Disclosure of Invention
The invention aims to provide a MiniLed display screen brightness adjusting method which accords with human eye visual characteristics.
The technical scheme for solving the technical problems is as follows:
the MiniLed display screen brightness adjusting method conforming to the visual characteristics of human eyes comprises the following steps:
step 1, determining a maximum brightness Level (level_Max) in the current adjusting process and a minimum brightness Level (level_Min) in the current adjusting process, wherein the corresponding maximum display brightness is level_Max×N, the minimum display brightness is level_Min×N, and the corresponding PWM high-Level pulse counts are level_Max×N×M and level_Max×N×M respectively; wherein N is the proportion coefficient of PWM duty ratio and display screen brightness, M is the proportion coefficient of PWM high level pulse count and brightness;
step 2, obtaining a fitted brightness curve corresponding to the brightness adjustment curve in the current adjustment process according to a gamma2.2 curve mapping algorithm, and further obtaining PWM high-level pulse counts corresponding to each brightness level after fitting;
and step 3, determining the adjusting frequency corresponding to each brightness level in the adjusting process, and setting PWM high-level pulse count to adjust the brightness backlight of the display screen according to the adjusting frequency and the PWM high-level pulse count corresponding to each brightness level.
Further, in the step 3, the adjusting frequency is set to 80Hz corresponding to the stage of 1% -30% of brightness, the adjusting frequency is set to 50Hz corresponding to the stage of 31% -80% of brightness, and the adjusting frequency is set to 30Hz corresponding to the stage of 81% -100% of brightness.
Further, N is 10.
Further, M is 15.
Further, the gamma2.2 curve mapping algorithm formula is:
PwnCnt=L×M;
wherein: pwmCnt is the PWM high level pulse count corresponding to the fitted brightness level, L_temp is the brightness presented by the corresponding brightness level, and L is the rounded value of L_temp.
The beneficial effects of the invention are as follows: the method of the invention can accord with the visual characteristics of human eyes on the perception of brightness, gradually and smoothly adjust the brightness of the MiniLed display screen, jitter can not occur in the brightness adjusting process, and the human eyes perceive that the brightness is smooth in transition, so that a better visual effect is presented.
Description of the drawings
Fig. 1 is a schematic view of a brightness adjustment curve from 1% to 100% before and after fitting.
Detailed Description
The principles and features of the present invention are described below with reference to the drawings, the examples are illustrated for the purpose of illustrating the invention and are not to be construed as limiting the scope of the invention.
In the invention, the MiniLed display screen uses a singlechip chip to control the brightness through PWM, the brightness level corresponds to the PWM duty ratio, the brightness is in linear proportion to the PWM duty ratio, the proportion coefficient is N, and the high-level pulse count and the brightness proportion coefficient of the PWM are designed in a targeted manner. Namely, the brightness adjustment level is 1% -100%, and the corresponding display screen presents brightness as follows: brightness level×n, PWM high level pulse count is: brightness level x N x M.
The maximum value (level_max×n) and the minimum value (level_min×n) of the brightness present in the current adjustment process are calculated from the adjusted brightness Level. And (3) calculating a brightness value to be mapped for each point under the curve state of gamma2.2 by fitting the brightness adjusting curve of the section according to an algorithm, and setting PWM high-level width counting.
gamma2.2 curve mapping algorithm:
PwnCnt=L×M
rounding and rounding the display brightness L_temp to obtain brightness L, wherein L×M is the PWM high level count PwmCnt to be set.
Wherein:
PwmCnt is the pulse count of the high level setting PWM counter.
L_temp is the brightness presented by the corresponding level.
L is a rounding value for l_temp.
N is the proportion coefficient of PWM duty ratio and display screen brightness.
M is the high level pulse count and brightness proportionality coefficient of PWM.
Level is the brightness Level to be set.
level_Min is the minimum brightness Level in the current adjusting process; if the current action is to increase the brightness, the brightness level of the current display is the brightness level, and if the current action is to decrease the brightness, the brightness level is the target brightness level.
level_Max is the maximum brightness Level in the current adjusting process; if the current action is to increase the brightness, the target brightness level is obtained, and if the current action is to decrease the brightness, the current brightness level is obtained.
When the backlight adjusting effect is observed on the MiniLed display screen used in the invention and the same brightness adjusting frequency (50 Hz) is used, the change of low brightness is easier to be perceived, the feeling of unsmooth brightness adjustment exists, and the perception of the change of high brightness stage is not obvious. In this regard, the brightness adjustment frequency at the low brightness stage of 1% -30% is 80Hz, and the adjustment frequency at the stage of 81% -100% is 30Hz. The brightness adjusting effect is observed, the fixed adjusting frequency is compared, and different frequencies are used, so that the visual effect of human eyes is greatly improved.
The invention defines that N is 10 and M is 15 on a MiniLed display screen, namely the brightness of the display screen is 1000nit when the brightness level of the display screen is 100, the corresponding PWM duty ratio is 100%, and the PWM high-level pulse count is 15000.
When the brightness level needs to be adjusted from 1% to 100%, the following brightness transition conditions are implemented, and the following conditions are shown in table 1:
TABLE 1
According to the above data, the brightness adjustment curves adjusted from 1% to 100% before and after fitting are shown in the following fig. 1, and it can be seen from fig. 1 that the brightness adjustment curves after fitting are similar to the gamma2.2 curves of 256 gray scales of the display, rise slowly at low brightness, rise quickly at high brightness, and accord with the visual perception characteristics of human eyes. Meanwhile, the transition effect can be further optimized by increasing the adjusting frequency of low brightness and reducing the adjusting frequency of high brightness.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.