I don’t know about you, but I’ve always wondered: what would the world look like if the RGB color channels in the human eye were sensitive to a different wavelength range? After rummaging around, I found infrared flashlights (850 and 940 nm), a set of IR filters (680-1050 nm), a black and white digital camera (no filters at all), 3 lenses (4mm, 6mm and 50mm) designed for photography in IR light. Well, let's try to see.

We have already written on the topic of IR photography with the removal of the IR filter on the hub - this time we will have more opportunities. Also, photographs with other wavelengths in RGB channels (most often capturing the IR region) can be seen in posts from Mars and about space in general.

These are flashlights with IR diodes: 2 left ones at 850nm, the right one at 940nm. The eye sees a faint glow at 840 nm, the right one only in complete darkness. For an IR camera they are dazzling. The eye seems to retain microscopic sensitivity to near-IR + the LED radiation comes with lower intensity and at shorter (=more visible) wavelengths. Naturally, you need to be careful with powerful IR LEDs - if you are lucky, you can unnoticed get a burn to the retina (as with IR lasers) - the only thing that saves you is that the eye cannot focus the radiation to a point.

Black and white 5 megapixel noname USB camera - on Aptina Mt9p031 sensor. I spent a long time shaking the Chinese about black and white cameras - and one seller finally found what I needed. There are no filters in the camera at all - you can see from 350nm to ~1050nm.

Lenses: this one is 4mm, there are also 6 and 50mm. At 4 and 6 mm - designed to work in the IR range - without this, for the IR range without refocusing, the pictures would be out of focus (an example will be below, with a conventional camera and IR radiation of 940 nm). It turned out that the C mount (and CS with a flange length different by 5mm) was inherited from 16mm movie cameras of the beginning of the century. Lenses are still actively produced - but for video surveillance systems, including by well-known companies like Tamron (a 4mm lens from them: 13FM04IR).

Filters: I again found a set of IR filters from the Chinese from 680 to 1050 nm. However, the IR transmittance test gave unexpected results - these do not seem to be bandpass filters (as I imagined), but rather different "densities" of color - which changes the minimum wavelength of light transmitted. Filters after 850nm turned out to be very dense and require long shutter speeds. IR-Cut filter - on the contrary, it transmits only visible light; we will need it when shooting money.

Visible light filters:

IR filters: red and green channels - in the light of a 940 nm flashlight, blue - 850 nm. IR-Cut filter - reflects IR radiation, that's why it has such a cheerful color.

Let's start shooting

Panorama during the day in IR: red channel - with a filter at 1050 nm, green - 850 nm, blue - 760 nm. We see that trees reflect the very near IR especially well. Colored clouds and colored spots on the ground were caused by the movement of the clouds between frames. Individual frames were combined (if there could be an accidental camera shift) and stitched into 1 color image in CCDStack2 - a program for processing astronomical photographs, where color images are often made from several frames with different filters.

Panorama at night: you can see the difference in color between different light sources: “energy efficient” - blue, visible only in the very near IR. Incandescent lamps are white and shine throughout the entire range.

Bookshelf: Almost all normal objects are virtually colorless in IR. Either black or white. Only some paints have a pronounced “blue” (short-wave IR - 760 nm) tint. LCD screen of the game “Well, wait a minute!” - does not show anything in the IR range (although it works for reflection).

A cell phone with an AMOLED screen: absolutely nothing is visible on it in IR, as well as the blue indicator LED on the stand. In the background, nothing is visible on the LCD screen either. The blue paint on the metro ticket is IR transparent - and the antenna for the RFID chip inside the ticket is visible.

At 400 degrees, the soldering iron and hair dryer glow quite brightly:

Stars

It is known that the sky is blue due to Rayleigh scattering - accordingly, in the IR range it has much lower brightness. Is it possible to see stars in the evening or even during the day against the sky?

Photo of the first star in the evening with a regular camera:

IR camera without filter:

Another example of the first star against the background of the city:

Money

The first thing that comes to mind to verify the authenticity of money is UV radiation. However, banknotes have a lot of special elements that appear in the IR range, including those visible to the eye. We have already written briefly about this on Habré - now let’s see for ourselves:

1000 rubles with filters 760, 850 and 1050 nm: only individual elements are printed with ink that absorbs IR radiation:

5000 rubles:

5000 rubles without filters, but with lighting of different wavelengths:
red = 940nm, green - 850nm, blue - 625nm (=red light):

However, the infrared money tricks don't end there. The banknotes have anti-Stokes marks - when illuminated with IR light of 940 nm, they glow in the visible range. Photography with a regular camera - as you can see, the IR light passes a little through the built-in IR-Cut filter - but because... The lens is not optimized for IR - the image does not come into focus. Infrared light appears light purple because Bayer RGB filters are IR transparent.

Now, if we add an IR-Cut filter, we will only see luminous anti-Stokes marks. The element above “5000” glows the brightest, it is visible even in dim room lighting and backlighting with a 4W 940nm diode/flashlight. This element also contains a red phosphor - it glows for several seconds after irradiation with white light (or IR->green from the anti-Stokes phosphor of the same label).

The element just to the right of “5000” is a phosphor that glows green for some time after irradiation with white light (it does not require IR radiation).

Summary

Money in the IR range turned out to be extremely tricky, and you can check it in the field not only with UV, but also with an IR 940nm flashlight. The results of shooting the sky in IR give rise to hope for amateur astrophotography without traveling far beyond the city limits. It's not warm yet, but it's no longer light.
How to obtain an infrared image using a regular camera. How to make an IR filter from scrap materials. Specialized cameras. Difficulties when shooting and how to get around them. Selection of lenses, cameras and filters.
Interesting scenes in the infrared range.

Using live examples of infrared images, we will try to process them together. We will get ready-made solutions for image processing and together we will analyze how these solutions work.

THEORETICAL PART

Understanding of infrared, visible and ultraviolet radiation. Difference between infrared and thermal radiation.

Infrared radiation was discovered in 1800 by the English scientist W. Herschel, who discovered that in the spectrum of the Sun obtained using a prism, beyond the red light boundary (i.e., in the invisible part of the spectrum), the temperature of the thermometer increases. It was then proven that this radiation obeys the laws of optics and, therefore, has the same nature as visible light.

Fig.1 Decomposition into solar radiation spectrum

On the opposite side, beyond the violet band of the spectrum, there is ultraviolet radiation. It is also invisible, but it also warms up the thermometer a little.

Far infrared radiation (the longest wavelength) is used in medicine in physiotherapy. It penetrates the skin and heats the internal organs without burning the skin.

Mid-infrared radiation is recorded by thermal imagers. The most popular applications of thermal imaging cameras are for detecting heat leaks and non-contact temperature monitoring.

Rice. 2. Thermal imager (mid-infrared)

We are most interested in near (the shortest wavelength) infrared radiation. This is no longer thermal radiation from surrounding objects at room temperature, but not yet visible light.
In this frequency range, objects heated to a noticeable red glow emit quite strongly. For example, a nail heated red-hot on a gas stove flame in infrared light is bright white (Fig. 3). Colder areas (the redness of which is imperceptible in the visible spectrum) remain dark in IR.

Rice. 3 Near IR

It is this range of radiation that “works” when objects are heated in the sun or under incandescent lamps. And this same radiation is absorbed by “thermal” car windows and energy-saving double-glazed windows at home.
Its most popular applications are remote controls (Fig. 4), infrared surveillance cameras with infrared illuminators.
At one time, data transmission using the IrDA standard was popular. The same infrared port in phones and laptops.

Rice. 4. Remote control

In digital, as well as film photography, the sensitivity of the camera to infrared radiation is undesirable. It leads to color distortion - black velor jackets look blue, and the saturation of red is selectively lost.
Therefore, in modern cameras they fight it in every possible way using a wide variety of methods. However, there is still residual sensitivity, albeit very small.

Differences between black and white and infrared imaging.

Filters that make color photography look like infrared are quite popular on the Internet. However, they cannot work correctly because the color image does not contain information about the reflectivity of the materials in the infrared spectrum. Roughly speaking, they cannot distinguish between a green car and green foliage and make all green objects in the frame appear white. In the same way, everything blue becomes black.
In the same way, infrared photography does not work with a simple red filter, no matter whether it is film or digital.

How to get an infrared image

In order to obtain a true infrared image, it is necessary, in the simplest case, not to allow visible radiation to pass into the lens, so that the camera’s residual sensitivity to infrared radiation forms the image.

Infrared films

In the case of film photography, this is ensured by the use of special films Kodak High Speed Infrared HIE, Konica Infrared 750 and the most popular - Ilford SFX 200. However, film is not enough; you also need to install a filter that cuts off visible light. Otherwise, the film turns into regular black and white panchromatic film with increased grain. A completely uninteresting combination.
Infrared film is very demanding on storage conditions - it is strongly recommended to store it in the refrigerator. It is necessary to load film into the camera in complete darkness, because the tail of the film acts as a light guide and exposes up to half of the film. Plus, frame counters in film cameras also expose the film. Under no circumstances should you expose the film when scanning luggage at the airport, and it is almost impossible to do this with modern security measures - the security service rears up and urgently asks to show what is in the box.
After exposure, the film must be developed using the classic black and white process in pitch darkness and preferably in a metal tank.
In summary, film infrared photography is more of a heroic activity than a practical one.

Digital cameras

In digital photography everything is much more interesting. In most popular digital cameras, the matrix has a residual sensitivity to the infrared range sufficient to photograph in the sun with a shutter speed of several seconds.

Rice. 5. Infrared photography. Canon EOS 40D, F8, 30”. Slide film filter.

Although digital camera sensors are sensitive to infrared radiation, their sensitivity to visible light is thousands of times greater, so to take IR photography you need to block visible light with a special filter.
For example, Canon EOS 40D and 300D cameras in the summer sun required a shutter speed of 10...15 seconds at an aperture of F5.6 and a sensitivity of ISO 100. Under similar conditions, the Nikon D70 allowed working with a shutter speed of ½...1 second (which indicates a significantly weaker IR filter in the camera).
If you are not afraid of long exposures, then it is quite possible to work in this mode - simply install an infrared filter in front of the lens and take photographs from a tripod.
The disadvantage of this solution is not only long exposures, but also the inability to crop the image - nothing is visible in the optical viewfinder. You always have to use LiveView, and not all cameras have it.

Cameras with retractable infrared filter (NightVision)

At one time, when digital SLR cameras had not yet gained the popularity they have today, Sony DSC-F707/717/828 cameras enjoyed authority among photographers.

Fig6. Cameras Sony DSC-F717/828/707

Their special feature was the shooting mode Night Shot– in it, a filter that absorbs infrared radiation was removed from the camera matrix. This made it possible to install a special filter in front of the lens that transmits only infrared radiation and obtain an honest infrared photograph with relatively short shutter speeds. Albeit with a lot of automation limitations, this made it possible to photograph portraits in the IR range.
There is a legend that the Canon EOS 20Da and Canon EOS 60Da cameras designed for astrophotography are adapted for infrared photography, but this is not true. They have a different Low-Pass filter design and increased sensitivity in the red range. However, they are also insensitive to the infrared range.

Modification of the camera for infrared photography.

If the capabilities of a regular camera with a filter seem insufficient and you want to take infrared photographs with short shutter speeds, then you can remove the infrared-cutting filter (Hot Mirror) from the camera and get a camera with a fairly high sensitivity to the IR range. In ordinary visible light, the camera will stop working normally - the colors will be constantly distorted, and this can only be dealt with by installing the Hot Mirror filter on the lens. Therefore, for shooting in the IR range, they often use an old camera, which has already served its purpose and is not so bad to break.
And since interference in the camera has begun, you can directly place an infrared filter directly in front of the matrix. The advantages of this solution are that the image is again visible in the viewfinder, and you no longer need to place an infrared filter in front of the lens. And since you don’t need a filter, you can use lenses with different filter thread diameters.
At home, it is theoretically possible to change the filter in front of the matrix, but in practice it is more profitable to give the camera to a specialist for modification - the result will be much better, and the camera will not be broken. Again, a knowledgeable person will test the camera’s autofocus for infrared photography and make adjustments if necessary.

Infrared filters

Shooting in the infrared range almost always requires the use of infrared passing filters. Filters that do not transmit visible light, but are transparent to infrared radiation.
And in this matter, the simplest assistant is photographic film: developed color film is transparent in the IR range. This means that exposed and developed negative or simply developed slide film will turn out to be black in the visible range, but transparent in the infrared.
By the way, it is the IR transparency of film that film scanners with automatic dust removal use. They take an additional photo in the infrared range - the dust remains visible against the background of the transparent film. And this is a ready-made mask for removing dust.

Fig.7. Slide film

If so, then you can cut a circle of the required diameter from a suitable film and place it between the protective filter and the lens. If the effect is not enough, you can add several layers of film. The picture will lose a little contrast and sharpness, but the infrared component will become obvious.

Fig.7A Slide film and IR radiation

You can also look for black CD-R discs. They were popular for recording music, but recently, with the decline in popularity of CDs, they have become difficult to find. If you remove the cover from such a disc, you will get a black disc that is transparent in the IR range.

Fig.8. Black CD.

There are many options for off-the-shelf IR filters available. The most popular filter in Russia is the Hoya R72 filter. It blocks radiation shorter than 720 nanometers, which is exactly the limit of visible light. The Schneider B+W 093 filter is slightly less popular - it also completely blocks visible radiation.
Filters Schneider B+W 092 and Cokin P007 do not completely block visible radiation, so the picture is only slightly colored. Slide film shows an intermediate result, so it has to be stacked in several layers.

Lenses

One light filter is not enough for shooting - you need something else to form the image. The difficulty with infrared photography is that the lens will be used in an application that is not normal for it. The wavelength of light is at least a little longer than the visible one, which means that the refraction of light will be less (remember the prism from Fig. 1), which means that the scale of the picture will change. The lens will become slightly longer focal length. At the same time, a whole scattering of problems arises, which have a stronger impact in some places and less in others. Let's take a closer look at them

Focusing

If the lens is pointed at infinity in visible light, then in the IR range it will be pointed a little closer. Front focus will appear. But there is also a good side to this error - it is stable and it is enough to simply turn the focusing ring to a certain angle. It is for this purpose that Soviet lenses (for example, Jupiter-37A, Jupiter-9, Helios 44M-8 and some others) have an additional red mark R. To focus correctly in IR, you must first focus in visible light, and then turn the focus ring to the mark R.
In modern lenses, this mark is quite rare, and in zoom lenses its position depends on the focal length. Therefore, you should not particularly trust the usual phase detection autofocus of SLR cameras. You can get around the problem either by using Live View and focusing on contrast, or focusing manually, controlling sharpness on the screen. If the camera does not have Live View, then you can simply aperture the lens further and thereby hide the focusing error in the depth of field.

Fig.9 Infrared mark on the focus scale.

On prime lenses, you can set this mark yourself by taking several shots and choosing the position with maximum sharpness. The position of this mark does not depend on the focusing distance and aperture, so it is enough to simply draw it once and use this correction in the future.

Quality of enlightenment

The antireflective coating on lenses is several layers of thin films, at the border of which a light beam is reflected, interferes with the main beam and significantly reduces the intensity of reflection. That is, each coating layer is designed for a specific wavelength. However, for infrared radiation there may not be its own layer of antireflection. Therefore, some lenses begin to “catch hares”, show quite strong flares and lose microsharpness. And some work normally in the infrared range.

Field unevenness, Hot-Spot

Another problem with infrared optics is reflections at the junctions of the lenses in the lens. With especially multi-lens lenses, they sometimes fold so poorly that a bright spot of illumination appears in the middle of the resulting image - a Hot-spot (Fig. 10). The effect is more pronounced at closed apertures and at short focal lengths. If you remember that the matrix often has a hot-miror filter that reflects infrared radiation back into the lens, the picture turns out to be completely bleak.

Fig.10 Hot-spot

It's a shame that this effect most often occurs with ultra-wide-angle zoom lenses. These are precisely the lenses that produce the most interesting infrared images.

Glare

Most lenses are not designed for infrared photography. Therefore, blackening of internal surfaces, protection against reflections and the location of drives inside the lens can lead to strong glare when direct sunlight enters the lens. You have to use deep lens hoods, shoot from the shadows, or take several pictures with different highlights and assemble mosaic panoramas from them.

Rice. 11 Glare

All of the listed features largely depend on the type of lens and may vary slightly depending on the model or camera. There are reviews on various lenses on the Internet, tables describing suitability and problems that arise with lenses. You can find them by searching for “lenses suitable for infrared photography.” But this does not mean that pictures with other lenses will not work out at all. They may require some additional attention - for example, covering them from the sun, or framing them a little differently. But in my experience there was not a single lens that was completely unsuitable.
The only case where IR photography is completely unsuitable is for cameras with a lens set to the hyperfocal distance (cameras without autofocus). In their IR range, the sharpness zone moves forward, and there is simply nothing to correct the focus. But such cameras are practically no longer found in the form of separate cameras. They can only be found in the most inexpensive phones or as the front camera on tablets. I don’t think that shooting in the IR range with the front camera of a tablet can make even the slightest sense.

Practical part

Infrared photography is good because it is unusual and different from ordinary photography. Because familiar objects begin to look different. Therefore, it makes sense to focus on stories that highlight this difference.
In the IR range it is possible to obtain a picture with very high contrast. It is somewhat reminiscent in contrast to a black and white photograph behind a rich red K-8X filter, but the picture is even more contrasting. Infrared photography is mainly good in landscapes. Both urban and natural landscapes. With an abundance of sky, foliage and space.

Fig. 12 Gradient on the sky in backlight

The sky looks interesting. A clear sky appears black because it does not reflect infrared radiation. Cirrus clouds, in turn, reflect solar and scattered infrared radiation very well, so they look bright white against a black sky. But thunderclouds, containing large raindrops and large volumes of water, already absorb IR. That's why thunderclouds look black. The picture turns out to be similar to the sky taken through a thick red filter, but much more contrasting. At the same time, even the smallest clouds are visible in the IR range, almost invisible in the visible range.

Fig. 13 Water and sky in IR

In our latitudes there is practically no dry and cloudless sky. There is almost always a slight haze in the sky and therefore the sky becomes very light when backlit. This interferes with shooting 360-degree panoramas, but looks quite natural in wide-angle shots, even with the sun in the frame, as shown in Figures 11 and 12.
If you hide the sun, for example, behind trees, as is done in Figure 12, then you get rid of two problems at once - both glare from direct sunlight and gradients in the sky.
The water surface looks very unusual in the IR range (Figure 13). Water absorbs IR radiation better than visible radiation and appears much darker in the IR range than in the visible. However, the reflectivity is slightly better than in visible light. These factors together create the feeling of a dark mirror.
Tree foliage and grass are greatly transformed in the IR range. They become very light, almost white. Which, however, is quite logical - the leaves should not heat up in the sun, and the IR receives the largest amount of solar energy. Tree trunks and dried vegetation absorb infrared radiation and appear much darker. This feature of IR images is used in aerial photography for agricultural purposes to highlight areas with dead vegetation.
Photos with lots of foliage look like winter landscapes. Flowers in IR can appear either light or dark.
Insects most often turn out to be very dark - since they cannot maintain their body temperature, they benefit from absorbing the sun's heat as well as possible.

Rice. 14 Flowers in IR

The city landscape is also fraught with unexpected twists - the brightness of paint pigments in infrared light can differ greatly from visible light, and dark windows of buildings turn out to be transparent (or mirrored - dark, as in photo 13). All this, combined with the contrasting sky and white foliage, makes the landscape unusual and therefore interesting.
It's not easy with IR portraits. Lips are equal in brightness to the skin of the face, eyebrows and eyelashes turn pale. The skin appears significantly lighter than in the visible range. Volume is lost. The eyes look very dark against the background of lighter skin.
In people with fair skin, blood vessels protrude (Fig. 15). Cosmetics also add uncertainty - you can never guess in advance whether lipstick, eye shadow or foundation will be dark or light in IR. Dyed hair also becomes unpredictable, but most often becomes dark. Undyed hair becomes lighter.
Inexpensive plastic sunglasses often become transparent, and clothing changes brightness. All this makes the result unpredictable when shooting large portraits, but shooting full-length, and even in combination with a landscape, can diversify a photo shoot. Due to the distance of the figures, faces can be hidden, but the unusual contrast and rendition of tones will remain.
If you are going to have an infrared portrait photo shoot, then it is advisable to check all the products used for adequacy before the makeup application - it will be very sad if the powder that the makeup artist applies to the forehead and cheeks suddenly turns out to be deep black in the infrared range. If it is possible to persuade a model not to wear makeup before an IR photo shoot, then it is better to do so. It’s easier to draw a cut-off pattern during processing than to try to correct all the errors that appear in IR. But if you are unlucky and makeup in IR does not work, then you can limit yourself to general plans, and make the missing large portraits in visible light.

Rice. 15 Portrait in IR.

Fig.16 Channel mixer

After this, the sky will not be red, but blue, and the foliage will no longer be blue.
All that remains is to equalize the white balance, and Image -> Auto Color does an excellent job of this.
These two operations can be written into a separate Action and in the future simply call it, rather than searching for tools in the menu.
All that remains is to use curves and masks to bring the picture to perfection and, if necessary, convert the image into black and white mode in any way convenient for you.

Rice. 17 Result of replacing blue and red channels

Bibliography

Hayman R. Light filters. – M.: Mir, 1988. – 216 p.
Soloviev S.M. Photography in infrared rays. – M.: Art, 1957. – 90 p.
Joe Farace Complete Guide to Digital Infrared Photography. – Lark Books, 2008. – 160c.
Cyrill Harnischmacher Digital Infrared Photography. – Rocky Nook, 2008. – 112 p.
Deborah Sandidge Digital Infrared Photography (Photo Workshop). – Wiley, 2009 – 256c.
David D. Busch David Busch's Digital Infrared Pro Secrets. - Course Technology PTR, 2007 – 288c.

In general, in fact, any digital camera is capable of working as an image intensifier (electronic optical converter) for a zero-generation NVD (night vision device) (these night vision devices use active infrared illumination of the area), because the camera matrices themselves receive not only visible, but and the infrared spectrum too. Excess light is removed using light filters (in our case, an infrared filter is used) and this is done so that the image that the camera produces corresponds to how the human eye perceives it. In cheap cameras, the infrared filter is very weak or may not exist at all; to check, you can shine the remote control (remote control), for example, into the camera of a mobile phone. Based on this, you can remove the infrared filter from an ordinary webcam; at the same time, it is advisable to increase the sensitivity of the webcam and get rid of image noise in low-light conditions.

Removing the infrared filter from the webcam

Let's look at the process of dismantling the infrared filter, using the Logitech Webcam C120 webcam as an example. This model is one of the most convenient and optimal cameras for our topic.

First you need to disassemble the case, remove the casing in the front hemisphere, remove the rubber plug that covers the place where the fastening screw is located and then unscrew the screw itself. To perform these operations you will need at least a thin Phillips screwdriver (it would be better to use a clock screwdriver), you will need to remove the plug by picking it with some sharp object, although this can also be done with your fingernails.

After unscrewing, the chamber is disassembled into two halves - hemispheres; to do this, you need to pull them away from each other in opposite directions from the central seam. You can remove the standard stand if it is not needed in the future, remove the light conductor from the indicator LED and remove the button, which is located on the back of the camera.

Now you need to pull out the board on which the lens is attached from the grooves. Then remove the focus ring from the lens, and the lens itself is unscrewed from the matrix housing. Put everything you took aside for now, now you need to get to the main thing - the matrix.

To remove the casing from the matrix, you need to unscrew two screws located on the back of the board. The casing around the perimeter is firmly glued to the board, so you need to remove it very carefully, but at the same time you need to put in some effort. After you remove everything, it is advisable to put the casing and board with the matrix aside for a while, so as not to accidentally damage the matrix.

Now let's move on to the main step. The infrared filter is glued to the casing from the inside; it is better to remove it with glasses, because the infrared filter is made of glass and small pieces of glass can fly into your eyes when you separate the casing from the filter.

That's all, the night vision camera is done. Now all that remains is to attach the casing in its place (when installing, pay attention to the keys that are located on the casing and the board - protrusions and holes, respectively; their alignment ensures the correct location of the casing). Screw the lens into the housing, connect the camera and check its functionality.

Now you need to place the camera in a convenient case (you can use standard ones if its shape and size suit you) and place it in the place you need, for example above the door, connecting the camera wire to the computer.

In addition to the fact that the IR camera itself is less sensitive to poor lighting and is therefore better suited than an ordinary camera for use as a security camera, it has a number of other interesting features:

The first and main feature follows from the very essence of an infrared camera; it perceives infrared radiation, which means that infrared illumination invisible to the naked eye (zero generation principle - NVD) will work well with such a camera.

And the second feature of an infrared camera is that some materials (synthetics, for example) are permeable to infrared radiation. Also, in infrared light, security features on banknotes are visible. Just for fun, the veins on the human body look funny when taken with an infrared camera.

As you can see, making an IR night camera from a simple webcam is very easy and cheap. Such alterations provide very interesting opportunities both from the point of view of practice and from the point of view of simple curiosity and entertainment. You can also create an infrared illumination module, this module can be used for night vision in conjunction with a regular mobile phone, the mobile phone camera can recognize the infrared spectrum, thus creating a real mobile night vision device.

A homemade infrared camera in your hands will be very useful when you meet Bigfoot or an alien from another planet in the forest at night. It would be nice to shoot an ordinary real interesting night picture with an IR camera. An IR camera will also not hurt if you just decide to become a private detective.

Thus, an IR camera is needed in many life situations, so it is definitely recommended to make one. Of course, with your own hands. If you make it according to the instructions we offer (tested in practice), then it will allow you to take fairly high-quality pictures in the dark, even if there is almost no light.

We collect materials:

– digital camera type Olympus FE-47 14MP;

– Congo Blue color filter;

– 36 powerful infrared LEDs;
– 3 carbon resistors 5% 220 Ohm 0.25 W pk/5;
– breadboard 276-149A with 371 holes;
– battery “Krona” 9 V:
– isolated connector for battery;
– body with dimensions 4x2x1" (1" = 1 inch = 2.54 cm);
– bolt 1/4-20x1/2", nut and washer (in the bolt designation the first number is the thread diameter in inches, the second is the number of turns per 1 inch, i.e. the thread pitch, the third is the length of the bolt shaft in inches) .

Let's start making the device

Unscrew the screws from the camera body (on both sides).

Remove the panels and body from the camera. We put all the screws aside, labeling each of them so that we know exactly which one to screw in when assembling.

Then we dismantle the display.

We continue disassembly: remove the main board of the camera and free the CCD matrix and the back side of the optics.

Remove the infrared filter between the CCD matrix and the lens. This procedure may differ for different camera models. It can cause a lot of trouble for the owners of some models, but for our model the whole problem is solved by simply shaking the camera. The photo on the right shows the IR filter separately.

Now we cut out six to eight squares from the light filter to the size of the IR filter, stack them and insert them into the camera in place of the IR filter. We assemble the camera and put the housing on it. To test, turn on the camera and make sure that it works: everything is visible on the display in the infrared spectrum.

The camera is ready for use, next we’ll work on the backlight unit. We have prepared a 4x2x1 case for it." On its lid we mark points for drilling holes: we make three lines of marks at equal distances from each other. We make the distances between adjacent marks in a line the same - about half a centimeter.

We drill holes with a diameter of half a centimeter in the marked places.

We drill another hole on the side wall of the case to attach the bolt: anywhere on the side wall in the middle of the height. We insert the prepared bolt into this hole from the inside of the housing and secure it with a nut and washer.

Using sharp scissors, cut off about half a centimeter from the sides of the breadboard. We get a long narrow strip.

We arrange all the LEDs on the breadboard so that their cathodes and anodes are lined up in separate rows, and the LEDs themselves fit exactly into the holes drilled for them on the housing cover.

After this, we insert the LEDs into the corresponding holes on the block cover from the inside and turn the entire structure over.

We bend the first row of LED legs in any one direction and solder them together along one line. We do the same with all the other rows of LEDs. After this, we connect three rows of anodes together (in the photo they are connected with a black wire).

We solder a resistor to all three rows of cathodes. We solder the free contacts of these resistors together to the red wire of the battery connector. We solder the second (black) wire from the battery connector to one of the rows of anodes. We connect the battery.

Place the battery inside the case, close the lid and screw it on.

The backlight block is ready.

Screw it into the mounting hole on the bottom wall of the camera.

Our homemade infrared camera is ready, you can go hunting in the dark night for sensational pictures.

In conclusion, we also note that the IR camera can be used to remotely identify a drunk person. The future24 website reports that Greek researchers have developed techniques that make it possible to distinguish a sober person from a drunk person based on the results of analyzing a photograph of his face with an IR camera. One method analyzes temperature fluctuations: in a drunk person, the areas of the face around the mouth and nose are usually warmer than other parts of the face.

It is assumed that these techniques can find application in entertainment centers, airports and other places where the presence of intoxicated persons is undesirable.

No less interesting articles

As a continuation of my recent note, I want to talk about the simplest way to convert a regular webcam into a so-called night vision camera - capable of sensing the infrared range of the spectrum.

What is an infrared night vision camera

In fact, any digital camera can act as an image intensifier (electron-optical converter) for a zero-generation night vision device (NVD) (such NVGs use active IR illumination of the area), since the camera matrices themselves perceive not only the visible, but also the IR spectrum. “Excess” light is cut off using light filters (in this case, an IR filter) and this is done so that the image produced by the camera corresponds to what is perceived by the human eye. By the way, in cheap cameras the IR filter is weak or may be completely absent - to check, you can shine the remote control, for example, into the camera of a mobile phone. Therefore, by removing the IR filter you can turn a regular webcam into a night vision camera, at the same time increasing the overall sensitivity of the webcam and getting rid of image noise in low-light conditions

Removing the IR filter from the webcam

I’ll look at the process of dismantling the IR filter using a webcam as an example. Logitech Webcam C120. There is a good one on the Internet with descriptions (in English) of ways to remove IR filters from web cameras of the main sizes. Even if a specific camera model is not there (like mine, for example), it is useful to find the nearest similar one and familiarize yourself with its structure; this will be useful in the future when disassembling your camera. Attention— not every camera can be painlessly deprived of a filter — .

The first step is to disassemble the case - by removing the casing from the front hemisphere, removing the rubber plug that covers the seat of the mounting screw and unscrewing the screw itself. To perform these operations, you will need at least a thin Phillips screwdriver (a clock screwdriver is best); it is convenient to remove the plug by picking it with some sharp object, although it is quite possible to get by with your fingernails.
After unscrewing, the chamber is disassembled into two halves, hemispheres, for which you need to pull them in different directions from the central seam. In this case, you can remove the standard stand if it is not needed in the future, as well as remove the light conductor from the indicator LED and remove the button located on the back of the camera.
Now you need to remove the board with the lens attached to it from the grooves. After which the focusing ring is removed from the lens, and it itself is unscrewed from the matrix housing. Let’s put everything we’ve filmed aside and get down to business with the main thing—the matrix itself.
To remove the housing from the matrix, you need to unscrew the two screws located on the back of the board. The casing around the perimeter is glued to the board, so you need to remove it carefully, but with some force. After removing the skin, it is better to also put the board with the matrix aside so that the matrix is not accidentally damaged.
Let's move on to the main step. The IR filter is glued to the casing from the inside, I personally couldn’t dismantle it reversibly - I just had to knock it out with a sewing needle and clean out the remains (it’s better to do this with glasses - the IR filter is glass and small pieces of glass can fly into the eye).
That's it, the night vision camera is ready! All that remains is to put the casing in place (when installing, pay attention to the keys located on the casing and the board - protrusions and holes, respectively, the alignment of which ensures the correct location of the casing). We screw the lens into the housing, connect the camera and .

Now you just need to enclose the camera in a convenient housing (you can also use standard ones if its size and shape suit you) and place it in the right place - for example, above the front door, connecting the camera wire to the computer. And enjoy your self-assembled video surveillance system!

Why else might an infrared camera be useful?

In addition to the fact that the infrared camera itself is less sensitive to poor lighting and is therefore better suited for use as a security camera than a regular one, it has several other interesting features:

The first and main thing, which follows from the very essence of the IR camera, is that it perceives IR radiation, which means that IR illumination invisible to the naked eye (the same principle of zero-generation NVGs) will work perfectly with such a camera. Uncle Liao suggests