Projection control method and device, projector and storage medium

Abstract

The invention discloses a projection control method and device, a projector and a storage medium. The method comprises the steps of determining a base point of a target color gamut of a to-be-projected image; determining a conversion coefficient between the color space representation of the plurality of light sources and the color space representation of the base point; determining a first color space representation of the pixel point according to the initial color space representation of the pixel point and the color space representation of the base point; determining an adjustment factor according to the first color space representation of the pixel point; determining a target color space representation of the pixel point according to the adjustment factor and the first color space representation of the pixel point; determining a target light source combination representation according to the adjustment factor and the conversion coefficient; and according to the target color space representation and the target light source combination representation of the pixel points, controlling to project the to-be-projected image. In the application, the target light source combination representation is used for controlling light emitting of the light sources, light emitting waste is reduced, power consumption is reduced, the target color space representation is used for controlling the color of the displayed image, and light transmittance and picture brightness are improved.

Description

Technical Field

[0001] The present application relates to the technical field of projection control, and more specifically, to a projection control method, apparatus, electronic device, and computer-readable storage medium. Background Art

[0002] In a Digital Light Processing (DLP) projector, each light source emits light according to a constant excitation current value. When the projector projects a specific image, the image is displayed in various colors through the digital micromirror device (DMD) of the projector. However, with the existing control method, the light output of the light source is wasted and the power consumption is high.

[0003] Therefore, there is an urgent need for a projection control method that can reduce the waste of light output of the light source and reduce power consumption while ensuring the brightness of the display screen. Summary of the Invention

[0004] The present application provides a projection control method, apparatus, projector, and storage medium to improve the above-mentioned defects.

[0005] In a first aspect, an embodiment of the present application provides a projection control method for a projector including a plurality of light sources. The method includes: determining a base point of a target color gamut corresponding to the image to be projected according to the color coordinates of a target pixel point in the image to be projected; determining a conversion coefficient between the color space representations of the plurality of light sources and the color space representation of the base point of the target color gamut; determining a first color space representation of a pixel point in the image to be projected in the target color gamut according to the initial color space representation of the pixel point in the image to be projected and the color space representation of the base point of the target color gamut; determining an adjustment factor of the image to be projected according to the first color space representation of the pixel point in the image to be projected in the target color gamut; determining a target color space representation of the pixel point in the image to be projected according to the adjustment factor of the image to be projected and the first color space representation of the pixel point in the target color gamut; determining a target light source combination representation of the base point of the target color gamut according to the adjustment factor of the image to be projected and the conversion coefficient; and controlling the projector to project the image to be projected according to the target color space representation of the pixel point in the image to be projected and the target light source combination representation of the base point.

[0006] In a second aspect, an embodiment of the present application further provides a projection control apparatus for a projector including a plurality of light sources. The apparatus includes:

[0007] A first determination module for determining a base point of a target color gamut corresponding to the image to be projected according to the color coordinates of a target pixel point in the image to be projected;

[0008] A second determination module for determining a conversion coefficient between the color space representations of the plurality of light sources and the color space representation of the base point of the target color gamut;

[0009] A third determination module, configured to determine a first color space representation of a pixel of the image to be projected in the target color gamut according to an initial color space representation of the pixel of the image to be projected and a color space representation of a base point of the target color gamut;

[0010] A fourth determination module, configured to determine an adjustment factor of the image to be projected according to the first color space representation of the pixel of the image to be projected in the target color gamut;

[0011] A fifth determination module, configured to determine a target color space representation of a pixel of the image to be projected according to the adjustment factor of the image to be projected and the first color space representation of the pixel in the target color gamut;

[0012] A sixth determination module, configured to determine a target light source combination representation of a base point of the target color gamut according to the adjustment factor of the image to be projected and a conversion coefficient;

[0013] A projection module, configured to control a projector to project the image to be projected according to the target color space representation of the pixel of the image to be projected and the target light source combination representation of the base point.

[0014] In a third aspect, an embodiment of the present application further provides a projector, including: one or more processors; a memory; one or more applications, where one or more applications are stored in the memory and configured to be executed by one or more processors, and one or more programs are configured to execute the above method.

[0015] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium, where the computer-readable storage medium stores program code executable by a processor, and when the program code is executed by the processor, the processor executes the above method.

[0016] A projection control method, device, projector, and storage medium provided in the present application. In the present application, a base point of a target color gamut is determined through a pixel of an image to be processed, where the target color gamut is a color gamut suitable for the current image to be projected. After obtaining the base point of the target color gamut, a conversion coefficient between a color space representation of a plurality of light sources and a color space representation of the base point of the target color gamut is determined. An adjustment factor is used to further amplify the first color space representation of a pixel in the target color gamut to obtain a target color space representation of the pixel in the image to be projected. The spatial light modulator is controlled through the target color space representation of the pixel, improving the transmittance of the spatial light modulator, reducing the power consumption of the projector, enhancing the light utilization rate, and at the same time enhancing the brightness of the projection image and improving the color restoration degree of the image to be projected. A target light source combination representation of the base point determined according to the adjustment factor and the conversion coefficient is used to control the excitation current of the light source, reducing the waste of light output and further reducing the power consumption of the projector.

[0017] Other features and advantages of the embodiments of the present application will be described in the subsequent specification, and in part will be obvious from the specification, or will be understood by implementing the embodiments of the present application. The objectives and other advantages of the embodiments of the present application can be achieved and obtained by the structures specifically pointed out in the written specification, claims, and drawings. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 Shows a flowchart of a projection control method according to an embodiment of the present application.

[0020] Figure 2 Shows a schematic diagram of current drive in the embodiments of the present application.

[0021] Figure 3 Shows a flowchart of a projection control method according to another embodiment of the present application.

[0022] Figure 4 Shows a flowchart of a projection control method according to still another embodiment of the present application.

[0023] Figure 5 Shows a block diagram of the structure of a projection control device according to an embodiment of the present application.

[0024] Figure 6 Shows a block diagram of the structure of another projection control device according to an embodiment of the present application.

[0025] Figure 7 Shows a schematic diagram of a projector provided in the embodiments of the present application.

[0026] Figure 8 Shows a schematic diagram of a computer-readable storage medium provided in the embodiments of the present application. Detailed Embodiments

[0027] To enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Usually, the components of the embodiments of this application described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but only represents the selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative efforts belong to the scope of protection of this application.

[0028] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0029] Please refer to Figure 1 , Figure 1 which shows a flowchart of a projection control method proposed in an embodiment of this application for a projector including multiple light sources. The method includes:

[0030] S101. Determine the base points of the target color gamut corresponding to the image to be projected according to the color coordinates of the target pixel points in the image to be projected.

[0031] The image to be projected is a color image, which can be an image or a video frame. There can be multiple target pixel points, and the target pixel points can be any pixel point in the image to be projected; the target pixel points can be some pixel points obtained from the image to be projected. For example, the target pixel points can be pixel points with a brightness value higher than a preset brightness value or a pixel value higher than a preset pixel value, etc.

[0032] The color coordinate refers to the position of a color in the color space. The color coordinate of the target pixel point here refers to the position of the color corresponding to the target pixel point in the color space. The color coordinate of a color does not change with the color gamut it belongs to, that is, the color coordinate of the target pixel point is fixed.

[0033] A color gamut is a method of encoding a color, and also refers to the sum of colors that a technical system can produce. A color gamut describes a set of colors, that is, the color coverage range. The target color gamut is the set of colors corresponding to the image to be projected. The target color gamut can be the same as the standard color gamut or a part of the standard color gamut. The standard color gamut can be the standard Red Green Blue (sRGB) color gamut, the Adobe RGB color gamut, etc. The base point of the target color gamut refers to the color point selected as a reference or benchmark in the target color gamut. All points in the target color gamut can be represented by the base point of the target color gamut. Generally, the base point of the target color gamut is the vertex of the target color gamut.

[0034] S102. Determine the conversion coefficient between the color space representation of multiple light sources and the color space representation of the base point of the target color gamut.

[0035] The color space representation of a light source means representing the light source through the color space, and the color space representation of the base point of the target color gamut means representing the base point of the target color gamut through the color space.

[0036] The color space can be XYZ, RGB, Yuv, etc. Here, the light source and the base point of the target color gamut are represented through the XYZ color space, that is, to determine the conversion coefficient between the tristimulus values of multiple light sources and the tristimulus values of the base point of the target color gamut. The tristimulus values are the representations of the stimulation levels of the three primary colors that cause the human retina to feel a certain color, and the tristimulus values are represented by X (the stimulation amount of the red primary color), Y (the stimulation amount of the green primary color), and Z (the stimulation amount of the blue primary color).

[0037] The number of base points of the target color gamut is related to the number of color segments corresponding to the display system of the projector. If the color segments corresponding to the projector are three-color segments, then the base points of the target color gamut are also three, and the shape of the target color gamut is a triangle with three base points as vertices; if the color segments corresponding to the projector are six-color segments, then the base points of the target color gamut are also six, and the shape of the target color gamut is a hexagon with six base points as vertices.

[0038] In some embodiments, the initial color space representation of the base point can be obtained, and the base point is converted from the initial color space to the color space to obtain the intermediate color space representation of the base point.

[0039] Among them, the initial color space is the xyY color space, the intermediate color space is the XYZ color space, and the color coordinates of the base point of the target color gamut are known, that is, the (x i , y i ) of the base point i is known. Then, by setting the relative luminance Y i of the base point of the target color gamut to 1, the initial color space representation of the base point i can be obtained as [x i y i Y i .

[0040] Given the [x i y i Y i of the known base point i, it is calculated by the calculation formula (1), and the calculation formula (1) is as follows:

[0041]

[0042] The initial color space representation [x i y i Y i of the base point i can be converted into the intermediate color space representation Furthermore, the intermediate color space representations of all the base points in the target color gamut are obtained respectively. The intermediate color space representation of the base point is the relative value obtained when the relative luminance Y i of the base point in the target color gamut is 1.

[0043] In some embodiments, the method for obtaining the color space representations of multiple light sources may include: obtaining the initial color space representations of multiple light sources, and converting the multiple light sources from the initial color space to the color space to obtain the color space representations of the multiple light sources.

[0044] Among them, according to the light source specification, the initial color space representation of the light source j is determined as [x j y j Y j . Through the calculation formula (1), the initial color space representation [x j y j Y j can be converted into the color space representation

[0045] The projector includes multiple light sources. It can be assumed that the number of light sources is n. Then the color space representations of the multiple light sources are

[0046] In some embodiments, the number of light sources of the projector is greater than the number of color segments of the projector; S102 may include: constructing an equation of the conversion coefficient according to the color space representations of the base points in the target color gamut and the color space representations of the multiple light sources; solving the equation by the linear programming method to obtain the conversion coefficient.

[0047] Among them, the equation of the conversion coefficient is shown in Equation (2):

[0048]

[0049] Among them, C iis the conversion coefficient between the color space representation of multiple light sources and the intermediate color space representation of the base point i of the target color gamut. Since there are n light sources, if the number of color segments corresponding to the projector is less than the number of light sources, C i There are infinitely many solutions.

[0050] In some embodiments, the constraint condition of the linear programming method is that the conversion coefficient is between 0 and 1, and the optimization objective of the linear programming method is to maximize the conversion coefficient, that is, to maximize the control parameter of the corresponding light source, so as to improve the brightness of the light output by the light source as much as possible. That is to say, the constraint condition is C i > 0, and the optimization objective is MIN(MAX(C i ))

[0051] Actually, when obtaining the initial color space representation of the base point, let the relative luminance Y of the base point i of the target color gamut i be 1. This 1 is a relative value, that is, each value in the obtained optimal solution matrix is a relative value. Therefore, after obtaining the optimal solution of the equation, each value in the optimal solution matrix needs to be divided by the maximum value to convert it into an absolute value, and the obtained result is the conversion coefficient C i .

[0052] Among them, each base point corresponds to a conversion coefficient, and the number of obtained conversion coefficients is the same as the number of base points of the target color gamut.

[0053] After obtaining multiple conversion coefficients between the intermediate color space representation of multiple light sources and the color space representation of the base points of the target color gamut through the above method, when the color space representations of multiple light sources are known, substituting the conversion coefficients into the calculation formula (2) can obtain the color space representation of the base point corresponding to the conversion coefficient, and the color space representation of the base point is an absolute value.

[0054] S103. Determine the first color space representation of the pixel points of the to-be-projected image in the target color gamut according to the initial color space representation of the pixel points of the to-be-projected image and the color space representation of the base points of the target color gamut.

[0055] The initial color space representation of the pixel point is the color space representation of the pixel point when maintaining the chromaticity coordinates of the pixel point unchanged and Y taking the relative value 1. The chromaticity coordinates of the pixel point are the chromaticity coordinates calculated from the color space representation of the pixel point directly read from the to-be-projected image; the color space representation of the base point of the target color gamut refers to representing the base point of the target color gamut through the color space; the first color space representation of the pixel point in the target color gamut is to represent the pixel point with the base point of the target color gamut.

[0056] In some embodiments, the initial color space representation of a pixel is the representation of the pixel in the XYZ color space, and the Y value is taken as 1; the initial color space representation of pixel i can be expressed as [X i Y i Z i . The first color space representation of the pixel under the target color gamut is the representation of the pixel in the RGB color space. The first color space representation of pixel i under the target color gamut can be expressed as

[0057] S104. Determine the adjustment factor of the image to be projected according to the first color space representation of the pixels of the image to be projected under the target color gamut.

[0058] Among them, the adjustment factor of the image to be projected is the adjustment factor of the global grayscale image to be projected, which is used to adjust the brightness of the overall displayed image.

[0059] In some embodiments, the projector has multiple light-emitting color segments, and the adjustment factor includes the adjustment coefficients corresponding to the respective different light-emitting color segments. If the projector has 3 light-emitting color segments, the adjustment factor includes the adjustment coefficients corresponding to the 3 light-emitting color segments respectively; if the projector has 6 light-emitting color segments, the adjustment factor includes the adjustment coefficients corresponding to the 6 light-emitting color segments respectively.

[0060] In some embodiments, the maximum value of the first color space representations of multiple pixels under the target color gamut can be obtained as the adjustment factor of the image to be projected. Specifically, the maximum values of R, G, and B in the RGB color space of all pixels under the target color gamut can be obtained as the adjustment coefficients of the corresponding color segments, which together constitute the adjustment factor.

[0061] Taking the projector with 3 light-emitting color segments as an example, defining the adjustment factor of the global grayscale image to be projected as (s r , s g , s b ), then:

[0062]

[0063] Among them, s r is the adjustment coefficient of the red light color segment, s g is the adjustment coefficient of the green light color segment, s b is the adjustment coefficient of the blue light color segment. When the adjustment factor of the image to be projected is 0, this adjustment factor can be assigned a value of 1×10 ―16 .

[0064] Since each of R, G, and B corresponds to one light-emitting color segment of the projector display system, when the maximum values of R, G, and B are respectively obtained as the corresponding adjustment coefficients to form an adjustment factor, the projection image of the corresponding light-emitting color segment can be adjusted by the adjustment coefficient corresponding to each light-emitting color segment, with high flexibility and further power consumption reduction.

[0065] S105. Determine the target color space representation of the pixel of the image to be projected according to the adjustment factor of the image to be projected and the first color space representation of the pixel under the target color gamut.

[0066] Among them, the target color space representation of the pixel is the representation of the pixel in the RGB color space.

[0067] The first color space representation of pixel i under the target color gamut is The adjustment factor of the image to be projected is [s r s g s b , and the target color space representation of the pixel is [r i g i b i . The [r i g i b i can be calculated by the calculation formula (3). The calculation formula (3) is as follows:

[0068]

[0069] The first color space representation of the pixel under the target color gamut is further amplified by the adjustment factor to obtain the target color space representation of the pixel under the target color gamut. The spatial light modulator is controlled by the target color space representation of the pixel, which improves the transmittance of the spatial light modulator, reduces power consumption, and improves light utilization.

[0070] S106. Determine the target light source combination representation of the base point of the target color gamut according to the adjustment factor of the image to be projected and the conversion coefficient.

[0071] Among them, the target light source combination representation is the coefficient for adjusting the light source brightness to the light source brightness applicable to the target color gamut, and each base point of the target color gamut corresponds to a target light source combination representation.

[0072] Among them, the adjustment factor of the image to be projected is [s r s g s b , the conversion coefficient corresponding to the base point i of the target color gamut is C i , and the target light source combination representation of the base point i of the target color gamut is It can be calculated by the calculation formula (4). The calculation formula (4) is as follows:

[0073]

[0074] S107. Control the projector to project the image to be projected according to the target color space representation of the pixel points of the image to be projected and the target light source combination representation of the reference point.

[0075] Input the target color space representation of the pixel points into the digital micromirror device (DMD) of the projector, that is, into the spatial light modulator. Input the target light source combination representation of the reference point into the light source of the projector. Given the known light source brightness, generate a look-up table of the correspondence between the target light source combination representation and the current according to the current-light source brightness curve. According to the target light source combination representation of the reference point, look up the look-up table of the correspondence to obtain the input current corresponding to the reference point, and input the current into the power control device to control multiple light sources to emit light and project it onto the DMD. Then, the DMD controls the projection of the image to be projected according to the target color space representation of the pixel points.

[0076] As Figure 2 shown, Figure 2 The figure is a schematic diagram of current drive when the light output color segment of the display system of the projector is 3 color segments and the light source is 6 light sources.

[0077] In this embodiment, the reference point of the target color gamut is determined through the pixel points of the image to be processed, and the target color gamut is the color gamut suitable for the current image to be projected. After obtaining the reference point of the target color gamut, determine the conversion coefficient between the color space representation of multiple light sources and the color space representation of the reference point of the target color gamut. Further amplify the first color space representation of the pixel points in the target color gamut through the adjustment factor to obtain the target color space representation of the pixel points in the image to be projected. Control the spatial light modulator through the target color space representation of the pixel points, improve the transmittance of the spatial light modulator, reduce the power consumption of the projector, improve the light utilization rate, and at the same time improve the brightness of the projection screen, dynamically improve the color gamut coverage range of the projector, improve the color restoration degree of the image to be projected. According to the target light source combination representation of the reference point determined by the adjustment factor and the conversion coefficient, control the excitation current of the light source through the target light source combination representation, reduce the light output waste, and further reduce the power consumption of the projector.

[0078] In some embodiments, as Figure 3 shown, S103 includes:

[0079] S201. Calculate the second color space representation of the pixel points of the image to be projected in the target color gamut according to the initial color space representation of the pixel points of the image to be projected, the color space representation of the reference point of the target color gamut, and the duty ratio of each light output color segment corresponding to the projector.

[0080] Among them, the duty cycle of the light-emitting color segment refers to the time ratio of a light-emitting color segment in a cycle. Each pixel can be composed of multiple light-emitting color segments, and each light-emitting color segment represents the color presented by the pixel in that cycle.

[0081] Assume that the multiple light-emitting color segments corresponding to the projector are three light-emitting color segments. Then the duty cycle of each light-emitting color segment is d = (d1, d2, d3), and the initial color space of pixel i is represented as [X i Y i Z i . The color space representations of the three base points of the target color gamut are The second color space representation of pixel i under the target color gamut Can be calculated by formula (5) Formula (5) is as follows:

[0082]

[0083] Since the Y of the pixel i Is a relative value, the calculated Is a relative value.

[0084] S202. Determine the target brightness gain value according to the second color space representation of the pixel of the image to be projected under the target color gamut.

[0085] In some embodiments, S202 may include: determining the scaling factor corresponding to each pixel according to the second color space representation of the pixel of the image to be projected under the target color gamut; determining the target scaling factor according to the scaling factor corresponding to the pixel of the image to be projected; determining the brightness gain value corresponding to each pixel according to the target scaling factor and the scaling factor corresponding to each pixel; arranging the brightness gain values corresponding to the pixels of the image to be projected in ascending order to obtain a brightness gain sequence; determining the target brightness gain value from the brightness gain sequence.

[0086] Among them, the scaling factor is used to convert the second color space representation of the pixel into an absolute value. Define the scaling factor as s i , then s i Is expressed as:

[0087]

[0088] Among them, Is the maximum value of the second color space representation of pixel i.

[0089] After obtaining the scaling factor of pixel i, determine the target scaling factor from the scaling factors corresponding to each of the multiple pixels. The target scaling factor can be the maximum value among the multiple scaling factors.

[0090] Define the brightness gain value corresponding to pixel i as k i , and the scaling factor corresponding to pixel i as s i , and the target scaling factor as s max , then the brightness gain value corresponding to pixel i is:

[0091]

[0092] After obtaining the brightness gain values corresponding to all pixels or multiple pixels of the image to be projected, sort the brightness gain values corresponding to all pixels or multiple pixels of the image to be projected in ascending order to obtain a brightness gain sequence, and determine the target brightness gain value from the brightness gain sequence. First, define the brightness gain sequence as K with a length of N. Assuming that 0.001 of pixel brightness accurate display is abandoned, select the brightness gain value at the 0.001×N + 1th position in the brightness gain sequence K as the target brightness gain value.

[0093] In some embodiments, to ensure the stability of the display, define a maximum target brightness gain value to ensure that the target brightness gain value can never exceed the maximum target brightness gain value. The maximum target brightness gain value is k limit , then the target brightness gain value k t = MIN(k limit , k t ).

[0094] S203. Determine the first color space representation of the pixel of the image to be projected in the target color gamut according to the target brightness gain value and the second color space representation of the pixel of the image to be projected in the target color gamut.

[0095] The first color space representation of pixel i in the target color gamut is The brightness gain value corresponding to the pixel is k i , and the second color space representation of pixel i in the target color gamut is

[0096] The target brightness gain value is k t , then calculate for pixel i It can be calculated by calculation formula (6) The calculation formula (6) is as follows:

[0097]

[0098] In some embodiments, S203 may include: calculating a third color space representation of a pixel of the image to be projected in the target color gamut according to the target brightness gain value and the second color space representation of the pixel of the image to be projected in the target color gamut; if there is an element value less than a first value in the third color space representation of the pixel of the image to be projected in the target color gamut, replacing the element value less than the first value in the third color space representation with the first value to obtain a first color space representation of the pixel of the image to be projected in the target color gamut; if there is an element value greater than a second value in the third color space representation of the pixel of the image to be projected in the target color gamut, dividing each element value in the third color space representation of the pixel by the target element value, where the target element value is the largest element value in the third color space representation of the pixel, to obtain a first color space representation of the pixel of the image to be projected in the target color gamut.

[0099] The third color space representation of the pixel i of the image to be projected in the target color gamut can be calculated by formula (6), and the third color space representation is Each third color space representation includes three element values, which are respectively and If Then let be the first value, and the first value can be 0, that is, let If is greater than 1, then

[0100]

[0101] At this time, the first color space representation of pixel i

[0102] After the above processing, the pixel point results in the calculation result that are less than 0 and exceed 1, that is, exceed the modulation range of the spatial light modulator, can be processed, which can ensure the normal operation of the spatial light modulator and prevent bad pixels from appearing in the picture.

[0103] In this embodiment, by determining the brightness gain value, the light transmittance of the spatial light modulator can be further improved, so the brightness of the display screen is significantly increased, and the color of the image to be projected is accurately projected. Further, in this embodiment, the brightness gains of the pixel points are sorted, and then the target value of the brightness gain is determined through an empirical formula, which not only ensures the color restoration under the visible conditions of the human eye, but also further improves the display brightness of the projected image, ensures the stability of the system, reduces the calculation complexity at the same time, further reduces the cost of the projector, and at the same time, by limiting the maximum value of the target brightness gain value, the stability of the projected image is ensured.

[0104] In some embodiments, before S101, it includes: obtaining target pixel points from the image to be projected according to the brightness and color coordinates of each pixel point in the image to be projected.

[0105] Only when each pixel point in the image to be projected is represented in the xyY color space can the brightness and color coordinates of each pixel point be obtained. When represented in other color spaces, color space conversion needs to be performed on each pixel point to convert it to the xyY color space. If the other color space is not the XYZ color space, the XYZ color space can be used as an intermediate color space. First, convert the other color space to the XYZ color space, and then convert the XYZ color space to the xyY color space.

[0106] Taking the example that each pixel point is represented in the RGB color space, assuming the initial display color gamut is the BT.2020 color gamut, the BT.2020 color gamut is jointly determined by 3 base points and an equal-energy white point. The color coordinates of the four points are known, which are R(0.708, 0.292), G(0.170, 0.797), B(0.131, 0.046), W(0.3127, 0.3290). The color adaptation matrix M0 for color space conversion from the RGB color space to the XYZ color space can be obtained as follows:

[0107]

[0108] The XYZ color space representation [X i Y i Z i of pixel point i can be calculated by the calculation formula (7). The calculation formula (7) is as follows:

[0109] [X i Y i Z i = [r i g i b i · M0 (7),

[0110] Then, convert the XYZ color space to the xyY color space through the calculation formula (1). The xyY color space representation of pixel point i is:

[0111]

[0112] Thus, the brightness of pixel point i in the image to be projected can be obtained as Y i and the color coordinates

[0113]

[0114] In some embodiments, obtaining target pixel points from the image to be projected according to the brightness and color coordinates of each pixel point in the image to be projected includes: obtaining first pixel points whose color coordinates are not the target color coordinates from the image to be projected; screening out target pixel points with brightness higher than the brightness threshold from the first pixel points; the brightness threshold is determined based on the maximum brightness corresponding to the first pixel points.

[0115] Among them, the target color coordinates can be (0, 0). Obtaining first pixel points whose color coordinates are not the target color coordinates from the image to be projected is to remove black points from the image to be projected, and taking the remaining pixel points after removing the black points as the first pixel points. The set of the first pixel points can be represented by B, and the set of all pixel points on the image to be projected is represented by A.

[0116] Among them, the brightness threshold can be 1% of the maximum brightness lm_max in the first pixel points. Obtaining the maximum brightness lm_max of the pixel points in the set B, and screening out first pixel points with brightness higher than the brightness threshold from the first pixel points is to remove low-brightness points from the set C, and taking the remaining first pixel points after removing the low-brightness points as the target pixel points to obtain the set C.

[0117] Since the points with color coordinates of (0, 0) and low-brightness points do not have a strong visual impact on users, removing the above points before determining the target color gamut can reduce the amount of calculation, simplify the calculation, and at the same time avoid the invalidation of some algorithms due to the existence of abnormal points.

[0118] In some embodiments, before S101, it includes: filtering out color coordinate isolated points from the image to be projected according to the color coordinates of each pixel point in the image to be projected to obtain target pixel points.

[0119] Among them, the color coordinate isolated points refer to the points with relatively low density on the target color gamut image.

[0120] In some embodiments, a color gamut grid is constructed based on a preset step size and the color coordinate range corresponding to the initial color gamut; for each grid in the color gamut grid, the evaluation value of the grid is determined according to the number of pixel points whose color coordinates are located in the grid and the area of the grid in the image to be projected; the target grids in the color gamut grid with evaluation values higher than the preset evaluation value are obtained; and the first pixel points located in the target grids are taken as the target pixel points.

[0121] Among them, the preset step size can be set according to requirements. For example, the preset step size s = 0.001. Assuming that the color coordinate range corresponding to the initial color gamut is x ∈ (0.13, 0.71), y ∈ (0.04, 0.80), the color coordinate range is divided into a color gamut grid with the preset step size, and the color gamut grid includes multiple grids. Among them, the evaluation value of the grid can be the density of the first pixel points in the grid.

[0122] The number of the first pixel points in grid i is N i , the area of the grid is s2, and the density of grid i is wherein, the preset evaluation value may be the average density of the first pixel points of multiple grids included in the color gamut grid. The number of pixel points in set A is N C , the area of the initial color gamut is S, then the average density is wherein, c is a scaling factor and can take 0.01.

[0123] After obtaining the evaluation value of each grid in the color gamut grid and the preset evaluation value, compare the evaluation value of each grid with the preset evaluation value, and obtain the grids with the evaluation value higher than the preset evaluation value as the target grids.

[0124] Perform k-means filtering on the first pixel points in the grids in the color gamut grid except the target grids. k can be selected according to requirements. For example, k = 5. Obtain the remaining first pixel points after the filtering process, that is, the first pixel points in the target grids, as the target pixel points to obtain set D. Among them, K-means filtering means replacing each pixel value with the average value of K pixel values.

[0125] In some embodiments, the target pixel points may be the pixel points in the intersection of set C and set D. In some embodiments, since the outlier operation needs to process all points, and filtering out black points and low-brightness points after the outlier operation to be filtered is completed will increase the processing time. Correspondingly, filtering out black points and low-brightness points only needs to judge a single pixel point. Therefore, the operation of filtering out low-brightness points and black points can be performed first, and then the operation of filtering out outliers can be performed.

[0126] In this embodiment, by screening out low-brightness points, black points, and color coordinate outliers through the color coordinates and brightness of the pixel points, the situation where the color gamut cannot be reduced and the algorithm fails when inputting high-resolution and high-saturation images is avoided. At the same time, it is convenient to reduce the color gamut when determining the target color gamut, ensuring the stability of the determination of the target color gamut.

[0127] In some embodiments, as Figure 4 shown, S101 includes:[[]]

[0128] S301. Construct a color gamut closed figure that encloses the color coordinates of all target pixel points.

[0129] In some embodiments, the target pixel point closest to the base point of the initial color gamut in the target pixel points can be obtained as the vertex, and straight lines are connected to each vertex to form a color gamut closed figure.

[0130] In some other embodiments, the vertices can be directly fixed, and straight lines are used to connect the vertices to form a color gamut closed figure. The positions of the fixed vertices should ensure that the formed color gamut closed image covers the color coordinates of all target pixel points.

[0131] S302. Obtain the vertices of the color gamut closed image as the base points of the target color gamut.

[0132] After completing the construction of the color gamut closed figure, obtain the area within the color gamut bounding box as the target color gamut corresponding to the image to be projected, and the vertices of the color gamut closed figure are also the base points of the target color gamut.

[0133] In this embodiment, the color gamut bounding box includes the color coordinates of all target pixel points. The target color gamut determined according to the color gamut bounding box covers all the colors corresponding to the target pixel points, improving the adaptability between the target color gamut and the image to be projected. Therefore, the light source can emit light according to the image content without maintaining a fixed value, so the power consumption can be reduced and the brightness can be increased at the same time.

[0134] As Figure 5 shown, Figure 5 FIG. shows a structural block diagram of a projection control device in an embodiment of the present application. The device 600 includes a dynamic color gamut system 601 and a light source output calculation system 602. The dynamic color gamut system 601 includes a target pixel selection module 611 and a target color gamut selection module 612. Among them, the target pixel selection module 611 is used to convert all pixel points of the input image to be projected from the RGB color space to the xyY color space and perform filtering processing to obtain target pixel points; the target color gamut selection module 612 is used to construct a color gamut bounding box and determine the target color gamut corresponding to the image to be projected.

[0135] The light source output calculation system 602 includes a target color gamut light source representation generation module 621, a target color gamut pixel representation generation module 622, a brightness gain calculation module 623, a global gray scale adjustment module 624, and a light source brightness-current mapping module 625. Among them, the target color gamut light source representation generation module 621 is used to calculate the linear programming combination representation of multiple light sources, that is, the conversion coefficient, according to the base points of the target color gamut; the target color gamut pixel representation generation module 622 is used to calculate the second color space representation of all target pixel points in the target color gamut; the brightness gain calculation module 623 is used to determine the target brightness gain value and obtain the first color space representation after the brightness gain of all pixels; the global gray scale adjustment module 624 is used to count the maximum value of the first color space representation of all pixels in each color segment. If it is less than 1.0, it is scaled to 1.0, and the power representation of the corresponding base point is scaled accordingly, and then output to the spatial light modulation device (such as DMD); the light source brightness-current mapping module 625 is used to convert the target light source combination representation of all base points in the new color gamut into the input current actually required by the light source and send it to the light source current control device.

[0136] See the appendix Figure 6 , Figure 6 FIG. shows the structural block diagram of another projection control device proposed in an embodiment of the present application, which is used for a projector including multiple light sources. The device 600 includes:

[0137] The first determination module 610 is used to determine the base points of the target color gamut corresponding to the image to be projected according to the color coordinates of the target pixel points in the image to be projected;

[0138] The second determination module 620 is used to determine the conversion coefficient between the color space representation of multiple light sources and the color space representation of the base points of the target color gamut;

[0139] The third determination module 630 is used to determine the first color space representation of the pixel points of the image to be projected in the target color gamut according to the initial color space representation of the pixel points of the image to be projected and the color space representation of the base points of the target color gamut;

[0140] The fourth determination module 640 is used to determine the adjustment factor of the image to be projected according to the first color space representation of the pixel points of the image to be projected in the target color gamut;

[0141] The fifth determination module 650 is used to determine the target color space representation of the pixel points of the image to be projected according to the adjustment factor of the image to be projected and the first color space representation of the pixel points in the target color gamut;

[0142] The sixth determination module 660 is used to determine the target light source combination representation of the base points of the target color gamut according to the adjustment factor of the image to be projected and the conversion coefficient;

[0143] A projection module 670, configured to control a projector to project a to-be-projected image according to a target color space representation of pixel points of the to-be-projected image and a target light source combination representation of a base point.

[0144] Optionally, the third determination module 630 is further configured to calculate a second color space representation of pixel points of the to-be-projected image in a target color gamut according to an initial color space representation of pixel points of the to-be-projected image, a color space representation of a base point of the target color gamut, and duty ratios of respective multiple light-emitting color segments corresponding to the projector; determine a target brightness gain value according to the second color space representation of pixel points of the to-be-projected image in the target color gamut; and determine a first color space representation of pixel points of the to-be-projected image in the target color gamut according to the target brightness gain value and the second color space representation of pixel points of the to-be-projected image in the target color gamut.

[0145] Optionally, the third determination module 630 is further configured to determine a scaling factor corresponding to each pixel point according to the second color space representation of pixel points of the to-be-projected image in the target color gamut; determine a target scaling factor according to the scaling factors corresponding to pixel points of the to-be-projected image; determine a brightness gain value corresponding to each pixel point according to the target scaling factor and the scaling factors corresponding to each pixel point; arrange the brightness gain values corresponding to pixel points of the to-be-projected image in ascending order to obtain a brightness gain sequence; and determine a target brightness gain value from the brightness gain sequence.

[0146] Optionally, the third determination module 630 is further configured to calculate a third color space representation of pixel points of the to-be-projected image in the target color gamut according to the target brightness gain value and the second color space representation of pixel points of the to-be-projected image in the target color gamut; if there are element values less than a first value in the third color space representation of pixel points of the to-be-projected image in the target color gamut, replace the element values less than the first value in the third color space representation with the first value to obtain a first color space representation of pixel points of the to-be-projected image in the target color gamut; if there are element values greater than a second value in the third color space representation of pixel points of the to-be-projected image in the target color gamut, divide each element value in the third color space representation of the pixel points by a target element value to obtain a first color space representation of pixel points of the to-be-projected image in the target color gamut, where the target element value is the largest element value in the third color space representation of the pixel points.

[0147] Optionally, the first determination module 610 is further configured to obtain target pixel points from the to-be-projected image according to the brightness and color coordinates of each pixel point in the to-be-projected image.

[0148] Optionally, the first determination module 610 is further configured to obtain first pixel points whose color coordinates are not the target color coordinates from the to-be-projected image; screen out target pixel points with brightness higher than a brightness threshold from the first pixel points; and the brightness threshold is determined based on the maximum brightness corresponding to the first pixel points.

[0149] Optionally, the first determination module 610 is further configured to filter out color coordinate isolated points from the image to be projected according to the color coordinates of each pixel point in the image to be projected, so as to obtain target pixel points.

[0150] Optionally, the first determination module 610 is further configured to construct a color gamut grid based on a preset step size and the color coordinate range corresponding to the initial color gamut; for each grid in the color gamut grid, determine an evaluation value of the grid according to the number of pixel points whose color coordinates are located in the grid and the area of the grid in the image to be projected; obtain target grids in the color gamut grid whose evaluation values are higher than a preset evaluation value; and obtain first pixel points located in the target grids as target pixel points.

[0151] Optionally, the first determination module 610 is further configured to construct a color gamut closed figure surrounding the color coordinates of all target pixel points; and obtain the vertices of the color gamut closed image as the base points of the target color gamut.

[0152] Optionally, the number of light sources of the projector is greater than the number of color segments of the projector. The second determination module 620 is further configured to construct an equation of conversion coefficients according to the color space representation of the base points of the target color gamut and the color space representations of multiple light sources; and solve the equation by a linear programming method to obtain the conversion coefficients.

[0153] Those skilled in the art can clearly understand that for the convenience and conciseness of description, the specific working processes of the above-described devices and modules can refer to the corresponding processes in the foregoing method embodiments, and will not be described herein again.

[0154] In addition, the functions in the embodiments of the present application can be integrated in one processing module, or each module can exist physically alone, or two or more modules can be integrated in one module. The above-integrated modules can be implemented in the form of hardware or in the form of software function modules.

[0155] Please refer to Figure 7 , Figure 7 FIG. shows a structural block diagram of a projector according to an embodiment of the present application. The projector 500 may include one or more of the following components: a processor 510, a memory 520, and one or more application programs, where one or more application programs may be stored in the memory 520 and configured to be executed by one or more processors 510, and the one or more programs are configured to execute the methods described in the foregoing method embodiments.

[0156] The processor 510 may include one or more processing cores. The processor 510 is connected to various parts within the entire projector 500 through various interfaces and lines. By running or executing instructions, programs, code sets, or instruction sets stored in the memory 520, and by calling data stored in the memory 520, it performs various functions of the projector 500 and processes data. Optionally, the processor 510 may be implemented in at least one hardware form of digital signal processing (DSP), field-programmable gate array (FPGA), or programmable logic array (PLA). The processor 110 may integrate a combination of one or several of a central processing unit (CPU), a graphics processing unit (GPU), and a modem, etc. Among them, the CPU mainly processes the operating system, user interface, application programs, etc.; the GPU is responsible for rendering and drawing the display content; the modem is used to process wireless communication. It can be understood that the above-mentioned modem may not be integrated into the processor 510 and may be implemented separately through a communication chip.

[0157] The memory 520 may include random access memory (RAM) and may also include read-only memory. The memory 520 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 520 may include a program storage area and a data storage area. Among them, the program storage area may store instructions for implementing the operating system, instructions for implementing at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the following various method embodiments, etc. The data storage area may also store data created during the use of the terminal 500 (such as phone book, audio and video data, chat record data, etc.).

[0158] In addition, in each embodiment of the present application, each function may be integrated in a processing module, or each module may exist physically alone, or two or more modules may be integrated in one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software function modules.

[0159] Please refer to Figure 8 , Figure 8 which shows a structural block diagram of a computer-readable storage medium according to an embodiment of the present application. Program code is stored in the computer-readable medium 700, and the program code can be called by a processor to execute the methods described in the above method embodiments.

[0160] The computer-readable storage medium 700 can be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read-only memory), an EPROM, a hard disk, or a ROM. Optionally, the computer-readable storage medium 700 includes a non-transitory computer-readable storage medium. The computer-readable storage medium 700 has a storage space for program code 710 that executes any of the method steps in the above-described method. These program codes can be read out from or written into one or more computer program products. The program code 710 can be compressed in a suitable form, for example.

[0161] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A projection control method, characterized in that, For a projector including a plurality of light sources, the method includes: Determining a base point of a target color gamut corresponding to the image to be projected according to the color coordinates of target pixel points in the image to be projected; Determining a conversion coefficient between the color space representation of the plurality of light sources and the color space representation of the base point of the target color gamut; Determining a first color space representation of the pixel points of the image to be projected in the target color gamut according to the initial color space representation of the pixel points of the image to be projected and the color space representation of the base point of the target color gamut; Determining an adjustment factor of the image to be projected according to the first color space representation of the pixel points of the image to be projected in the target color gamut; Determining a target color space representation of the pixel points of the image to be projected according to the adjustment factor of the image to be projected and the first color space representation of the pixel points in the target color gamut; Determining a target light source combination representation of the base point of the target color gamut according to the adjustment factor of the image to be projected and the conversion coefficient; Controlling the projector to project the image to be projected according to the target color space representation of the pixel points of the image to be projected and the target light source combination representation of the base point.

2. The method according to claim 1, wherein The projector has a plurality of light-emitting color segments, and the adjustment factor includes adjustment coefficients corresponding to different light-emitting color segments respectively.

3. The method according to claim 2, wherein The determining a first color space representation of the pixel points of the image to be projected in the target color gamut according to the initial color space representation of the pixel points of the image to be projected and the color space representation of the base point of the target color gamut includes: Calculating a second color space representation of the pixel points of the image to be projected in the target color gamut according to the initial color space representation of the pixel points of the image to be projected, the color space representation of the base point of the target color gamut, and the duty ratio of each of the plurality of light-emitting color segments corresponding to the projector; Determining a target brightness gain value according to the second color space representation of the pixel points of the image to be projected in the target color gamut; Determining a first color space representation of the pixel points of the image to be projected in the target color gamut according to the target brightness gain value and the second color space representation of the pixel points of the image to be projected in the target color gamut.

4. The method according to claim 3, characterized in that, The determining a target brightness gain value according to the second color space representation of the pixel points of the image to be projected in the target color gamut includes: Determining a scaling factor corresponding to each pixel point according to the second color space representation of the pixel points of the image to be projected in the target color gamut; Determining a target scaling factor according to the scaling factor corresponding to the pixel points of the image to be projected; Determining a brightness gain value corresponding to each pixel point according to the target scaling factor and the scaling factor corresponding to each pixel point; Arranging the brightness gain values corresponding to the pixel points of the image to be projected in ascending order to obtain a brightness gain sequence; Determining a target brightness gain value from the brightness gain sequence.

5. The method according to claim 4, characterized in that The determining a first color space representation of the pixel points of the image to be projected in the target color gamut according to the target brightness gain value and the second color space representation of the pixel points of the image to be projected in the target color gamut includes: Calculate a third color space representation of a pixel of the image to be projected in the target color gamut according to the target brightness gain value and the second color space representation of the pixel of the image to be projected in the target color gamut; If there is an element value less than a first value in the third color space representation of a pixel of the image to be projected in the target color gamut, replace the element value less than the first value in the third color space representation with the first value to obtain a first color space representation of the pixel of the image to be projected in the target color gamut; If there is an element value greater than a second value in the third color space representation of a pixel of the image to be projected in the target color gamut, divide each element value in the third color space representation of the pixel by a target element value to obtain a first color space representation of the pixel of the image to be projected in the target color gamut, where the target element value is the largest element value in the third color space representation of the pixel; 6. The method according to claim 1, wherein Before determining the target color gamut corresponding to the image to be projected according to the color coordinates of a target pixel in the image to be projected, the method further includes: Obtain a target pixel from the image to be projected according to the brightness and color coordinates of each pixel in the image to be projected; 7. The method according to claim 6, characterized in that The obtaining a target pixel from the image to be projected according to the brightness and color coordinates of each pixel in the image to be projected includes: Obtain a first pixel whose color coordinates are not the target color coordinates from the image to be projected; Screen out target pixels with brightness higher than a brightness threshold from the first pixels; the brightness threshold is determined based on the maximum brightness corresponding to the first pixels; 8. The method according to claim 1, wherein Before determining the target color gamut corresponding to the image to be projected according to the color coordinates of a target pixel in the image to be projected, the method further includes: Perform a filtering process on color coordinate outliers of the image to be projected according to the color coordinates of each pixel in the image to be projected to obtain a target pixel; 9. The method according to claim 8, wherein The performing a filtering process on color coordinate outliers of the image to be projected according to the color coordinates of each pixel in the image to be projected to obtain a target pixel includes: Construct a color gamut grid based on a preset step size and the color coordinate range corresponding to the initial color gamut; For each grid in the color gamut grid, determine an evaluation value of the grid according to the number of pixels in the image to be projected whose color coordinates are located in the grid and the area of the grid; Obtain target grids in the color gamut grid whose evaluation values are higher than a preset evaluation value; Obtain first pixels located in the target grids as target pixels; 10. The method according to claim 1, wherein The determining the target color gamut corresponding to the image to be projected according to the color coordinates of a target pixel in the initial color gamut includes: Construct a color gamut closed figure surrounding the color coordinates of all target pixels; Obtain the vertices of the color gamut closed image as the base points of the target color gamut; 11. The method according to claim 1, wherein The number of light sources of the projector is greater than the number of color segments of the projector; The determining conversion coefficients between the color space representations of the multiple light sources and the color space representations of the base points of the target color gamut includes: Construct an equation for the conversion coefficient based on the color space representations of the base points of the target color gamut and the color space representations of multiple light sources; Solve the equation by linear programming to obtain the conversion coefficient.

12. The method according to claim 11, wherein The constraint condition of the linear programming method is that the conversion coefficient is between 0 and 1, and the optimization objective of the linear programming method is to maximize the conversion coefficient.

13. A projection control device, characterized in that, For a projector including multiple light sources, the device includes: A first determination module, configured to determine the base points of the target color gamut corresponding to the image to be projected according to the color coordinates of the target pixel points in the image to be projected; A second determination module, configured to determine the conversion coefficient between the color space representation of the multiple light sources and the color space representation of the base points of the target color gamut; A third determination module, configured to determine the first color space representation of the pixel points of the image to be projected in the target color gamut according to the initial color space representation of the pixel points of the image to be projected and the color space representation of the base points of the target color gamut; A fourth determination module, configured to determine the adjustment factor of the image to be projected according to the first color space representation of the pixel points of the image to be projected in the target color gamut; A fifth determination module, configured to determine the target color space representation of the pixel points of the image to be projected according to the adjustment factor of the image to be projected and the first color space representation of the pixel points in the target color gamut; A sixth determination module, configured to determine the target light source combination representation of the base points of the target color gamut according to the adjustment factor of the image to be projected and the conversion coefficient; A projection module, configured to control the projector to project the image to be projected according to the target color space representation of the pixel points of the image to be projected and the target light source combination representation of the base points.

14. A projector, characterized in that, Including: One or more processors; A memory; One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the one or more processors, and the one or more applications are configured to execute the method according to any one of claims 1-12.

15. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores program code executable by a processor, and when the program code is executed by the processor, the processor executes the method according to any one of claims 1-12.

Images