Stephen A Cerwin

6463202, Oct 8, 2002

Jun 9, 2000

09/591084

Stephen A. Cerwin - San Antonio TX
David B. Chang - Tustin CA

Southwest Research Institute - San Antonio TX

G02B 610

385124, 385127

A waveguide designed to minimize bend-induced losses. The waveguide has three regions of varying indices of refraction. The indices of refraction are chosen so that the field is a trigonometric function in the core region, evanescent in the intermediate region, and trigonometric again in the outer region. The widths of each region are calculated to further reduce losses.

6495819, Dec 17, 2002

Aug 8, 2000

09/634553

Stephen A. Cerwin - San Antonio TX
David B. Chang - Tustin CA

Southwest Research Institute - San Antonio TX

G01J 400

25022719, 25022727, 356 355

A method of two interferometric configurations to measure bending of an extended element. The measurement arm of each configuration is a long optical fiber. A first interferometric configuration has a segment of its measurement arm attached to one side of the element. The second interferometric configuration has a segment of its measurement arm attached to one side of the element and another segment of its measurement arm attached to an opposing side of the element. The two configurations are used to obtain two sets of interference fringe measurement values. If one set is subtracted from the other, the result is intensity differential values that indicate only the effects of bending and not of temperature or pressure. Variations of the method can be used for irregularly shaped elements.

6656135, Dec 2, 2003

Feb 20, 2001

09/789832

Susan W. Zogbi - San Antonio TX
Larry D. Canady - San Antonio TX
Jerome A. Helffrich - San Antonio TX
Stephen A. Cerwin - Pittsboro NC
Kevin S. Honeyager - San Antonio TX
Armando de los Santos - San Antonio TX
Christopher B. Catterson - San Antonio TX

Southwest Research Institute - San Antonio TX

A61B 5103

600594, 600587, 600595, 128897, 32420711

A system that remotely measures displacement between two objects. A passive sensor is affixed between the objects. The internal sensor uses magnetic coupling between two sensor elements to measure their relative displacement. The sensors are either a) a permeable rod and a complimentary coil in parallel with a tuning capacitor; or b) two permeable rods, each having its own surrounding coil and a tuning capacitor. One of the sensor elements is affixed to each object which is to be monitored. When an interrogating device is placed near the sensors, a resonance can be measured whose frequency characteristics change in a reproducible manner with the relative displacement of the sensors. The resulting resonance characteristics can be calibrated in such a way as to enable the displacement of the objects to be determined.

6974415, Dec 13, 2005

May 22, 2003

10/444202

Stephen Anthony Cerwin - Mico TX, US
David B. Chang - Tustin CA, US
James E. Drummond - Lincoln City OR, US
Jane F. Emerson - Irvine CA, US
Stuart McNaughton - Beaverton OR, US

Magnetus LLC - Irvine CA

A61B008/00
A61B005/04

600437, 600407

Ultrasound induced by RF irradiation within FDA exposure limits is produced with sufficient signal-to-noise ratio to allow acquisition of sub-millimeter resolution images within practical time frames.

7288945, Oct 30, 2007

Aug 11, 2005

11/201753

Robert E. Martinez - Austin TX, US
Stephen A. Cerwin - Mico TX, US
Todd H. Goyen - San Antonio TX, US

Southwest Research Institute - San Antonio TX

G01R 27/26

324663, 324672, 324679, 324688

Methods and systems are described for efficiently detecting an object. The system includes at least one electrode for measuring a displacement current. The at least one electrode is coupled to a floating ground configuration provided by an op-amp, where the inverting node of the op-amp is coupled to electrode and the non-inverting node is coupled to a signal generator. The system may include a single capacitance sensor for detecting an object. Systems may include a plurality of capacitance sensors in an array configuration for detecting an object.

7372031, May 13, 2008

Mar 20, 2006

11/384574

Stephen A. Cerwin - Mico TX, US
David B. Chang - Tustin CA, US

Southwest Research Institute - San Antonio TX

G01J 1/00

2503361

A sensitive photon detection system generates an electronic photon sensor signal as a K factor times a number N photons per unit time. The system is configured by combining a separate optical amplifier with a gain factor K with a photo detector with a gain factor K such that K may be realized as the product of K and K. The values of K and K are chosen to meet a predetermined K while optimizing a signal quality of the photon sensor signal. The optical amplifier may be preceded by a photon gathering device and/or a light chopping device to further optimize system performance. Further, the photon sensor signal may be further processed analog circuitry or may be digitized and processed using digital signal processing to generate an enhanced photon sensor signal with enhanced signal quality by adding gain and/or bandwidth limiting.

7420195, Sep 2, 2008

Dec 21, 2005

11/315540

Stephen A. Cerwin - Mico TX, US
Thomas C. Untermeyer - Lakehills TX, US
David Bing Jue Chang - Tustin CA, US
Thomas J. Warnagiris - San Antonio TX, US

Southwest Research Institute - San Antonio TX

F23N 5/08

250554, 2502141, 25033915, 89 111, 356313

Methods for remotely detecting a gun muzzle flash, using frequency-optimized detection methods. Small explosive charges are best detected at I/R and visible wavelengths, using optical detectors, whereas large explosive charges may also be detected with antennas. Details of the time course and spectral properties of the flash can be used to distinguish gun muzzle flashes from other radiation.

7528762, May 5, 2009

Mar 30, 2006

11/278056

Stephen A. Cerwin - Mico TX, US

Southwest Research Institute - San Antonio TX

G01S 13/90
G01V 3/12
G01V 3/16
G01V 3/17

342 22, 342 25 R, 342159

Methods and systems for using ground penetrating radar (GPR) to obtain subsurface images. The depression angle, frequency, and polarization can all be adjusted for the soil conditions at hand. In particular, the depression angle is set at the “pseudo-Brewster angle” for improved ground penetration.