Noise floor comparison of optical displacement measuring interferometer between air and vacuum environments

2021 ◽  
Author(s):  
Masato Aketagawa ◽  
Kousuke Sakasai ◽  
Masato Higuchi ◽  
Dong Wei ◽  
Thanh D. Nguyen
Keyword(s):  
Noise Floor ◽  
Optical Displacement

3D localization for subcentimeter-sized devices

2021 ◽  
Vol 64 (3) ◽  
pp. 117-125
Author(s):  
Rajalakshmi Nandakumar ◽  
Vikram Iyer ◽  
Shyamnath Gollakota
Keyword(s):  
Metropolitan Area ◽  
Ultra Wideband ◽  
Phase Information ◽  
Noise Floor ◽  
Localization System ◽  
Coin Cell ◽  
3D Localization ◽  
Button Cell ◽  
Iot Devices ◽  
5 Ghz

The vision of tracking small IoT devices runs into the reality of localization technologies---today it is difficult to continuously track objects through walls in homes and warehouses on a coin cell battery. Although Wi-Fi and ultra-wideband radios can provide tracking through walls, they do not last more than a month on small coin and button cell batteries because they consume tens of milliwatts of power. We present the first localization system that consumes microwatts of power at a mobile device and can be localized across multiple rooms in settings such as homes and hospitals. To this end, we introduce a multiband backscatter prototype that operates across 900 MHz, 2.4 GHz, and 5 GHz and can extract the backscatter phase information from signals that are below the noise floor. We build subcentimeter-sized prototypes that consume 93 μW and could last five to ten years on button cell batteries. We achieved ranges of up to 60 m away from the AP and accuracies of 2, 12, 50, and 145 cm at 1, 5, 30, and 60 m, respectively. To demonstrate the potential of our design, we deploy it in two real-world scenarios: five homes in a metropolitan area and the surgery wing of a hospital in patient pre-op and post-op rooms as well as storage facilities.

scholarly journals Upconversion Spectral Rulers for Transcutaneous Displacement Measurements

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3554
Author(s):  
Melissa M. Suckey ◽  
Donald W. Benza ◽  
John D. DesJardins ◽  
Jeffrey N. Anker
Keyword(s):  
Optical Measurement ◽  
Optical Measurements ◽  
Small Displacement ◽  
Simple Method ◽  
Low Background ◽  
X Ray ◽  
Optical Displacement ◽  
Spectral Peaks ◽  
Displacement Measurements ◽  
Minimal Intensity

We describe a method to measure micron to millimeter displacement through tissue using an upconversion spectral ruler. Measuring stiffness (displacement under load) in muscles, bones, ligaments, and tendons is important for studying and monitoring healing of injuries. Optical displacement measurements are useful because they are sensitive and noninvasive. Optical measurements through tissue must use spectral rather than imaging approaches because optical scattering in the tissue blurs the image with a point spread function typically around the depth of the tissue. Additionally, the optical measurement should have low background and minimal intensity dependence. Previously, we demonstrated a spectral encoder using either X-ray luminescence or fluorescence, but the X-ray luminescence required an expensive X-ray source and used ionizing radiation, while the fluorescence sensor suffered from interference from autofluorescence. Here, we used upconversion, which can be provided with a simple fiber-coupled spectrometer with essentially autofluorescence-free signals. The upconversion phosphors provide a low background signal, and the use of closely spaced spectral peaks minimizes spectral distortion from the tissue. The small displacement noise level (precision) through tissue was 2 µm when using a microscope-coupled spectrometer to collect light. We also showed proof of principle for measuring strain on a tendon mimic. The approach provides a simple method to study biomechanics using implantable sensors.

Simulation of the Characteristics of a Magneto-Optical Displacement Transducer

2016 ◽  
Vol 59 (8) ◽  
pp. 832-837 ◽  
Author(s):  
S. A. Matyunin ◽  
M. V. Stepanov ◽  
O. G. Babaev
Keyword(s):  
Displacement Transducer ◽  
Optical Displacement

Micromachined microphones with diffraction-based optical displacement detection

2005 ◽  
Vol 118 (5) ◽  
pp. 3000-3009 ◽  
Author(s):  
Neal A. Hall ◽  
Baris Bicen ◽  
M. Kamran Jeelani ◽  
Wook Lee ◽  
Shakeel Qureshi ◽  
...  
Keyword(s):  
Optical Displacement

Enhanced Sensitivity and Reduced Noise Floor in Magnetoelectric Laminate Sensors by an Improved Lamination Process

2011 ◽  
Vol 94 (11) ◽  
pp. 3738-3741 ◽  
Author(s):  
Menghui Li ◽  
David Berry ◽  
Jaydip Das ◽  
David Gray ◽  
Jiefang Li ◽  
...  
Keyword(s):  
Noise Floor ◽  
Enhanced Sensitivity ◽  
Lamination Process

Techniques for Schumann Resonance Measurements: A Comparison of Four Amplifiers With a Noise Floor Estimate

2015 ◽  
Vol 64 (10) ◽  
pp. 2759-2768 ◽  
Author(s):  
Jose A. Gazquez Parra ◽  
Manuel Fernandez Ros ◽  
Nuria Novas Castellano ◽  
Rosa M. Garcia Salvador
Keyword(s):  
Schumann Resonance ◽  
Noise Floor

Noncontact optical displacement measurements by dynamic contrast auto focusing for slow oscillatory motion

2021 ◽  
Vol 60 (12) ◽  
Author(s):  
Evgeniy Makagon ◽  
Sergey Khodorov ◽  
Anatoly Frenkel ◽  
Leonid Chernyak ◽  
Igor Lubomirsky
Keyword(s):  
Oscillatory Motion ◽  
Optical Displacement ◽  
Displacement Measurements ◽  
Auto Focusing
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