Normally, we are all looking at the reflected light of the object. According to James Consulting, the sun camera, night vision device and human eye follow the same basic principle: visible light energy will be reflected back after impacting the object, and then reused. The detector receives the reflected light and converts it into an image.
Whether it's an eyeball or a camera, these 'detectors' must receive enough light, otherwise they will not be able to form an image. Obviously, there is no sunlight at night to form reflected light, so nighttime imaging is often limited by starlight, moonlight and artificial light. In this case, these detectors will not work if there is insufficient light.
Thermal imager
Compared with the above detectors, the thermal imager is completely different. Although we call the thermal camera "camera", its essence is the sensor. To understand how they work, the first thing to do is to forget what you are doing. Know everything about camera imaging.
FLIR products use thermal energy to take photos instead of visible light. Thermal energy (also or infrared, heat or energy) and light are part of the electromagnetic spectrum, but cameras that detect visible light do not detect thermal energy. And vice versa.
Thermal imaging cameras (also known as infrared cameras) can detect not only thermal energy, but also small thermal energy differences (contrast) as small as 0.01 ° C, and display gray shades of different shades in black and white video. This may be somewhat It's hard to understand, many people don't understand the concept, so let's take a moment to explain it.
The picture shows a panther taken with an infrared camera.
Everything we encounter in our daily lives, even ice, emits heat. The higher the temperature of the object, the more heat it releases. We call these released heat energy a 'thermal signal'. The thermal signals between adjacent objects are slightly different and will appear prominently on the FLIR thermal imager, regardless of the lighting conditions.
Thermal energy comes from a combination of various sources of heat radiation, depending on what you see at the time. For example, warm-blooded animals (including humans), engines and machinery, whether biological or mechanical, are things that can create their own heat. Other things, such as land, rocks, buoys, vegetation, etc., absorb solar heat during the day and release it at night.
Since the rate at which different materials absorb and release heat energy is different, we believe that it should be the same temperature zone, in fact it is caused by a slight temperature difference. This is why the temperature of logs and water that are continuously immersed in water for several days is still different. , but these are visible to the thermal imager. FLIR products are able to detect these temperature differences and convert them into image details.
Although the above theory sounds quite complicated, modern thermal imaging cameras are very easy to use. The image of the thermal imager is clear and easy to understand, without any training or explanation. As long as you watch TV, you will use the FLIR thermal imager.
The picture shows FLIR ONE Pro
Low light level night vision device
The green images we see in movies and TV come from low-light night vision (NVG) or other devices that use the same core technology. The low-light night vision device amplifies the received small amount of visible light and projects it onto the display. on.
Night vision image display
Cameras made with low-light night vision technology have the same limitations as the naked eye: If there is not enough visible light, it cannot be seen clearly. Any imaging performance that depends on reflected light will be limited by the amount and intensity of reflected light.
At dusk, low-light night vision and other low-light cameras are not very useful, because dusk is too light for them, but it does not provide enough light to be seen with the naked eye. In contrast, thermal imaging cameras do not. Affected by visible light, they give a clear image even against the setting sun. In fact, even if the spotlight is aimed at the camera, it still gives a perfect picture.
Infrared illumination (I2) camera
The I2 camera projects near-infrared light that its imaging sensor can sense and receives reflections from objects. This is possible to some extent, but I2 cameras still need to rely on reflected light for imaging, so they rely on reflections from others. Light night vision cameras have the same limitations: small shooting range, poor contrast.
Image contrast
All of these visible light cameras (such as daylight cameras, low-light night vision devices, and I2 cameras) work by detecting reflected light. However, the amount of reflected light received is not the only factor that determines whether these cameras can be shot clearly. : Image contrast is also important.
If the object being shot is very different from the surrounding environment, the chance of the visible light camera being shot is even greater. If the contrast is not enough, no matter how bright the sun is, there is no way to capture it clearly. The contrast of white objects is very high on a dark background. However, it will be difficult to capture darker objects in the dark background, which is the contrast. The lack of visible light at night, the contrast of the image will naturally decrease, so the performance of the visible light camera will be more affected.
Thermal imaging cameras do not have the above disadvantages. First, thermal imaging cameras do not need to reflect light, they only need heat. Everything in daily life has a thermal signal. This is the use of thermal imaging cameras at night than visible light cameras and even night vision cameras. Better root cause.
In fact, many things that are commonly seen, such as humans, can produce contrast on their own, because things generate heat by themselves, and the difference in heat is contrast. Thermal imagers can effectively capture these differences in heat because of thermal images. The instrument not only uses thermal imaging, but also discerns the difference in heat between objects and presents them as images.
Low-light-level night vision devices have the same disadvantages as daylight and low-light cameras: require enough light and require sufficient contrast to produce an effective image. In contrast, the daytime and night, the thermal imager can be clearly Capture images and contrast. There is no doubt that thermal imaging is the best choice for all-weather imaging!
