How is the tunnel advertisement in the subway realized? Seek science!

You see so many advertisements every day, how many can you remember? In this era of information explosion, we receive overwhelming information every day. Does it dazzle you?

Even on the subway every day, there are advertisements everywhere. You must have seen them.

When you go to work by subway, it is this kind of dynamic advertisement outside the window, with bright colors and strong visual impact, which not only makes you forget the crowded boredom when you take the subway, but also makes you remember the goods advertised.

In addition to the dark tunnel outside the window, you can often see various high-definition brand advertisements. You question: How did this kind of advertisement come from?

In fact, the principle is very simple: the dynamic advertisement of subway tunnel adopts the principle of human visual persistence. Similar to movies in cinemas, every frame of film is different. When the projector plays at an appropriate frame rate, the audience will have a clear and stable dynamic film effect.

Say what? You said it was too complicated to understand? Then Xiaowan will give you an easy-to-understand example.

Do you still remember the kind of hand-turned book animation we watched when we were young? Every page is a static image, and even a few pages are identical images that you feel repeated when you open them, but once you turn the book with your fingers quickly, the picture will "move".

In the same way, the subway tunnel advertisement only combines the speed of the subway and produces this movie-like effect. Taking advantage of this phenomenon, we now think of the moving train as a player, which makes the advertising image in front of passengers have a moving effect, clear and stable.

Dynamic advertisements in subway can be divided into static LED display screen and LED array beam according to display media.

Static LED display screen

Install 400 to 800 display screens continuously on the tunnel wall of 200-800 meters. By limiting the angle of each single picture installed on the tunnel wall, when the train runs at high speed, the pictures installed on the tunnel wall will flicker one by one at a fixed position relative to the passengers, thus making the passengers feel the animation effect. The human eye will see 24 frames per second as continuous, similar to the movies you see in the cinema.

It's just that movies and comics are static and their images are changing; However, the picture of the tunnel advertisement is fixed, and people move with the carriage at high speed.

In order to stabilize the picture, this kind of advertisement usually needs to measure the running speed of subway trains between stations first. Only in the area with stable speed (generally the area with basically constant speed), such as the middle section between two stations, will there be no problem of fast forward or trailing.

The other is LED array beam, and the vertical LED array beam is installed on the inner wall of the tunnel.

LED array beam

This kind of "animation" should be set in the section where the subway speed is relatively stable. When the train is stationary, only the light spots of various colors on each beam can be seen. When the train is moving fast, we can use the principle of "visual persistence" (1/24 seconds) to form a dynamic picture. Form a frame scanning effect similar to TV. If the speed is faster or slower, people on the train will feel that the picture is slowly moving forward or backward.

Of course, some people will ask, are these lights always on in that tunnel? That's not true. The vehicle is driving with information. Before the train runs to the advertising section, the running status of the train will be fed back to the trigger switch of the advertising switch circuit.

In this way, when the train runs to the advertising section, the advertising light will light up and you will see the animation on the train. When the train leaves the advertising section, the trigger circuit receives the information of the train leaving, and the advertising switch is automatically turned off and is in a standby state until the next train arrives.