共查询到20条相似文献,搜索用时 612 毫秒
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Bayer滤波型彩色相机广泛应用于航天遥感、空间对地观测、环境监测等领域.由于Bayer滤波片造成彩色相机相比黑白相机在像质方面进一步退化,如何对Bayer滤波型彩色相机成像性能全频段综合评价是目前亟待解决的问题.调制传递函数(MTF)是相机成像性能综合评价的关键指标,传统调制传递函数测量方法无法实现对Bayer滤波型彩色相机MTF全频段高精度测量.为了解决这个问题,本文提出了一种采用旋转刀口靶测量彩色相机调制传递函数的方法.理论方面,推导了Bayer滤波型彩色相机调制传递函数测量理论模型,仿真分析了刃函数采样率和刀口刃边倾斜角度误差对调制传递函数测量精度的影响,并给出了计算算法.实验方面,对彩色相机R,G,B三基色调制传递函数权重因子进行了实验定标,并搭建了基于条纹板和旋转刀口靶的彩色相机调制传递函数测量试验装置.采用旋转刀口靶法和条纹靶板法测量彩色相机MTF结果在耐奎斯特频率f_c处极差为0.061,在空间频率f_c/2处极差为0.043,试验结果验证了所提方法的有效性. 相似文献
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Akihiro Yamamoto Chih-Che Kuo Kei Sunouchi Satoshi Wada Ichirou Yamaguchi Hideo Tashiro 《Optical Review》2001,8(1):59-63
We developed a high speed and high resolution surface shape measurement system based on wavelength scanning interferometry with an electronically tuned Ti:sapphire laser. This laser emits pulses and the wavelength of each pulse can be tuned arbitrarily within 680 nm and 1056 nm. We also designed a high speed multiport CCD camera as a detector. This camera is synchronized with wavelength scanning of the laser at the frequency of 250 Hz. We could measure the object shape with a height resolution of 3.05 μm at the tuning range from 740.0 nm to 842.3 nm. By simple parabolic curve fitting to the Fourier peak of interference signals from each CCD pixel, the height resolution has been improved to the order of submicrometers. 相似文献
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介绍了一种有别于传统彩色航测相机的新型大面阵彩色CCD航测相机设计方案,该相机光学系统由Dalsa公司最新生产的6K×8K大面阵彩色CCD作为接收器.通过理论计算和ZEMAX光学设计软件的优化,给出了工作波长适应范围为0.46~0.70μm、焦距为360mm、视场角为10°、相对孔径为1∶4.3的设计实例.设计结果表明... 相似文献
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There has been a considerable effort made in several medical fields in the objective color analysis and characterization of biological tissues. Conventional colorimeters have proved inadequate for this purpose, since they do not provide spatial color information and because the measuring procedure randomly affects the color of the tissue. In this paper an imaging colorimeter is presented where the non imaging optical photodetector of the instrument is replaced with a charge-coupled device (CCD) sensor of a color video camera, enabling the independent capture of color information for any spatial point within its field of view. Combining imaging and colorimetry, the acquired image is calibrated and corrected under several ambient light conditions, providing non contact reproducible color measurements free of the errors and limitations present in conventional colorimeters. The technique has been used in hospital clinics for a wide variety of patients. These features highlight the potential of the imaging colorimeters as clinical and research tools for the standardization of clinical diagnosis and the objective evaluation of treatment efficacy. 相似文献
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将基于图像处理的自动检焦技术应用于线阵CCD推扫成像的空间遥感相机中。图像法检焦的关键在于对焦评价函数的选取。通常对焦评价函数是在摄影目标不变的情况下得出的,而推扫成像的线阵CCD相机在任意时刻所拍摄的景物都是不同的,这就给对焦评价函数的选取增加了难度。用功率谱的方法对任意景物在空间频域进行分析表明,功率谱对于自然景物具有一定的不变性。由此建立了基于功率谱的对焦评价函数,采用小波去噪与亮度归一化相结合的图像预处理技术有效地去除了图像噪声和亮度变化对对焦精度的影响。通过对功率谱评价函数进行加权处理,提高了对焦评价函数曲线的灵敏度。仿真实验表明了所构造的对焦评价函数是可行的。 相似文献
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非消声水池中低频换能器测量的空间域处理方法 总被引:1,自引:0,他引:1
提出了一种在非消声水池中低频换能器测量的空间域处理方法。该方法是在发射和接收换能器保持相对位置不变的情况下,通过多次无规则变换其在有限水域中的位置,让同频反射声的干扰贡献随机和无规则化,最终将上述所有位置接收的信号同步叠加而将同频反射声干扰消除,从而提取出了所需的直达波波形信号,克服了传统的脉冲测量技术受同频反射声干扰无法提取直达信号的问题。在5 m×7 m×6 m非消声水池,测量换能器样品,测量频率范围是400~2500 Hz,测量得到的结果与湖上测试结果相比,两者基本一致。该方法的实现,大大的提高了非消声水池的低频换能器测试能力,有效测量频率下限比一般脉冲测试方法降低一个数量级。 相似文献
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将激光信号与高帧频CCD结合,解决了光学系统中振动信号和激光信号之间的转换问题,不仅能够测量振动对系统光束指向稳定性的影响,而且能够得到振动信号本身的频率特性。利用该方法对振源为150 Hz和200 Hz两种条件下的光学系统受迫振动进行测量,得到了与输入信号相吻合的振动信号属性。通过实验与分析得知:时域振幅测量精度为6.25 m,频域分辨力为2 Hz,方法简便高效,测量结果准确,已应用于角多路准分子激光主振荡功率放大器系统打靶试验平台光束指向稳定性的研究中。 相似文献
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使用多个线阵CCD-计算机系统实时监控多界面位置 总被引:1,自引:0,他引:1
本文提出一套多界面位置实时监控系统。该系统采用八个线阵CCD像感器分别接收每个界面的光学图像。按照控制程序的设定,适时点亮界面的照明光源,同时驱动CCD开始工作,并在采集完界面位置信息后,关掉照明光源及CCD,以延长系统的寿命,实现长期连续工作。为了同时分别监控多个界面,设计了专用微机接口电路,通过硬件电路实现各界面数据的同时锁存,然后将每个CCD的光电信号采入计算机,解决了目视读数无法保证多处数据在时间上一致性的困扰。运用该系统监控多处油水界面,每处均可在100mL体积的检测管内测量到0.1mL的界面变化。 相似文献
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We present a method for multispectral imaging. This method uses color CCD cameras with a multiple-bandpass filter, which modifies the spectral response of the cameras used and enables concurrent acquisition of multiple images at defined spectral bands. We experimentally demonstrate methodological feasibility using two color CCD cameras and a polychroic mirror to simultaneously capture eight spectral bands. We discuss how the method developed is well suited for multispectral applications of transient phenomena or for real-time measurements. 相似文献
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轨道振动的非接触测量 总被引:4,自引:0,他引:4
CCD实时地非接触检测铁轨的振动情况是一种既方便又准确的测量方法。该方法能够测出轨道振动的幅度、频率、相位、加速度等参数。CCD非接触测振系统由照明光源、成像系统、CCD、检测逻辑接口电路及计算机软件构成。通过实际检测,它能够达到振幅测量精度为0.1mm,最大量程为100mm,频率不低于200Hz。该系统可扩展到用非接触方法测量各种机械振动、位移量和物体边沿检测等应用领域。 相似文献
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现有的水声管吸声系数测量的脉冲法,由于水声管高度的限制,存在低频限制。提出了基于"后置""逆滤波的宽带脉冲声测试方法,在测量获得系统的传递函数后,换能器发射宽频短脉冲信号,然后对接收到的标准反射体和待测样本的反射信号分别进行逆滤波处理,恢复未经传递系统"污染"的反射信号,计算待测样品的反射系数和吸声系数。仿真实验分析了"后置"逆滤波相对于传统"前置"逆滤波的在低频测试方面优势。对橡胶材料样品进行了实验测试,无论在低频段还是中高频段,宽带脉冲法和CW (Continuous Wave)脉冲法测试结果均吻合较好。宽带脉冲法是一种有效的测试方法,其低频测试能达到350 Hz,能有效拓展低频测试范围。 相似文献
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Qiang Wang Liying Tan Jing Ma Siyuan Yu Qiqi Han 《Journal of Russian Laser Research》2010,31(4):357-367
In satellite-to-ground laser communication links, the motion and vibration of the satellite are important factors that affect
the real-time requirements of pointing, acquiring, and tracking. In order to acquire again the beacon quickly and accurately
after losing it for a short time, we propose an improved method of detecting and processing for the beacon. In contrast to
the conventional design of processing systems for the beacon, the advantage of the system we designed is provided by the spatial
environment, where the optical communication terminal is located, and the motion trace of the beacon can be predicted effectively.
We perform numerical simulations and simulation experiments, with a sampling frequency of the CCD in a system of 60 Hz and
frequency and amplitude of the simulation vibration signal of 1 Hz and 0.1 mrad, respectively. We assume the motion of the
satellite to be of translation type. The prediction precision is not more than 6 pixels of the CCD after the algorithm converges
and the experimental results correspond fairly to the numerical simulation. 相似文献
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We demonstrate a new method of optical pulse generation in regeneratively mode-locked fiber ring lasers (RML-FRLs). The method is based on generating dominant longitudinal modes in the fiber ring cavity by means of a composite cavity structure and their intermode beating at the photodetector incorporated in the regenerative feedback loop. The beat signal is then used as a modulation signal to generate optical pulses in a regenerative mode-locking scheme, thereby eliminating the requirement for a high-Q rf bandpass filter in a conventional RML-FRL. Optical pulses with a repetition frequency of 3.6 GHz have been generated successfully with a supermode noise suppression of more than 48 dB and a low phase noise of -85 dBc/Hz at 10 kHz offset from the carrier frequency. 相似文献
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基于光学相关的空间相机像移测量方法研究 总被引:1,自引:0,他引:1
为了测量由卫星姿态不稳定或振动等原因引起的空间相机的亚像元像移,使用了光学联合变换相关的方法对安装在相机焦面上的辅助面阵CCD采集到的相邻两帧图像进行相关运算.给出了使用该方法测量像移的原理,提出对联合变换相关器的输入面采用拉普拉斯卷积核进行边缘锐化,对功率谱相减并以0值进行二值化的处理方法提高像移测量准确度,并使用该方法对不同信噪比下的不同景物进行了像移测量仿真.结果表明:对于信噪比SNR=1的输入图像,当像移范围在 0~55个像元内时,该方法的像移测量误差小于0.2个像元. 相似文献