Method, apparatus, device and medium for evaluating distortion correction results of a projection screen

Abstract

[0009] The present disclosure provides a method, apparatus, device, and storage medium for evaluating a distortion correction result of a projection screen, the method including the steps of: acquiring corner point coordinates of the projection screen, where the projection screen is a rectangle, and the corner point coordinates are coordinates corresponding to four corners of the rectangle in a rectangular coordinate system; acquiring four included angles between four sides of the projection screen and corresponding sides of an absolute rectangle, where one pair of opposing sides of the rectangle are parallel to the X-axis in the rectangular coordinate system and another pair of opposing sides are parallel to the Y-axis in the rectangular coordinate system, with the X-axis being horizontal and the Y-axis being vertical; determining values of the four included angles based on the corner point coordinates; and evaluating the correction result of the projection screen based on the values of the four included angles. [0010] The present disclosure provides a method, apparatus, device, and storage medium for evaluating a distortion correction result of a projection screen, the method including the steps of: acquiring corner point coordinates of the projection screen, where the projection screen is a rectangle, and the corner point coordinates are coordinates corresponding to four corners of the rectangle in a rectangular coordinate system; acquiring four included angles between four sides of the projection screen and corresponding sides of an absolute rectangle, where one pair of opposing sides of the rectangle are parallel to the X-axis in the rectangular coordinate system and the other pair of opposing sides are parallel to the Y-axis in the rectangular coordinate system, with the X-axis being horizontal and the Y-axis being vertical.

Description

Related Applications

[0001] This application claims priority to Chinese Patent Application No. 202210983624.4, filed on August 16, 2022, the entire contents of which are incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to the field of projection technology, and more particularly to a method, apparatus, device and medium for evaluating distortion correction results of a projection screen. [Background technology]

[0003] Portable home projectors are increasingly popular due to their easy installation and portability, and this is primarily due to the development of keystone correction technology, which eliminates the need to directly face the projector to the projection screen and allows the image to be projected essentially directly onto the screen.

[0004] In the related art, there are several keystone correction solutions that can achieve keystone correction of a projection screen, but there is no unified standard for evaluating the keystone correction results, which causes problems in the keystone correction process such as low correction efficiency and difficulty in determining correction accuracy. Summary of the Invention

[0005] Therefore, the embodiments of the present disclosure provide a method, an apparatus, a device and a medium for evaluating the distortion correction result of a projection screen, in order to solve the technical problem that it is difficult to evaluate the keystone correction result.

[0006] In a first aspect, an embodiment of the present disclosure provides a method for evaluating a distortion correction result of a projection screen, the method comprising: acquiring corner point coordinates of the projection screen, where the projection screen is a rectangle and the corner point coordinates are coordinates corresponding to four corner points of the rectangle in a rectangular coordinate system; obtaining four included angles between four sides of the projection screen and corresponding sides of an absolute rectangle, wherein one pair of opposing sides of the four sides of the absolute rectangle are parallel to an X-axis in the Cartesian coordinate system, and another pair of opposing sides are parallel to a Y-axis in the Cartesian coordinate system, the X-axis being horizontal and the Y-axis being vertical; determining values of the four included angles based on the corner point coordinates; and evaluating the correction result of the projection screen based on the values of the four included angles.

[0007] In a second aspect, an embodiment of the present disclosure further provides an apparatus for evaluating a distortion correction result of a projection screen, the apparatus comprising: a collection unit configured to acquire corner point coordinates of the projection screen, where the projection screen is a rectangle and the corner point coordinates are coordinates corresponding to four corner points of the rectangle in a rectangular coordinate system; an acquisition unit configured to acquire four included angles between four sides of the projection screen and corresponding sides of an absolute rectangle, wherein one pair of opposing sides of the four sides of the absolute rectangle are parallel to an X-axis in the Cartesian coordinate system, and another pair of opposing sides are parallel to a Y-axis in the Cartesian coordinate system, the X-axis being horizontal and the Y-axis being vertical; a determining unit configured to determine values of the four included angles based on the corner point coordinates; and an evaluation unit configured to evaluate a correction result of the projection screen based on the values of the four included angles.

[0008] In a third aspect, an embodiment of the present disclosure further provides a projection device, comprising a control unit and a projection unit, wherein the control unit controls the projection unit to execute a projection command, and evaluates a correction result of projection screen distortion by the method steps described in any one of the preceding claims.

[0009] In a fourth aspect, an embodiment of the present disclosure further provides a projection device, comprising a control unit and an evaluation device according to any one of the preceding claims, wherein the control unit controls the evaluation device to evaluate a correction result of the projection screen distortion.

[0010] In a fifth aspect, an embodiment of the present disclosure further provides an electronic device comprising a processor and a memory, the memory storing computer program instructions executable by the processor, the method steps of any one of the preceding claims being implemented when the processor executes the computer program instructions.

[0011] In a sixth aspect, an embodiment of the present disclosure further provides a non-transitory computer-readable storage medium having stored thereon computer program instructions, the computer program instructions, when called and executed by a processor, implementing the method steps of any one of the preceding claims. [Brief explanation of the drawings]

[0012] In order to more clearly describe the technical solutions in the embodiments of the present disclosure or related technologies, the accompanying drawings necessary for the description of the embodiments or related technologies will be briefly described below. Obviously, the accompanying drawings described below are some embodiments of the present disclosure, and anyone skilled in the art can obtain other drawings based on these accompanying drawings without any creative work.

[0013] [Figure 1] 1 is a schematic diagram illustrating a projection state of a projection device provided by an embodiment of the present disclosure. [Figure 2] 1 is a flowchart of a correction result evaluation method provided by an embodiment of the present disclosure. [Figure 3] 1 is a schematic diagram of a projection screen of a projection device provided by an embodiment of the present disclosure. [Figure 4] 10 is a flowchart of a correction result evaluation method provided by another embodiment of the present disclosure. [Figure 5]FIG. 2 is a schematic diagram of a quadrant structure of a projection screen provided by an embodiment of the present disclosure. [Figure 6] 1A-1C are schematic diagrams illustrating different states of a projection screen provided by an embodiment of the present disclosure. [Figure 7] FIG. 10 is a schematic diagram of coordinates of a projected image provided by another embodiment of the present disclosure. [Figure 8] 10 is a flowchart of a correction result evaluation method provided by another embodiment of the present disclosure. [Figure 9] 10 is a flowchart of a correction result evaluation method provided by another embodiment of the present disclosure. [Figure 10] 10 is a flowchart of a correction result evaluation method provided by another embodiment of the present disclosure. [Figure 11] 10 is a flowchart of a correction result evaluation method provided by another embodiment of the present disclosure. [Figure 12] 10 is a flowchart of a correction result evaluation method provided by another embodiment of the present disclosure. [Figure 13] FIG. 1 is a structural schematic diagram of a correction result evaluation device provided by an embodiment of the present disclosure; [Figure 14] 1 is a structural schematic diagram of a projection device provided by an embodiment of the present disclosure; [Figure 15] 1 is a schematic diagram of the electronic structure of an electronic device provided by an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] In order to make the objectives, technical solutions and advantages of the present disclosure clearer, the present disclosure will be described in more detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present disclosure, not all embodiments. Based on the embodiments of the present disclosure, other embodiments obtained without the creative labor of artisans are all included in the protection scope of the present disclosure.

[0015] The terms used in the embodiments of the present disclosure are used only for the purpose of describing particular embodiments and are not intended to limit the present disclosure. As used in the embodiments of the present disclosure and the appended claims, the singular forms "a," "the," and "the" are also intended to include the plural, and "plurality" generally includes at least two, unless the context clearly indicates otherwise.

[0016] It should be noted that the term "and / or" as used herein merely describes the relationship between related objects and indicates that three relationships may exist; for example, A and / or B may have three relationships: A may exist alone, A and B may exist simultaneously, and B may exist alone. Furthermore, the character " / " in this specification generally means that the related objects before and after it are in an "or" relationship.

[0017] It should be noted that the terms "comprise," "include," or any other variation thereof are intended to cover a non-exclusive inclusion, such that a product or device comprising a set of elements includes not only those elements but also other elements not expressly listed or inherent in such product or device. Unless further limited, an element defined by the phrase "comprises" does not exclude the presence of other identical elements in a product or device that includes said element.

[0018] As shown in FIG. 1, a projector projects an image onto a projection surface, such as a wall or curtain. Then, for user viewing, a non-absolute rectangular projection is adjusted to an absolute rectangle using a keystone correction method. The three-dimensional rectangular coordinate system shown in FIG. 1 is defined as follows: the projector is the origin, the projection direction of the projector is the Z-axis, the horizontal direction to the right of the projector is the X-axis, and the downward direction perpendicular to the XZ plane is the Y-axis. The absolute rectangle means that one pair of opposing sides of the rectangle is parallel to the X-axis of the Cartesian coordinate system, and the other pair of opposing sides is parallel to the Y-axis of the Cartesian coordinate system, with the X-axis being horizontal and the Y-axis being vertical. The main function of keystone correction is to correct trapezoidal distortion of the screen that occurs during projector projection. When using a projector, users typically do not need to spend a long time adjusting the projection angle of the projector. They simply position the projector and use the projector's own keystone correction function to correct the trapezoidal distortion, greatly enhancing user convenience.

[0019] Conventional keystone correction technology is relatively complicated, requiring many steps for users to adjust the projection image to an absolute rectangle. Related technologies do not yet have a method for completely and easily evaluating the keystone correction effect. Most related technologies evaluate the rectangularity, for example, by evaluating the rectangularity through the four inner corners of the rectangle. However, this technology cannot handle a projected image that only has a roll angle in the horizontal plane with the projector, that is, the result of keystone correction is a tilted rectangle. Although such a keystone corrected image meets the rectangularity evaluation standard, it cannot achieve the goal of complete evaluation of keystone correction. This is because the purpose of keystone correction is to allow users to view images properly by adjusting the projector. This is because it produces a horizontal rectangular projection.

[0020] Related art technologies can only determine whether a screen is rectangular through a captured image, and essentially determine whether a projected image is rectangular through the four sides or four vertices of the screen. This determination process cannot identify whether the projected screen is a horizontal rectangle. Furthermore, this determination process cannot identify the installation angle of the projector from which the rectangle is tilted, so it cannot guide a keystone correction algorithm to quickly correct the screen.

[0021] To solve the above problem, an embodiment of the present disclosure provides a method for fully evaluating the distortion correction result of a projection screen, which first obtains the corner point coordinates of the projection screen, where the projection screen is a rectangle and the corner point coordinates are the corner point coordinates of the rectangle in a Cartesian coordinate system, then obtains the four included angles between the four sides of the projection screen and the corresponding sides of an absolute rectangle, and finally evaluates the correction result of the projection screen based on the four included angles.

[0022] The method for evaluating distortion correction results of a projection screen provided by the embodiments of the present disclosure provides a more complete and concise keystone correction evaluation standard, which can evaluate rectangularity and horizontality simultaneously based on the four included angles between the four sides of the projection screen and the corresponding sides of the absolute rectangle, improving evaluation efficiency and accuracy. The standard is simple to calculate and allows for more complete evaluation and analysis of keystone correction results. The embodiments of the present disclosure establish qualitative and quantitative relationships between evaluation parameters and keystone correction correction parameters, which can help quickly identify problems in keystone correction. The embodiments of the present disclosure also provide evaluation standard parameters for keystone correction algorithms, allowing keystone correction results to be directly evaluated using only a single evaluation standard parameter, which is very convenient for developing and optimizing keystone correction algorithms. The embodiments of the present disclosure do not require too many evaluation parameters, making the evaluation process simpler and the evaluation results easier to read.

[0023] As shown in FIG. 2 , an embodiment of the present disclosure provides a method for evaluating a distortion correction result of a projection screen, which includes the following method steps:

[0024] Step S201: Obtaining corner point coordinates of the projection screen, where the projection screen is a rectangle, and the corner point coordinates are coordinates corresponding to the four corner points of the rectangle in a rectangular coordinate system.

[0025] Step S203: Obtain four included angles between the four sides of the projection screen and the corresponding sides of an absolute rectangle, where the absolute rectangle is a rectangle in which one pair of opposing sides among the four sides is parallel to the X-axis of a Cartesian coordinate system, and another pair of opposing sides is parallel to the Y-axis of the Cartesian coordinate system, where the X-axis is horizontal and the Y-axis is vertical.

[0026] Step S205: Determine the values of the four included angles based on the corner point coordinates.

[0027] Step S207: Evaluate the correction result of the projection screen based on the values of the four included angles.

[0028] As shown in Figure 3, a solid dot represents a projector, and its projection optical axis direction is the Z axis direction. The X axis of the projector is defined as being horizontal and pointing to the right, and the Y axis is defined as being vertical and pointing downward, perpendicular to X and Z. Here, the origin O of the coordinate system is defined at the center of the optical mechanical hardware of the projector, and the projector is simplified as the origin O. To make the following explanation easier to understand, the left-hand direction when facing the projection surface is defined as left, the right-hand direction as right, the direction of gravity as down, and the direction opposite to the direction of gravity as up. Usually, keystone correction is performed by adjusting the swing angle (Yaw) of the projected image. ), pitch angle, and roll angle must be corrected. Here, pitch angle is the angle between the projector's optical axis and the projection plane in the Y-O-Z plane, swing angle is the angle between the projector's optical axis and the projection plane in the X-O-Z plane, and roll angle is the angle between the projector's X-axis and absolute horizontal plane, which is the horizontal plane perpendicular to the direction of gravity. Typically, the pitch angle and swing angle that the projector needs to correct can be calculated by sensing the projection plane, and the projector's roll angle can be calculated using an accelerometer or similar device. Since the purpose of keystone correction is to correct these three angles, the effects of these three angles must be considered simultaneously when evaluating the effectiveness of keystone correction.

[0029] In step S201, the projector projects an image onto a projection surface, such as a wall or a curtain, and captures the projection image using a camera module other than the projection function of the projector, such as a camera module integrated into the projector case or a non-integrated independent camera module, and obtains corner point coordinates of the projection image, where the projection image is a rectangle formed by projecting it onto the projection surface, and the corner point coordinates are the corner point coordinates of the rectangle in a rectangular coordinate system.

[0030] The step of obtaining the corner point coordinates of the projection screen includes the following sub-steps, as shown in FIG. 4: Step S2011: Any projection screen is randomly collected.

[0031] The projection screen is captured by a capture module other than the projection function of the projector, for example, a capture module integrated into the projector case or a non-integrated independent capture module, and the screen is captured to obtain the coordinate values of the corner points required for constructing the evaluation method described below. Optionally, the deviation angle of the rectangle relative to the corresponding side of the absolute rectangle can be obtained through the captured screen, and thus the subsequent evaluation parameters can be obtained. Here, the absolute rectangle refers to a rectangle whose top and bottom sides are horizontal (parallel to the X-axis) and whose left and right sides are vertical (parallel to the Y-axis). The absolute rectangle is the ideal target state of keystone correction, i.e., the standard shape.

[0032] Step S2013: Determine the positions of the four corner points P1, P2, P3, and P4 of the projection screen in the rectangular coordinate system, obtain the coordinates of the four corner points P1, P2, P3, and P4, and set P1(P1 X , P1 Y ), P2(P2 X , P2 Y ), P3(P3 X , P3 Y ), P4(P4 X , P4 Y )

[0033] An XY Cartesian coordinate system is constructed on the projection surface, with the horizontal direction toward the right being the positive X-axis direction and the vertical direction toward the top being the positive Y-axis direction. As shown in FIG. 5, the projection surface coordinate system can be coordinate-converted to a three-dimensional Cartesian coordinate system with the projector constructed as shown in FIG. 1 as its origin. Here, the coordinate origin O of the Cartesian coordinate system in the Cartesian coordinate system may be located at any position on the projection screen, for example, at any corner point of a rectangular projection screen, or at the center (such as the center) of the rectangular projection screen, or at any side of the rectangular projection screen.

[0034] The following embodiment shows a calculation method when the coordinate origin is in the center of the rectangular projection screen, and other embodiments are not illustrated.

[0035] Step S2013-1: Construct four quadrants of the projection screen based on a Cartesian coordinate system, which are the first quadrant, the second quadrant, the third quadrant and the fourth quadrant, where the four corner points of the rectangle are located in the four quadrants respectively.

[0036] As shown in FIG. 5, four quadrants of the projection screen are constructed based on a rectangular coordinate system, and the X-axis positive direction and the Y-axis positive direction are defined as the first quadrant, the X-axis negative direction and the Y-axis positive direction are defined as the second quadrant, the X-axis negative direction and the Y-axis negative direction are defined as the third quadrant, and the X-axis positive direction and the Y-axis negative direction are defined as the fourth quadrant. The four corner points of the shape (P1, P2, P3, P4) are located in the four quadrants respectively.

[0037] Step S2013-2: The four corner points located in the second, first, fourth and third quadrants are designated as P1, P2, P3 and P4, respectively.

[0038] Step S2013-3: The coordinates P1 (P1 X , P1 Y ), P2(P2 X , P2 Y ), P3(P3 X , P3 Y ), P4(P4 X , P4 Y ) to get the

[0039] The construction of the above four quadrants and four corner point positions facilitates the acquisition of the coordinate parameters of the four corner points, and the calculation and acquisition of the parameters of the four included angles in a later step accurately establishes the qualitative and quantitative relationship between the evaluation parameters and the trapezoid correction parameters, further assists in quickly identifying problems existing in the trapezoid correction, and at the same time facilitates the provision of evaluation parameters for the trapezoid correction algorithm.

[0040] Theoretically, the rectangle after trapezoidal correction should be an absolute rectangle with the top and bottom edges parallel to the absolute horizontal plane, as shown in part (A) of Figure 6. However, due to the accumulation of various errors, an irregular rectangle is initially obtained during the projection process, as shown in part (B) of Figure 6. To evaluate the rectangle correction effect, after fully considering the effects of pitch, yaw, and roll on the correction result, four parameters related to pitch angle, yaw angle, and roll angle are constructed, which respectively represent the angles between the four edges of the corrected rectangle and the absolute horizontal rectangle edge, allowing for a simple characterization of the rectangle correction evaluation effect.

[0041] JPEG2025526892000002.jpg244154

[0042] In step S207, the correction result may be evaluated in several ways, for example: In some embodiments, evaluating the correction result of the projection screen based on the four included angles includes the following method steps, as shown in FIG. 8 : Step S2071: If the values of the four included angles are all 0 degrees, the correction is successful; Step S2072: If the values of the four included angles are not all 0 degrees, the correction fails.

[0043] JPEG2025526892000003.jpg59148

[0044] Here, if the values of the four included angles are not all 0 degrees, or one, two, or three are not 0 degrees, or all are not 0 degrees, then the correction fails. Note that here, the value of the four included angles not all being 0 degrees may include the value of the four included angles being substantially not all being 0 degrees, and if at least one of the values of the four included angles is clearly not 0 degrees, then it indicates that the rectangle is distorted and needs to be corrected again.

[0045] In some embodiments, the four included angle values being substantially all 0 degrees may be understood as a predetermined range of values near 0, for example, a value within the range (-0.01, +0.01) being understood to be substantially equal to 0, and otherwise not being substantially equal to 0.

[0046] In some embodiments, as shown in FIG. 6 , if the values of the four included angles are not all zero, the correction fails, including the following embodiments: JPEG2025526892000004.jpg89148

[0047] JPEG2025526892000005.jpg42155

[0048] The evaluation method of the embodiments of the present disclosure can quickly identify the main cause of error in the keystone correction algorithm by analyzing the magnitude and / or positive / negative of the deviation of each angle in the keystone correction, and can quickly identify problems in the keystone correction algorithm by calculating the magnitude and / or direction of the error in the keystone correction correction parameters (Pitch, Yaw, Roll), thereby clarifying the correction direction for image distortion. Because this evaluation method does not use too many evaluation parameters, the evaluation process is simpler, the evaluation results are easier to read, and it is easier to compare the advantages and disadvantages of various distortion correction methods, making it possible to clearly identify the direction for improvement of the distortion correction method.

[0049] JPEG2025526892000006.jpg39151

[0050] JPEG2025526892000007.jpg23151

[0051] JPEG2025526892000008.jpg12151

[0052] In step S2074, some examples are as follows: the larger the arithmetic mean value, the larger the calibration error of the roll angle; and / or, if the arithmetic mean value is greater than 0, there is a positive deviation in the roll angle; and / or, if the arithmetic mean value is less than 0, there is a negative deviation in the roll angle.

[0053] JPEG2025526892000009.jpg76151

[0054] JPEG2025526892000010.jpg38154

[0055] JPEG2025526892000011.jpg27154

[0056] JPEG2025526892000012.jpg70154

[0057] JPEG2025526892000013.jpg39149

[0058] JPEG2025526892000014.jpg29149

[0059] JPEG2025526892000015.jpg78149

[0060] JPEG2025526892000016.jpg40149

[0061] JPEG2025526892000017.jpg23149

[0062] JPEG2025526892000018.jpg47152

[0063] JPEG2025526892000019.jpg55123

[0064] Here, PitchErr indicates an error factor of the pitch angle, YawErr indicates an error factor of the yaw angle, and RollErr indicates an error factor of the roll angle, and each error factor as a whole reflects the error state of the current projection screen.

[0065] In some embodiments, in step S20710, evaluating the correction result of the projection screen based on the evaluation standard includes: calculating an E value corresponding to the current projection screen based on the evaluation standard, where the smaller the calculated E value, the closer the rectangle of the projection screen is to the absolute rectangle, and the larger the calculated E value, the more the rectangle of the projection screen deviates from the absolute rectangle. Therefore, when evaluating the correction state, it is desirable to minimize the E value of the projection screen obtained from the current correction result calculated according to the evaluation standard; for example, if E is 0, the corrected projection screen is an absolute rectangle.

[0066] This embodiment provides a more complete and concise keystone correction evaluation standard E, which can evaluate not only rectangularity but also horizontality, i.e., determine whether the correction result is a rectangle and at the same time determine whether the correction result is a horizontal absolute rectangle, thereby solving the problem of unilaterally evaluating keystone correction in related evaluation methods. This embodiment establishes a qualitative and quantitative relationship between the evaluation parameters and the keystone correction correction parameters, which can further help quickly identify problems in keystone correction. This embodiment provides an evaluation standard E for keystone correction algorithms, which can directly evaluate the advantages and disadvantages of keystone correction algorithms using only a single parameter (evaluation standard E), greatly facilitating the development and optimization of keystone correction algorithms, making the evaluation process simpler and the evaluation results easier to read.

[0067] The embodiments of the present disclosure further provide an apparatus for evaluating a distortion correction result of a projection screen, which can be used to implement the evaluation method described in the above embodiments, and the same features have the same technical effects, which will not be repeated here. Specifically, as shown in FIG. 13 , the evaluation apparatus includes the following units: A collection unit 1201 is configured to acquire corner point coordinates of the projection screen, where: the projection screen is a rectangle, and the corner point coordinates are coordinates corresponding to four corner points of the rectangle in a rectangular coordinate system; an acquiring unit 1203 configured to acquire four included angles between four sides of the projection screen and corresponding sides of an absolute rectangle, where the absolute rectangle means that one pair of opposing sides of the four sides of the rectangle are parallel to an X-axis in the Cartesian coordinate system, and another pair of opposing sides are parallel to a Y-axis in the Cartesian coordinate system, the X-axis being horizontal, and the Y-axis being vertical; a determining unit 1205 configured to determine values of the four included angles according to the corner point coordinates; The evaluation unit 1207 is configured to evaluate the correction result of the projection screen according to the values of the four included angles.

[0068] JPEG2025526892000020.jpg62152

[0069] JPEG2025526892000021.jpg73152

[0070] JPEG2025526892000022.jpg23152

[0071] In some embodiments, the evaluation unit 1207 is further configured such that: the larger the arithmetic mean value, the larger the calibration error of the roll angle; and / or if the arithmetic mean value is greater than 0, there is a positive deviation in the roll angle; and / or if the arithmetic mean value is less than 0, there is a negative deviation in the roll angle.

[0072] JPEG2025526892000023.jpg27152

[0073] JPEG2025526892000024.jpg30157

[0074] JPEG2025526892000025.jpg25147

[0075] JPEG2025526892000026.jpg29147

[0076] JPEG2025526892000027.jpg39147

[0077] JPEG2025526892000028.jpg25147

[0078] JPEG2025526892000029.jpg51147

[0079] In some embodiments, the evaluation unit 1207 is further configured such that the smaller the evaluation standard E, the closer the projection screen rectangle is to the absolute rectangle, and the larger the evaluation standard E, the more the projection screen rectangle deviates from the absolute rectangle.

[0080] In some embodiments, the collection unit 1201 further comprises: randomly collecting an arbitrary projection screen, determining the positions of four corner points P1, P2, P3, and P4 of the projection screen in a Cartesian coordinate system, obtaining the coordinates of the four corner points P1, P2, P3, and P4, and calculating P1(P1 X , P1 Y ), P2(P2 X , P2 Y ), P3(P3 X , P3 Y ), P4(P4 X , P4 Y ) is configured.

[0081] JPEG2025526892000030.jpg80148

[0082] An embodiment of the present disclosure further provides a projection device, which includes a control unit 1301 and a projection unit 1303, as shown in FIG. 14, wherein the control unit 1301 controls the projection unit 1303 to execute a projection command, and evaluates the correction result of the projection screen distortion by the method steps described in any one of the above.

[0083] An embodiment of the present disclosure further provides a projection device, comprising: a control unit and an evaluation device according to any one of the above aspects, wherein the control unit controls the evaluation device to evaluate a correction result of the projection screen distortion.

[0084] An embodiment of the present disclosure further provides an electronic device, comprising a processor and a memory, the memory storing computer program instructions executable by the processor, the processor When the computer executes the computer program instructions, the method steps of any one of the preceding claims are performed.

[0085] An embodiment of the present disclosure further provides a non-transitory computer-readable storage medium having stored thereon computer program instructions that, when called and executed by a processor, implement the method steps of any one of the preceding claims.

[0086] 15, the electronic device includes a processing unit (e.g., a central processor, a graphics processor, etc.) 1401 that can perform various appropriate operations and processes according to programs stored in a read-only memory (ROM) 1402 or programs loaded from a storage device 1408 into a random access memory (RAM) 1403. The RAM 1403 further stores various programs and data necessary for the operation of the projection device. The processing unit 1401, the ROM 1402, and the RAM 1403 are connected to each other via a bus 1404. An input / output (I / O) interface 1405 is also connected to the bus 1404.

[0087] Typically, input devices 1406 such as a touchscreen, touchpad, camera, microphone, accelerometer, gyroscope, etc., output devices 1407 such as a liquid crystal display (LCD), speaker, vibrator, etc., storage device 1408 such as a hard disk, and communication device 1409 may be connected to the I / O interface 1405. The communication device 1409 allows the electronic device to communicate and exchange data with other devices wirelessly or via a wired connection. While FIG. 15 illustrates an electronic device with various devices, it should be understood that it is not necessary to implement or embody all of the devices shown. More or fewer devices may alternatively be implemented or embody.

[0088] The flowcharts and block diagrams in the accompanying drawings illustrate possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowcharts or block diagrams may represent a module, program segment, or portion of code, which includes one or more executable instructions for implementing specified logical functions. It should be noted that in some alternative implementations, the functions shown in the blocks may occur in a different order than that shown in the accompanying drawings. For example, two blocks shown in succession may actually be executed substantially in parallel, or they may be executed in reverse order depending on the related functionality. Furthermore, each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated system based on a hard disk for performing the specified functions or operations, or by a combination of a dedicated hard disk and computer instructions.

[0089] Finally, it should be noted that the embodiments in this specification will be described step by step, each embodiment will focus on the differences from other embodiments, and the same or similar parts between the embodiments may be referred to. The systems or devices disclosed in the embodiments will be briefly described because they correspond to the methods disclosed in the embodiments, and the relevant parts may be referred to the description of the method parts.

[0090] The above examples are used to explain the technical solutions of the present disclosure, but are not intended to limit them. The present disclosure has been described in detail with reference to the above examples. However, those skilled in the art may still modify the technical solutions described in each of the above examples or substitute some of the technical features with equivalents, and it should be understood that these modifications and substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each of the embodiments of the present disclosure.

Claims

1. A method for evaluating a distortion correction result of a projection screen, comprising: acquiring corner point coordinates of the projection screen, the projection screen being a rectangle, and the corner point coordinates being coordinates corresponding to four corner points of the rectangle in a rectangular coordinate system; obtaining four included angles between four sides of the projection screen and corresponding sides of an absolute rectangle, and determining that one pair of opposing sides of the four sides of the absolute rectangle are parallel to an X-axis in the Cartesian coordinate system and another pair of opposing sides are parallel to a Y-axis in the Cartesian coordinate system, the X-axis being horizontal and the Y-axis being vertical; determining values of the four included angles based on the corner point coordinates; and evaluating the correction result of the projection screen based on the values of the four included angles.

2.

3. The step of evaluating the correction result of the projection screen based on the values of the four included angles includes: If the values of the four included angles are all 0 degrees, the correction is successful; 2. The evaluation method according to claim 1, further comprising: failing the correction if the values of the four included angles are not all 0 degrees.

4.

5. The step of evaluating the correction result of the projection screen based on the values of the four included angles includes: calculating an arithmetic mean value of the four included angles; Evaluating a calibration error and / or a direction of the roll angle of the projection screen based on the arithmetic mean value.

2. The evaluation method of claim 1, further comprising: evaluating the

6. Evaluating the calibration error and / or direction of the roll angle of the projection screen based on the arithmetic average value includes: the larger the arithmetic mean value, the larger the calibration error of the roll angle; and / or If the arithmetic mean value is greater than 0, there is a positive deviation in the roll angle, and / or The evaluation method according to claim 5 , wherein the arithmetic mean value being smaller than 0 indicates that the roll angle has a deviation in a negative direction.

7.

8.

9.

10.

11.

12.

13.

14. Evaluating the correction result of the projection screen based on the evaluation standard 14. The evaluation method of claim 13, further comprising: calculating an E value corresponding to the current projection screen based on the evaluation standard; and, the smaller the calculated E value, the closer the rectangle of the projection screen is to the absolute rectangle; and, the larger the calculated E value, the more the rectangle of the projection screen deviates from the absolute rectangle.

15. The step of acquiring corner point coordinates of the projection screen includes: Randomly collecting any projection screens; The positions of four corner points P1, P2, P3, and P4 of the projection screen in a rectangular coordinate system are determined, and the coordinates of the four corner points P1, P2, P3, and P4 are obtained. Ｘ , P1 Ｙ ), P2 (P2 Ｘ , P2 Ｙ ), P3 (P3 Ｘ , P3 Ｙ ), P4 (P4 Ｘ , P4 Ｙ 2. The evaluation method according to claim 1, further comprising:

16. Determining the positions of four corner points P1, P2, P3, and P4 of the projection screen in the rectangular coordinate system and obtaining the coordinates of the four corner points P1, P2, P3, and P4 includes: Four quadrants of the projection screen are constructed based on a rectangular coordinate system, and are designated as a first quadrant, a second quadrant, a third quadrant, and a fourth quadrant, and the four corner points of the rectangle are located in the four quadrants, respectively. And, Four corner points located in the second quadrant, the first quadrant, the fourth quadrant and the third quadrant are designated as P1, P2, P3 and P4, respectively; and obtaining the coordinates of the four corner points P1, P2, P3, and P4.

17.

18. An apparatus for evaluating a distortion correction result of a projection screen, comprising: a collection unit configured to acquire corner point coordinates of the projection screen, the projection screen being a rectangle, and the corner point coordinates being coordinates corresponding to four corner points of the rectangle in a rectangular coordinate system; an acquisition unit configured to acquire four included angles between four sides of the projection screen and corresponding sides of an absolute rectangle, wherein one pair of opposing sides of the four sides of the absolute rectangle are parallel to an X-axis in the Cartesian coordinate system and another pair of opposing sides are parallel to a Y-axis in the Cartesian coordinate system, the X-axis being horizontal and the Y-axis being vertical; a determining unit configured to determine values of the four included angles based on the corner point coordinates; an evaluation unit configured to evaluate the correction result of the projection screen based on the values of the four included angles.

19.

20. The evaluation unit further comprises: If the values of the four included angles are all 0 degrees, the correction is successful; 19. The evaluation device according to claim 18, wherein the device is configured to fail correction if the values of the four included angles are not all 0 degrees.

21.

22. The evaluation unit further comprises: Calculating the arithmetic mean value of the four included angles; 19. The evaluation device according to claim 18, configured to evaluate a calibration error and / or a direction of the roll angle of the projection screen based on the arithmetic mean value.

23. The evaluation unit further comprises: the larger the arithmetic mean value, the larger the calibration error of the roll angle; and / or If the arithmetic mean value is greater than 0, there is a positive deviation in the roll angle, and / or 23. The evaluation device according to claim 22, wherein the evaluation device is configured such that if the arithmetic mean value is smaller than 0, the roll angle has a deviation in a negative direction.

24.

25.

26.

27.

28.

29.

30.

31. The evaluation unit further comprises: Based on the evaluation standard, an E value corresponding to the currently projected screen is calculated, and if the calculated E value is small, 31. The evaluation device according to claim 30, wherein the smaller the calculated E value, the closer the rectangle of the projection screen is to the absolute rectangle, and the larger the calculated E value, the more the rectangle of the projection screen deviates from the absolute rectangle.

32. The collection unit further comprises: Randomly collect any projection screens, The positions of four corner points P1, P2, P3, and P4 of the projection screen in a rectangular coordinate system are determined, and the coordinates of the four corner points P1, P2, P3, and P4 are respectively defined as P1 (P1 Ｘ , P1 Ｙ ), P2 (P2 Ｘ , P2 Ｙ ), P3 (P3 Ｘ , P3 Ｙ ), P4 (P4 Ｘ , P4 Ｙ 20. The evaluation device according to claim 18, wherein the evaluation device is configured to acquire the information as:

33. The collection unit further comprises: The four quadrants of the projection screen based on a Cartesian coordinate system are constructed as a first quadrant, a second quadrant, a third quadrant, and a fourth quadrant, and the four corner points of the rectangle are located in the four quadrants, respectively; The four corner points located in the second quadrant, the first quadrant, the fourth quadrant, and the third quadrant are designated as P1, P2, P3, and P4, respectively.

33. The evaluation device according to claim 32, configured to obtain the coordinates of the four corner points P1, P2, P3, P4.

34.

35. A projection device comprising a control unit and a projection unit, wherein the control unit controls the projection unit to execute a projection command, and the projection device evaluates a correction result of a projection screen distortion by the method steps of any one of claims 1 to 17.

36. A projection device comprising a control unit and the evaluation device according to any one of claims 18 to 34, wherein the control unit controls the evaluation device to evaluate a correction result of distortion of a projection screen.

37. 18. An electronic device comprising a processor and a memory, wherein the memory stores computer program instructions executable by the processor, the computer program instructions, when executed by the processor, implementing the method steps of any one of claims 1 to 17.

38. A non-transitory computer-readable storage medium having stored thereon computer program instructions which, when called and executed by a processor, implement the method steps of any one of claims 1 to 17.

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