共查询到20条相似文献,搜索用时 93 毫秒
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详细介绍了一种基于相移结构光照明的浮雕成像技术,对该成像技术的原理和成像特性进行了实验研究,并采用相移结构光照明的方法实现彩色浮雕成像。实验中,将多幅相移正弦条纹光场斜投射到被拍摄物体上,数码相机依次拍摄被照明的物体,再利用拍摄到的多幅相移图像,通过计算的方法重建出所需要的图像。理论分析和实验结果表明,相移结构光照明成像技术能有效地消去环境不均匀光照的影响,获取的反射率分布图像只与结构光照明有关,突显了斜投射照明所形成的阴影,图像的明暗变化反映出物体表面的法线变化,因而在视觉上形成了明显的浮雕效果。 相似文献
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相移数字全息中的相移准确性决定了重建结果的质量,本文提出了在二步相移数字全息中实现准确相移的方法.该方法使用数字电压源开环控制普通的压电陶瓷微位移器,通过连续以微小的间隔来改变施加在压电陶瓷微位移器上的电压,可以获得一系列对应于不同相移角的全息图像,进而可以利用这些全息图像重建出来物光波在全息面上的强度分布.实验中采用已被CCD直接记录的物光波在全息面上的强度分布作为标准来评价前面重建结果的质量,计算了这些重建结果和评价标准之间的相关系数,结果表明相关系数达到最大时对应的全息图具有准确的相移角π/2.实验中比较了使用所确定准确相移角和理论相移角分别重建出来物光波的质量,计算机模拟和实验的结果证实了该方法的有效性. 相似文献
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系统研究了两步相移数字全息干涉术中相移误差引起的波前再现误差的计算和校正方法. 基于衍射物光相位分布的随机性和振幅相位的相互独立性原理,介绍了相移数字全息中物光波前再现误差的表达形式,推导出步长为π/2的两步算法中物光重建误差的表达式. 通过进一步分析这一重建误差的结构和特点,结合物光表达式,给出了自动校正相移误差引起的波前重建误差的校正方法. 该方法无需增加测量,在未知相移误差大小的情况下,只对标准两步相移算法恢复的物光复振幅进行处理就可以实现对物光振幅和相位的同时校正. 计算机模拟结果表明,校正后可将
关键词:
相移干涉术
数字全息
物光重建
误差校正 相似文献
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本文报道了一项称为载波相移全息干涉计量的自动相位估算的新技术。该技术的主要特点是不同相移的条纹图案可用双曝光全息重视。这样即可用来对与时间相关的问题进行自动相位估算。 相似文献
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A polychromatic correlation detection technique by complex spatial filtering is presented. This technique utilizes a diffraction grating and three co-lineared (red, green, and blue) coherent sources. The technique of complex spatial filter synthesis for the polychromatic corelation detection is demonstrated. This technique offers true color correlation detection which is very suitable for color signal recognition and identification. The correlation diffraction efficiency with this technique is generally higher than that of the wavelength-multiplexed technique. Several interesting experimental demonstrations of this color signal correlation detection scheme are provided. Finally we note that this color signal detection technique is a simple and versatile processing technique which has broad range of applications of complex color signal detection, recognition and identification. 相似文献
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介绍了一种碳纳米管表面增强散射的新方法。该方法消除了溶剂的干扰,保证了结果的准确性,理论分析和实验结果证明该方法是正确的,可行的。 相似文献
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Yaohui Gao Chia-En Yang Yunching Chang Jimmy Yao Stuart Yin Claire Luo Paul Ruffin Christina Brantley Eugene Edwards 《Applied physics. B, Lasers and optics》2012,109(1):133-136
A technique of enhancing and broadening terahertz (THz) wave radiation from large aperture photoconductive (PC) antenna is presented in this paper. In this technique, the PC antenna is excited by both the optical and previously generated THz pulses by a laser-induced air plasma created in front of PC antenna and an enhanced and broadened THz wave signal is obtained. The theoretical and experimental investigation shows that the superposition is the main mechanism for this enhancement. The technique shown in this paper can be very useful for THz imaging and spectroscopy. 相似文献
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激光纹影技术特别适合检测激波后高温快速反应的反应速率。本文建立的激光纹影系统能很好地从事化学动力学研究。并对Kiefer的激光纹影系统进行了改进,改进后的激光纹影系统测定结果稳定,操作简便。 相似文献
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Distributed point source method (DPSM) is gradually gaining popularity in the field of non-destructive evaluation (NDE). DPSM is a semi-analytical technique that can be used to calculate the ultrasonic fields produced by transducers of finite dimension placed in homogeneous or non-homogeneous media. This technique has been already used to model ultrasonic fields in homogeneous and multi-layered fluid structures. In this paper the method is extended to model the ultrasonic fields generated in both fluid and solid media near a fluid-solid interface when the transducer is placed in the fluid half-space near the interface. Most results in this paper are generated by the newly developed DPSM technique that requires matrix inversion. This technique is identified as the matrix inversion based DPSM technique. Some of these results are compared with the results produced by the Rayleigh-Sommerfield integral based DPSM technique. Theory behind both matrix inversion based and Rayleigh-Sommerfield integral based DPSM techniques is presented in this paper. The matrix inversion based DPSM technique is found to be very efficient for computing the ultrasonic field in non-homogeneous materials. One objective of this study is to model ultrasonic fields in both solids and fluids generated by the leaky Rayleigh wave when finite size transducers are inclined at Rayleigh critical angles. This phenomenon has been correctly modelled by the technique. It should be mentioned here that techniques based on paraxial assumptions fail to model the critical reflection phenomenon. Other advantages of the DPSM technique compared to the currently available techniques for transducer radiation modelling are discussed in the paper under Introduction. 相似文献
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A phase pre-emphasis technique used in an all-optical sampling orthogonal frequency division multiplexing (AOS-OFDM) system is proposed and demonstrated. With the application of this technique, 50-Gb/s AOS-OFDM data are successfully transmitted over 20-km uncompensated single-mode fiber (SMF) with real-time direct-detection. The constructive interference effect between symbols is decreased with this technique. 相似文献