Gun detection in low-light conditions

One of the biggest concerns of police officers is to know whether the suspect they are dealing with is armed or unarmed. Even during the day it can be hard to detect a gun. And in low-light conditions it can become practically impossible. Knowing whether the suspect is armed or not helps officers to make the right decision and take appropriate actions towards him.

How do night vision devices of different generations help in this situation? We at N-Vision Optics have taken several pictures in different light conditions with 1st, 2nd and 3rd generation devices. 

It should be noted, that real life images provided by night vision devices look better than in the pictures, because the camera reduces the quality of the image.

Picture 1 was taken in regular daylight conditions. We used a Bluegun®  for this picture as well as all other pictures below. You can see, that when there is no contrast between weapon and clothes (like in this example – black shirt and blue gun), even in daylight it can be hard to get a sight of a gun. With a real gun the results are a little bit different, but similar. The reflecting capacity of the gun depends on its finish. Some guns have more reflective finish than others and those would reflect light better than rubber handle of our Bluegun®. Other guns, that have matted finish, would be harder to see (i.e. the barrel of our gun is really impossible to notice in the pictures below). So the results that you could see on our pictures are somewhat average.

Varying light conditions. All night vision devices used without aid of IR illuminators.

Pictures 2 through 6 were taken in conditions close to half-moon, overcast.

Picture 2 was made with N-Vision Generation 1 monocular Aurora 23 (NVA23). As a result, only the person’s silhouette can be recognized. Generation 1 night vision is now mostly used for night-time wildlife observations, and it is not recommended to rely on them in life-threatening conditions.

Picture 3 was taken through N-Vision Generation 2+ monocular Professional 29 (NVP29SG), and picture 4 is a close-up made with the same device. This image is notably better than the one made with Gen 1 device, but you still can’t see the gun. 

Pictures 5 and 6 were taken through the N-Vision GT-14 monocular, with Photonis-DEP MilSpec SuperGen (a.k.a. SHD-3) image intensifier tube (Picture 5) and with high quality Generation 3 tube (Picture 6). You can see that the face can be seen better on the last picture, but when it comes to detecting a gun, there is almost no difference between Generations 2+ (Picture 3) and SuperGen (Picture 5). There is also only a small difference in images provided by SuperGen (Picture 5) and Generation 3 (Picture 6) tubes. The contrast is better captured by the Generation 3 tube. The belt is noticeable, and if you look more closely, you can even see the silhouette of a gun attached to the belt.

Picture1. Daylight shot.	Picture 2. N-Vision Aurora 23 Generation 1 monocular. Half-moon, overcast. Infrared illuminator off.	Picture 3. N-Vision Professional 29 Generation 2+ monocular. Half-moon, overcast. IR off.
Picture 4. N-Vision Professional 29 Generation 2+ monocular. Half-moon, overcast. IR off. Closeup.	Picture 5. N-Vision GT-14 monocular with Photonis-DEP MilSpec SuperGen (SHD3) image intensifier tube. Half-moon, overcast. IR off.	Picture 6. N-Vision GT-14 monocular with Generation 3 Pinnacle tube. Half-moon, overcast. IR off.

Pictures 7 through 10 were made in light conditions close to ¼ moon or less, overcast.

The image taken with Generation 1 unit (Picture 7) is close to nothing. Generation 2+ unit (Picture 8) makes it possible to see the silhouette of a person. SuperGen and Generation 3-provided images (Picture 9 –  SuperGen tube, Picture 10 – Generation 3 Pinnacle tube) are more clear, but still not even sign of a gun is present.

Picture 7. N-Vision Aurora 23 Generation 1 monocular. ¼ moon, overcast. IR off. (Compare to Picture 13 – same light conditions, IR on).	Picture 8. N-Vision Professional 29 Generation 2+ monocular. ¼ moon, overcast. IR off. (Compare to Picture 14 – same light conditions, IR on).
Picture 9. N-Vision GT-14 monocular with MilSpec Photonis-DEP SuperGen (SHD3) image intensifier tube. ¼ moon, overcast. IR off.	Picture 10. N-Vision GT-14 monocular with Generation 3 Pinnacle tube. ¼ moon, overcast. IR off.

Pictures 11 and 12 were made in a very dark room with conditions roughly equivalent to the darkest no moon overcast night.

Based on previous results, we concluded that there is no reason to experiment with Generation 1 and 2+ devices, since we didn’t see the gun without the IR illuminator even in conditions when there was more light. In such conditions Generation 3 Pinnacle tube provides us with a clearer silhouette (Picture 12) than SHD3 tube (Picture 11).

Picture 11. N-Vision GT-14 monocular with Photonis-DEP MilSpec SuperGen (SHD3) tube. No moon, overcast. IR off. (Compare to Picture 15 – same light conditions, IR on).	Picture 12. N-Vision GT-14 monocular with Generation 3 Pinnacle tube. ¼ moon, overcast. IR off. (Compare to Picture 16 – same light conditions, IR on).

Varying light conditions. All night vision devices used with assistance of external IR illuminator.

After studying images taken with night vision devices without the infrared illuminator, we are going to do experiments with the use of the IR.

 

Note 1: We have used the same external IR illuminator to assist all night vision devices. This was done in order to avoid inaccuracy, due to the various capabilities of each unit's IR illuminator.

 

Note 2: All the pictures below were taken with the use of IR.

 

Pictures 13 and 14 were taken in light conditions close to ¼ moon, overcast.

On picture 13 you can see an image provided by a Generation 1 device. And picture 14 shows an image of Generation 2+ unit. On both images we can clearly see, that there is a gun on a mans belt contrasting to a mans shirt, which now seems to be white.

 

This happened because of the type of material, which the shirt was made of. Some synthetic fabrics, i.e. polyester, nylon, satin, chiffon and others reflect light better, and because of high quantity of reflected IR illuminator light this shirt looks white. It’s very hard to predict how diferrent kinds of materials (i.e. clothes, or metal that gun is made of) would be seen through a night vision device with an aid of an IR illuminator.

 

In these light conditions we didn’t’ take a picture using a Generation 3 unit with IR on, because as the gun is clearly detected with Generation 2+, it’s obvious, that the image with Generation 3 unit will also show it.

Picture 13. N-Vision Aurora 23 Generation 1 monocular. ¼ moon, overcast. IR on. (Compare to Picture 7 – same light conditions, IR off).	Picture 14. N-Vision Professional 29 Generation 2+ monocular. ¼ moon, overcast. IR on. (Compare to Picture 8 – same light conditions, IR off).

In light conditions that are close to no moon, overcast, it’s really hard to see the difference between Photonis-DEP SuperGen (SHD3) tube (Picture 15) and Generation 3 Pinnacle tube (Picture 16) when the IR is on.

 

Picture 15. N-Vision GT-14 monocular with Photonis-DEP MilSpec SuperGen (SHD3) tube. No moon, overcast. IR on. (Compare to Picture 11 – same light conditions, IR off).	Picture 16. N-Vision GT-14 monocular with Generation 3 Pinnacle tube. ¼ moon, overcast. IR on. (Compare to Picture 12 – same light conditions, IR off).

Based on all the experiments we made the following conclusions.

First, it’s clear that even with the best Generation 3 device it’s close to impossible to identify a gun in low contrast conditions without the IR illuminator.

 

Second, the IR illuminator can be very useful even when there is plenty of light (i.e. half moon). It may change the contrast of the scene and help to detect a gun or other object.

 

It should be noted, that in the case of most night vision devices, turning on the IR means exposing your position. It is visible to the human eye, and looks like a small red dot. N-Vision Optics GT-14 is the only device that we are aware of, whose IR illuminator is completely invisible to the human eye, and can be of a great assistance in any situation.

Third, Generation 1 devices always have to be used with IR illuminator on.

 

 

 

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