Optical alignment technique of 3D geometric camera system for 3D imaging

2010 ◽  
Author(s):  
Sabri Gurbuz ◽  
Sumio Yano
Keyword(s):  
3D Imaging ◽  
Camera System ◽  
Alignment Technique ◽  
Optical Alignment

Innovative optical alignment technique for CMP wafers

2002 ◽  
Author(s):  
Ayako Sugaya ◽  
Yuho Kanaya ◽  
Shinichi Nakajima ◽  
Tadashi Nagayama ◽  
Naomasa Shiraishi
Keyword(s):  
Alignment Technique ◽  
Optical Alignment

Efficient Optical Alignment Technique for Compact 100 and 400 GbE TOSAs With Integrated Multiplexing With Free Space Optics

2019 ◽  
Vol 37 (3) ◽  
pp. 799-807 ◽  
Author(s):  
Tadashi Murao ◽  
Keita Mochizuki ◽  
Kazutaka Ikeda ◽  
Mizuki Shirao ◽  
Kiyotomo Hasegawa ◽  
...  
Keyword(s):  
Free Space ◽  
Free Space Optics ◽  
Space Optics ◽  
Alignment Technique ◽  
Optical Alignment

A Passive Optical Alignment Technique for Single-mode Fibers and Light-source Arrays

2017 ◽  
Author(s):  
K. Adachi ◽  
A. Nakanishi ◽  
T. Suzuki ◽  
H. Irie ◽  
Y. Sasaki ◽  
...  
Keyword(s):  
Light Source ◽  
Single Mode ◽  
Alignment Technique ◽  
Optical Alignment

scholarly journals In-Situ Evaluation of the Pitch of a Reflective-Type Scale Grating by Using a Mode-Locked Femtosecond Laser

2021 ◽  
Vol 11 (17) ◽  
pp. 8028
Author(s):  
Dong Wook Shin ◽  
Lue Quan ◽  
Yuki Shimizu ◽  
Hiraku Matsukuma ◽  
Yindi Cai ◽  
...  
Keyword(s):  
Frequency Comb ◽  
Optical Frequency Comb ◽  
Optical Frequency ◽  
Optical Components ◽  
Uncertainty In Measurement ◽  
Fabry Perot ◽  
Alignment Technique ◽  
Optical Alignment ◽  
Expression Of Uncertainty

Major modifications are made to the setup and signal processing of the method of in-situ measurement of the pitch of a diffraction grating based on the angles of diffraction of the diffracted optical frequency comb laser emanated from the grating. In the method, the improvement of the uncertainty of in-situ pitch measurement can be expected since every mode in the diffracted optical frequency comb laser can be utilized. Instead of employing a Fabry-Pérot etalon for the separation of the neighboring modes in the group of the diffracted laser beams, the weight-of-mass method is introduced in the method to detect the light wavelength in the Littrow configuration. An attempt is also made to reduce the influence of the non-uniform spectrum of the optical comb laser employed in the setup through normalization operation. In addition, an optical alignment technique with the employment of a retroreflector is introduced for the precise alignment of optical components in the setup. Furthermore, a mathematical model of the pitch measurement by the proposed method is established, and theoretical analysis on the uncertainty of pitch measurement is carried out based on the guide to the expression of uncertainty in measurement (GUM).

Design and calibration of an IVEM for general 3-dimensional imaging of non-diffracting materials

1992 ◽  
Vol 50 (2) ◽  
pp. 1040-1041
Author(s):  
Neil Rowlands ◽  
Jeff Price ◽  
Michael Kersker ◽  
Seichi Suzuki ◽  
Steve Young ◽  
...  
Keyword(s):  
3D Imaging ◽  
Tomographic Reconstruction ◽  
Three Dimensional ◽  
3 Dimensional ◽  
3D Microstructure ◽  
Image Translation ◽  
Digital Correlation ◽  
On Line ◽  
Mechanical Stage ◽  
Projection Angle

Three-dimensional (3D) microstructure visualization on the electron microscope requires that the sample be tilted to different positions to collect a series of projections. This tilting should be performed rapidly for on-line stereo viewing and precisely for off-line tomographic reconstruction. Usually a projection series is collected using mechanical stage tilt alone. The stereo pairs must be viewed off-line and the 60 to 120 tomographic projections must be aligned with fiduciary markers or digital correlation methods. The delay in viewing stereo pairs and the alignment problems in tomographic reconstruction could be eliminated or improved by tilting the beam if such tilt could be accomplished without image translation.A microscope capable of beam tilt with simultaneous image shift to eliminate tilt-induced translation has been investigated for 3D imaging of thick (1 μm) biologic specimens. By tilting the beam above and through the specimen and bringing it back below the specimen, a brightfield image with a projection angle corresponding to the beam tilt angle can be recorded (Fig. 1a).

Precise on-line Measurement of Lattice Vectors

1990 ◽  
Vol 48 (1) ◽  
pp. 530-531
Author(s):  
W.J. de Ruijter ◽  
Sharma Renu
Keyword(s):  
Electron Microscope ◽  
Measurement Errors ◽  
Dynamic Range ◽  
Structural Information ◽  
Statistical Parameter ◽  
Systematic Errors ◽  
Geometric Distortion ◽  
Crystal Silicon ◽  
Camera System ◽  
On Line

Established methods for measurement of lattice spacings and angles of crystalline materials include x-ray diffraction, microdiffraction and HREM imaging. Structural information from HREM images is normally obtained off-line with the traveling table microscope or by the optical diffractogram technique. We present a new method for precise measurement of lattice vectors from HREM images using an on-line computer connected to the electron microscope. It has already been established that an image of crystalline material can be represented by a finite number of sinusoids. The amplitude and the phase of these sinusoids are affected by the microscope transfer characteristics, which are strongly influenced by the settings of defocus, astigmatism and beam alignment. However, the frequency of each sinusoid is solely a function of overall magnification and periodicities present in the specimen. After proper calibration of the overall magnification, lattice vectors can be measured unambiguously from HREM images.Measurement of lattice vectors is a statistical parameter estimation problem which is similar to amplitude, phase and frequency estimation of sinusoids in 1-dimensional signals as encountered, for example, in radar, sonar and telecommunications. It is important to properly model the observations, the systematic errors and the non-systematic errors. The observations are modelled as a sum of (2-dimensional) sinusoids. In the present study the components of the frequency vector of the sinusoids are the only parameters of interest. Non-systematic errors in recorded electron images are described as white Gaussian noise. The most important systematic error is geometric distortion. Lattice vectors are measured using a two step procedure. First a coarse search is obtained using a Fast Fourier Transform on an image section of interest. Prior to Fourier transformation the image section is multiplied with a window, which gradually falls off to zero at the edges. The user indicates interactively the periodicities of interest by selecting spots in the digital diffractogram. A fine search for each selected frequency is implemented using a bilinear interpolation, which is dependent on the window function. It is possible to refine the estimation even further using a non-linear least squares estimation. The first two steps provide the proper starting values for the numerical minimization (e.g. Gauss-Newton). This third step increases the precision with 30% to the highest theoretically attainable (Cramer and Rao Lower Bound). In the present studies we use a Gatan 622 TV camera attached to the JEM 4000EX electron microscope. Image analysis is implemented on a Micro VAX II computer equipped with a powerful array processor and real time image processing hardware. The typical precision, as defined by the standard deviation of the distribution of measurement errors, is found to be <0.003Å measured on single crystal silicon and <0.02Å measured on small (10-30Å) specimen areas. These values are ×10 times larger than predicted by theory. Furthermore, the measured precision is observed to be independent on signal-to-noise ratio (determined by the number of averaged TV frames). Obviously, the precision is restricted by geometric distortion mainly caused by the TV camera. For this reason, we are replacing the Gatan 622 TV camera with a modern high-grade CCD-based camera system. Such a system not only has negligible geometric distortion, but also high dynamic range (>10,000) and high resolution (1024x1024 pixels). The geometric distortion of the projector lenses can be measured, and corrected through re-sampling of the digitized image.

Human Factors Evaluation of 360 Panoramic View Camera System for Ground Vehicle

2007 ◽  
Author(s):  
Cheng Li Wei ◽  
Ang Cher Wee ◽  
Chan Wai Herng ◽  
Ying Meng Fai
Keyword(s):  
Human Factors ◽  
Panoramic View ◽  
Camera System ◽  
Ground Vehicle
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