The Student Perspective: Imaging Science at RIT
Student Stories
Graduate
Remote Sensing

I am a third year PhD student at Rochester Institute of Technology’s Center for Imaging Science. I chose the Imaging Science degree program because quite simply, nothing else like it exists.

Aug. 26, 2013
David Kelbe

This was the first, and remains the only program of its kind in the country.

We study in depth the physics-driven principles of imaging, from beginning to end. This comprehensive, systems-based approach to imaging sets us apart from other similar degree programs: Quite simply, the science of imaging is most powerful when it is understood as a chain of deeply interconnected links (e.g., image system engineering, optical image formation, data processing, etc.)  Any chain is only as strong as its weakest link. So our coursework focuses on understanding in depth the fundamental concepts of each link in the imaging chain, and how they interact with each other in the context of a specific problem or application.

Terrestrial laser scanning to gather ground truth structural data in conjunction with airborne data. Photo: David Kelbe.

This precise, mathematical, framework allows us to better understand and harness the complex data that is collected, and thus more aptly address the given application or objective. I am continually amazed by what can be done with this technology.

At RIT, this theoretical background is combined with an intensely practical and applied engineering focus. We are at the cutting edge of utilizing the latest technology (or designing and building it ourselves) with the end goal of solving problems. Once you know and understand how imaging systems work, you can apply this fundamental knowledge to a range of fascinating applications and objectives.

Photo at right: Terrestrial laser scanning to gather ground truth structural data in conjunction with airborne data. Photo: David Kelbe.

To put it succinctly, we are problem solvers.

We understand each piece of the puzzle and how they all fit together, and so can tackle an incredibly diverse range of imaging-related problems with the core fundamental background.

This versatility is one of the things I love about the Imaging Science program. With a fundamental, systems-based understanding of imaging, you can apply these tools to a diverse range of applications. This really translates into career flexibility. You have the freedom to follow your career goals and interests as they evolve and change, without worrying about being pigeonholed into a single discipline.

To give you an example from my personal experiences, here is a snapshot of my current and future interests:

In the fuselage of NEON's airborne imaging spectrometer. (The large instrument is the spectrometer and waveform lidar, which is mounted to look out of a hole in the bottom of the aircraft). Photo: David Kelbe.

My dissertation research involves using laser scanning for structural ecological assessment. We have developed a portable laser-scanning system for rapid three-dimensional assessment of below-canopy forest structure. I am using this technology to help better understand the next generation of airborne and space-borne sensing systems.

Photo at left: In the fuselage of NEON’s airborne imaging spectrometer. (The large instrument is the spectrometer and waveform lidar, which is mounted to look out of a hole in the bottom of the aircraft). Photo: David Kelbe.

But while my dissertation work focuses on ecological and laser scanning, I’ve also had the opportunity to become involved in other imaging projects, like recovering erased text from ancient manuscripts using spectral imaging and image processing.

And in the future, I see my work focusing on the nexus between remote sensing science and humanitarian policy. Earth imaging has already proven crucial in response to natural disasters. My hope in the future is that we can do a step better – and actually predict and prepare for preventable, slow-onset global crises (e.g., food shortage) in the developing world.

How can you make grad school work for you?

I went to RIT (also Imaging Science) as an undergraduate and continued on in the PhD program. As a new grad student it’s invaluable to get to know your classmates, professors, and staff. Become part of the group. A great strength of many higher education programs is the huge diversity of students, backgrounds, and experiences. Often we tend to stick to the familiar, but go outside your comfort zone! Get to know each other, work together, and learn from each other!

Finally, the degree is yours to create!


Learn more about a degree from RIT’s Center for Imaging Science by visiting their profile on GradSchoolShopper.com.

The author, David Kelbe, is a National Science Foundation Graduate Research Fellow, researching airborne small footprint waveform lidar (light detection and ranging) for his dissertation. He has also worked on uncovering erased text from ancient manuscripts, and manages to find time for not one but two local community service projects: Kelbe volunteers at a refugee outreach center as well as a men’s emergency homeless shelter, both in Rochester.

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Original Source: GradSchoolShopper.com

Young Stars Reveal Their Secrets in Rochester Backyard
Student Stories
Graduate
Astronomy and Space Science

What are we really looking at when we gaze up at the stars in the night sky? That is the question that inspired RIT graduate student Billy Vazquez to build his own backyard observatory. He has now added a spectrograph to the available instrumentation at what Vazquez has dubbed the “Vazquez Astronomical Observatory” (VAO) thanks to a microgrant he received from RIT’s Chester F. Carlson Center for Imaging Science. 

Feb. 10, 2014
Lisa Powell


© Billy Vazquez

Vazquez studies stars and galaxies visible from western New York by taking optical images with a camera attached to his telescope. Those photographic images, however, portray only what we would see with our eyes if we stared through the telescope long enough.  

A spectrograph enables astronomers to capture spectra of the same stars and galaxies seen in telescopic photos. Spectra show the intensities of the different wavelengths of light, just as a ray of light is broken into colors after it has passed through a prism. By using a spectrograph to examine the light that comes from a star or anything else that shines out in the universe, Vazquez and his team get deeper insight into these celestial objects. "We get an incredible amount of information from those spectra."

"If you want to see what a person is made up of inside you take an X-Ray image. That is sort of what a spectrograph does. I attach the spectrograph to my telescope and point it to a star, and that enables me to study the elements within the atmosphere of a star. "

Vazquez is particularly interested in young stars -- stars that have lived a very short time relative to the Sun, which has been burning hydrogen in its core for the last 4.5 billion years. Astronomers look for what Vazquez calls the signatures of youth in stars. For example, the presence of dust around a star is one possible indication of cosmic youth. 

Stars form when a cloud of interstellar gas and dust, mainly composed of molecular hydrogen, begins to collapse. Over million of years, gravity compresses the cloud. As it gains gravitational energy, it will heat up and radiate it away, becoming a “protostar”. Eventually, the core of the protostar begins to fuse hydrogen. Such a newborn star is often obscured to optical light because of the dense dust cloud still surrounding it, so newborn stars are difficult to detect with optical telescopes. Eventually winds from the star blow the surrounding cloud away, like the ocean wind blowing fog off a beach. The young star, if close enough to our solar system, then may become visible through a backyard telescope.

If Vazquez has data suggesting that he is looking at such a young star – for example, because the star is known to be “dusty”, or is known to emit strongly in X-rays -- he  then uses the spectrograph to help seek the presence of lithium in the star's chemical makeup. Lithium is an element that is quickly destroyed when a star’s core heats up, and thus it is used as a tracer element for a recently born star. If Vazquez discovers lithium in the spectral information in conjunction with X-ray and infrared excess then he has strong evidence that the star is young, perhaps 'only' ten to a hundred million years old.

Vazquez uses his telescope to assist the Center for Imaging Science faculty member Dr. Joel Kastner in his research on young stars. "My telescope does not reach too far into the Universe but I can still observe lots of stars, even with its 12-inch aperture." This aperture is much less than the diameter of professional telescopes, which can go much farther into the universe and measure the light from galaxies and stars that are much dimmer and harder to find. But, Vazquez says, "from suburban Rochester I can help Dr. Kastner –along with his collaborators around the world--find what they need to see. We can be of some use with this little backyard telescope; it saves time and money and there is no competition for telescope time!"

How far does Billy Vazquez plan to travel from suburban Rochester and the VAO?

"I have family here. I am in my mid-forties and have three kids and my wife works for Xerox, so I don't have plans to go anywhere. My goal is to teach at the college level if possible and continue my outreach work with the community here."

You can see images and read more about the VAO at Vasquez's blog:

http://billyvazquez.blogspot.com/

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East Aurora Resident Images Artifacts at Boston Public Library
Student Stories
Undergraduate
Innovative Freshmen Experience

RIT undergraduate student Maggie Castle wins grant to fund project, leads team of students

Jun. 16, 2011
Susan Gawlowicz

East Aurora resident Maggie Castle (above center) recently led a team of imaging science students from Rochester Institute of Technology on an expedition to the Boston Public Library to test an imaging device they designed and built over the course of their freshman year.

Castle, the daughter of Dan and Kathy Castle of East Aurora, will enter her second year at RIT’s Chester F. Carlson Center for Imaging Science this fall.

As a student in the Freshman Imaging Project, Castle won a $3,000 grant from the Carlson Center to test the imaging device she and her classmates designed and built during the yearlong foundation course.

The device, measuring two feet in diameter, makes polynomial texture maps, or PTMs, using visible light. Typically custom-made, the tool aids professionals working with historical documents and artifacts. The dome-shaped contraption Castle’s class built is covered with 23 LED lights that illuminate an object from multiple directions and angles. Software written by Castle’s classmates compiles 25 to 40 shots into one interactive image to reveal subtle surface textures and features, such as dents, cracks and underwriting.

Castle and her team took the device on the road to the Boston Public Library, where RIT alumnus Tom Blake works in the Digital Lab. It was an ideal venue for trying out the device. Activity in the lab focuses on digitizing books and artifacts for public use and to make available on the Internet, Castle explains.

“Our main goal was to take polynomial texture maps of many of the artifacts and historical documents Tom provided us with to see what worked and what didn’t with our device, and how we might improve it in the future,” Castle says.

Blake brought the students a sampler platter of artifacts to image, including ancient cuneiform tablets, the original masthead of The Liberator newspaper, a Mongolian prayer board, two death masks and a page of the Gutenberg Bible.

“It was an awesome experience to be working with such amazing artifacts,” Castle says. “Not everyone gets to hold a real cuneiform tablet in their hands or see the death masks of Sacco and Vanzetti up close.

“Many of the objects that we took PTMs of had a lot of great texture, which made for great PTMs,” Castle says. “You can’t show a PTM with a picture,” Castle says. “It is an interactive image, not a still one. Tom Blake was really excited about the PTMs we created for him because he wants to show his colleagues that there are more ways to digitize and document the artifacts in the library besides just a still picture.”

Castle hopes to publish an article about the experience in an undergraduate research journal. Her team includes RIT imaging science students Kevin Dickey, Scarlett Montanaro and Dan Goldberg.

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Motion Picture Science Students Bring Their 3D Vision to RIT
Student Stories
Undergraduate
Motion Picture Science

It’s a simple story of supply and demand, or demand and supply, depending on how you look at it. In any case, what began as a quest for a senior project emerged as a useful legacy created by students, for students.

May. 24, 2011
Amy Mednick

Ian Krassner and Allison Hettinger, students of Professor David Long, are newly graduated from the Motion Picture Science program at the College of Imaging Arts and Sciences. The Motion Picture Science program is a collaboration between the School of Film and Animation and the Chester F. Carlson Center for Imaging Science. By joining a core curriculum in practical film-making from the College of Imaging Arts and Sciences and imaging science from the College of Science, this program trains students in the art and science of feature film, television, and animation production.


Motion Picture Science senior Allison Hettinger with the 3D projection setup

Krassner and Hettinger knew School of Film and Animation students lacked the expensive equipment necessary to produce stereoscopic, three-dimensional motion pictures. And so, for their senior project, the two graduating students set about to find a successful, yet economical, approach to enable SoFA film majors to shoot, edit, and screen a convincing and enjoyable digital movie that creates an illusion of depth perception.

“We wanted to create a way for the film students to create 3D movies, from filming, to editing, to viewing,” Hettinger says. “Our project will also help educate the film students in how to make good 3D versus bad 3D movies.”

 

Initially, the two seniors created a rig built specifically to mount two Canon digital video cameras that are readily available for any film student. They conducted two shoots with their newly designed rig, taking both qualitative and quantitative test scenes.


Motion Picture Science senior Ian Krassner demonstrating the 3D camera rig

In order to edit the footage, Hettinger and Krassner took the simplest route and used the Final Cut Pro software available in the film school computer lab. Then, through many hours of trial and error, they found a way to view the footage in anaglyph—images that provide a stereoscopic 3D effect—on the computer to allow students to edit in 2D or 3D.

To view the 3D clips, they set up a rig with dual projectors and polarized lenses. They tested many sets of images on the silver screen, which they bought with a portion of the $2,000 in seed money provided by the CIAS. In the course of developing this complex workflow on a budget, Krassner and Hettinger gained a better understanding of the pivotal concepts under debate in the industry concerning good vs. bad quality 3D filmmaking.

One of the biggest unexpected challenges, both students say, involved discussions around budget issues, equipment purchases, and waiting for deliveries. “It’s the real-life learning about working with time, space, and budget limitations, while choosing when to maneuver around unforeseen roadblocks and when we needed to just tackle the problems head on,” Krassner says.

While their results to date are not quite at the level of the 3D version of Avatar, the legacy is real at CIAS. Next year’s seniors are already designing their own projects piggybacking on this year’s work. Future students will be able to borrow the 3D film equipment along with a book of guidelines authored by Hettinger and Krassner. 

“You know it works when the film students see what they’re doing and want to get their hands on it,” Long says.

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RIT Sponsored Research garners $52.7 million in funding
General

Portfolio up 12 percent; records for new awards, proposals and number of investigators

Nov. 10, 2014
Ellen Rosen

Rochester Institute of Technology’s sponsored research portfolio grew by 12 percent in fiscal year 2014, reaching $52.7 million in funding.

RIT received a record 410 new awards in the fiscal year 2014 from a variety of state, federal, corporate and foundation sponsors. Half the funding came from federal sources, with the National Science Foundation alone providing $11 million in funding, up from $7.4 million the previous year.

“This is an indicator of how RIT continues to mature as a research university,” said Ryne Raffaelle, RIT vice president of research and associate provost. “I am encouraged by how our research portfolio has evolved in new areas such as health-related technology and computing and information security as we continue to grow some of our traditional areas such as sustainability and imaging science.”

The success comes as RIT is on the verge of moving into the national research category as assigned by the Carnegie Foundation, which U.S. News & World Report uses to classify universities. National research classification is based on the number of Ph.D. degrees awarded. RIT had a record 29 graduates earn their doctorates this past spring. A doctoral program in engineering began this fall, becoming RIT’s seventh Ph.D. program and joining astrophysics, color science, computing and information sciences, microsystems engineering, imaging science and sustainability.

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Original Source: University News

JARS article by CIS Research Faculty one of the most downloaded in 2014
Faculty/Staff
Remote Sensing

Article authored by Aaron Gerace and John Schott named by the Journal of Applied Remote Sensing as one of the most popular in 2014

Oct. 2, 2014

Journal of Applied Remote Sensing

Downloads of JARS articles also continue to rise, with articles published in 2013 having an average of more than 600 downloads since publication. The articles with the highest number of downloads in 2014 are listed below.

JNP is accessible to a large international user base via the SPIE Digital Library and is indexed in Web of Science/Science Citation Index Expanded (SCI-E), Scopus, Inspec, Current Contents, and other key scientific databases.

 
Most-downloaded JARS Articles in 2014:

Increased potential to monitor water quality in the near-shore environment with Landsat’s next-generation satellite: Aaron D. Gerace; John R. Schott; Robert Nevins

 

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Original Source: Journal of Applied Remote Sensing

Making Hidden fonts visible
Cultural Artifact and Document Imaging
Graduate
Alumni

News article in Austrian national daily newspaper der Standard about manuscript imaging in Vienna, with a processed image by Imaging Science BS graduate and current PhD student Dave Kelbe

Oct. 29, 2014
Kurt de Swaaf

The book pages are irradiated with light of different wavelengths.  Because parchment and ink varies strongly absorb this light, the hidden font will be exposed.At left: The book pages are irradiated with light of different wavelengths. Because parchment and ink varies strongly absorb this light, the hidden font will be exposed.

Photo: spectral imaging by the Early Manuscripts Electronic Library. Processed image by David Kelbe. © project fwf p24523-g19

*This article is translated from German. Please excuse any translation errors.*

 

Quasi invisible ancient writings, the store in the Austrian National Library, give thanks to modern technology reveal their secrets

Vienna - Konstantin Opel in the 16th century: Ogier de Busbecq is Imperial as an official envoy of His Highness Ferdinand the First stationed in the capital of the former Ottoman Empire. But the interest of the Flemish nobleman is not only his diplomatic mission. "He was an avid collector handwriting," said the philologist Jana Grusková.

The Bosporus metropolis provides for the bibliophile Ambassador is a very interesting hunting ground. Over the years, acquired de Busbecq more precious tomes, so books in the format of a half sheet. Including a bound collection of ecclesiastical decrees from the 10th century. Later, he bequeathed these works of the Viennese Court Library. The book mentioned above is cataloged sometime under the title "Codex Vindobonensis historicus gr. 73" and disappears on the shelves.

The Sleeping Beauty takes about 400 years. Then start several scientists, the holdings of the Austrian National Library to search systematically for so-called palimpsests.These are books and music from multi-described parchment.The writing material made ​​from tanned animal skin was expensive and was often used in the Middle Ages several times. But one scraped from the ink of the original font, to again existed a blank sheet.

But often, the memory of the first text received - a potential treasure trove for scholars. To make the font remains readable again, researchers used in the 18th and 19th centuries, various tinctures, as Grusková reported. However, these chemicals also deployed a destructive effect: So the text was indeed decode and write the content, but the manuscript itself was slightly lost for posterity.

Modern technology has since been ready much more elegant solutions. Grusková, who works at the Austrian Academy of Sciences in Vienna, is currently working together with their colleagues Gunther Martin of the University of Bern in mind, the "Codex Vindobonensis historicus gr. 73" to elicit its secrets. The Austrian Science Fund FWF funded the project.The band eleven palimpsestrierte leaves were added in the 13th century at the end. On them monks monastic rules and prayers were written.

The parchment sheets originally come from two different manuscripts from the 11th century. Their text fragments were indeed discovered decades ago, but they were not using the UV light still frequently used read carefully. Too weak were the ink traces.

Let there be light

A collaboration with American experts has now brought the breakthrough. The technical team of the Early Manuscripts Electronic Library (EMEL), a research organization based in Los Angeles, traveled to Vienna with his equipment and sat there a newly developed multi-spectral method. In this case, the sheets are irradiated with light of different wavelengths.Each is absorbed to different degrees of parchment and ink.

The degree of absorption can be noted on specific photographs. The scientists then add the images in the computer together and get so amazingly detailed illustration of the hidden font. The readability of the text has been increased from 15 to 60 percent, says Jana Grusková. Now open up whole sentences and the content.

Most of the palimpsests of the Codex contains reports on the lives of saints. Particularly interesting are the last two double sheets: You seem a copy of Scythica to be taken by the Greek historian Dexippus of Athens. A small sensation.Because so far were of this work only quotes and transmitted clippings known.

Dexippus lived in the 3rd century AD. In the Scythica he describes how his time come Gothic tribes on the southern Balkan Peninsula. Today Greece and the areas north of it were under the Roman Empire at that time. The invaders left devastation. Several cities were sacked, including Thessaloniki and Athens.

Reports of resistance

The history of these campaigns is considered to be poorly documented. There has been no detailed representations of witnesses. The Wiener palimpsests but can obviously close some gaps in knowledge. The Dexippus attributed both texts report on the invasion by a Gothic army led by Prince Cniva during the years 250/251 and 267/268 on the so-called Herulereinfälle. The first fragment included a certain Ostrogotia is mentioned. He was probably a Gothic chieftain and was already surfaced in other, later writings. "Many say that was an invention," says Gunther Martin. "We now have a contemporary source that confirms that a man of that name really exists."

The second part of the text contains a more important and hitherto unknown facet. The chronicler reports on the collective resistance of Hellenic troops from different cities.They had the advancing Goths, here called Heruli, contrasted together at Thermopylae - where the country was 687 years before that defends against the Persians. Dexippus, the Greeks represent a unity, but what they were not, as Martin says. "It conjures up the Hellenism." However, the command had a Roman official.

For a fascinating detail, the researchers did not need technology: A prominent previous owner of the tape purchased by de Busbecq, Theodosius IV, Patriarch of Antioch, has left on the last page of a warning to potential thieves. "The one who alienates these Codex, may the indissoluble excommunication by the Father, the Son and the Holy Spirit subject and suffer the fate of the traitor Judas. " No question, the man loved his books. (Kurt de Swaaf, THE STANDARD, 10/29/2014)

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Original Source: der Standard

Landsat Ghostbusters—How the Landsat Calibration Team Caught a Ghost
Faculty/Staff
Alumni
Remote Sensing

Oct. 31, 2014

A Landsat thermal image with banding

Shortly after the launch of Landsat 8, the calibration team noticed something strange: bright and dark stripes, or “banding” was showing up across certain images collected by the satellite’s Thermal Infrared Sensor (TIRS). Prelaunch testing of the sensor had indicated that highly accurate measurements (within 1 Kelvin) with little “noise” could be expected—what was going on?

Then, when Landsat 8 collected data as it under flew its predecessor, Landsat 7, en route to its home orbit, thermal measurements of the same region of Earth taken at the same time by the two satellites—which should have been the same—showed several degrees of error.

Something was definitely wrong.

To solve this mystery, the Landsat calibration scientists had to look for clues.

Above right: A TIRS (band 11) image over Los Angeles and the Pacific Ocean showing significant “banding.” Image credit: Schott et al., 2014

Clue #1—Near & Far
The Landsat calibration scientists, or cal team, next compared the radiance measurements made by the TIRS instrument to ground-based measurements made from lake-based buoys. This process of comparing satellite measurements to “ground truth” is called absolute calibration.

The absolute calibration verified that there were significant errors for certain scenes that were severe enough to violate Landsat’s rigorous quality requirements.

Oddly, while errors were detected in TIRS’ thermal measurements of the ground, internal calibration measurements (measurements of an onboard light source called a “blackbody”) were good.

In fact, looking at just the onboard calibration, TIRS was exceeding its performance requirements for both noise and stability.

“The calibration results from the onboard blackbody indicate that the instrument is extremely stable. The absolute calibration data was giving us comparatively huge errors; that doesn’t square with an instrument that looks to be rock solid,” calibration scientist Julia Barsi explains.

This discrepancy told the cal team that when the telescope was looking at a uniform source of energy that filled the telescope’s field-of-view, the problem disappeared.
 
 
Clue #2—Overlap

Banding over Lake Superior

A TIRS image of Lake Superior, with the three different SCA contributions shown. Notices the banding at the SCA borders at positions 1–4. Image credit: J. Barsi

The TIRS instrument uses a new focal plane technology to detect thermal radiance called Quantum Well Infrared Photodetectors, or QWIPs. It takes three staggered QWIPS to cover Landsat’s 185-meter swath width (each of these QWIP modules are referred to as Sub Chip Assemblies, or SCAs.)

The center SCA overlaps with portions of the right and left SCAs. In the places of overlap, coincident measurements of the same ground location are made—and should measure the same radiance. But in some cases their measurements drift apart causing that “banding” that first alerted the cal team to a problem.

The cal team ran tests to make sure the environmental conditions aboard the satellite were stable and that varying temperatures on the focal plane were not causing the problem. The focal plane needs to be uniformly cooled to less than 40 K (-388º F), while the telescope optics need to operate at 186 K (-125º F).

Conditions proved stable.

So now the cal team knew the instrument’s operating environment was not the problem and that the errors were not being caused by any internal instability.

 
Clue #3—Hot & Cold, Time & Place
In scenes that showed both desert and sea, the cal team noticed that the SCA overlap differences seemed to loosely correlate with the transition from hot land to cool sea, and these differences appeared to vary with season—they were worse in the summer. Also, the TIRS image radiance wasalways higher than “ground truth” measurements.

Red Sea Landsat image with Banding

A TIRS (band 11) image of a scene over the Red Sea (left) and a context map from USGS Earth Explorer (right). The image data from the three SCA focal plane arrays is evident due to banding in the across track direction. Image credit: Montanaro, et al., 2014.

Given all of these clues, the cal team started to suspect that radiance from outside of the scene might be scattering into the telescope’s field-of-view, making some radiance measurements higher than they should be. This would also explain why the errors were varying—energy from varying places was hitting the detectors as the satellite collected data along its path. And it would explain why the errors were worse in the summer, when the surrounding land and water were warmer.

 

Looking to the Moon for Answers

The ghost signal

At this particular lunar position, a ghost signal appears on both bands in array-A. Image credit: Montanaro et al., 201

To test this stray light theory, the cal team needed a bright, concentrated light target, surrounded by darkness that could be imaged to see if any energy from outside the telescope’s field-of-view showed up in the data before the telescope set its sights on the target.

A signal from an out-of-field source, or a “ghost signal,” could be found this way.

The moon held the answer.

The moon, a bright object surrounded by darkness, was the perfect target. Landsat 8 looks to the moon each month as part of its calibration process.

Lunar scan data confirmed that light from the moon was showing up in the data before the moon was in the telescope’s field-of-view.

The cal team had found a ghost.

 
 

Putting it Together

ghost source

The on-the-ground ghost source. The blue box in the center shows where the Landsat scene is relative to the ghost source (the blue semi-ring shape). Image credit: Montanaro et al., 2014

The cal team had confirmed that stray light (i.e., the “ghost signal”) was causing the errors they were seeing.

“The error in bias was a direct result of the stray light, since more radiance was getting to the focal plane than should be.” Barsi says.

The ghost signal has added as much as 8 K to data readings for the second TIRS thermal band, or band 11. Band 11 errors are typically double those of TIRS’ first thermal band, band 10.

 
 

 

 

Finding the Ghost-maker

TIRS diagram

The retaining ring on the third lens was found to be the ghost-maker. Image credit: TIRS optics team

After an especially designed lunar scan, the TIRS optics team (the team that built the instrument) used reverse ray tracing to find the surface within the TIRS instrument that was causing the out-of-field reflections as well as the source regions “on the ground” that the errant surface was reflecting.

A retaining ring for the third TIRS lens was found to be the errant reflective surface in the instrument. This piece of hardware that keeps the third TIRS lens in place was also reflecting unwanted energy onto the focal plane.

The ghost-maker had been found.

The lunar scan together with the ray tracing also identified the out-of-field regions on the ground that the retaining ring was reflecting.

 

Ghostbusting

Cal team

Some of the Landsat cal team members, i.e. the Landsat Ghostbusters. Image credit: Nina Raqueno

Getting rid of the TIRS ghost to fix the data is no small undertaking.

After the discovery of where on the ground the extra signal is coming from, the cal team can now calculate what the contribution of that extra signal is, and then subtract that from the TIRS measurements to get the accurate answer.

Since the place on the ground where the extra signal is coming from is outside of the Landsat scene, the cal team needs to use coincident data collected by a satellite with a broader field-of-view. Currently they are using data from a geostationary weather satellite (GOES) to figure out the radiance measurements coming from out-of-field and feeding that into their calculations. This involves accounting for the different orbitology, geometry, and sampling of the wide field-of-view satellite and Landsat.

And these calculations need to be made for each TIRS detector—all 2000 of them.

It’s good to have a crack cal team.

Cal team member John Schott said that the solution the cal team is now working on will be tested this winter and spring. Once the team is satisfied with their results, the methodology will be implemented by USGS into their Landsat 8 ground processing system. Once the cal team delivers the solution, the implementation process will take about a year to implement. For now,USGS advises to only use TIRS band 10 for thermal measurements.

 
 
References:

John R. Schott, Aaron Gerace, Nina Raqueno, Emmett Ientilucci, Rolando Raqueno, Allen W. Lunsford, (2014). Chasing the TIRS ghosts: Calibrating the Landsat 8 Thermal Bands. Proc. of SPIE: Earth Observing Systems XIX,v. 9218,

Matthew Montanaro, Aaron Gerace, Allen Lunsford, Dennis Reuter, (2014). Stray Light Artifacts in Imagery from the Landsat 8 Thermal Infrared Sensor. Remote Sens.,v. 6, no. 11, p. 10435-10456.

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Original Source: NASA Landsat Science

Imaging Science Undergraduates Tackle Ambitious Summer Research Projects
Undergraduate
Student Stories
Color Science

Aug. 9, 2011
Amy Mednick

On the exterior it seems Brick City is sweltering and sleepy this summer, but expectations are high and real-life research is steaming along for two undergraduates in Professor Jinwei Gu’s color science labs. Students Kevin Dickey (below left) and George Huaijin Chen are steeped in the scientific method as they tackle research projects that they will present at the 20th Annual Summer Undergraduate Research & Innovation Symposium on August 12th.  

 

 

 

 

 

 

Sophomore Kevin Dickey has set an ambitious summer goal of creating an inexpensive, hand-held material classifier, or “gloss meter,” initially hoping to use LEDs (light-emitting diodes) as sensors. In his research, the sophomore from Peoria, Illinois has taken on the life of an imaging scientist and truly embraced the scientific method. Dickey has researched, ordered, and tested LEDs, graphed their performance, and written up pages and pages of data and results concerning the ins and outs of using the devices as sensors. (You can follow Dickey’s progress at http://led-brdf.wikispaces.com.)

Dickey is building an inexpensive version of a device normally costing around $5,000 that will classify the surface gloss of, for example, a countertop or a wall. Dickey envisions a hemispherical device armed with LEDs to sense the object and then transmit the information to a software program that will produce a graph describing the material. He has tried white LEDs, red LEDs, expensive and inexpensive models. His original purchase of several low quality LEDs at Radio Shack actually yielded good results, but two identical LEDs could not sense each other’s specific wavelength of light, a critical criterion for Dickey’s instrument. In other words, the LEDs worked perfectly for the average consumer, but not for an undergraduate researcher.

In the process, however, Dickey has learned the basics of circuitry and refined his knowledge of coding, and he is communicating his progress on a daily basis. Most recently, Dickey realized that because modern LEDs are now used so commonly in all kinds of lighting , there is no need for them to function well as sensors. Instead, Dickey says, he has decided to turn to phototransistors, which are inexpensive, fast, and similar in size to LEDs. “The physical dimensions are especially important because a sensor that is round and shaped like an LED will allow for easier mounting within the final gloss measurement device,” Dickey says. “I’m currently testing a new set of phototransistors as we speak, expecting some good results. They are, after all, designed to sense light!” There is hope, after all, for Dickey’s inexpensive material classifier.

Chen—a double major in Management Information Systems and Imaging Science from Shenzen, China—received  $3,000 in support from the Summer Honors Program to design a system that solves the problem of false exposure in digital cameras. This adaptive, programmable camera system allows Chen to control the shutter of the camera at the level of an individual pixel with the goal of producing more detailed images and, eventually, improved color. Most conventional digital cameras with a single aperture have limited dynamic range, which makes it difficult to preserve the same details in the bright and dark areas of a potential shot. In order to capture high dynamic range (HDR) images, current technology forces photographers to shoot multiple images of the same subject. And, if the subject is moving, this method doesn’t even work. To explore new methods, Chen is using an LCD monitor without a backlight to control the transparency of each pixel. Chen has used the program MATLAB to create a code in which each pixel has a unique exposure. Chen’s software program will give him the ability to increase the amount of light that is hitting an underexposed area on the sensor, while blocking light on an overexposed area, thereby preserving details in both bright and darks areas of the image. His system is now a working prototype, complete with a platform for the LCD modulator built from LEGO bricks.

“The future goal of this system is to enhance the color range of the camera,” Chen says. He plans to continue this work as his senior project. Will we see this technology at Best Buy in the next five years? “It's hard to say,” Chen says. “It usually takes years for new technologies to go from lab to market. We will try our best."

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CIS Undergraduate Sleuths Origins of Historic Documents at Library of Congress
Undergraduate
Student Stories
Cultural Artifact and Document Imaging

Nov. 16, 2012
Amy Mednick

Most undergraduates do not get to experience a summer working alongside Library of Congress preservation experts and curators in preserving 500-year-old documents. Chester F. Carlson Center for Imaging Science junior Maggie Castle got that opportunity. For nine weeks last summer, Castle worked on a diary from the mid-15th century and a 1513 Ptolemy atlas that few people ever see, let alone examine in great detail.

During Castle’s Freshman Imaging Project, the students created a polynomial texture mapping device, which allows imaging scientists to study the texture of an old document.  Dr. Fenella France, chief of the Preservation Research and Testing Division at the Library, was invited to speak to the class and Castle became intrigued by her work. Later, she visited France’s lab during a vacation to Washington, D.C.

Inspired by her visit, Castle applied for and received an internship in the Preservation and Testing Division at the Library of Congress in Washington, D.C. to work on three separate projects using spectral imaging at ultra violet, visible, and near-infrared wavelengths. CIS Professor Roger Easton agreed to fund the internship last summer.

“Maggie's interest was fortuitously timed, as I had spent the summer of 2011 at the Library helping to develop some of the techniques used to process the imagery,” Easton said. “The value of such an opportunity to an undergraduate student is incalculable, and she will find that the techniques she utilized are applicable in a wide range of disciplines, including medicine and environmental remote sensing."

Initially, Castle delved into assisting experts in figuring out the origins of the nautical diary of 15th century German mathematician and astronomer Johannes Müller von Königsberg (1436-1476), known as Regiomontanus. The diary consisted of a collection of astronomical calculations and sketches that paved the way for the transition from the Julian calendar to the Gregorian calendar, which we presently use, in 1582. Castle used spectral imaging to extract watermarks in an effort to determine where and when it was printed. She found four watermarks and “hidden text” on six of the 15 imaged pages.

“The challenge was there was a lot of guess and check work,” Castle says. “After using the software, you had to experiment with different bands to try to get the watermark to pop out and visually discern it from the background.”

For her second project, part of an effort to preserve the diary and other documents from the same time period, Castle was charged with investigating the reactivity of iron gall ink, also using spectral imaging. This would help preservation scientists select a method to assess treatments for stabilizing ink on historic documents. Iron gall ink, made from iron salts and tannic acids, was common during this time period up to the 20th century. Iron (II) sulfate heptahydrate, contained in the ink, is corrosive to paper. Castle was able to figure out, using a spot test, the percentage of reactive Iron(II) in test prints to create plots depicting the change in this percentage over time for various preservation methods.

Finally, Castle had the extraordinary experience of working with a 1513 edition of the Ptolemy Atlas, one of three copies of this rare book published by Johannes Schott in Strasbourg. The goal was to figure out which pigments had been used in hand-coloring the map. Once again, spectral imaging allowed Castle to examine the document non-invasively and to separate the image set into a set of spectra that can help determine the mixture of pigments at point (pixel) on the image. She then compared these spectral curves and compared them to existing pigment samples. In the final weeks of the internship, Castle discovered that fustic, a yellow, might have been used.

”Maggie Castle showed great enthusiasm for her work in the Preservation Research and Testing Division, and a true appreciation for the uniqueness and importance of these rare collection items at the Library,” Dr. France said. “Many people ask what is the most challenging part of what we do, and I often answer, that there is no room for mistakes; objects we are working with are often the only copy remaining in the world. Maggie’s background in imaging science provided an excellent grounding for the work we do here at the Library, and we were delighted to have her as part of our preservation team over summer.”

While Buffalo native Castle wouldn’t mind returning to Washington D.C., where her sister lives, she needs to buckle down and work on her senior project next summer. 

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