Opportunity for Partnership
A Revolutionary Multiple-Wavelength Light Detection and Ranging (LIDAR) System for Vegetation Mapping
NASA Goddard Space Flight Center invites companies to license its new active vegetation index measurement technique that enables remote differentiation of vegetative and non-vegetative surfaces. The first method of its kind, this patent-pending spectral-ratio biospheric Light Detection and Ranging (LIDAR) system uses coded signals on two lasers, enabling users to both discriminate between and monitor changes in photosynthetic surfaces. This unique process can greatly benefit environmental and agricultural mapping and monitoring as well as other commercial and government efforts.
How it works
The Normalized Difference Vegetation Index measures the reflectivity and absorption of chlorophyll-containing vegetation. Chlorophyll absorbs visible light for use in photosynthesis, illustrated by blue and red peaks near 0.4 and 0.67 _m. The leaves strongly reflect near-infrared (NIR) light from 0.7 to 1.2 _m. The transition around 0.7 _m is known as the red edge. Less reflected radiation in red wavelengths versus NIR wavelengths indicates healthy and dense vegetation. If the difference between the intensity of the reflected wavelengths is small, then the vegetation is presumed sparse, dead or absent. Using a wavelength close to the red edge provides an unambiguous signal.
Goddard’s technology provides a land-surface LIDAR method that uses spectral reflectance to make these determinations. The process calls for the use of two telecommunications lasers (O-band and C-band), both of which are frequency doubled, providing imaging wavelengths of approximately 665 nm and 775 nm. Light from both lasers is rapidly modulated to provide precise range information without requiring powerful short laser pulses. Calculating a ratio of the returned signals from these two wavelengths enables vertical resolution of, and differentiation between, vegetative and non-vegetative surfaces. Because the method uses two wavelengths that are absorbed differently by chlorophyll-containing (vegetative) surfaces, changes in the vegetation itself can be determined and monitored.
Why it is better
Typical imaging and mapping LIDAR systems use a single-wavelength approach that is capable of detecting altitude differences between the ground and objects above the ground. This difference is used to infer the height of vegetation assumed to be in the field of view, but it does not account for dead trees, rocks, buildings, or other structures. Therefore, these methods cannot readily distinguish between vegetation and non-vegetative surfaces. Precursor LIDAR techniques were able to discriminate vegetative ranges but could not monitor relative changes to the vegetation itself. Using other wavelengths may make it difficult to distinguish between living vegetation and some common, non-vegetative surfaces that have similar reflectance ratios.
Contrasted with these methods, Goddard’s paired-wavelength approach provides a proven method that enables both determination and tracking of vegetative land surfaces.
Benefits
- Multiple wavelength: Uses multiple-wavelength LIDAR, enabling direct discrimination of vegetative from non-vegetative surfaces as well as monitoring of vegetation changes
- Reliable: Employs commercial off-the-shelf lasers with known reliability
- Three-dimensional: Provides a 3-D view of chlorophyll in plant canopies, enabling users to obtain information about surface type as well as volume
- Accurate: Provides unprecedented information for calibration of passively acquired multispectral vegetation data
- Proven: Performs as expected as demonstrated during NASA testing
Goddard’s technology has great potential for airborne mapping and monitoring of topography and ecosystem changes for applications such as:
- Agriculture
- Forestry inventory
- Precision farming
- Environmental monitoring
- Biomass measurements
- Habitat quality assessments
- Ecosystem damage assessments
- Mapping
- Surface topography beneath vegetation
- 3-D surface details of forested flood plains and wetlands
- Mixtures of artificial, geological and living features
Please mention that you read about it in Technology Innovation.
Real-Time Optical Parylene Thickness Sensor
NASA Goddard Space Flight Center invites companies to license this Real-Time Optical Parylene Thickness Sensor technology. This highly accurate sensor greatly improves thickness control in parylene and other polymer deposition systems, providing alerts of batch-to-batch process variations and enabling precise and repeatable controls.
With accuracy greater than 95 percent, it provides real-time measurements of deposited film thickness ranging from .5 to 30 microns. In addition, this sensor technology lowers production time and cost by reducing errors and material waste. Because advanced applications of thin-film parylene are limited by the precision of the deposition, enhancing thickness monitoring and deposition may facilitate new applications for this material.
Goddard’s new Optical Film Thickness Sensor can be used with parylene and other polymer deposition processes. The sensor optically measures the increasing parylene film thickness on the face of the sensor head. The polished face of the sensor head uses one or more polished optical fibers. As film deposits on the fibers, it creates a polymer Fabry-Perot cavity, which can be interrogated and measured. This measurement is directly correlated to the film thickness and maintains a thermally identical coating surface as the hardware being coated.
How it works
The sensor is secured to the coating chamber feed-through and has two optical fibers embedded into a silica base plate that has been polished to optical flatness. Light travels through the optical fibers to the base plate where the parylene film is being deposited. Because of the change in the indices of refraction, a portion of the light is reflected both where the parylene film meets the air and where the parylene film meets the optical fiber. These reflections have an optical path difference and, therefore, form an interference pattern. These resulting interference fringes are measured using basic interferometric techniques to produce real-time, accurate measurements that are directly correlated to the film thickness. Additional fibers could be added for even greater accuracy. Because this sensor works in real time within the deposition chamber, it renders inconsequential the environmental factors experienced with other measurement techniques that affect deposition uniformity and accuracy.
Why it is better
Of the available thickness monitors, including quartz crystal oscillators and conductivity devices, none can provide the level of accuracy needed for parylene films—particularly when it is used in nanoscale devices such as microtubules and microfluidic chips.
This sensor is also versatile: In addition to parylene, it can be readily applied to other deposited films including polymers. Adaptations only require the deposited material’s index of refraction.
NASA Goddard Space Flight Center is seeking patent protection for this technology.
Benefits
- Lowers costs: By accurately depositing the right amount of parylene dimer, costs can be controlled and even lowered since undershooting and overshooting are unnecessary. This technology uses existing hardware that is widely used in the optics industry.
- Saves time: Real-time processing eliminates post-deposition monitoring. Run times are shortened because rerunning to add more material is eliminated.
- Enables new applications: Enhanced thickness monitoring enables the advancement of existing technologies.
- Enables advancement toward ISO 9000 certifications: By creating repeatable standards and reproducible measurements for film thickness, this technology can help companies advance towards achievement of ISO 9000 certification.
- Microelectromechanical systems (MEMS): Microscale devices such as microtubes and microfluidic and micro-optical devices
- Automotive: Sensors and protective coatings for automotive electronics
- Aerospace: Sensors and protective coatings for electronics and other equipment
- Electronics: Stronger wire bonds, moisture barriers, dielectric coatings and device dielectric layers (potential)
- Medical: Biocompatible coatings for medical devices (e.g., coronary stents, prosthesis, catheters, etc.)
Please mention that you read about it in Technology Innovation.
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