The user must first read the manual carefully when using the infrared lamp, especially the precautions to ensure the safety of personal equipment. Check whether the compatibility aspects mentioned above meet the requirements, whether the influencing factors that should be considered are taken into consideration, and if the requirements are not met, the equipment used can be adjusted in time.

Why does the infrared camera have night vision at night?

Generally speaking, any animal and object can emit or reflect infrared rays. Our eyes cannot perceive this kind of light. The night is very "dark". It is just that the human eye can feel very little visible light, but infrared rays do not. While weakening, the infrared camera can feel infrared, it can use the infrared ray emitted by the object to image, the transformed image can be seen by us, so it has the "night vision" function. In addition, some infrared cameras can also emit infrared light to "illuminate" the object being photographed.

What is the range of the infrared camera?

Generally less than 70 meters, small 5--20 meters, if you want to shoot a longer distance, you need to add an infrared probe, the farther you shoot, the more probes, the greater the power

Can the infrared camera distinguish the color of the object?

First, let me talk about the principle of color imaging. Color is composed of electromagnetic waves of different wavelengths. Light is a type of electromagnetic wave. Red light has a longer wavelength and blue light is shorter. Human eyes can only accept red, green and blue. These colors are synthesized by the brain. Infrared and ultraviolet light cannot be seen by the human eye, so there is no way to convert them into corresponding colors. It is said that bees can see ultraviolet light, but I don’t know how it feels.

People invented the infrared camera, but it is difficult to convert infrared rays into colors. In fact, there are some. Thermal imaging cameras convert infrared rays into red, yellow, blue and other colors according to the energy. Blue low temperature, according to Planck’s blackbody radiation principle, different sizes of energy can correspond to different central wavelengths. According to the principle of human eyes to recognize the color of an image, it can also correspond to the color of visible light in this way. It looks very unreal, but it is not as easy to distinguish as black and white images. Black and white infrared images actually use infrared as the light source to see infrared images of objects in the dark.

Therefore, infrared cameras can see colors, but this color is not a true color. Conventional commercial infrared cameras basically do not convert images according to colors, but convert them to black and white images, which makes it easier to distinguish.

To be more precise, infrared cameras should be called infrared enhanced cameras. Since infrared to visible light is a continuous spectrum, as long as the spectrum of the photosensitive element is wide enough, it can be sensitive to light including infrared, so that the photosensitive element increases infrared under the same visible light intensity. The frequency band is equivalent to increasing the sensitivity of the photosensitive element, and in low vision conditions, a clearer image can be obtained. 

The reasons for not using color representation are 2: 1. Because the increased infrared spectrum cannot be represented by colors that humans can perceive, it is better to express through black and white images. 2. In the case of low light conditions, the sensitivity requirement is higher if spectroscopic sensing is performed again. The mixed spectrum is used to shoot according to the light intensity, and the sensitivity of the photosensitive element is increased in disguise, so that the camera can take darker images.

I. Overview

In the TV monitoring system project, infrared lights were rarely used in the past, but nowadays the rate of social crime has not only increased, infrared light plays a more prominent role in night surveillance, not only treasury, oil depot, armory, library, cultural relics, prisons And other important departments are adopted, and are also used in general monitoring systems. Infrared cameras are even used in TV surveillance projects in residential quarters. This shows that people's requirements for TV monitoring system engineering are becoming more standardized and higher. More and more important places require continuous monitoring for 24 hours.

The method of realizing night vision can use conventional visible light illumination, but this method not only cannot conceal, but also exposes the monitoring target. Hidden night vision surveillance currently uses infrared camera technology. Infrared camera technology is divided into passive infrared camera technology and active infrared camera technology. 

Passive infrared camera technology uses the principle that any object has infrared light emission above absolute zero (-1273°C). Since the infrared light emitted by the human body and heating objects is relatively strong, and the red light emitted by other non-heating objects is very weak, night monitoring can be realized by using a special infrared camera. Passive infrared camera technology is not used in night vision systems because of the high cost of equipment and the inability to reflect the surrounding environment. 

Active infrared camera technology uses a special "infrared lamp" to artificially generate infrared radiation, which is invisible to the human eye but can be captured by ordinary cameras, and radiates "illumination" the scenery and environment. It uses ordinary low-light CCD black and white cameras or uses "daytime" The color camera that automatically turns black and white at night or the "infrared low-light color camera" can feel the infrared light reflected from the surrounding environment, so as to realize the night vision function.

Second, the principle characteristics of infrared cameras

Light is an electromagnetic wave, and its wavelength range is from a few nanometers (1nm=10-9m) to about 1 millimeter (mm). What the human eye can see is only part of it. We call it visible light. The wavelength of visible light ranges from 380nm to 780nm. The wavelength of visible light is divided into red, orange, yellow, green, blue, blue, and violet from long to short. The wavelength is shorter than violet light. It is called ultraviolet light, and the wavelength longer than infrared light is called infrared light.

Infrared lamps are divided into semiconductor solid light emitting (infrared emission diode) infrared lamps and thermal radiation infrared lamps according to their infrared light radiation mechanism. In general, infrared lamps using infrared emitting diodes are mainly used in the market. The principle and characteristics of the infrared lamps are introduced as follows: the luminous 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 GaAs) to make a PN junction, and a forward bias is applied to inject current into the PN junction to excite infrared light. The spectral power distribution is the center wavelength of 830~950nm, and the half-peak bandwidth is about 40nm. It is a narrow band distribution, which is the range that can be felt by ordinary CCD black and white cameras. Its biggest advantage is that it can be completely free of red storms (using 940-950nm wavelength infrared tube) or only weak red bursts (red storms are visible red light) and long life. The emission power of infrared light-emitting diodes is expressed by irradiance μW/m2. Generally speaking, its infrared radiation power is proportional to the forward working current, but when it is close to the maximum rated value of the forward current, the temperature of the device rises due to the heat consumption of the current and the light emission power decreases. 

If the infrared diode current is too small, it will affect its radiant power, but if the working current is too large, it will affect its life and even burn the infrared diode. In response to this situation, FTV FI-930C and FI-970C fully considered this problem in the design, using high-efficiency light-emitting diodes, built-in heat dissipation system in the camera, so that the camera can work stably for 25,000 hours!

Third, the choice and use of infrared cameras

The most important issue in the selection of infrared light is the complete set of infrared light and camera, lens, protective cover and power supply. At present, most cameras and infrared projectors are separated in the market, so we must consider all the equipment uniformly when designing the plan. Should we choose a black-and-white camera with an infrared light, or a color-to-black-and-white camera? There are also considerations for installation methods and waterproofing. Generally speaking, the CCD sensor used by the black and white camera has a wide light-sensitive spectral range. The light-sensitive spectrum not only includes the visible light region, but also extends to the infrared region. It can be clearly imaged on the CCD sensor by using the auxiliary infrared lamp. 

The light-sensitive spectrum of the camera is only in the visible light region, so it is not suitable for infrared light bulb irradiation photography; day and night dual-purpose cameras use two CCDs for switching or use a CCD sensor, and the digital circuit can also be used to achieve infrared light bulb irradiation photography, but there is The black and white illuminance is too high or has disadvantages such as adverse effects on the color. In addition, there are integrated infrared cameras, which combine cameras, lenses, protective covers, infrared lights, etc., typical products such as FI-930C and FI-970C of Fu Shi Kang. These two use The high-quality aluminum shell, through a one-time molding production process, makes the product's waterproof level reach IP55, which can be used indoors and outdoors. Due to the integrated design, the difficulty of construction and debugging is naturally reduced.

With the rapid development of infrared night vision systems, the number of infrared lamp manufacturers and suppliers will increase, but infrared products are not as easy as some people think, and the conditions in technology, testing equipment and other aspects are also different. I hope users can compare them more. Choose carefully.

The user must first read the manual carefully when using the infrared lamp, especially the precautions to ensure the safety of personal equipment. Check whether the compatibility aspects mentioned above meet the requirements, whether the influencing factors that should be considered are taken into consideration, and if the requirements are not met, the equipment used can be adjusted in time.