Projection device and operation method thereof

Abstract

A projection device and an operation method thereof are provided. The projection device comprises: a projector; a fisheye lens; a memory for storing one or more instructions; and at least one processor. One or more instructions are executed by the at least one processor individually or in combination so that the projection device calculates a plurality of reference positions on the basis of pixel coordinates of each of a plurality of pixels of a corrected image, refers to the pixel values of an input image corresponding to each of the calculated plurality of reference positions, so as to set a pixel value for each of the plurality of pixels of the corrected image, thereby generating a corrected image in which distortion of the input image to be projected onto a screen through the fisheye lens is corrected, and controls the projector such that the generated corrected image is projected onto the screen through the fisheye lens.

Description

Projection device and method of operation thereof

[0001] The present invention relates to a projection device including an ultra-wide-angle lens, a method of operating the projection device, and a recording medium.

[0002] Conventional video projector systems are designed to project two-dimensional images onto a single, flat screen. However, in recent years, the types of images played back through projector systems have diversified, and the environments in which these images are played back have also diversified. For example, a projector capable of 360-degree projection can be used to project images onto a screen. Projectors capable of 360-degree projection may include an ultra-wide-angle lens.

[0003] Meanwhile, when projecting images onto a screen through an ultra-wide-angle lens, the projected image can be significantly distorted. Therefore, the image output from the projector needs to be edited or corrected to minimize distortion.

[0004] A projection device according to one embodiment of the present disclosure includes a projector, a fish-eye lens, a memory storing one or more instructions, and at least one processor coupled to the memory and including a processing circuit.

[0005] According to one embodiment of the present disclosure, the one or more instructions are individually or in combination executed by the at least one processor, so that the projection device calculates a plurality of reference positions based on pixel coordinates of each of a plurality of pixels of the corrected image, and sets a pixel value of each of a plurality of pixels of the corrected image by referring to a pixel value of the input image corresponding to each of the calculated plurality of reference positions, thereby generating a corrected image that corrects distortion of the input image projected onto a screen through the fish-eye lens.

[0006] By executing the one or more instructions individually or in combination by the at least one processor according to one embodiment of the present disclosure, the projection device controls the projector to project the generated corrected image onto the screen through the fish-eye lens.

[0007] A method of operating a projection device according to one embodiment of the present disclosure includes the steps of: calculating a plurality of reference positions based on pixel coordinates of each of a plurality of pixels of a correction image, and setting a pixel value of each of a plurality of pixels of the correction image by referring to a pixel value of an input image corresponding to each of the calculated plurality of reference positions, thereby generating a correction image that corrects distortion of the input image projected onto a screen through a fish-eye lens; and controlling a projector to project the generated correction image onto the screen through the fish-eye lens.

[0008] According to one embodiment of the present disclosure, a computer-readable recording medium having recorded thereon a program for performing a method of operating a projection device for projecting an image on a computer is provided.

[0009] The present disclosure can be readily understood by the combination of the following detailed description and the accompanying drawings, wherein reference numerals refer to structural elements.

[0010] FIG. 1A and FIG. 1B are drawings showing an operation of a projection device according to one embodiment of the present disclosure to correct distortion.

[0011] FIG. 2A is a diagram showing pixel positions of an input image and a corrected image, and projection points of a projection screen according to one embodiment of the present disclosure.

[0012] FIG. 2b is a diagram showing an input image, a correction image, and a projection screen according to one embodiment of the present disclosure.

[0013] FIG. 3 is a block diagram showing the configuration of a projection device according to one embodiment of the present disclosure.

[0014] FIG. 4A is a flowchart illustrating a method for generating a correction image by a projection device according to one embodiment of the present disclosure.

[0015] FIG. 4b is a detailed flowchart illustrating a method for generating a correction image by a projection device according to one embodiment of the present disclosure.

[0016] FIGS. 5A and 5B are diagrams for explaining an operation of referencing pixels of an input image to generate a correction image according to one embodiment of the present disclosure.

[0017] FIG. 5c is a drawing for explaining the relationship between a reference position and a correction image according to one embodiment of the present disclosure.

[0018] FIG. 6 is a flowchart illustrating a method for generating a corrected image using a low-pass filter by a projection device according to one embodiment of the present disclosure.

[0019] FIG. 7a, FIG. 7b, and FIG. 7c are diagrams for explaining an operation of calculating a reference interval of an input image according to one embodiment of the present disclosure.

[0020] FIG. 8 is an example of low-pass filters applied to each region of an input image according to one embodiment of the present disclosure.

[0021] FIG. 9 is a flowchart illustrating an operation of a projection device according to one embodiment of the present disclosure to adjust the size of an effective pixel area of ​​a corrected image.

[0022] FIG. 10 is a diagram illustrating an operation of a projection device according to one embodiment of the present disclosure to adjust the size of an effective pixel area of ​​a corrected image according to a distance parameter.

[0023] FIG. 11 is a diagram illustrating an operation of determining the size of a projection screen and the size of a correction image according to positional relationship information between a projection device and a screen according to one embodiment of the present disclosure.

[0024] FIG. 12 is a drawing for explaining an operation of a projection device according to one embodiment of the present disclosure to project an image onto a multi-screen.

[0025] FIG. 13 is an example of a multi-faceted input image and a multi-faceted corrected image according to one embodiment of the present disclosure.

[0026] FIG. 14 is a diagram illustrating a graphical user interface for adjusting a correction image according to one embodiment of the present disclosure.

[0027] FIG. 15 is a detailed configuration diagram of a projection device according to one embodiment of the present disclosure.

[0028] In this disclosure, the expression “at least one of a, b or c” may refer to “a”, “b”, “c”, “a and b”, “a and c”, “b and c”, “all of a, b and c”, or variations thereof.

[0029] Below, embodiments of the present disclosure are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein.

[0030] The terms used in this disclosure are described as currently common terms, taking into account the functions mentioned herein. However, these terms may mean various other terms depending on the intentions of those skilled in the art, precedents, the emergence of new technologies, etc. Therefore, the terms used in this disclosure should not be interpreted solely based on their names, but rather based on the meanings of the terms and the overall content of this disclosure.

[0031] Additionally, the terminology used in this disclosure is for the purpose of describing specific embodiments only and is not intended to limit the present disclosure.

[0032] Throughout the specification, when a part is said to be "connected" to another part, this includes not only the cases where it is "directly connected" but also the cases where it is "electrically connected" with another element in between.

[0033] As used herein, and particularly in the claims, the terms "above" and "above" and similar referents may refer to both the singular and the plural. Furthermore, unless the order of steps in a method according to the present disclosure is explicitly specified, the steps described may be performed in any appropriate order. The present disclosure is not limited by the order in which the steps are described.

[0034] The appearances of phrases such as “in some embodiments” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment.

[0035] Some embodiments of the present disclosure may be represented by functional block configurations and various processing steps. Some or all of these functional blocks may be implemented by various hardware and / or software configurations that perform specific functions. For example, the functional blocks of the present disclosure may be implemented by one or more microprocessors or by circuit configurations for a given function. Furthermore, for example, the functional blocks of the present disclosure may be implemented in various programming or scripting languages. The functional blocks may be implemented by algorithms that execute on one or more processors. Furthermore, the present disclosure may employ conventional techniques for electronic configuration, signal processing, and / or data processing. Terms such as “mechanism,” “element,” “means,” and “configuration” may be used broadly and are not limited to mechanical and physical configurations.

[0036] Additionally, the connecting lines or connecting members between components depicted in the drawings are merely exemplary representations of functional connections and / or physical or circuit connections. In an actual device, connections between components may be represented by various functional connections, physical connections, or circuit connections that may be replaced or added.

[0037] Additionally, terms such as “part”, “module”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software, or a combination of hardware and software.

[0038] In the present disclosure, a processor may include various processing circuits and / or multiple processors. For example, the term “processor” as used herein, including in the claims, may include various processing circuits, including at least one processor. At least one processor, one or more processors may be configured to perform various functions described herein, individually and / or collectively, in a distributed fashion. As used herein, “processor,” “at least one processor,” and “one or more processors” may be configured to perform various functions. However, these terms encompass, without limitation, situations where one processor performs some of the functions and other processor(s) perform other parts of the functions, and situations where a single processor may perform all of the functions. Furthermore, the at least one processor may include a combination of processors that perform various functions of the disclosed functions in a distributed manner. At least one processor may execute program instructions to achieve or perform various functions.

[0039] Additionally, the term "user" in this specification refers to a person who utilizes the projection device, and may include a consumer, evaluator, viewer, administrator, or installer. Furthermore, the term "manufacturer" or "provider" in this specification may refer to a manufacturer that manufactures the projection device and / or components included in the projection device.

[0040] In the present disclosure, an 'image' may include a still image, a graphic, a picture, a frame, a moving image composed of a plurality of consecutive still images, or a video.

[0041] FIG. 1A and FIG. 1B are drawings showing an operation of a projection device according to one embodiment of the present disclosure to correct distortion.

[0042] Referring to FIGS. 1A and 1B, a projection device (100) according to one embodiment may include a projector (130) and a fisheye lens (140).

[0043] A projection device (100) according to one embodiment can project an image. For example, the projection device (100) can project in a 360-degree direction. For example, the projection device (100) can project an image onto a screen. The screen or space onto which the image is projected can be configured in various shapes. For example, the screen or space onto which the image is projected can be configured in a single-screen, multi-screen, dome-shaped, hemispherical, etc. The projection device (100) can project an image onto a screen (50) via a fish-eye lens (140).

[0044] The projector (130) may include a light source that generates light, a lens, etc. The projector (130) may perform projection by driving the light source or adjusting the direction, position, angle, etc. of the projection.

[0045] The fisheye lens (140) may be an ultra-wide-angle lens having a wider angle of view than a normal lens. For example, the angle of view of the fisheye lens (140) may be 180 degrees or more. The projection device (100) may project an image onto the entire screen, which may be configured in a cross-sectional, multi-faceted, dome-shaped, or hemispherical shape, through the fisheye lens (140). Due to the characteristics of the fisheye lens (140), the image projected through the fisheye lens (140) has radial distortion.

[0046] For example, as illustrated in FIG. 1A, when a projection device (100) according to one embodiment projects an input image (10) onto a screen (50) through a fish-eye lens (140), pincushion distortion may occur in the image (20) displayed on the screen (50). Pincushion distortion has a shape in which the central area of ​​the image appears reduced and the peripheral area of ​​the image appears enlarged.

[0047] According to one embodiment, when an input image (10) is transmitted through a fish-eye lens (140), the input image (10) has the same size for each area, but in the image (20) displayed on the screen (50), the outer area may be projected larger than the center area.

[0048] Referring to FIG. 1b, a projection device (100) according to one embodiment can correct pincushion distortion by using a correction image corresponding to reverse deformation of pincushion distortion.

[0049] For example, a projection device (100) according to one embodiment can generate a corrected image (30) having barrel distortion corresponding to the inverse deformation of pincushion distortion from an input image (10). Barrel distortion has a shape in which the central area of ​​the image appears enlarged and the peripheral area of ​​the image appears reduced.

[0050] A projection device (100) according to one embodiment can project a corrected image (30) corresponding to the reverse deformation of pincushion distortion onto a screen (50). The corrected image (30) corresponding to the reverse deformation of pincushion distortion can be distorted through a fisheye lens (140). Since the corrected image (30) has a shape corresponding to the reverse deformation of pincushion distortion, it can be projected onto the screen (50) again in the same shape as the input image (10) as it is distorted through the fisheye lens (140). Pincushion distortion may not occur in the image (40) displayed on the screen (50).

[0051] According to one embodiment, a projection device (100) can generate a corrected image (30) by correcting pixel values ​​so that the size of the central region of an input image (10) increases and the size of the peripheral region decreases. When the corrected image (30) is transmitted through a fish-eye lens (140), the central region and the peripheral region can be shown to have the same size in the image (40) displayed on the screen (50). By projecting the corrected image (30), the projection device (100) can prevent image distortion caused by the fish-eye lens (140).

[0052] Hereinafter, a specific method for generating a correction image by referring to an input image by a projection device (100) according to one embodiment will be described in detail with reference to drawings.

[0053] FIG. 2a is a diagram showing pixel positions of an input image and a corrected image, and projection points of a projection screen, according to one embodiment of the present disclosure. FIG. 2b is a diagram showing an input image, a corrected image, and a projection screen, according to one embodiment of the present disclosure.

[0054] FIG. 2a illustrates a plurality of pixels constituting an input image (210), a plurality of pixels constituting a correction image (220), and a plurality of projection points constituting a projection screen (230). FIG. 2b illustrates an image in which pixel values ​​are written to each of a plurality of pixels and an image displayed on a screen (50). Each of the input image (210), the correction image (220), and the projection screen (230) may correspond to the input image (10), the correction image (30), and the image (40) displayed on the screen (50) of FIG. 1b.

[0055] Referring to FIG. 2a, for example, assuming that the input image (210) has 1920x1080 pixels and the center coordinate of the input image (210) is (0,0), the coordinate range of the input image (210) may be x=[-960 to +959], y=[-540 to +539]. The interval between multiple pixels belonging to the input image (210) (hereinafter, pixel interval) may be constant.

[0056] Since the corrected image (220) is an image corrected from the input image (210), it may have the same number of pixels as the input image (210). For example, assuming that the corrected image (220) has 1920x1080 pixels and the center coordinate of the corrected image (220) is (0,0), the coordinate range of the corrected image (220) may be u=[-960 to +959], v=[-540 to +539]. The pixel spacing of the corrected image (220) may be constant.

[0057] When an image is projected onto a screen through a fish-eye lens, the coordinates of the projection point belonging to the projection screen (230) can be calculated using mathematical expression 1.

[0058] [Mathematical Formula 1]

[0059]

[0060] Here, [mn] represents the projection point coordinates after passing through the fisheye lens, and [uv] represents the pixel coordinates of the image. represents the distance from the center coordinate, and L may represent the distance between the projection device (100) and the screen. may be a preset value according to the specifications of the fisheye lens. For example, the center coordinate of the image may be assumed to be (0, 0).

[0061] Here, the image is exemplified as the coordinates (u, v) of the corrected image (220), but may also be the coordinates (x, y) of the input image (210).

[0062] When projecting an image onto a screen through a fisheye lens, the spacing between projection points (hereinafter, projection spacing) on ​​the projection screen (230) may vary depending on the area. For example, the projection spacing in the outer area may be wider than the projection spacing in the center area of ​​the projection screen (230). In this case, while the pixel spacing in the image is constant, the outer area is projected larger than the center area on the projection screen (230). Here, the image may be an input image (210) or a corrected image (220).

[0063] Meanwhile, the size of the projection screen (230) and the spacing between projection points can be adjusted based on the distance (L) between the projection device (100) and the screen.

[0064] Referring to FIG. 2b, in the case of the input image (210), the size of the central region (11) and the size of the outer region (12) may be the same. Since the input image (210) has the same size in the central region (11) and the outer region (12), when the input image (210) is projected through a fish-eye lens, the outer region may appear larger than the central region on the projection screen (see 20 in FIG. 1a).

[0065] According to one embodiment, the projection device (100) can correct pixel values ​​so that the size of the central region of the input image (210) increases and the size of the peripheral region decreases. The corrected image (220) according to one embodiment can be an image in which pixel values ​​are corrected from the input image (210) so that the size of the central region increases and the size of the peripheral region decreases. Accordingly, in the case of the corrected image (220), the size of the central region (31) and the size of the peripheral region (32) may be different. For example, the size of the central region (31) of the corrected image (220) may be larger than the size of the peripheral region (32).

[0066] When the corrected image (220) is projected through a fish-eye lens, the central area and the peripheral area on the projection screen (230) can be shown as having the same size. The projection screen (230) can be shown as an image without distortion, similar to the input image (210).

[0067] More specifically, the projection device (100) according to one embodiment can generate a correction image (220) including a first area (221) having a barrel distortion shape using pixel values ​​of an input image (210). The correction image (220) can further include a second area (222) surrounding the first area (221). The first area (221) of the correction image (220) is generated by referring to the pixel values ​​of the input image (210) and may be referred to as a valid pixel area. The second area (222) of the correction image (220) is generated by using a preset value (e.g., black) without referring to the pixel values ​​of the input image (210) and may be referred to as a black area.

[0068] When the corrected image (220) is projected through a fish-eye lens, the projection screen (230) may have a first area (231) corresponding to the first area (221) of the corrected image (220) and a second area (232) corresponding to the second area (222) of the corrected image (220). The first area (231) may be an area where pixel values ​​of the input image exist, and the second area (232) may be an area where pixel values ​​of the input image do not exist. The first area (231) of the projection screen (230) may be displayed as an image without distortion, similar to the input image (210).

[0069] FIG. 3 is a block diagram showing the configuration of a projection device according to one embodiment of the present disclosure.

[0070] Referring to FIG. 3, a projection device (100) according to one embodiment may include a processor (110), a memory (120), a projector (130), and a fish-eye lens (140).

[0071] The processor (110) controls the overall operation of the projection device (100) and the signal flow between internal components of the projection device (100), and performs the function of processing data.

[0072] The processor (110) may include at least one of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a VPU (Video Processing Unit). Alternatively, according to an embodiment, the processor may be implemented in the form of a SoC (System On Chip) that integrates at least one of a CPU, a GPU, and a VPU. Alternatively, the processor (110) may further include an NPU (Neural Processing Unit). The processor (110) may include single cores, dual cores, triple cores, quad cores, and multiples thereof. In addition, the processor (110) may include at least one processor.

[0073] The memory (120) can store various data, programs or applications for driving and controlling the projection device (100).

[0074] Additionally, the program stored in the memory (120) may include one or more instructions. The program (one or more instructions) or application stored in the memory (120) may be executed by the processor (110).

[0075] According to one embodiment, a processor (110) can generate a corrected image that corrects distortion of an input image projected onto a screen through a fish-eye lens (140) by executing one or more instructions stored in a memory (120).

[0076] A processor (110) according to one embodiment can generate a correction image by referencing pixel values ​​of an input image using a reference position. The reference position can correspond to a projection position of a pixel predicted when an image with a constant pixel spacing is projected onto a screen through a fish-eye lens (140). A processor (110) according to one embodiment can generate a correction image corresponding to an inverse transformation of projection distortion through a reference position corresponding to a predicted projection position when a correction image is projected.

[0077] A reference position according to one embodiment may correspond to a pixel coordinate of an input image for referencing a pixel value of the input image. The processor (110) according to one embodiment may set a pixel value of a pixel of the input image having a coordinate corresponding to the reference position as a pixel value of the corrected image.

[0078] A processor (110) according to one embodiment can calculate a reference position through mathematical expression 2 similar to mathematical expression 1 described above.

[0079] [Equation 2]

[0080]

[0081] Here, [xy] represents the reference position corresponding to the pixel coordinates of the input image, and [uv] represents the pixel coordinates of the corrected image. represents the distance from the center coordinate, represents the specifications of the fisheye lens, and d can represent a distance parameter. The interval between reference positions (reference interval) can be adjusted based on the distance parameter.

[0082] According to one embodiment, the processor (110) may calculate a reference position based on at least one of pixel coordinates of the corrected image, a distance parameter, a specification of the fish-eye lens (140), and a distance between the center coordinates of the corrected image and the pixel coordinates of the corrected image. For example, FIG. 5A illustrates a reference image (515) showing pixels of an input image (210), pixels of a corrected image (220), and a reference position.

[0083] According to one embodiment, the calculated reference position spacing (reference spacing) may correspond to the spacing between projection points as pixels of the corrected image pass through the fish-eye lens (140). For example, the reference spacing may be narrow in the central region and wide in the peripheral region.

[0084] According to one embodiment, the processor (110) may obtain pixel values ​​of a corrected image by referring to pixel values ​​of an input image corresponding to a reference position. For example, the processor (110) may set pixel values ​​of an input image to pixel values ​​of a corrected image through mathematical expression 3.

[0085] [Equation 3]

[0086]

[0087] Here, O may represent a pixel value of the corrected image, and I may represent a pixel value of the input image. The pixel value of the input image may be a value previously stored in the memory (120).

[0088] According to one embodiment, the processor (110) can draw a corrected image using pixel values ​​of an input image previously stored in a memory (120). Here, drawing a corrected image may mean writing pixel values ​​for each pixel of the corrected image using pixel values ​​of the input image.

[0089] According to one embodiment, the processor (110) can read pixel values ​​of an input image corresponding to reference locations for each pixel coordinate of the corrected image. The processor (110) can draw the corrected image on the memory (120) using the pixel values ​​read from the input image. Here, drawing the corrected image on the memory (120) can mean writing pixel values ​​for each pixel of the corrected image.

[0090] For example, the processor (110) can identify the pixel coordinates of the input image located at the calculated reference location (x, y) for each pixel coordinate (u, v) of the corrected image, and read the pixel values ​​of the input image. The processor (110) can write the pixel values ​​read from the input image to the pixels of the corrected image.

[0091] According to one embodiment, a processor (110) can generate a corrected image including a first area (valid pixel area) in which pixel values ​​of an input image are reflected and a second area (black area) in which pixel values ​​of the input image are not reflected.

[0092] According to one embodiment, the processor (110) can identify whether the reference position calculated from the pixel coordinates of the corrected image is within the coordinate range of the input image through mathematical expression 2. If the reference position is within the coordinate range of the input image, the processor (110) can set the pixel value of the input image to the pixel value of the corrected image as in mathematical expression 3. For example, if a pixel of the input image exists at the reference position (x, y) calculated from the pixel coordinates (u, v) of the corrected image, the processor (110) can set the pixel value of the corresponding pixel to the pixel value of the corrected image. The processor (110) can generate a first region in which the pixel value of the input image is entered.

[0093] According to one embodiment, the processor (110) may set a predetermined color value as a pixel value of the corrected image when a reference position calculated from the pixel coordinates of the corrected image through mathematical expression 2 is outside the coordinate range of the input image. For example, the predetermined color value may be black with R, G, and B color values ​​of (0, 0, 0), but is not limited thereto. For example, when a pixel of the input image does not exist at the reference position (x, y) calculated from the pixel coordinates (u, v) of the corrected image, the pixel value of the corrected image may be set to black. The processor (110) may generate a second area in which a predetermined color value is written, but in which a pixel value of the input image is not written.

[0094] According to one embodiment, a corrected image may have pixel values ​​that are barrel-distorted from the pixel values ​​of an input image. A first region of the corrected image may have a barrel-distorted shape corresponding to the inverse transformation of the projection distortion of the input image. A second region may be an area where pixels of the input image do not exist, and may be located around the first region.

[0095] In one embodiment, the processor (110) can predict projection distortion (pin cushion distortion) through a reference position and generate a corrected image (barrel distortion) in which the projection distortion is reversed. For example, the processor (110) can predict projection distortion in which the central region of the image becomes narrower and the peripheral region becomes wider, and generate a corrected image in which the central region of the image becomes wider and the peripheral region becomes narrower so that the projection distortion is reversed. The corrected image in one embodiment can be an image in which pixel values ​​are corrected from an input image so that the central region of the input image becomes larger and the peripheral region becomes smaller. When the corrected image is projected through a fisheye lens (140), the sizes of the central region and the peripheral region become the same, so that it can be displayed in the same appearance as the input image on the projection screen.

[0096] Meanwhile, when the processor (110) according to one embodiment generates a corrected image in which the central region is enlarged and the peripheral region is reduced from an input image with a constant central region and peripheral region, downscaling (or image reduction) may be performed on the peripheral region. As downscaling is performed, an aliasing phenomenon may occur in the peripheral region. The aliasing phenomenon is a phenomenon in which details are distorted when an image with fine details is excessively reduced.

[0097] According to one embodiment, a processor (110) can downscale an image using a low-pass filter. By using a low-pass filter, the processor (110) can prevent aliasing.

[0098] According to one embodiment, the processor (110) may apply different low-pass filters according to the size of the image, which varies from region to region, when generating a corrected image from an input image. The processor (110) may generate a corrected image by applying different low-pass filters to each region of the input image. The processor (110) may determine the low-pass filter to be applied to each region using reference positions. For example, the processor (110) may apply a strong or weak low-pass filter by identifying whether the interval between reference positions (reference interval) is narrow or wide. Accordingly, the processor (110) may effectively prevent aliasing. This will be further described in FIG. 6.

[0099] According to one embodiment, the processor (110) can adjust the size of the first region of the corrected image according to the distance parameter. For example, according to Equation 2, the reference interval varies depending on the distance parameter, and the size of the first region of the corrected image can vary depending on the reference interval. For example, as the distance parameter increases, the first region of the corrected image can become smaller, and as the distance parameter decreases, the first region of the corrected image can become larger. The processor (110) can generate a corrected image in which the first region is enlarged or reduced by adjusting the distance parameter. This will be further described with reference to FIG. 9.

[0100] According to one embodiment, a processor (110) can adjust a distance parameter based on positional relationship information between a projection device (100) and a screen. The positional relationship information can include distance information, angle information, etc. between the projection device (100) and the screen.

[0101] For example, as the distance between the projection device (100) and the screen increases, the projection screen becomes larger, and the first area within the projection screen may become larger. The processor (110) according to one embodiment may adjust the distance parameter to maintain the size of the first area constant even if the distance between the projection device (100) and the screen changes. The processor (110) may adjust the distance parameter based on positional relationship information between the projection device (100) and the screen, thereby displaying the size of the first area constant even if the distance between the projection device (100) and the screen increases or decreases. For example, the processor (110) may increase the distance parameter so that the size of the first area of ​​the corrected image decreases as the distance between the projection device (100) and the screen increases. This will be further described with reference to FIG. 10.

[0102] According to an embodiment, the processor (110) may determine, through the reference position, the pixel values ​​of the corrected image, the type of low-pass filter to be used, the size (object size) of the first region of the corrected image, etc. For example, the processor (110) may obtain, through the reference position, the pixel values ​​of the input image to be read as the pixel values ​​of the corrected image. For example, the processor (110) may determine, through the reference position, the degree to which the image is narrowed or widened for each region when generating the corrected image, and determine the low-pass filter to be applied to the input image. For example, the processor (110) may determine, through the reference position, the sizes of the first region and the second region of the corrected image. According to an embodiment, the processor (110) may control the projector (130) to project the generated corrected image onto a screen.

[0103] A projector (130) according to one embodiment may include a light source that generates light, a lens, etc. In addition, the projector (130) may further include a driving unit that adjusts the direction, position, angle, etc. of projection. The projector (130) may project a 360-degree image by driving the light source or adjusting the direction, position, angle, etc. of projection according to a control signal received from the processor (110).

[0104] A fisheye lens (140) according to one embodiment may be an ultra-wide-angle lens having a wider angle of view than a typical lens. A description of the fisheye lens (140) is omitted as it has been described in FIGS. 1A and 1B.

[0105] FIG. 4A is a flowchart illustrating a method for generating a correction image by a projection device according to an embodiment of the present disclosure. FIG. 4B is a detailed flowchart illustrating a method for generating a correction image by a projection device according to an embodiment of the present disclosure. FIGS. 5A and 5B are diagrams for explaining an operation of referencing pixels of an input image to generate a correction image according to an embodiment of the present disclosure. FIGS. 4A and 4B are explained in conjunction with FIGS. 5A and 5B.

[0106] Referring to FIG. 4A, in operation 405, the projection device (100) according to one embodiment can generate a correction image (220) that corrects distortion of an input image projected onto a screen through a fish-eye lens (140). The projection device (100) according to one embodiment can generate the correction image (220) by performing operations 410 and 420.

[0107] In operation 410, the projection device (100) according to one embodiment can calculate a reference position corresponding to the pixel coordinates of the input image (210) based on the pixel coordinates of the corrected image (220).

[0108] A projection device (100) according to one embodiment can calculate a reference position of an input image (210) corresponding to a predicted projection position of a pixel when a corrected image is projected onto a screen through a fish-eye lens (140). For example, the projection device (100) can calculate the reference position from the pixel coordinates of the corrected image (220) through mathematical expression 2.

[0109] The pixel spacing between the input image (210) and the corrected image (220) may be constant. For example, the pixel spacing of the corrected image (220) may be the same in the central region (503) and the peripheral region (504). In the reference image (515) in which the reference position is indicated, the reference spacing may differ for each region in accordance with the projection position. For example, the reference spacing may be narrow in the central region (501) and wide in the peripheral region (502).

[0110] For example, the projection device (100) can calculate a reference position corresponding to each pixel by moving a plurality of pixels belonging to the corrected image (220) one pixel at a time. For example, if the corrected image (220) has 1920x1080 pixels and the center coordinate is (0,0), the coordinate range of the corrected image (220) may be u=[-960 to +959], v=[-540 to +539]. The projection device (100) can calculate the reference position (x, y) by applying the coordinates of (u, v)=(-960, -540) to (+959, +539) to mathematical expression 2.

[0111] In operation 420, the projection device (100) according to one embodiment can obtain pixel values ​​of a correction image (220) by referring to pixel values ​​of an input image (210) corresponding to a reference position.

[0112] According to one embodiment, the projection device (100) can read the pixel values ​​of the input image (210) corresponding to the reference positions calculated for each pixel coordinate of the corrected image (220). For example, the projection device (100) can obtain the pixel values ​​of the corrected image (220) through mathematical expression 3.

[0113] A projection device (100) according to one embodiment can write pixel values ​​for each pixel constituting a corrected image (220) into memory using pixel values ​​read from an input image (210).

[0114] A projection device (100) according to one embodiment can generate a corrected image (220) including a first area (221) in which pixel values ​​of an input image (210) are reflected and a second area (222) in which pixel values ​​of the input image (210) are not reflected. This will be further described with reference to FIG. 4b.

[0115] Referring to FIG. 4b, in operation 421, the projection device (100) according to one embodiment can identify whether the reference position calculated from the pixel coordinates of the corrected image (220) is within the coordinate range (520) of the input image.

[0116] In operation 422, the projection device (100) according to one embodiment may set the pixel values ​​of the input image to the pixel values ​​of the corrected image as in Equation 3 when the reference position is within the coordinate range (520) of the input image. In operation 423, the projection device (100) may generate a first area (221) of the corrected image (220).

[0117] For example, if (u, v) = (0, 0), (x, y) = (0, 0) can be calculated. In this case, the reference position exists within the coordinate range x = [-960 ~ +959], y = [-540 ~ +539] of the input image (210). The projection device (100) can set the pixel value of the pixel of the input image (210) existing at the (0, 0) position to the pixel value of the corrected image (220).

[0118] In operation 424, the projection device (100) according to one embodiment may set a predetermined color value as a pixel value of the corrected image if the reference position is outside the coordinate range (520) of the input image. For example, the reference position may be located in an external area (530) where no pixel value of the input image (210) exists. In operation 425, the projection device (100) may create a second area (222).

[0119] For example, if (u, v) = (-960, -540), it can be assumed that (x, y) = (-900, -700). In this case, since the reference position is outside the coordinate range x = [-960 ~ +959], y = [-540 ~ +539] of the input image (210), there may not be a pixel of the input image (210) to be referenced. The projection device (100) can set the pixel value of the pixel existing at the position (-960, -540) of the corrected image (220) to black.

[0120] According to one embodiment, a corrected image (220) may have pixel values ​​that are barrel-distorted from the pixel values ​​of an input image (210). A first region (221) of the corrected image (220) may have a barrel-distorted shape corresponding to the inverse transformation of the projection distortion of the input image (210). A second region (222) corresponds to an external region (530) where pixels of the input region (210) do not exist, and may be located around the first region (221).

[0121] Referring again to FIG. 4A, at operation 430, the projection device (100) according to one embodiment may control the projector to project the generated corrected image (220) onto a screen.

[0122] A projection device (100) according to one embodiment can prevent image distortion caused by a fish-eye lens (140) by outputting a correction image (220). The projection device (100) can project a correction image (220) including a first region (221) in which a central region is widened and an outer region is narrowed from an input image (210).

[0123] The corrected image (220) projected through the fisheye lens (140) can be displayed on the projection screen in the same manner as the input image (210). For example, the projection screen on which the corrected image (220) is projected can correspond to the projection screen (230) of FIG. 2B.

[0124] FIG. 5C is a diagram illustrating the relationship between a reference position and a correction image according to one embodiment of the present disclosure. FIG. 5C illustrates a central region (501) and an outer region (502) of a reference image (515), and a central region (503) and an outer region (504) of a correction image (220).

[0125] When a projection device (100) according to one embodiment generates a corrected image (220) from an input image (210) having a constant center region and an outer region, the center region may become larger and the outer region may become smaller. In other words, image enlargement may be performed in the center region and image reduction may be performed in the outer region. In order to prevent aliasing that occurs as the image is reduced (downscaled), the projection device (100) may apply a low-pass filter to the input image.

[0126] According to one embodiment, when generating a corrected image (220) from an input image (210), a projection device (100) can apply different low-frequency filters to the input image (210) according to the degree to which the size of the image increases or decreases in each area.

[0127] According to one embodiment, the projection device (100) can identify whether the corrected image (220) is enlarged or reduced from the input image (210) by using a reference position. For example, the projection device (100) can identify whether the image is enlarged or reduced by area by using the degree to which the reference interval is narrow or wide by area. For example, in an area with a narrow reference interval, an operation of generating a corrected image from the input image may correspond to image enlargement, and in an area with a wide reference interval, an operation of generating a corrected image from the input image may correspond to image reduction.

[0128] For example, in the reference image (515), the reference interval in the central region (501) may be narrow, and the reference interval in the outer region (502) may be wide.

[0129] The projection device (100) can generate a corrected image (220) having an enlarged central area (503) from a central area (501) with a narrow reference interval (image enlargement).

[0130] The projection device (100) can generate a corrected image (220) having a reduced outer region (504) from an outer region (502) with a wide reference interval (image reduction).

[0131] According to one embodiment, the projection device (100) can determine a low-pass filter to be applied to each region using a reference position. For example, the projection device (100) can use a weak low-pass filter corresponding to a central region (501) with a narrow reference interval. The projection device (100) can use a strong low-pass filter corresponding to an outer region (502) with a wide reference interval. Here, the strong low-pass filter may refer to a low-pass filter with a low transmission frequency. The lower the transmission frequency, the more high-frequency components can be removed. The lower the transmission frequency, the more effective the anti-aliasing can be.

[0132] For example, the projection device (100) may use a strong low-pass filter in an outer region (502) where image reduction is large. The projection device (100) may use the strong low-pass filter when generating an outer region (504) of a corrected image (220) using pixels in the outer region (502) where image reduction is performed.

[0133] For example, the projection device (100) may use a weak low-pass filter in a central region (501) where image reduction is minimal. The projection device (100) may use the weak low-pass filter when generating a central region (503) of a corrected image (220) using pixels in the central region (501) where image enlargement is performed.

[0134] Below, the operation of calculating the reference interval and using the low-frequency filter differently for each area is further explained in Fig. 6.

[0135] FIG. 6 is a flowchart illustrating a method for generating a corrected image using a low-pass filter by a projection device according to one embodiment of the present disclosure.

[0136] Referring to FIG. 6, in operation 610, the projection device (100) according to one embodiment may calculate an interval between a first reference position corresponding to a first pixel of a corrected image and a second reference position corresponding to a second pixel of the corrected image. The first pixel and the second pixel may be adjacent pixels. The first reference position may be a position calculated by substituting the first pixel coordinates into mathematical expression 2. The second reference position may be a position calculated by substituting the second pixel coordinates into mathematical expression 2.

[0137] A projection device (100) according to one embodiment can calculate an interval between reference positions using a first direction line segment length connecting a first reference position and a second reference position. For example, the projection device (100) can calculate the first direction line segment length as an interval between reference positions (Fig. 7a).

[0138] According to one embodiment, a projection device (100) can calculate an interval between reference positions using an orthogonal distance between a first reference position and a second reference position. For example, the projection device (100) can calculate a vertical distance and / or a horizontal distance between the first reference position and the second reference position as an interval between the reference positions (Fig. 7b).

[0139] A projection device (100) according to one embodiment may consider a distance from at least one reference position based on a first reference position. For example, the projection device (100) may calculate a reference distance by considering a distance from an adjacent reference position based on the first reference position. Alternatively, for example, the projection device (100) may calculate a reference distance by considering a distance from eight adjacent reference positions based on the first reference position (Fig. 7c).

[0140] In operation 620, the projection device (100) according to one embodiment can determine a low-pass filter based on a distance between a first reference position and a second reference position.

[0141] According to one embodiment, a projection device (100) can apply a first low-pass filter to an input image when a gap between a first reference position and a second reference position is greater than or equal to a threshold value.

[0142] According to one embodiment, the projection device (100) can apply a second low-pass filter when the distance between the first reference position and the second reference position is less than a threshold value.

[0143] The first low-pass filter may have a lower pass-through frequency than the second low-pass filter. A lower pass-through frequency means that more high-frequency components are removed, indicating a strong low-pass filter. The first low-pass filter may be referred to as a "strong low-pass filter," and the second low-pass filter may be referred to as a "weak low-pass filter."

[0144] In operation 630, the projection device (100) according to one embodiment can calculate a first pixel value of a corrected image by applying a low-pass filter to an input image.

[0145] According to one embodiment, the projection device (100) may have a large reduction in image size when generating a correction image in an area with a large reference interval. Accordingly, the projection device (100) may calculate pixel values ​​of the correction image by applying a strong low-pass filter to pixels in the area. The area with a large reference interval (i.e., the area with a large reduction in image size) may correspond to an outer region of the input image.

[0146] According to one embodiment, the projection device (100) may have less image reduction due to generating a correction image in an area with a small reference interval. Accordingly, the projection device (100) may calculate pixel values ​​by applying a weak low-pass filter to pixels in the area. The area with a small reference interval (i.e., an area with less image reduction) may correspond to the central area of ​​the input image.

[0147] A projection device (100) according to one embodiment can calculate pixel values ​​of a corrected image by applying different low-pass filters to each region of an input image. The projection device (100) can generate a corrected image in which aliasing is effectively prevented based on the pixel values ​​obtained by applying the low-pass filter to each region.

[0148] FIG. 7a, FIG. 7b, and FIG. 7c are diagrams for explaining an operation of calculating a reference interval of an input image according to one embodiment of the present disclosure.

[0149] In FIGS. 7A, 7B, and 7C, a reference image (710) and a correction image (720) composed of reference positions of an input image are illustrated. Pixel values ​​of the correction image (720) may be sequentially set. A first pixel may correspond to a current pixel, a second pixel may correspond to a left pixel, and a third pixel may correspond to an upper pixel. The first reference position may correspond to a current reference position, the second reference position may correspond to a left reference position, and the third reference position may correspond to an upper reference position. The first reference interval may correspond to a distance between the first reference position and the second reference position. The second reference interval may correspond to a distance between the first reference position and the third reference position.

[0150] According to one embodiment, the projection device (100) can calculate a first reference position by applying the first pixel coordinate of the corrected image (720) to mathematical expression 2. The projection device (100) can calculate a second reference position and a third reference position by applying the second pixel coordinate and the third pixel coordinate of the corrected image (720) to mathematical expression 2, respectively.

[0151] Referring to FIG. 7A, a projection device (100) according to one embodiment can calculate the length of a line segment connecting reference positions as an interval between the reference positions. For example, the projection device (100) can calculate the length of a first line segment connecting a first reference position and a second reference position as a first reference interval. For example, the projection device (100) can calculate the length of a second line segment connecting a first reference position and a third reference position as a second reference interval.

[0152] Referring to FIG. 7B, the projection device (100) according to one embodiment can calculate an orthogonal distance between a first reference position and a second reference position as an interval between reference positions. For example, the projection device (100) can calculate a horizontal distance between second reference positions that are adjacent in a horizontal direction based on the first reference position as the first reference interval. For example, the projection device (100) can calculate a vertical distance between third reference positions that are adjacent in a vertical direction based on the first reference position as the second reference interval.

[0153] A projection device (100) according to one embodiment can consider a distance from at least one reference position based on a first reference position.

[0154] For example, the projection device (100) can calculate a reference interval by considering the interval between the first reference position and an adjacent second reference position or a third reference position.

[0155] Alternatively, for example, the projection device (100) may calculate a reference interval by considering the interval between two adjacent reference positions based on the first reference position. For example, the projection device (100) may calculate the reference interval of the first reference position by using the average of the first reference interval and the second reference interval.

[0156] Alternatively, referring to FIG. 7c, for example, the projection device (100) may calculate a reference interval by considering the intervals between the first reference position and eight adjacent reference positions. For example, the projection device (100) may also calculate the reference interval of the first reference position by using the average of the intervals between the first reference position and eight adjacent reference positions.

[0157] The method of calculating the reference interval is not limited to the examples described above.

[0158] FIG. 8 is an example of low-pass filters applied to each region of an input image according to one embodiment of the present disclosure.

[0159] Referring to Fig. 8, different low-pass filters may be applied to each region of an input image. For example, the input image is exemplified as having different low-pass filters applied to each of the first region (810), the second region (820), and the third region (830). Fig. 8 illustrates a reference image (515) configured as a reference location for referencing whether the input image is enlarged or reduced.

[0160] However, the number of low-pass filters is not limited to three, and may be at least two or more than three. In addition, although the input image region is illustrated as being divided into three, it is not limited thereto, and may be divided into at least two regions, a central region and an outer region, or may be divided into more than three regions. In Fig. 8, the first region (810) may correspond to the outer region, and the third region (830) may correspond to the central region.

[0161] The spacing between reference positions belonging to the first region (810) may be greater than or equal to a first threshold value. The projection device (100) may apply a first low-pass filter (801) when the spacing between reference positions is greater than or equal to the first threshold value. The first low-pass filter (801) is a strong low-pass filter and may have a low transmission frequency.

[0162] The interval between reference positions belonging to the second region (820) may be less than a first threshold value and greater than a second threshold value. The first threshold value is a value greater than the second threshold value. The projection device (100) may apply a second low-pass filter (802) as the interval between reference positions is less than the first threshold value and greater than the second threshold value. The second low-pass filter (802) is a low-pass filter that is weaker than the first low-pass filter (801) and may have a higher transmission frequency than the first low-pass filter (801).

[0163] The spacing between reference positions belonging to the third region (830) may be less than the second threshold. The projection device (100) may apply the third low-pass filter (803) as the spacing between reference positions is less than the second threshold. The third low-pass filter (803) is a low-pass filter that is weaker than the second low-pass filter (802) and may have a higher transmission frequency than the second low-pass filter (802).

[0164] The projection device (100) can prevent aliasing while maintaining image details as much as possible by applying different low-pass filters to each area. The projection device (100) can generate a corrected image with minimized aliasing.

[0165] In the present disclosure, applying a low-pass filter to an input image may mean convolving the low-pass filter with the input image. Convolution is an image processing technique that utilizes a filter with weights, and refers to a technique that obtains the sum of the multiplication of pixel values ​​of an input image and the corresponding weights (or coefficients) included in the filter. Here, the filter is also called a mask, window, or kernel. In other words, the numerical values ​​included in the Laplacian filter can be weights (numerical values ​​indicating how much of the corresponding pixels to utilize).

[0166] For example, the first low-pass filter (801) may be a filter that gives a weight of 0.5 to the pixel values ​​of the current input image and the surrounding pixel values.

[0167] For example, the second low-pass filter (802) may be a filter that gives a weight of 0.2 to the current pixel value of the current input image and a weight of 0.1 to the surrounding pixel values.

[0168] For example, the third low-pass filter (803) may be a filter that gives a weight of 0.9 to the current pixel value of the current input image and a weight of 0.1 to the surrounding pixel values.

[0169] The above-described weights are merely examples for convenience of explanation and are not limited thereto.

[0170] FIG. 9 is a flowchart illustrating an operation of a projection device according to one embodiment of the present disclosure to adjust the size of an effective pixel area of ​​a corrected image.

[0171] Referring to FIG. 9, in operation 910, the projection device (100) according to one embodiment can generate a correction image from an input image. The projection device (100) can generate a correction image in which pixel values ​​are entered through operations 410 and 420 of FIG. 4A.

[0172] In operation 920, the projection device (100) according to one embodiment can obtain positional relationship information between the screen and the projector. The positional relationship information can include the distance between the screen and the projector.

[0173] In operation 930, the projection device (100) according to one embodiment can adjust the size of the first area (effective pixel area) of the corrected image based on the positional relationship information.

[0174] According to one embodiment, a projection device (100) can adjust a distance parameter that determines an interval between reference positions based on positional relationship information. By adjusting the distance parameter, the projection device (100) can determine the size of an effective pixel area of ​​a corrected image.

[0175] For example, as the distance parameter increases, the spacing between reference locations increases, and the effective pixel area of ​​the corrected image corresponding to the reference locations may decrease. For example, as the distance parameter decreases, the spacing between reference locations decreases, and the effective pixel area of ​​the corrected image corresponding to the reference locations may increase.

[0176] For example, the projection device (100) can increase the distance parameter value so that the size of the effective pixel area of ​​the corrected image becomes smaller as the distance between the projection device (100) and the screen increases.

[0177] Additionally, for example, the projection device (100) can lower the distance parameter value so that the size of the effective pixel area of ​​the corrected image increases as the distance between the projection device (100) and the screen becomes closer.

[0178] In operation 940, a projection device (100) according to one embodiment can control a projector to project a corrected image onto a screen. The projection device (100) can display the projected image on the screen.

[0179] According to one embodiment, a projection device (100) can display the size of an effective pixel area within a projected image at a constant level even when the distance between the projection device (100) and the screen (50) increases or decreases by adjusting a distance parameter based on positional relationship information.

[0180] FIG. 10 is a diagram illustrating an operation of a projection device according to one embodiment of the present disclosure to adjust the size of an effective pixel area of ​​a corrected image according to a distance parameter.

[0181] Referring to FIG. 10, a projection device (100) according to one embodiment can adjust the size of an effective pixel area of ​​a correction image according to a distance parameter.

[0182] The distance parameter may be a factor that determines the interval between reference positions of the input image. The projection device (100) can adjust the distance parameter to widen or narrow the interval between reference positions of the input image. The projection device (100) can adjust the distance parameter to enlarge or reduce the effective pixel area of ​​the corrected image. Here, even if the distance parameter is adjusted, the overall size of the corrected image remains constant, and the effective pixel area can be enlarged or reduced.

[0183] For example, in Equation 2, when the u and v values ​​of the corrected image increase by 1, the x and y values ​​of the reference positions can increase in proportion to d. For example, when (u, v) increases in the order of (0, 1), (0, 2), (0, 3), if d is 1, the reference positions sequentially increase in the order of (0, 1), (0, 2), (0, 3), and if d is 2, the reference positions can increase in wider intervals, such as (0, 2), (0, 4), (0, 6).

[0184] For example, referring to 1001, if the distance parameter is small, the reference interval becomes narrower, and the effective pixel area (1021) of the correction image (1020) may be enlarged. For example, the reference positions included in the first reference image (1070) may exist within the coordinate range of the input image (1010). Accordingly, the projection device (100) may generate a correction image (1020) having a large effective pixel area (1021) by referring to the pixel values ​​of the input image (1010) having a narrow reference interval. Here, the reference image means an image composed of reference positions.

[0185] Or, for example, referring to 1002, if the distance parameter is large, the reference interval may become wide, and the effective pixel area (1051) of the correction image (1050) may be reduced. For example, at least some of the reference positions included in the second reference image (1080) may exist outside the coordinate range of the input image (1010). Accordingly, the projection device (100) may generate a correction image (1050) having a small effective pixel area (1051) by referring to the pixel values ​​of the input image (1010) having a wide reference interval.

[0186] The projection device (100) according to one embodiment can set the distance parameter to an appropriate value so that the reference position is located within the coordinate range of the input image (1010). For example, the projection device (100) can adjust the distance parameter so that the effective pixel area (1021) is smaller than that of the corrected image (1020) of 1001 and the effective pixel area (1051) is larger than that of the corrected image (1050) of 1002.

[0187] For example, the distance parameter may be a value appropriately determined by the image resolution and lens parameters. For example, the distance parameter may also be adjusted through positional relationship information between the screen and the projector, as described in FIG. 11. For example, the distance parameter may also be adjusted by user settings.

[0188] Referring to 1001, when a projection device (100) projects a correction image (1020) having a large effective pixel area (1021) and a small black area (1022) through a fish-eye lens, a projection screen (1030) can be displayed on a screen. There is no distortion or deformation in the effective pixel area of ​​the projection screen (1030), and the size of the effective pixel area can be large, like the correction image (1020).

[0189] Referring to 1002, when a projection device (100) projects a correction image (1050) having a large effective pixel area (1051) and a small black area (1052) through a fish-eye lens, a projection screen (1060) can be displayed on a screen. There is no distortion or deformation in the effective pixel area of ​​the projection screen (1060), and the size of the effective pixel area can be small, like the correction image (1050).

[0190] FIG. 11 is a diagram showing an operation of determining the size of a projection screen and the size of a correction image according to positional relationship information between a projection device and a screen according to one embodiment of the present disclosure.

[0191] Referring to FIG. 11, a projection device (100) according to one embodiment may include at least one sensor. The projection device (100) may obtain positional relationship information between the projection device (100) and the screen (50) through the at least one sensor. For example, the positional relationship information may include a distance between the projection device (100) and the screen (50). For example, the at least one sensor may include a distance sensor.

[0192] The projection device (100) can display a smaller projection screen (1110) on the screen (50) as the distance between the projection device (100) and the screen (50) becomes closer (see 1101). The projection device (100) can display a larger projection screen (1120) on the screen (50) as the distance between the projection device (100) and the screen (50) becomes longer (see 1102 and 1103).

[0193] In one embodiment, as the distance between the projection device (100) and the screen (50) becomes shorter, the projection screen (1110) becomes smaller, and thus the effective pixel area (1111) may also become smaller. As the distance between the projection device (100) and the screen (50) becomes longer, the projection screen (1120) becomes larger, and thus the effective pixel area (1130) may also become larger.

[0194] In one embodiment, the projection device (100) can display a constant size of an effective pixel area within a projection screen even when the distance between the projection device (100) and the screen (50) increases or decreases by adjusting a distance parameter. For example, a mural or a framed image can always be displayed on the screen (50) at a constant size regardless of whether the distance between the projection device (100) and the screen (50) increases or decreases.

[0195] For example, the projection device (100) can adjust a distance parameter that determines the interval between reference positions based on positional relationship information. By adjusting the distance parameter, the projection device (100) can determine the size of the effective pixel area of ​​the corrected image.

[0196] For example, in 1103, the projection device (100) can set the distance parameter to be large so that the size of the effective pixel area of ​​the corrected image becomes smaller as the distance between the projection device (100) and the screen (50) increases. By setting the distance parameter to be large, the projection device (100) can maintain the size of the effective pixel area (1140) constant even if the projection screen (1120) becomes larger.

[0197] In addition, for example, although not shown, the projection device (100) may set the distance parameter to be small so that the size of the effective pixel area of ​​the corrected image increases as the distance between the projection device (100) and the screen (50) becomes closer. By setting the distance parameter to be small, the projection device (100) can maintain the size of the effective pixel area constant even if the projection screen becomes smaller.

[0198] FIG. 12 is a diagram illustrating an operation of a projection device according to one embodiment of the present disclosure to project an image onto a multi-faceted screen. FIG. 13 is an example of a multi-faceted input image and a multi-faceted corrected image according to one embodiment of the present disclosure.

[0199] Referring to FIG. 12, a projection device (100) according to one embodiment can perform projection in a 360-degree direction. The projection device (100) can project an image onto a screen (1250) configured with multiple sides. The screen (1250) can configure multiple wall surfaces. For example, the screen (1250) can include at least one of a front side, a side (right side, left side), a ceiling, and a floor.

[0200] A projection device (100) according to one embodiment can generate a corrected image (1220) from an input image (1210). The projection device (100) can generate a corrected image (1220) having barrel distortion corresponding to the inverse deformation of pincushion distortion. The projection device (100) can project the corrected image (1220) onto a screen (1250). Pincushion distortion may not occur on a projection screen (1230) projected through the projection device (100). As the corrected image (1220) is distorted through a fisheye lens, it can be projected onto a multi-faceted screen (1250) in the same form as the input image (1210).

[0201] According to one embodiment, the projection device (100) can obtain positional relationship information between the projection device (100) and the screen. For example, the projection device (100) can obtain distance information, angle information, etc. between the projection device (100) and the walls of the screen. For example, the projection device (100) can obtain distance information between the projection device (100) and the walls, such as the front, side, ceiling, and floor, through a distance sensor. For example, the projection device (100) can obtain distance information between the walls, such as the front, side, ceiling, and floor, through a user input.

[0202] A projection device (100) according to one embodiment can calculate projection points where pixels passing through a fish-eye lens (140) meet each wall surface. For example, the projection device (100) can calculate the positions of projection points to be projected onto each wall surface when an input image passes through a fish-eye lens (140) based on distance information between the walls and pixel coordinates of the image.

[0203] A projection device (100) according to one embodiment can calculate a reference position by projecting a projection point into two dimensions. FIG. 13 illustrates a reference image (1310) indicating reference positions of pixels of an input image. The reference image (1310) may include reference positions of pixels that are distorted when each of a plurality of pixels belonging to a correction image (1320) is projected through a fish-eye lens. The spacing between the plurality of pixels belonging to the correction image (1320) may be constant.

[0204] According to one embodiment, a projection device (100) can obtain pixel values ​​of an input image to be referenced for pixel values ​​of a correction image (1320) using a reference position. For example, the projection device (100) can use pixel values ​​of an input image corresponding to the reference position as pixel values ​​of a correction image. In this regard, the operations described in FIGS. 4A and 4B can be applied.

[0205] According to one embodiment, a projection device (100) can determine a low-pass filter to be applied to an input image using a reference position. The projection device (100) can calculate pixel values ​​of a corrected image using the determined low-pass filter. For example, the projection device (100) can use different low-pass filters depending on the area between walls, the center area, the outer area, etc. In this regard, the operation described in FIG. 6 can be applied.

[0206] FIG. 14 is a diagram illustrating a graphical user interface for adjusting a correction image according to one embodiment of the present disclosure.

[0207] Referring to FIG. 14, a projection device (100) according to one embodiment may output a graphical user interface for inquiring whether to adjust a correction image on a screen (50). The graphical user interface may include a correction image (1410) generated before being projected on the screen (50) and an inquiry (1420) regarding whether to adjust the correction image (1410). The correction image (1410) may be displayed as a grid image, but is not limited thereto. The inquiry (1420) may include a user inquiry such as, "Do you want to adjust the correction image?"

[0208] The user can check whether the inverse distortion of the corrected image generated from the input image is appropriate before being projected onto the screen (50) through the graphical user interface, and whether the ratio of the effective pixel area to the black area is appropriate.

[0209] A user can adjust the degree of correction of a corrected image (1410) through a control device (e.g., a remote control) connected to the projection device (100) via wired or wireless means. For example, the projection device (100) can change the degree of correction of a corrected image (1410) based on a user input. For example, the projection device (100) can change the size of a central area, a peripheral area, a valid pixel area, a black area, etc. of the corrected image (1410).

[0210] The projection device (100) can project a customized image on a screen by generating a customized correction image according to user input.

[0211] FIG. 15 is a detailed configuration diagram of a projection device according to one embodiment of the present disclosure.

[0212] Referring to FIG. 15, the projection device (100) may include a tuner unit (1540), a processor (110), a communication unit (1550), a detection unit (1530), an input / output unit (1570), a video processing unit (1580), an audio processing unit (1585), an audio output unit (1560), a power supply unit (1595), a memory (120), a projector (130), a fish-eye lens (140), and a sensor (150). In FIG. 15, any content overlapping with the above-described content is omitted.

[0213] A tuner unit (1540) according to one embodiment can select and tune only the frequency of a channel to be received by the projection device (100) among many radio wave components through amplification, mixing, resonance, etc. of a broadcast signal received wired or wirelessly. The broadcast signal includes audio, video, and additional information (e.g., EPG (Electronic Program Guide)).

[0214] The tuner unit (1540) can receive broadcast signals from various sources, such as terrestrial broadcasting, cable broadcasting, satellite broadcasting, and Internet broadcasting. The tuner unit (1540) can also receive broadcast signals from sources, such as analog broadcasting or digital broadcasting.

[0215] The communication unit (1550) can transmit and receive data or signals with an external device or server. For example, the communication unit (1550) may include a Wi-Fi module, a Bluetooth module, an infrared communication module, a wireless communication module, a LAN module, an Ethernet module, a wired communication module, etc. In this case, each communication module may be implemented in the form of at least one hardware chip.

[0216] The Wi-Fi module and Bluetooth module perform communication in the Wi-Fi and Bluetooth modes, respectively. When using the Wi-Fi module or Bluetooth module, various connection information such as the SSID and session key are first transmitted and received, and after establishing a communication connection using this, various information can be transmitted and received. The wireless communication module may include at least one communication chip that performs communication according to various wireless communication standards such as Zigbee, 3G (3rd Generation), 3GPP (3rd Generation Partnership Project), LTE (Long Term Evolution), LTE-A (LTE Advanced), 4G (4th Generation), and 5G (5th Generation).

[0217] According to one embodiment, a detection unit (1530) detects a user's voice, a user's image, or a user's interaction, and may include a microphone (1531), a camera unit (1532), and a light receiving unit (1533).

[0218] The microphone (1531) receives the user's spoken voice. The microphone (1531) can convert the received voice into an electrical signal and output it to the processor (110).

[0219] The optical receiver (1533) receives an optical signal (including a control signal) from an external control device through a projector (130), etc. The optical receiver (1533) can receive an optical signal corresponding to a user input (e.g., touch, press, touch gesture, voice, or motion) from the control device. A control signal can be extracted from the received optical signal under the control of the processor (110).

[0220] The input / output unit (1570) according to one embodiment can receive video (e.g., moving images, etc.), audio (e.g., voice, music, etc.), and additional information (e.g., EPG, etc.) from the outside of the projection device (100). The input / output unit (1570) can include any one of a High-Definition Multimedia Interface (HDMI), a Mobile High-Definition Link (MHL), a Universal Serial Bus (USB), a Display Port (DP), a Thunderbolt, a Video Graphics Array (VGA) port, an RGB port, a D-subminiature (D-SUB), a Digital Visual Interface (DVI), a component jack, and a PC port.

[0221] A video processing unit (1580) according to one embodiment performs processing on video data received by the projection device (100). The video processing unit (1580) can perform various image processing operations, such as decoding, scaling, noise filtering, frame rate conversion, and resolution conversion on the video data.

[0222] According to one embodiment, the processor (110) may acquire an input image by executing one or more instructions stored in the memory (120). The input image may be an image previously stored in the memory (120) or an image received from an external device through the tuner unit (1540) or the communication unit (1550). In addition, the input image may be an image on which various image processing such as decoding, scaling, noise filtering, frame rate conversion, and resolution conversion are performed in the video processing unit (1580).

[0223] According to one embodiment, a projector (130) converts an image signal, a data signal, an OSD signal, a control signal, etc. processed by a processor (110) to generate a driving signal.

[0224] The audio processing unit (1585) processes audio data. The audio processing unit (1585) may perform various processing operations, such as decoding, amplification, and noise filtering, on audio data. Meanwhile, the audio processing unit (1585) may include multiple audio processing modules to process audio corresponding to multiple contents.

[0225] The audio output unit (1560) outputs audio included in a broadcast signal received through the tuner unit (1540) under the control of the processor (110). The audio output unit (1560) can output audio (e.g., voice, sound) input through the communication unit (1550) or the input / output unit (1570). In addition, the audio output unit (1560) can output audio stored in the memory (120) under the control of the processor (110). The audio output unit (1560) can include at least one of a speaker, a headphone output terminal, or a S / PDIF (Sony / Philips Digital Interface:) output terminal.

[0226] The power supply unit (1595) supplies power input from an external power source to components inside the projection device (100) under the control of the processor (110). In addition, the power supply unit (1595) can supply power output from one or more batteries (not shown) located inside the projection device (100) to the internal components under the control of the processor (110).

[0227] A sensor (150) according to one embodiment can detect a state around the projection device (100) and transmit the detected information to the processor (110). The sensor (150) can include an image sensor and a depth sensor (or distance sensor).

[0228] An image sensor according to one embodiment can acquire image frames, such as still images or video images. For example, the image sensor can capture images outside the projection device (100). For example, the image sensor can capture images projected onto a screen. In this case, the images captured by the image sensor can be processed by the processor (110) or a separate image processor.

[0229] A depth sensor according to one embodiment can obtain depth information about one or more objects included in a space. The depth information can correspond to a distance from the depth sensor to a specific object, and the greater the distance from the depth sensor to the specific object, the greater the depth value. A depth sensor according to one embodiment can obtain depth information about an object in various ways, and for example, can obtain depth information using at least one of a time-of-flight (TOF) method, a stereo image method, and a structured light method.

[0230] A depth sensor according to one embodiment may include at least one camera and may acquire depth information about an actual space included in a field of view (FOV) of the camera included in the depth sensor. The depth sensor may sense a distance to a center or at least one reference point included in a projection device and a screen.

[0231] In addition, the sensor (150) may include, in addition to the image sensor and the depth sensor, an acceleration sensor, a position sensor, a temperature / humidity sensor, an illuminance sensor, a geomagnetic sensor, a gyroscope sensor, and a microphone, but is not limited thereto.

[0232] According to one embodiment of the present disclosure, the one or more instructions are individually or in combination executed by the at least one processor, so that the projection device calculates a plurality of reference positions based on pixel coordinates of each of a plurality of pixels of the corrected image, and sets a pixel value of each of a plurality of pixels of the corrected image by referring to a pixel value of the input image corresponding to each of the calculated plurality of reference positions, thereby generating a corrected image that corrects distortion of the input image projected onto a screen through the fish-eye lens.

[0233] By executing the one or more instructions individually or in combination by the at least one processor according to one embodiment of the present disclosure, the projection device controls the projector to project the generated corrected image onto the screen through the fish-eye lens.

[0234] A projection device according to one embodiment of the present disclosure can calculate the plurality of reference positions based on at least one of the pixel coordinates of each of the plurality of pixels of the corrected image, a distance parameter, a specification of the fish-eye lens, and a distance between the center coordinates of the corrected image and the pixel coordinates of the corrected image.

[0235] The spacing between the plurality of reference locations according to one embodiment of the present disclosure may correspond to the spacing between projection points as the plurality of pixels of the generated corrected image pass through the fish-eye lens.

[0236] A projection device according to one embodiment of the present disclosure can calculate the plurality of reference positions corresponding to each of the plurality of pixels of the corrected image.

[0237] A projection device according to one embodiment of the present disclosure can set a pixel value of the corrected image by referring to a pixel value of the input image corresponding to any one of the plurality of reference positions, when any one of the plurality of reference positions is within a pixel coordinate range of the input image.

[0238] A projection device according to one embodiment of the present disclosure can generate an effective pixel area of ​​the corrected image by referring to a pixel value of each of a plurality of pixels of the input image corresponding to each of the plurality of reference locations.

[0239] The effective pixel area of ​​the corrected image according to one embodiment of the present disclosure may represent an inverse transformation of the distortion of the image generated by the fish-eye lens.

[0240] A projection device according to one embodiment of the present disclosure can calculate a plurality of reference positions corresponding to each of a plurality of pixels of the corrected image.

[0241] A projection device according to one embodiment of the present disclosure can set a pixel value of the corrected image corresponding to any one of the plurality of reference positions to a predetermined value when any one of the plurality of reference positions is outside the pixel coordinate range of the input image.

[0242] A projection device according to one embodiment of the present disclosure can generate a black area of ​​the corrected image by setting a pixel value of the corrected image corresponding to each of the plurality of reference locations to a predetermined value.

[0243] A projection device according to one embodiment of the present disclosure can determine the size of an effective pixel area of ​​the corrected image based on a distance parameter that determines an interval between the plurality of reference locations.

[0244] In one embodiment of the present disclosure, as the distance parameter increases, the effective pixel area of ​​the corrected image may decrease, and as the distance parameter decreases, the effective pixel area of ​​the corrected image may increase.

[0245] A projection device according to one embodiment of the present disclosure can obtain positional relationship information between the projection device and the screen through at least one sensor.

[0246] A projection device according to one embodiment of the present disclosure can adjust a distance parameter that determines an interval between the plurality of reference positions based on the positional relationship information.

[0247] A projection device according to one embodiment of the present disclosure can determine the size of an effective pixel area of ​​the corrected image by adjusting the distance parameter.

[0248] A projection device according to one embodiment of the present disclosure can adjust the distance parameter so that the size of the effective pixel area of ​​the corrected image becomes smaller as the distance between the projection device and the screen increases.

[0249] A projection device according to one embodiment of the present disclosure can calculate an interval between a first reference position corresponding to the first pixel and a second reference position corresponding to the second pixel.

[0250] A projection device according to one embodiment of the present disclosure can determine a low-pass filter based on a distance between the first reference position and the second reference position.

[0251] A projection device according to one embodiment of the present disclosure can calculate a pixel value of the first pixel of the corrected image by applying the low-pass filter to the input image.

[0252] A projection device according to one embodiment of the present disclosure may apply a first low-pass filter to the input image when a distance between the first reference position and the second reference position is greater than or equal to a threshold value.

[0253] A projection device according to one embodiment of the present disclosure may apply a second low-pass filter when a distance between the first reference position and the second reference position is less than a threshold value.

[0254] In one embodiment of the present disclosure, the transmission frequency of the first low-frequency filter may be lower than the transmission frequency of the second low-frequency filter.

[0255] In one embodiment of the present disclosure, the distance between the first reference position and the second reference position may include at least one of a length of a first direction line segment connecting the first reference position and the second reference position, and an orthogonal distance between the first reference position and the second reference position.

[0256] A method of operating a projection device according to one embodiment of the present disclosure includes the steps of: calculating a plurality of reference positions based on pixel coordinates of each of a plurality of pixels of a correction image, and setting a pixel value of each of a plurality of pixels of the correction image by referring to a pixel value of an input image corresponding to each of the calculated plurality of reference positions, thereby generating a correction image that corrects distortion of the input image projected onto a screen through a fish-eye lens; and controlling a projector to project the generated correction image onto the screen through the fish-eye lens.

[0257] The step of generating the above-described corrected image may include a step of calculating the reference position based on at least one of pixel coordinates of the corrected image, a distance parameter, a specification of the fish-eye lens, and a distance between the center coordinates of the corrected image and the pixel coordinates of the corrected image.

[0258] The step of generating the above-described corrected image may include a step of calculating a reference position corresponding to each of the plurality of pixels of the above-described corrected image.

[0259] The step of generating the above-described corrected image may include a step of referencing a pixel value of the input image as a pixel value of the above-described corrected image, depending on whether the reference location is within a pixel coordinate range of the above-described input image.

[0260] The step of generating the above-described corrected image may include a step of generating a valid pixel area of ​​the above-described corrected image by referring to pixel values ​​of the above-described input image.

[0261] The step of generating the above-described corrected image may include a step of calculating a reference position corresponding to each of the plurality of pixels of the above-described corrected image.

[0262] The step of generating the above-described corrected image may include a step of setting a pixel value of the above-described corrected image to black when the above-described reference location is outside the pixel coordinate range of the above-described input image.

[0263] The step of generating the above-described corrected image may include a step of generating a black area of ​​the above-described corrected image by setting pixel values ​​of the above-described corrected image to black.

[0264] The step of generating the above-described corrected image may include a step of determining a size of an effective pixel area of ​​the above-described corrected image based on a distance parameter that determines a distance between the above-described reference locations.

[0265] The step of generating the above-described correction image may include a step of calculating a distance between a first reference position corresponding to the first pixel and a second reference position corresponding to the second pixel.

[0266] The step of generating the above-described correction image may include a step of determining a low-pass filter based on a distance between the first reference position and the second reference position.

[0267] The step of generating the above-described corrected image may include a step of calculating the first pixel value of the above-described corrected image by applying the low-pass filter to the above-described input image.

[0268] In one embodiment of the present disclosure, a computer-readable recording medium having recorded thereon a program for performing a method of operating a projection device that projects an image on a computer may be provided.

[0269] A device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, the term "non-transitory storage medium" simply means a tangible device that does not contain signals (e.g., electromagnetic waves). This term does not distinguish between cases where data is permanently stored in the storage medium and cases where data is temporarily stored. For example, a "non-transitory storage medium" may include a buffer in which data is temporarily stored.

[0270] According to one embodiment, the method according to various embodiments disclosed in the present document may be provided as included in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or may be distributed online (e.g., downloaded or uploaded) through an application store or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., a downloadable app) may be temporarily stored or temporarily generated in a machine-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

Claims

1. In a projection device (100) that projects an image, Projector (130); Fish-eye lens (140); A memory (120) storing one or more instructions; and At least one processor (110) coupled to the above memory (120) and including a processing circuit, The projection device (100) executes the one or more instructions individually or collectively by the at least one processor (110), By calculating a plurality of reference positions based on the pixel coordinates of each of a plurality of pixels of the correction image (220), and setting the pixel value of each of the plurality of pixels of the correction image (220) by referring to the pixel value of the input image (210) corresponding to each of the calculated plurality of reference positions, a correction image (220) is generated that corrects the distortion of the input image (210) projected onto the screen through the fish-eye lens (140), A projection device (100) configured to control the projector (130) to project the generated correction image (220) onto the screen through the fish-eye lens (140).

2. In paragraph 1, The projection device (100) executes the one or more instructions individually or in combination by the at least one processor (110). A projection device (100) configured to calculate the plurality of reference positions based on at least one of the pixel coordinates of each of the plurality of pixels of the correction image (220), a distance parameter, a specification of the fish-eye lens (140), and a distance between the center coordinates of the correction image (220) and the pixel coordinates of the correction image (220).

3. In paragraph 1 or 2, A projection device (100), wherein the spacing between the plurality of reference positions corresponds to the spacing between projection points as the plurality of pixels of the generated correction image (220) pass through the fish-eye lens (140).

4. In any one of paragraphs 1 to 3, The projection device (100) executes the one or more instructions individually or in combination by the at least one processor (110). Calculating the plurality of reference locations corresponding to each of the plurality of pixels of the above correction image (220), When one of the plurality of reference locations is within the pixel coordinate range (520) of the input image (210), the pixel value of the correction image (220) is set by referring to the pixel value of the input image (210) corresponding to one of the plurality of reference locations, A projection device (100) configured to generate an effective pixel area (221) of the corrected image (220) by referring to the pixel value of each of the plurality of pixels of the input image (210) corresponding to each of the plurality of reference locations.

5. In paragraph 4, The effective pixel area (221) of the above correction image (220) is a projection device (100) that represents the reverse transformation of the distortion of the image generated by the fish-eye lens (140).

6. In any one of paragraphs 1 to 5, The projection device (100) executes the one or more instructions individually or in combination by the at least one processor (110). Calculating the plurality of reference locations corresponding to each of the plurality of pixels of the above correction image (220), When one of the above multiple reference locations is out of the pixel coordinate range (520) of the input image (210), the pixel value of the correction image (220) corresponding to one of the above multiple reference locations is set to a predetermined value, A projection device (100) configured to generate a black area (222) of the correction image (220) by setting pixel values ​​of the correction image (220) corresponding to each of the plurality of reference locations to a predetermined value.

7. In any one of paragraphs 1 to 6, The projection device (100) executes the one or more instructions individually or in combination by the at least one processor (110). A projection device (100) configured to determine the size of an effective pixel area (221) of the correction image (220) based on a distance parameter that determines an interval between the plurality of reference locations.

8. In paragraph 7, As the above distance parameter increases, the effective pixel area (221) of the corrected image (220) becomes smaller, A projection device (100), wherein as the above distance parameter decreases, the effective pixel area (221) of the above correction image (220) increases.

9. In any one of paragraphs 1 to 8, further comprising at least one sensor (150), The projection device (100) executes the one or more instructions individually or in combination by the at least one processor (110). Obtaining positional relationship information between the projection device (100) and the screen through at least one sensor (150), Based on the above location relationship information, a distance parameter for determining the interval between the plurality of reference locations is adjusted, A projection device (100) configured to determine the size of an effective pixel area (221) of the corrected image (220) by adjusting the above distance parameter.

10. In paragraph 9, The projection device (100) executes the one or more instructions individually or in combination by the at least one processor (110). A projection device (100) configured to adjust the distance parameter so that the size of the effective pixel area (221) of the correction image (220) becomes smaller as the distance between the projection device (100) and the screen increases.

11. In any one of paragraphs 1 to 10, The above correction image (220) includes a first pixel and a second pixel adjacent to the first pixel, The projection device (100) executes the one or more instructions individually or in combination by the at least one processor (110). Calculate the interval between the first reference position corresponding to the first pixel and the second reference position corresponding to the second pixel, Based on the interval between the first reference position and the second reference position, a low-pass filter is determined, A projection device (100) configured to calculate a pixel value of the first pixel of the corrected image (220) by applying the low-pass filter to the input image (210).

12. In paragraph 11, The projection device (100) executes the one or more instructions individually or in combination by the at least one processor (110). Since the gap between the first reference position and the second reference position is greater than or equal to a threshold value, a first low-pass filter is applied to the input image (210), Since the gap between the first reference position and the second reference position is less than the threshold value, a second low-pass filter is applied, A projection device (100) wherein the transmission frequency of the first low-frequency filter is lower than the transmission frequency of the second low-frequency filter.

13. In clause 11 or 12, A projection device (100), wherein the distance between the first reference position and the second reference position includes at least one of a length of a first direction line segment connecting the first reference position and the second reference position, and an orthogonal distance between the first reference position and the second reference position.

14. In the operating method of a projection device (100) that projects an image, A step (405: 410, 420) of generating a correction image (220) that corrects distortion of the input image (210) projected onto a screen through a fish-eye lens (140) by calculating a plurality of reference positions based on pixel coordinates of each of a plurality of pixels of the correction image (220) and setting a pixel value of each of a plurality of pixels of the correction image (220) by referring to the pixel value of the input image (210) corresponding to each of the calculated plurality of reference positions; and A method comprising a step (430) of controlling a projector (130) to project the generated correction image (220) onto the screen through a fish-eye lens (140).

15. A step (405: 410, 420) of generating a correction image (220) that corrects distortion of the input image (210) projected onto a screen through a fish-eye lens (140) by calculating a plurality of reference positions based on pixel coordinates of each of a plurality of pixels of the correction image (220) and setting a pixel value of each of a plurality of pixels of the correction image (220) by referring to the pixel value of the input image (210) corresponding to each of the calculated plurality of reference positions; and A computer-readable recording medium having recorded thereon a program for executing a method of operating a projection device (100) on a computer, the method including the step (430) of controlling a projector (130) to project the generated correction image (220) onto the screen through a fish-eye lens (140).

Images