Night Vision / ThermalCapability Comparison
The term "night vision” actually covers two technologies:Image Intensification and Thermal.  Thesetwo technologies have undergone significant development over the past 25 yearsand made tremendous leaps in the past 15 throughout the Global War on Terror.  They have provided unprecedented advantagesto the warfighter on the battlefield and law enforcement professionals in theirnever ending struggles to keep this country safe.  And like most technologies born on thebattlefield, tactical eventually becomes practical.  With the rising popularity of nighttime hogand predator hunting in the United States, more and more hunters are findingthemselves shopping for night vision gear. Night Vision Hunting has become the fastest growing segment of thehunting market and many hunters are asking: "what type of device is best forme?”  The law enforcement community isasking itself these same questions as many agencies are finding a need tobetter equip themselves at night in order to keep the streets safe.
With the sudden surge in night vision popularity amongprofessional end users and sportsmen, it is important to understand thedifferences in the technologies offered on the market.  Often times, the capability requirements ofboth end user groups overlap.  To thisend, we wanted to put forth an education primer on the general performancecapabilities of image intensifiers and thermal devices.  Please note that there are many differentbrands, makes, models, etc. available. We are well aware (and you should be too) that the performance range canvary greatly depending on the device. This article is not going to get into a brand vs. brand or model vs.model battle.  The intent is to providegeneral information that can be extrapolated over most night vision devices onthe capabilities of the various technologies. This discussion is aimed at providing end users with an idea of whichtype of device will be most beneficial for their mission.
Let’s begin by discussing the differences between the twotypes of night vision.
Image Intensifiers are more commonly referred to simply as"night vision.”  For the remainder of thearticle, I will refer to image intensifiers as "night vision.”  Night Vision uses a powered image intensifiertube to produce a light-amplified image to the user.  The tube literally amplifies existing ambientlight to produce a bright, detail-rich image. Traditional night vision produces a green image to the viewer.  Green is the most visible color to the humaneye.  We can see more shades of greenthan any other color in the visible light spectrum.  As such, the green phosphor screen in theimage tube presents the most hues and shades to the user, allowing him/her tobest resolve the image in detail and depth. This is an important positive capability in that night vision users cansee into the dark and gain positive identification of their surroundings andtargets.  Since night vision is simplyallowing you to see in the dark, it is completely possible to achieve positiveidentification of faces, clothing, animals, etc.  This is perhaps the most important aspect ofnight vision.  Since night vision devicesare mostly used in conjunction with a firearm, the ability to achieve 100%Positive Identification (PID) is critical before taking a shot.  Night vision will allow the user to readsigns as well.  Another important aspectof night vision is that it allows for easier depth perception while moving.  Because the tube is amplifying existingambient light, shadows and terrain undulation can be more easilyidentified.  This helps night visionusers to gauge distance using terrestrial association.  The key benefit to night vision is itsidentification capability.
However, despite the benefits of night vision, it is not aperfect tool.  Like our eyes, we aresusceptible to being fooled by camouflage. Nature has the ability to camouflage people, animals, and objects simplyby placing foliage in front of them. Sometimes, possible targets will go out of their way to camouflagethemselves in the terrain.  Bad guys canwear camouflage clothing and attach foliage to their person.  Animals often have natural camouflage intheir coats.  The same camouflage thatworks for a person or animal during the day will work just as well, if notbetter, through night vision (after all, the image is the same as normal, butnow being presented in a single color palette). Night vision may also be slightly harder to use during inclement weatherconditions such as rain, snow, fog, and smoke. Another, more obvious, deficiency in night vision is that it only worksat night.  However, we have to rememberthat night vision requires some amount of ambient light to function.  Today’s Gen3 tubes can do much more with muchless light, we still need to have some illumination to gather.  If you take a brand new Gen3 device into anabsolute pitch black environment, you will not have any image.  At that point, an external infraredilluminator is required.
Thermal imagers work differently than night vision.  Rather than amplifying the existing light inan image, thermal uses a special detector that senses infrared energy.  Infrared energy is produced by everything inthe world, whether natural or man-made, and increases as its heat rises or it producesfriction.  So essentially, thermalimagers detect heat, providing a starkly contrasted image where heat-producingtargets and objects will light up against their cooler surroundings.  This trait makes thermal imagers ideal fordetecting targets in the user’s environment. The most obvious use for thermal devices is easy detection of targets inthe field.  The warmer an object is, thebrighter it will appear in the thermal device. An animal or person that is hiding among foliage will more easily bespotted against the landscape since the user is not depending on the shadingand tones of the target for detection. Detection is the most important aspect of thermal imagers.  These devices will allow users to quicklydetect the presence of a possible target against a wide range oflandscapes.  Thermal imagers can also beuseful in tracking blood trails and, depending on the time lapse; foot prints.  This can be useful in finding suspects oranimals.  Thermal is also capable ofseeing through light rain, snow, fog, and smoke.  Another positive trait for thermal devices isthat they can be used during the day. Night vision will eventually become damaged when exposed to too muchlight for extended periods of time. Thermal devices can operate regardless of the ambient light present.  This includes high noon or absolute pitchblack.  Though, thermal devices do tendto work better at night because the ambient environment will have cooled down,increasing target contrast.
While thermal devices excel at detection, they are not asuseful for identification.  It ispossible to get a decent level of identification capability out of a thermal ifit is a high resolution system (such as 640x480).  However, facial recognition and PID is notgenerally possible.  Thermal is alsoincapable of reading text printed on a flat surface.  This is most easily demonstrated by lookingat a sign or a garment.  If the lettersare raised or have a different finish than the rest of the surface, it may bepossible to make out the graphic, but you will not get nearly the legibility ofnight vision.  Positive Identification isperhaps the biggest drawback to using thermal. Obviously, the higher resolution systems will be able to resolve moredetail in an image.  However even theyare going to be lacking in the ability to clearly identify someone’s face orone type of animal from the next.  From aprofessional standpoint, this means that identifying an armed suspect from anarmed officer is going to be more difficult. For hunters, it can make it more difficult to tell the differencebetween a coyote and dog.  Though, we cansurmise differences in our thermal targets by observing their movement andbehavior, it is important to remember that we are most often dealing withfirearms in conjunction with these devices. Once the trigger is squeezed, the possible outcome is the loss of alife.  The consequences of mistaking acalf for a hog can be a $13,000 bill from the ranch owner.  The consequences of mistaking a good guy fora bad guy can mean life in prison.  Andthe consequences of mistaking someone’s dog for a coyote can mean the dog’sowner hunting you down.  The issue isexacerbated at distance since electronic zoom cuts the image resolution everytime.  Thermal imagers are also incapableof seeing through glass.  Because ofthis, their lenses are made from an expensive material called germanium.  But this limitation can be detrimental tosurveillance operations, or if a hunter wants to observe the field from his/hervehicle cab.  One last thing to considerwith thermal imagers is the video frame rate. Thermal imagers are active systems that provide the user a video on anOLED screen to view through the eyepiece. So unlike night vision, a user does not look "through” thermal and seethe world.  Real time video runs at 60 Hzand some thermal devices display at this frame rate.  But, most thermal units run at 30 Hz.  This means that the video image you observecan experience some slight clipping during fast movements.
Again, the above information is a simplistic overview orthe characteristics and pros/cons of night vision and thermal imagers.  Depending on the device you possess, some ofthe characteristics can vary.  Now thatwe have established a baseline idea of the capabilities present in thesedevices, let’s take a look at how they are applied to some practical scenarios.
**DISCLAIMER**
We chose to bias these videos towards the first-respondermarket.  We felt they would best displaythe capabilities of the various night vision devices in different environments andcould be easily juxtaposed across the hunting and military markets aswell.  No live firearms were used in theproduction of these videos.  Also pleasenote that filming through night vision devices is incredibly hard to do becausethe focus of the night vision device and the camera are not always in perfectsync.  We did our best to provide asaccurate a representation as possible.

SCENARIO 1






This video is shot through a law enforcement officer’spoint of view.  It represents theaftermath of a foot chase where the fleeing suspect would have thrown awayevidence in hopes of not being caught with it on his person.  The suspect is in custody and we must nowsearch the area where the object was tossed in an effort to recover it forevidence.
In the first part of the video, we show the officer using atime-honored tool found on every peace officer’s duty belt: theflashlight.  Most of the time, individualpatrol officers are not going to have access to night vision equipment, so theyhave to make do.  During the flashlightsweep, we can see a ton of detail.  Asthe officer walks along the brush line, he sweeps the light over the foliage.  But at this distance, the light splash isalmost too bright against the leaves, causing a whiteout.  This hinders the officer’s ability to seedetail and the outer spill of the light beam must be used.  In fact, the light almost shows too muchdetail, effectively camouflaging the object in question.   If wewere to extrapolate this scenario into a full-on search, it could easily besurmised that the officer(s) would be out there all night, searching a longstretch of brush to find whatever was discarded by the suspect.
The next part of the video shows the same scenario through anight vision monocular.  In this case,the night vision helps the officer see a larger area lit up.  But, the dense foliage still provides achallenge to the officer trying to find the discarded evidence.  As mentioned earlier, the same camouflagethat works during the day is going to be just as effective at night.  Another issue we see is the focallength.  Night vision devices focus on afixed focal plane and must be manually adjusted to refocus up close.  Users want to generally achieve a baselinefocus where objects will be nice and crisp from about 10 yards out toinfinity.  But, night vision will notautomatically refocus when trying to observe things up close and must be donemanually.  This can be challenging duringa search like this where the focal plane constantly changes.  A long sweep of the area yields little resultand can be especially difficult it the officer is unsure of exactly what he islooking for.
The final section of the video shows the search while usinga thermal device.  The first thing youwill notice is that the detail seems to be way less than the night vision andflashlight segments.  This is becausethermal will generally have a harder time differentiating between cooler objects.  You can also see that the undulation interrain as the officer walks up to the brush line, is more difficult toascertain and can make land navigation more difficult when using a thermaldevice.  But in terms of accomplishingthe mission (finding the discarded evidence), the thermal device seems to winthe night.  As the officer walks up tothe brush line, the heat signature of the discarded item is almost immediatelyvisible through the dense foliage.  Theheat from the suspect’s body was transferred to the object and it is still warmenough to be visible to the thermal device after 15 minutes.  The discarded evidence turns out to be apistol.  On a side note: thermal, likenight vision, must be manually focused for up close detail duringobservation.  While the point of thisparticular exercise was to find the evidence, you will notice that there is adistinct lack of detail up close when the gun was recovered because the thermaldevice was not refocused during the pick-up.
In the first scenario, thermal is the clear choice due toits awesome detection capability when compared to the other viewing methods.

SCENARIO 2






This video shows the point of view of a SWAT marksmanresponding to a hostage situation at a local business park.  The armed suspect is using a hostage as ahuman shield in the front atrium as he communicates with the on-scene hostagenegotiator.  The officer is given ordersto hold on the target, but must be ready to take a crisis shot on the suspectif negotiations break down and the hostage is thought to be in immanent danger.
We first see the officer’s view through a standard dayscope.  As we can see, the darkenedatrium presents an almost impossible view. Movement can be seen through the building’s glass door, but withoutlighting, it is impossible to decipher what we are looking at.  The officer cannot determine who the hostageis from the suspect.  Everything is incomplete shadow making a crisis shot impossible and putting the hostage indanger.  It’s not until the suspect makesthe hostage open the door that the outside lights provide enough illuminationto take a clear shot.  However, if thesuspect closes the door again, the officer will be back in the proverbialdark.  Clearly, the use of a standardrifle scope in this situation would not only put the hostage’s life in jeopardy,but it perfectly illustrates the handicap created when a responding lawenforcement agency lacks night vision capability.
In the second part of the video, we see the same situationplayed out through a dedicated 4X night vision weapon scope.  Here, we can easily see into the darkenedbuilding and make out both the suspect and his hostage.  We can see that the suspect has asemi-automatic pistol held to the hostage’s head and is standing behind him.  In fact, the night vision image allows forclear identification of the suspect and his hostage.  The officer not only knows where to shoot, ifrequired, but he knows who the suspect is. We can easily determine that the suspect is an adult male with shorthair and a larger build.  We can see thatthe hostage is also an adult male with short hair, a beard, and an athleticbuild.  We can even see when the suspectand hostage are speaking (or in the case of this role-play, we can see whenthey are laughing because the "suspect” is yelling out crazy stuff).  When the door is opened, the outside lightscreate a slight bloom on the two individuals, but the level of detail and identificationcapability does not change.  In asituation like this, night vision is giving the officer a commanding edge.
In the final segment of this video, we observe the samesituation through a thermal weapon scope. While the building is clearly seen to include the columns, lights, painton the parking lot, we are faced with a show-stopping problem: thermal does notsee through glass.  While the hostagenegotiator is talking with the suspect, the marksman has absolutely no way ofobserving the situation, rendering him unable to take a critical shot shouldthe need arise.  It is not until the suspectforces the hostage to open the glass door that we can even see that anyone isthere.  When the pair are finallyexposed, the officer is given enough data to see who is who and that there is apistol to the hostage’s head.  But, thethermal unit does not provide any facial detail.  In this circumstance, the thermal scope isset to no magnification in an effort to retain as much resolution aspossible.  Resolution is critical in thissituation because the officer may have to take a shot within a fraction of aninch.  If he were to use the electroniczoom, he would lose resolution and hinder his ability to identify the criticalshot.  
The night vision weapon scope is the clear winner in thisscenario.  The standard day scope rendersthe marksman impotent to affect any type of resolution to the situation and thethermal scope was arguably a liability. Yes, the suspect and hostage became more clearly visible when the doorwas opened.  But, without a green lightto take the shot, the pair could just as easily go back inside the atrium,placing the officer in the same situation again.

SCENARIO 3






The third scenario simulates recorded surveillance video ofa known drug deal/bad-guy meet location behind a local strip mall.  The officers have set up in a concealedlocation to film this corner where criminal activity is often committed by gangmembers according local residents.  Thehope is that the police department can identify the drug dealers/trouble-makersand start building cases against them. However, PID must be achieved in order for evidence to be admissible incourt.
The video starts out through a thermal imager.  We can clearly see four subjects gathered inconversation at the back corner of this L-shaped strip mall.  The overall height and build of the subjectscan be identified as well as their clothing type.  It can be confirmed that we are observingfour grown males.  All are wearing shortsleeve shirts while two are in shorts and flip-flops and two are in pants andshoes.  Ball caps can be seen on all ofthem.  We can clearly see the subjectsloitering about, talking and interacting with small electronic devices.  The detail level is quite good overall.  We can see that the shortest subject has abeard that gets longer at the chin and the suspect facing the camera also hasfacial hair.  However, it is impossibleto identify the faces of the subjects or their ethnicity.  We can certainly see other details such asthe fact that the subject facing the camera is wearing cargo pants and seems tobe chewing gum.  When one of the subjectsmotions to something in the distance, causing the closest subject to turnaround, we can clearly see that he is wearing glasses and has a beard.
The second half of the video shows the same group ofsubjects through night vision.  Again, wecan immediately recognize four grown males as well as their height andbuild.  We can see that they are alllight-skinned; possibly White or Hispanic. While the ethnicity cannot be clearly ascertained, it is possible torule out that we are observing Black males or darker-skinned individuals.  Clothing can be identified as two subjectswearing pants, two wearing shorts, and all wearing ball caps.  Printed shirt graphics can also be seen aswell as the overall brightness/tones of the shirts.  This information could be useful if a crimeis committed during the surveillance and the observing officers need to providean immediate description of the suspects to other officers.  One of the main things to note is that facialfeatures can be recognized enough to identify individuals.  
Both thermal and night vision provided a good nighttimesurveillance tool.  The location wasquite dark with any surrounding light sources facing away from the scene.  Regular video surveillance would have beenimpossible. Depending on the mission, thermal or night vision could make aneffective tool for monitoring individuals or areas.  For a business or personal security system,thermal will definitely provide good data and allow users to recognizeprominent features on individuals.  Nightvision provided this same data, but allowed the individuals to be identified.  For professional use, this is an importantpoint.  Law enforcement officers need tomake a case and be able to prove everything in court beyond a reasonabledoubt.  Warfighters need to identifysubjects while working up target packages. But, civilian property owners may just need to see that there are peoplewho shouldn’t be there, doing things they shouldn’t be doing.  In that case, either technology will sufficein the dark.  This particular scenarioshowed a video from a good vantage point where the four subjects could beclearly seen.  Obviously, this is notalways going to be the case during a surveillance operation.  The thermal device being used was a 19mm640x480 1X monocular.  The night visiondevice was a Gen3 monocular.

SCENARIO 4






In this scenario, we are put into the shoes of a lawenforcement officer providing perimeter security at the back of a commercialbusiness that is a front for selling drugs, during a raid.  An undercover officer is inside.  As the assault element makes entry at thefront of the building, we see two individuals go running out the back.  The inner perimeter officer has a few secondsto determine what to do.  Are they bothsuspects?  Is one a suspect and the othera cop?  As the two subjects run, we jumpto the point of view of one of the outer perimeter officers who witnesses thesame two subjects run through a gate into a residential yard.  These situations can develop rapidly andradio communications can sometimes become garbled or confused.  Usually, officers have very little time toprocess the situation and make a decision when use of force is called for.
At the start of the video, we are looking through a thermalimager and we see the first subject burst through the door, turn, and run awayfrom the camera.  We can ascertain adecent amount of information.  We can seethat he is male, athletic build, wearing shorts, T-shirt, and flip-flops.  He appears to have some facial hair and isarmed with a pistol.  The subject appearsto be trying to get away without regard to who or what may be in his immediateenvironment.  The second subject followsclose behind the first.  We can see thathe is male, larger build, does not have facial hair, and is wearing a shortsleeve shirt and pants.  This subject isalso armed with a pistol.  We can alsosee that his behavior is different than the first subject.  While the first guy immediately came runningout the door and took off away from the camera, the second guy has his gun at alow ready and takes a quick glance forward before running in the same directionas the first.  What does this tellus?  The inner perimeter officer has acouple seconds to decide whether or not to engage the first, second, or bothsubjects.  Neither subject’s face can beclearly identified through thermal, nor can their clothing.  The first subject is probably a fleeingsuspect based on his behavior.  But, isthe second guy a fleeing suspect or a fellow officer giving chase?  After all, the raid is being carried out byofficers not in traditional uniform… The second guy seems to exhibit some moreprofessional gun handling behavior.  Butat the same time, there are many bad guys out there with firearms and tacticaltraining today.  Either way, the innerperimeter officer does not have enough data to engage these subjects withforce.
From here, we switch to the view of one of the outerperimeter officers.  The two subjects randown the alley, away from the first officer’s position, went through a gate,and entered a residential yard.  Theouter perimeter officer and his K9 observe the first subject running throughthe gate with the second right behind him. The first guy turns and both subjects draw down on each other.  What do we do?  At this point, it can be safely assumed thatone of the subjects is a cop and the other is a bad guy.  But the situation is more complex than we seeon the surface.  At first, we would thinkthat the guy being chased is the bad guy. But, as an outer perimeter officer, we know that there was an undercoverofficer inside the building.  At theonset of the raid, he was going to run so as to not blow his cover.  But, was his cover compromised anyway and heis being chased by one of the suspects who knows he is going to get caught, butis intent on killing this "traitor” before he goes down?  Everything is happening in a split second andthe outer perimeter officer is about to watch two individuals, one of them cop,engage each other at close range.  Hisheart is beating through his chest and the blood is rushing in his ears.  The damn frogs in the pond behind him won’tshut up either.  With the stress levelthrough the roof, he doesn’t have 100% PID on either subject to make a shot.
In the second half of the video, we see the same scenarioplay out through night vision.  The innerperimeter officer can immediately see the same details visible in the thermalvideo: grown male subject with facial hair in T-shirt, shorts, flip-flops, andarmed with a pistol comes bursting out the back and takes off down the alley.  The second subject is following close on hisheels.  He wears a short sleeve shirt,pants, has no facial hair, and is also armed with a pistol.  The differences start when we see that bothsubject’s facial details are visible and identifiable.  The inner perimeter officer can get a quickglimpse of the faces and get an idea of who is who.  But, as the second subject rounds the cornerafter the first, "POLICE” is clearly printed on the back of his shirt.
As the chase continues into the residential yard, the outerperimeter officer can clearly the see the same details as the two subjects drawdown on each other.  Now, this splitsecond decision is able to be made because it is clear who the suspect is.  The outer perimeter officer can engage thesuspect and help to save his buddy’s life.
While it is pretty obvious that officers equipped withnight vision devices would be better off in this scenario, there are otherfactors we should acknowledge.  Thesevideos show great clarity and contrast of thermal devices.  The subjects seem to literally pop out oftheir environments.  It is incrediblyeasy for someone equipped with thermal to follow these subjects.  The night vision devices allowed the officerto identify the subjects, but the detection limitations start to show.  Notice how the first subject started to blendinto the tree line as he ran away from the inner perimeter officer.  While night vision provided more depth to theimage, the light sources behind the tree line started to make it more difficultto follow the subjects.  This can againbe seen in the residential yard.  Whenthe first subject spins to engage the second, he is standing with a house andfoliage behind him.  This helps toconceal him slightly.  While he can beseen, he is not popping out of the camera as he does when viewed through thethermal imager.  This is a complexscenario that shows benefits and deficiencies of both technologies.  Night vision edges out thermal in this case,due to its identification capability, but it is not without its shortcomings.

SCENARIO 5






Here, we see another surveillance video that simulates adrug/contraband buy.  We show twodifferent takes on this scene.  The firstone has the suspect enter the truck on the driver’s side.  Another subject approaches the driver’s sideshortly after and some sort of transaction appears to take place.  The second take on this scene shows a subjectentering the truck on the passenger side. A transaction appears to take place, the subject exits the vehicle, andleaves.
As we saw earlier, thermal imagers do not see throughglass.  So, vehicle surveillance becomesalmost impossible to conduct.  The videostarts out with the suspected dealer entering the truck.  It is impossible to determine if he is alonein the vehicle.  Once he enters the cab,he is completely obscured from view.  Wewatch as the second subject approaches the vehicle.  We can see that he is wearing a T-shirt,shorts, flip-flops and hat.  His beardcan be identified as well.  Beyond that,there is no other facial recognition.  Atransaction of some sort appears to take place where the outside subject handssomething to the guy inside the truck and takes something in return beforeleaving.  As observers, we are completelyblind as to what is happening inside the truck through the thermal device.  In fact, we cannot even be sure that thefirst subject who initially entered the truck is the same one interacting withthe second suspect who later approaches because we do not know if anyone elseis in the vehicle.
Next, we see the same scene play out through nightvision.  As the suspected dealerapproaches the truck, we are able to get clear facial recognition.  However, one of the deficiencies in nightvision becomes immediately apparent when he unlocks the truck and enters: halobloom.  The headlights and mirror lightsare activated when the truck is unlocked and the scene is almost completelybloomed out for a few seconds.  A lot ofthe bloom is actually exacerbated by the camera that is recording through thenight vision goggle.  If we were to be lookingthrough the night vision device with a naked eye, we would still see somebloom, but not as bad as what a camera adds. Nonetheless, this issue with night vision must be taken intoconsideration when filming through night vision for evidence.  Once the suspect is in the truck, the lightsare turned off and we can clearly see into the cab.  We know that he is alone in the vehicle andwe can still clearly identify him.  Wewatch as he talks on his cell phone.  Later,we see the other subject approach the truck. His face is also identifiable, though there is some extra light from offcamera, which is somewhat washing out his face. We are able to see the transaction take place as the driver reaches forsomething under the dash or in the center console.  The object is handed to the outside subjectand the exchange is complete.  At thispoint, we have evidence that the original subject that entered the vehicle wasthe only one in the truck and carried out the exchange with the suspectedbuyer.
In the next take, we watch a subject approach the truckfrom the passenger side, through a thermal device.  Again, we can make out his clothing andbuild, but we cannot get detail from his face. He enters the passenger side of the cab and completely disappears fromview.  The subject stays in the truck fora little while and then exits and walks away. He is not visible again until he is out of the truck.  At this point, we have no idea whattranspired in the truck, let alone have anything we can build a case on.
Next, we see the same scene play out through night vision.  We watch the subject approach the truck whichalready is being occupied by a male driver, clearly seen through thewindshield.  As the subject enters thepassenger side of the truck, we are again blinded in the video by the excesscamera bloom created by white light sources. Again, this is not typical when viewing auto-gated Gen3 tubes with thenaked eye, but is a factor you must contend with when filming.  In the vehicle, we can clearly seeinteraction between the two subjects.  Anexchange appears to have been made and the first subject exits the vehicle withsomething in his hand and walks away.
This set of videos makes it quite apparent that thermalimagers are not ideal for vehicle surveillance. While filming through night vision has its drawbacks in bloom created bythe camera from light sources, it is still the clear choice when one needs tosee through glass.  

Night vision and thermal imagers are incredible tools thatoffer undeniable advantages to professionals and amateurs alike when operatingin the darkness.  However, there is nomagic device that will offer a perfect solution for every situation.  Like everything else, you must choose theright tool for the right job.  Thescenarios above were designed to provide overall examples of situations thattoday’s professional could find himself in. The scenarios were meant to illustrate the capabilities and deficienciesfound in these technologies to aid you determining which one is best for yourmission.  While these videos focused moreon the professional end-user, it is easy to look at the data and juxtapose itover the civilian’s mission as well.
This is the first in a series of comparison videos betweennight vision and thermal that we will produce at TNVC.  The next series will focus more on ruralapplications.  We hope you found thisdata educational, relevant, and enjoyable.  Stay tuned over the next few months for more.
**UPDATE** 06/07/2016
SCENARIO 6
















SCENARIO 7




























































 

Good article.  Thanks for posting.  Think I discovered an error though.  Not an expert, but have over 500 pilot hours on aviation night vision systems from Gen 2 through ANPVS 9s.  The following was not true when the technology was taught to me:


" So unlike night vision, a user does not look "through” thermal and see the world. Real time video runs at 60 Hz and some thermal devices display at this frame rate. But, most thermal units run at 30 Hz. This means that the video image you observe can experience some slight clipping during fast movements."

I believe that in an image intensifier you don't look "through" anything either.   Images hitting the photocathode are accelerated to the micro-channel plate.  This releases electrons that then hit the phosphor screen that produces an image through the eyepiece lens.  We used to say that you're watching TV.  So in neither technology are you looking through the device.

Forgive me if there has been some recent change in the technology.

Nice write up!

thanks for all the hard work

Hi Bighat,



Actually, in context, the article is correct - people do look through night vision, while they do not look through thermal, but at a recreated image that does not exist in reality, or even within the thermal monocular itself.



Without going into the semantics, image tubes are known as "image converters" so although you're not seeing the original photons, you are seeing their impression in real time, amplified many thousands of times ( typically around 7000 times for a PVS-14 ) and delays in the image are, for all intents and purposes, non-existent. Also, each photon creates an image in real time, and single photons can be made visible - in this respect, it's a completely real-time system - it's just being amplified. Sure, what we're looking at is a map of the photon strikes on an image plane, but we're seeing them, so the system functions as though we're looking "through" it. What you're seeing is a representation of what the eye would see if it was sensitive enough and could view the spectrum that the image is presented in, and any slowness in the system is attributed to the eye.



In the case of thermal, this is completely different, and the mechanics of the difference must be fully understood to realize the issues it causes in real-time applications, such as flying an aircraft or aiming a weapon.



Firstly, it's not image conversion - The image is detected by a focal plane array, which while it converts thermal data to electrons, doesn't work anything like an image converter. Attempting to amplify this electron data would result in no image at all - just noise. The image must be processed by a computer which determines what the pixel on the array is actually seeing - and it then generates a false image based on this information, which is displayed. It would be easy enough if this was the only difference, but there's more to understand.



The raster ( the image plane that's created ) is serial, not parallel, so you're updating it one pixel at a time - Even if everything else was equal, this makes it up to a million times slower than an image converter... and the key word here is "up to" because for any section of the image, it might be real-time or it might be from 40 milliseconds ago @ 25 hz. That might not seem like much, but if you're aiming real-time at something that's moving, say at 10m/s, that's more than a foot of random variation between where you think it is and where it really is.



Finally, there's the frame buffer time, which is undetermined, so add on up to an additional frame or three depending on how good the image processing is, and now high-speed objects will be up to a yard away from where you think they are. And when I say "high speed" I mean high as in people running, or animals, etc, not even vehicles, or
relative motion caused by moving your head around and panning, which is
orders of magnitude faster.



So as a result, you're looking at an image that is recreated, with random errors in position based on speed of motion, that occured several fractions of a second ago - not right now.



This is the difference between "looking through" and "looking at a near-time image" of an object -



Hope this helps -



Regards

David



p.s. Excellent article Chip - one of the best I've read in a long time - Very pertinent and very insightful - thanks for the good read - :)



 

Bighat, I completely see where you are coming in front that, technically, we do not look through an image tube since it has to be powered in order to start working.  Looking through an image tube without power will yield no image.  But, as CJ pointed out, the intent of the words was more to describe how looking through an image tube shows people the real world as it is happening without recreating the image as video.  Since thermals produce a video, the viewer sees it at whatever frame rate the device is capable of.  While real time video is 60 Hz, most thermals on the market will produce 30 Hz or less.  While you see the world unfold in real time in this sense, the video isn't always as fast and can create clipping/stuttering.

Thanks BigRedDog, glad you enjoyed the article.  The staff put in an enormous amount of work to accomplish this.  We also have more to come in the next few segments.  Thanks again.

Vic

If you guys do another video. You should do a suspect search in a wooded area and an urban area.

IE suspect bails from car/ runs from officers into an area.  

This is why im trying to get both for my agency as its a big force multiplier and really increases safety.

Should sell you some thermals and I2's as this would make it easy to show a chief or other purchasing power why you want something.

I would also show "naked" eye as well on all the videos as that helps sell the units benefits to those that have the power to purchase them.

That is exactly what we will be doing



 

And soon I might add!

Finishing up the 2nd part of this series.  Thanks for the patience as a lot of work has been on-going with this.  

Vic

Updated above. Hope you all enjoy it.

Bump by request.

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