Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.
Example one
Fig. 2 is a flowchart illustrating a light valve driving control method according to an exemplary embodiment, which is applied to a projection apparatus integrated with a light source and a light valve composed of a plurality of digital micro-mirror plates, as shown in fig. 2, the method including:
step S110, acquiring first gray scale data of a next frame of image and second gray scale data of a plurality of continuous frames of images adjacent to the next frame of image, wherein the plurality of continuous frames of images are displayed before the next frame of image.
According to fig. 1 and the description in the background art, in the working process of the projection apparatus, when the digital micromirror plate rotates to the on state, the light beam output by the light source enters the lens after being reflected by the digital micromirror plate, so that bright-state pixel points are presented on the screen; when the digital micro-reflector plate rotates to the off state, light beams output by the light source do not enter the lens after being reflected by the digital micro-reflector plate, and therefore dark-state pixel points are displayed on the screen.
In the working process of the projection equipment, an image signal of an image is converted into gray scale data of three primary colors of red, green and blue, namely RGB data, and the gray scale data of each primary color is written into a chip of a light valve in sequence, so that when a corresponding primary color light beam output by a light source is transmitted to a digital micro-mirror chip, the digital micro-mirror chip corresponding to each pixel is driven to rotate according to the gray scale data of the primary color corresponding to the image to be displayed, and thus, the gray scale value of each primary color in the image presented in a screen is the gray scale value indicated by the gray scale data of each primary color, and the digital micro-mirror chip is driven to rotate by the gray scale data of each primary color of the image, so that the image with different gray scales and different brightness is presented on the screen. In other words, the gray scale data of each primary color of the image determines the duration of the on-state and the off-state of the digital micromirror plate corresponding to each pixel during the display process of each frame of image.
The first gradation data indicates a gradation of a next frame image, and similarly, the second gradation data indicates a gradation of consecutive frames of images adjacent to the next frame image.
The continuous frames of images adjacent to the next frame of image are continuous frames of images including the previous frame of image, wherein the previous frame of image is displayed before the next frame of image according to the display sequence of each frame of image, and the images adjacent to the next frame of image. The consecutive frames of images adjacent to the next frame of image may be the previous frame of image, or may be consecutive frames of images including the previous frame of image, and are not particularly limited herein.
The first gray scale data and the second gray scale data may be obtained by performing corresponding conversion on an image signal input to the projection device, or may be directly obtained from gray scale data stored in a chip of the light valve.
In step S130, a gray scale change coefficient is determined according to the first gray scale data and the second gray scale data.
Step S150, judge whether the gray scale change coefficient is in the set coefficient range.
Step S170, if yes, the digital micro-mirror plate is subjected to anti-fatigue rotation in a specified time period in the process of displaying the next frame image, and the anti-fatigue rotation is to turn off the light source in the specified time period and control the digital micro-mirror plate to perform rotation switching for a preset number of times between an on state and an off state.
The gradation change coefficient indicates a degree of change in gradation of the next frame image with respect to gradations of consecutive frames adjacent to the next frame image. In an embodiment, the gray scale change coefficient may be a gray scale change amount and a gray scale change rate of a gray scale of the next frame image relative to gray scales of consecutive frames of images adjacent to the next frame image, a gray scale variance/gray scale mean variance calculated according to the gray scale of the next frame image and the gray scales of consecutive frames of images adjacent to the next frame image, and the like, and is not limited herein.
Since the first gradation data indicates the gradation of the next frame image, similarly, the second gradation data indicates the gradations of consecutive frames of images adjacent to the next frame image. Thus, the gray scale change coefficient can be determined by the first gray scale data and the second gray scale data.
In the case of displaying an image, if the gray scale of the next frame image has a small change from the gray scale of the adjacent displayed image, it means that if the digital micromirror is driven only in accordance with the image signal, the digital micromirror is easily fatigued because the digital micromirror is maintained in the same state (for example, in an on state or an off state) for a long time during the display of the next frame image and the displayed image, and therefore, the digital micromirror needs to be rotated in an anti-fatigue manner during the display of the next frame image to relieve the fatigued state of the digital micromirror.
Judging whether the anti-fatigue rotation is required in the display process of the next frame image according to the set coefficient range, namely if the calculated gray scale change coefficient is positioned in the set coefficient range, indicating that the anti-fatigue rotation is required to be carried out on the digital micro-reflector plate in the display process of the next frame image; if the calculated gray scale change coefficient is out of the set coefficient range, the digital micro-mirror plate does not need to be subjected to anti-fatigue rotation in the display process of the next frame image.
In order to perform anti-fatigue rotation of the digital micro-mirror plate, an anti-fatigue rotation control signal, such as an inversion control signal mentioned below, is correspondingly configured, and the configured anti-fatigue rotation control signal controls the digital micro-mirror plate to perform rotation switching for a preset number of times between an on state and an off state within a specified time period in the display process of the next frame image; and in the display process of the next frame image except for the appointed time period, the digital micro-reflector plate is driven to rotate by the gray scale data of the next frame image.
For a screen displaying an image, as long as an input image signal is continuous, the image displayed on the screen is also continuous, so that a current display image exists on the screen in the display process of the next frame image, and in order to avoid the influence of the anti-fatigue rotation of the digital micro-mirror sheet on the current display image, it is necessary to ensure that the light source does not emit light, so that the light source is ensured to be turned off in a specified time period during which the anti-fatigue rotation is performed.
And determining a gray scale change coefficient according to the first gray scale data of the next frame of image and the second gray scale data of a plurality of continuous frames of images adjacent to the next frame of image, so that the digital micro-reflector plate is subjected to anti-fatigue rotation in the display process of the next frame of image according to the gray scale change coefficient, and the fatigue state of the digital micro-reflector plate can be relieved.
Example two
In one embodiment, as shown in fig. 3, step S130 includes:
step S131, calculating a first gray scale parameter according to the first gray scale data, wherein the first gray scale parameter indicates the gray scale of the next frame image. And
step S132, calculating a second gray scale parameter corresponding to each frame of image in the continuous frames of images according to the second gray scale data, wherein the second gray scale parameter indicates the gray scale of the corresponding frame of image.
Step S133, calculating a gray scale variation coefficient according to the first gray scale parameter and the plurality of second gray scale parameters.
The first gray scale data includes gray scale values of pixels in the next frame of image, and in order to facilitate calculation of the gray scale change coefficient, a first gray scale parameter indicating the gray scale of the next frame of image needs to be calculated according to the first gray scale data.
Similarly, the second gray scale data includes gray scale values of pixels in each of the plurality of frames of images.
In a specific embodiment, the first gray scale parameter and the second gray scale parameter are obtained by averaging gray scale values of each pixel in the corresponding image. The first gray scale parameter is an average gray scale value calculated according to the gray scale value of each pixel in the next frame of image, and correspondingly, the average gray scale value of each displayed image in the plurality of frames of images is calculated according to the gray scale value of each pixel in each displayed image in the plurality of frames of images, so that the second gray scale parameter of each displayed image in the plurality of frames of images is obtained.
EXAMPLE III
In one embodiment, as shown in fig. 4, step S131 includes:
in step S231, the gray scale value of the primary color in each pixel in the next frame of image is obtained from the first gray scale data according to the set primary color.
Step S232, averaging the gray scale values of the primary colors in each pixel in the next frame of image to obtain a first gray scale parameter.
In this embodiment, as shown in fig. 5, step S132 includes:
in step S331, the gray scale value of the primary color in each pixel in each frame of image is obtained from the second gray scale data.
Step S332, respectively averaging the gray scale values of the primary colors in each pixel in each frame of image, to obtain a plurality of second gray scale parameters.
Since the gray scale data of the image comprises the gray scale value of each primary color in each pixel, in order to improve the calculation efficiency, one primary color can be selected as the set primary color, so that the first gray scale parameter and the second gray scale parameter are calculated according to the set primary color, and the calculation efficiency of the first gray scale parameter and the second gray scale parameter is improved. The primary color set therein may be red, green or blue, and is not particularly limited herein.
The primary color set is illustrated as blue:
if the next frame of image includes n pixels, the gray scale data corresponding to the image includes the gray scale values of the three primary colors at each pixel, (R)1,G1,B1),(R2,G2,B2),(R3,G3,B3),……(Rn,Gn,Bn),R1I.e. the gray level value of red at the pixel indicated by reference numeral 1, and, similarly, G1I.e. the gray level value of green at the pixel indicated by reference numeral 1, B1I.e. as indicated at 1Showing the gray scale value of blue at the pixel.
The previous frame of image is taken as a plurality of frame images adjacent to the next frame of image, and the gray-scale values of three primary colors at n pixels in the previous frame of image are as follows: (R)k1,Gk1,Bk1),(Rk2,Gk2,Bk2),(Rk3,Gk3,Bk3),……(Rkn,Gkn,Bkn)。
The first gray-scale parameter P ═ (B)1+B2+B3+…+Bn)/n
Second gray scale parameter Q ═ Bk1+Bk2+Bk3+…+Bkn)/n
Of course, in other embodiments, if the frame images adjacent to the next frame image include a plurality of images including the previous frame image, when the second gray scale parameter is calculated, the gray scale values of the primary colors set in each frame image in each pixel are respectively averaged, so as to obtain the second gray scale parameter corresponding to the image.
Example four
In one embodiment, as shown in fig. 6, step S133 includes:
step S133A, averaging the plurality of second gray scale parameters to obtain an average gray scale parameter.
In step S133B, the variation value of the gray scale parameter is calculated according to the first gray scale parameter and the average gray scale parameter.
Step S133C, calculating a gray scale change coefficient according to the change value of the gray scale parameter and the average gray scale parameter.
In this embodiment, the variation value of the gray scale parameter is divided by the average gray scale parameter to obtain the gray scale variation rate, and the gray scale variation rate is used as the gray scale variation coefficient. That is, for the next frame image whose gray scale value changes rapidly from the displayed image, it is necessary to perform the fatigue resistant rotation of the digital micromirror plate during the display of the next frame image.
EXAMPLE five
In this embodiment, the step S170 includes:
in step S171, in an output period in which the light source outputs the designated primary color light beam for displaying the next frame image, the light source is controlled to be turned off according to the designated period, and the designated period is arranged in the output period of the designated primary color light beam.
And step 172, in the appointed time period of turning off the light source, driving the digital micro-mirror sheet on the light valve to perform rotation switching for preset times between an on state and an off state.
Step S173, when the end time of the rotation switching indicated by the designated time period is reached, the digital micromirror for rotation switching is controlled to return to the state of the digital micromirror itself at the time of the rotation switching start, and the light source is controlled to be turned on.
In the projection equipment, during the projection display of each frame image, the light source realizes the time sequence output of three primary color light beams at least once during the display of the frame image. The light source can realize the time-sequential output of the primary color light beams (including red light beams, blue light beams and green light beams) by configuring a color wheel in the light source, such as a color filter wheel and a fluorescent wheel, or a combination of the fluorescent wheel and the color filter wheel, and light emitted by one light source passes through the rotating color wheel, so that the red light beams, the green light beams and the blue light beams which are output in time-sequential manner are obtained; in another embodiment, in order to realize the time-sequential output of the three primary color light beams, a plurality of primary color light sources may be further configured in the light source, for example, a red light source, a blue light source and a green light source are respectively configured, so that the three primary color light beams are output by the plurality of primary color light sources in time-sequential manner; in other embodiments, a plurality of light sources and a plurality of color wheels may be combined to perform the time-sequential output of three primary color light beams, such as a red light source, a filter color wheel, and a fluorescent wheel. The manner of outputting the three primary color light beams by the light source in a time sequence is not limited.
The specified primary light beam output by the light source may be a red light beam, or a blue light beam, or a green light beam. The output time interval of the primary color light beam is appointed, namely the corresponding time interval of the primary color light beam is output according to the light beam output time sequence of the light source.
In the case of using the color wheel to perform the time-sequential output of the primary color light beam, a boundary line for outputting two adjacent color light beams exists on the color wheel, and since a light spot formed by transmitting the light emitted by the light source onto the color wheel has a certain size, in a region near the boundary line where the color wheel rotates to output two adjacent color light beams, the light beam actually output by the light source is a mixed color light beam, for example, the blue light beam and the red light beam are mixed, and a period during which the color wheel rotates to output the mixed color light beam by the light source when the light source is turned on is referred to as a spoke region period. For example, as shown in fig. 11, when the color filter wheel rotates to the red light transmission region, the red light in the light emitted by the light source transmits through the color filter wheel, so that the light source outputs a red light beam; when the filter color wheel rotates to the blue light transmission area, the blue light in the light emitted by the light source transmits through the filter color wheel, so that the light source outputs a blue light beam. When the color wheel rotates to the boundary between the red transmission area and the blue transmission area or the vicinity of the boundary, the light emitted by the light source forms a light spot with a certain size on the color wheel, so that the light actually output by the light source is a mixed color light beam, i.e., a mixture of the red light beam and the blue light beam.
In the prior art, in order to reduce the influence of the mixed light beams output by the light source in the spoke region time period on the projection display effect, a processing method is to turn off the light source in the spoke region time period, so as to ensure that the light beams output by the light source are all time-sequential light beams with single primary color; in the non-spoke period, the driving control of the light valve can also be performed according to the method of the embodiment.
In another processing method, the light source is still turned on in the spoke region, and the mixed color light beam transmitted through the boundary or the vicinity of the boundary is converted into a single primary color light beam by wavelength conversion or a specific wavelength conversion algorithm, for example, the mixed color light beam transmitted through the blue light transmission region in the spoke region period is converted into a blue light beam, and the mixed color light beam transmitted through the red light transmission region in the spoke region period is converted into a red light beam, so that the spoke region period is divided into periods for outputting two primary color light beams. In the display period in which one time-sequential output period of the light source corresponds to one frame of image, the light beam output by the light source at each moment is still the primary color light beam, that is, the output period in which the light source outputs the specified primary color light beam includes a period in which the primary color light beam is not output by the processing light source and a period in which the primary color light beam is output by the special processing light source in the spoke region. Thus, in this case, the specified period of time may be configured to be within any one of the periods of time of the output of the specified primary color light beam.
In the projection display process, the light source is controlled to be turned off in a specified time period in the output period of the specified primary color light beam output by the light source, and the digital micro-reflector plate on the light valve is driven to perform rotation switching for a preset number of times between an on state and an off state during the turning-off period of the light source, so that the mechanical fatigue state of the digital micro-reflector plate is relieved. Moreover, since the specified time period is configured in the output time period of a certain primary color light beam in the display process of one frame of image, the time for turning off the light source is short, and human eyes cannot perceive the turning off of the light source, even if the light source is turned off in the specified time period and the anti-fatigue rotation of the digital micro-reflector is carried out, the displayed image, namely the image displayed when the light source is turned off can still be normally displayed, and the influence on the image displayed by projection is only that the brightness of the displayed image is reduced, but the change of the image brightness is not large because the time period of the specified time period is short.
In the present embodiment, the light source is turned off only during the display of one frame of image for which the anti-fatigue rotation control is required, instead of performing the anti-fatigue rotation of the digital micromirror plate during the display of each frame of image, so that it is not necessary to turn off the light source during the display of each frame of image.
Fig. 10 is a schematic diagram illustrating a configuration of a designated time period according to an exemplary embodiment, and it should be noted that the diagram is only illustrated by taking an output time period of outputting a blue light beam as an example, and should not be considered as limiting the scope of the present disclosure. As shown in fig. 10, the light source outputs a blue light beam (B) for a period T1, outputs a red light beam (R) for a period T2, and configures a prescribed period T1 for a period T1 according to the timing of the light source outputting the blue light beam, so that, in one period of the light source outputting the primary light beam, the light source is turned off for a prescribed period T1, the light source is turned on for a period T2, and the rotational switching of the digital micromirror plate between the on state and the off state is performed for a prescribed period T1.
Of course, fig. 10 only shows that the turning off of the light source is performed only once during a period in which one light source outputs the primary light beam, which is merely an illustrative example and should not be considered as limiting the scope of the present disclosure. In other embodiments, the turning off of the light source may be performed multiple times in one period in which one light source outputs the primary light beam, and is not limited herein.
EXAMPLE six
In one embodiment, the primary color light beam is designated as a blue light beam. The sensitivity of human eyes to blue is minimum and the contribution of blue to the brightness of the displayed image is minimum relative to red and green, so that the specified time period is configured in the output time period of the light source outputting the blue light beam, even if the light source is turned off in the specified time period, the brightness of the projected displayed image is not greatly changed and can not be distinguished by human eyes, and the influence of the turning-off of the light source on the brightness of the projected displayed image is reduced.
EXAMPLE seven
The duration of the designated time period is 1% -4.5% of the period of the light source outputting the primary color light beam.
In order to perform projection display of an image, the light source performs at least one time of time-sequential output of each primary color light beam in a display period of a frame of image, wherein the time for the light source to complete one time of time-sequential output of each primary color light beam is the period for the light source to output the primary color light beams. During the display of the image, the light source can perform one, two, or even more time-sequential outputs of the various primary color light beams within the display period of one frame image. In each period of outputting the primary light beam by the light source, a specified time period can be configured in the output period of the period of outputting the primary light beam by the light source correspondingly according to the selected primary light beam, for example, the blue light beam.
Taking the display duration of 8.33ms of one frame image as an example, if the light source performs time-sequential output of each primary color light beam once in the one frame image display period, that is, the light source outputs the primary color light beam period of 8.33ms, the duration of the specified time period calculated by, for example, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.7%, 3.2%, 4%, 4.5% and the like of the light source output primary color light beam period may be set, and the specified time period may be further configured. If the light source performs two time-sequential outputs of the primary color light beams in the one-frame image display period, that is, the period of the primary color light beams output by the light source is 4.165ms, the durations of the specified time periods can be correspondingly calculated in percentage, for example, the durations of the rotation switching periods are respectively calculated as 1%, 1.54%, 1.90%, 2.35%, 2.5%, 3.21%, 3.6%, 4.2%, and 4.5%: 41.65us, 64us, 79.14us, 97.88us, 104.13us, 133.70us, 149.94us, 174.93us and 187.43 us.
Therefore, the light source is turned off only in the appointed time period, the digital micro-reflector plate is rotated and switched for preset times between the on state and the off state, and the set rotation switching time period is short, so that the influence on the brightness of the displayed image is small, the fatigue state of the digital micro-reflector plate is known, and the display effect of the normally displayed image can be ensured.
Example eight
In the embodiment, the step S170 includes that the digital micromirror reflects the primary color light beams outputted by the light source in time sequence to perform projection display of the image, the light source is turned off in the spoke region period corresponding to the light source outputting two adjacent primary color light beams to prevent the light source from outputting mixed primary color light beams, and the specified time period is configured in the spoke region period in the display process of the next frame of image:
step S271, driving the digital micromirror plate on the light valve to perform a predetermined number of rotation switching between the on state and the off state within a predetermined time period when the light source is turned off.
Step S272, when the end time of the rotation switching indicated by the designated time period is reached, the digital micromirror for rotation switching is controlled to return to the state of the digital micromirror itself when the rotation switching is started.
The light valve driving control method of the present embodiment is suitable for the above-mentioned spoke region period of the light source, and the light source is turned off during this period. It should be noted that, in the display period of one frame image, the number of spoke region periods of the light source is different according to the number and the type of the color wheel used (for example, the color filter wheel and the fluorescent wheel), but in the embodiment of the present disclosure, the driving control of the light valve is performed in one spoke region period in the display period of one frame image, or in a plurality of spoke region periods according to the method of the present embodiment, and is not particularly limited herein.
In this embodiment, the specified time period is configured in the spoke region time period, and since the light source is turned off in the spoke region time period, a time period with a certain duration may be configured in the spoke region time period as the specified time period, so that the digital micromirror plate is rotationally switched between the on state and the off state for a preset number of times in the specified time period.
Example nine
As shown in fig. 8, in step S172, the digital micromirror plate on the light valve is driven to perform the rotational switching for the preset number of times between the on state and the off state in the specified time period when the light source is turned off, or step S271 includes:
step S410 is to obtain the inversion control signal configured for each digital micromirror plate, where the inversion control signal indicates the preset number of times of rotation switching of the digital micromirror plate between the on state and the off state when the rotation switching end time is reached.
Step S420, in a designated time period, the digital micromirror plate corresponding to the inversion control signal is driven to rotate and switch between the on state and the off state according to the preset times.
In the light valve the digital micromirror plates are independent of each other, so that the pivoting switching of the digital micromirror plates may also be independent of each other, i.e. driven by a corresponding inversion control signal to perform the pivoting switching between an on-state and an off-state. Thus, the inversion control signal is correspondingly configured for each digital micromirror plate.
In one embodiment, the inversion control signals configured for each digital micromirror plate are the same, so that the digital micromirror plates can be uniformly inverted repeatedly during the off period of the light source, i.e., at one moment, the driving is uniformly turned to the on state, and at another moment, the driving is uniformly turned to the off state.
In other embodiments, the inversion control signal configured for each digital micromirror plate may also be different, so that each digital micromirror plate can be controlled randomly, and the inversion control signal is not specifically limited herein.
Example ten
This embodiment provides a projection device comprising a light source, a light valve consisting of a number of digital micromirror plates, and a control means, wherein,
the digital micro-reflector plate on the light valve is used for reflecting the primary color light beams output by the light source in a time sequence so as to perform projection display of an image.
Control means for performing drive control of the light valve in accordance with the method in any one of the above embodiments.
The implementation process in the control device is detailed in the implementation process of the corresponding step in the light valve driving control method, and is not described herein again.
It is understood that the control means may be implemented by hardware, software, or a combination of both. When implemented in hardware, these modules may be implemented as one or more hardware modules, such as one or more application specific integrated circuits. When implemented in software, the modules may be implemented as one or more computer programs executing on one or more processors.
It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.