node of the device implementing this method, have been developed. A comparative analysis of two different designs of an optical node is performed. The energy spectra of the roughness of various surfaces were measured. As a result of the research, the main advantages of the method under consideration and practical recommendations are provided to improve the design of the device that implements this method.
本文介绍了一种测量金属表面粗糙度新方法的理论、数值和实验分析的主要结果。波导光谐振器是实现该方法的主要光节点,对波导光谐振器的要求已经确定。对两种不同设计的光节点进行了比较分析。测量了不同表面粗糙度的能谱。研究的结果是,考虑了该方法的主要优点,并提出了实用的建议,以改进实施该方法的设备的设计。
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引用次数: 0
Fractal analysis for classification of breast lesions 乳腺病变分形分析
Pub Date : 2019-08-30 DOI: 10.1117/12.2531201
L. Alvarado-Cruz, M. Delgadillo-Herrera, C. Toxqui-Quitl, A. Padilla-Vivanco, R. Castro-Ortega, M. Arreola-Esquivel
Nowadays, breast lesions are a common health problem among women. Breast thermograms are images recorded by digital-optical systems with high resolution that use infrared technology in order to show vascular and temperature changes. In the present work, we study benign and malignant breast lesions shape by means of fractal analysis. The Fractal Dimension (FD) is calculated with the Box Counting method and the Hurst exponent is obtained using the Wavelet coefficients and the Detrending Moving Average algorithm. These algorithms was applied to synthetic images and breast thermograms. The Fractal Dimension value is used for patient classification with or without breast injury. The proposed methodology was applied to the Database For Mastology Research (DMR) in order to classify thermographic images. The FD of ROIs for breast thermograms was calculated. Results shows that the FD BCM values ranges from [0.45,0.81] in 4 healthy cases and from [0.92,1.33] in 4 unhealthy cases.
如今,乳房病变是妇女中常见的健康问题。乳房热像图是由高分辨率的数字光学系统记录的图像,该系统使用红外技术来显示血管和温度变化。在本工作中,我们用分形分析的方法研究乳腺良恶性病变的形态。采用盒计数法计算分形维数(FD),采用小波系数和去趋势移动平均算法计算Hurst指数。这些算法被应用于合成图像和乳房热像图。分形维数值用于患者有无乳房损伤的分类。提出的方法应用于乳腺研究数据库(DMR),以便对热成像图像进行分类。计算乳腺热像图roi的FD。结果:4例健康患者FD BCM值在[0.45,0.81]之间,4例不健康患者FD BCM值在[0.92,1.33]之间。
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引用次数: 3
Deployment of combined higher order aberrations to extend the depth of focus of lenses 组合高阶像差的部署,以延长镜头的聚焦深度
Pub Date : 2019-08-30 DOI: 10.1117/12.2530144
D. Monteiro, R. F. D. O. Costa, Luiz Melk de Carvalho
This work proposes a lens topology based on the addition of combined high-order aberrations to its posterior surface to achieve an extended depth of focus. The added terms are vertical and horizontal coma and spherical aberration, described by Zernike polynomials. We compare the herein proposed IOL with three classes of IOLs available on the market: monofocal, multifocal and extended depth of focus (EDoF). The proposed lens showed better results off the image plane, confirming the increase in the depth of focus when compared with the monofocal IOL. This is clearly observed with the extended Through-Focus-MTF maps that allow the evaluation of several spatial frequencies at different image planes. The fabricated prototype has similar performance to the Tecnis Symfony, a commercial lens with extended depth of focus. And when the Modulation Transfer Function (MTF) is compared to multifocal lenses, a niche where lenses with extended depth of focus can be possible substitutes, the performance of the herein proposed lens was higher in every case considered.
这项工作提出了一种基于在后表面添加组合高阶像差的透镜拓扑,以实现扩展的聚焦深度。所增加的项是用泽尼克多项式描述的垂直和水平彗差和球差。我们将本文提出的人工晶状体与市场上现有的三种类型的人工晶状体进行比较:单焦点、多焦点和扩展焦深(EDoF)。所提出的晶体在图像平面外显示出更好的结果,证实了与单焦点IOL相比,焦点深度的增加。这可以通过扩展的透焦- mtf地图清楚地观察到,该地图允许在不同的图像平面上评估几个空间频率。制造的原型具有与Tecnis Symfony类似的性能,这是一种具有扩展焦距的商业镜头。当将调制传递函数(MTF)与多焦透镜进行比较时,在每个考虑的情况下,本文提出的透镜的性能都更高,而多焦透镜是具有扩展焦深的透镜的可能替代品。
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引用次数: 0
Fundus camera versus smartphone camera attachment: image quality analysis 眼底相机与智能手机相机附件:图像质量分析
Pub Date : 2019-08-30 DOI: 10.1117/12.2528965
Nicole Barritt, Mohana Kuppuswamy Parthasarathy, Ibrahim Faruq, J. Zelek, V. Lakshminarayanan
Fundus cameras are the current clinical standard for capturing retinal images, which are used to diagnose a variety of sight-threatening conditions. Traditional fundus cameras are not easily transported, making them unsuitable for field use. In addition, traditional fundus cameras are expensive. Due to this, a variety of technologies have been developed such as the D-EYE Digital Ophthalmoscope (D-EYE Srl, Padova, Italy) which is compatible with various cellphone cameras. This paper reports on the comparison of the image quality of the Nidek RS-330 OCT Retina Scan Duo (Nidek, Tokyo, Japan) and the D-EYE paired with an iPhone 6 (Apple, Cupertino, USA). Twenty-one participants were enrolled in the study of whom 14 underwent nonmydriatic and mydriatic imaging with the D-EYE and the Nidek. Seven participants underwent nonmydriatic imaging with the D-EYE and the Nidek. The images were co-registered and cropped so that the region of interest was equal in both the D-EYE and Nidek images, as the D-EYE had a smaller field of view. Using the Nidek image as the reference, objective full-reference image quality analysis was performed. Metrics such as structural similarity index and peak signal noise ratio were obtained. It was found that the image quality of the D-EYE is limited by the attached iPhone camera, and is lower when compared to the Nidek. Quantification of the differences between the D-EYE and Nidek allows for targeted development of smartphone camera attachments that can help to bridge the current gap in image quality.
眼底相机是目前用于捕捉视网膜图像的临床标准,用于诊断各种视力威胁状况。传统的眼底相机不容易运输,不适合野外使用。此外,传统眼底相机价格昂贵。因此,开发了多种技术,如D-EYE数字检眼镜(D-EYE Srl,帕多瓦,意大利),与各种手机摄像头兼容。本文报道了Nidek RS-330 OCT视网膜扫描Duo (Nidek,东京,日本)和D-EYE与iPhone 6(苹果,库比蒂诺,美国)配对的图像质量的比较。21名参与者参加了这项研究,其中14名接受了D-EYE和Nidek的无肌痛和有肌痛成像。7名参与者接受了D-EYE和Nidek的非散体成像。由于D-EYE具有较小的视野,因此这些图像被共同配准和裁剪,因此D-EYE和Nidek图像中的感兴趣区域是相等的。以Nidek图像为参照物,进行客观的全参照物图像质量分析。得到了结构相似指数、峰值信噪比等指标。结果发现,D-EYE的图像质量受到iPhone相机的限制,比Nidek低。对D-EYE和Nidek之间的差异进行量化,可以有针对性地开发智能手机相机附件,帮助弥合目前在图像质量方面的差距。
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引用次数: 4
Application of GPUs in optical design software gpu在光学设计软件中的应用
Pub Date : 2019-08-30 DOI: 10.1117/12.2526861
B. Mischuck, E. Page, A. Croce
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引用次数: 0
Freeform optics design of primary lens for uniform irradiance distribution of a concentrator photovoltaic system 聚光光伏系统辐照度均匀分布主透镜的自由曲面光学设计
Pub Date : 2019-08-30 DOI: 10.1117/12.2531251
T. Pham, N. Duy, N. Vu, Seoyong Shin
In this paper, a primary lens of concentrator photovoltaic (CPV) system is designed by using freeform optics. The designed lens is constructed based on a basic idea of a combination of Fresnel lens and freeform optics, in which the lens is divided into an array of sub-lenses, which are designed using the conservation of optical path length and the edge ray theorem to get uniform irradiance distribution over the receiver. In this design, every sub-lens is designed to guide the direct sunlight over the receiver with uniform irradiance so that the whole of the primary lens will converge uniformly the direct sunlight over the receiver. The structure of the lens is designed firstly by using Matlab program for every sub-lens. The Matlab data of the designed lens structure is then used to build the three-dimensional (3D) lens in LightTools™ software. The ray tracing technique in LightTools™ software is used to find out the optimum structure of the freeform lens. Furthermore, the simulation is performed to estimate the efficiency of the lens as a concentrator of a CPV system by using the light source with the sunlight spectrum. The designed lens can achieve high geometrical concentration ratio and uniform irradiance distribution over the receiver. The simulation results show that the lens can easily reach a high concentration ratio (494 times) with uniform irradiance distribution and good optical efficiency (86%).
本文采用自由曲面光学技术设计了聚光光伏(CPV)系统的一次透镜。设计的透镜基于菲涅耳透镜与自由曲面光学相结合的基本思想,将透镜划分为一组子透镜,利用光程长度守恒和边缘射线定理进行设计,以获得均匀的辐照度分布。在这种设计中,每个副透镜都被设计成以均匀的辐照度引导直射到接收器上的阳光,从而使整个主透镜均匀地汇聚到接收器上的直射阳光。首先利用Matlab程序对各子镜头进行了结构设计。然后使用设计的透镜结构的Matlab数据在LightTools™软件中构建三维(3D)透镜。使用LightTools™软件中的光线追踪技术来找出自由曲面透镜的最佳结构。在此基础上,利用具有太阳光光谱的光源对聚光系统的聚光效率进行了仿真计算。所设计的透镜具有较高的几何聚光比和均匀的辐照度分布。仿真结果表明,该透镜具有较高的聚光比(494倍),辐照度分布均匀,光学效率高达86%。
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引用次数: 3
Normalized difference indices in Landsat 5 TM satellite data Landsat 5 TM卫星数据的归一化差指数
Pub Date : 2019-08-30 DOI: 10.1117/12.2532322
M. Delgadillo-Herrera, M. Arreola-Esquivel, C. Toxqui-Quitl, A. Padilla-Vivanco
Urban growth, deforestation, water resources and thawing of the poles due to globe worming are topics of interest in the research community. Normalize difference indices are utilized in remote sensing to analyzed and classify surface cover types. In this paper research, a multispectral satellite data from Landsat 5 TM is preprocessing, in order to addresses and evaluates accuracy of Normalized difference Built-up Index (NDBI), Normalized Difference Vegetation Index (NDVI), Automated Water Extraction Index (AWEI) and Normalized Difference Snow Index (NDSI) at different time scenes. A quantitative statistical pixel percentages of build-up, vegetation cover, snow/ice and water body is given in this study for different periods of time.
城市发展、森林砍伐、水资源和由于全球蠕虫造成的两极融化是研究界感兴趣的话题。遥感中利用归一化差分指数对地表覆盖类型进行分析和分类。本文通过对Landsat 5 TM多光谱卫星数据进行预处理,对不同时间场景下归一化差异建筑指数(NDBI)、归一化差异植被指数(NDVI)、自动取水指数(AWEI)和归一化差异积雪指数(NDSI)的精度进行求解和评价。本研究给出了不同时期的堆积、植被覆盖、冰雪和水体的定量统计像元百分比。
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引用次数: 5
Silicon Fresnel lens fabricated using greyscale lithography 采用灰阶光刻技术制造的硅菲涅耳透镜
Pub Date : 2019-08-30 DOI: 10.1117/12.2530649
Chengpo Chen, J. Karp, Tim Toepfer, O. Boomhower, J. Kretchmer, S. Goswami, Sachin Dekate, L. Tsakalakos
A silicon Fresnel lens was designed and fabricated using a greyscale lithography technique to shape optical emissions from an edge-emitting semiconductor diode laser. The laser beam was collimated in the fast axis and allowed a ±3° divergence in the slow axis along with bias angle accomplished through lens decentering. The lens had an aperture of 6.8 mm × 2.2 mm and 1 mm in total thickness. The lens was first designed as a contiguous surface using conventional raytracing methods, and then converted to a Fresnel sag model with an etch depth of 6.25 micrometers. The sag model along with the manufacturing tolerances were fed back through numerical tools to refine the design and modify the lens shape and laser position. Optical profilometry of fabricated lens element found deviations from design and nonuniformity across the entire aperture, with over-etching in the center and under-etching toward the edge of the lens. Characterization of the fabricated lenses showed less than 5% deviation in etch depth. Collimation performance was measured to be less than 2 milliradians, which was in close agreement with design models. Greyscale fabrication of the lens element enabled complex curvatures to be combined and provided a compact solution for direct, single optic coupling of diode laser to free-space projection.
采用灰阶光刻技术,设计并制造了一种硅菲涅耳透镜,用于边发射半导体二极管激光器的光发射。激光束在快轴上准直,在慢轴上允许±3°发散,并通过透镜离心实现偏置角。透镜孔径为6.8 mm × 2.2 mm,总厚度为1mm。首先采用传统的光线追踪方法将透镜设计为连续表面,然后将其转换为蚀刻深度为6.25微米的菲涅耳凹陷模型。通过数值工具反馈凹坑模型和加工公差,改进设计,修改透镜形状和激光位置。制造透镜元件的光学轮廓测量发现偏离设计和整个孔径的不均匀性,在中心有过蚀刻,在透镜边缘有欠蚀刻。制备的透镜的刻蚀深度偏差小于5%。测量的准直性能小于2毫弧度,与设计模型基本一致。透镜元件的灰度制造使复杂的曲率能够组合,并为二极管激光到自由空间投影的直接单光学耦合提供了紧凑的解决方案。
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引用次数: 1
General formula for aspheric collimator lens design free of spherical aberration 无球差非球面准直透镜设计的一般公式
Pub Date : 2019-08-30 DOI: 10.1117/12.2527341
Rafael G. González-Acuña, J. Gutiérrez-Vega
We present the general formula to generated aspheric collimator lens free of spherical aberration and astigmatism. The presented formula describes the second surface of the aspheric singlet such as it correct the spherical aberration generated and astigmatism by the first surface of the singlet.
给出了无球像差和无像散的非球面准直透镜的一般公式。该公式描述了非球面单透镜的第二面,并对单透镜第一面产生的球差和像散进行了校正。
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引用次数: 4
期刊
Current Developments in Lens Design and Optical Engineering XX
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