”Big bags, small bags, please go through security check!” Security check is always an essential step when you travel by high-speed rail, airplane, or subway. I wonder if you have ever been interested in this security check machine. What can the staff see on the screen? How do they quickly identify the items in the suitcase? Today, let the editor reveal this secret for you.This means that walk through metal detector It is the weather vane of the industry and can bring people great self-confidence. https://secuzoan.com/
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How does the security inspection machine work?
Generally speaking, the machine that conveys and inspects luggage is called an X-ray luggage inspection machine. As the name suggests, the security inspection machine uses X-rays to inspect luggage.
X-rays are short-wavelength electromagnetic waves that can penetrate objects. The penetration of X-rays varies depending on the thickness, density and material of the object.
Everyone should know that X-rays in hospitals are also used by doctors. The penetration rate of X-rays varies according to the density of the structure and tissue. The penetration rate is high in loose areas and low in dense areas. The bones of the human body are denser than the skin and flesh tissue. Therefore, when X-rays are irradiated to the human body, the outline of the bones will be displayed more clearly on the screen.
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The same is true for the security inspection machine that checks luggage. The penetration rate of X-rays on different objects is different. When the suitcase passes through the security inspection machine, the X-rays penetrate the suitcase and display the outlines of different objects on the display screen.
At this time, some friends may feel confused: X-ray imaging should be black and white, so why can security inspectors identify different objects so quickly?
This question really hits the nail on the head. If you have ever looked at the security check display screen, you will find that the image on it is in color, not black and white.
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Normally, the color of the image formed by X-rays on the film is indeed black and white, just like the X-ray photos in the hospital. The reason why a color image appears on the security screen is that the computer calculates and converts the projection intensity of the X-rays. This is also to make it easier for security personnel to quickly distinguish different objects in a short period of time.
Normally, orange represents organic matter such as liquids and sprays; blue represents metals and various controlled knives; and heavy metals or lead, which can completely absorb X-rays, will be displayed in black.
Now you should know why the staff will immediately notice and ask you to take out a small pair of scissors in your suitcase; and the water in your backpack will also be asked to take out and drink a sip.