Flatness Measurement Research Articles

21305 擬似平面を用いたモンテカルロ法による平面度の不確かさ評価法(OS13 計測・試験における不確かさ評価と応用(1),オーガナイズドセッション)

This paper describes an evaluation method of the measurement uncertainty of the reference flat as component part in the fizeau-type flatness measurement machine. In order to evaluate of uncertainty of the reference flat, the Monte Carlo simulation was applied to estimate the distribution of the peak-to-valley (PV) value +with pseudo flats as the test flat and the measurement result. As the result of evaluation by simulation, it has been clarified that the uncertainty of the reference flat is affected by the uncertainty of the test flat and the interferometer of the flatness measurement machine.

Voice Activity Detection Based on Discriminative Weight Training Incorporating a Spectral Flatness Measure

In this paper, we present an approach to incorporate discriminative weight training into a statistical model-based voice activity detection (VAD) method. In our approach, the VAD decision rule is derived from the optimally weighted likelihood ratios (LRs) using a minimum classification error (MCE) method. An adaptive on-line means of selecting two kinds of weights based on a power spectral flatness measure (PSFM) is devised for performance improvement. The proposed approach is compared to conventional schemes under various noise conditions, and shows better performance.

Volume of the set of unistochastic matrices of order 3 and the mean Jarlskog invariant

A bistochastic matrix B of size N is called unistochastic if there exists a unitary U such that Bij=|Uij|2 for i,j=1,…,N. The set U3 of all unistochastic matrices of order N=3 forms a proper subset of the Birkhoff polytope, which contains all bistochastic (doubly stochastic) matrices. We compute the volume of the set U3 with respect to the flat (Lebesgue) measure and analytically evaluate the mean entropy of an unistochastic matrix of this order. We also analyze the Jarlskog invariant J, defined for any unitary matrix of order three, and derive its probability distribution for the ensemble of matrices distributed with respect to the Haar measure on U(3) and for the ensemble which generates the flat measure on the set of unistochastic matrices. For both measures the probability of finding |J| smaller than the value observed for the Cabbibo–Kobayashi–Maskawa matrix, which describes the violation of the CP parity, is shown to be small. Similar statistical reasoning may also be applied to the Maki–Nakagawa–Sakata matrix, which plays role in describing the neutrino oscillations. Some conjectures are made concerning analogous probability measures in the space of unitary matrices in higher dimensions.

Experimental Determination of the Effect of the Surface Curvature on Rolling Resistance Measurements

Abstract REFERENCE: Freudenmann, T., Unrau, H.-J., and El-Haji, M., "Experimental Determination of the Effect of the Surface Curvature on Rolling Resistance Measurements," Tire Science and Technology, TSTCA, Vol. 37, No. 4, October - December 2009, pp. 254-278. Vehicle and tire manufacturers usually perform rolling resistance measurements on external drums with diameters of 1.71 or 2.0 m. The rolling resistance measured on these test benches is higher than the actual rolling resistance measured on a flat surface. This deviation is caused by the drums’ curvature. In 1979, S. K. Clark aimed to solve this problem by developing a formula, which converts the rolling resistance of a tire measured on a curved surface into the corresponding rolling resistance on a plane. This formula is still used today in ISO and SAE standards. To verify Clark’s universally accepted formula, a research project was initiated at the Universität Karlsruhe. A combined test bench that allows measurements on two external drums of different diameter and a continuous flat track with the same wheel suspension was built up and came into operation. The rolling resistances of six different tires on the three surfaces were measured under variation in operational parameters, such as tire load and inflation pressure. Comparison of converted values from measurements on external drums with flat track measurements showed the necessity for an upgrade of the existing formula. By conducting a multiple regression analysis, which took various tire properties and operational parameters into account, a modified formula was derived. Application of this new formula on the measurement data of the six tires as well as on further measurements showed excellent results.

Comparison of 2D and 3D Views for Evaluation of Flat Lesions in CT Colonography

Flat lesions in the colon may result in false-negative computed tomography colonography interpretations. It is unknown whether flat lesions are better measured on two-dimensional (2D) or three-dimensional (3D) images and which settings are optimal for enhanced reproducibility and decreased variability. We evaluated these factors to determine whether 2D or 3D is best for flat lesion measurements. Eighty-eight lesions in 66 patients from a previously published clinical trial were analyzed. Lesions were viewed with four methods including 2D at three window/level settings and 3D endoluminal view. Lesions in either supine or prone were counted as one dataset. Long axis and height were measured. Criteria of "height" (<or=3 mm high) or "ratio" (height <or=half the long axis) were applied. A subset of lesions was subject to inter- and intra-observer variability analysis. With the "height" criterion, more datasets were classified as flat in 2D flat (n = 76), 2D soft tissue (n = 82), and 3D (n = 73) views than in the 2D lung (n = 49) view. If long axis is used as the key metric, endoluminal 3D (12.1%) views significantly showed the least inter-observer variability compared to lung (18.9%) or soft tissue (20.2%) views. Intra-observer variability was low overall for all methods. When characterizing lesions as flat, a consistent viewing method should be used. To minimize inter-observer variability (such as when following a patient over time), it is best to use the ratio criterion for flat lesion definition incorporating the single longest dimension on 3D views as the key metric.

Traceability enhancement in angle measurements

Traceability of angle measurements is based mainly on the standard of the plane angle – prism (polygon) calibrated at appropriate accuracy. Nevertheless, the standard (etalon) of flat angle – polygon has many restrictions for the transfer of angle unit – radian (rad) and other units of angle. It depends on number of angles formed by the flat sides of the polygon. Here is proposed a possibility to create the standard of the plane angle equal to π rad using the circular scale with the rotation axis of very high accuracy and two opposite placed precision reading instruments with appropriate alignment. Proposed method permits an implementation of π rad as primary standard angle and enables to assure a traceability of flat angle measurements at laboratory environment. Short information about the multipurpose angle measurement test bench developed is presented.

A Climatology of Nocturnal Low-Level Jets at Cabauw

Abstract A climatology of nocturnal low-level jets (LLJs) is presented for the topographically flat measurement site at Cabauw, the Netherlands. LLJ characteristics are derived from a 7-yr half-hourly database of wind speed profiles, obtained from the 200-m mast and a wind profiler. Many LLJs at Cabauw originate from an inertial oscillation, which develops after sunset in a layer decoupled from the surface by stable stratification. The data are classified to different types of stable boundary layers by using the geostrophic wind speed and the isothermal net radiative cooling as classification parameters. For each of these classes, LLJ characteristics like frequency of occurrence, height above ground level, and the turning of the wind vector across the boundary layer are determined. It is found that LLJs occur in about 20% of the nights, are typically situated at 140–260 m above ground level, and have a speed of 6–10 m s−1. Development of a substantial LLJ is most likely to occur for moderate geostrophic forcing and a high radiative cooling. A comparison with the 40-yr ECMWF Re-Analysis (ERA-40) is added to illustrate how the results can be used to evaluate the performance of atmospheric models.

Path integral regularization of pure Yang-Mills theory

In enlarging the field content of pure Yang-Mills theory to a cutoff dependent matrix valued complex scalar field, we construct a vectorial operator, which is by definition invariant with respect to the gauge transformation of the Yang-Mills field and with respect to a Stueckelberg type gauge transformation of the scalar field. This invariant operator converges to the original Yang-Mills field as the cutoff goes to infinity. With the help of cutoff functions, we construct with this invariant a regularized action for the pure Yang-Mills theory. In order to be able to define both the gauge and scalar fields kinetic terms, other invariant terms are added to the action. Since the scalar fields flat measure is invariant under the Stueckelberg type gauge transformation, we obtain a regularized gauge-invariant path integral for pure Yang-Mills theory that is mathematically well defined. Moreover, the regularized Ward-Takahashi identities describing the dynamics of the gauge fields are exactly the same as the formal Ward-Takahashi identities of the unregularized theory.

In Situ Chip Stress Extractions for LFBGA Packages Through Piezoresistive Sensors

Piezoresistive sensors have been demonstrated to be an accurate and efficient tool for stress measurements on chip surfaces inside microelectronic packaging. In this work, test chips with piezoresistive stress sensors, diode temperature sensors as well as heaters were first designed, fabricated, and calibrated. We next packaged the test chips into low profile, fine pitch ball grid array (LFBGA) packaging with 196 balls and measured the stresses on chip surfaces inside the packaging. After measuring the packaging induced stress as well as the stress under stable environmental temperature rises, it was found that compressive stresses were obtained at room temperature, and the stresses were relaxed as temperature went up at a rate between 0.45 MPa/°C and 0.60 MPa/°C. For thermo-stress experiments, the temperatures on chip surfaces at different power levels were measured, and compressive chip stresses were first extracted. As the chip power increased, the compressive stresses became tensions. Since the LFBGA structure is thinner with higher packaging efficiency, different results from our earlier plastic quad flat package stress measurements were observed and discussed. In addition, the final comparisons between the experimental data and the finite element simulations show good consistency.

Some properties of angular integrals

We find new representations for Itzykson–Zuber like angular integrals for arbitrary β, in particular for the orthogonal group O(n), the unitary group U(n) and the symplectic group Sp(2n). We rewrite the Haar measure integral, as a flat Lebesge measure integral, and we deduce some recursion formulae on n. The same methods give also Shatashvili's type moments. Finally, we prove that, in agreement with Brezin and Hikami's observation, the angular integrals are linear combinations of exponentials whose coefficients are polynomials in the reduced variables (xi − xj)(yi − yj).

SU‐FF‐T‐391: IC Profiler Study: The End of Water Tank Measurements for Monthly QA?

Purpose: To investigate the possibility of using the IC Profiler (Sun Nuclear Corporation) for monthly QA of linear accelerators. Method and Materials: Photon and electron profiles measured with the IC Profiler, consisting of 251 ionization chambers located along the X, Y and diagonal axes, were compared to the profiles measured in water with an IC10 ionisation chamber. Three different methods were used for energy measurement of the photon and electron beams: 1) different thicknesses of solid water slab on the IC Profiler, 2) an acrylic continuous energy wedge and 3) a step wedge made of solid water. For the last two methods, the measured PDD equivalent curve was corrected for the change in profiles in order to remove the profile effect. All photon measurements were performed at SSD=75 cm with a 30×30 cm2 field size in order to be equivalent to a 40×40 cm2 at the isocenter. The electron measurements were done at SSD=100 cm with a 25×25 cm2 field size. Results: The agreement between symmetry and flatness measurements with the IC Profiler and the water tank was very good: maximum relative difference of −0.7% for 6 MV and 25 MV photon beams and −1.3% for electron beams (from 4 MeV to 22 MeV). Energy measurement using methods 2 and 3 was very fast and seemed to be as sensitive to an energy change as method 1. Method 2 gives a linear interpolation of the relative dose as function of the depth whereas method 3 gives the relative dose averaged over 10 detectors at 4 different depths. Conclusion: The IC Profiler is well adapted to the measurement of photon and electron profiles. Three different methods were tested for energy determination and more measurements are needed to establish the most accurate one.

SU‐FF‐T‐316: 3 Years of Data Collection and Analysis of Film Flatness and Symmetry Using Vidar/ RIT Software From Different Centers Nation Wide

Purpose: To analyze accuracy and dependability of RIT software / Vidar Scanner in film flatness and symmetry measurement nationwide. Method and Materials: EDR and V films were exposed to 200 MU 6X &amp; 15X radiations at depth of 10cm in solid water phantom, 100cmSSD with filed size of 20×20cm. Measurements were repeated with different phantom orientation, phantom of different vendors, and different packs of films, different processor, and different linac machines. Water beam scanning was done with PTW water tank at the lowest speed, central axis and at steps of 3cm off axis. Profiles were analyzed using Memphysto software. Exposed films were scanned at different 90' intervals and flipped in each orientation for comparison. Measurements were repeated at different centers with different linac and different RIT software and Vidar Scanner Results: RIT's film flatness scanning shows an area of increased intensity on the left hand side of the scan regardless of using different Linac machine, Vidar scanner or the orientation of the phantom being used. No mirror images were obtained in RIT when the flatness film was scanned flipped or if rotated at different angles. Results of ‘Scan info’ test performed weekly on Vidar scanner for three months showed no failure and passed the overall performance and water beam scanning profile collected by PTW showed persistent uniform symmetry and flatness using TG‐45 guidelines. Conclusions: None of the mentioned effects were seen while scanning a patient's QA film. Only in scanning of flatness film, one would notice the above effects. RIT believes that a systemic scanner bias (within Vidar production specifications) may be causing this effect and is working on methods to compensate for any systemic scanner bias.

Improved Emotion Recognition With a Novel Speaker-Independent Feature

Emotion recognition is one of the latest challenges in human-robot interaction. This paper describes the realization of emotional interaction for a Thinking Robot, focusing on speech emotion recognition. In general, speaker-independent systems show a lower accuracy rate compared with speaker-dependent systems, as emotional feature values depend on the speaker and their gender. However, speaker-independent systems are required for commercial applications. In this paper, a novel speaker-independent feature, the ratio of a spectral flatness measure to a spectral center (RSS), with a small variation in speakers when constructing a speaker-independent system is proposed. Gender and emotion are hierarchically classified by using the proposed feature (RSS), pitch, energy, and the mel frequency cepstral coefficients. An average recognition rate of 57.2% (plusmn 5.7%) at a 90% confidence interval is achieved with the proposed system in the speaker-independent mode.

Method for absolute flatness measurement of optical surfaces

To determine the absolute flatness deviations of optical surfaces, a novel method using two optical plates to achieve the absolute flatness test is presented. Absolute deviations of three surfaces, the rear surface of plate I and the front and rear surfaces of plate II, are obtained by four measurements. Wavefront error due to the inhomogeneity of plate II is measured beforehand and is then subtracted from the test results. Vertical profiles of the three surfaces are compared with the measurement results obtained by Zygo's three-flat application. Good agreement validates our method. The advantage of our method is that only one transmission flat is needed during the absolute test, which is especially useful for large-aperture interferometer calibration.

Measurement-based Driving Dynamics Simulation

The properties of the axles and tyres play a key role in the simulation of driving dynamics. In most cases, the axles are represented as multi-body systems. In the measurement-based driving dynamics model that is used in passenger car chassis development at Volkswagen, the axles and tyres are described completely by measured data. The axle data are gained from measurements taken on the Kinematics-and-Compliance (K-and-C) test rig, while the tyre data are from flat track measurements.

15% root-mean-square flat-intensity laser beam formed using a binary-amplitude spatial light modulator

We demonstrate a digital micromirror device (DMD)-based optical system that converts a spatially noisy quasi-Gaussian to an eighth-order super-Lorentzian flat-top beam. We use an error-diffusion algorithm to design the binary pattern for the Texas Instruments DLP device. Following the DMD, a telescope with a pinhole low-pass filters the beam and scales it to the desired sized image. Experimental measurements show a 1% root-mean-square (RMS) flatness over a diameter of 0.28 mm in the center of the flat-top beam and better than 1.5% RMS flatness over its entire 1.43 mm diameter. The power conversion efficiency is 37%. We develop an alignment technique to ensure that the DMD pattern is correctly positioned on the incident beam. An interferometric measurement of the DMD surface flatness shows that phase uniformity is maintained in the output beam. Our approach is highly flexible and is able to produce not only flat-top beams with different parameters, but also any slowly varying target beam shape. It can be used to generate the homogeneous optical lattice required for Bose-Einstein condensate cold atom experiments.

A semi-open-loop coding mode selection algorithm based on EFM and selected AMR-WB+ features

To solve the problems of the AMR-WB+ (Extended Adaptive Multi-Rate-WideBand) semi-open-loop coding mode selection algorithm, features for ACELP (Algebraic Code Excited Linear Prediction) and TCX (Transform Coded eXcitation) classification are investigated. 11 classifying features in the AMR-WB+ codec are selected and 2 novel classifying features, i.e., EFM (Energy Flatness Measurement) and stdEFM (standard deviation of EFM), are proposed. Consequently, a novel semi-open-loop mode selection algorithm based on EFM and selected AMR-WB+ features is proposed. The results of classifying test and listening test show that the performance of the novel algorithm is much better than that of the AMR-WB+ semi-open-loop coding mode selection algorithm.

502 大口径薄片SiウエハのOn-Machine 3D形状計測システムの開発(第2報)(OS8-(1) 精密微細加工と評価,オーガナイズドセッション)

The miniaturization and integration of IC chips are increasingly demanded by mobile devices. Ever thinner and flatter Si wafers are required for the applications like IC card, mobile phone and digital music player in addition to larger size. The measurement and evaluation of wafer flatness and thickness therefore became important. To solve the conventional measurement problem in the first report, we used multi probes to develop a new metrology system for one-side and on-machine measuring. In the second report, we compared the measurement results by changing scan method from concentric to spiral and discussed the difference in sampling scheme.

The method for multi-beam laser heterodyne high-precision measurement of the glass thickness

Multi-beam laser heterodyne measurement of glass thiclcness is based on laser heterodyne measurement technology and laser Doppler technology. We deduced the harmonic expression of photodetector output current, discussed the feasibility and theory of the method which make use of the non-contact multi-beam laser heterodyne to increase the precision of the glass thickness measurement, and made simulation in different situation with Matlab. The results showed that the maximum error is 0.3% at different incidence angles in flat glass thickness measurement, which has an obvious advantage in accuracy over the other methods.

A New Noncontact Flatness Measuring System of Large 2-D Flat Workpiece

The flatness measurement of a large 2D flat workpiece such as a satellite solar panel substrate is a key problem in its manufacturing process. Based on the current measuring methods and the actual engineering project, a new noncontact high-precision, low-cost large 2-D flat workpiece flatness measuring system is developed, in which the techniques of oblique optical triangle measuring structure, virtual measurement datum plane, and error self-correction are adopted. By means of the oblique optical triangle measuring structure that is first proposed, the measuring area and resolution of the measuring system can be greatly increased. Meanwhile, on the basis of the techniques of virtual measurement datum plane and error self-correction, the noncontact high-precision, low-cost flatness measurement can be realized on a nonprecise large metallic platform. Experimental results on the satellite solar panel substrate indicate the correctness and effectiveness of the proposed noncontact flatness-measuring system of the large 2-D flat workpiece. Although the specific application of the satellite solar panel substrate is presented in this paper, the proposed measurement techniques and measuring system could be applied independent of the nature or use of the large 2-D flat workpieces.