What Is an IR Camera?

Infrared camera: The visible light that can be seen by human eyes is red, orange, yellow, green, cyan, blue, and purple in order of wavelength from long to short. Light with a shorter wavelength than violet light is called ultraviolet light; light with a longer wavelength than red light is called infrared light, and the human eye cannot see the infrared light. Because digital cameras use a CCD to sense all the light, the resulting image is very different from the image that our naked eye sees only visible light. In order to solve this problem, the digital video camera is equipped with an infrared filter between the lens and the CCD, and its function is to allow infrared light in a certain band to pass, absorb or reflect visible light and ultraviolet light. At present, most infrared cameras use LED infrared light emitting diodes as the main material of infrared cameras.

What human eyes can see

Principle characteristics of infrared camera

Light is an electromagnetic wave. Generally, people divide infrared light into three parts: near, middle and far infrared. Near-infrared refers to a wavelength of 0.75 to 3.0 microns; mid-infrared refers to a wavelength of 3.0 to 20 microns; far-infrared refers to a wavelength of 20 to 1000 microns.

Light is a

Infrared lamps are classified into semiconductor solid light (infrared emitting diode) infrared lamps and thermal radiation infrared lamps according to their infrared light radiation mechanism. We introduce its principle and characteristics as follows:

A light emitting body is composed of an infrared light emitting diode matrix. The infrared emitting diode is made of a material with high infrared radiation efficiency (commonly used gallium arsenide) to make a PN junction, and a forward bias is applied to inject a current into the PN junction to excite infrared light. The spectral power distribution is a center wavelength of 830 to 950 nm and a half-peak bandwidth of about 40 nm. It is a narrow-band distribution and is a range that can be experienced by ordinary CCD black and white cameras. Its biggest advantage is that it can be completely free of red storms (using infrared tubes with a wavelength of 940 to 950 nm) or only weak red storms (red storms have visible red light) and long life.

The emission power of an infrared light emitting diode is expressed in terms of irradiance W / m2. Generally speaking, its infrared radiation power is directly proportional to the forward working current. Many manufacturers, irresponsibly, arbitrarily increase the transmission power in order to obtain an increase in infrared distance, which is actually a short-sighted behavior that is promoted by seedlings, and eventually causes a high degree of glare in the image Whitening and reduced life

When the voltage crosses the forward threshold voltage (about 0.8V), the current starts to flow, and it is a very steep curve, indicating that its working current is very sensitive to the working voltage. Therefore, the working voltage is required to be accurate and stable, otherwise the radiated power will be exerted and its reliability will be affected. The increase of the radiated power with the ambient temperature (including the increase of the ambient temperature caused by its own heating) will reduce its radiated power. Infrared lamps, especially long-range infrared lamps, heat consumption is an issue that should be paid attention to when designing and selecting.

The angle at which the radiation intensity is 50% of the maximum is called the half-intensity radiation angle. The radiation angle of the infrared light emitting diodes of different packaging process models is different.

Halogen bulb with filter

The irradiation distance is long and the power is large, but the energy loss is also large. Because of the addition of a filter, most of the visible light is filtered out and converted into thermal energy. Therefore, the infrared lamp has a short life and many after-sales service problems;

Laser tube

The irradiation distance is the longest, but the angle is small. If the angle is increased, the distance will be relatively short due to the limited energy. It can be seen that the application of laser tubes in the security industry is very contradictory;

LED light-emitting diode

This kind of application is relatively extensive, the life of a single tube is very long, but if there are more tubes, the current will be larger, the heat will go up, and the life will be shortened. At the same time, high currents can cause fire hazards. However, these disadvantages can be avoided.

LED infrared light products are divided into two categories with red burst and no red burst.

Some red-explosive products use infrared led emission tubes with a wavelength of 850nm. During use and close observation, the infrared lamp will emit dark red light.

No red explosion products use infrared led emission tubes with a wavelength of 940nm. In use, the surface of the infrared lamp does not have any light, so it is more concealed.

The sensitivity of the same camera at 850nm is 10 times better than that at 940nm. Therefore, 850nm infrared lamps with slight red storms have higher efficiency and should be the first choice for infrared lamps. ^[1]

Infrared camera at

The infrared camera on the Chinese market mainly uses day-to-night conversion through infrared filters, that is, opening the filter during the day to block infrared rays from entering the CCD, so that the CCD can only sense visible light; under night vision or poor lighting conditions The filter stops working and no longer blocks infrared rays from entering the CCD. The infrared rays are reflected by the object and enter the lens for imaging.

However, in practice, infrared cameras often have a clear daytime picture, but the picture becomes blurred under infrared light. This is because the wavelengths of visible light and infrared light (IR light) are not the same. Different wavelengths will cause different positions of the focal plane of the image, resulting in virtual focus and blurred images.

The IR lens uses the latest optical design methods, special optical glass materials, and special advanced films and materials to eliminate focal plane shifts in visible and infrared light.

The special optical glass material solves the problem of clear imaging of the infrared camera infrared, so that the light from the visible region to the infrared region can be imaged at the same focal plane position to achieve a clear image; special film technology allows infrared light to Possible transmission; Multi-layer coating can also minimize the occurrence of ghosting and flashing under backlight conditions, and can obtain relatively high-contrast quality pictures even under adverse conditions such as backlight.

The IR lens has a wide range of applications. It can be used for special infrared applications or as an ordinary lens.

As the saying goes, there will be a market when there is a demand, and soon there will be professional suppliers of 850NM and 940NM wavelength infrared lamps on the market. There is no photoresistor on the infrared lamp board. The LEDs are all turned on as soon as the power is turned on. As for the infrared lamp that is turned on 24 hours a day, how long it can be used, readers can imagine. The application of photoresistors quickly solved the problem of infrared cameras. The infrared light can be turned on or off according to the brightness of the ambient light. This application increased the life of the infrared camera by more than half at the time. This was also the earliest "day and night" Dual-use infrared camera. " Regarding the evolution of infrared cameras, it is necessary to trace the origin of infrared cameras. The earliest E-2001 infrared camera used 12 remote control infrared lights. As for the infrared wavelength, it was not known at the time.

After the introduction of color CCD chips, infrared cameras faced another problem. Severe color cast during the day!

In order to solve this problem, it was applied on the CCD.

The most important issue in the selection of infrared cameras is infrared lights and cameras, lenses, protective covers,

Generally speaking, the radiant power of its infrared lamp is proportional to the forward working current.

The infrared integrated camera is very popular, the main reason is that the cost is low and the installation is convenient, but in the process of using it, we will always encounter some problems that we ca nt think of. The following are in production and sales

Part of the power consumed by the lamp is converted into effective light energy, and part is converted into

Cameras generally require 24 hours of uninterrupted work. Therefore, proper maintenance of the camera can extend the life of the camera and ensure the stability of the camera's image effects. Pay attention to the following points.

· Pay attention to the stability of the camera voltage, otherwise it will affect the effect of the image and even cause the camera to be damaged;

· Check the wire for damage and aging frequently to avoid abnormal situations;

· Try to avoid direct sunlight or strong light for a long time to avoid damage to the camera CCD;

· The camera needs to be cleaned frequently, such as cleaning the dust on the surface of the camera's casing frequently, and try not to open the casing. If it needs to be opened, power off first;

· Establish camera files for easy inspection and testing in the future.

Category: Infrared Camera

Summary: using 24 x 8 lights

Infrared distance: 80-150m

Image sensor: 1/3 "Sony Super HAD CCD

First, when installing an infrared camera, the first thing is to choose the right lens. It is said that a good horse is equipped with a good saddle. In order to improve the sensitivity of infrared cameras to infrared lights and scenes, lenses with a large amount of light should be selected as much as possible, and when using an automatic aperture or a motorized variable lens, the driving level of the aperture should be set as wide as possible. The main reason is that when the focal length of a general lens is increased, the light flux will be relatively reduced. Pay special attention when choosing an infrared light.

Second, the optional power supply of the infrared lamp should meet its minimum electrical power as much as possible, and often the power is insufficient and the irradiation distance is insufficient.

3. When using it, you must also consider the degree of reflection of the scene being photographed. Because the infrared light used by the infrared camera has the same characteristics as visible light, such as reflection and refraction, it should be considered if there is no good reflective environment around the target scene. Distance margin.

4. In order to better solve these problems, some manufacturers also use infrared LED + infrared color CCD technology when producing infrared cameras. The introduction of these products can solve the needs of infrared cameras at night. Nowadays, the application of infrared night vision cameras is more common, and it is more suitable for use at night or when the line is insufficient. ^[3]