CN116416914A

CN116416914A - Image display method, device and system and nonvolatile storage medium

Info

Publication number: CN116416914A
Application number: CN202111676762.XA
Authority: CN
Inventors: 何国经; 田征; 王伙荣
Original assignee: Xi'an Ti Pt Sr Electronic Technology Co ltd
Current assignee: Xi'an Ti Pt Sr Electronic Technology Co ltd
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2023-07-11

Abstract

The application discloses an image display method, an image display device, an image display system and a nonvolatile storage medium. Wherein the method comprises the following steps: acquiring an initial gray value and a preset gray value interval of each pixel point in an image to be displayed; determining target gray values of all pixel points according to the initial gray values and a preset gray value interval; the current of the light emitting unit in the display screen is adjusted to be a target current corresponding to a target gray value, wherein the target current is used for enabling the display brightness of the display screen to reach the target display brightness when the display screen displays images; and controlling the display screen to display images according to the target gray value and/or the target current. The application solves the technical problem that the display effect is poor when the existing display screen displays the low-gray-scale image.

Description

Image display method, device and system and nonvolatile storage medium

Technical Field

The present invention relates to the field of image display, and in particular, to a method, an apparatus, a system, and a non-volatile storage medium for displaying an image.

Background

Light emitting diodes (Light Emitting Diode, LEDs) are solid state semiconductor devices that are capable of converting electrical energy into visible light to directly convert electricity into light. The heart of the LED is a semiconductor wafer. The wafer is mainly composed of two parts, wherein one part is a P-type semiconductor, the other part is an N-type semiconductor, and the two semiconductors are connected to form a P-N junction. And positive voltage is applied to the two ends, holes in the P region are recombined with electrons in the N region, redundant energy is released by photons, and photons with different wavelengths are released by different materials, so that different colors are formed.

The on-time of the LED is proportional to the brightness thereof, and at this time, a digital signal (gray scale) representing the brightness can be converted into a time signal, thereby completing the conversion from the digital signal to the optical signal. The brightness of an LED depends on the number of times it is lit per unit time, and also on the magnitude of the passing current.

The lighting time of an LED is affected by several factors: firstly, the LED itself has a capacitance, secondly, the pulse width modulation (Pulse Width Modulation, PWM) outputs a high level once, which has a rise time and a fall time, and finally, the human eye perceives the problem.

The parasitic capacitance exists in the LED, and a certain time is required for charging and discharging of the capacitance, but the clock frequency of the general Gclk is relatively high, and the PWM pulse width is too short, so that the LED can not be lightened. Fig. 1 shows a schematic diagram of an LED on condition, as shown in fig. 1, where PWM is present but the LED cannot be lit.

Next, the effect of the rising time of the PWM is shown in fig. 2, which shows a waveform diagram of the actual output of the PWM, and as shown in fig. 2, the rising and falling response time of the PWM also has a certain effect on the LED on. The effect of t1, t2 is more pronounced when displaying low gray data. When the PWM time is rather short, t1, t2 cannot be ignored. The problem that the LED cannot be lighted is likely to occur, or the display effect is poor after the LED is lighted.

Finally, the perception of the human eye, when the brightness is darker, may illuminate the LED but the human eye cannot. The problem of low gray loss is caused, and the main reason for this occurs is that in the case where the displayed image data is low gray data, the PWM output time is too short to be recognized effectively by the human eye.

The refresh frequency (i.e., visual refresh frequency) of an LED display screen is the number of times a display screen is repeatedly displayed by the display screen per second, in Hz. To cope with indoor shooting scenes, the refresh frequency of the display screen is generally greater than 2000Hz. The requirement of photographing is removed, the display screen with high refresh rate slides the displayed picture rapidly, the generated dynamic blurred picture is less, and the picture felt by human eyes is smooth.

The three factors mentioned above may affect the lighting time of the LED, and further affect the display effect of the LED display screen when displaying images, especially when the LED display screen displays low gray-scale images, and the visual refresh frequency of the LED display screen needs to be improved as much as possible, so as to ensure the display effect.

In view of the above problems, no effective solution has been proposed at present.

Disclosure of Invention

The embodiment of the application provides an image display method, an image display device, an image display system and a nonvolatile storage medium, which are used for at least solving the technical problem that the display effect is poor when a low-gray image is displayed on an LED display screen at present.

According to an aspect of an embodiment of the present application, there is provided a display method of an image, including: acquiring an initial gray value and a preset gray value interval of each pixel point in an image to be displayed; determining target gray values of all pixel points according to the initial gray values and a preset gray value interval; the current of the light emitting unit in the display screen is adjusted to be a target current corresponding to a target gray value, wherein the target current is used for enabling the display brightness of the display screen to reach the target display brightness when the display screen displays images; and controlling the display screen to display images according to the target gray value and/or the target current.

Optionally, determining the target gray value of each pixel according to the initial gray value and the preset gray value interval includes: detecting whether the initial gray value is positioned in a preset gray value interval; under the condition that the initial gray value is located in a preset gray value interval, adopting the preset gray value as a target gray value, wherein the preset gray value is larger than or equal to the maximum boundary value of the preset gray value interval; and taking the initial gray value as a target gray value when the initial gray value is not in the preset gray value interval.

Optionally, before adjusting the current of the light emitting unit in the display screen to the target current corresponding to the target gray value, the method further includes: determining the actual display brightness when the light-emitting unit in the display screen displays the target gray value; determining a difference value between the actual display brightness and the target display brightness; determining a compensation current according to the difference value, wherein the compensation current is a current required for adjusting the actual display brightness of a light-emitting unit in the display screen to target display brightness; the compensation current is determined as the target current.

Optionally, controlling the display screen to display an image according to the target gray value includes: determining a target visual refreshing frequency when a light emitting unit in a display screen displays a target gray value, wherein the visual refreshing frequency is the number of times that the light emitting unit in the display screen is lightened in unit time; and controlling the light emitting units in the display screen to display images according to the target visual refreshing frequency.

Optionally, determining the target visual refresh frequency when the light emitting unit in the display screen displays the target gray value includes: determining the lighting time and the extinguishing time when the light-emitting unit in the display screen displays the target gray value; dividing the lighting time length into a preset number of sub-lighting time lengths on average, and dividing the extinguishing time length into a preset number of sub-extinguishing time lengths on average; and determining the target visual refreshing frequency based on the preset number and the basic visual refreshing frequency of the display screen.

Optionally, determining the target visual refresh frequency based on the preset number and the base visual refresh frequency of the display screen includes: and obtaining the target visual refreshing frequency according to the product of the preset quantity and the basic visual refreshing frequency.

Optionally, controlling the display screen to display an image according to the target gray value further includes: determining the gray data bit number of the target gray value; dividing the number of bits of the gray data into a first number of bits representing the number of frames dividing the target gray value into a plurality of subframes and a second number of bits representing the number of bits of the gray value in each subframe; dividing a target gray value into subframes according to the first bit number and the second bit number; the light emitting units corresponding to the subframes are respectively driven by the pulse width modulation signals so as to display gray values in the subframes.

Optionally, the method further comprises: if the on time of the light emitting unit is K pulse width modulation unit time lengths, setting the target gray scale value to be more than or equal to K.

Optionally, the preset gray value interval is obtained by expanding a low gray value interval by a preset multiple, wherein the low gray value interval is a preset gray value interval, the minimum boundary value of the low gray value interval and the preset gray value interval is the same, and the product of the minimum boundary value of the low gray value interval and the preset multiple is the maximum boundary value of the preset gray value interval.

Optionally, the method further comprises: dividing a low gray value interval into at least two sub gray value intervals, wherein the low gray value interval is a preset gray value interval; taking the initial gray value as a target gray value when the initial gray value is not in the low gray value interval; determining a sub-gray value interval in which the initial gray value falls under the condition that the initial gray value is in the low gray value interval; and selecting a gray value larger than the initial gray value from the sub gray value interval in which the initial gray value falls as a target gray value, and adjusting the current of the light emitting unit in the display screen to be a target current corresponding to the target gray value.

According to another aspect of the embodiments of the present application, there is also provided a display device for an image, including: the acquisition module is used for acquiring the initial gray value and the preset gray value interval of each pixel point in the image to be displayed; the determining module is used for determining the target gray value of each pixel point according to the initial gray value and a preset gray value interval; the setting module is used for adjusting the current of the light emitting unit in the display screen to a target current corresponding to a target gray value, wherein the target current is used for enabling the display brightness of the display screen to reach the target display brightness when the display screen displays images; and the control module is used for controlling the display screen to display images according to the target gray value and/or the target current.

According to still another aspect of the embodiments of the present application, there is also provided a nonvolatile storage medium including a stored program, wherein the device in which the nonvolatile storage medium is controlled to execute the above image display method when the program runs.

According to still another aspect of the embodiments of the present application, there is also provided a processor for executing a program stored in a memory, wherein the program executes the above image display method.

In the embodiment of the application, the method comprises the steps of obtaining an initial gray value and a preset gray value interval of each pixel point in an image to be displayed; determining target gray values of all pixel points according to the initial gray values and a preset gray value interval; the current of the light emitting unit in the display screen is adjusted to be a target current corresponding to a target gray value, wherein the target current is used for enabling the display brightness of the display screen to reach the target display brightness when the display screen displays images; according to the mode of controlling the display screen to display the image by the target gray value and/or the target current, a constant gray data interval is arranged at the low gray part of the image, in the constant gray data interval, the gray of the image is kept constant and a larger value, meanwhile, the brightness change among gray levels is realized by utilizing the current data, the aim of improving the low gray display visual refresh rate by adjusting the display gray data and the current is fulfilled, the visual refresh frequency of the LED display screen when the low gray image is displayed is fulfilled, the technical effect of the display effect of the LED display screen when the low gray image is displayed is further improved, and the technical problem that the display effect is poor when the low gray image is displayed by the LED display screen at present is solved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:

FIG. 1 shows a schematic diagram of an LED on-state;

FIG. 2 shows a PWM actual output waveform;

FIG. 3 is a schematic diagram of an LED illuminated by PWM compensation according to an embodiment of the present application;

FIG. 4 is a schematic diagram of an S-PWM algorithm according to an embodiment of the present application;

FIG. 5 is a schematic diagram of increasing the visual refresh frequency of an LED display screen when displaying low gray scale images in accordance with an embodiment of the present application;

FIG. 6 is a schematic diagram of another S-PWM algorithm according to an embodiment of the present application;

FIG. 7 is a flow chart of a method of displaying an image according to an embodiment of the present application;

FIG. 8 is a flow chart of another method of displaying an image according to an embodiment of the present application;

FIG. 9 is a flow chart of another method of displaying an image according to an embodiment of the present application;

fig. 10 is a block diagram of a structure of a display device of an image according to an embodiment of the present application;

fig. 11 is a block diagram of an image display system according to an embodiment of the present application;

Fig. 12 is a circuit design diagram of an LED display chip according to an embodiment of the present application.

Detailed Description

In order to make the present application solution better understood by those skilled in the art, the following description will be made in detail and with reference to the accompanying drawings in the embodiments of the present application, it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, shall fall within the scope of the present application.

It should be noted that the terms "first," "second," and the like in the description and claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the present application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

First, partial terms or terminology appearing in describing embodiments of the present application are applicable to the following explanation:

in the LED display screen, the gray scale refers to the degree of change in brightness of light emitted from the pixel. The higher the gray level, the richer the color and the more gorgeous the color; otherwise, the display color is single, and the change is simple.

In order to solve the problems in the background art, the existing technical scheme is to use an LED constant current driving chip to correct by compensating PWM, and prolong the lighting time of the LED, namely, lengthen the pulse width time of the PWM. For example, in a display period, PWM occupies 2 Gclk of the display period, and at this time, the compensation mode generally extends the display time of the low-gray-scale image by one or more Gclk, because the gray-scale number is higher, and the influence of several Gclk is small. Fig. 3 is a schematic diagram of an LED that is turned on by PWM compensation according to an embodiment of the present application, as shown in fig. 3, by compensating for an increase in the original PWM by one Gclk period.

Since the brightness that is finally presented by the time each LED display bead is on is actually uncontrollable, the color display of the low gray scale image may not be accurate enough by only increasing the display time of one Gclk. Secondly, if one Gclk is insufficient for compensation, more compensation can change the color of the low-gray-scale image. And the scheme only tries to solve the problem that the LED cannot be turned on, and does not improve the problem that the visual refreshing frequency of the LED display screen is improved.

Another technical scheme is to increase the visual refresh frequency of the LED display screen based on a broken-up pulse width modulation technique (Scrambled Pulse Width Modulation, S-PWM). S-PWM is based on improving the functionality of conventional Pulse Width Modulation (PWM) to break up the time that an image is turned on into several shorter on-times to increase the overall visual refresh frequency. The S-PWM technology disperses the original process mode from on to off in each counting period T into a plurality of average counts, and each dispersed equal part can maintain the duty ratio before dispersion.

FIG. 4 is a schematic diagram of an S-PWM algorithm according to an embodiment of the present application, as shown in FIG. 4, which illustrates 4bit data as an example, when the video data is 1100 _b (b represents binary) in a data period, the time required to light the LED according to the binary bit weight mechanism is 12 _T While being extinguished 3 _T Time, displaying the gray scale thereof with a time duty ratio; and the lighting time is evenly distributed into 3 equal parts in the S-PWM brightness control principle, 5 parts _T Bright 4 _T Fire extinguisher 1 _T (12:3), the total bright time remains 12 _T The time of lighting is unchanged.

The use of S-PWM can increase the visual refresh frequency of the LED display screen when displaying high gray scale images, but when displaying low gray scale images, if the LED is not turned on, the problem of low gray scale loss is more serious, and when the gray scale of the image is lower than the number of scattered subfields (the lighting time 15 in fig. 4 _T Evenly dispersed into 3 equal parts, 5 each _T It can be understood that the number of scattered subfields is 3), and the visual refresh frequency is not improved significantly.

It can be seen that even if the S-PWM algorithm is used, the visual refresh frequency is still low when displaying the low gray image, and considering the influence of the LED on time, the PWM pulse width of 1 time unit corresponding to the gray data 1 may not even turn on the LED, and the problem of low gray loss is further serious after the S-PWM algorithm is used.

Therefore, the display system adopting the S-PWM counting still faces the problems that when the LED display screen displays the low gray level image, the visual refreshing frequency is limited to be improved and the low gray level is lost.

Aiming at the defects of the prior art, the embodiment of the application provides a method for displaying low-gray-scale images by an LED display screen, and the method achieves the technical effect of improving the visual refreshing frequency of the LED display screen when displaying the low-gray-scale images, and further improves the display effect of the LED display screen when displaying the low-gray-scale images.

Fig. 5 is a schematic diagram for improving the visual refresh frequency of an LED display screen when displaying a low-gray-scale image according to an embodiment of the present application, and as shown in fig. 5, the method proposed in the present application supports maintaining constant and large gray-scale data (defined as a "constant gray-scale data area") in a certain low gray-scale range, while realizing brightness variation of gray scales by current data.

As shown in fig. 6, in the display system in which the S-PWM is applied to the display system in which the number of gradation steps of 16 bits is divided into 64 subfields, when the gradation of an image is 64 or less, the PWM is uniformly applied to the image in accordance with the gradation of 64. For a display system with a 60Hz refresh rate, the visual refresh rate can always be 3840Hz with a gray scale of the displayed image less than 64. In other words, the display system has a visual refresh rate of not less than 3840Hz when displaying any gray scale image.

Table 1 is the visual refresh rate when displaying images of respective gray scales using the conventional S-PWM method:

TABLE 1

Table 2 is the visual refresh rate for displaying images of various gray scales using the methods provided herein:

TABLE 2

Inputting gray data	Visual refresh rate (Hz)
		1	3840
2	3840
		3	3840
4	3840
		…	…
63	3840
		64	3840
Greater than 64	3840

The data in tables 1 and 2 above are explained first as follows:

visual refresh frequency = base refresh frequency (60 Hz) the number of parts (i.e. number of sub-fields scattered) that the LED' S on-time is divided equally using S-PWM.

It should be noted that the basic refresh frequency of 60Hz is a common practice in the industry, because in the case that the visual refresh frequency of the display screen is higher than 60Hz for the human eye, a continuous picture is already perceived.

In table 1, see the algorithm of fig. 4, for example, for gray data 1, which is turned on and off only once during a frame time, the visual refresh rate is still 60Hz for a display system with a 60Hz refresh frequency, regardless of whether the S-PWM algorithm is used.

For example, when the S-PWM algorithm is not adopted for gray data 2, the LED lamps are all turned on and off only once in one frame time, and for a display system with 60Hz refreshing frequency, the visual refreshing frequency is 60Hz; when the S-PWM algorithm is adopted, the LED lamps can be switched on and off twice in one frame time, and the visual refresh rate can be increased to 120Hz.

Similarly, for gray data 4, the visual refresh rate can reach 240Hz at maximum when the S-PWM algorithm is used.

In table 2, since the gray scale below 64 is calculated as 64, the visual refresh frequency can be always maintained at 3840Hz for the display system with the refresh frequency of 60Hz, in which case the gray scale is below 64. In other words, the display system has a visual refresh frequency of not less than 3840Hz at any gray level.

The reason why the lighting time of the LED is divided into 64 parts is that the visual refresh frequency can reach 3840Hz when the LED is divided into 64 parts, and the LED display screen already belonging to the middle-high end on the market, that is, the display screen is refreshed 3840 times within 1 second. The high refresh rate can make the display fluency of the picture very good and the definition very high. The refresh frequency is continuously improved, but the cost performance is reduced due to the increase of hardware cost. In the embodiment provided in the application, the method provided in the application is only described in 64 parts, and in the specific embodiment, other values can be set, and the larger the value, the better the display effect theoretically.

The method for displaying the low-gray image by using the LED display screen, which is proposed by the application, is described in detail below through specific embodiments:

according to the embodiments of the present application, there is provided an embodiment of a method of displaying an image, it should be noted that the steps shown in the flowcharts of the drawings may be performed in a computer system such as a set of computer executable instructions, and that although a logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in an order different from that herein.

Fig. 7 is a flowchart of a method for displaying an image according to an embodiment of the present application, as shown in fig. 7, the method includes the steps of:

step S702, obtaining an initial gray value and a preset gray value interval of each pixel in the image to be displayed.

It should be noted that, the initial gray value in step S702 is the gray value mentioned above.

Step S704, determining the target gray value of each pixel point according to the initial gray value and the preset gray value interval.

It should be noted that, the value corresponding to the target gray value is larger than the value corresponding to the initial gray value.

Step S706, the current of the light emitting unit in the display screen is adjusted to a target current corresponding to the target gray value, where the target current is used to make the display brightness of the display screen reach the target display brightness when the display screen displays the image.

The target display luminance is a luminance that is achieved when a light emitting unit in the display screen displays a target gradation value.

After step S704 is performed, it is obvious that the brightness of the display unit in the display screen at this time when the display unit displays the target gray scale is changed, and thus it is necessary to adjust the current data to compensate. The acquisition of the current data may be stored in advance inside the transmission card or the driver IC. Each gray level has a corresponding current data to compensate for brightness.

Step S708, the display screen is controlled to display images according to the target gray values and/or the target currents.

Through the steps, the constant gray data interval is set at the low gray part of the image, the image gray is kept constant and a larger value in the constant gray data interval, meanwhile, the brightness change among gray scales is realized by utilizing the current data, the aim of improving the visual refresh rate of low gray display by adjusting the display gray data and the current is fulfilled, the visual refresh frequency of the LED display screen when the low gray image is displayed is further realized, and the technical effect of the display effect of the LED display screen when the low gray image is displayed is further improved.

According to an alternative embodiment of the present application, step S704 is performed to determine a target gray value of each pixel point according to the initial gray value and the preset gray value interval, including the following steps: detecting whether the initial gray value is positioned in a preset gray value interval; under the condition that the initial gray value is located in a preset gray value interval, adopting the preset gray value as a target gray value, wherein the preset gray value is larger than or equal to the maximum boundary value of the preset gray value interval; and taking the initial gray value as a target gray value when the initial gray value is not in the preset gray value interval.

Fig. 8 is a flowchart of another image display method according to an embodiment of the present application, as shown in fig. 8, the set gray value threshold is 128, that is, the preset gray value interval in the above step S704 is [0,128], and in this step, if the obtained gray value is less than 128, the gray value is processed according to 64×2 or more. All gray values smaller than 128 that are to be acquired are set to be the target gray value greater than or equal to 128.

Describing the above method as an example of a comparative image, the gray scale of the image is 64, and if the image is displayed according to the algorithm shown in fig. 4, the lighting time of the LED is 64 _T The method provided by the application divides the whole counting period of the LED (comprising the LED on time and the LED off time) into 64 equal parts, and takes a 16bit system as an example, the whole counting period of the LED is 2 ¹⁶ -1＝65535 _T About 1024 or so per serving _T Corresponding to handle 64 _T Are evenly dispersed in the 64 parts to be lighted, namely, 1 is lighted in each part _T 。

If the LED on time is equal to about 1 time unit, the LED lamp may not always be lit when the gray data is less than 64, i.e., the gray scale of less than 64 is all lost. Therefore, in order to solve the problem of the LED turn-on delay, the range of the "constant gray data area" can be further increased, the range of the "constant gray data area" can be expanded to [0,128], and when the S-PWM method is adopted, the LEDs in each subfield are turned on for 2 units of time, so that the LED lamp can be better ensured to be turned on normally, and the problem of low gray level loss is improved.

Preferably, setting the gray values smaller than 128 to 128 corresponds to the lighting time 128 of the image with gray values smaller than 128 _T Are evenly dispersed in the 64 parts to be lighted, namely, the lighting in each part is 2 _T (equivalent to LED on time approximately equal to 2 time units) this avoids the problem of low ash data loss due to LED on delay.

It should be noted that 128 may be set to 192 (64×3), and this corresponds to the lighting time 192 of the image having the gray value smaller than 192 _T Are evenly dispersed in the 64 parts to be lightened, namely 3 parts are lightened _T (equivalent to an LED on time of approximately 3 time units).

According to an alternative embodiment of the present application, before step S706 is performed to adjust the current of the light emitting unit in the display screen to the target current corresponding to the target gray value, the actual display brightness when the light emitting unit in the display screen displays the target gray value needs to be determined; determining a difference value between the actual display brightness and the target display brightness; determining a compensation current according to the difference value, wherein the compensation current is a current required for adjusting the actual display brightness of a light-emitting unit in the display screen to target display brightness; the compensation current is determined as the target current.

As an alternative embodiment, the target current data is obtained by making the LED screen display a low gray image, then collecting the brightness of the LED lamp, calculating the difference between the expected brightness and the actual brightness, and changing the current to compensate. When the expected brightness is consistent with the actual brightness, corresponding current data under each low gray level is obtained. The current data is then stored in the transmitting card or the LED driver chip (functions of the transmitting card and the driver chip are described below), and when the low gray data is required to be displayed, the current data control and the S-PWM will cooperate to use the current data corresponding to the current gray value.

According to an alternative embodiment of the present application, step S708 controls the display screen to display an image according to the target gray value by the following method: determining a target visual refreshing frequency when a light emitting unit in a display screen displays a target gray value, wherein the visual refreshing frequency is the number of times that the light emitting unit in the display screen is lightened in unit time; and controlling the light emitting units in the display screen to display images according to the target visual refreshing frequency.

In some alternative embodiments of the present application, determining a target visual refresh frequency at which a light emitting unit in a display screen displays a target gray value comprises the steps of: determining the lighting time and the extinguishing time when the light-emitting unit in the display screen displays the target gray value; dividing the lighting time length into a preset number of sub-lighting time lengths on average, and dividing the extinguishing time length into a preset number of sub-extinguishing time lengths on average; and determining the target visual refreshing frequency based on the preset number and the basic visual refreshing frequency of the display screen.

The method provided in this step has been described above, taking the gray scale of the image to be displayed as 64 as an example, and extending the gray scale 64 to 128, as shown in fig. 6, the visual refresh frequency can reach 3840Hz for a display system implemented with S-PWM scattering as 64 subfields in a 16bit gray scale number.

It should be noted that the preset number may be set to other values, and the setting of 64 is only one typical application scenario.

In an alternative embodiment of the present application, the target visual refresh frequency is determined based on the preset number and the basic visual refresh frequency of the display screen, by the following method: and obtaining the target visual refreshing frequency according to the product of the preset quantity and the basic visual refreshing frequency.

The visual refresh frequency is the product of the base refresh frequency (60 Hz) and the number of copies that the LED' S on-time is divided on average using S-PWM.

According to an alternative embodiment of the present application, performing step S706 to control the display screen to display an image according to the target gray value may also be implemented by the following method: determining the gray data bit number of the target gray value; dividing the number of bits of the gray data into a first number of bits representing the number of frames dividing the target gray value into a plurality of subframes and a second number of bits representing the number of bits of the gray value in each subframe; dividing a target gray value into subframes according to the first bit number and the second bit number; the light emitting units corresponding to the subframes are respectively driven by the pulse width modulation signals so as to display gray values in the subframes.

As an alternative embodiment, for m+n bits of gray data, where M is high and N is low (e.g., gray data bits are 16 bits, where M is 10 bits and N is 6 bits), M represents the number of frames dividing the target gray value into a plurality of subframes, N represents the size of the gray data implemented in each subframe, and the subframe duration is determined, which is related only to the number of bits of the total gray data and the preset number of M, N bits, irrespective of the actual display data.

When in display, the received gray data of the light emitting units are split into subframes according to a certain rule, a plurality of pulse width modulation signals are generated by using a PWM method, the gray data are converted into driving signals of the light emitting devices, and the light emitting devices of one channel are driven in a time-sharing mode.

According to another alternative embodiment of the present application, if the on time of the light emitting unit is K pulse width modulation unit durations, the target gray scale value is set to be greater than or equal to K.

It should be noted that, by setting the target gray value to be equal to or longer than the on time of the light emitting unit in the display screen, it is possible to ensure that the light emitting unit normally displays the target gray value.

According to an optional embodiment of the present application, the preset gray value interval is obtained by expanding a low gray value interval by a preset multiple, where the low gray value interval is a preset gray value interval, a minimum boundary value of the low gray value interval and the preset gray value interval is the same, and a product of the minimum boundary value of the low gray value interval and the preset multiple is a maximum boundary value of the preset gray value interval.

Note that, the low gray value interval is [0,64], the preset multiple is 2 times, and other multiples may be set, and since the low gray value interval is the default value [0,64], if the preset multiple is set to other values, the preset gray interval is changed accordingly.

The low gradation value interval may be set to another value interval.

In another optional embodiment of the present application, the method further includes: dividing a low gray value interval into at least two sub gray value intervals, wherein the low gray value interval is a preset gray value interval; taking the initial gray value as a target gray value when the initial gray value is not in the low gray value interval; determining a sub-gray value interval in which the initial gray value falls under the condition that the initial gray value is in the low gray value interval; and selecting a gray value larger than the initial gray value from the sub gray value interval in which the initial gray value falls as a target gray value, and adjusting the current of the light emitting unit in the display screen to be a target current corresponding to the target gray value.

Fig. 9 is a flowchart of another image display method according to an embodiment of the present application, in which, as shown in fig. 9, a low gray value section is simply divided (a judgment gray value of 32 or less is set to 32 or more and 64 or less is set to 64) while compensation is performed using a current. Because the adjustable range of the current data is limited, the gray value interval is divided into two (or more) sub-gray value intervals, and the same current data can be used for different gray scales (the original gray scale 1 and the gray scale 33 are assumed), so that the utilization rate of the current of the same gear can be improved.

In the current LED display system adopting the S-PWM technology, when the gray scale is smaller than the number of scattered subfields, the refresh frequency of the display screen is improved and the gray scale is positively correlated, so that when the gray scale is very small, the refresh frequency is improved only to a limited extent; on the other hand, the S-PWM algorithm aggravates the problem of low gray-scale loss due to LED turn-on delay. The refresh frequency of the LED display screen when displaying the low-gray-scale image is generally 60Hz, and the method provided by the application aims to improve the refresh frequency of the LED display screen when displaying the low-gray-scale image to more than tens of times of the original refresh frequency (particularly, the method is determined according to the number of scattered subfields so as to scatter 64 subfields, and can improve the refresh rate to 3840 Hz). The method provided by the application is characterized in that a constant gray data area is partially arranged in a low gray value interval, gray data is kept constant and a larger value in the gray value interval, and meanwhile brightness change among gray scales is realized by utilizing current data. The display visual refreshing frequency of the LED display screen under the condition of displaying low gray data can be obviously improved, and meanwhile, the problem of low gray loss is solved, so that the display under the condition of displaying low gray images is still good.

Fig. 10 is a block diagram of a display device for images according to an embodiment of the present application, as shown in fig. 10, the device includes:

The acquiring module 100 is configured to acquire an initial gray value and a preset gray value interval of each pixel point in an image to be displayed;

the determining module 102 is configured to determine a target gray value of each pixel point according to the initial gray value and a preset gray value interval;

a setting module 104, configured to adjust a current of a light emitting unit in the display screen to a target current corresponding to a target gray value, where the target current is used to make a display brightness of the display screen reach a target display brightness when the display screen displays an image;

and the control module 106 is used for controlling the display screen to display images according to the target gray value and/or the target current.

It should be noted that, the preferred implementation manner of the embodiment shown in fig. 10 may refer to the related description of the embodiment shown in fig. 7, which is not repeated herein.

Through the device, the constant gray data interval is arranged at the low gray part of the image, the image gray is kept constant and a larger value in the constant gray data interval, and meanwhile, the brightness change among gray scales is realized by utilizing the current data, so that the aim of improving the visual refresh rate of low gray display by adjusting the display gray data and the current is fulfilled, the visual refresh frequency of the LED display screen when the low gray image is displayed is realized, and the technical effect of the display effect of the LED display screen when the low gray image is displayed is further improved.

Fig. 11 is a block diagram of an image display system according to an embodiment of the present application, in which an LED driving chip used in the present application supports current adjustment, as shown in fig. 11, and current data and gray data of an image can be received from an LED display controller through a receiving card.

The LED driving chips can be used in cascade, the LED_LINE is a LINE scanning signal, and the LED_OUT is a channel LED signal. The upper module sends the acquired current data and the gray data of the image to the LED display chip, the LED display chip controls the display brightness of the LED display screen when the low gray image is displayed through the current data, and the visual refreshing brightness of the LED display screen when the low gray image is displayed is improved through the gray data of the image.

Fig. 12 is a circuit design diagram of an LED display chip according to an embodiment of the present application, as shown in fig. 12, in which LE is a synchronization signal, GCLK is a gray scale clock, and may be generated from the outside, or may be generated from a DCLK data clock using a phase locked loop PLL. The LED display chip comprises a data shift register, an image data latch register, a gray level judging module, an S-PWM processing module, a comparator, a current regulating module and the like.

The embodiment of the application also provides a nonvolatile storage medium, which comprises a stored program, wherein the program is used for controlling the equipment where the nonvolatile storage medium is located to execute the display method of the image.

The above-described nonvolatile storage medium is used to store a program that performs the following functions: acquiring an initial gray value and a preset gray value interval of each pixel point in an image to be displayed; determining target gray values of all pixel points according to the initial gray values and a preset gray value interval; the current of the light emitting unit in the display screen is adjusted to be a target current corresponding to a target gray value, wherein the target current is used for enabling the display brightness of the display screen to reach the target display brightness when the display screen displays images; and controlling the display screen to display images according to the target gray value and/or the target current.

The embodiment of the application also provides a processor, which is used for running the program stored in the memory, wherein the program runs to execute the image display method.

The processor is configured to execute a program that performs the following functions: acquiring an initial gray value and a preset gray value interval of each pixel point in an image to be displayed; determining target gray values of all pixel points according to the initial gray values and a preset gray value interval; the current of the light emitting unit in the display screen is adjusted to be a target current corresponding to a target gray value, wherein the target current is used for enabling the display brightness of the display screen to reach the target display brightness when the display screen displays images; and controlling the display screen to display images according to the target gray value and/or the target current.

The foregoing embodiment numbers of the present application are merely for describing, and do not represent advantages or disadvantages of the embodiments.

In the foregoing embodiments of the present application, the descriptions of the embodiments are emphasized, and for a portion of this disclosure that is not described in detail in this embodiment, reference is made to the related descriptions of other embodiments.

In the several embodiments provided in the present application, it should be understood that the disclosed technology content may be implemented in other manners. The above-described embodiments of the apparatus are merely exemplary, and the division of the units, for example, may be a logic function division, and may be implemented in another manner, for example, a plurality of units or components may be combined or may be integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be through some interfaces, units or modules, or may be in electrical or other forms.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be essentially or a part contributing to the related art or all or part of the technical solution may be embodied in the form of a software product stored in a storage medium, including several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a removable hard disk, a magnetic disk, or an optical disk, or other various media capable of storing program codes.

The foregoing is merely a preferred embodiment of the present application and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present application and are intended to be comprehended within the scope of the present application.

Claims

1. A method of displaying an image, comprising:

acquiring an initial gray value and a preset gray value interval of each pixel point in an image to be displayed;

determining target gray values of the pixel points according to the initial gray values and the preset gray value interval;

adjusting the current of a light emitting unit in a display screen to be a target current corresponding to the target gray value, wherein the target current is used for enabling the display brightness of the display screen when the image is displayed to reach target display brightness;

and controlling the display screen to display the image according to the target gray value and/or the target current.

2. The method of claim 1, wherein determining the target gray value for each pixel from the initial gray value and the preset gray value interval comprises:

detecting whether the initial gray value is positioned in the preset gray value interval;

Adopting a preset gray value as the target gray value when the initial gray value is in the preset gray value interval, wherein the preset gray value is larger than or equal to the maximum boundary value of the preset gray value interval;

and taking the initial gray value as the target gray value when the initial gray value is not in the preset gray value interval.

3. The method of claim 1, wherein prior to adjusting the present current of the light emitting cells in the display screen to a target current corresponding to the target gray value, the method further comprises:

determining the actual display brightness when the light-emitting units in the display screen display the target gray values;

determining a difference between the actual display brightness and the target display brightness;

determining a compensation current according to the difference value, wherein the compensation current is a current required for adjusting the light-emitting units in the display screen from the actual display brightness to the target display brightness;

the compensation current is determined as the target current.

4. A method according to any one of claims 1 to 3, wherein controlling the display screen to display the image in accordance with the target gray value comprises:

Determining a target visual refreshing frequency when a light emitting unit in the display screen displays the target gray value, wherein the visual refreshing frequency is the number of times that the light emitting unit in the display screen is lightened in unit time;

and controlling a light emitting unit in the display screen to display the image according to the target visual refreshing frequency.

5. The method of claim 4, wherein determining a target visual refresh frequency at which a lighting unit in the display screen displays the target gray value comprises:

determining the lighting time length and the extinguishing time length when the light-emitting units in the display screen display the target gray values;

dividing the lighting time length into a preset number of sub-lighting time lengths on average, and dividing the extinguishing time length into the preset number of sub-extinguishing time lengths on average;

and determining the target visual refreshing frequency based on the preset quantity and the basic visual refreshing frequency of the display screen.

6. The method of claim 5, wherein determining the target visual refresh frequency based on the preset number and a base visual refresh frequency of the display screen comprises:

and obtaining the target visual refreshing frequency according to the product of the preset quantity and the basic visual refreshing frequency.

7. A method according to any one of claims 1 to 3, wherein controlling the display screen to display the image in accordance with the target gray value further comprises:

determining the gray data bit number of the target gray value;

dividing the number of bits of the gray data into a first number of bits representing a number of frames dividing the target gray value into a plurality of subframes and a second number of bits representing a number of bits of the gray value in each subframe;

dividing the target gray value into subframes according to the first bit number and the second bit number;

and respectively driving the light emitting units corresponding to the subframes by using pulse width modulation signals so as to display the gray values in the subframes.

8. The method of claim 7, wherein the method further comprises:

and if the starting time of the light emitting unit is K pulse width modulation unit time lengths, setting the target gray scale value to be more than or equal to K.

9. The method according to claim 1, wherein the preset gray-value interval is obtained by expanding a low gray-value interval by a preset multiple, wherein the low gray-value interval is a preset gray-value interval, the low gray-value interval is identical to a minimum boundary value of the preset gray-value interval, and a product of the minimum boundary value of the low gray-value interval and the preset multiple is a maximum boundary value of the preset gray-value interval.

10. The method according to claim 1, wherein the method further comprises:

dividing a low gray value interval into at least two sub gray value intervals, wherein the low gray value interval is a preset gray value interval;

taking the initial gray value as the target gray value when the initial gray value is not in the low gray value interval;

determining the sub-gray value interval in which the initial gray value falls when the initial gray value is in the low gray value interval;

and selecting a gray value larger than the initial gray value from the sub gray value interval in which the initial gray value falls as the target gray value, and adjusting the current of the light emitting unit in the display screen to be a target current corresponding to the target gray value.

11. An image display device, comprising:

the acquisition module is used for acquiring the initial gray value and the preset gray value interval of each pixel point in the image to be displayed;

the determining module is used for determining target gray values of the pixel points according to the initial gray values and the preset gray value interval;

The setting module is used for adjusting the current of the light emitting unit in the display screen to be a target current corresponding to the target gray value, wherein the target current is used for enabling the display brightness of the display screen when the image is displayed to reach the target display brightness;

and the control module is used for controlling the display screen to display the image according to the target gray value and/or the target current.

12. A non-volatile storage medium, characterized in that the non-volatile storage medium comprises a stored program, wherein the program, when run, controls a device in which the non-volatile storage medium is located to perform the method of displaying an image according to any one of claims 1 to 10.

13. A processor for executing a program stored in a memory, wherein the program is executed to perform the method of displaying an image according to any one of claims 1 to 10.