The grayscale of LED display is also known as the color scale or gray scale, refers to the brightness of the degree of light and darkness, generally speaking, the higher the grayscale, the richer the color of the LED display, the more delicate the picture, easier to show rich details.
LED display grayscale level
LED display grayscale level refers to the LED display with the same level of brightness from the darkest to the brightest brightness level can be distinguished between.
“Gray level” refers to a variety of colors in the darkest and brightest colors, with different changes in the color class, generally speaking, the gray level in 14 bits (bit) or more, that is, at least 16,384 kinds of color class or more, for high-performance LED display.
If the number of gray levels is not enough, there will be a lack of color levels or gradient color gradient is not smooth enough, and can not fully show the color of the film. Therefore, It will reduce the LED display effect. Some low performance LED display in 1/500s shutter, can be detected under the obvious color distribution, if we will increase the shutter speed, such as 1/1,000s or 1/2,000s, the situation will be more obvious.
The grayscale level depends mainly on the number of digital-to-analog (A/D) conversion bits of the system. Of course, the system’s video processing chip, memory and transmission system must provide the appropriate number of bits to support.
Grayscale level Includes no gray scale, 8 levels, 16 levels, 32 levels, 64 levels, 128 levels, 256 levels, 1024 levels, etc., the higher the grayscale level of the LED display, the richer the color, the more colorful; on the contrary, the display of a single color simple changes.
At present, the common LED display mainly uses 8-bit processing system, that is, 256 (28) levels of gray scale.In the In other words, there are 256 kinds of brightness changes from black to white. Using RGB three primary colors can constitute 256x256x256 = 16777216 colors. That is usually referred to as 16 trillion colors. International brands mainly use 10-bit display processing system, that is, 1024 levels of gray, RGB three primary colors can constitute 1.07 billion colors.
What affects the LED display refresh frequency and gray level?
We know that the LED display several core components, such as LED switching power supply, LED driver chip, LED lamp beads, etc., for the LED display refresh frequency and gray level, LED driver chip directly determines the LED display in the visual refresh frequency, gray level performance.
In the current LED driver chip, the highest new technology for the “ScrambledPWM (S-PWM) technology”, S-PWM technology is to improve the traditional pulse width modulation (PWM) technology, which will be an image of the on-time dispersed into a number of shorter on-time, in order to increase the overall rate of visual updates.
The new generation of LEDs will be able to provide a more efficient visualization of the image. Further explanation, the new generation of LED driver chip built-in S-PWM technology, can be originally counted once per frame way, the average dispersion into a number of counts, and each dispersion of equal parts, can be maintained before the original not dispersed On/Off ratio.
The S-PWM technology provides different counting modes, thus increasing the image refresh rate up to 64 times. By switching to S-PWM to increase the video refresh rate, the visual refresh rate can be easily increased by 64 times with a low-level clock (e.g., 5 MHz) and can reach over 4,800 Hz.
Compared with the general video visual refresh frequency capacity of at least 10 times higher, but also to avoid the generation of high-frequency electromagnetic interference (EMIissue), over-voltage surge (Overshoot) and under-voltage surge (Undershoot) problems.
S-PWM driver chip LED display, with a digital camera high-speed shutter for the camera, still does not appear horizontal black scan lines and color block distribution. Its visual refresh frequency, gray level performance, far beyond the use of traditional switching-type driver chip LED display.
The higher the grayscale of LED display, the better?
Although the gray scale is the determining factor of the number of colors, but it does not mean that the larger the better without limitations.
Because the resolution of the human eye is limited, and then the system to deal with the increase in the number of bits will be involved in the system video processing, storage, transmission, scanning and other aspects of the change, the cost increases dramatically, the cost-effective rather than decline. Generally speaking, civil or commercial grade products can be used 8-bit system broadcast grade products can be used 10-bit system.
How to do grayscale transformation?
Gray scale non-linear transformation refers to the gray scale data in accordance with empirical data or some kind of arithmetic non-linear relationship for transformation and then provide to the display.
Since LED is a linear device, it is different from the non-linear display characteristics of traditional displays. In order to make the LED display effect can be consistent with the traditional data source without loss of gray level, generally in the LED display system will be done at the back of the nonlinear transformation of grayscale data, after the transformation of the number of bits of data will be increased (to ensure that no loss of grayscale data).
Now some China top LED control system suppliers provide 4096 level grayscale or 16384 level grayscale or higher Gray scale after the nonlinear transformation of the gray space size.
4096 level is the use of 8-bit source to 12-bit space nonlinear transformation technology, 16384 level is the use of 8-bit to 16-bit nonlinear transformation technology. By 8-bit source to do nonlinear transformation, the converted space is definitely larger than 8-bit source.
It is usually at least 10 bits. As with grayscale, this parameter is not as big as better, generally 12 bits can do enough transformation.
Conclusion
The higher the grayscale level of the LED display, the richer the color of the screen it shows, the more colorful. On the contrary, if the gray level is low, the picture reduce color, but the high LED display gray level products will be higher than the low gray products, so it will correspondingly increase the purchase cost, so with which gray level of the key is your application.
GDHANHENG, as China’s top LED screen manufacturer, we can provide cost-effective high grayscale LED displays based on your actual project. If you need it, please feel free to contact us.
