WO2017088282A1

WO2017088282A1 - Display method and apparatus for adjusting picture character

Info

Publication number: WO2017088282A1
Application number: PCT/CN2016/070071
Authority: WO
Inventors: 李戎
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-11-25
Filing date: 2016-01-04
Publication date: 2017-06-01
Also published as: CN106778733A

Abstract

Provided are a display method and apparatus for adjusting a picture character. The method comprises: identifying a character region in a picture on a screen; calculating an included ang le á between a positive direction vector of the character region and a polar axis of the character region, wherein the polar axis is a coordinate axis obtained by polar coordinates extending along a positive direction of an X axis, and the polar coordinates are polar coordinates taking a specific location on the screen as a pole; and dividing a region of the picture into a plurality of angular ranges, and adjusting, according to the included angle á, the picture at locations of the plurality of angular rang es, wherein the character region is displayed in the positive direction of the adjusted picture. The solution solves the problem that it is inconvenient for a user to read the characters in the picture, thereby improving the convenience for the user to read the characters in a picture.

Description

Method and device for adjusting picture text display

Technical field

The present invention relates to the field of terminal display, and in particular to a display method and apparatus for adjusting picture characters.

Background technique

When viewing the image in full screen in the gallery, I often see some pictures with text displayed in the wrong direction. You need to rotate the screen 90° or 180° to see the text in the picture. Can it be automatically rotated on the basis of the text recognition algorithm when displaying a picture containing text, so that the user can read the text on the picture without rotating the screen or the picture?

When browsing an image with text in the gallery, the gallery cannot rotate the image according to the direction of the text, which is not conducive to the user reading the text in the image.

In view of the related art, the problem that the user reads the text in the picture is inconvenient, and there is no effective technical solution at present.

Summary of the invention

The invention provides a display method and device for adjusting picture characters, so as to at least solve the problem that the user in the related art is inconvenient to read characters in the pictures.

According to an embodiment of the present invention, a method for displaying a picture text is provided, including:

Identify the text area in the picture on the screen;

Calculating an angle α between a positive direction vector of the text region and a polar axis of the text region, wherein the polar axis is a coordinate axis obtained by extending a polar coordinate in a positive direction of the X axis, wherein the polar coordinate is The specified position of the screen is the polar coordinate of the pole;

Dividing the area of the picture into a plurality of angular ranges, and adjusting the picture according to the angle α in the plurality of angular ranges, wherein the adjusted picture displays the text area in a positive direction.

In an embodiment of the invention, the designated location is a center point location of the screen.

In an embodiment of the invention, the positive direction vector of the text area comprises at least one of the following:

When the text area has only a single character, the positive direction vector of the text area is a positive direction vector of the single character;

When there are a plurality of characters in the character region, the positive direction vector of the character region is an average value of the positive direction vectors of the plurality of characters.

In an embodiment of the invention, the positive direction vector of the text area comprises:

When there are a plurality of character regions, the positive direction vector of the character region is an average value of the positive direction vectors of the plurality of character regions.

In an embodiment of the present invention, the area of the picture is divided into a plurality of angular ranges, and adjusting the picture at the position of the plurality of angular ranges according to the angle α includes:

The region of the picture is divided into four sectors by the polar coordinates: the first sector corresponds to -π/4 to π/4, the second sector corresponds to π/4 to 3π/4, and the third sector corresponds to 3π/ 4 to 5π/4 and the fourth sector correspond to 5π/4 to 7π/4;

If the angle α is located in the second sector, the picture does not rotate;

If the angle α is located in the third sector, the picture is rotated clockwise by π/2;

If the angle α is in the fourth sector, the picture is rotated clockwise by π;

If the angle α is in the first sector, the picture is rotated counterclockwise by π/2.

According to another embodiment of the present invention, a display device for adjusting picture characters is further provided, including:

An identification module configured to identify a text area in a picture on the screen;

a calculation module configured to calculate an angle α between a positive direction vector of the text region and a polar axis of the text region, wherein the polar axis is a coordinate axis obtained by extending polar coordinates along a positive direction of the X axis, The polar coordinates are polar coordinates of a pole at a specified position of the screen;

And an adjustment module, configured to divide the area of the picture into a plurality of angular ranges, and adjust the picture according to the angle α in a position of the plurality of angular ranges, wherein the adjusted positive direction display in the picture The text area.

In an embodiment of the invention, the adjustment module comprises:

The sector adjustment unit is configured to divide the area of the picture into four sectors by using the polar coordinates: the first sector corresponds to -π/4 to π/4, and the second sector corresponds to π/4 to 3π/4, The three sectors correspond to 3π/4 to 5π/4 and the fourth sector corresponds to 5π/4 to 7π/4; and the picture is adjusted as follows:

If the angle α is located in the second sector, the picture does not rotate;

According to the present invention, the text area in the picture on the screen is recognized, and the angle α between the positive direction vector of the text area and the polar axis of the text area is calculated, wherein the polar axis is a polar coordinate extending along the positive direction of the X axis. Obtaining a coordinate axis, wherein the specified position of the screen is a polar coordinate of the pole, dividing the area of the picture into a plurality of angular ranges, and adjusting the picture according to the angle α at the position of the plurality of angular ranges, The problem that the user reads the text in the picture is inconvenient, and the convenience of the user to read the text on the picture is improved.

DRAWINGS

The drawings described herein are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

1 is a flow chart of a method for adjusting a picture text display according to an embodiment of the present invention;

2 is a structural block diagram 1 of a display device for adjusting picture characters according to an embodiment of the present invention;

3 is a structural block diagram 2 of a display device for adjusting picture characters according to an embodiment of the present invention;

4 is a flow chart of rotating a picture according to a text direction in accordance with a preferred embodiment of the present invention;

5A is a schematic diagram showing a stage of a recognized character region for rotating a picture according to a text direction according to a preferred embodiment of the present invention;

5B is a schematic diagram showing a stage of calculating a positive direction vector direction of a text region according to a text direction according to a preferred embodiment of the present invention;

5C is a schematic diagram of determining whether a rotation of a picture is required according to a text direction and performing a rotation phase according to a preferred embodiment of the present invention;

6 is a schematic diagram of an example of a single text forward direction vector calculation in accordance with a preferred embodiment of the present invention;

7 is a diagram showing an example of polar angle calculation of a text region having only a single character in accordance with a preferred embodiment of the present invention;

8 is a diagram showing an example of polar angle calculation of a plurality of characters in a text area according to a preferred embodiment of the present invention;

9 is a schematic diagram of a plurality of text regions and corresponding positive direction vectors in accordance with a preferred embodiment of the present invention;

10 is a schematic diagram of rotating a picture according to a positive direction vector of a text area, in accordance with a preferred embodiment of the present invention;

11 is a flow chart of rotating a picture according to a positive direction vector of a text area, in accordance with a preferred embodiment of the present invention;

Figure 12 is a flow diagram of an alternate embodiment of the present invention in accordance with a preferred embodiment of the present invention.

detailed description

The invention will be described in detail below with reference to the drawings in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

It is to be understood that the terms "first", "second" and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a particular order or order.

In this embodiment, a method for displaying a picture text is provided. FIG. 1 is a flowchart of a method for displaying a picture text according to an embodiment of the present invention. As shown in FIG. 1, the process includes the following steps:

Step S102, identifying a text area in the picture on the screen;

Step S104, calculating an angle α between a positive direction vector of the character region and a polar axis of the text region, wherein the polar axis is a coordinate axis obtained by extending polar coordinates along a positive direction of the X axis, wherein the polar coordinate is The specified position of the screen is the polar coordinates of the pole;

Step S106, the area of the picture is divided into a plurality of angular ranges, and the picture is adjusted according to the angle α in the plurality of angular ranges, wherein the adjusted text area displays the text area in a positive direction.

Through the above steps, the text area in the picture on the screen is identified, and the angle α between the positive direction vector of the text area and the polar axis of the text area is calculated, wherein the polar axis is a polar coordinate extending along the positive direction of the X axis. a coordinate axis obtained by using the specified position of the screen as a polar coordinate of the pole, dividing the area of the picture into a plurality of angular ranges, and adjusting the picture according to the angle α in the position of the plurality of angular ranges, wherein The adjusted text area is displayed in the positive direction of the picture, which solves the problem that the user reads the text in the picture is inconvenient, and improves the convenience of the user reading the text on the picture.

In this embodiment, the designated position is the center point position of the screen.

In this embodiment, the positive direction vector of the text area includes at least one of the following: when the text area has only a single character, the positive direction vector of the text area is a positive direction vector of the single character, and the text area has In the case of a plurality of characters, the positive direction vector of the character region is an average of the positive direction vectors of the plurality of characters.

In the present embodiment, the positive direction vector of the character region includes, when the plurality of character regions are plural, the positive direction vector of the character region is an average value of the positive direction vectors of the plurality of character regions.

In this embodiment, the area of the picture is divided into a plurality of angular ranges, and the picture is adjusted according to the angle α at the positions of the plurality of angular ranges, and the area of the picture is divided into four sectors by the polar coordinate. : the first sector corresponds to -π/4 to π/4, the second sector corresponds to π/4 to 3π/4, the third sector corresponds to 3π/4 to 5π/4, and the fourth sector corresponds to 5π/4~ 7π/4;

If the angle α is in the second sector, the picture does not rotate;

If the angle α is located in the fourth sector, the picture is rotated clockwise by π;

If the angle α is in the first sector, the picture is rotated π/2 counterclockwise.

Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, by hardware, but in many cases, the former is A better implementation. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, may be embodied in the form of a software product stored in a storage medium (such as ROM/RAM, disk, The optical disc includes a number of instructions for causing a terminal device (which may be a cell phone, a computer, a server, or a network device, etc.) to perform the methods described in various embodiments of the present invention.

In this embodiment, a display device for adjusting picture characters is also provided. The device is used to implement the above-mentioned embodiments and preferred embodiments, and the detailed description thereof has been omitted. As used below, the term "module" may implement a combination of software and/or hardware of a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware, is also possible and contemplated.

2 is a block diagram of a structure of a display device for adjusting picture characters according to an embodiment of the present invention. As shown in FIG. 2, the device includes:

The identification module 22 is configured to identify a text area in the picture on the screen;

The calculation module 24 is configured to calculate an angle α between the positive direction vector of the text region and the polar axis of the text region, wherein the polar axis is a coordinate axis obtained by extending polar coordinates along a positive direction of the X axis, the pole The coordinate is the polar coordinate of the pole with the specified position of the screen;

The adjustment module 26 is configured to divide the area of the picture into a plurality of angular ranges, and adjust the picture according to the angle α in the plurality of angular ranges, wherein the adjusted text area displays the text area in the positive direction.

Through the above steps, the recognition module 22 identifies the text area in the picture on the screen, and the calculation module 24 calculates an angle α between the positive direction vector of the text area and the polar axis of the text area, wherein the polar axis is a polar coordinate edge a coordinate axis obtained by extending the positive direction of the X-axis, wherein the polar coordinate is a polar coordinate of the pole at a specified position of the screen, and the adjustment module 26 divides the region of the image into a plurality of angular ranges, and the plurality of angular ranges are The position of the angle range adjusts the picture, wherein the adjusted text area displays the text area in the positive direction, which solves the problem that the user reads the text in the picture is inconvenient, and improves the convenience of the user reading the text on the picture.

FIG. 3 is a structural block diagram 2 of a display device for adjusting picture characters according to an embodiment of the present invention. As shown in FIG. 3, the adjustment module 26 further includes:

The sector adjustment unit 32 is configured to divide the area of the picture into four sectors by the polar coordinates: the first sector corresponds to -π/4 to π/4, and the second sector corresponds to π/4 to 3π/4, The three sectors correspond to 3π/4 to 5π/4 and the fourth sector corresponds to 5π/4 to 7π/4; and the picture is adjusted as follows:

If the angle α is in the second sector, the picture does not rotate;

It should be noted that each of the above modules may be implemented by software or hardware. For the latter, the foregoing may be implemented by, but not limited to, the foregoing modules are all located in the same processor; or, the modules are located in multiple In the processor.

The invention will now be described in detail in conjunction with the preferred embodiments and embodiments.

The image display method shown in the preferred embodiment of the present invention includes a mobile terminal display screen, an image display module, and a character recognition module. The text recognition module can also calculate the positive direction vector of the text while recognizing the text. A preferred embodiment of the present invention determines whether an image requires rotation and how to rotate based on a positive direction vector of the text, such as determining a rotation angle or the like. This is the core of the invention. The image display module of the preferred embodiment includes an image display algorithm, an image rotation algorithm, and a method of calling a text recognition module. The image rotation algorithm rotates the image 90° and 180° clockwise and counterclockwise, respectively. An image display algorithm is used to completely display the image on the screen of the smart terminal.

FIG. 4 is a flowchart of rotating a picture according to a text direction according to an embodiment of the present invention. As shown in FIG. 4, the steps include:

Step S401, identifying a text area in the picture;

Step S402, calculating an angle between the positive direction vector of the text region and the polar axis - the polar angle α;

Step S403, calculating an angle at which the picture needs to be rotated according to the size of α, and performing a rotation operation;

In step S404, a picture is displayed.

In another optional embodiment of the present invention, the processing steps of rotating the picture according to the text direction include:

Step one, identifying the text area stage, as shown in the picture in FIG. 5A;

Step 2, calculating a positive direction vector phase of the text area, as shown in the picture in FIG. 5B;

In step three, it is judged whether it is necessary to rotate and execute the rotation phase, as shown in the picture in FIG. 5C.

The positive direction vector of the text area is indicated by a dashed arrow. The text area is indicated by a dotted rectangular frame indicating that the angle between the positive direction vector of the text area and the polar axis is α.

A preferred technical embodiment of the embodiment of the present invention rotates a picture and displays it by accurately calculating the angle between the positive direction vector of the text and the polar axis of the coordinate system. The specific scheme can be divided into several parts: (1) the method of calculating the positive direction vector of a single character; (2) the method of calculating the positive direction vector of the text area; (3) the method of calculating the positive direction vector of the picture text; (4) according to the text The method of rotating the picture in the positive direction vector of the area. The four methods are detailed below.

Method 1, calculating a single text positive direction vector embodiment:

The text recognition algorithm will match each text in the text area one by one and calculate the positive direction vector corresponding to each text. Figure 6 is an exemplary diagram of a single text positive direction vector calculation. Each successfully matched text (the text in Figure 6) has a corresponding bounding box, as shown by the rectangular box in Figure 6. According to the unit, the positive direction vector of the text can be determined (arrow in Fig. 6).

FIG. 6 is a schematic diagram of a single text forward direction vector calculation according to a preferred embodiment of the present invention. As shown in FIG. 6, the arrow represents a square To the vector, the bold "middle" character represents the character to be recognized, the thin "middle" character represents the text obtained by the text recognition algorithm, and the outer rectangular box represents the border of the "matched text".

Method 2, calculating the positive direction vector of the text area.

There are two cases in which the positive direction vector of the text area is calculated: the text area has only a single text and the text area has multiple words. In the following two cases, the calculation of the positive direction vector of the text area is discussed separately.

Case 1: The text area has only a single text (as shown in Figure 8)

In this case, the positive direction vector of a single character can be regarded as the positive direction vector of the text area. The polar angle corresponding to the positive direction vector of a single text can also be regarded as the polar angle of the positive direction vector of the text area.

7 is a diagram showing an example of polar angle calculation of a text region having only a single character, as shown in FIG. 7, in accordance with a preferred embodiment of the present invention. The arrows represent the positive direction vector.

Case 2: There are multiple texts in the text area (as shown in Figure 8)

In this case, the positive direction vector of the text area is the average of all the text positive direction vectors. Its corresponding polar angle is also the average of all positive direction vector polar angles. Its calculation formula is

For example, each text in Figure 8 has a positive direction vector and corresponds to its respective polar angle. The polar angle corresponding to the positive direction vector of the text area is calculated as:

Figure 8 is a diagram showing an example of polar angle calculation of a plurality of characters in a text area, as shown in Figure 8, in accordance with a preferred embodiment of the present invention. Red arrow indicates the positive direction vector _{_{text, α 1, α 2, α}} 3, α 4 each represent a polar angle character corresponding to the positive direction of the vector.

Method 3, calculating the positive direction vector of the picture text embodiment:

There may be multiple text areas in the picture, and each text area has its own positive direction vector.

9 is a schematic diagram of a plurality of text regions and corresponding positive direction vectors in accordance with a preferred embodiment of the present invention, as shown in FIG. 9 showing an angle between a positive direction vector (indicated by an arrow) and a polar axis corresponding to two text regions. α _A and α _B . For this case, average all positive direction vectors to get an average positive direction vector, whose polar angle is also the average of the polar angles.

You can use α to calculate how many angles the picture needs to be rotated.

Method 4, rotating the picture according to the positive direction vector of the text area:

FIG. 10 is a schematic diagram of rotating a picture according to a positive direction vector of a text area according to a preferred embodiment of the present invention. As shown in FIG. 10, it is determined whether rotation is required and the angle of rotation according to the polar angle of the positive direction vector of the text area.

11 is a flow chart of rotating a picture according to a positive direction vector of a text area according to a preferred embodiment of the present invention. As shown in FIG. 11, the steps include:

Step S1101: Establish polar coordinates, with the center of the screen as the pole, and the positive direction of the X along the positive direction of the screen. The polar coordinates are fixed.

Step S1102: dividing the picture into four sectors, corresponding to -π/4 to π/4 (sector 1), π/4 to 3π/4 (sector 2), and 3π/4 to 5π/4 (fan Zone 3) and 5π/4 to 7π/4 (sector 4).

Step S1103: Determine whether rotation is required and the angle of rotation according to the polar angle of the positive direction vector of the text region. If the polar angle belongs to sector 2, it does not rotate; if it belongs to sector 3, the picture rotates clockwise by π/2; if it is located in sector 4, it rotates π clockwise; if it is located in sector 1, it rotates counterclockwise π /2.

Step S1104: Display a picture.

In addition to the above preferred technical solutions, in an alternative embodiment of the present invention, there are also the following schemes, the effect of which is slightly different from the effect of the best technical solution: for example, the rotation angle is set to a polar angle, so that the text region positive direction vector Vertical to the polar axis, that is, the text is always displayed to the user in a positive and direct manner, and the picture may be displayed obliquely. The difference from the above preferred technical solution lies in the process of rotating a picture according to the positive direction vector of the text area, and the specific steps are as follows:

FIG. 12 is a flowchart of an implementation of an alternative technical solution according to a preferred embodiment of the present invention. As shown in FIG. 12, the steps include:

Step S1201: Establish polar coordinates, with the center of the screen as the pole, and the positive direction of the X along the positive direction of the screen. The polar coordinates are fixed.

Step S1202: Calculate the polar angle of the text area.

Step S1203: Rotate the picture according to the polar angle of the positive direction vector of the text area, so that α=π/2.

Step S1204: Display a picture.

The picture display method shown in the preferred embodiment of the present invention can facilitate the user to view pictures with text without manually rotating the screen or rotating the picture in the gallery. For the designer of the gallery, the buttons of the left-handed and right-handed pictures can be transferred from the eye-catching position to the menu option, so that the image is more completely displayed to the user, which increases the user experience.

Embodiments of the present invention also provide a storage medium. Optionally, in the embodiment, the storage medium may be configured to store program code for performing the method steps of the above embodiment:

Optionally, in this embodiment, the foregoing storage medium may include, but not limited to, a USB flash drive, a Read-Only Memory (ROM), a Random Access Memory (RAM), a mobile hard disk, and a magnetic memory. A variety of media that can store program code, such as a disc or a disc.

Optionally, in this embodiment, the processor performs the method steps of the foregoing embodiments according to the stored program code in the storage medium.

For example, the specific examples in this embodiment may refer to the examples described in the foregoing embodiments and the optional embodiments, and details are not described herein again.

It will be apparent to those skilled in the art that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed across a network of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. Perform the steps shown or described Alternatively, each of them may be fabricated into individual integrated circuit modules, or a plurality of modules or steps thereof may be fabricated into a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

According to the above technical solution provided by the embodiment of the present invention, a text area in a picture on a screen is recognized, and an angle α between a positive direction vector of the text area and a polar axis of the text area is calculated, wherein the polar axis is a polar coordinate a coordinate axis extending along a positive direction of the X-axis, wherein the polar coordinate is a polar coordinate of a pole at a specified position of the screen, and the region of the image is divided into a plurality of angular ranges, and the plurality of angular ranges are according to the angle α The position of the picture is adjusted to solve the problem that the user is inconvenient to read the text in the picture, and the convenience of the user to read the text on the picture is improved.

Claims

A method for adjusting the display of picture text, including:

Identify the text area in the picture on the screen;

Calculating an angle α between a positive direction vector of the text region and a polar axis of the text region, wherein the polar axis is a coordinate axis obtained by extending a polar coordinate in a positive direction of the X axis, wherein the polar coordinate is The specified position of the screen is the polar coordinate of the pole;

Dividing the area of the picture into a plurality of angular ranges, and adjusting the picture according to the angle α in the plurality of angular ranges, wherein the adjusted picture displays the text area in a positive direction.
The method of claim 1 wherein said designated location is a center point location of said screen.
The method of claim 1 wherein the positive direction vector of the text region comprises at least one of:

When the text area has only a single character, the positive direction vector of the text area is a positive direction vector of the single character;

When there are a plurality of characters in the character region, the positive direction vector of the character region is an average value of the positive direction vectors of the plurality of characters.
The method of claim 1 wherein the positive direction vector of the text region comprises:

When there are a plurality of character regions, the positive direction vector of the character region is an average value of the positive direction vectors of the plurality of character regions.
The method according to claim 1, wherein the area of the picture is divided into a plurality of angular ranges, and adjusting the picture at positions of the plurality of angular ranges according to the angle α includes:

The region of the picture is divided into four sectors by the polar coordinates: the first sector corresponds to -π/4 to π/4, the second sector corresponds to π/4 to 3π/4, and the third sector corresponds to 3π/ 4 to 5π/4 and the fourth sector correspond to 5π/4 to 7π/4;

If the angle α is located in the second sector, the picture does not rotate;

If the angle α is located in the third sector, the picture is rotated clockwise by π/2;

If the angle α is in the fourth sector, the picture is rotated clockwise by π;

If the angle α is in the first sector, the picture is rotated counterclockwise by π/2.
A display device for adjusting picture text, comprising:

An identification module configured to identify a text area in a picture on the screen;

a calculation module configured to calculate an angle α between a positive direction vector of the text region and a polar axis of the text region, wherein the polar axis is a coordinate axis obtained by extending polar coordinates along a positive direction of the X axis, The polar coordinates are polar coordinates of a pole at a specified position of the screen;

And an adjustment module, configured to divide the area of the picture into a plurality of angular ranges, and adjust the picture according to the angle α in a position of the plurality of angular ranges, wherein the adjusted positive direction display in the picture The text area.
The apparatus of claim 6, wherein the designated location is a center point location of the screen.
The apparatus of claim 6, wherein the positive direction vector of the text region comprises at least one of:

When the text area has only a single character, the positive direction vector of the text area is a positive direction vector of the single character;

When there are a plurality of characters in the character region, the positive direction vector of the character region is an average value of the positive direction vectors of the plurality of characters.
The apparatus of claim 6 wherein the positive direction vector of the text region comprises:

When there are a plurality of character regions, the positive direction vector of the character region is an average value of the positive direction vectors of the plurality of character regions.
The apparatus of claim 6 wherein said adjustment module comprises:

The sector adjustment unit is configured to divide the area of the picture into four sectors by using the polar coordinates: the first sector corresponds to -π/4 to π/4, and the second sector corresponds to π/4 to 3π/4, The three sectors correspond to 3π/4 to 5π/4 and the fourth sector corresponds to 5π/4 to 7π/4; and the picture is adjusted as follows:

If the angle α is located in the second sector, the picture does not rotate;

If the angle α is located in the third sector, the picture is rotated clockwise by π/2;

If the angle α is in the fourth sector, the picture is rotated clockwise by π;

If the angle α is in the first sector, the picture is rotated counterclockwise by π/2.