CN117011134B - Direct scaling method for display sub-pixel diamond arrangement image - Google Patents

Abstract

The invention discloses a direct scaling method for display sub-pixel diamond arrangement images, which comprises the following steps: determining a reference pixel point set of each sub-pixel with new resolution, wherein the reference pixel point set comprises a plurality of rows and columns which are obliquely arranged and reference pixel points which actually exist under the original resolution; determining an oblique equivalent phase (x _s,y_s) according to the positional relationship of the sub-pixel relative to the reference pixel point set; the oblique equivalent phase is: the pixel points which are actually existed under the original resolution are taken as equivalent phases in a rotation coordinate system of the lattice points; and calculating the interpolation brightness Z _s of the sub-pixel according to the oblique equivalent phase and the brightness value of each pixel point of the reference pixel point set. According to the invention, for the image data with sub-pixel diamond arrangement, bicubic interpolation processing is directly and accurately carried out by selecting the pixel points which are obliquely arranged, so that complex anti-SPR and SPR operation can be avoided on the driving chip, and the power consumption, the area and the manufacturing cost of the driving chip are greatly saved.

Description

A direct scaling method for display sub-pixel diamond arrangement images

Technical Field

The present invention belongs to the technical field of displays, and in particular relates to a direct scaling method for a diamond-arranged image of sub-pixels of a display.

Background Art

As shown in Figure 1, most OLED displays currently use a diamond-shaped arrangement of sub-pixels, represented by the Pentile arrangement. This method reduces the density of sub-pixels while ensuring display quality, thereby reducing process difficulty and cost. This arrangement does not correspond to the number of sub-pixels of the three colors, Green sub-pixel 1, Red sub-pixel 2, and Blue sub-pixel 3. When displayed, the number of G sub-pixels is usually twice the number of R or B. In this case, the input signal source can be reduced to 2/3 of the original data, or the original 100% data can be maintained but the spatial rendering (SPR—Sub Pixel Rendering) of the sub-pixel arrangement can be re-performed on the display driver chip. For example, Apple phones use the former transmission solution, while most Android phones use the latter.

In some specific use cases, it is necessary to scale the display image resolution, such as when the input data resolution is different from the display resolution, or when some algorithm processing requires interpolation of the input image data. For input signals with the same number of RGB sub-pixels, traditional scaling interpolation processing usually uses bi-cubic interpolation and other processing, but for input that has been subjected to sub-pixel spatial rendering (SPR) (hereinafter referred to as SPR input data), the usual practice is to restore it to the complete image data (same number of RGB), then perform the above interpolation processing, and finally perform sub-pixel spatial rendering (SPR) processing again.

For the SPR input data, the number of green sub-pixels is consistent with the screen resolution, so when scaling the resolution (Scaling), it can be directly processed by interpolation. Usually, bi-cubic interpolation has a better effect and is more commonly used.

For the red and blue sub-pixels, they are arranged in a diamond shape, and the number is half of the screen resolution. The traditional scaling method, as shown in Figures 2A to 2E, requires first filling in the missing half of the sub-pixels, a step called anti-SPR. In this way, the number of red and blue sub-pixels is the same as that of green, and they correspond one to one. Next, you can directly use bicubic interpolation (Bi-Cubic) processing. After the scaling process is completed, the scaled data must also be subjected to SPR processing before it can be correctly displayed on the display. In the figure, the sub-pixel 4 of the original image is represented by a shaded diamond, the filled sub-pixel 5 is represented by a hollow diamond, and the scaled target sub-pixel 6 is represented by a black diamond.

The prior art has the following three disadvantages:

1. The anti-SPR step of padding pixels and the SPR step after scaling will introduce additional errors, and the quality of the SPR algorithm is directly related to the quality of the display;

2. The whole process is lengthy and complicated, and occupies a high area and power consumption burden of the display driver chip.

Summary of the invention

In view of this, an object of the present invention is to provide a direct scaling method for a display sub-pixel diamond-arranged image. For the image data of the sub-pixel diamond-arranged image, bicubic interpolation processing is directly and accurately performed by selecting obliquely arranged pixel points, thereby avoiding complex anti-SPR and SPR operations in the driver chip, thereby greatly saving the power consumption, area and manufacturing cost of the driver chip.

The technical problem to be solved by the present invention is to provide a method for directly obliquely selecting a reference pixel point set in the SPR input data for interpolation and scaling, as shown in Figures 3A to 3C, the method is direct and concise, and minimizes additional errors and overhead. For the bicubic interpolation algorithm commonly used for interpolation and scaling, it is usually required that the X and Y directions are orthogonal. First, the interpolation result in the X direction is calculated, and then the interpolation result in the Y direction is calculated. For sub-pixels arranged in a diamond shape, because the phases of the odd and even rows are staggered, it is obviously not applicable to the conventional bicubic algorithm. The present invention rotates the reference coordinate axis of the actual sub-pixel by 45°, and the new X and Y directions are orthogonal again after rotation, so the conventional bicubic algorithm is fully applicable.

To achieve the above object, the present invention provides a direct scaling method for a display sub-pixel diamond arrangement image, comprising the following steps:

Step S1: determining a reference pixel point set for each sub-pixel of the new resolution, wherein the reference pixel point set includes a number of rows and a number of columns of reference pixel points that actually exist at the original resolution and are arranged obliquely;

Step S2: determining an oblique equivalent phase ( _xs , _ys ) according to the positional relationship of the sub-pixel relative to the reference pixel point set; the oblique equivalent phase is: an equivalent phase in a rotating coordinate system with the actual pixel points at the original resolution as grid points;

Step S3: Calculate the interpolated brightness Z _s of the sub-pixel according to the oblique equivalent phase and the brightness value of each pixel point in the reference pixel point set.

Preferably, step S1 specifically includes steps S1.1 to S1.3:

Step S1 specifically includes steps S1.1 to S1.3:

Step S1.1: Obtaining the size ratios of the new resolution in the x direction and the original resolution in the y direction, namely, ratio _x and ratio _y ;

Step S1.2: For each sub-pixel of the new resolution, calculate the integer part (x _t , y _t ) and the fractional part (Δx _t , Δy _t ) of its coordinate position at the original resolution;

Step S1.3: The pixel grid corresponding to the integer part (x _t , y _t ) of the coordinate position described in step S1.2 is the first pixel grid;

According to the connection lines of the real pixel points at the original resolution at the vertices of the first pixel grid, the first pixel grid is divided into two triangular areas, the two triangular areas include a first triangular area and a second triangular area; according to the arrangement of the two triangular areas and the situation that the sub-pixel is located in the first triangular area or the second triangular area, the coordinate reference value (x ₀ , y ₀ ) is calculated;

The coordinate reference value (x ₀ , y ₀ ) is the coordinate reference of the reference pixel point;

Step S2 specifically comprises: obtaining the oblique equivalent phase ( _xs , _ys ) according to the decimal part of the coordinate position (Δxt, Δyt), the arrangement of the two triangular regions in step S3, and the situation _that the sub-pixel is located in the first triangular region or the second triangular region, wherein the oblique equivalent phase ( _{xs , ys} ) is the decimal part of the coordinate value corresponding to the sub-pixel in the rotating coordinate system;

Step S3 specifically includes steps S3.1 to S3.3:

Step S3.1: Obtain the brightness value of each pixel in the reference pixel set;

Step S3.2: Calculating a weight value corresponding to the brightness value of the pixel point according to the oblique equivalent phase (x _s , y _s );

Step S3.3: Calculate the interpolated brightness Z _s of the sub-pixel according to the weight value and the brightness value of the pixel point.

Preferably, the arrangement of the two triangular regions in step S1.3 and the situation where the sub-pixel is located in the first triangular region or the second triangular region specifically include:

Case 1: the first triangular area is located at the upper right of the first pixel grid, the second triangular area is located at the lower left of the first pixel grid, and the sub-pixel is located in the second triangular area;

Second situation: the first triangular area is located at the upper left of the first pixel grid, the second triangular area is located at the lower right of the first pixel grid, and the sub-pixel is located in the second triangular area;

The third situation: the first triangular area is located at the upper right of the first pixel grid, the second triangular area is located at the lower left of the first pixel grid, and the sub-pixel is located in the first triangular area;

Fourth situation: the first triangular area is located at the upper left of the first pixel grid, the second triangular area is located at the lower right of the first pixel grid, and the sub-pixel is located in the first triangular area.

Preferably, the calculation of the coordinate reference value (x ₀ , y ₀ ) in step S1.3 is specifically to calculate the coordinate reference value (x ₀ , y ₀ ) according to formula (1) and formula (2):

x ₀ = x _t -2-p (1);

y ₀ =y _t -2-q (2);

Among them: p is 1 in the first and fourth cases, and is 0 in the second and third cases; q is 0 in the first and second cases, and is 1 in the third and fourth cases.

Preferably, the reference pixel set includes 16 reference pixel points, and the coordinate values of the reference pixel points are expressed as coordinate reference values (x ₀ , y ₀ ), which are respectively:

(x ₀ +0,y ₀ +3), (x ₀ +1,y ₀ +2), (x ₀ +2,y ₀ +1), (x ₀ +3,y ₀ +0), (x ₀ +1,y ₀ +4), (x ₀ +2,y ₀ +3), (x ₀ +3,y ₀ +2), (x ₀ +4,y ₀ +1), (x ₀ + 2,y ₀ +5), (x ₀ +3,y ₀ +4), (x ₀ +4,y ₀ +3), (x ₀ +5,y ₀ +2), (x ₀ +3, y ₀ +6), (x ₀ +4, y ₀ +5), (x ₀ +5, y ₀ +4), (x ₀ +6, y ₀ +3).

Preferably, step S2 specifically includes:

The oblique equivalent phase (x _s ,y _s ) is calculated according to formula (3) and formula (4):

The values of p and q are the same as those in step S1.3.

Preferably, step S3.2 is specifically:

The weight values include an x-direction weight value and a y-direction weight value;

Calculate the x-direction weight value corresponding to the reference pixel point according to xs and the filter basis function; calculate the y-direction weight value corresponding to the reference pixel point according to _ys and the filter basis function; the product of the x _- direction weight value and the corresponding y-direction weight value is the weight value of the corresponding reference pixel point;

The filter basis function is formula (5):

In the formula: a is a preset parameter, x is the x _- direction or y-direction position of the reference pixel point relative to the sub-pixel calculated according to xs or _ys , corresponding to the calculation of the x-direction weight value and the y-direction weight value, respectively.

Preferably, the number of the reference pixels is 16, and the pixel brightness values form a pixel brightness value matrix Z according to formula (6);

Wherein, Z(x,y) represents the brightness value of the pixel corresponding to the reference pixel with coordinates (x,y), and the coordinates of the reference pixel are all represented by the coordinate reference value (x ₀ ,y ₀ );

The x-direction weight values form an x-direction row weight coefficient vector W _x ; the y-direction weight values form a y-direction row weight coefficient vector W _y ; the step S3.3 specifically calculates the brightness value Z _s of the sub-pixel by matrix multiplication according to formula (7);

The beneficial effect of the present invention is that for image data with sub-pixels arranged in a diamond shape, bicubic interpolation processing is directly and accurately performed by selecting obliquely arranged pixel points, thereby avoiding complex anti-SPR and SPR operations in the driver chip, greatly saving the power consumption, area and manufacturing cost of the driver chip.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a schematic diagram of a sub-pixel arrangement in the prior art;

2A to 2E are schematic diagrams of a process of processing red and blue sub-pixels in the prior art;

3A to 3C are schematic diagrams of a process of processing red and blue sub-pixels according to the present invention;

4A to 4D are schematic diagrams of specific situations of the arrangement of the triangular regions of the present invention;

1Green sub-pixel; 2Red sub-pixel; 3Blue sub-pixel; 4Sub-pixel of the original image; 5Padded sub-pixel; 6Target sub-pixel after scaling; 7Sub-pixel at the new resolution; 8First triangular area; 9Second triangular area.

DETAILED DESCRIPTION

One of the core points of the present invention is to provide a direct scaling method for images with diamond-shaped sub-pixels arranged on a display. For image data with diamond-shaped sub-pixels, bicubic interpolation (or other interpolation methods) is directly and accurately performed by selecting obliquely arranged pixel points, thereby avoiding complex anti-SPR and SPR operations in the driver chip, greatly saving the power consumption, area and manufacturing cost of the driver chip.

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

The direct scaling method for the diamond-shaped arrangement of sub-pixels of the display disclosed in this embodiment is applied to the driver chips of OLED display screens, Mini LED display screens and future Micro LED display screens. The direct scaling method disclosed in this embodiment includes the following steps:

Step S1: determining a reference pixel point set for each sub-pixel of the new resolution, wherein the reference pixel point set includes a number of rows and a number of columns of reference pixel points that actually exist at the original resolution and are arranged obliquely;

Specifically, it includes: 1. Obtaining the size ratios (ratio _x) and (ratio _y) of the new resolution in the x-direction and y-direction relative to the original resolution; determining the resolution and geometric dimensions of the input SPR data, recorded as a unit length, that is, both the length and width are "1" (because the length and width need to be calculated separately, the length and width can be different, but they are both a unit length in their respective dimensions), and on this basis determining the size of the new resolution after scaling.

2. For each sub-pixel 7 of the new resolution, calculate the integer part (x _t , y _t ) and the fractional part (Δx _t , Δy _t ) of its coordinate position at the original resolution; for example, for the (m,n)th sub-pixel of the new resolution, its position is (m×ratio _x ,n×ratio _y ), calculate its position and offset at the original resolution, that is:

Where: x _t and y _t are integers; Δx _t , Δy _t ∈[0,1]; that is, the position is divided into integer and decimal parts.

3. The pixel grid corresponding to the integer part of the coordinate position (x _t , y _t ), that is, the pixel grid with four vertex coordinates {(x _t , y _t ), (x _t +1, y _t ), (x _t , y _t +1), (x _t +1, y _t +1)}, is recorded as the first pixel grid; the current target sub-pixel falls within the first pixel grid;

According to the connection lines of the real pixel points at the original resolution at the vertices of the first pixel grid, the first pixel grid is divided into two triangular areas, and the two triangular areas include a first triangular area 8 and a second triangular area 9; for example, for the SPR data, if it is a red sub-pixel, generally when _xt and _yt have the same parity, it is the position of the real pixel point, that is, {( _xt , _yt ), ( _{xt +} 1, yt+1)}, as shown in FIG4A or FIG4C; for the blue sub-pixel, generally when _xt and _yt have different parities, it is the position of the real pixel point, that is, {( _xt +1, _yt ), ( _xt , _yt +1)}, as shown in FIG4B or FIG4D.

Furthermore, the coordinate reference value (x ₀ , y ₀ ) is calculated according to the arrangement of the two triangular areas and whether the sub-pixel is located in the first triangular area or the second triangular area. In the present embodiment, the coordinate reference value (x ₀ , y ₀ ) is defined as the coordinate value of the upper left corner of a 7×7 square area defined by 4×4 reference pixels selected obliquely in the coordinate system before rotation. In other embodiments, other positions may also be used as the coordinate reference value.

The coordinates of each reference pixel point can be expressed by the position of the relative coordinate reference value, which in this embodiment are:

(x ₀ +0,y ₀ +3), (x ₀ +1,y ₀ +2), (x ₀ +2,y ₀ +1), (x ₀ +3,y ₀ +0), (x ₀ +1,y ₀ +4), (x ₀ +2,y ₀ +3), (x ₀ +3,y ₀ +2), (x ₀ +4,y ₀ +1), (x ₀ + 2,y ₀ +5), (x ₀ +3,y ₀ +4), (x ₀ +4,y ₀ +3), (x ₀ +5,y ₀ +2), (x ₀ +3, y ₀ +6), (x ₀ +4, y ₀ +5), (x ₀ +5, y ₀ +4), (x ₀ +6, y ₀ +3).

When calculating the coordinate reference value (x ₀ , y ₀ ), there are four cases as shown in FIG. 4A to FIG. 4D :

Case 1: As shown in FIG. 4A , the first triangular area 8 is located at the upper right of the first pixel grid, the second triangular area 9 is located at the lower left of the first pixel grid, and the sub-pixel is located in the second triangular area;

Second situation: as shown in FIG4B , the first triangular area 8 is located at the upper left of the first pixel grid, the second triangular area 9 is located at the lower right of the first pixel grid, and the sub-pixel is located in the second triangular area;

The third situation: as shown in FIG4C , the first triangular area 8 is located at the upper right of the first pixel grid, the second triangular area 9 is located at the lower left of the first pixel grid, and the sub-pixel is located in the first triangular area;

Fourth situation: as shown in FIG4D , the first triangular area 8 is located at the upper left of the first pixel grid, the second triangular area 9 is located at the lower right of the first pixel grid, and the sub-pixel is located in the first triangular area;

Calculate the pixel coordinate reference value (x ₀ ,y ₀ ) according to formula (1) and formula (2):

x ₀ = x _t -2-p (1);

y ₀ =y _t -2-q (2);

Among them: p is 1 in the first and fourth cases, and is 0 in the second and third cases; q is 0 in the first and second cases, and is 1 in the third and fourth cases.

Step S2: According to the decimal part of the coordinate position (Δx _t , Δy _t ) and the classification of the first to fourth cases, the oblique equivalent phase (x _s , y _s ) of the sub-pixel in the rotating coordinate system with the pixel points actually existing at the original resolution as grid points is obtained. The oblique equivalent phase (x _s , y _s ) is the decimal part of the coordinate value corresponding to the sub-pixel in the rotating coordinate system. The specific process is to calculate the equivalent phase (x _s , y _s ) according to formula (3) and formula (4):

Among them, the values of p and q are the same as those in the previous steps;

Substituting the values of p and q into this equation, we get:

In the first case,

In the second case,

In the third case,

In the fourth case,

Step S3: calculating the interpolated brightness Z _s of the sub-pixel according to the oblique equivalent phase and the brightness value of each pixel point of the reference pixel point set, specifically comprising:

1. Get the brightness values of 16 pixels corresponding to 16 reference pixels.

2. Calculate the weight values corresponding to the brightness values of the 16 pixels according to the oblique equivalent phase ( _xs , _ys ), which are divided into the x-direction weight value and the y-direction weight value. Here, the x-direction and the y-direction are the horizontal and vertical directions in the rotated coordinate system (for the original coordinate system, they are oblique directions); the total weight values corresponding to the brightness values of the 16 pixels are the products of the corresponding x-direction weight values and the y-direction weight values;

The filter basis function used to calculate the weight value is formula (5):

In the formula: a is a preset parameter, x is the x _- direction or y-direction position of the reference pixel point relative to the sub-pixel calculated according to xs or _ys , corresponding to the calculation of the x-direction weight value and the y-direction weight value, respectively.

Using the matrix calculation method, the obtained x-direction weight values form the x-direction row weight coefficient vector _Wx , that is, _Wx = ( _Wx0 , _Wx1 , _Wx2 , _Wx3 ); the y-direction weight values form the y-direction row weight coefficient vector _Wy , that is, _Wy = ( _Wy0 , _Wy1 , _Wy2 , _Wy3 ).

3. Calculate the brightness value Z _s of the sub-pixel according to the weight value and the brightness value of the pixel point; using the matrix calculation method, the brightness values of the 16 pixels form a pixel brightness value matrix Z according to formula (6);

Calculate the brightness value Z _s of the sub-pixel by matrix multiplication according to formula (7);

In this embodiment, during the actual test of a certain OLED display screen, the specific example is as follows:

1. A certain OLED display screen integrates a display driver chip using the algorithm of the present invention;

2. Set appropriate ratio _x and ratio _y according to the input data and the size and resolution of the display to be driven, or according to the resolution required by other IPs;

3. Quantize Δx _t and Δy _t to 4-bit precision, pre-calculate the filter coefficients of each phase, and store them in the display driver chip;

4. Calculate Δx _t and Δy _t of each target sub-pixel, determine which of the situations in FIG. 4A to FIG. 4D it belongs to, and select the corresponding coordinate reference value;

5. Calculate the interpolated brightness of the current sub-pixel through matrix operations.

6. Output after scaling is completed.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims (7)

1. A direct scaling method for a display sub-pixel diamond arrangement image, characterized by comprising the following steps: Step S1: determining a reference pixel point set for each sub-pixel of the new resolution, wherein the reference pixel point set includes a number of rows and a number of columns of reference pixel points that actually exist at the original resolution and are arranged obliquely; Step S2: determining an oblique equivalent phase ( _xs , _ys ) according to the positional relationship of the sub-pixel relative to the reference pixel point set; the oblique equivalent phase is: an equivalent phase in a rotating coordinate system with the actual pixel points at the original resolution as grid points; Step S3: calculating the interpolated brightness Z _s of the sub-pixel according to the oblique equivalent phase and the brightness value of each pixel point of the reference pixel point set; Step S1 specifically includes steps S1.1 to S1.3: Step S1.1: Obtaining the size ratios of the new resolution in the x direction and the original resolution in the y direction, namely, ratio _x and ratio _y ; Step S1.2: For each sub-pixel of the new resolution, calculate the integer part (x _t , y _t ) and the fractional part (Δx _t , Δy _t ) of its coordinate position at the original resolution; Step S1.3: The pixel grid corresponding to the integer part (x _t , y _t ) of the coordinate position described in step S1.2 is the first pixel grid; According to the connection lines of the real pixel points at the original resolution at the vertices of the first pixel grid, the first pixel grid is divided into two triangular areas, the two triangular areas include a first triangular area and a second triangular area; according to the arrangement of the two triangular areas and the situation that the sub-pixel is located in the first triangular area or the second triangular area, the coordinate reference value (x ₀ , y ₀ ) is calculated; The coordinate reference value (x ₀ , y ₀ ) is the coordinate reference of the reference pixel point; Step S2 specifically comprises: obtaining the oblique equivalent phase ( _xs , _ys ) according to the decimal part of the coordinate position (Δxt, Δyt), the arrangement of the two triangular regions in step S3, and the situation _that the sub-pixel is located in the first triangular region or the second triangular region, wherein the oblique equivalent phase ( _{xs , ys} ) is the decimal part of the coordinate value corresponding to the sub-pixel in the rotating coordinate system; Step S3 specifically includes steps S3.1 to S3.3: Step S3.1: Obtain the brightness value of each pixel in the reference pixel set; Step S3.2: Calculating a weight value corresponding to the brightness value of the pixel point according to the oblique equivalent phase (x _s , y _s ); Step S3.3: Calculate the interpolated brightness Z _s of the sub-pixel according to the weight value and the brightness value of the pixel point. 2. The direct scaling method according to claim 1, characterized in that the arrangement of the two triangular regions in step S1.3 and the situation where the sub-pixel is located in the first triangular region or the second triangular region specifically include: Case 1: the first triangular area is located at the upper right of the first pixel grid, the second triangular area is located at the lower left of the first pixel grid, and the sub-pixel is located in the second triangular area; Second situation: the first triangular area is located at the upper left of the first pixel grid, the second triangular area is located at the lower right of the first pixel grid, and the sub-pixel is located in the second triangular area; The third situation: the first triangular area is located at the upper right of the first pixel grid, the second triangular area is located at the lower left of the first pixel grid, and the sub-pixel is located in the first triangular area; Fourth situation: the first triangular area is located at the upper left of the first pixel grid, the second triangular area is located at the lower right of the first pixel grid, and the sub-pixel is located in the first triangular area. 3. The direct scaling method according to claim 2, characterized in that the coordinate reference value (x ₀ , y ₀ ) is calculated in step S1.3 by specifically calculating the coordinate reference value (x ₀ , y ₀ ) according to formula (1) and formula (2): x ₀ = x _t -2-p (1); y ₀ =y _t -2-q (2); Among them: p is 1 in the first and fourth cases, and is 0 in the second and third cases; q is 0 in the first and second cases, and is 1 in the third and fourth cases. 4. The direct scaling method according to claim 1, characterized in that: The reference pixel set includes 16 reference pixel points, and the coordinate values of the reference pixel points are represented by coordinate reference values (x ₀ , y ₀ ), which are respectively: (x ₀ +0,y ₀ +3), (x ₀ +1,y ₀ +2), (x ₀ +2,y ₀ +1), (x ₀ +3,y ₀ +0), (x ₀ +1,y ₀ +4), (x ₀ +2,y ₀ +3), (x ₀ +3,y ₀ +2), (x ₀ +4,y ₀ +1), (x ₀ + 2,y ₀ +5), (x ₀ +3,y ₀ +4), (x ₀ +4,y ₀ +3), (x ₀ +5,y ₀ +2), (x ₀ +3, y ₀ +6), (x ₀ +4, y ₀ +5), (x ₀ +5, y ₀ +4), (x ₀ +6, y ₀ +3). 5. The direct scaling method according to claim 3, characterized in that step S2 specifically comprises: The oblique equivalent phase (x _s ,y _s ) is calculated according to formula (3) and formula (4): The values of p and q are the same as those in step S1.3. 6. The direct scaling method according to claim 3, characterized in that step S3.2 specifically comprises: The weight values include an x-direction weight value and a y-direction weight value; Calculate the x-direction weight value corresponding to the reference pixel point according to xs and the filter basis function; calculate the y-direction weight value corresponding to the reference pixel point according to _ys and the filter basis function; the product of the x _- direction weight value and the corresponding y-direction weight value is the weight value of the corresponding reference pixel point; The filter basis function is formula (5): In the formula: a is a preset parameter, x is the x _- direction or y-direction position of the reference pixel point relative to the sub-pixel calculated according to xs or _ys , corresponding to the calculation of the x-direction weight value and the y-direction weight value, respectively. 7. The direct scaling method according to claim 6, characterized in that the number of the reference pixels is 16, and the pixel brightness values form a pixel brightness value matrix Z according to formula (6); Wherein, Z(x,y) represents the brightness value of the pixel corresponding to the reference pixel with coordinates (x,y), and the coordinates of the reference pixel are all represented by the coordinate reference value (x ₀ ,y ₀ ); The x-direction weight values form an x-direction row weight coefficient vector W _x ; the y-direction weight values form a y-direction row weight coefficient vector W _y ; the step S3.3 specifically calculates the brightness value Z _s of the sub-pixel by matrix multiplication according to formula (7);