WEBVTT - TechStuff Classic: TechStuff Looks at Night Vision 0:00:04.120 --> 0:00:07.160 Get in touch with technology with tech Stuff from how 0:00:07.200 --> 0:00:13.960 stuff works dot Com. Hei there and welcome to tech Stuff. 0:00:13.960 --> 0:00:16.439 I'm your host, Jonathan Strickland. I'm an executive producer and 0:00:16.480 --> 0:00:19.119 I love all things tech and it is time for 0:00:19.160 --> 0:00:23.920 another classic episode of tech Stuff. This episode originally aired 0:00:23.960 --> 0:00:28.960 on November two thousand eleven. And Chris Pallette, my co 0:00:29.080 --> 0:00:31.479 host and editor at the time, and I decided we 0:00:31.520 --> 0:00:33.479 wanted to take a look at something that's kind of 0:00:33.520 --> 0:00:38.040 hard to see, that is when it's actually being used. 0:00:38.040 --> 0:00:42.520 I'm talking about night vision. How does the technology work? Well, 0:00:42.640 --> 0:00:44.640 Chris and I found out and now you will to 0:00:45.200 --> 0:00:50.360 enjoy this classic episode night Vision. The technology dates back 0:00:50.800 --> 0:00:54.960 to the late thirties early forties. It was technology that 0:00:55.040 --> 0:00:58.520 was developed during World War Two and used mainly by 0:00:58.560 --> 0:01:03.040 the American, British, and and Soviet forces during World War Two, 0:01:03.120 --> 0:01:08.360 although other nations began to to develop their own version 0:01:08.400 --> 0:01:11.240 of night vision technology around the same time. Well, yeah, 0:01:11.240 --> 0:01:14.520 the Germans, Uh, A lot of what we had as 0:01:14.600 --> 0:01:18.080 far as our technology in the United States was based 0:01:18.120 --> 0:01:22.280 on some German research that was done in the late thirties. UM. 0:01:23.000 --> 0:01:27.480 And really what it comes down to, UM is the 0:01:27.520 --> 0:01:31.399 spectrum of light that that you're trying to see. Yeah, 0:01:31.440 --> 0:01:35.600 it's it's two different things. It's trying to accept other 0:01:35.920 --> 0:01:39.240 parts of light that human eye is not able to detect, 0:01:39.319 --> 0:01:44.640 and also to uh to amplify whatever little light is there. 0:01:44.680 --> 0:01:49.200 There are two main ways of achieving a night vision 0:01:50.000 --> 0:01:54.920 UH technology. One is called image enhancement, and that's where 0:01:54.960 --> 0:01:58.000 you're taking the little amount of light that's out there 0:01:58.560 --> 0:02:01.960 and UH and trying to amplify it so that you know, 0:02:02.040 --> 0:02:04.840 you're able to see better in that environment. And the 0:02:04.880 --> 0:02:08.480 other is thermal imaging, which is also you know, we 0:02:08.600 --> 0:02:11.600 think of that as being able to see heat. You know, 0:02:11.639 --> 0:02:14.000 the whole idea about like if you've ever seen that 0:02:14.080 --> 0:02:19.680 documentary Predator, Yeah, the Predator actually uses both forms of this, 0:02:20.480 --> 0:02:22.799 but the thermal imaging would be the one where it 0:02:22.919 --> 0:02:26.000 switches and it's that really colorful display where the hotter 0:02:26.240 --> 0:02:29.120 things in the field of vision are a brighter color, 0:02:29.280 --> 0:02:32.919 usually red, uh, and then the cooler things are are 0:02:33.480 --> 0:02:35.960 in the other part of the spectrum of light, so 0:02:36.000 --> 0:02:38.600 they'd be you know, if it's cold, it might be black, 0:02:38.680 --> 0:02:41.360 but if it's cooler, it might be blue or even 0:02:41.560 --> 0:02:44.840 kind of an indigo color. Um. Both of those are 0:02:44.880 --> 0:02:48.320 ways of achieving night vision. The I think the one 0:02:48.360 --> 0:02:50.360 that most people think of when they think of night 0:02:50.440 --> 0:02:54.720 vision is the one where you've got the greenish uh display. 0:02:54.840 --> 0:02:59.520 That's the image enhancement approach, and well, you know that 0:02:59.520 --> 0:03:02.400 that's I think that's the reason people think about it 0:03:02.440 --> 0:03:06.520 is because it's used that way in TV in the movies. Yeah, 0:03:06.639 --> 0:03:11.760 probably so as a visual clue to the viewer that hey, 0:03:11.800 --> 0:03:15.320 we're doing something that you can't normally do, right, Yeah. 0:03:15.360 --> 0:03:18.160 I In fact, I watched a movie just last night 0:03:18.320 --> 0:03:23.040 that involved having a night vision the screen tinged night vision, 0:03:23.120 --> 0:03:25.200 and it was and I'm not going to call it 0:03:25.240 --> 0:03:28.519 the documentary because that's how much of a skeptic I am. 0:03:28.680 --> 0:03:31.840 It was paranormal activity too, and uh, you know in 0:03:31.880 --> 0:03:36.720 paranormal activity those movies, those are done as found footage movies, which, 0:03:37.040 --> 0:03:39.040 in case you're not familiar with the term, that's the 0:03:39.080 --> 0:03:41.760 idea where the film is presented as if it were 0:03:42.320 --> 0:03:47.800 uh collection of clips taken from various cameras. That it 0:03:47.880 --> 0:03:50.400 wasn't meant to be a feature film. It was supposed 0:03:50.440 --> 0:03:55.120 to be actual footage shot of something, right. So clover 0:03:55.200 --> 0:03:58.760 Field is another example, or Blair Witch Project's another example, Yes, 0:03:58.800 --> 0:04:00.080 that's the first time I thought about. Yeah, and that 0:04:00.160 --> 0:04:03.400 it's really popular with the horror crowd. Uh and uh 0:04:03.600 --> 0:04:07.360 so the paranormal activity too. There's one of the cameras 0:04:07.400 --> 0:04:09.760 that is being used in that has a night vision 0:04:09.760 --> 0:04:13.640 setting and it's using the image enhancement approach. By the way, 0:04:13.640 --> 0:04:18.080 in case you're curious about why green, the the answer 0:04:18.200 --> 0:04:20.800 I found through my research was that the reason why 0:04:20.800 --> 0:04:26.000 you get green images is not because of any technological limitation. 0:04:26.560 --> 0:04:29.280 It's because if you're in an environment where you're using 0:04:29.400 --> 0:04:31.960 night vision, you want to be able to switch between 0:04:32.040 --> 0:04:35.279 night vision and your normal vision as quickly as possible. 0:04:35.480 --> 0:04:38.760 But if you use really intense light and and some 0:04:38.880 --> 0:04:43.240 of the brighter lights, your pupils will constrict as you're 0:04:43.240 --> 0:04:44.960 looking at it, which means when you take the night 0:04:45.040 --> 0:04:47.039 vision glasses off, it's going to take more time for 0:04:47.080 --> 0:04:50.120 your eyes to readjust to the darkness around you. But 0:04:50.200 --> 0:04:52.800 the green that is used is a more subtle light, 0:04:53.200 --> 0:04:57.760 and so your your pupils are remain mostly dilated, so 0:04:57.800 --> 0:05:00.040 when you remove the night vision goggles, you don't of 0:05:00.120 --> 0:05:02.440 as long a time to adjust. It doesn't take as 0:05:02.440 --> 0:05:04.800 long for you to adjust to night regular night vision 0:05:04.960 --> 0:05:09.560 like our natural night vision. Uh when you when you 0:05:09.640 --> 0:05:11.680 go back and forth, and that kind of makes sense 0:05:11.680 --> 0:05:13.599 to me. I mean, if you especially when you consider 0:05:13.680 --> 0:05:18.320 that night vision was really originally used as a military technology, 0:05:18.600 --> 0:05:20.400 you would want to be able to have as much 0:05:20.520 --> 0:05:23.919 versatility and flexibility as possible so that you can adapt 0:05:23.920 --> 0:05:27.200 to whatever the situation calls for. Yeah, that makes absolute 0:05:27.200 --> 0:05:30.120 sense to me. So yeah, so at least according to that, 0:05:30.440 --> 0:05:34.760 we could in theory have night vision where it's any color. Uh. 0:05:34.839 --> 0:05:39.320 You know, it probably still probably be monochromatic, but we'll 0:05:39.320 --> 0:05:40.880 get into that when we get into the you know 0:05:40.920 --> 0:05:44.480 exactly what's happening. So so, all the different kinds of 0:05:44.560 --> 0:05:48.920 night vision lie at least somewhat on the infrared, uh, 0:05:49.200 --> 0:05:52.120 part of the spectrum of light, right, and that infrared 0:05:52.160 --> 0:05:57.000 spectrum of light is outside the range of uh, the 0:05:57.240 --> 0:06:01.160 visible light spectrum. UM. In fact, there are three parts 0:06:01.279 --> 0:06:05.000 to the infrared spectrum, which is near infrared, and that's 0:06:05.040 --> 0:06:09.640 the closest one to the visible spectrum spectrum. Yes, I 0:06:09.680 --> 0:06:13.920 can say that word mid infrared um and that has uh. 0:06:14.160 --> 0:06:17.440 I didn't mention the wavelengths. The wavelengths for near infrared 0:06:17.480 --> 0:06:21.520 are from point seven to one point three microns um. 0:06:21.720 --> 0:06:25.240 Mid infrared has wavelengths from one point three to three 0:06:25.279 --> 0:06:31.240 microns um, and then thermal infrared, which is the biggest 0:06:31.240 --> 0:06:35.000 part of the infrared spectrum, and that's from three to 0:06:35.320 --> 0:06:38.640 more than thirty microns. Yeah, and so the the thermal 0:06:38.720 --> 0:06:46.440 infrared you're talking at that point about infrared radiation really yeah, heat, 0:06:46.839 --> 0:06:49.320 in other words, is what's kind of how we perceive 0:06:49.400 --> 0:06:53.000 it usually. But uh, that's something that's actually given off 0:06:53.120 --> 0:06:57.240 by an object itself, Whereas when we're talking about visible light, 0:06:57.680 --> 0:07:00.760 that's something that's reflected off of an object. Right. So 0:07:01.120 --> 0:07:04.400 if if I'm looking at a tree in sunlight, what 0:07:04.480 --> 0:07:07.320 I'm seeing is the light being reflected off of that tree, 0:07:07.520 --> 0:07:10.440 it's that lights hitting my eyes then going through the 0:07:10.440 --> 0:07:13.720 whole focal point getting into my brain and somewhere up 0:07:13.720 --> 0:07:16.480 there in yeah, somewhere up there in the gray matter, 0:07:16.840 --> 0:07:21.360 my brain says, Hello, there's a tree, possibly a large 0:07:22.760 --> 0:07:27.560 a large. Um. I recognize that from very far away. Yes, 0:07:28.120 --> 0:07:30.760 that's how to recognize trees from very far away, quite 0:07:30.760 --> 0:07:34.240 a long way away. Yeah, So that's how that would 0:07:34.280 --> 0:07:37.760 normally work with thermal infrared. If I were to see 0:07:37.800 --> 0:07:40.640 an object using thermal infrared. Let's say that somehow I 0:07:40.760 --> 0:07:43.400 have that ability. You know, we're not talking about technology here, 0:07:43.400 --> 0:07:47.280 but I somehow have the the the natural ability to 0:07:47.400 --> 0:07:50.000 see the thermal infrared. It happened when they shot him 0:07:50.000 --> 0:07:52.840 into space and he was bombarded by cosmic waves while 0:07:52.840 --> 0:07:56.240 we're really just pop culturing this all to heck and back. 0:07:56.560 --> 0:07:59.200 So yeah, with the thermal infrared ability, I would be 0:07:59.240 --> 0:08:02.440 able to see the energy that is being emitted by 0:08:02.520 --> 0:08:06.800 any particular object. Um it's not necessarily light that's reflecting off. 0:08:06.880 --> 0:08:08.200 In fact, there doesn't have to be any sort of 0:08:08.240 --> 0:08:11.320 light source at all. It just so. And if I 0:08:11.360 --> 0:08:14.400 were in a perfectly dark room and there was another 0:08:15.240 --> 0:08:19.160 object there that's giving off heat, essentially, I would be 0:08:19.200 --> 0:08:21.480 able to see it because I would be seeing in 0:08:21.520 --> 0:08:25.000 that range even though there's no other light source coming in. 0:08:25.120 --> 0:08:29.320 It would just be that I'm actually seeing that that energy. 0:08:29.360 --> 0:08:32.800 Because we'll get into why, it's kind of interesting. Has 0:08:32.840 --> 0:08:39.320 to do with excitation, but not good vibrations. Yeah, although 0:08:39.440 --> 0:08:42.760 perhaps that lady was able. Never mind, So moving on, 0:08:43.600 --> 0:08:46.320 I hope you guys are enjoying this classic episode so far. 0:08:46.480 --> 0:08:48.840 We've got more to talk about, but first, let's take 0:08:48.880 --> 0:08:59.000 a quick break to thank our sponsor. Before we get 0:08:59.040 --> 0:09:01.839 into the whole atoms and thermal infrared, let's let's talk 0:09:01.880 --> 0:09:06.440 about the image enhancement approach first, because that's the one 0:09:06.480 --> 0:09:11.400 that's the most familiar and uh and it's kind of interesting. Um. 0:09:11.440 --> 0:09:15.320 The way that it works currently is that you've got 0:09:15.360 --> 0:09:18.800 you've got very basic parts to a particular kind of 0:09:18.920 --> 0:09:21.200 night vision. You've got you've got your lens. That's where 0:09:21.240 --> 0:09:25.240 the light is going through. The objective lens. Just a 0:09:25.800 --> 0:09:28.719 lens that catches it's a lens. Yeah, it catches ambient light, 0:09:28.840 --> 0:09:32.800 catches near infrared light. So this is the near infrared spectrum, 0:09:32.800 --> 0:09:37.319 the light that's closest to the visible spectrum. Now that 0:09:37.440 --> 0:09:41.080 light is sent to a tube, and that tube is 0:09:41.080 --> 0:09:46.000 called the image intensive fire tube intense. Yeah, and the 0:09:46.160 --> 0:09:48.880 drinking energy drinks all day and yeah. So you can 0:09:48.880 --> 0:09:50.800 think of this tube. It's almost like a vacuum tube. 0:09:50.840 --> 0:09:52.559 In fact, there it is, There is a vacuum in 0:09:52.640 --> 0:09:54.560 side of it. So you think of this sort of 0:09:55.040 --> 0:09:58.560 imagine a glass vial all right in the middle of 0:09:58.559 --> 0:10:01.000 this glass vial or on one end of the class file, 0:10:01.000 --> 0:10:04.280 you've got something called a photo cathode. Now, the photo 0:10:04.360 --> 0:10:09.240 cathode takes photons. Those are those individual elements of energy 0:10:09.320 --> 0:10:12.680 for light. Yes, and and those come in the entire 0:10:12.760 --> 0:10:16.800 spectrum of light um so infrared. They're infrared photons, just 0:10:16.880 --> 0:10:21.600 as there are visible light photons. So the photo cathode 0:10:22.320 --> 0:10:26.640 converts photons into electrons. It's it's one of those. Uh 0:10:26.800 --> 0:10:30.079 So it changes light into electricity essentially. Yeah, And if 0:10:30.080 --> 0:10:32.839 you listen to our episode about high speed and low 0:10:32.840 --> 0:10:38.040 speed photography, we talked about how there are certain types 0:10:38.120 --> 0:10:44.040 of materials that when a photon strikes it, it causes 0:10:44.080 --> 0:10:47.840 a reaction. That's the case here a photocathode. It's that's 0:10:47.880 --> 0:10:50.640 the and that's how it behaves when a photon hits it. 0:10:50.640 --> 0:10:53.560 It gives off an electron. Uh So, You've got the 0:10:53.559 --> 0:10:55.679 photo cathode at one end of this tube, and that's 0:10:55.720 --> 0:10:58.040 where the light that's being captured by the lens is 0:10:58.040 --> 0:11:01.560 directed to the photo cathode. The electrons emitted by the 0:11:01.559 --> 0:11:04.199 photo cathode then have to pass through what is called 0:11:04.280 --> 0:11:09.240 a micro channel plate or m c P. That's a 0:11:09.240 --> 0:11:12.560 little glass disc. Yeah, I see. I thought MCP was 0:11:12.600 --> 0:11:17.840 the master control program. End of line. It is. Okay, However, 0:11:18.000 --> 0:11:20.839 two different mcps well it was until Tron got hold 0:11:20.840 --> 0:11:24.520 of it. That's right. So glass disc Tron m c P. 0:11:25.320 --> 0:11:28.600 I'm sensing some convergence here as we Mentionedron again. Ye. 0:11:28.920 --> 0:11:31.720 So anyway, you've got this glass little tiny glass disc 0:11:31.760 --> 0:11:34.920 called a micro channel plate and has lots and lots 0:11:35.000 --> 0:11:37.480 of channels. That's why it's called a micro channel plate. 0:11:37.520 --> 0:11:40.320 Lots of channels that go through this plate. Okay, So 0:11:40.400 --> 0:11:42.840 think of the plate. Think of it like a dish. 0:11:43.200 --> 0:11:45.520 You got a dish, put it up on its side, 0:11:45.880 --> 0:11:47.720 and it has a whole bunch of little holes drilled 0:11:47.720 --> 0:11:51.080 in it. Now, those holes are what allow electrons to 0:11:51.120 --> 0:11:55.040 pass through. But there's also an electrode on either side 0:11:55.080 --> 0:12:00.000 of the dish. So electrons coming from the photo cathodes 0:12:00.120 --> 0:12:03.760 strike one side of this micro channel plate and start 0:12:03.840 --> 0:12:06.280 to go through one of the channels. And they're going 0:12:06.800 --> 0:12:10.240 through in the same direction they came from the the 0:12:10.240 --> 0:12:15.559 from the photo cathode uh section of this this uh 0:12:15.679 --> 0:12:21.120 this image intensive ire tube. So the photon converts to electron. 0:12:21.160 --> 0:12:23.560 Electron goes through this channel. As it goes through the channel, 0:12:23.840 --> 0:12:30.560 it starts to actually set off a well a reaction. Yeah, 0:12:30.720 --> 0:12:34.559 and it basically functions as a multiplier for the electrons. 0:12:34.559 --> 0:12:38.760 It's called a cascaded secondary emission. So this is where 0:12:38.880 --> 0:12:42.440 when electron collide collides with something inside that that channel, 0:12:42.720 --> 0:12:45.920 it starts to set off other electrons, uh, down that 0:12:46.040 --> 0:12:49.079 same pathway, And there's a voltage applied to those electrodes 0:12:49.080 --> 0:12:52.439 that's channeling the electrons through that pathway, like that's why 0:12:52.480 --> 0:12:56.360 they're going in that direction. So you've got more and 0:12:56.400 --> 0:12:59.880 more electrons bouncing off of each other through these channels, 0:13:00.480 --> 0:13:04.319 which means that you've you've created an amplifier. And uh, 0:13:04.679 --> 0:13:06.800 if you guys want to know kind of like a 0:13:06.880 --> 0:13:10.199 big picture way of what this might look like, imagine 0:13:10.360 --> 0:13:13.680 having a h and you can see play of videos 0:13:13.679 --> 0:13:17.000 of this on YouTube, But imagine having a big glass 0:13:17.000 --> 0:13:20.679 container filled with mouse traps, and each mouse trap has 0:13:20.720 --> 0:13:23.280 a ping pong ball set on it, and then you 0:13:23.360 --> 0:13:27.560 drop a ping pong ball into the glass chamber and 0:13:27.640 --> 0:13:29.960 that will set off a mouse trap, and as the 0:13:29.960 --> 0:13:32.120 ping pong balls bounce around, they set off more and 0:13:32.160 --> 0:13:35.200 more mouse traps, so soon the glass case, like within 0:13:35.240 --> 0:13:39.080 a fraction of a second ball, the balls are bouncing everywhere. Right, 0:13:39.600 --> 0:13:42.040 same sort of idea here with the micro channel plate, 0:13:42.040 --> 0:13:44.800 except that we're talking on a sub atomic level, and 0:13:45.080 --> 0:13:48.839 we're talking about something that's really channeled, really has a 0:13:48.960 --> 0:13:51.960 firm direction. So instead of the electrons bouncing everywhere, they're 0:13:51.960 --> 0:13:55.280 going in a very specific direction. Right now, when they 0:13:55.280 --> 0:13:57.560 get to the other side of that micro channel plate, 0:13:57.840 --> 0:14:00.520 you've got the electrons still traveling in this ame direction 0:14:00.559 --> 0:14:02.480 they were when they came in on the front side, 0:14:02.960 --> 0:14:06.280 but now there are way more electrons, right, just amplified 0:14:06.320 --> 0:14:11.840 the number. The electrons then hit a screen that's coated 0:14:11.880 --> 0:14:16.840 with phosphors. Now phosphors pos phosphors do the they're kind 0:14:16.840 --> 0:14:19.640 of like the opposite of the photo cathode, right. They 0:14:19.680 --> 0:14:22.640 take When the electron strikes the phosphor, they give off light. 0:14:23.280 --> 0:14:26.080 So you're changing the electron back to a photo photon. Right. 0:14:26.120 --> 0:14:29.440 But now, because there are more electrons coming through hitting 0:14:29.440 --> 0:14:32.200 that phosphoor than they were coming in, the light that's 0:14:32.240 --> 0:14:35.960 generated is much greater in intensity than the light that 0:14:36.080 --> 0:14:40.400 was coming in. So you've amplified the light. Now that 0:14:40.760 --> 0:14:44.600 information that light is sent to a viewer of some type. 0:14:44.720 --> 0:14:47.200 It could just be a regular lens, which is usually 0:14:47.240 --> 0:14:50.000 called the ocular lens, or it could be sent to 0:14:50.040 --> 0:14:53.360 a monitor. So if you have a pair of night 0:14:53.440 --> 0:14:57.520 vision goggles or a night vision scope. That's what you're seeing. 0:14:57.560 --> 0:15:01.520 You're seeing that amplified light hitting the lens or the 0:15:01.920 --> 0:15:06.840 Monitor's cool, it's pretty awesome, right, And again, this isn't 0:15:06.960 --> 0:15:10.360 just the the visible light, the ambient visible light that's 0:15:10.400 --> 0:15:14.480 out there, but also the infrared light. So um, because 0:15:14.480 --> 0:15:16.720 those photons, you know it doesn't you know, the photons, 0:15:16.760 --> 0:15:21.040 It doesn't matter if it's visible or not. UM. And uh, 0:15:21.440 --> 0:15:24.680 the more light that's hitting certain areas, that the brighter 0:15:24.720 --> 0:15:27.800 it's going to be for whatever it is you're looking at. 0:15:27.800 --> 0:15:31.480 So if you're looking at something that's that's fairly reflective, um, 0:15:31.560 --> 0:15:35.320 you're gonna be able to see it in higher definition 0:15:35.360 --> 0:15:39.080 than you could with something that is not as reflective. Now, 0:15:39.120 --> 0:15:42.400 there are different ways of actually achieving this too. You 0:15:42.440 --> 0:15:48.720 can have a various they're various generations of this technology, 0:15:48.760 --> 0:15:53.600 all right. So the earliest generation of this technology actually 0:15:53.680 --> 0:15:59.120 involved shining infrared light at the objects you're looking at 0:15:59.200 --> 0:16:02.200 through the through the night vision goggles, right, So when 0:16:02.240 --> 0:16:05.360 that that infrared light was reflected, then you would be 0:16:05.400 --> 0:16:08.880 able to see it, right, because these goggles were not 0:16:09.000 --> 0:16:11.520 so sensitive as to be able to take just the 0:16:11.600 --> 0:16:14.480 ambient light. Right, if you did that, you would probably 0:16:14.480 --> 0:16:17.080 get you you might be able to see marginally better 0:16:17.160 --> 0:16:20.360 than you would if you had just use your regular vision. 0:16:20.760 --> 0:16:26.120 But using this infrared flashlight, essentially you could illuminate the 0:16:27.080 --> 0:16:28.920 scene and be able to see it through the night 0:16:28.960 --> 0:16:31.320 vision goggles. But if you did not have the goggles, 0:16:31.360 --> 0:16:35.760 because infrared light falls outside the visible spectrum, any independent 0:16:35.800 --> 0:16:40.000 observer wouldn't be able to tell what you were doing. Yeah, now, 0:16:40.440 --> 0:16:43.400 I UM I did some research on the the US 0:16:43.800 --> 0:16:49.680 military website about the history of of night vision and apparently, 0:16:50.200 --> 0:16:54.400 um they sent about three hundred sniper scopes over to 0:16:54.440 --> 0:16:56.720 be used in the Pacific theater during World War Two, 0:16:56.720 --> 0:16:59.960 but they didn't get used very much because of the 0:17:00.040 --> 0:17:03.600 way that the technology worked. Um they really could see 0:17:04.119 --> 0:17:07.239 less than a hundred yards. Yeah, they weren't very effective, right, 0:17:07.280 --> 0:17:13.480 because again, since it's dependent upon a reflected ray of 0:17:13.720 --> 0:17:17.080 infrared light, if it's you know, the rays starting to 0:17:17.320 --> 0:17:19.960 dispersees as it goes out, Right, it's not not a 0:17:20.119 --> 0:17:23.000 not a concentrated like a laser beam. Yeah, it's not 0:17:23.040 --> 0:17:26.240 a beam. It does disperse and diffuse as it goes out. 0:17:26.560 --> 0:17:29.840 So the further away your target the less likely you're 0:17:29.880 --> 0:17:32.080 going to be able to see it, and even with 0:17:32.160 --> 0:17:34.359 a really really advanced version. That's, by the way, it's 0:17:34.400 --> 0:17:39.600 called active infrared because you're actively beaming infrared radiation out 0:17:39.680 --> 0:17:43.200 in order to try and see stuff coming back through 0:17:43.280 --> 0:17:50.160 the monitors. Um if because because you're relying on that reflection, 0:17:50.200 --> 0:17:51.679 if it's too far away, you're not gonna be all 0:17:51.720 --> 0:17:55.479 se very well. So obviously a sniper rifle, where at 0:17:55.560 --> 0:17:57.480 least in theory, you want to be able to put 0:17:57.520 --> 0:18:00.400 your snipers at a good distance away from the targets 0:18:00.440 --> 0:18:03.480 to maximize their effectiveness and minimize the chance that they 0:18:03.520 --> 0:18:06.960 will be targeted. Um it doesn't. It's not so effective 0:18:07.000 --> 0:18:11.399 if you know your your distance is cut down that dramatically. Yeah. Plus, 0:18:11.440 --> 0:18:15.960 the first generation wasn't exactly um useful for someone like 0:18:16.000 --> 0:18:19.560 a sniper, considering the batteries were huge and the i 0:18:19.760 --> 0:18:23.760 R emitters had to be carried on flatbed trucks. It's 0:18:23.760 --> 0:18:26.000 hard to put one of those up in a tree. Yeah. Yeah, 0:18:26.040 --> 0:18:29.240 it turns out that also all of these are going 0:18:29.280 --> 0:18:32.320 to involve having a power supply of some sort. But 0:18:33.000 --> 0:18:36.080 for the active infrared it requires either more more energy 0:18:36.119 --> 0:18:38.960 because you're not you're not just for your your actual 0:18:39.119 --> 0:18:41.960 night vision device, whether it's a scope or goggles or whatever, 0:18:42.040 --> 0:18:45.399 but also for the emitter. By the way, that generation 0:18:45.560 --> 0:18:49.639 is normally referred to as generation zero for a night vision. 0:18:50.160 --> 0:18:56.240 Generation one was the first generation using passive infrared system. Now, 0:18:56.280 --> 0:18:59.480 this was the kind of of night vision goggles or 0:18:59.720 --> 0:19:03.240 scope that could just use the ambient light in the area, 0:19:03.280 --> 0:19:06.439 although it needed a good amount of the ambient light. 0:19:06.560 --> 0:19:11.160 So moonlight or starlight. It's funny you should say starlight. Yeah, 0:19:11.200 --> 0:19:12.560 that's what it was called. Yea in the U. S. 0:19:12.680 --> 0:19:17.760 Army they called it starlight. Uh, the without the moon 0:19:17.920 --> 0:19:19.880 or stars, you wouldn't be able to see very much. 0:19:19.880 --> 0:19:23.440 So on an overcast night it would not be terribly useful. Yeah, 0:19:23.480 --> 0:19:25.680 but on a clear day you could see forever. You 0:19:26.080 --> 0:19:29.520 got a clear day, you don't need night vision. Okay, 0:19:29.840 --> 0:19:35.639 starlight first star I see tonight. Um, so yeah, it 0:19:35.720 --> 0:19:39.359 was better than Generation zero. Still still pretty far acry 0:19:39.400 --> 0:19:43.240 from what we have today. Although interestingly, if you were 0:19:43.320 --> 0:19:45.960 to go out and buy a pair of night vision goggles, 0:19:46.000 --> 0:19:51.520 you know, a consumer brand version would probably be Generation one, 0:19:51.760 --> 0:19:54.840 I would guess, you know that's the military tends to 0:19:54.880 --> 0:20:00.399 reserve the more the more advanced forms generations. It's they 0:20:00.400 --> 0:20:03.760 could be generation two as well. Generation two where they 0:20:04.359 --> 0:20:07.800 had better UH image intensive fire tubes, which meant that 0:20:07.840 --> 0:20:11.840 they could use them in extreme low light conditions. So 0:20:12.080 --> 0:20:14.440 on a moonless night, you could use these and it 0:20:14.480 --> 0:20:17.680 would be strong enough to be able to to amplify 0:20:17.720 --> 0:20:20.440 that light. So you can see. Generation three is what 0:20:20.680 --> 0:20:24.120 you can find in the U. S Military now, UM, 0:20:24.160 --> 0:20:27.639 and that is they used a new kind of photo 0:20:27.680 --> 0:20:30.840 cathode called gallium arsenide, so it's even more sensitive than 0:20:30.880 --> 0:20:33.560 the previous ones, which means that you know, it's it's 0:20:33.600 --> 0:20:37.480 not that the UH they've really advanced the technology that much. 0:20:37.520 --> 0:20:41.520 They just found a material that that emits electrons much 0:20:41.520 --> 0:20:44.240 more readily than others. Yeah. As a matter of fact, 0:20:44.280 --> 0:20:46.320 I believe we talked about gallium arsenid when we talked 0:20:46.320 --> 0:20:49.359 about transistors. I believe we did some months back. Yeah, 0:20:49.520 --> 0:20:54.000 and then we have generation four, which is yet more 0:20:54.080 --> 0:20:58.200 improvements UH and it works both in UH in low 0:20:58.280 --> 0:21:02.200 and high level light environments, which that's important too, because 0:21:02.200 --> 0:21:05.040 some sometimes you're in an environment where you're gonna have 0:21:05.119 --> 0:21:09.000 more light than UH than well, let's take two separate 0:21:09.119 --> 0:21:11.160 nights Okay, we have one night where let's say there's 0:21:11.160 --> 0:21:13.880 a lot of moonlight, Uh, there's starlight. There might even 0:21:13.880 --> 0:21:17.200 be some some lights set up in whatever it is 0:21:17.240 --> 0:21:20.000 you're looking at, Like let's say it's an enemy encampment. 0:21:20.040 --> 0:21:23.359 Let's say you're sniper looking at an enemy encampment. Uh. 0:21:23.480 --> 0:21:27.880 If you're using a device that's meant for low light environments, 0:21:28.080 --> 0:21:30.520 you might not be able to see anything anyway, because 0:21:30.560 --> 0:21:33.560 all of that light just overwhelms the device, and so 0:21:33.640 --> 0:21:35.239 you all you see is just a big, you know, 0:21:35.440 --> 0:21:38.840 green screen. Uh. So you need to have one that 0:21:38.880 --> 0:21:42.960 can work in both kinds of situations. Um. So yeah, 0:21:43.000 --> 0:21:49.080 that's your basic that's your basic. Uh. Image enhancement style 0:21:49.320 --> 0:21:52.360 night vision. Chris and I are about to wrap up 0:21:52.400 --> 0:21:54.919 this discussion about night vision, but before we get to that, 0:21:55.000 --> 0:22:05.880 let's take another quick break to thank our sponsor. Now, 0:22:06.160 --> 0:22:11.399 I guess we can move on to the the thermal devices, 0:22:11.440 --> 0:22:15.159 which again can look at you can look at stuff 0:22:15.880 --> 0:22:18.560 and see the energy it's giving off, the light it's 0:22:18.600 --> 0:22:22.000 giving off even though light uh, an outside source of 0:22:22.080 --> 0:22:26.800 light isn't necessarily present. M And this has to this 0:22:26.880 --> 0:22:31.040 involves the whole concept of excitation. Yeah, yeah, Now, you 0:22:31.080 --> 0:22:34.080 have to have a special type of lens to use 0:22:35.200 --> 0:22:39.160 when you're working with thermal imaging basically to identify the 0:22:39.200 --> 0:22:42.520 infrared light. And you've got to what happens is once 0:22:42.560 --> 0:22:45.640 the light is focused through the lens, UM I phased 0:22:45.800 --> 0:22:51.200 array of infrared detector elements scans it UM basically trying 0:22:51.240 --> 0:22:54.719 to create a pattern called a thermogram, which shows you 0:22:54.800 --> 0:22:59.040 the different ranges in temperature UM. And this can be 0:22:59.080 --> 0:23:02.800 done pretty quickly, about one of a second. Yeah, so 0:23:03.600 --> 0:23:07.760 like okay, thirty frames a second essentially, so yeah, and 0:23:07.760 --> 0:23:09.960 considering that film is twenty four frames a second, that 0:23:10.080 --> 0:23:12.440 is that's Yeah, it's fast enough so that you can 0:23:12.480 --> 0:23:15.200 get a good view. So even if something's in motion, 0:23:15.920 --> 0:23:17.720 you should be able to get a pretty good view 0:23:17.760 --> 0:23:20.520 of it. Yeah. And then and then, very much like 0:23:21.000 --> 0:23:25.200 the other style, it creates a thermogram UH and then 0:23:25.240 --> 0:23:30.000 translates it into an electric impulse UM just like that, 0:23:30.080 --> 0:23:33.000 and then it's sent to a signal processing unit which 0:23:33.040 --> 0:23:39.840 is basically UH electronic circuit board UM and UH. Instead 0:23:39.960 --> 0:23:45.760 of converting electrons to photons, it actually creates a display 0:23:45.920 --> 0:23:50.160 of information UM. So it's more like a computer than 0:23:50.200 --> 0:23:53.120 it is an ocular system with the other one. Yeah, 0:23:53.080 --> 0:23:54.760 you wouldn't have a lens. You would have a monitor 0:23:54.800 --> 0:23:57.920 of some site, some type. Now that motor might be small, Yeah, 0:23:58.160 --> 0:24:00.760 so it could be a motor they then probably Yeah, 0:24:00.760 --> 0:24:05.160 it could even fit into a headset or or binoculars 0:24:05.240 --> 0:24:08.000 or whatever. Um. Yeah, this is the what I was 0:24:08.040 --> 0:24:10.800 talking about with the the documentary Predator, where you've got 0:24:10.880 --> 0:24:15.360 the different colors representing different temperatures. So if you've ever 0:24:15.359 --> 0:24:21.359 watched any ghost hunting shows where they use thermal detectors 0:24:21.400 --> 0:24:24.720 to try and see if there are cold or warm spots, 0:24:25.200 --> 0:24:28.080 that's what they're using. By the way, just so just 0:24:28.359 --> 0:24:32.359 side note, the air can actually retain heat for a 0:24:32.359 --> 0:24:34.800