What videos are there in the subway tunnel? Can I still watch videos by subway?

At present, dynamic advertisements in subway are divided into static LED display screen and LED array beam according to display media.

1 static LED display

It is necessary to install 400 to 800 pictures continuously on the tunnel wall of 200 to 800 meters. By limiting the viewing 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 flash one by one at a fixed position relative to the passengers, thus making the passengers feel the animation effect.

To make this kind of advertisement, it is necessary to record or shoot the advertisement content first, and then decompose it into coherent images with a fixed frame rate through related software, and then splice these images into continuous images, and then put the advertisement images on the LED display screen in turn through the control center.

It should be noted that in order to stabilize the picture, this kind of advertisement usually needs to measure the running speed of subway trains between stations first, and only in areas with stable speed (generally areas with basically constant speed), such as the middle section between two stations, will there be problems of fast forward or trailing.

2 LED array beams

Vertical led array light columns are installed on the inner wall of the tunnel, each light column is nearly 1 m high, and nearly 600 LEDs are distributed on it as a row of pixels, and the interval between two illuminators is about1.2m..

When the train is stationary, only the light spots of various colors on each beam can be seen. When the train is running fast, a dynamic picture can be formed by using the principle of "visual persistence". Different from the static LED display screen, the LED array beam is not only suitable to be placed in the area where the train runs at a constant speed, but also can be placed anywhere in the subway tunnel. So how did it do it?

It turns out that it uses synchronous sensors to sense the running speed of trains in real time. When the train passes by, the synchronous sensor correspondingly drives the luminous frequency of the LED array beam. The slower the train speed, the higher the luminous frequency, and the faster the train speed, the lower the luminous frequency. In this way, the colorful activity advertisement picture is presented to the passengers through the flickering picture.