Electronic device and control method thereof

Abstract

An electronic device is disclosed. The electronic device includes: an image projection unit; a memory storing one or more instructions; and one or more processors including processing circuitry in operative connection with the image projection unit and the memory. The one or more processors individually and / or collectively execute one or more instructions to: project a test image to a screen to perform keystone correction; identifying screen reference coordinates corresponding to each of a plurality of pixels included in the test image based on keystone correction; identifying a screen reference area corresponding to each of the plurality of pixels based on the identified screen reference coordinates; identifying a reference pixel from among the plurality of pixels based on a screen reference area corresponding to each of the plurality of pixels; and identifying brightness correction information corresponding to each of the plurality of pixels based on a screen reference area of the identified reference pixel and a screen reference area of each of the plurality of pixels.

Description

Technical Field

[0001] This disclosure relates to an electronic device and a method for controlling the same, and, for example, to an electronic device and a method for controlling a projected image. Background Technology

[0002] With the recent development of electronic and optical technologies, various projectors are being widely used. A projector is an electronic device that projects light onto a screen (or projection plane) to form an image on the screen.

[0003] When projecting an image using a projector, if the projector is correctly positioned on a flat surface with its direction towards the screen, a rectangular image will be displayed on the screen. However, if this is not the case, vertical or horizontal distortion may occur, or the image may be displayed as rotated. This distortion is known as the trapezoidal effect.

[0004] Therefore, the projector projects an image that has undergone keystone correction onto the screen. However, this can lead to brightness imbalances. Summary of the Invention [Technical Solution]

[0005] According to an example embodiment, an electronic device includes: an image projector; a memory storing one or more instructions; and at least one processor including processing circuitry operatively connected to the image projector and the memory, wherein the at least one processor is individually and / or collectively configured to execute one or more instructions and is configured to: perform keystone correction by projecting a test image onto a screen; based on the keystone correction, identify screen reference coordinates corresponding to each of a plurality of pixels included in the test image; identify screen reference areas corresponding to each of the plurality of pixels based on the identified screen reference coordinates; identify a reference pixel from the plurality of pixels based on the screen reference areas corresponding to each of the plurality of pixels; and identify brightness correction information corresponding to each of the plurality of pixels based on the screen reference areas of the identified reference pixels and the screen reference areas of each of the plurality of pixels.

[0006] According to an example embodiment, at least one processor may be configured individually and / or collectively to identify the value obtained by dividing the screen reference area of ​​each of the plurality of pixels by the screen reference area of ​​a reference pixel as brightness correction information corresponding to each of the plurality of pixels.

[0007] According to an example embodiment, at least one processor may be configured individually and / or collectively to identify the pixel corresponding to the largest area among the screen reference areas corresponding to each of the plurality of pixels as a reference pixel.

[0008] According to an example embodiment, the multiple screen reference coordinates corresponding to each of the multiple pixels may include: screen reference coordinates corresponding to the four vertices of each of the multiple pixels in the test image. At least one processor may be configured individually and / or collectively to calculate the screen area of ​​each of the multiple pixels based on the screen-based four vertex coordinates of each of the multiple pixels.

[0009] According to an example embodiment, at least one processor may be configured individually and / or collectively to: identify an overlapping region of a first test image projected onto a screen according to keystone correction and a second test image projected onto a screen from an external projector device; identify the overlapping region identified on the screen as a plurality of virtual pixel regions; identify projector reference coordinates corresponding to each of the plurality of virtual pixel regions; identify screen reference coordinates corresponding to the projector reference coordinates; acquire third brightness information corresponding to each of the plurality of virtual pixel regions based on first brightness information corresponding to the identified screen reference coordinates and second brightness information corresponding to the external projector device; and identify first brightness correction information corresponding to each of the plurality of pixels included in the first test image based on the first brightness information and the third brightness information.

[0010] According to an example embodiment, at least one processor may be configured individually and / or collectively to obtain third brightness information by adding first brightness information of a first pixel corresponding to the identified screen reference coordinates and second brightness information of a second pixel corresponding to the screen reference coordinates identified by an external projector device.

[0011] According to an example embodiment, at least one processor may be configured individually and / or collectively to: identify a first pixel region with the lowest brightness from among a plurality of virtual pixel regions based on third brightness information; identify a brightness compensation value corresponding to each of the plurality of virtual pixel regions based on fourth brightness information corresponding to the first pixel region and first brightness information of each of the plurality of virtual pixel regions; and identify first brightness correction information corresponding to each of the plurality of pixels included in the first test image based on the identified brightness compensation value.

[0012] According to the example embodiment, the overlapping area of ​​the first test image and the second test image is the largest quadrilateral region in the overlapping area of ​​the first test image and the second test image, identified based on the aspect ratio of the first test image and the aspect ratio of the second test image.

[0013] According to the example embodiment, a communication interface may also be included, which includes communication circuitry, and at least one processor may be configured individually and / or collectively to: receive second brightness information from an external projector device via the communication interface; acquire second brightness correction information corresponding to each of a plurality of pixels included in the second test image based on the second brightness information and the third brightness information; and send the acquired second brightness correction information to the external projector device via the communication interface.

[0014] According to an example embodiment, the test image may include multiple markers, and at least one processor may be configured individually and / or collectively to: acquire third information indicating the vertex region position of the test image in the captured image based on first information indicating the position of the multiple markers in the test image and second information indicating the position of the multiple markers in the captured image obtained from an external device capturing the screen; correct the third information based on orientation information of the external device; and perform trapezoidal correction based on the corrected third information.

[0015] According to an example embodiment, a method for controlling an electronic device includes: performing keystone correction by projecting a test image onto a screen; identifying screen reference coordinates corresponding to each of a plurality of pixels included in the test image based on the keystone correction; identifying screen reference areas corresponding to each of the plurality of pixels based on the identified screen reference coordinates; identifying a reference pixel from the plurality of pixels based on the screen reference areas corresponding to each of the plurality of pixels; and identifying brightness correction information corresponding to each of the plurality of pixels based on the screen reference areas of the identified reference pixels and the screen reference areas of each of the plurality of pixels.

[0016] According to an example embodiment, a non-transitory computer-readable recording medium storing computer instructions, wherein when executed individually and / or jointly by at least one processor of an electronic device, the computer instructions cause the electronic device to perform operations including the following steps: performing keystone correction by projecting a test image onto a screen; identifying screen reference coordinates corresponding to each of a plurality of pixels included in the test image based on the keystone correction; identifying screen reference areas corresponding to each of the plurality of pixels based on the identified screen reference coordinates; identifying a reference pixel from the plurality of pixels based on the screen reference areas corresponding to each of the plurality of pixels; and identifying brightness correction information corresponding to each of the plurality of pixels based on the screen reference areas of the identified reference pixels and the screen reference areas of each of the plurality of pixels. Attached Figure Description

[0017] The above and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0018] Figure 1a This is a diagram illustrating an example trapezoidal correction method and the concept of a coordinate system used to help understand the example trapezoidal correction method;

[0019] Figure 1b This is a diagram illustrating an example trapezoidal correction method and the concept of a coordinate system used to help understand the example trapezoidal correction method;

[0020] Figure 2 This is a block diagram illustrating example configurations of a projector according to various embodiments;

[0021] Figure 3 This is a flowchart illustrating example methods for controlling electronic devices according to various embodiments;

[0022] Figure 4a and Figure 4b This is a diagram illustrating coordinate information according to various embodiments;

[0023] Figure 5 This is a diagram illustrating third coordinate information according to various embodiments;

[0024] Figure 6a This is a diagram illustrating example methods for acquiring roll and pitch information according to various embodiments;

[0025] Figure 6b This is a diagram illustrating example methods for acquiring roll and pitch information according to various embodiments;

[0026] Figure 7 This is a diagram illustrating example methods for obtaining yaw information according to various embodiments;

[0027] Figure 8a This is a diagram illustrating example methods for obtaining the distance between a user terminal and a screen according to various embodiments;

[0028] Figure 8b This is a diagram illustrating example methods for obtaining the distance between a user terminal and a screen according to various embodiments;

[0029] Figure 9 This is a diagram illustrating example methods for identifying the largest quadrilateral region according to various embodiments;

[0030] Figure 10 This is a diagram illustrating example projected images based on trapezoidal correction according to various embodiments;

[0031] Figure 11 It is a diagram illustrating the coordinate system relationships according to various embodiments;

[0032] Figure 12This is a diagram illustrating example methods for obtaining coordinate transformation matrices according to various embodiments;

[0033] Figure 13 This is a diagram illustrating example methods for calculating the width of a quadrilateral according to various embodiments;

[0034] Figure 14 This is a flowchart illustrating example methods for controlling electronic devices according to various embodiments;

[0035] Figure 15 The diagram illustrates an example method for calculating correction information in a stacked configuration according to various embodiments; and

[0036] Figure 16 This is a block diagram illustrating an example configuration of an electronic device according to various embodiments. Detailed Implementation

[0037] The present disclosure will be described in more detail below with reference to the accompanying drawings.

[0038] The terminology used in describing various exemplary embodiments will be briefly explained, and exemplary embodiments will be described in more detail with reference to the accompanying drawings. Considering the configuration and functionality of this disclosure, the terminology used herein has been selected as currently widely used and common terms, but may vary depending on the intent of those skilled in the art, precedent, the emergence of new technologies, etc. Furthermore, in specific cases, terms may be arbitrarily chosen. In such cases, the meaning of the terms will be explained in the description of the corresponding embodiments. Therefore, the terms used in this specification are not necessarily to be interpreted as simple names of the terms, but are defined based on the meaning of the terminology and the overall content of this disclosure.

[0039] The terms “having,” “may have,” “including,” and “may include” used in the exemplary embodiments of this disclosure indicate the presence of a corresponding feature (e.g., an element such as a numerical value, function, operation, or component) without excluding the presence of additional features.

[0040] In this disclosure, expressions such as “A or B”, “at least one of A and / or B” or “one or more of A and / or B” can include all possible combinations of the listed items. For example, “A or B”, “at least one of A and B” or “at least one of A or B” can refer to: (1) only A, (2) only B, or (3) both A and B.

[0041] Terms such as “first” and “second” used in various example embodiments may be used to refer to various elements regardless of the order and / or importance of the corresponding elements, and do not limit the corresponding elements.

[0042] When an element (e.g., a first element) is "operationally or communicatively coupled to / coupled to" or "connected to" another element (e.g., a second element), the element may be directly coupled to the other element or may be coupled through other elements (e.g., a third element).

[0043] In the description, the term "configured to" may be used interchangeably with, in some cases, "suitable for," "capable of," "designed to," "suitable for," "enable to," or "able to." The term "configured to (set to)" does not necessarily mean that it is "specifically designed for" in hardware.

[0044] In some contexts, the phrase "configured as" can mean that the device is "capable" of working in conjunction with other devices or components to perform a task. For example, the phrase "processor configured (or set) to perform A, B, and C" can refer to a processor dedicated to performing these operations (such as an embedded processor), or it can refer to a general-purpose processor (such as a CPU or application processor) that can perform these operations by executing one or more software programs stored in a memory device.

[0045] Unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. The terms “comprising,” “including,” “configured as,” etc., in the specification are used to indicate the presence of features, numbers, steps, operations, elements, parts, and combinations thereof, and they should not exclude the possibility of combination or addition of one or more features, numbers, steps, operations, elements, parts, and combinations thereof.

[0046] In this disclosure, a "module" or "unit" may perform at least one function or operation and may be implemented by hardware or software, or a combination of hardware and software. Furthermore, in addition to "modules" or "units" that should be implemented with specific hardware, multiple "modules" or multiple "units" may be integrated into at least one module and may be at least one processor.

[0047] Furthermore, various elements and areas are schematically depicted in the accompanying drawings. Therefore, the technical concept of this disclosure is not limited to the relative dimensions or spacing shown in the accompanying drawings.

[0048] In the following, various exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings.

[0049] Figure 1a and Figure 1b This is a diagram illustrating an example of the trapezoidal correction method and the concept of a coordinate system for better understanding.

[0050] An electronic device 100 with the function of projecting images (i.e., projector function) displays a relatively accurate screen ratio when the projector is positioned on a straight line within the projection plane. However, when this cannot be achieved due to space constraints, the electronic device 100 projects a screen that deviates from the projection plane or a diamond-shaped screen that is distorted upwards, downwards, leftwards, and rightwards. In this case, keystone correction is required. Keystone correction can refer, for example, to the function of adjusting the projected screen to be closer to the original quadrilateral shape by forcibly moving the edges of the screen to be displayed (i.e., projected).

[0051] According to the embodiments, the following can be used: Figure 1a The user terminal 200 shown is used to perform keystone correction. For example, a camera set in the user terminal 200 can be used to capture an image on a projection plane 10 on which the image is projected, and keystone correction can be performed based on the captured image. Projection transformation can be used. Projection transformation can, for example, refer to the transformation of an image from 3D space to 2D space. In other words, it is a method of transforming two images viewed from two different viewpoints in 3D space. The matrix representing the relationship between the two different images can be called a homography matrix (hereinafter referred to as the H matrix). For example, the size of the H matrix can be 3×3. To obtain the H matrix, four corresponding coordinate pairs may be required. According to an embodiment, the four corresponding coordinate pairs can be coordinates in the world coordinate system.

[0052] Figure 1b This is a diagram illustrating an example concept of a coordinate system for better understanding.

[0053] like Figure 1b As shown, there are four coordinate systems in image geometry: world coordinate system, camera coordinate system, ordinary coordinate system, and pixel coordinate system. The world coordinate system and camera coordinate system are three-dimensional coordinate systems, while the ordinary coordinate system and pixel coordinate system are two-dimensional coordinate systems.

[0054] The world coordinate system is a coordinate system used to represent the position of an object. It is a coordinate system that can be used arbitrarily (for example, the edge of space can be set as the origin, the direction of one wall can be set as the X-axis, the direction of another wall as the Y-axis, and the direction facing the sky as the Z-axis). A point in the world coordinate system can be represented as P(X,Y,Z).

[0055] The camera coordinate system is a coordinate system relative to the camera. For example... Figure 4a and Figure 4b As shown, for example, a camera coordinate system can set the camera's focal point (the center of the lens) as the origin, the camera's front optical axis as the Z-axis, the camera's downward direction as the Y-axis, and the rightward direction as the X-axis. A point in the camera coordinate system can be represented as Pc(Xc,Yc,Zc).

[0056] The pixel image coordinate system can be called the image coordinate system. For example... Figure 1b As shown, the pixel coordinate system can be the coordinate system of the image as actually observed by the eye. The top left edge of the image can be set as the origin, the rightward direction as the x-axis increasing direction, and the downward direction as the y-axis increasing direction. The plane defined by the x-axis and y-axis of the pixel coordinate system is called the image plane.

[0057] Geometrically, a point P = (X, Y, Z) in 3D space can pass through the camera's focal point (or the lens's focal point) and be projected onto the image plane as a point pimg = (x, y). All 3D points on the ray connecting point P and point pimg can be projected onto pimg. Therefore, pimg can be uniquely determined from the 3D point P, but conversely, P cannot be obtained from the image pixel pimg without additional information. The unit of the pixel coordinate system is the pixel, and it can be represented as pimg = (x, y).

[0058] A normalized coordinate system can, for example, refer to an image coordinate system that eliminates and / or reduces the influence of the camera's intrinsic parameters. Alternatively, a normalized coordinate system can, for example, refer to a coordinate system in which coordinate units have been removed (normalized), and is a coordinate system that defines a virtual image plane at a distance of 1 from the camera's focus. In other words, it can be an image plane shifted to a point at a distance of 1 from the camera's focus by translating the original image plane in parallel.

[0059] The origin of the ordinary coordinate system is the midpoint of the image plane (the intersection with the optical axis Zc). A point in the ordinary coordinate system can be represented as p' = (u, v). Even when photographing the same scene from the same position and angle, different images can be obtained depending on the camera used or its settings. A normalized image plane can be used because it allows for more efficient analysis and derivation of common geometric properties within a normalized image plane that eliminates the aforementioned elements.

[0060] When using a projector to project images, keystone correction can be performed to correct the resulting trapezoidal effect. However, while keystone correction adjusts the projection ratio of the screen, it cannot compensate for the screen brightness unevenness that inevitably occurs during keystone correction.

[0061] Therefore, various embodiments for compensating for screen brightness non-uniformity will be described in more detail below.

[0062] Figure 2 This is a block diagram illustrating an example configuration of an electronic device according to various embodiments.

[0063] according to Figure 2The electronic device 100 may include an image projector 110, a memory 120, and at least one processor (e.g., including processing circuitry) 130. The electronic device 100 may be implemented, for example, as a projector for projecting images onto a wall or projection plane, or various types of devices with image projection capabilities.

[0064] Image projector 110 performs the function of outputting an image to a projection plane by projecting light used to represent the image to an external surface. Here, the projection plane can be a portion of the real-world space to which the image is output or a separate projection plane. Image projector 110 can include various specific configurations, such as, but not limited to, at least one of the following light sources: lamps, LEDs and lasers, projection lenses, reflectors, etc.

[0065] Image projector 110 can project images using one of various projection methods, such as cathode ray tube (CRT), liquid crystal display (LCD), digital light processing (DLP), laser, etc. Image projector 110 may include at least one light source.

[0066] The image projector 110 can, for example but not limited to, output images in 4:3 aspect ratio, 5:4 aspect ratio, or 16:9 aspect ratio, depending on the purpose of the electronic device 100 or the user's settings, and can output images at various resolutions (e.g., WVGA (854×480), SVGA (800×600), XGA (1024×768), WXGA (1280×720), WXGA (1280×800), XGA (1280×1024), UXGA (1600×1200), Full HD (1920×1080), etc.).

[0067] Furthermore, the image projector 110 can perform various functions for adjusting the projected image under the control of the electronic device 100. For example, the image projector 110 can perform zoom functions, lens shift functions, etc.

[0068] The memory 120 can store data required for various embodiments. Depending on the data storage purpose, the memory 120 can be implemented as a memory embedded in the electronic device 100, or as a memory that can be attached to and detached from the electronic device 100. For example, data for driving the electronic device 100 can be stored in a memory embedded in the electronic device 100, and data for extended functions of the electronic device 100 can be stored in a memory that can be attached to or detached from the electronic device 100. The memory embedded in the electronic device 100 can be implemented as at least one of the following: volatile memory (e.g., dynamic RAM (DRAM), static RAM (SRAM), or synchronous dynamic RAM (SDRAM)), or non-volatile memory (e.g., one-time programmable ROM (OTPROM), programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), mask ROM, flash ROM, flash memory (e.g., NAND flash or NOR flash), hard disk drive (HDD), or solid-state drive (SSD)). Additionally, the memory that can be attached to or detached from the electronic device 100 can be implemented in, for example but not limited to, the following forms: memory cards (e.g., compact flash memory (CF), secure digital (SD), micro secure digital (micro SD), mini secure digital (mini SD), extreme digital (xD), multimedia card (MMC), etc.), external memory that can be connected to a USB port (e.g., USB memory), etc.

[0069] According to the example, memory 120 can store various information associated with keystone correction and various information associated with brightness correction. For example, memory 120 can store various information acquired during the performance of keystone correction, such as a transformation matrix. For example, memory 120 can store various information acquired during brightness correction, such as brightness correction coefficients.

[0070] One or more processors 130 may include various processing circuits and control the overall operation of electronic device 100. Specifically, one or more processors 130 may control the overall operation of electronic device 100 by being connected to each configuration of electronic device 100. For example, one or more processors 130 may be operationally connected to image projector 110 and memory 120. Processor 130 may be formed of one or more processors.

[0071] One or more processors 130 can perform the operation of electronic device 100 according to various embodiments by executing at least one instruction stored in memory 120.

[0072] One or more processors 130 may include one or more of a central processing unit (CPU), a graphics processing unit (GPU), an accelerated processing unit (APU), a multi-integrated core (MIC), a digital signal processor (DSP), a neural processing unit (NPU), a hardware accelerator, or a machine learning accelerator. One or more processors 130 may control one or a random combination of other elements of an electronic device and perform operations associated with communication or data processing. One or more processors 130 may execute one or more programs or instructions stored in memory. For example, one or more processors may perform methods according to various embodiments of this disclosure by executing one or more instructions stored in memory.

[0073] When a method according to various embodiments of the present disclosure includes multiple operations, the multiple operations may be executed by a single processor or by multiple processors. For example, when the first operation, the second operation, and the third operation are performed according to the methods of various embodiments, the first operation, the second operation, and the third operation may all be executed by a first processor, or the first operation and the second operation may be executed by a first processor (e.g., a general-purpose processor), while the third operation may be executed by a second processor (e.g., an artificial intelligence-specific processor).

[0074] One or more processors 130 may be implemented as a single-core processor including one core, or as one or more multi-core processors including multiple cores (e.g., homogeneous multi-core or heterogeneous multi-core). If one or more processors 130 are implemented as multi-core processors, each of the multiple cores included in the multi-core processor may include on-processor memory, such as cache memory and on-chip memory, and a common cache shared by the multiple cores may be included in the multi-core processor. Additionally, each (or a portion of) the multiple cores included in the multi-core processor may independently read and execute program instructions for implementing the methods according to various embodiments, or, due to the overall (or partial) interconnection of the multiple cores, program instructions for implementing the methods according to various embodiments of this disclosure may be read and executed.

[0075] When the methods according to various embodiments of this disclosure include multiple operations, these multiple operations can be executed by one of a plurality of cores or by a plurality of cores included in a multi-core processor. For example, when the first operation, the second operation, and the third operation are performed by the methods according to various embodiments, all of the first operation, the second operation, and the third operation can be executed by the first core included in the multi-core processor, or the first operation and the second operation can be executed by the first core included in the multi-core processor, while the third operation can be executed by the second core included in the multi-core processor.

[0076] In various embodiments of this disclosure, a processor may refer to a system-on-a-chip (SoC), a single-core processor, or a multi-core processor integrating one or more processors and other electronic components, or a core included in a single-core processor or multi-core processor. The core described herein may be implemented as a CPU, GPU, APU, MIC, DSP, NPU, hardware accelerator, machine learning accelerator, etc., but is not limited to the various embodiments of this disclosure. For ease of description, one or more processors 130 are hereinafter referred to as processor 130. In other words, processor 130 may include various processing circuitry and / or multiple processors. For example, as used herein (including the claims), the term "processor" may include various processing circuitry including at least one processor, wherein one or more of the at least one processor may be configured individually and / or collaboratively in a distributed manner to perform the various functions described herein. As used herein, when "processor," "at least one processor," and "one or more processors" are described as being configured to perform multiple functions, these terms cover, for example, but not limited to, a situation where one processor performs some of the functions while another processor performs other functions, and also cover a situation where a single processor can perform all of the functions. Additionally, at least one processor may include, for example, a combination of processors that perform various described / disclosed functions in a distributed manner. At least one processor may execute program instructions to implement or perform various functions.

[0077] According to an embodiment, processor 130 can perform keystone correction by projecting a test image onto a screen (or projection plane). The test image, according to the example, can be a white image, but is not limited thereto.

[0078] The processor 130 can control the image projector 110 to project a test image in which multiple markers (or labels) are each contained within a different region. For example, the test image may be an image that only includes multiple markers. However, although the test image may include other images besides multiple markers, the included other images (e.g., a background image) do not overlap with the locations where the multiple markers are located.

[0079] According to the example, each of the multiple marks can be a pattern in which black and white areas are formed in each of the multiple directions in a preset proportion.

[0080] According to the example, multiple markers can be located at predefined (e.g., specified) locations (e.g., a region within a threshold distance of the four vertices of the test image of the image). For example, multiple markers can test the four vertices of the image, located in an inner region at a preset scale relative to the size of the entire image.

[0081] According to an embodiment, the processor 130 can identify screen reference coordinates corresponding to each of the plurality of pixels included in the test image based on keystone correction. For example, the plurality of screen reference coordinates corresponding to each of the plurality of pixels may include four vertex coordinates based on the screen, corresponding to the four vertices of each of the plurality of pixels included in the test image.

[0082] According to an embodiment, processor 130 can identify the screen reference area corresponding to each of the plurality of pixels based on the identified screen reference coordinates. For example, processor 130 can calculate the screen area of ​​each of the plurality of pixels based on the screen-referenced coordinates of the four vertices of each of the plurality of pixels.

[0083] According to an embodiment, the processor 130 can identify a reference pixel from among the plurality of pixels based on a screen reference area corresponding to each of the plurality of pixels. For example, the processor 130 can identify the pixel corresponding to the largest area among the screen reference areas corresponding to each of the plurality of pixels as the reference pixel.

[0084] According to an embodiment, processor 130 can identify brightness correction information corresponding to each of the plurality of pixels based on the screen reference area of ​​the identified reference pixel and the screen reference area of ​​each of the plurality of pixels. For example, processor 130 can identify the value obtained by dividing the screen reference area of ​​each of the plurality of pixels by the screen reference area of ​​the reference pixel as the brightness correction information corresponding to each of the plurality of pixels. For example, the brightness correction information may be a correction coefficient that applies a gain to (or multiplies) the grayscale value of the pixel.

[0085] According to an embodiment, the processor 130 can identify brightness correction information corresponding to each of the plurality of pixels in a stacked configuration. Here, a stacked configuration can refer to using multiple projectors to implement a screen. For example, a screen can be implemented by using two projectors to project two projected images onto a single screen. In this case, a relatively brighter screen can be achieved compared to using a single projector.

[0086] According to an embodiment, the processor 130 can identify, in a stacked configuration, the area where a first test image projected onto the screen according to keystone correction overlaps with a second test image projected onto the screen from an external projector device.

[0087] According to an embodiment, the processor 130 can identify overlapping areas on the screen as multiple virtual pixel regions. For example, the region where the first test image and the second test image overlap can be a quadrilateral region of the largest size identified in the region where the first test image and the second test image overlap, based on the aspect ratio of the first test image and the aspect ratio of the second test image.

[0088] According to an embodiment, the processor 130 can identify projector reference coordinates corresponding to each of the plurality of virtual pixel areas.

[0089] According to an embodiment, the processor 130 can identify screen reference coordinates corresponding to the identified projector reference coordinates.

[0090] According to an embodiment, the processor 130 can acquire third brightness information corresponding to each of a plurality of virtual pixel regions based on first brightness information corresponding to the identified screen reference coordinates and second brightness information corresponding to the external projector device.

[0091] According to the example, the processor 130 can obtain third brightness information by adding first brightness information of a first pixel corresponding to the identified screen reference coordinates and second brightness information of a second pixel corresponding to the screen reference coordinates identified by the external projector device.

[0092] According to the example, the processor 130 can receive second brightness information from an external projector device through the communication interface 140, obtain second brightness correction information corresponding to each of the plurality of pixels of the second test image based on the second brightness information and the third brightness information, and send the obtained second brightness correction information to the external projector device through the communication interface 140.

[0093] According to an embodiment, processor 130 can identify first brightness correction information corresponding to each of the plurality of pixels included in the first test image based on first brightness information and third brightness information. For example, processor 130 can identify a first pixel region with the lowest brightness from among the plurality of virtual pixel regions based on the third brightness information. Processor 130 can identify a brightness compensation value corresponding to each of the plurality of virtual pixel regions based on fourth brightness information corresponding to the first pixel region and the first brightness information of each of the plurality of virtual pixel regions. Processor 130 can identify the first brightness correction information corresponding to each of the plurality of pixels included in the first test image based on the identified brightness compensation value.

[0094] Figure 3 This is a flowchart illustrating an example method for controlling an electronic device according to various embodiments.

[0095] refer to Figure 3 The electronic device 100 can perform keystone correction by projecting the test image onto the screen (S310).

[0096] The electronic device 100 can identify screen reference coordinates corresponding to each of the plurality of pixels included in the test image based on keystone correction (S320). For example, the plurality of screen reference coordinates corresponding to each of the plurality of pixels may include four vertex coordinates based on the screen corresponding to the four vertices of each of the plurality of pixels included in the test image.

[0097] The electronic device 100 can identify the screen reference area corresponding to each of the plurality of pixels based on the identified screen reference coordinates (S330). For example, the electronic device 100 can calculate the screen area of ​​each of the plurality of pixels based on the four vertex coordinates of each of the plurality of pixels relative to the screen.

[0098] The electronic device 100 can identify a reference pixel from among the multiple pixels based on the screen reference area corresponding to each of the multiple pixels (S340). For example, the electronic device 100 can identify the pixel corresponding to the largest area among the screen reference areas corresponding to each of the multiple pixels as the reference pixel.

[0099] Electronic device 100 can identify brightness correction information corresponding to each of the plurality of pixels based on the screen reference area of ​​the identified reference pixel and the screen reference area of ​​each of the plurality of pixels (S350). For example, electronic device 100 can identify the value obtained by dividing the screen reference area of ​​each of the plurality of pixels by the screen reference area of ​​the reference pixel as brightness correction information corresponding to each of the plurality of pixels.

[0100] exist Figure 3 In this document, for ease of description, the order of each step is mapped. However, the order of the steps is not necessarily limited to this order and may include steps that are independent of the order or can be executed in parallel.

[0101] The following will refer to Figures 4a to 10 The trapezoidal correction method is described in more detail.

[0102] According to an embodiment, the electronic device (100) can obtain third information based on first information indicating the positions of multiple markers in a test image and second information indicating the positions of multiple markers in a captured image obtained by capturing the screen through an external device (e.g., a user terminal including a camera), the third information indicating the vertex positions of the test image in the captured image. Thereafter, the electronic device (100) can correct the third information based on pose information from the external device, and can perform trapezoidal correction based on the corrected third information.

[0103] According to the example, the electronic device (100) can control the image projection unit (110) to project a test image containing each of a plurality of marks (or labels) in a different area onto a screen. For example, the test image may contain only the plurality of marks. However, the test image may also include an additional image in addition to the plurality of marks, and the included additional image (e.g., a background image) does not overlap with the location of the plurality of marks.

[0104] According to the example, each of the multiple marks can have a pattern in which black and white areas are configured in multiple directions at a preset ratio.

[0105] According to the example, multiple markers can be located at predefined locations, such as within an inner region at a threshold distance from the four vertices of the test image. For example, multiple markers can be located within the inner region based on the four vertices of the test image, at a preset scale relative to the overall size of the image.

[0106] According to the example, the electronic device (100) can obtain first information indicating the positions of multiple markers in a test image and second information indicating the positions of multiple markers in an image obtained by capturing the screen through an external device (hereinafter referred to as the captured image). Here, the external device may be a user terminal including a camera, and the following description is based on the assumption that the external device is a user terminal.

[0107] According to an embodiment, electronic device 100 can acquire first information indicating the positions of multiple markers in an original test image projected by image projector 110.

[0108] The electronic device 100 can receive the second information from the user terminal 200, or obtain the second information based on the captured image received from the user terminal 200. For example, the user terminal 200 can directly identify the second information indicating the location of multiple markers in the captured image and send it to the electronic device 100, and the electronic device 100 can directly obtain the second information based on the received captured image.

[0109] For ease of description, the coordinates of the original test image are described in the projector coordinate system, and the coordinates of the captured image are described in the camera coordinate system. Therefore, the first information can correspond to the projector coordinate system, and the second information can correspond to the camera coordinate system. For ease of description, the first information and the second information are named first coordinate information and second coordinate information.

[0110] Figure 4a and Figure 4b This is a diagram illustrating example coordinate information according to various embodiments.

[0111] Figure 4aIt is a graph showing the first coordinate information of multiple markers 411, 412, 413, and 414 in the original test image (e.g., a projector coordinate system), and the first coordinate information can be P1, P2, P3, and P4. For example, the first coordinate information can be calculated based on specific points (e.g., center points) of the multiple markers 411, 412, 413, and 414.

[0112] Figure 4b This is a diagram showing the second coordinate information of multiple markers 411, 412, 413, and 414 in the captured image (i.e., the camera coordinate system), and the second coordinate information can be C1, C2, C3, and C4. For example, the second coordinate information can be calculated based on specific points (the same points as the first coordinate information) (e.g., the center point) of the multiple markers 411, 412, 413, and 414.

[0113] Return to reference Figure 2 The electronic device 100 can acquire third information indicating the vertex region position of the test image in the captured image based on the first coordinate information and the second coordinate information. The vertex region can be four points where each edge region intersects. The third information can be coordinate information in the camera coordinate system, and for ease of description, it can be named third coordinate information.

[0114] According to an embodiment, the electronic device 100 can obtain fourth information indicating the position of a vertex in the test image based on the position information of the marker and the first coordinate information, and obtain third coordinate information in the captured image based on the first H matrix. The fourth information may be coordinate information in the projector coordinate system, and for ease of description, it can be named the fourth coordinate information.

[0115] In this case, the first H matrix can be obtained based on the mapping relationship between the first coordinate information and the second coordinate information. According to the embodiment, the electronic device 100 knows four coordinate pairs based on the first coordinate information P1, P2, P3 and P4 and the second coordinate information C1, C2, C3 and C4, thereby obtaining the first H matrix.

[0116] The electronic device 100 can use the first H matrix to convert the coordinates of four vertices in the projector coordinate system (e.g., the fourth coordinate information) into the camera coordinate system (e.g., the third coordinate information). For example, the electronic device 100 can pre-store the coordinate information of four vertices in the test image (e.g., the fourth coordinate information in the projector coordinate system), or calculate the coordinates of four vertices (e.g., the fourth coordinate information in the projector coordinate system) based on the first coordinate information.

[0117] For example, each of the multiple markers may be located within an interior region at a predetermined scale based on the four vertices of the test image. In this case, the electronic device 100 can acquire fourth coordinate information indicating the vertex positions of the test image based on first coordinate information indicating the position of the marker and the predetermined scale. The fourth coordinate information may correspond to the projector coordinate system.

[0118] The electronic device 100 can obtain the third coordinate information by using the first H matrix to transform the coordinates of the four vertices (fourth coordinate information) in the projector coordinate system to the camera coordinate system. For example, as Figure 5 As shown, the electronic device 100 can acquire third coordinate information C5, C6, C7 and C8 (i.e., third coordinate information of the camera coordinate system) corresponding to the four vertices 511, 512, 513 and 514 of the projected image in the captured image.

[0119] Return to reference Figure 2 Although the electronic device 100 acquires third coordinate information indicating the vertex position of the test image in the captured image, it may be necessary to correct the third coordinate information because it is difficult to assume that the user terminal 100 performed the capture in the correct posture.

[0120] Therefore, the electronic device 100 can correct the third coordinate information based on the posture information of the user terminal 200. The posture information may include at least one of roll information, pitch information, or yaw information. According to an embodiment, roll and pitch information can be obtained using an accelerometer located in the user terminal 200. Yaw information can be obtained based on the viewing angle information of a camera in the user terminal 200 used to capture the projection plane.

[0121] During the calibration process, the electronic device 100 can calibrate the third coordinate information based on the distance information between the user terminal 200 and the projection plane, as well as the posture information. For example, the electronic device 100 can perform rotational calibration on the third coordinate information based on the posture information and projection calibration on the third coordinate information based on the distance information.

[0122] The following describes example rotation correction and projection correction methods.

[0123] Figure 6a and Figure 6b This is a diagram illustrating example methods for obtaining roll and pitch information according to various embodiments.

[0124] According to the embodiment, if as Figure 6a As shown, based on the user terminal 200, the Xc, Yc and Zc axes are defined. Then the roll angle φ around the y-axis and the pitch angle θ around the x-axis can be as follows.

[0125] Equation 1

[0126] Equation 2

[0127] In equation 1, A X A Y A Z These are the x-axis, y-axis, and z-axis acceleration values ​​of the accelerometer sensor installed in the user terminal 200. For example, it can be based on... Figure 6b The relationship shown is used to calculate the pitch angle θ.

[0128] Figure 7 This is a diagram illustrating example methods for obtaining yaw information according to various embodiments.

[0129] Attitude information related to the direction of gravity (e.g., roll and pitch information) can be obtained using the output values ​​of an accelerometer (or gravity sensor) as described above. However, yaw information independent of the direction of gravity can be obtained using a geomagnetic sensor, gyroscope, etc., based on a direction arbitrarily specified by the user. However, when a gyroscope, etc., is not used, yaw information can be obtained based on the camera's viewpoint information. For example, the electronic device 100 can obtain the coordinates of the center point of the projected image in the camera coordinate system based on the third coordinate information C5, C6, C7, and C8 corresponding to the four vertices 511, 512, 513, and 514 of the projected image in the captured image. The electronic device 100 can obtain the pixel distance value between the center point coordinates of the projected image and the center point coordinates of the captured image. The electronic device 100 can obtain the camera rotation angle based on the distance value between the entire viewpoint: the entire pixel = camera rotation angle: the pixel distance value. For example, if the overall viewing angle is 80', the total pixel count is 4000px, and the pixel distance value is 500px, then the camera rotation angle of 10' can be obtained based on 80':4000px = camera rotation angle:500px.

[0130] According to an embodiment, if the projection plane is identified as a predetermined area based on the posture information of the external device 200, the electronic device 100 can obtain at least one of roll information, pitch information and yaw information by changing the reference value of the gravity direction in the output value of the accelerometer.

[0131] For example, even if the projection plane is a ceiling other than a regular wall or a wall in the same or similar direction as the direction of gravity, the image can be projected by rotating it 90 degrees. In this case, the electronic device 100 can acquire at least one of roll, pitch, or yaw information by changing the reference value of the gravity direction in the output value of the accelerometer. For example, if the reference value of the gravity direction in the output value of the accelerometer is based on the x-axis value when the projection plane is a regular wall, then when the projection plane is a ceiling, the reference value of the gravity direction can be changed to a y-axis value or a z-axis value, and at least one of roll, pitch, or yaw information can be acquired. In this case, if the x-axis value of the reference value in the gravity direction exceeds a threshold, or even if the projection plane is a wall, the electronic device 100 can determine that the projection plane is a ceiling rather than a regular wall when the image is projected by rotating it 90 degrees. Therefore, even if the projection plane is a ceiling rather than a regular wall or wall, calculation errors caused by the posture information of the external device 200 can be prevented and / or reduced when the projection plane is projected by rotating it 90 degrees.

[0132] According to an embodiment, the electronic device 100 can acquire distance information between the user terminal 200 and the projection plane.

[0133] According to an embodiment, the electronic device 100 can acquire distance information to a virtual plane in pixels rather than an actual projection plane, wherein a camera image is projected onto the virtual plane. The virtual plane in pixels can be... Figure 1b The pixel coordinate system described in the text.

[0134] According to an embodiment, when the user terminal 200 is equipped with a distance sensor (e.g., a ToF sensor), if the distance (z-axis value) of each vertex can be known from the user terminal 200, the real-world distance of the z-axis can be calculated in pixels (px), and the z-axis value can be scaled in pixels. Since the distance between x-axis pixels and y-axis pixels can be identified by capturing an image, and the corresponding real-world distance can be identified based on the ToF sensor, the same method can be used to calculate the ratio between pixels and the real-world distance to calculate the z-axis in pixels.

[0135] According to another example, when the user terminal 200 does not have a distance sensor and the camera's perspective information is known, distance information can be obtained based on the lens's (sensor's) perspective information. For example, the lens's perspective information can be obtained from an exchangeable image file format (EXIF).

[0136] For example, the focal length and the real-world proportions of the screen diagonal can be fixed based on the viewing angle, such as... Figure 8aAs shown. The screen diagonal can be obtained based on the number of diagonal pixels, and the distance to the object can correspond to the focal length. In other words, if two points of the imaged object are 1000px on the xy-plane, the screen diagonal is 2000px, and the ratio of the focal length to the screen diagonal is 2:1, then the z-axis distance between the camera and the two points on the xy-plane is 2:1 = x:2000, therefore this distance can be 4000px. In other words, the xy-plane can be 4000px away from the camera on the z-axis.

[0137] According to another example, since the camera lacks a ToF sensor and information such as focal length, the field of view is completely unknown. Therefore, errors can be considered, and calculations can be performed by inputting approximately 75 degrees, which is the lens field of view commonly used in user terminals. According to an embodiment, information about the camera can be received via an external server. For example, the camera manufacturer or keystone correction service provider can store camera information on a cloud server, etc. In this case, the electronic device 100 can receive the camera's field of view information from the external server. For example, the camera's field of view information may include information such as sensor size and focal length. Figure 8b As shown, the focal length of a camera is inversely proportional to its field of view. In other words, the shorter the focal length, the wider the field of view, while the longer the focal length, the narrower the field of view.

[0138] When the user terminal 200's posture information and the distance information between the user terminal 200 and the projection plane are acquired, the electronic device 100 can correct the third coordinate information based on the acquired information.

[0139] For example, the electronic device 100 can perform rotation correction on the third coordinate information based on the posture information of the user terminal 200, perform projection correction on the third coordinate information that has already been rotated based on the distance information, and obtain the corrected third coordinate information.

[0140] The captured image identifies the coordinates of the camera's projection plane; however, the position of the projection plane in 3D space is unknown, thus requiring 3D rotation correction. This position could be known if a ToF sensor is present, but this is assumed not to be used. Alternatively, a method for generating a virtual image can be employed by assuming the projection plane is not tilted after correction and is perpendicular to the user's gravity. For example, suppose four virtual points a1, a2, a3, and a4 are generated, all with identical Z-axis values. In this case, pose information (i.e., the reciprocals of roll, pitch, and yaw values) can be applied as correction values, and the point angles b1, b2, b3, and b4 of the camera's imaging plane and the tilt relationship plane can be obtained. A transformation equation is then obtained from the plane including points b1, b2, b3, and b4 to the plane including points a1, a2, a3, and a4. Specifically, a transformation equation for rotational transformation, such as Equation 3 below, can be obtained.

[0141] Equation 3

[0142] Based on Equation 3, the electronic device 100 can perform rotation correction on the third coordinate information and acquire the rotated third coordinate information. Therefore, it is possible to acquire the rotated third coordinate information, i.e., the coordinates of a point in three-dimensional space.

[0143] The electronic device 100 can calculate how to project the 3D coordinates obtained through the aforementioned rotation correction onto the actual camera imaging plane. In other words, the electronic device 100 can perform projection correction on the 3D coordinates obtained through rotation correction and obtain the final corrected third coordinate information. (Reference) Figure 1b Points in 3D on the camera coordinate system can be projected onto the imaging plane along a virtual vanishing point line passing through the camera sensor. Therefore, the electronic device 100 can calculate how points on the 3D camera coordinate system will be projected onto the 2D imaging plane (e.g., a two-dimensional ordinary coordinate system).

[0144] For example, if the projection reference point is set to the origin, the transformation equation for projecting a point P in 3D to p' can be shown in Equation 4.

[0145] Equation 4

[0146] According to Equation 4, when the projection plane is Zc=d, (Xc,Yc,Zc,1) can be projected as (Xc,Yc,Zc / d)=(d×Xc / Zc,d×Yc / Zc,1).

[0147] As described above, the electronic device 100 can perform projection correction on the third coordinate information that has already undergone rotation correction, and obtain the finally corrected third coordinate information.

[0148] However, in the example above, projection correction was performed after rotation correction, but rotation correction can also be performed after projection correction.

[0149] Return to reference Figure 2 The electronic device 100 can obtain a transformation matrix, such as a second H matrix, based on the final corrected third coordinate information and the vertex coordinates of the test image. Here, the final corrected third coordinate information and the vertex coordinates of the test image can be coordinates in a general coordinate system (or pixel coordinate system). For example, if the final corrected third coordinate information (i.e., the four vertex coordinates) are d1, d2, d3, d4 and the four vertex coordinates of the actual projection point of the test image are e1, e2, e3, e4, then the second H matrix can be obtained based on the four pairs (d1, e1), (d2, e2), (d3, e3), and (d4, e4). For example, if it is an FHD resolution projector, then e1, e2, e3, and e4 can be (0, 0), (1920, 0), (0, 1080), and (1920, 1080).

[0150] The electronic device 100 can also identify a rectangular region within the region identified based on the corrected third coordinate information, which has the largest size corresponding to the aspect ratio of the input image, and acquire fifth information corresponding to the identified rectangular region. For example, the fifth information may include the coordinate information of each vertex of the identified rectangular region, and for ease of description, it will be referred to as the fifth coordinate information below.

[0151] In this configuration, the electronic device 100 can extend the quadrilateral vertically and horizontally by the same size, starting from the center point where the vertices of the first region obtained based on the corrected third coordinate information are diagonally connected, and identify whether the vertices of the quadrilateral intersect the edge of the first region. Furthermore, when the vertices of the extended quadrilateral intersect the edge of the first region, the electronic device 100 can extend the shorter side of the rectangle by a predetermined pixel unit, and can correspondingly extend the longer side of the quadrilateral according to the aspect ratio. The electronic device 100 can identify the largest rectangular region at the location where the vertices corresponding to the diagonals of the extended quadrilateral intersect the edge of the first region.

[0152] Figure 9 This is a diagram illustrating example methods for identifying the largest rectangular region according to various embodiments.

[0153] like Figure 9As shown, when the corrected third coordinate information d1, d2, d3 and d4 (e.g., vertices 911, 912, 913 and 914) is obtained, the quadrilateral can be expanded starting from the center point 920 that intersects diagonally with each vertex.

[0154] According to an embodiment, a quadrilateral is expanded upwards, downwards, leftwards, and rightwards from a starting point 920 with the same dimensions, and it is identified whether there is a portion that extends beyond the projection plane 910 of the projector. When there is no portion extending beyond the projection plane 910, the quadrilateral can be expanded according to a predetermined proportion of the screen (e.g., 5%), and it is identified whether the vertices of the expanded quadrilateral intersect with the edge of the projection plane of the projector.

[0155] When any edge of the projection plane 910 intersects with vertices 931, 932, 933, and 934 of quadrilateral 930, the shorter side of quadrilateral 930 can be extended by a predetermined pixel unit (e.g., 1px), and the longer side of quadrilateral 930 can be extended proportionally. For example, if the upper left, upper right, lower left, and lower right edges of quadrilateral 930 intersect with a point on the projection plane 910, the intersection of the vertex and the edge of the projection plane 910 is identified by moving 1px towards the opposite edge, and then the existence of an intersection point is identified by extending the size by 1px. If the extended upper left, upper right, lower left, and lower right edges of quadrilateral 930 intersect with a non-diagonal vertex, the intersection point is identified by moving 1px in opposite directions (vertical and horizontal), and then the existence of an intersection point is identified by extending the size by 1px.

[0156] The expansion can end when vertices 942 and 943, located on the diagonals of the extended quadrilateral 930, intersect the boundary line of the projection plane 910, and the coordinates g1, g2, g3, and g4 of the final vertices 941, 942, 943, and 944 can be obtained. Furthermore, to prevent and / or reduce the infinite movement of the quadrilateral's position, the process can be terminated if the quadrilateral moves back to its previous position, provided the quadrilateral size remains the same.

[0157] Return to reference Figure 2 The electronic device 100 can perform trapezoidal correction by applying the inverse of the second H matrix to the acquired fifth coordinate information. For example, if the coordinates of the vertices corresponding to the largest square are g1, g2, g3, and g4, the inverse of the second H matrix can be applied to obtain the coordinates of the projection area to be projected onto the electronic device 100. In other words, when the electronic device 100 projects an image based on coordinates, the user can see the largest rectangular area.

[0158] However, while the example above describes correcting the vertex coordinates of the projected image based on camera pose information, it is also possible to correct the marker coordinates based on camera pose information. In this case, after correcting the marker coordinates, the vertex coordinates of the projected image can be obtained based on the corrected marker coordinates. In other words, when correcting the marker coordinates based on camera pose information, it is not necessary to correct the vertex coordinates based on camera pose information.

[0159] Figure 10 These are diagrams of example projected images with trapezoidal correction according to various embodiments.

[0160] exist Figure 10 In the diagram, vertices 941, 942, 943, and 944 correspond to the fifth coordinate information, and the region identified by the vertex can, for example, refer to... Figure 9 The largest rectangular region obtained from the data. In this case, the electronic device 100 can apply the inverse of the second H matrix to the fifth coordinate information and determine the coordinates of the image to be projected. In other words, the electronic device 100 can determine the vertex coordinates 951, 952, 953, and 954 of the trapezoidally corrected image by applying the inverse of the second H matrix to the coordinates of vertices 941, 942, 943, and 944. In this case, since the electronic device 100 projects the image based on vertices 951, 952, 953, and 954, a distorted image 950 is projected, but the user can see a rectangular image 960.

[0161] When performing keystone correction as described above, the projection area can be a random quadrilateral based on the projector, or it can be a rectangle based on the screen. For example, as Figure 11 As shown, assuming the projector is an FHD resolution projector, and the projector reference coordinates used to project the rectangle based on the screen are (200,0), (1919,170), (190,1079), and (1880,950) in the order of top left, top right, bottom left, and bottom right, then the screen reference coordinates of the four vertices can be set to (0,0), (1920,0), (0,1080), and (1920,1080) to match the 16:9 aspect ratio.

[0162] According to an embodiment, the electronic device 100 can identify the screen reference coordinates corresponding to each pixel included in the test image. For example, the electronic device 100 needs to convert the coordinates of each pixel included in the test image into screen-based coordinates to identify which corresponding size of the screen reference coordinates each pixel, based on the projector, is being projected onto. Therefore, the electronic device 100 can obtain a transformation matrix for identifying the screen reference coordinates corresponding to each pixel, based on the projector.

[0163] According to the example, electronic device 100 can obtain a coordinate transformation matrix (or an inter-plane projection relationship transformation matrix) based on the projector reference coordinates and the screen reference coordinates. For example, Figure 12 As shown, the electronic device 100 can be based on the projector coordinates P P and screen coordinates P S The coordinate transformation matrix is ​​obtained by constructing pairs. For example, if the projector coordinates P P The coordinates of the four vertices are d1, d2, d3, and d4, and the screen coordinates are P. S If the coordinates of the four vertices are e1, e2, e3, and e4, then the transformation matrix can be obtained based on the four pairs (d1, e1), (d2, e2), (d3, e3), and (d4, e4). For example, in the case of an FHD resolution projector, e1, e2, e3, and e4 could be (0, 0), (1920, 0), (0, 1080), and (1920, 1080). According to the example, the coordinate transformation matrix can be the second H matrix mentioned above.

[0164] According to the example, the coordinate transformation matrix can be represented by the following equation 5.

[0165] Equation 5

[0166] According to an embodiment, the electronic device 100 can obtain screen reference coordinates corresponding to each pixel relative to the projector based on a coordinate transformation matrix (S320).

[0167] According to the example, in Figure 11 In this context, the projection area based on the projector can be an atypical quadrilateral ranging from 200,0 to 1880,950. The electronic device 100 can continuously calculate the screen transformation coordinates of each pixel from (0,0) to (1919,1079) based on the FHD resolution projector. For example, the electronic device 100 can continuously calculate the screen reference transformation coordinates of each pixel from (0,0) to (1919,1079), excluding the black area outside the keystone correction region. For example, the electronic device 100 can calculate the four vertex coordinates of each pixel relative to the screen by applying a second H matrix to the four vertex coordinates of each pixel relative to the projector.

[0168] According to the example, the projector's reference pixel can be 1×1 in size, but it can be a non-typical quadrilateral relative to the screen (e.g., 1101, 1102). For example, the top-left pixels (200, 0) to (201, 1) relative to the projector can have a width of 1 unit, but it can be a quadrilateral with angular coordinates (0, 0), (1.01, 0.04), (0.007, 1.0), and (1.004, 1.05) relative to the screen. Figure 11 As shown, in the projector coordinate system, each pixel can be a square (e.g., 1×1), but in the screen coordinate system, each pixel may have a random shape that is not necessarily a square or a rectangle. For example, based on forward projection, areas relatively close to the projector may become brighter because the pixels become smaller, while areas relatively far away may become darker because the pixels become larger.

[0169] According to the example, based on the calculated screen reference coordinates corresponding to each pixel relative to the projector, the electronic device 100 can calculate the screen reference area relative to each pixel of the projector based on the calculated coordinates (S330). For example, the electronic device 100 can calculate the screen reference area relative to each pixel of the projector based on the coordinates of the four vertices of each pixel relative to the screen.

[0170] Based on the example, if the coordinates of the four vertices of a quadrilateral are known, the area of ​​the quadrilateral can be calculated. For example, refer to... Figure 13 The area of ​​a quadrilateral can be calculated using the triangle area equation. Suppose there exists a line connecting the point between lines a and b to the point between lines c and d; this line divides the quadrilateral into two distinct triangles. The area of ​​a triangle can be ab × sinC, since angle C is the angle between sides a and b. Since there are two triangles in total, the equation can be used twice to calculate the area of ​​the quadrilateral, and the results can be added together. Therefore, the area of ​​the quadrilateral can be calculated based on the following equation: length of side 1 × length of side 4 × sin(angle between side 1 and side 4) + 0.5 × length of side 2 × length of side 3 × sin(angle between side 2 and side 3), i.e., 0.5 × a × d × sinA + 0.5 × b × c × sinC. Therefore, assuming a is 12, b is 9, c is 5, d is 12, A is 80°, and C is 110° (a=12, b=9, c=5, d=12, A=80°, C=110°), the area of ​​the quadrilateral can be calculated as follows.

[0171] Area of ​​quadrilateral = 0.5(12×14)×sin(80) + 0.5×(9×5)×sin(110)

[0172] =84×sin(80)+22.5×sin(110)

[0173] =84×0.984+22.5×0.939

[0174] =82.66 + 21.13 = 103.79cm 2

[0175] When trying to find the area of ​​a parallelogram, since the values ​​of opposite angles are the same, the equation used to find the area can be simplified to, for example, area = 0.5 × (ad + bc) × sinA.

[0176] According to an embodiment, the electronic device 100 can identify a reference pixel based on the screen reference area of ​​each pixel (S340). For example, the electronic device 100 can identify the pixel corresponding to the largest area among the screen reference areas corresponding to each pixel as the reference pixel. Since the area of ​​a pixel is inversely proportional to its brightness, the pixel with the largest area can have the lowest brightness. Since the maximum brightness that can usually be output by each projector is preset, it is easy to adjust the brightness downwards, but it may be difficult to adjust the brightness upwards. Therefore, the above-mentioned objective is to match the brightness uniformity with the brightness of the relevant pixels.

[0177] According to an embodiment, the electronic device 100 can identify brightness correction information corresponding to each pixel based on the screen reference area of ​​the identified reference pixel and the screen reference area of ​​each pixel (S350). As an example, the electronic device 100 can identify the value obtained by dividing the screen reference area of ​​each pixel by the screen reference area of ​​the reference pixel as brightness correction information corresponding to each pixel. For example, the electronic device 100 can identify the brightness correction ratio (or brightness adjustment gain) of each pixel based on "pixel area / reference pixel area".

[0178] According to an embodiment, the electronic device 100 may store brightness correction information calculated for each pixel in the memory 120. For example, the electronic device 100 may store the calculated brightness correction information in the memory 120 in the form of a lookup table (LUT), which includes a brightness correction ratio (or brightness adjustment gain) corresponding to each pixel. The lookup table may refer to a data structure formed by keys and values ​​to quickly retrieve previously stored values ​​without having to perform separate calculations, and may be a table mapping the brightness adjustment ratio corresponding to the position (or coordinates) of each pixel.

[0179] According to an embodiment, the electronic device 100 can correct the grayscale of an image based on the brightness correction information of each pixel stored in the memory 120, thereby projecting an image with corrected grayscale. For example, when projecting a specific image based on the electronic device 100, the corrected grayscale value can be obtained by multiplying by a brightness adjustment ratio corresponding to the grayscale value of each pixel forming the associated image, and the image including the corrected grayscale value is projected onto the screen. Therefore, since the pixel brightness of the projected image becomes uniform, the user can see a uniform image.

[0180] Figure 14 This is a flowchart illustrating an example method for controlling an electronic device according to various embodiments.

[0181] According to an embodiment, the electronic device 100 can identify brightness correction information corresponding to each of a plurality of pixels in a stacked configuration. A stacked configuration may refer to using multiple projectors to implement a single screen.

[0182] refer to Figure 14 The electronic device 100 can identify the area where a first test image projected onto the screen according to keystone correction overlaps with a second test image projected onto the screen from an external projector device (S1410). According to an example, the overlapping area of ​​the first and second test images can be a quadrilateral region of the largest size identified based on the aspect ratios of the first and second test images. For example, if the electronic device 100 and the external projector device use an FHD resolution projector, this area can be a quadrilateral region of the largest size corresponding to the FHD aspect ratio.

[0183] The electronic device 100 can identify overlapping areas on the screen as multiple virtual pixel areas (S1420).

[0184] The electronic device 100 can identify the projector reference coordinates corresponding to each of the multiple virtual pixel regions (S1430).

[0185] The electronic device 100 can identify the screen reference coordinates corresponding to the identified projector reference coordinates (S1440).

[0186] Electronic device 100 can acquire third brightness information corresponding to each of a plurality of virtual pixel regions based on first brightness information corresponding to the identified screen reference coordinates and second brightness information corresponding to the external projector device (S1450). According to an example, electronic device 100 can acquire third brightness information by adding the first brightness information of the first pixel corresponding to the identified screen reference coordinates and the second brightness information corresponding to the second pixel corresponding to the screen reference coordinates identified by the external projector device. According to an example, electronic device 100 can receive second brightness information from the external projector device.

[0187] The electronic device 100 can identify first brightness correction information corresponding to each of the plurality of pixels included in the first test image based on first brightness information and third brightness information (S1460). According to an example, the electronic device 100 can identify a first pixel region with the lowest brightness from among the plurality of virtual pixel regions based on the third brightness information, and identify a brightness compensation value corresponding to each of the plurality of virtual pixel regions based on fourth brightness information corresponding to the first pixel region and the first brightness information of each of the plurality of virtual pixel regions. According to an example, the electronic device 100 can identify first brightness correction information corresponding to each of the plurality of pixels included in the first test image based on the identified brightness compensation value.

[0188] According to an embodiment, the electronic device 100 can acquire second brightness correction information corresponding to each of the plurality of pixels included in the second test image based on the second brightness information and the third brightness information received from the external projector device, and send the acquired second brightness correction information to the external projector device.

[0189] exist Figure 14 For ease of description, the order of steps has been mapped, but this order is not necessarily restricted.

[0190] Figure 15 This is a diagram illustrating example methods for obtaining brightness correction information in a stacked configuration according to various embodiments.

[0191] refer to Figure 15 The electronic device 100 can identify the overlapping area 1530 of a first test image 1510 projected onto the screen according to keystone correction and a second test image 1520 projected onto the screen from an external projector device 200. For example, the projected image corresponding to the first test image 1510 projected by the electronic device 100 may be a first test image 1540, and the projected image corresponding to the second test image 1520 projected by the external projector device 200 may be a first test image 1550.

[0192] According to an embodiment, the electronic device 100 can identify the overlapping area 1530 on the screen as a plurality of virtual pixel areas. For example, the electronic device 100 can divide the virtual pixel areas included in the overlapping area 1530 into m horizontal grid areas and n vertical grid areas.

[0193] According to an embodiment, the electronic device 100 can identify projector reference coordinates corresponding to each of a plurality of virtual pixel regions, and identify screen reference coordinates corresponding to the identified projector reference coordinates. For example, the electronic device 100 can identify projector reference coordinates corresponding to the coordinates corresponding to the center point of each virtual pixel region, and identify screen reference coordinates corresponding to the identified projector reference coordinates. For example, the electronic device 100 can identify... Figure 15 The screen reference coordinates corresponding to the projector reference coordinates of the center point C of the first virtual pixel region 1531 in the image.

[0194] According to an embodiment, the electronic device 100 can identify first brightness correction information corresponding to each of a plurality of pixels based on first brightness information corresponding to the identified screen reference coordinates and second brightness information corresponding to the external projector device. For example, as described above, the electronic device 100 can identify a first brightness value relative to a screen reference pixel based on screen reference coordinates corresponding to a projector reference pixel. Additionally, the electronic device 100 can receive a second brightness value relative to a screen reference pixel from the external projector device 200. In this case, the external projector device 200 can calculate the second brightness value relative to the screen reference pixel using the same method as the electronic device 100.

[0195] According to an embodiment, the electronic device 100 can calculate the brightness value of each virtual pixel region by adding a first brightness value and a second brightness value corresponding to each virtual pixel region. For example, the electronic device 100 can calculate the brightness value from the (0,0) coordinate position to the (m,n) coordinate position in the virtual coordinate system grid.

[0196] According to an embodiment, electronic device 100 can identify a reference virtual pixel region from among the virtual pixel regions based on the brightness value of each virtual pixel region being calculated, and identify first brightness correction information corresponding to each virtual pixel region based on the brightness value (or area value) of the identified reference virtual pixel region. In this case, the first brightness correction information may be brightness correction information based on electronic device 100 in a stacked configuration. According to an example, electronic device 100 can identify the value obtained by dividing the brightness value of each virtual pixel region by the brightness value of the reference virtual pixel region as the first brightness correction information corresponding to each virtual pixel region. For example, electronic device 100 can determine the brightness correction ratio (or brightness adjustment gain) of each virtual pixel region based on "brightness value of each virtual pixel region / brightness value of the reference virtual pixel region".

[0197] According to an embodiment, the electronic device 100 can perform brightness correction by applying first brightness correction information corresponding to each virtual pixel region to a projector reference pixel corresponding to each virtual pixel region. For example, the electronic device 100 can store the first brightness correction information calculated for the projector reference pixel corresponding to each virtual pixel region in a memory 120. For example, the electronic device 100 can store the first brightness correction information in the memory 120 in the form of a lookup table (LUT), which includes a first brightness correction ratio (or brightness adjustment gain) corresponding to each pixel.

[0198] According to an embodiment, the electronic device 100 can correct the grayscale of an image based on first brightness correction information for each pixel stored in the memory 120 in a stacked configuration, thereby projecting an image with corrected grayscale. For example, based on the electronic device 100 projecting a specific image, the corrected grayscale value can be obtained by multiplying by a first brightness adjustment ratio corresponding to the grayscale value of each pixel forming the associated image, and the image including the corrected grayscale value can be projected onto a screen.

[0199] According to an embodiment, the electronic device 100 can calculate the second brightness correction information relative to the external projector device 200 in the same way as the first brightness correction information, and send the calculated second brightness correction information to the external projector device 200.

[0200] exist Figure 14 and Figure 15 In this context, electronic device 100 is described as calculating brightness correction information for electronic device 100 and external projector device 200 in a stacked configuration, but is not limited thereto. For example, brightness correction information for electronic device 100 and external projector device 200 can be calculated in a stacked configuration by receiving information required from another external device that communicates with electronic device 100 and external projector device 200.

[0201] Furthermore, while various embodiments describe calculating brightness correction information based on uniformly adjusting the brightness of the entire screen, according to embodiments, brightness correction information for each pixel can be calculated to give the central portion relatively higher brightness and the peripheral portion relatively lower brightness, thereby improving the average brightness of the entire screen. According to embodiments, brightness correction information for each pixel can be calculated to partially reduce the difference between bright and dark pixels.

[0202] Furthermore, while various embodiments describe calculating brightness correction information by calculating the screen width for each pixel, according to embodiments, brightness correction information can be calculated by sampling a portion of the pixels to calculate a screen reference width, and it can also be calculated by applying weight values ​​based on an interpolation method for pixels between the sampled pixels. In this case, the computational load for calculating brightness correction information can be reduced. For example, since the brightness of a pixel adjusted from a projector is ultimately proportional to the distance, the weight values ​​can be calculated by calculating the distance values.

[0203] Figure 16 This is a block diagram illustrating an example configuration of an electronic device according to various embodiments.

[0204] refer to Figure 16 The electronic device 100' may include an image projector 110, a memory 120, one or more processors (e.g., including processing circuitry) 130, a communication interface (e.g., including communication circuitry) 140, a user interface (e.g., including interface circuitry) 150, and a sensor 160.

[0205] The image projector 110 can expand or shrink the image based on the distance from the screen (projection distance). That is, it can perform a scaling function based on the distance from the screen. In this case, the scaling function can include hardware methods such as moving the lens and adjusting the screen size, as well as software methods such as cropping the image to adjust the screen size. When performing the scaling function, it is necessary to adjust the image's focus. For example, methods for adjusting the focus can include manual focusing, automatic focusing, etc.

[0206] The image projector 110 can provide zoom, keystone correction, or focus functions by automatically analyzing the surrounding environment and the projection environment without user input. Specifically, the projection unit can automatically provide zoom, keystone correction, or focus functions based on the distance between the electronic device 100 and the screen sensed by sensors (depth camera, distance sensor, infrared sensor, illuminance sensor, etc.), information about the current location of the electronic device 100, and information about the amount of ambient light.

[0207] At least one communication interface 140 (hereinafter referred to as the communication interface) can be implemented as a variety of interfaces including various communication circuits according to embodiments of electronic device 100'. For example, the communication interface 140 can communicate with external devices (e.g., user terminals), external storage media (e.g., USB memory), external servers (e.g., WEBHARD) via communication methods (e.g., but not limited to various types of digital interfaces, AP-based Wi-Fi (e.g., Wi-Fi, wireless LAN), Bluetooth, ZigBee, wired / wireless LAN, wide area network (WAN), Ethernet, IEEE 1394, high-definition multimedia interface (HDMI), universal serial bus (USB), mobile high-definition link (MHL), Audio Engineering Society / European Broadcasting Union (AES / EBU), fiber optic, coaxial cable, etc.).

[0208] User interface 150 can be implemented by a device including various interface circuits (e.g., buttons, touchpads, mice, and keyboards), or implemented as a touchscreen, remote control transceiver, etc., capable of performing the aforementioned display and operation input functions together. The remote control transceiver can receive remote control signals from an external remote control device, or transmit remote control signals via at least one of infrared communication, Bluetooth communication, or Wi-Fi communication.

[0209] Sensor 160 may include various types of sensors, such as, but not limited to, accelerometers, distance sensors, etc.

[0210] According to the implementation of electronic device 100', a speaker, tuner, and demodulator may be additionally included. The tuner (not shown) receives RF broadcast signals by tuning to a user-selected channel or all pre-stored channels among radio frequency (RF) broadcast signals received via an antenna. The demodulator (not shown) receives and demodulates the digital IF (DIF) signal converted from the tuner and performs channel decoding, etc. According to an embodiment, the input image received by the tuner, after being processed by the demodulator (not shown), can be provided to processor 130 for tone mapping according to embodiments of the present disclosure.

[0211] According to the various embodiments described above, the problem of screen brightness imbalance that occurs when keystone correction is performed from a projector device can be solved.

[0212] The methods according to the various embodiments of the present disclosure described above can be implemented as applications that can be installed in related electronic devices. The methods according to the various embodiments of the present disclosure described above can be performed using a deep learning-based artificial neural network (or a deep artificial neural network) (i.e., a trained network model).

[0213] Furthermore, the methods according to the various embodiments described above can be implemented simply by software or hardware upgrades of existing electronic devices.

[0214] Furthermore, the various embodiments described above can be executed by an embedded server configured in an electronic device or by an external server of the electronic device.

[0215] According to embodiments of this disclosure, the various embodiments described above can be implemented using software including instructions stored in a machine-readable storage medium (e.g., a computer). A machine can invoke the stored instructions from the storage medium and, as a device capable of operating according to the invoked instructions, can include an electronic device (e.g., electronic device (A)) according to the embodiments described above. Based on processor execution of the command, the processor can directly or under the control of the processor use other elements to perform a function associated with the command. The command may include code generated by a compiler or executed by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. In this document, a "non-transitory" storage medium is tangible and may not include signals, and the term does not distinguish whether data is semi-permanently or temporarily stored in the storage medium.

[0216] According to embodiments of this disclosure, methods according to the various embodiments described above can be provided in a computer program product. The computer program product can be exchanged as a commodity between a seller and a buyer. The computer program product can be distributed in the form of a machine-readable storage medium (e.g., a compact disk read-only memory (CD-ROM)) or through an app store (e.g., the Play Store). TM Online distribution. In the case of online distribution, at least a portion of the computer program product may be temporarily stored in a storage medium (e.g., the manufacturer's server, the app store's server, or the memory of a relay server), or may be temporarily generated.

[0217] Each element (e.g., module or program) according to the various embodiments described above may be formed as a single entity or multiple entities, and some of the aforementioned sub-elements may be omitted, or other sub-elements may be included in the various embodiments. Alternatively or additionally, a portion of the elements (e.g., module or program) may be integrated into one entity to perform the same or similar functions as the corresponding elements performed before integration. According to the various embodiments, operations performed by a module, program, or other element may be performed sequentially, in parallel, repeatedly, or heuristically, or at least some operations may be performed in a different order or omitted, or different operations may be added.

[0218] While this disclosure has been shown and described with reference to various exemplary embodiments, it should be understood that these exemplary embodiments are intended to be illustrative and not restrictive. Those skilled in the art will understand that various changes in form and detail may be made without departing from the true spirit and full scope of this disclosure (including the appended claims and their equivalents). It will also be understood that any embodiment described herein may be used in conjunction with any other embodiment described herein.

Claims

1. An electronic device comprising: Image projector; Memory, which stores one or more instructions; as well as At least one processor, including processing circuitry operatively connected to the image projector and the memory, Wherein, at least one processor is individually and / or collectively configured to execute the one or more instructions and is configured to: Keystone correction is performed by projecting the test image onto a screen; Based on the keystone correction, screen reference coordinates corresponding to each of the multiple pixels in the test image are identified; The screen reference area corresponding to each of the plurality of pixels is identified based on the identified screen reference coordinates. Based on the screen reference area corresponding to each of the plurality of pixels, a reference pixel is identified from the plurality of pixels; and Brightness correction information corresponding to each of the plurality of pixels is identified based on the screen reference area of ​​the identified reference pixel and the screen reference area of ​​each of the plurality of pixels.

2. The electronic device according to claim 1, wherein, At least one processor is configured individually and / or collectively as follows: The value obtained by dividing the screen reference area of ​​each of the plurality of pixels by the screen reference area of ​​the reference pixel is identified as the brightness correction information corresponding to each of the plurality of pixels.

3. The electronic device according to claim 1, wherein, At least one processor is configured individually and / or collectively as follows: The pixel corresponding to the largest area among the screen reference areas corresponding to each of the plurality of pixels is identified as the reference pixel.

4. The electronic device according to claim 1, wherein, The multiple screen reference coordinates corresponding to each of the multiple pixels include: The screen-based coordinates of four vertices corresponding to the four vertices of each of the plurality of pixels in the test image, and At least one processor is configured individually and / or collectively as follows: The screen area of ​​each of the plurality of pixels is calculated based on the four vertex coordinates of each of the plurality of pixels relative to the screen.

5. The electronic device according to claim 1, wherein, At least one processor is configured individually and / or collectively as follows: Identify the overlapping area of ​​a first test image projected onto the screen according to the keystone correction and a second test image projected onto the screen from an external projector device; The overlapping areas identified on the screen are identified as multiple virtual pixel regions; Identify the projector reference coordinates corresponding to each of the plurality of virtual pixel regions; Identify the screen reference coordinates corresponding to the identified projector reference coordinates; A third brightness information corresponding to each of the plurality of virtual pixel regions is obtained based on the first brightness information corresponding to the identified screen reference coordinates and the second brightness information corresponding to the external projector device. as well as First brightness correction information is identified based on the first brightness information and the third brightness information, corresponding to each of the plurality of pixels in the first test image.

6. The electronic device according to claim 5, wherein, At least one processor is configured individually and / or collectively as follows: The third brightness information is obtained by adding the first brightness information of the first pixel corresponding to the identified screen reference coordinates and the second brightness information corresponding to the second pixel corresponding to the screen reference coordinates identified by the external projector device.

7. The electronic device according to claim 5, wherein, At least one processor is configured individually and / or collectively as follows: Based on the third brightness information, the first pixel region with the lowest brightness is identified from the plurality of virtual pixel regions; A brightness compensation value corresponding to each of the plurality of virtual pixel regions is identified based on the fourth brightness information corresponding to the first pixel region and the first brightness information of each of the plurality of virtual pixel regions. as well as First brightness correction information is identified based on the identified brightness compensation value, corresponding to each of the plurality of pixels in the first test image.

8. The electronic device according to claim 5, wherein, The overlapping area of ​​the first test image and the second test image is the largest quadrilateral region identified within the overlapping area of ​​the first test image and the second test image based on the aspect ratio of the first test image and the second test image.

9. The electronic device according to claim 5, further comprising: Communication interface, including communication circuitry, In this configuration, at least one processor is individually and / or collectively configured as follows: The second brightness information is received from the external projector device via the communication interface; Based on the second brightness information and the third brightness information, second brightness correction information corresponding to each of the plurality of pixels in the second test image is obtained; and The acquired second brightness correction information is sent to the external projector device through the communication interface.

10. The electronic device according to claim 1, wherein, The test image includes multiple markers, and At least one processor is configured individually and / or collectively as follows: Based on first information indicating the positions of the plurality of marks in the test image and second information indicating the positions of the plurality of marks in the captured image obtained from an external device capturing the screen, third information indicating the vertex region positions of the test image in the captured image is obtained. The third information is corrected based on the orientation information of the external device; as well as The trapezoidal correction is performed based on the corrected third information.

11. A method for controlling an electronic device, the method comprising: Keystone correction is performed by projecting the test image onto a screen; Based on the keystone correction, screen reference coordinates corresponding to each of the multiple pixels in the test image are identified; The screen reference area corresponding to each of the plurality of pixels is identified based on the identified screen reference coordinates. A reference pixel is identified from the plurality of pixels based on the screen reference area corresponding to each of the plurality of pixels; as well as Brightness correction information corresponding to each of the plurality of pixels is identified based on the screen reference area of ​​the identified reference pixel and the screen reference area of ​​each of the plurality of pixels.

12. The method according to claim 11, wherein: Identifying the brightness correction information includes: The value obtained by dividing the screen reference area of ​​each of the plurality of pixels by the screen reference area of ​​the reference pixel is identified as the brightness correction information corresponding to each of the plurality of pixels.

13. The method according to claim 11, wherein: Identifying the reference pixel includes: The pixel corresponding to the largest area among the screen reference areas corresponding to each of the plurality of pixels is identified as the reference pixel.

14. The method of claim 11, wherein: The multiple screen reference coordinates corresponding to each of the multiple pixels include: The screen-based coordinates of the four vertices corresponding to the four vertices of each of the plurality of pixels in the test image, and Identifying the reference pixel includes: The screen area of ​​each of the plurality of pixels is calculated based on the four vertex coordinates of each of the plurality of pixels relative to the screen.

15. A non-transitory computer-readable recording medium storing computer instructions that, when executed individually and / or jointly by at least one processor of an electronic device, cause the electronic device to perform operations, the operations comprising: Keystone correction is performed by projecting the test image onto a screen; Based on the keystone correction, screen reference coordinates corresponding to each of the multiple pixels in the test image are identified; The screen reference area corresponding to each of the plurality of pixels is identified based on the identified screen reference coordinates. A reference pixel is identified from the plurality of pixels based on the screen reference area corresponding to each of the plurality of pixels; as well as Brightness correction information corresponding to each of the plurality of pixels is identified based on the screen reference area of ​​the identified reference pixel and the screen reference area of ​​each of the plurality of pixels.

Images