LED display gray level and gray principle

  Grayscale is grayscale, which refers to how many shades a color can have from light to dark. For digital display technology, gray scale is the determining factor for the number of displayed colors. Generally speaking, the higher the gray level, the richer the displayed colors, the finer the picture, and the easier it is to express rich details.

    Grayscale imaging principle

The gray level mainly depends on the number of digital-to-analog conversion bits of the system. Of course, the system’s video processing chip, memory and transmission system must provide corresponding bit support. Currently LED displays are mainly used:

    First, 8-bit processing system, that is, 256 (2 to the power of 8) level gray. The simple understanding is that there are 256 brightness changes from black to white.

    Second, 10-bit processing system, that is, 1024 (2 to the power of 10) level gray. The simple understanding is that there are 1024 brightness changes from black to white.

    Third, 12-bit processing system, that is, 4096 (2 to the power of 12) level gray. The simple understanding is that there are 4096 kinds of brightness changes from black to white.

    Fourth, 14-bit processing system, that is, 16384 (2 to the power of 14) level gray. The simple understanding is that there are 16,384 brightness changes from black to white.

    How to identify the brightness level of LED display

     The brightness discrimination level refers to the brightness level of the image that can be distinguished by the human eye from the darkest to the whitest. As mentioned earlier, the gray level of the display is very high, which can reach 256 or even 1024. However, due to the limited sensitivity of the human eye to brightness, these gray levels cannot be fully recognized. In other words, the gray eyes of many adjacent levels may look the same. And the eye resolving power varies from person to person. As for the display screen, the more the level of human eye recognition is, the better, because the displayed image is for people to see after all. The more brightness levels the human eye can distinguish, the larger the color space of the display, and the greater the potential for rich colors. The brightness discrimination level can be tested by special software. Generally, the display can reach a level of 20 or above, which is a better level.

     Now some domestic control system suppliers’ so-called 4096-level grayscale or 16384-level grayscale or higher refers to the grayscale space size after nonlinear transformation. Level 4096 is a non-linear transformation technique using 8-bit source to 12-bit space, and level 16384 is a non-linear transformation technique using 8-bit to 16-bit. The 8-bit source is used for non-linear transformation, and the space after conversion must be larger than the 8-bit source. Usually at least 10 digits. Just like grayscale, this parameter is not as large as possible, generally 12 bits can do enough conversion.

     What brightness requirements does the ambient brightness have on the screen?

     The general brightness requirements are as follows:

    (1) Indoor:> 800CD / M2

    (2) Semi-indoor:> 2000CD / M2

    (3) Outdoor (sit south and north):> 4000CD / M2

    (4) Outdoor (sit north and south):> 8000CD / M2

    What are the brightness requirements of red, green and blue in terms of white composition?

    Red, green, and blue contribute differently to white color. The root cause is that the retina of the human eye perceives light of different wavelengths differently. After a lot of experimental tests, the following approximate ratios are obtained for reference design:

    The simple red-green-blue brightness ratio is 3: 6: 1

    The precise red-green-blue brightness ratio is: 3.0: 5.9: 1.1

    In summary, it is not difficult to see that the grayscale and brightness of LED display screens are related to each other and have their own differences. Neither the grayscale nor the brightness is better.