 Hi, my name is Mark Helmlinger from the Imaging Spectroscopy Group at JPL. We're very fortunate to work as an electro-optical engineer there. Our group builds remote sensing instruments, and that's what I'm standing in front of are posters of examples of some of our data that we've collected. Our instruments have been sent on interplanetary missions and around the earth and around the earth in airplanes, and I'm fortunate to be able to travel with those instruments and operate them. In fact, I was in the airplane when this data set was collected, and these data sets are of Death Valley. Our sensor is about as close to a Star Trek sensor package as you might find. We can mount it in all sorts of platforms and airplanes, a platform, a remote sensing platform, and our imaging spectroscopy can be used. Spectroscopy is a very powerful tool, and it can be used to make maps of the surface chemistry of planets or the earth. For Death Valley, for example, this is what we call a RGB image, or a true color image, which you'd see if you were looking out the bottom of the plane, and then this is a false color image made from other spectral bands. So I said this was a RGB image, and this is an RGB image here, and these are other spectral bands. All these colors, every one of these different colors here that I've represented on these posters, is a different chemistry, surface chemistry, different mineral type, different amount of water saturation, all kinds of things can be sensed with this kind of technology. And over here are examples of the types of information that's collected. These are called spectra, or spectrum. So I said this was an RGB image here and here, right? Well, really, your eye can only see red, green, and blue. In a video camera, there's an array of little squares, and each square has a filter over it, or either a red, green, or blue filter over it. And that corresponds to the red, green, or blue response of your eye. And then, if you were to take a magnifying glass to the display you're probably looking at right now, you'd blow it up enough, you'd see little red, green, and blue dots, and it's the combined intensity of those dots that fake your brain out into thinking that's where all the other colors are. So that's an extraordinary claim, and an extraordinary claim demands, extraordinary proof. So what I've made here is what's called an integrating sphere. This is a cake mold from Michael's. It comes in two halves, and it's about the volume of one box of cake mix, and you can make a soccer ball cake with it, or a baseball cake. And it's actually hollow, and I've painted it flat white inside. And I've got three LEDs mounted to illuminate the interior. I have a red LED, I have a green LED, and I have a blue LED. Now, if I turn them all on at the same time, and adjust them just right, that looks kind of like white white, right? But if you look inside, I hope you can see, yes? There's just a red, a green, and a blue LED in there. That's all. There's no white light bulb, so where's the white light coming from? Now, I'm going to do something really interesting. I'm going to turn off the blue one. Isn't that a pretty color yellow? So if we tip it again, you'll see there's only red and a green LED in there. So where's the yellow light coming from? Well, your brain knows that it can only see red, green, and blue, and that yellow is in between red and green in the rainbow. So whenever your brain sees even amounts of red and green light, it says, ah, that might be yellow, even though there may not be actually any yellow light there. You can be fooled. So if I turn down the green light, I get kind of an orange. And if I turn down the red light, I get kind of a chartreuse. And if I turn off the red light and turn on the blue light, well, I can get all kinds of aquamarine shades of blue. And if I turn off the green light and turn on the red light, well, we can get like deep purple and these pinkish colors. So you can see that. Oh, and when you turn all of them on, but you change the blue one, you can do change what's called the apparent color temperature of the light. That means it either looks like it's a white hot filament or a yellow hot filament. So this is, again, it's hollow inside. This is a demonstration tool powered with three batteries, variable resistors and switches. The resistors limit the current to the diodes. It's obviously put together with hot blue out of scrap wood. So knock yourselves out. So we only see those three colors, right? Red, green, and blue. And the dies on these posters are red, green, and blue as well. And we can control the amount of red, green, and blue die on the poster with either channels from these instruments that really are red, green, and blue light or from wavelengths that you can't see called near infrared wavelengths. Now I've made another extraordinary claim that I'm going to demonstrate as well. Near infrared, what's that? It's light you really can't see. So what I've done here is I'm going to generate a rainbow with this overhead projector. If you look, I've got just a slit exposed here on the platen. It's kind of dusty. That goes up, gets focused by a lens and goes in the mirror and it goes through this prism here. And this prism does something that's called spectral dispersion, where it'll take that white light, that bar of white light that is hitting my hand here. And it's going to turn it in to a rainbow because it bends light and it bends blue light more than it does red light. So what I'm going to do to make that a little more obvious, if you'll excuse me, is put up this, this is what we call increasing the contrast ratio. This is blocking some of the light from our ambient illumination. I'm also going to turn off the interior lights here. This should make it a little more obvious. Now dispersion is a mechanical thing. It has to do with the way wavelengths of light interact with different materials, as the waves go through, it's called index of refraction. And I made a claim that there's light you can't see with your eye but yet exists, right? Seeing is not believing, there's a lot more to the universe than you can see with your eye, right? So what I've made here is a radiometer and it has an entrance slit in it and a bar graph, right? And if I expose it to the ambient light, you can see the lights go up and down on it as I let light in and into and out of the detector here. This detector can see wavelengths of light that your eye can't see. It's a silicon solar cell, in fact, one from on top of one of those solar powered daisies. So what I've got here is this is the ambient light kind of lighting up that the detector giving enough. Now here, I don't know if you can see it, but there's this, the rainbow is on, actually shining on the body of the housing of the instrument here. And there's blue, green light going in. See if I put my hand there, it goes off. And so now there's mostly green light or yellow, maybe, right? And then here's some red light, it likes the red light a lot better. There, if I point it the right way, it'll get to the right spots, okay? And then here it is out in the dark where there isn't any visible light, but what do you know? It still responds. Here I can make it more sensitive. There we go. This is called a gain adjustment. So again, here we are in the blue and the green and the red, really likes the red. And then, wow, look at that! There's a lot of something hitting that detector, but you can't see it with your eye. And that's infrared light. In fact, well, let's see how far does it go? Well, there's a lot of infrared, this is the ambient light from the surroundings here, but it starts to pick up right around here. And then it goes back down again, right? So with a spectrometer, it's an optical, and a spectrometer is an optomechanical device. And here we've split up the wavelength of light into its various wavelengths by position here, right? This detector is wavelength agnostic. If the wavelength is between 400 nanometers, which is a measurement, a linear measurement, and 1,000 nanometers, which is the wavelength, a billionth of a meter, this detector will pick it up. But it doesn't care what the wavelength is, it only shows intensity. So it's only by position here that we know what wavelength is actually hitting the detector. And that intensity by wavelength, or by position in a spectrometer, that makes a curvy wiggle, like here. And these curvy wiggles are spectra. And it's like a fingerprint of the light, of the matter that's interactive with the light. Now, our instruments use reflected sunlight, which is basically white, right? It's got a lot of wavelengths in it. But when sunlight hits the ground, goes through the air, it picks up the color of the sky and the color of the air, and it bounces off the ground here, which is done here. It picks up the color of the ground, right? And it hits my shirt, it picks up the color of my shirt, which is reflecting more green light than blue or red light, and so it looks green to your eye. Well, the colors, the colors that you can't see, way out in the infrared, are what our instruments can sense. And by the way, I also have calibrations by specialty, and so showing how to calibrate something is always a lot of fun. This is four LEDs of known wavelength. These are wavelengths that you can actually see with your eye. Remember, that yellow one really is yellow. It's just stimulating both your red and your green cones and the retina of your eye. So, and it's a little shaky in the batteries context. So what I'm going to do is put this, oops, when it works. All right, I'm going to put this right where the slit is. And it's going to, the light from this is going to go up as if it was the slit. And then it's going to hit this board over here. It's going to go through the prism, get dispersed. Now, all those LEDs, trust me, we're in a straight line, about as straight as could be. And yet, if you look real close and your heart is pure, you can see that the red light is, I'm just going to point here, and the red light is in one position, and the yellow light another, and the green light another, and the blue light another. In fact, if you remember, the rainbow was blue here and red there. So because I know the wavelength of each one of these LEDs, if I made them really tiny points and really, really bright, like, oh, I don't know, a laser, right? Now, this isn't working. There we go. So if I actually put a laser through that system, and lasers are very known wavelengths, I'd be able to calibrate it, be able to mark off. Well, that says that wavelength, that wavelength, that wavelength, and I could, with a magic marker here, or a wet board marker, I could make a graph. This is how intense it is, and this is what the wavelength is based on the position. Well, that's exactly what this is. And these are actually number files, files of numbers, just a whole list of numbers, starting at a low wavelength and going to, well, you would call these short wavelengths and long wavelengths here. Now, if you could see, with your eye, if you wanted to know what those wavelengths are, 400 nanometers to 5, 6, 700 nanometers, so the rainbow would fall right in here. So our instrument can see a whole lot of information out here in the near infrared that your eye isn't sensitive to. So what I've done with these posters, for example, this, so that's how we calibrate our imaging spectrometers, by the way. We use known light sources, we shine them into the instrument and see where the light falls, and okay, we know that position is that wavelength. And we do that for several different wavelengths over the entire range of the instrument, and it's calibrated. So for this image here, what we did is chose three colors and three wavelengths of light and controlled the red, green, and blue bands, or dyes in the poster with those three wavelengths. Only one of them is one you can see at about 508 nanometers, which is kind of a reddish, bluish green, I think, 550s green. So in this image, what happens is it so happens that the borax down here in the salt flats of Death Valley come out looking this really bright red. And I'll just point. So if you're a geologist and you want to know, where's that borax coming from? Where's it washing out from? Because Death Valley is a valley and surrounded by mountains. And these structures here are called alluvial fans. They're built up over time as flash floods bring debris out from the mountains and deposit it one way or the other, depending on how it blocks the flow of the water or not. You can see some of these water flows are really, really red. And you'd say, aha, wherever this water came from that made this part of the alluvial fan, that's where in the mountains borax has come from. This kind of information is used by geologists all the time. If you've ever been to Death Valley, bad waters down here, Furnace Creek is here, and the Devil's cornfield is up here. I'm a highly recommend visiting if you've never been. This was a flight that I was fortunate enough to make. We were investigating the air in between the airplane and the ground. We wanted to fly from a high altitude that was close to a low altitude that was far back up to high altitude and Death Valley is a really great place to do that. So what we did is we flew an east-west. This was a north-south transect. This is an east-west transect. We flew basically over Telescope Peak, actually we started up here and went down to Telescope. This is Dante's view. This is the bottom of the valley, bad water, and then to Telescope Peak. So you notice when we make our images with our instrument, our instrument is called a liner array imager. So it works like a scanner, like a platen scanner that you'd scan a document with. We only see one line at a time, but the forward motion of the plane builds up in an image, right? So if things that really are imaging spectrometers sees things in like a fan, so something's close and only sees a little bit of it and something's further away, it sees more of it. But if it's close, the pixels projected are smaller, so your spatial ground resolution is a little higher, it's further away, the pixels are bigger, and your spatial ground resolution is lower. Those are all terminology of the remote sensing business, which is a tool used to study the environment of planets. In this case, the environment of the Earth. So you'll notice it's kind of a narrow here, wide here, and narrow there because of the distance from the plane. The plane flew at a constant altitude over these targets. So what I've done here is I've got these little boxes that you really can't see pointing to various places. Well, each one of these boxes corresponds to one of these boxes here with the spectra in it. And what I've also done is I've used three different bands for each one of these and changed the contrast to just make them look as dramatic as possible, but each one of these colors is actually a different chemical or a plant or a mineral or water or water with stuff in it. And you see by how many gazillions of colors we have here, all kinds of the information that's here, and this is all significant information that gets put into a computer. This type of technology is really good at finding Waldo, for example, whereas you'd have to hire an army of people to stare at pictures, you put this into a computer and boom, you can find exactly that thing that has the chemistry, the apparent chemistry that you're looking for. That's one application. Another application is environmental and looking at plants, whereas up in the mountains here you would imagine there's a lot more plants and they show up as different types. This type of technology can tell the difference between plant types, plant species, and plant health. It can tell the difference between snow, wet snow, dry snow, dirty snow. It can tell the difference between healthy water, ocean water, healthy ocean water, and unhealthy polluted ocean water. It can tell the difference if the water is clear enough and it's shallow enough between dead coral and live coral and coral species. The application is for this technology is tremendous and calibrating it, making sure that it's correct so that we know we can trust the results that we're getting in regards to measuring our environment. I've been fortunate enough to do that my entire career and that's what I was talking about with you here today. And thank you for your attention.