Headwall Photonics Blog

Smaller, Lighter, Better: Hyperspectral on UAVs

Posted by Christopher Van Veen on Fri, Aug 08, 2014

At Headwall we've been busy listening to the market. When it comes to airborne remote sensing, the market is telling us that they favor UAVs (unmanned aerial vehicles) of all kinds: fixed-wing, multi-rotor, and so on. There's no end to the number of companies producing UAVs globally. Because many UAVs produced today are very small and affordable they are 'within reach' of those with even modest means. Universities represent one key market where the use of UAVs is rapidly increasing. Full of scientists and research departments, universities around the globe see these small and light UAVs as a perfect platform from which to launch their exploratory studies. They are affordable, easy to assembly and transport, and (especially with multi-rotor models) can take off and land within a very small footprint.

UAV with NanoBut alongside all this enthusiasm for UAVs, there are many who frown upon these airborne vehicles and see them as a nuisance. Indeed, they can be a nuisance when used for trivial pursuits. In densely-populated areas they certainly can be more than an annoyance...they can be dangerous. But largely, the work we are seeing our customers undertake with hyperspectral imagers attached to UAVs is very valuable work indeed. And it takes place far from the hustle and bustle of any urban landscape. For example, precision agriculture is made more valuable because there are key indices to plant health and physiology that are readily seen from above than from below. Certain disease conditions are ‘visible’ using hyperspectral imaging, especially with high spectral and spatial resolution found on all Headwall sensors.  Other research pursuits include environmental analysis, geology, pollution analysis, and so many more. These are very good and valuable scientific efforts made moreso by the UAVs that enable these precision instruments to 'fly.' The marriage between hyperspectral and UAV seems to be a perfect one, especially when you consider how much ground can be covered with one of these flying wizards. And especially when you realize that hyperspectral imaging fundamentally requires that movement needs to occur. In other words, hyperspectral was meant for airborne deployment. Where a Jeep can’t go, a UAV can. And furthermore, more ground can be covered with a UAV, meaning more efficient data collection over rugged and inaccessible landscapes.

Nano-HyperspecAs UAVs get smaller and lighter, users run headlong into the issue of payload: UAVs are limited with respect to what they can lift. Whatever else a UAV is asked to carry, it needs to lift batteries. Then comes the instrumentation. Headwall’s Nano-Hyperspec was just introduced for the VNIR (400-1000nm) spectral range. Most (but not all) of the things a research scientist might wish to ‘see’ are visible in this spectral range. But we did a couple things with Nano-Hyperspec that helps the payload issue. First, the size and weight are well below previous sensor offerings. Its size (including lens) is a scant 3” x 3” x 4.72” (76.2mm x 76.2mm x 119.2mm), and its weight is less that 1.5 lb. (0.68kg). Best of all, this includes on-board data storage of 480GB. That’s about 130 minutes at 100fps.

Aside from making Nano-Hyperspec smaller and lighter than other hyperspectral sensors, a key differentiator comes from embedding the data storage within the enclosure while providing multiple attach points for the GPS/INU. Another key attribute is the inclusion of the full airborne version of Headwall’s Hyperspec III software, which includes a polygon flight tool for sensor operation and a real-time Ethernet Waterfall display. While the work to shrink the size and weight of Nano-Hyperspec is valuable by itself, it does allow the user more room and available payload to carry other instrumentation. Hyperspectral combined with LiDAR and thermal imaging is an extremely valuable package that is made possible thanks to the overall size/weight reduction of Nano-Hyperspec and the embedding of the data storage/management capabilities (which were contained within a separate enclosure previously).

Hyperspec III software gives users full control over data acquisition, sensor operation, and datacube creation in ENVI-compatible format. Hyperspec III also works in full conjunction with the GPS that can be paired with the sensor as an available Airborne Package. In this optional package, customers are able to take advantage of real-time computation of inertial enhanced position/velocity, ~161dBm tracking sensitivity, accurate 360-degree #D orientation output of attitude and heading, correlation of image data to GPS data, and much more. During post-processing, the Airborne Package also effortlessly handles radiometric calibration and conversion as well as orthorectification.

 

 


Tags: Airborne, Remote Sensing, UAV, agriculture, precision agriculture

Hyperspectral Takes Wing Over Ontario!

Posted by Christopher Van Veen on Thu, May 01, 2014

UASUnder cloudless skies in Ontario recently, Headwall achieved a very notable milestone: we became the first to fly both hyperspectral and LiDAR aboard a small, fully integrated handheld UAS. The test flights not only verified the reliable airworthiness of the system but also the ability to collect valuable hyperspectral and LiDAR data in real time.

Integration is key, because all of this specialized data-collecting instrumentation needs to fit the payload parameters with respect to size and weight. With UAS systems shrinking in size and weight, payloads need to follow suit. As prime contractor for this complete airborne system, Headwall is able to get end-users up and running quicker than ever. Time to deployment is reduced by months thanks to the work Headwall is doing to engineer optimized solutions that meet specific remote-sensing needs.

“The variety of applications for this type of integrated airborne system are numerous,” said Headwall CEO David Bannon. “Precision agriculture is a key one we’re seeing on a global scale, but geology, pipeline inspection, environmental research, pollution analysis are others.” Today’s UAS is smaller, lighter, and more affordable than ever, which makes it a perfect platform from which to carry precise imaging instruments such as hyperspectral and LiDAR. “We’ve always been a pioneer in the area of small hyperspectral sensors for just these kind of deployments,” noted Bannon. “Our strength comes from understanding what our users want to do and then engineering a complete airborne solution that meets that need.”

Chris Van Veen, marketing manager at Headwall, was on site to record and document the test flights. “A fully integrated package like this represents a new frontier for remote-sensing scientists who now have an airborne research platform that goes wherever they do,” says Chris. “Watching this fly and collect data in Canada was a thrill because it was visible testimony to all our integration work.”

The entire payload aboard this particular UAS is less than ten pounds, which includes hyperspectral, GPS/IMU, LiDAR, and computing hardware. Besides making sure these elements are small and light enough, the challenge of integrating everything with an eye toward battery lifetime is also Headwall’s to manage. “We know our remote-sensing users have very important work to do, and they need sufficient power not only to fly but also to operate the instruments,” said Bannon. One way to meet this challenge head-on is to make sure the hyperspectral sensor provides a very wide field of view with precise imagery from one edge to the other. “If you can assure outstanding image-collection across a wide field of view, and then provide orthorectification of that data, you’re covering more ground for each flight swath.”

Fundamental to accomplishing this is Headwall’s approach to optics, which is both simple and elegant. “Our diffractive optics approach uses no moving parts, which, in an airborne application, means robustness and reliability,” said Bannon. Inside each Micro-Hyperspec sensor is a precise and small holographic diffraction grating that manages incoming light with exceptional fidelity. These sensors are ‘tuned’ for the spectral range of interest to the user. “Depending on what the user wants to ‘see,’ he may need a VNIR sensor that operates from 380-1000 nanometers,” said Bannon. The spectral signature of a certain disease condition on a crop tree will determine the spectral range of the sensor, for example. Headwall has also introduced a wideband VNIR-SWIR sensor package that covers from 400-2500 nanometers. This co-registered hyperspectral instrument will be very popular with users who need broad coverage but need a small, light, and affordable instrument to do it with.

The following video will give you a peek into how flight testing went in Ontario.

Tags: hyperspectral, Airborne, Remote Sensing, UAS, UAV, agriculture

Hyperspectral Sensors for UAV Applications

Posted by Christopher Van Veen on Wed, Feb 19, 2014

The scientific research community is beginning to understand and embrace hyperspectral imaging as a useful tool for a few primary reasons. First, sensors are more affordable than ever. Originally conceived as multi-million-dollar ISR platforms for defense applications, hyperspectral imagers have been successfully ‘commercialized’ over the past few years. Scientists typically embracing RGB or multispectral technology before can now acquire hyperspectral sensors at affordable price points.

Hyperspectral sensors of the ‘pushbroom’ type produced by Headwall require motion to occur. That is, either the sensor flies above the field of view, or the field of view moves beneath the sensor. For UAV applications, Headwall’s small and lightweight Micro-Hyperspec is the platform of choice. Available in the VNIR (380-1000nm), NIR (900-1700nm), and SWIR (950-2500nm) spectral ranges, the sensor is truly ‘SWaP-friendly.’

Spectral range is often where the decision-making starts. The chemical fingerprint—or spectral signature—of anything within the field of view will lead the user in one direction or another. For example, a certain disease condition on a tree canopy may become ‘visible’ within the SWIR spectral range (950-2500nm). Similarly, a certain mineral deposit may become ‘visible’ in the VNIR range (380-1000nm). One approach to ensuring the spectral ‘fidelity’ of images collected by the sensor makes use of ‘diffractive optics’ comprising aberration-corrected holographic gratings. This ‘Aberration-corrected concentric’ design is shown below.

concentric imager

There are several advantages to this ‘reflective’ approach. First, the design is simple, temperature insensitive, and uses no moving parts. This assures robustness and reliability in airborne situations. Second, diffraction gratings can be made very small so that the instruments themselves can be small and light; in other words, capable of fitting the new class of lightweight, hand-launched UAVs. Third, the design optimizes technical characteristics that are most important: low distortion for high spatial and spectral resolution; high throughput for high signal-to-noise; and a tall slit for a wide field-of-view. Because the design is an all-reflective one, chromatic dispersion is eliminated and excellent focus is assured across the entire spectral range.

Many within the environmental research community and across ‘precision agriculture’ prefer to use UAVs as their primary airborne platform. They are more affordable than fixed-wing aircraft and easy to launch. But as UAVs get smaller and lighter, so must the payloads they carry. And integrating the sensor into the airframe along with other necessities such as LiDAR, power management/data collection hardware, and cabling can be a daunting task (Figure 3). Orthorectification of the collected data is another key requirement, which is the means by which the hyperspectral data cube is ‘managed’ into useful information that has been ‘corrected’ for any airborne anomalies. In other words, the collected hyperspectral data needs to be ‘true’ to what’s actually within the field of view.

 Micro Hyperspec

Acquiring a UAV and a hyperspectral sensor won’t assure compatible performance, and a high level of ‘integration work’ is needed. The UAV community and the hyperspectral sensor community are both challenged with pulling everything together. Recognizing this, Headwall Photonics is taking an industry-leading position as a supplier of fully integrated airborne solutions comprising the UAV, the sensor, the power and data management solution, cabling, and application software. The result is that users are flying sooner and collecting better hyperspectral data than ever before.

Type of UAV is very often one of the first decisions a scientist will need to make. Fixed-wing and multi-rotor are the two general categories, with numerous styles and designs within each. In-flight stability and flight-time duration are both paramount concerns, and this is where payload restrictions will often point toward one or the other. Multi-rotor UAVs launch and land vertically, so this type will be favored in situations where space is tight. Conversely, a fixed-wing UAV requires suitable space to launch and land but can provide longer flight duration and carry a heavier payload. The wide field-of-view characteristic of the concentric imager allows a UAV to ‘see’ more ground along its flight path.

Integrated airborne package

Two other key areas managed through Headwall’s integrative process are data management and application software. While a separate subsystem is used to control the sensor operation and store the hyperspectral data, the direction is clearly toward on-board integration of these capabilities. Flash storage and solid-state drives will soon make it possible for the sensor to ‘contain’ all the related functionality that now needs to be contained in a separate module. This will clearly lighten the overall payload, reduce battery consumption, and boost airborne flight time.

Headwall’s Hyperspec III software represents a complete, modularized approach to the management of hyperspectral data. Orthorectification is one such module within the software suite that removes the unwanted effects airborne behavior. The resultant orthorectified images have a constant scale wherein features are represented in their 'true' positions. This allows for the accurate direct measurement of distances, angles, and areas. Other aspects of the software suite can be used to control GPS/IMU devices, control multiple sensors simultaneously, and save polygons (A Google-map-enabled tool that allows the user to define geographic coordinates).

 

 

Tags: hyperspectral imaging, hyperspectral, Airborne, Remote Sensing, Micro Hyperspec, agriculture, diffraction gratings, precision agriculture

Remote Sensing: All Eyes on Munich

Posted by Christopher Van Veen on Fri, Jul 20, 2012

The IEEE is an esteemed organization with top-notch events held worldwide. These events draw experts from across industry, government and education.

One of these events is happening next week, in Munich, Germany. The IEEE's International Geoscience and Remote Sensing Symposium (IGARSS) will probably see its biggest attendance ever, as the evolution of unmanned aerial vehicles (UAVs) melds with needs of the remote sensing community. Headwall Photonics will be in booth #18.

IGARSS 2012Much of what scientists want to analyze is best done from above. This holds true for oceanography, atmospheric research, precision agriculture, minerals and mining, and forestry management. Now that commercial UAVs are becoming more affordable and regulations governing their use more ‘mainstream,’ the door is wide open for a fascinating amount of quality research helped along by these small, pilotless aircraft.

Hyperspectral sensors represent a highly desired piece of precision instrumentation carried aloft by UAVs. Why? Because they can extract a tremendous amount of data based on the spectral makeup of what is within the field of view. What the human eye—or even infrared—cannot see, hyperspectral sensors can. Small, lightweight, and extremely precise, Headwall’s Micro Hyperspec is favored for its ability to offer several attractive capabilities. First is its tall slit, which gives the sensor a wide field of view. The wider the field of view, the more precise the hyperspectral data is from a given altitude. Looking down Hyperspectral imaging from UAVsfrom above, UAVs can make fewer passes over a plot of land if the resolution to either side of the flight path is very wide. In short, more territory can be covered in less time.

Another highly desired characteristic is spatial and spectral resolution, which determines how faithful the hyperspectral data is. The beauty of a hyperspectral sensor is that it can delineate what it ‘sees’ with a tremendous degree of resolution. For example, higher resolution can mean the difference between simply distinguishing disease conditions and determining what those diseases are. Or, determining good soil conditions from bad.

While affordable UAVs are all the rage at present, the beauty of hyperspectral imaging is that instruments can be made small and rugged to fit specific payload requirements. 'Size, Weight & Power' (referred to as 'SWaP) describes the continuous desire to make payloads as small, lightweight, and as power-efficient as possible. These characteristics hold true for any airborne vehicle aside from a UAV, whether a fixed-wing aircraft, a high-altitude reconnaissance plane, or a satellite. Headwall Photonics has hyperspectral instruments deployed successfully in all these platforms.

 

 


Tags: hyperspectral imaging, hyperspectral, Headwall Photonics, Airborne, Remote Sensing, Sensors, Sensing, Satellites, UAV, agriculture

Hyperspectral Imaging - Next Generation Machine Vision Platform for Food Safety and Quality

Posted by David Bannon on Tue, Jun 26, 2012

Bosoon Park, author of this blog entry, works as an Agricultural Engineer on behalf of the USDA in Georgia. He has done extensive research on hyperspectral and Raman imaging as it applies to food inspection and agriculture. Author of numerous published papers on the subject, Bosoon will be co-presenting a discussion on hyperspectral imaging at the annual conference of the American Society of Agricultural and Biological Engineers to be held in Dallas July 30 through August 2.

USDA At USDA, our work revolves around making sure that the foods we harvest and eat are safe, high quality, and healthy. Our mission is twofold: ensuring and improving the safety of food and feed, and ensuring and improving the quality and economic value of food and crops.

There are very important inspection steps between ‘farm’ and ‘fork,and the USDA invests considerable time looking at new technologies that can help. Hyperspectral & Raman imaging (both imaging spectroscopy techniques) can provide valuable inspection data based on the chemical composition of agricultural products that traditional machine vision systems cannot provide. 

During the past decade, USDA has worked with companies such as Headwall Photonics to develop hyperspectral technologies for in-line food safety inspection. Our work focuses on contaminant detection during in-line processing, which the Hyperspec Inspector allows us to do. Our researchers are expanding hyperspectral imaging technology to rapidly detect foodborne pathogens at a microscopic level.  Hyperspectral imaging has tremendous potential for the food industry in terms of safety inspection and quality control by analyzing spatial and spectral characteristics of agricultural products.  We are also exploring handheld hyperspectral instruments fully integrated with operating software for field use.

Raman spectrometers will also detect foodborne pathogens since their scattering phenomena respond very well to particular laser-lighting sources. USDA researchers have proved the concept to identify bacterial species and foodborne bacterial serotypes with surface-enhanced Raman scattering (SERS). This is an emerging area of focused research for improved food safety.

In an effort to educate and inform, several of us from USDA are preparing a short course on ‘hyperspectral imaging’ at the upcoming American Society of Agricultural and Biological Engineers (ASABE) conference July 30-August 2 in Dallas. Thanks to help from Headwall Photonics in commercializing and economizing the technology, we’re able to research and test hyperspectral and Raman instruments so that they can become mainstream across food-processing industries ranging from poultry to specialty crops.

Tags: hyperspectral imaging, hyperspectral, Sensors, SWIR, food processing, agriculture, Raman, USDA, plant phenotyping, Raman imaging

Hyperspectral Imaging & Agriculture: A Perfect Match

Posted by Christopher Van Veen on Wed, May 02, 2012

Spectral imaging and agriculture seems to be a perfect match. Technologies and techniques such as hyperspectral in-line inspection and Raman imaging instrumentation are well suited to very high-speed processing environments such as those found in agricultural processing plants for meat, poultry, and specialty crops.

USDAHeadwall recently had the opportunity to meet with USDA Deputy Secretary Kathleen Merrigan at the Washington DC offices of the USDA.  As stated by Dr. Merrigan, a very high priority for the USDA are issues pertaining to improved food safety and quality all within an environment of challenging fiscal alternatives.  Given the introduction of the Food Safety Modernization Act and USDA-led initiatives such as the HAACP-Based Inspection Pilot (also known as HIMP), there is an ever-growing industry requirement for high-speed machine vision instruments that are capable of supporting food safety and food quality standards accurately and cost-effectively.

Hyperspec InspectorHeadwall has a unique research and development relationship with the USDA whereby Headwall develops hyperspectral instrumentation specifically for in-line inspection in agriculture applications.  These represent very harsh environments, and having a stable spectral imaging platform that addresses multiple spectral ranges is very important for critical processing and inspection applications.  One of these is Hyperspec Inspector (shown), which is a complete hyperspectral imaging solution meant precisely for this kind of industrial environment. Strong collaboration and joint research with the USDA has strongly positioned Headwall’s technology as a proven and cost-effective alternative for food processors.

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Tags: hyperspectral imaging, hyperspectral, Headwall Photonics, Sensors, agriculture

Small UAVs - Precision agriculture & hyperspectral remote sensing

Posted by David Bannon on Mon, Apr 09, 2012

Micro Hyperspec UAV Picture 2Offering improvements in agricultural yields and precision farming, hyperspectral sensors allow producers and processors to make the foods we eat safer along with providing the advantages of higher quality and hopefully, better taste.  Based in Massachusetts, Headwall Photonics, designs and manufactures small, lightweight sensors that are deployed aboard airborne platforms ranging from piloted aircraft to unmanned aerial vehicles (UAVs). With experience developed within the military sector, the company has established quite a business enabling the commercial use of very small, cost-effective UAVs for remote sensing and agriculture applications.

In the same way that food-processing lines are evolving from straight-forward machine-vision systems to spectral imaging, many agriculturalists and food producers are moving beyond simple appearance and color measurement to more advanced hyperspectral imaging. The richness of the data collected offers farmers a sense of what to plant, where to plant, and when to harvest. High-value crops such as pecans, grapes, walnuts and others need to be managed with precision to yield a profitable harvest. Nutrient levels, ripeness, and disease conditions can be ‘seen’ by hyperspectral sensors based on the chemical “fingerprint” of the crops rather than on the visual appearance; thus offering the ability to implement cost-effective solutions early in the growth cycle of the harvest.

Since these imaging sensors can be and are rapidly being deployed aboard inexpensive UAVs, hundreds of acres can be surveyed and monitored very quickly. The data-processing power coupled to these hyperspectral sensors means that more actionable crop and agricultural information can be obtained. The result is better overall crop management across the farming and food production industries. Where famine relief is acute, airborne hyperspectral sensors quickly lead to better decisions about what crops to plant, where to plant them, and when to harvest them. The specific ‘spectral signatures’ of diseased plants, contaminants, and ripeness conditions mean that hyperspectral technology can clearly be used to ensure healthier foods for all and a more profitable and timely crop harvest.

As a previous topic, Headwall mentioned an important specialty crop in the United States being grape production and vineyard management. One of Headwall’s hyperspectral customers, VineView Scientific Aerial Imaging, is a company that uses high-resolution, scientifically calibrated data products to assist framers in crop uniformity optimization, irrigation management, and harvest planning. “Hyperspectral data allows us to provide more specific actionable information to our clients who manage high-value crops,” said Dr. Matthew Staid, President of Saint Helena, CA-based VineView. The Headwall airborne hyperspectral sensors can be mounted on small UAVs or manned aircraft and means that VineView cannot only map vigor or stress within crops but can better identify the specific causes of those stresses. 

Headwall continues to advance the agriculture and remote sensing industries through the deployment of cost-effective hyeprspectral sensors that have a positive impact on farmers, food processors, and agricultural research scientists around the world.

To speak with an application engineer, click here ...

Tags: hyperspectral imaging, Airborne, Remote Sensing, SWIR, agriculture