How to realize stripe photography? Shoot the hot air flow

Fringe photography is an invention in the 17th century. It records the microscopic world invisible to the naked eye by special means based on aerodynamics. A professor at Pennsylvania State University recently discovered that this ancient technology can develop many new uses, such as preventing infectious diseases and airport security. Without stripe photography, we might never know that a lighted lighter and a burning candle are so beautiful. Fringe photography is a special technique to show the different concentrations in different areas of gas or liquid with colors and shadows. Since its birth, many artists and photographers have been obsessed with the vagaries of light and shadow. However, in the eyes of scientists, stripe photography has always been their good helper, like a microscope, to uncover the secrets of the microscopic world. Professor of aerodynamics Gary? Sehter: We can see a lot of things from the air flow, the shock wave around the bullet, the hot air from your body when you cough, which are all useful for science. Many scientific and technological advances are related to fringe photography. Gary, a professor of aerodynamics at Pennsylvania State University? Sehter has been dealing with stripe photography for 25 years. According to his latest discovery, stripe photography can also help people find the way of germs spreading in the air and find explosives in time during security inspection. Gary? Some scientific research achievements of Sehter have been applied to life. This is the security channel designed by him. The hot air trajectory emitted by each passenger will be recorded and captured when he passes by. The gas contains tiny particles of any object that the passenger has touched. By analyzing its composition, it can be judged whether the passenger has been exposed to explosives. This kind of security gate has been widely used in American airports at present. The simple way is to use a scattered light source, such as a desk lamp, and surround it with a translucent cover, that is, only part of the light passes through. This cover is not a single color, but black and white stripes alternate with each other. Put a heat source in front of it, such as a lighted candle, and the heated air will rise, thus changing the air density around it. At this time, the light passing through the air will deviate. These shifted lights were photographed in the filtered background. Due to the visual principle, only the deviated lights can be seen, and those directly from the candle flame are weakened. The final result will be an image that can show the different density of air, that is, the image of heat distribution around the flame, formed by color technique or black-and-white difference.