1. The emergence of LED spherical screens is a product that has emerged in response to one of the needs of people, that is, the pursuit of new and strange things. In the early years, if a large flat LED display appeared on the square, people would be surprised: such a big TV! Now these "big TVs" can no longer satisfy people's curiosity. If one day, an outdoor LED spherical screen with a diameter of 5 meters appears in the square, it will be a very popular product. Therefore, it is an unconventional and popular product. All the deficiencies caused by the use of flat* frequency sources to play on the three-dimensional spherical surface will be accommodated*, just as distorted photos taken with a wide-angle lens or fish-eye camera are accepted by people.
2. The playback principle of the LED display is: the control system of the LED display (controller + computer) transmits the image source played on the computer screen to the flat LED display for display.
Almost all image sources in the world are flat. If the flat image source is sent to a three-dimensional LED spherical screen for display without processing, it is almost impossible. Fortunately, the ball is round. It is impossible for any individual audience to look at every corner of the LED ball screen at the same time. He can only see a small part of the ball surface. This is also related to the diameter of the ball screen. If the diameter of the ball screen is sufficiently large, the effective effect is probably only about one-sixth of the surface area of the ball (due to the viewing angle), and five-sixths of it is not visible. It is not what they are concerned about, because these five-sixths are on the back, right, left, right, top, and bottom of the ball, respectively. In this way, the playback methods that can be used are: 1). Play six different image sources in six different areas of the sphere. 2). Play 3 different image sources in the three areas of the sphere (such as left and back, top right, front and bottom). 3). Play the 2 image sources in two areas (rear right front, upper left lower). Of course, you can also play a flat image source on the entire sphere like a watermelon rind LED spherical screen.
3. The resolution design of the LED spherical screen is the same as that of the flat LED display, that is, it is closely related to the viewing distance of the LED display. The general experience is P2.5, viewing away from 2.5m, P6 viewing beyond 6m, such as P20 outdoor The screen, when viewed from a distance of 20m, is also true in actual use. This is a relatively vague choice, which is qualitative rather than quantitative. Its basis is as follows:
LED display screens are the same as computer display screens. The images they display are composed of pixel points, and each pixel point is composed of red, green, and blue color elements. There is a certain distance between pixels, and this distance is called the dot pitch PH. Suppose the resolution of the computer display is 1024×768, the computer display has 1024 pixels in the horizontal direction and 768 pixels in the vertical direction. It is enough to express a sufficiently detailed image.
If the physical size of the computer display is 300mm in the vertical direction, then the pixel pitch on the computer display is PH=300/768=0.39mm, and Ph is an important parameter of any digital display.
We measured: the distance between the human eye and the computer display is D=450mm, then the angle between two adjacent pixels and the human eye is θ, then the equation θ=Arctg0.39/450 (1)
If we place the computer display 30,000mm away from the operator and replace the computer display with an LED display or LED spherical screen, the distance between the human eye and the LED display or LED spherical screen is 30,000mm. It can be seen that, in order to ensure that the perception of image pixels remains unchanged (or the resolution remains unchanged), the angle of θ should also remain unchanged. *One that needs to change is that Ph has changed.
According to equation (1), there is an equation: θ=Arctg0.39/450=ArctgPh/30,000+450, from which we find Ph=26mm, that is, we will design the pixel pitch of the LED spherical screen to be 15~20mm. At that time, the clarity of the ball screen is sufficient and reasonable. At this time, the image clarity of the LED ball screen we see from 30 meters away is the same as what we see in front of the computer. If the distance between the person and the LED spherical screen is other values, the Ph value can be calculated by referring to the above method.
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