共查询到18条相似文献,搜索用时 125 毫秒
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光学相干层析系统相干传递函数研究 总被引:5,自引:1,他引:4
在弱物体近似下从成像系统角度对光学相干层析测量技术进行了理论研究。分析了该技术测量样品纵深结构时图像的形成机理。结果表明它相当于一复振幅线性平移不变系统,从而可用相干传递函数描述系统性能,所得相干传递函数表明系统具有低通特性,半峰值带宽△k=2△λ/λ^2。由于物体频谱整体平移了1/λ,测量的是纵向结构的高频信息。本文的工作为定量分析光学相干层析对未知结构的测量结果及进一步提高空间分辨率提供了理论 相似文献
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设计了一个大扫描视场的折衍混合红外共形光学系统,共形成像系统工作波段为3.7~4.8 m,相对孔径为1/2,焦距为120 mm,扫描视场为40。由于共形光学系统具有大偏心、大倾斜光学特性,像差校正难度较大,设计中采用固定校正镜和折衍混合混合结构校正了共形光学元件的像差,引入了非球面和衍射面有效消除了各个扫描视场的像差。设计结果表明:光学系统光阑与探测器冷光阑重合,满足100%冷光阑效率。在40扫描视场范围内,共形光学系统的光学传递函数曲线接近衍射极限,成像良好。 相似文献
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光学综合孔径望远镜成像分析及计算机仿真 总被引:13,自引:9,他引:4
阐述了光学综合孔径(OSA)望远镜成像原理以及综合孔径望远镜的几种实现形式;采用快速傅里叶变换(FFT)算法得到了任意子孔径综合模式下的点扩展函数(PSF)和光学传递函数(OTF)分布;从子孔径结构排列、共相位、图像恢复几个方面论述了光学综合孔径的成像特征。初步分析了稀疏率、填充因子、“实际截止频率”等因素对光学综合孔径望远镜成像的影响。分析和仿真结果表明:光学综合孔径通过相干成像不但可以突破传统单孔径系统的口径局限获得极高的成像分辨率,而且对于实现空间光学遥感系统轻量化和模块化都具有重要意义。 相似文献
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折反射全景光学成像系统具有平面对称光学系统的成像特性,提出应用光焦度控制方程和超大视场光学系统六阶波像差理论来初步确定系统结构初始参数,在此结构基础上,应用Zemax软件对其进行设计和优化,得到了一款仅由1块偶次非球面反射镜和6块折射透镜组成的折反射全景光学成像系统。该系统工作在可见光波段,全视场角范围为12°~178°,F数为3.5,其像差得到了较理想校正,调制传递函数在空间频率40 lp/mm处均大于0.37,成像性能较好,满足实际应用要求。同时,对设计的系统进行了公差分析。 相似文献
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《中国物理快报》2016,(4)
An optical transfer function(OTF) reconstruction model is first embedded into incoherent Fourier ptychography(IFP).The leading result is a proposed algorithm that can recover both the super-resolution image and the OTF of an imaging system with unknown aberrations simultaneously.This model overcomes the difficult problem of OTF estimation that the previous IFP faces.The effectiveness of this algorithm is demonstrated by numerical simulations,and the superior reconstruction is presented.We believe that the reported algorithm can extend the original IFP for more complex conditions and may provide a solution by using structured light for characterization of optical systems' aberrations. 相似文献
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B. M. Watrasiewicz 《Optics & Laser Technology》1972,4(6):288-292
This contribution deals with phase and amplitude filters used in coherent, partially coherent and incoherent illumination both for improvement of optical images and for detection of similarities (correlation). Other types of filters such as intensity filters, phase only filters etc. will be also discussed where appropriate. Most of the space, however, will be devoted to optical filtering in coherent illumination. 相似文献
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The mutual intensity function plays a major role in characterizing quasi-monochromatic, partially coherent optical signals. We propose to use the mutual intensity as a carrier of information to avoid speckle noise in coherent illumination systems and to permit the use of complex functions that are prohibited spatially incoherent sources. To do this we require methods for encoding the information as a coherence function. An optical system for synthesizing a beam with a given mutual intensity function is proposed. The optical system permits the synthesis of any desired mutual intensity function. The illumination is supplied by a quasi-monochromatic, spatially incoherent source. Experimental results demonstrate the performance of this system for several cases. 相似文献
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提出一种用非相干光系统识别彩色图像的方法,将脸色图像分解成三个单色像处理,设计一可实现的仅相位光学传递函数,对其进行带能优化,人而提高信噪比并使相关峰锐化,通过一对滤波器来合成该光学传递函数,获得了采色图像相关识别的实验结果。 相似文献
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G. N. Mal’tsev 《Optics and Spectroscopy》2000,89(5):805-809
Results of calculations of the resolving power (according to Foucault) of optoelectronic imaging systems with incoherent and coherent illumination under the conditions of atmospheric phase distortions are presented. It is suggested that incoherent optical images are formed in the case of incoherent illumination and speckle images are formed in the case of coherent illumination. The shape of objects observed is estimated from these images. The resolving powers are shown to be practically the same in the formation of incoherent optical images and speckle images in the case of strong phase distortions and smoothing of images by a matrix photodetector. At the same time, the limiting resolving power in the formation of incoherent optical images is twice as large as in the formation of speckle images. 相似文献
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Using the beam fanning effect in a BaTiO3 crystal, we propose two simple set-ups to perform the function of an optical image combiner and an optical AND gate respectively. The optical image combiner combines two mutually coherent as well as mutually incoherent patterns transmitted to it separately into a single coherent pattern. This set-up can also be used as an optical OR gate. For the AND gate, the two input signals may also be mutually coherent or incoherent. Experimental results showed the response time of these two devices to range from 0.01 second to 2.5 seconds. 相似文献
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ANALYSIS OF THE GENERAL EFFECTS IN DOUBLE-GRATING DIFFRACTION-INTERFERENCE SYSTEM 总被引:2,自引:0,他引:2 下载免费PDF全文
Based on the ambiguity function, the optical phenomena of the double-gearing diffraction-interference system are analysed with partially coherent illumination. Different patterns are observed on the observation plane when the optical elements are placed in their proper positions. Detailed discussions on the two extremes of coherence are given. Conclusions could be obtained about the Lau effect, the generalized Lau effect, the incoherent grating-lens imaging, the Talbot effect, the joint-Talbot effect and the generalized joint-Talbot effect. Some special cases are also verified by experiments. 相似文献