High-resolution Scanning System Research Articles

Affordable and customizable high-resolution scanning system for measurement of acoustic fields

Spatial scans of acoustic fields are often required to characterize acoustic system behavior. Automated positioning systems allow for higher spatial resolution, more efficient use of time, and increased repeatability and precision during data collection than is possible manually. Unfortunately, commercial systems can be expensive, difficult to customize after purchase, and can be very cumbersome to manipulate. The present work describes an affordable and customizable scanning system that can be operated through MATLAB using an Arduino microcontroller and constructed with OpenBuilds hardware. We will outline the integration of an oscilloscope and function generator with the motion control system to enable a completely automated measurement system. Further, we will discuss potential pitfalls one may encounter when creating a similar system and highlight best practices that allow you to avoid those problems at the system design stage. This work will discuss similar systems created to characterize underwater acoustic metamaterials (doi:10.1121/10.0009161), quantify performance of an additively manufactured acoustic diffuser (doi:10.1121/1.5147148), define pressure field responses due to inclusion of an acoustic metasurface used for acoustic holography (doi:10.26153/tsw/13999), and analyze acoustic properties of cylindrical sediment samples containing infauna (doi:10.1121/2.0000744). [Work sponsored by ARLUT, ONR, Sandia, and Samsung.]

Design of High Resolution Magnetic Probe for Magnetic Field Measurement on AES Cryptographic FPGA to Analyze the Side Channel Attack

In this paper, a high resolution magnetic measurements are performed in an AES (advanced encryption standard) cryptographic FPGA by using a newly designed magnetic probe. The probe consists of high resolution scanning system and magnetic field collecting coil integrated with 3-stage low noise amplifier to enhance the sensed voltage. Also, to improve the performance of the magnetic coil, the Si-substrate is removed under the coil by using FIB process. The results and discussion section clearly shows that, the proposed magnetic probe gives more detailed information about the susceptible area of an AES cryptographic FPGA surface with high resolution maps in different frequency bands compared with the existing magnetic probe.

Local Scour around a Model Hydrokinetic Turbine in an Erodible Channel

Laboratory experiments were performed to study the effect of an axial-flow hydrokinetic turbine model on an erodible channel under both clear water and live-bed conditions. Clear water experiments were performed at two scales with a local bed shear stress just below the critical state. Live-bed experiments, performed at small scale, examined the interactions between relatively large-scale bedforms and the flow induced by an axial flow turbine. Spatiotemporal topographic measurements were obtained by sonar and by a state-of-the-art high-resolution scanning system integrated into an automated data acquisition carriage designed and fabricated at the St. Anthony Falls Laboratory at the Univ. of Minnesota. Results indicate that the presence of the turbine rotor increases the local shear stress resulting in accelerated and expanded scour development when compared with typical bridge pier scour mechanisms. The inferred key difference is the alteration of the flow patterns in the rotor wake leading to an accelerated flow region below the bottom tip. The footprint of the rotor is observed in the extension and scaling of the bed surface area impacted by the turbine and consistent with the near-wake region. Temporally averaged bed topography data from live-bed experiments indicate amplified scour depths in the turbine near-wake region as compared with the clear water results despite spatial patterns remaining qualitatively similar.

Detection and Removal of Short-circuits on GEM-foils

Abstract High resolution scanning system was used to locate the areas on GEM-foils that might contain short-circuit. These areas were analyzed by threshold method for fast identification. Different methods to remove short-circuits on GEM-foils were studied. Since using the standard procedure of “burning” shorts with high current might incur additional damage to the foil, we have also studied several non-destructive methods. These methods were for example washing with high power ultrasonic, manual extirpation and by using resonance frequencies. We will show results on locating and removing the GEM-shorts from standard bi-conical 10 cm ¥ 10 cm foils.

Analysis of sound propagation in an experimental model using a high resolution scanning system

The aim of this work is to analyze low frequency and mid frequency sound propagation in a coupled volume system for different aperture configurations. The cross sectional areas of the primary room and the secondary room are scanned over high spatial resolution grids using an automated scanning system. This procedure is carried out systematically for different aperture configurations. A dedicated analysis algorithm converts experimentally measured room impulse response data at each grid point into energy distributions and instantaneous sound pressure levels as a function of time. The analysis algorithm provides streams of data for a selected frequency thereby creating an animation of sound propagating through the coupled volume system. This work will demonstrate wave phenomena for different aperture configurations at low frequencies and mid frequencies by using animations to analyze the experimentally measured data.

The Impact of Acoustic Velocity Variations on Target Detectability in Ultrasonic Images of the Breast

Experimentally obtained ultrasonic phase aberration profiles in the breast were used to investigate the impact of acoustic velocity variations on images of simulated breast lesions. The imaging properties of several phased-array transducers with varying frequencies and geometries were studied as phase error profiles of increasing magnitude were introduced. The targets studied were anechoic lesions of various sizes. The results indicate that phase aberrations significantly degrade the contrast of ultrasonic breast images, especially for high-resolution scanning systems.

Prospective Evaluation of Radial Keratotomy: Photokeratoscope Corneal Topography

Preoperative and postoperative corneascope photographs of 368 myopic patients undergoing radial keratotomy in the Prospective Evaluation of Radial Keratotomy (PERK) study were optically scanned and digitized. A highresolution scanning system was developed in order to quantify the preoperative and postoperative corneal shape accurately. Careful analysis of the 72 data points in the nine representative rings demonstrated that corneal topography is best represented by radius of curvature from the center to the periphery. The normal myopic cornea flattens approximately +0.28 mm from the center to the periphery, demonstrating the cornea's aspheric nature. More highly myopic patients in the PERK population (−4.50 to −8.00 diopters [D]) demonstrated corneas that are 0.08 to 0.10 mm steeper than the less myopic population (−2.00 to −3.12 D). Optical zone, patient age, and gender are all correlated to changes in corneal topography after radial keratotomy. In more myopic populations, men have corneas which are flatter than those of women by 0.09 to 0.11 mm in all rings represented on corneoscopy. Highly myopic males also experience more corneal flattening after 3.0-mm optical zone radial keratotomy. Regardless of the optical zone used in radial keratotomy, the resulting corneal topography flattens in all rings. However, the ratio of millimeters of radius of curvature change to diopters of correction is consistent for each ring. The dioptric change observed after radial keratotomy corresponds closely with the millimeters of flattening at the respective rings being examined. The central rings flatten 0.166-mm radius of curvature per diopter of refractive alteration obtained. The largest degree of corneal flattening occurs centrally, 0.72 mm, in the more highly myopic patients who underwent 3-mm optical zone radial keratotomy. The use of smaller optical zones in radial keratotomy produces larger changes in the radius of curvature and, consequently, in the amount of refraction than when larger optical zones are used. When compared with younger patients, older patients with 3.0, 3.5, and 4.0 optical zone radial keratotomies experience more central and peripheral corneal flattening. This study of the corneal topography of the myopic population demonstrates that the refractive change resulting from radial keratotomy is related to alterations in corneal topography. The use of similar modifications of the corneal surface may be effective for newer refractive surgical procedures.

Medical diagnostics: Visual/aural techniques: High-resolution scanning systems, a retinal camera, and a cardiac-output earpiece show promise

Describes some Japanese developments in medical diagnostic aids including high-resolution scanning systems, a retinal camera, and a cardiac-output earpiece.

The bright-display electron gun, a high-resolution scanning system

The Large-Area Electronic Display equipment developed for the U. S. Army Electronics Research and Development Laboratory by the Electronics Laboratory of the General Electric Company had design objectives that required the development of a high-performance electron-beam scanning system. The recording sensitivity of the thermoplastic tape, coupled with the 20 megahertz maximum signal-frequency, required a high beam-current-density, 4 kv, electron beam. Electron-optical focus-aberrations and deflection-distortions are key factors of this 3000-line raster-scan system. An aberration balance condition is used to remove deflection-distortions. To achieve a satisfactory recording-sensitivity over the entire 50 mm-square writing-format, it is necessary to maintain a uniform spot-shape no greater than two-thirds the 16µ line-to-line spacing.