We look at the world through the eyes of a mantis cancer: the near infrared range

And you thought we only know how to do teapots ? Nah

We are all accustomed to the fact that the flowers are red, black surfaces do not reflect light, Coca-Cola is opaque, a hot soldering iron cannot be illuminated as a light bulb, and fruits can be easily distinguished by their color. But let's imagine for a moment that we can see not only the visible range (hee-hee), but also near infrared. Near-infrared light is not at all what can be seen in a thermal imager . It is rather closer in visible light than to thermal radiation. But it has a number of interesting features - often completely opaque in the visible range, objects are perfectly illuminated in infrared light - an example in the first photo.
The black surface of the tile is transparent to IR, and with the help of a camera, in which the filter is removed from the matrix, you can see a part of the board and a heating element.

For a start - a small digression. What we call visible light is just a narrow band of electromagnetic radiation .
Here, for example, I put such a picture from wikipedia:

We just see nothing but this small part of the spectrum. And the cameras that people make are initially castrated to make the photograph similar to the human vision. The camera matrix is capable of seeing the infrared spectrum, but this feature is removed by a special filter (it is called Hot-mirror), otherwise the pictures will look somewhat unusual for the human eye. But if you remove this filter ...

Camera

Experimental made a Chinese phone, which was originally intended for review. Unfortunately, it turned out that his radio part is cruelly buggy - he either receives or does not receive calls. By itself, I did not write about him, but the Chinese did not want to send a replacement or pick up this one. So he stayed with me.
We disassemble the phone:

We take out the camera. Using a soldering iron and a scalpel, carefully separate the focusing mechanism (above) from the matrix.

On the matrix should be a thin glass, possibly with a greenish or reddish tint. If it is not there - look at the part with the "lens". If not there, then most likely everything is bad - it is sprayed onto a matrix or on one of the lenses, and removing it will be more problematic than finding a normal camera.
If it is - we need to remove it as carefully as possible without damaging the matrix. I cracked it, and I had to blow fragments of glass from the matrix for a long time.
')
Unfortunately, I lost my photos, so I'll show you a picture of irenica from her blog , which did the same thing, but with a webcam.

This is a piece of glass in the corner - just a filter. There was a filter.

Putting it all back, considering that if the gap between the lens and the matrix changes, the camera will not be able to focus properly - you will have either a short-sighted or a far-sighted camera. It took me three times to assemble and disassemble the camera in order to achieve the correct operation of the autofocus mechanism.

Now you can finally assemble the phone, and start exploring this new world!

Paints and substances

Coca-Cola suddenly became translucent. Light from the street penetrates through the bottle, and even objects in the room are visible through the glass.

The cape of black turned pink! Well, except for buttons.

The black part of the screwdriver also brightened. But on the phone this fate befell only the ring of the joystick, the rest is covered with another paint, which does not reflect the IR. Just like the plastic docking station for the phone in the background.

Tablets from green turned to lilac.

Both chairs in the office also turned from gothic-black to incomprehensible colored ones.

Faux leather remained black, and the fabric turned pink.

Ryukzak (he is in the background of the previous photo) has become even worse - he has almost all become purple.

Like a bag for a camera. And the cover of the e-book

The stroller from blue turned into the expected purple. And the retroreflective stripe, clearly visible in an ordinary camera, is not at all visible in IR.

Red paint, as close to the part of the spectrum we need, reflecting red light, captures a part of the IR. As a result, the red color brightens noticeably.

And this property has all the red paint that I noticed.

Fire and temperature

The smoldering cigarette looks like a very bright spot in the IR. People stand at night at a bus stop with cigarettes - and their tips illuminate their faces.

A lighter, the light of which in an ordinary photograph is quite comparable with the background illumination in IR mode, blocked the pathetic attempts of street lamps on the street. The background is not even visible in the photo - the smart camera worked out the change in brightness, reducing the exposure.

When warming up, the soldering iron glows like a small light bulb. And in the mode of maintaining the temperature has a soft pink light. And they say that soldering is not for girls!

The burner looks almost the same - well, except that the torch is a little further (at the end the temperature drops pretty quickly, and at a certain stage it stops shining in visible light, but still shines in IR).

But if you heat a glass rod with a torch, the glass will glow in the IR quite brightly, and the rod will act as a waveguide (bright tip)

And the stick will glow for a long time and after the cessation of heating

A hairdryer at a thermoair station in general looks like a flashlight with a mesh.

Lamps and light

The letter M at the entrance to the subway is much brighter - it still uses incandescent bulbs. But the sign with the name of the station almost did not change the brightness - it means there are fluorescent lamps.

The yard looks a bit strange at night - lilac grass and much lighter. Where the camera in the visible range can no longer cope and is forced to increase the ISO (grain in the upper part), the camera without an IR filter suffices light with a margin.

This photo turned out to be a funny situation - the same tree is lit by two lamps with different lamps - on the left a NL (orange street) lamp and on the right an LED one. The first one has an infrared radiation spectrum, and therefore the foliage below it looks light-violet in the photo.

And the LED does not have IR, but only visible light (therefore, the lamps on LEDs are more energy efficient - energy is not spent on the emission of unnecessary radiation, which a person will not see anyway). Therefore, foliage has to reflect what is.

And if you look at the house in the evening, you can see that different windows have a different shade - some are bright purple, while others are yellow or white. In those apartments whose windows glow purple (blue arrow) still use incandescent bulbs - the hot coil shines uniformly throughout the spectrum, capturing both the UV and IR ranges. In the entrances, energy-saving lamps of cold white light (green arrow) are used, and in some apartments - fluorescent lamps of warm light (yellow arrow).

Sunrise. Just sunrise.

Sunset. ~~Just sunset.~~ The intensity of sunlight is not enough for the shadow, but in the infrared range (maybe because of the different refraction of light with a different wavelength, or because of the permeability of the atmosphere), the shadow is visible perfectly.

Interesting In the corridor, one lamp died and the light was barely, and the second one was not. In the infrared light, on the contrary - a dead lamp shines much brighter than a living one.

Intercom. More precisely, the thing next to him, which with cameras and lights, which is included in the dark. It is so bright that it can be seen on an ordinary camera, but for an infrared it is almost a searchlight.

The backlight can also be turned on during the daytime by closing the light sensor with your finger.

Highlighting CCTV. The camera itself did not have a backlight, so it was thrown ~~out of shit and sticks.~~ It is not very bright, because it was shot in the afternoon.

Nature

Hairy kiwi and lime green are almost the same in color.

Green apples turned yellow, and red - bright lilac!

White peppers turned yellow. And the usual green cucumbers - some kind of alien fruit.

Bright flowers have become almost monotonous:

The flower is almost not different in color from the surrounding grass.

And the bright berries on the bush became very difficult to see in the foliage.

Yes that berries - even the multi-colored foliage became monophonic.

In short, choose the fruit of their color will not work. We'll have to ask the seller, he has a normal vision.

But why is the photo all pink?

To answer this question, we will have to recall the structure of the camera's matrix. I again stole the picture from Wikipedia.

This is the Bayer filter - an array of filters painted in three different colors, located above the matrix. The matrix perceives the entire spectrum equally, and only filters help to build a full-color picture.
But the infrared spectrum filters pass unequally - blue and red more, and less green. The camera thinks that instead of infrared radiation, ordinary light strikes the matrix and tries to form a color picture. In photos, where the brightness of the infrared radiation is minimal, ordinary colors still make their way - in the photos you can see shades of colors. And where the brightness is high, for example, in the street under the bright sun, the infrared hits the matrix exactly in the proportion that filters pass and forms pink or purple color, filling all other color information with its brightness.
If you take pictures with a filter mounted on the lens, the proportion of colors is different. For example, like this:

I found this picture in the community ru-infrared.livejournal.com
There's also a bunch of pictures taken in the infrared. The greens on them are white because the BB is set just by the foliage.

But why do plants turn out so bright?

In fact, this question consists of two - why the greens look bright and why the fruits are bright.
The green is bright because in the infrared part of the spectrum absorption is minimal (and the reflection is maximum, as the graph shows):

Guilty of this is chlorophyll. Here is its absorption spectrum:

Most likely this is due to the fact that the plant is protected from high-energy radiation, adjusting the absorption spectra in such a way as to obtain energy for existence and not to be dried out from too generous sun.

And this is the radiation spectrum of the sun (more precisely, that part of the solar spectrum that reaches the earth's surface):

Why does fruit look bright?

The fruit in the peel often do not have chlorophyll, but nevertheless - they reflect IR. Responsible for this substance, which is called epicuticular wax - the very white coating on cucumbers and plums. By the way, if you google “white bloom on plums”, then the results will be anything, but not this.
The meaning of this is about the same - it is necessary to preserve the color, which can be critical for survival, and not let the sun dry the fruit on the tree. Dried prunes in the trees is, of course, excellent, but a little does not fit into the life plans of the plant.