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Adaptive optics (AO) has been proved as a powerful means for high resolution imaging of human retina.Because of the pixel number of charge-coupled device (CCD) camera, the field of view is limited to 1°.In order to have image of capillaries around vivo human fovea, we use mosaic method to obtain high resolution image in area of 6°× 6°. Detailed structures of capillaries around fovea with resolution of 2.3μm are clearly shown. Comparison shows that this method has a much higher resolution than current clinic retina imaging methods. 相似文献
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Hermann B Fernández EJ Unterhuber A Sattmann H Fercher AF Drexler W Prieto PM Artal P 《Optics letters》2004,29(18):2142-2144
Merging of ultrahigh-resolution optical coherence tomography (UHR OCT) and adaptive optics (AO), resulting in high axial (3 microm) and improved transverse resolution (5-10 microm) is demonstrated for the first time to our knowledge in in vivo retinal imaging. A compact (300 mm x 300 mm) closed-loop AO system, based on a real-time Hartmann-Shack wave-front sensor operating at 30 Hz and a 37-actuator membrane deformable mirror, is interfaced to an UHR OCT system, based on a commercial OCT instrument, employing a compact Ti:sapphire laser with 130-nm bandwidth. Closed-loop correction of both ocular and system aberrations results in a residual uncorrected wave-front rms of 0.1 microm for a 3.68-mm pupil diameter. When this level of correction is achieved, OCT images are obtained under a static mirror configuration. By use of AO, an improvement of the transverse resolution of two to three times, compared with UHR OCT systems used so far, is obtained. A significant signal-to-noise ratio improvement of up to 9 dB in corrected compared with uncorrected OCT tomograms is also achieved. 相似文献
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利用变迹术和相干门相结合实现光学相干层析成像术轴向超分辨 总被引:4,自引:2,他引:2
光学相十层析成像(光学相干层析成像术)的轴向分辨力由光源带宽和探测光束的聚焦条件共同决定。提高光学相干层析成像术轴向分辨力的方法主要基于带宽光源技术。提出了一种将变迹术与光学相十层析成像术相干门有机结合的方法来提高其轴向分辨力。通过适当形式的光瞳滤波器.使光学相干层析成像术系统轴向响应的主瓣宽度缩小到相干门之内,而其旁瓣则处于相干门之外.不对相干成像产生有效贡献。这样.就能在光源带宽不变的条件下,有效提高光学相十层析成像术的轴向分辨力,避免了采用宽带光源所带来的费用昂贵和系统复杂等缺陷。 相似文献
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A high-speed (47,000 A-scans/s), ultrahigh axial resolution Fourier domain optical coherence tomography (OCT) system for retinal imaging at approximately 1060 nm, based on a 1024 pixel linear array, 47 kHz readout rate InGaAs camera is presented. When interfaced with a custom superluminescent diode (lambda(c) = 1020 nm, Deltalambda = 108 nm, Pout = 9 mW), the system provides 3.3 microm axial OCT resolution at the surface of biological tissue, approximately 4.5 microm in vivo in rat retina, approximately 5.7 microm in vivo in human retina, and 110 dB sensitivity for 870 microW incident power and 21 mus integration time. Retinal tomograms acquired in vivo from a human volunteer and a rat animal model show clear visualization of all intraretinal layer and increased penetration into the choroid. 相似文献
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用于活体人眼视网膜观察的自适应光学成像系统 总被引:16,自引:4,他引:16
利用自适应光学技术,研制了两套活体人眼视网膜高分辨力成像系统,在实时校正人眼波前误差的基础上,实现活体人眼视网膜细胞尺度的高分辨力成像。这两套系统分别采用19和37单元小型压电变形反射镜作为波前校正元件,哈特曼-夏克(Hartmann-Shack)波前传感器测量波前误差,用眼底反射的半导体激光作为波前探测的信标。在用计算机控制自适应光学系统实现人眼波前误差校正后,触发闪光灯照明视网膜,用CCD相机记录视网膜的高分辨力图像。校正后的残余波前误差的均方根值已分别小于1/6和1/10波长,相当于视网膜上成像分辨力分别为3.4μm和2.6μm,接近衍射极限。试验表明37单元系统的成像质量更好。 相似文献
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Combined confocal scanning ophthalmoscopy/en face T-scan-based ultrahigh-resolution optical coherence tomography (OCT) of the human retina in vivo is reported for the first time to our knowledge. The system uses a superluminescent diode-based broadband source, which gives an axial resolution of 3.2 microm in the retina. We demonstrate acquisition of T-scan-based OCT B-scan and simultaneous confocal/C-scan images of the human retina of large lateral size (covering a field of up to 20 degrees ) at a frame rate of 2Hz. 相似文献
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Retinal axial focusing and multi-layer imaging with a liquid crystal adaptive optics camera 下载免费PDF全文
With the help of adaptive optics(AO) technology, cellular level imaging of living human retina can be achieved.Aiming to reduce distressing feelings and to avoid potential drug induced diseases, we attempted to image retina with dilated pupil and froze accommodation without drugs. An optimized liquid crystal adaptive optics camera was adopted for retinal imaging. A novel eye stared system was used for stimulating accommodation and fixating imaging area. Illumination sources and imaging camera kept linkage for focusing and imaging different layers. Four subjects with diverse degree of myopia were imaged. Based on the optical properties of the human eye, the eye stared system reduced the defocus to less than the typical ocular depth of focus. In this way, the illumination light can be projected on certain retina layer precisely.Since that the defocus had been compensated by the eye stared system, the adopted 512 × 512 liquid crystal spatial light modulator(LC-SLM) corrector provided the crucial spatial fidelity to fully compensate high-order aberrations. The Strehl ratio of a subject with-8 diopter myopia was improved to 0.78, which was nearly close to diffraction-limited imaging. By finely adjusting the axial displacement of illumination sources and imaging camera, cone photoreceptors, blood vessels and nerve fiber layer were clearly imaged successfully. 相似文献
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Srinivasan VJ Huber R Gorczynska I Fujimoto JG Jiang JY Reisen P Cable AE 《Optics letters》2007,32(4):361-363
High-speed, high-resolution optical coherence tomography (OCT) imaging of the human retina is demonstrated using a frequency-swept laser at 850 nm. A compact external cavity semiconductor laser design, optimized for swept-source ophthalmic OCT, is described. The laser enables an effective 16 kHz sweep rate with >10 mm coherence length and a tuning range of approximately 35 nm full width at half-maximum, yielding an axial resolution of <7 micro m in tissue. 相似文献
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With the use of adaptive optics(AO), high-resolution microscopic imaging of the living human retina in the single cell level has been achieved. In an AO retinal imaging system, with a small field size (about 1°, 300 μm) the motion of the eye severely affects the stabilization of the real-time video images results in significant distortions of the retina images. Scale-invariant feature transform (SIFT) algorithm is applied to automatically abstract corner points with subpixel resolution and match the points in two frames. With the matched corner points, we estimate and remove the motions of 20 frames of photoreceptor cells and capillary blood vessels, respectively. The maximal translational motion is about 30 and 44 pixels in the 20 frames whose size is 416 × 416 pixels. More general motions can be considered by the SIFT algorithm, but only simple translational motion can be considered by cross-correlation algorithm. 相似文献
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Noninvasive in vivo functional optical imaging of the intact retina is demonstrated by using high-speed, ultrahigh-resolution optical coherence tomography (OCT). Imaging was performed with 2.8 microm resolution at a rate of 24,000 axial scans per second. A white-light stimulus was applied to the dark-adapted rat retina, and the average reflectivities from different intraretinal layers were monitored as a function of time. A 10%-15% increase in the average amplitude reflectance of the photoreceptor outer segments was observed in response to the stimulus. The spatial distribution of the change in the OCT signal is consistent with an increase in backscatter from the photoreceptor outer segments. To our knowledge, this is the first in vivo demonstration of OCT functional imaging in the intact retina. 相似文献
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A fiber-optic-bundle-based optical coherence tomography (OCT) probe method is presented. The experimental results demonstrate this multimode optical fiber-bundle-based OCT system can achieve a lateral resolution of 12 microm and an axial resolution of 10 microm with a superluminescent diode source. This novel OCT imaging approach eliminates any moving parts in the probe and has a primary advantage for use in extremely compact and safe OCT endoscopes for imaging internal organs and great potential to be combined with confocal endoscopic microscopy. 相似文献
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We have developed a novel phase-resolved optical coherence tomography (OCT) and optical Doppler tomography (ODT) system that uses phase information derived from a Hilbert transformation to image blood flow in human skin with fast scanning speed and high velocity sensitivity. Using the phase change between sequential scans to construct flow-velocity imaging, this technique decouples spatial resolution and velocity sensitivity in flow images and increases imaging speed by more than 2 orders of magnitude without compromising spatial resolution or velocity sensitivity. The minimum flow velocity that can be detected with an axial-line scanning speed of 400 Hz and an average phase change over eight sequential scans is as low as 10 microm/s, while a spatial resolution of 10 microm is maintained. Using this technique, we present what are to our knowledge the first phase-resolved OCT/ODT images of blood flow in human skin. 相似文献
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光纤型光学相干层析成像系统的研制 总被引:22,自引:7,他引:15
光学相干层析(OCT)成像技术是一新近发展的高分辨力生物医学成像手段,能非侵入性地对活体内部的结构与生理功能进行可视化观察。采用宽带近红外光源,基于迈克耳孙干涉原理和外差探测方法,建立了单模光纤型光学相干层析成像系统,相干地提取从生物体内部返回的深度分辨的弹性散射光信息,并依此构筑了自然状态下活体组织的二维光学相干层析成像图像和三维光学相干层析成像图像。光纤化设计的光学相干层析成像系统紧凑、灵活,便于与光纤导管、内窥镜和其它成像装置的有机结合,以拓展其观察范围和应用领域。 相似文献
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Shuncong Zhong Yao-Chun Shen Louise Ho Robert K. MayJ. Axel Zeitler Mike EvansPhilip F. Taday Michael PepperThomas Rades Keith C. GordonRonny Müller Peter Kleinebudde 《Optics and Lasers in Engineering》2011,49(3):361-365
Optical coherence tomography (OCT) and terahertz pulsed imaging (TPI) are two powerful techniques allowing high quality cross-sectional images from within scattering media to be obtained non-destructively. In this paper, we report experimental results of using OCT and TPI for quantitatively characterizing pharmaceutical tablet coatings in the thickness range of 10-140 μm. We found that the spectral OCT system developed in-house has an axial resolution of 0.9 μm, and is capable of quantifying very thin coatings in the range of 10-60 μm. The upper limit of 60 μm within the tablet coating and core is owed to the strong scattering of OCT light, which has relatively short wavelengths in the range of 0.5-1.0 μm. On the other hand, TPI utilizes terahertz radiation that has substantially long wavelengths in the range of hundreds of microns, and thus is less prone to the scattering problem. Consequently TPI has been demonstrated to be able to quantify thicker coatings in the range of 40-140 μm and beyond. We concluded that OCT and TPI are two complementary analytical techniques for non-destructive and quantitative characterization of pharmaceutical tablet coatings. 相似文献
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光学相干断层扫描成像新技术OCT 总被引:9,自引:0,他引:9
光学相干层析成像技术(optical coherence tomography,简称OCT)是一种新型成像方法,在生物医学和材料等许多领域有广泛的应用。本文介绍了OCT的基本原理,并给出了用该装置对生物组织样品的成像结果。此外还用计算机图像处理的方法,使得图像分辨率得到了进一步提高。 相似文献
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针对现有成像系统因数据冗余而无法兼顾大视场、高分辨、高效性的问题,结合人眼视网膜变分辨成像和并列式复眼成像原理,设计一种多分辨率成像的复合仿生成像系统.该成像系统按照球面和平面兼顾的曲面布局方式,利用11个相机镜头构建相机阵列,组成了四个等级分辨率的子眼拍摄模块.通过物距100 m的远景实验和物距10 m的近景实验发现,该系统在实现高分辨成像的同时,获得总视场达150.8°×37.8°.多分辨率成像实验结果表明,该系统获取的图像的分辨率从中心视场到边缘视场逐渐降低,并且相较于中心清晰全视场成像,四级分辨率成像的拼接图像数据量减少了17.2倍的数据冗余. 相似文献