Image projection method and projector

Abstract

To provide an image projection method that can execute appropriate geometric correction for a projection surface having a complex shape.SOLUTION: An image projection method includes: projecting a plurality of adjustment points relatively defined in an image on a screen; determining the positions of the plurality of adjustment points on the screen; determining whether each of a plurality of sides connecting the adjustment points adjacent to each other is a straight line or a curved line; executing geometric correction for an image within a range corresponding to an area defined by the plurality of sides including the straight lines and curved lines so as to realize the plurality of sides defining the area; and projecting an image for which the geometric correction is executed on the screen.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an image projection method and a projector.

Background Art

[0002] Patent Document 1 discloses a technique for performing geometric correction processing of a projection image so as to be projected onto a screen in an arbitrary shape by performing cubic spline interpolation using the moving positions of lattice points projected onto a curved screen.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique described in Patent Document 1, since the attributes of each line connecting lattice points cannot be specified individually, it may be difficult to perform complex geometric correction.

Means for Solving the Problems

[0005] One aspect is an image projection method including: projecting a plurality of adjustment points defined relative to an image onto a screen; determining positions of the plurality of adjustment points on the screen; determining whether each of a plurality of sides connecting the adjacent adjustment points is a straight line or a curve; performing geometric correction on the image in a range corresponding to an area defined by the plurality of sides including the straight line and the curve so as to realize the plurality of sides defining the area; and projecting the image subjected to the geometric correction onto the screen.

[0006] Another aspect is a projector including: a projection device configured to project a plurality of adjustment points defined relative to an image and the image onto a screen; an input interface configured to determine positions of the plurality of adjustment points on the screen; a processing circuit configured to determine whether each of a plurality of sides connecting the adjacent adjustment points is a straight line or a curve; and a correction circuit configured to perform geometric correction on the image within a range corresponding to an area defined by the plurality of sides including the straight lines and the curves so as to realize the plurality of sides defining the area. BRIEF DESCRIPTION OF THE DRAWINGS

[0007]

Figure 1

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[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments illustrate a system for embodying the technical idea of the present invention, an apparatus and a method used in this system. The technical idea of the present invention is not limited to the types and configurations of each apparatus, network topology, a series of processes, etc. as described below. In the drawings, the same or similar elements may be respectively denoted by the same or similar reference numerals, and redundant descriptions may be omitted.

[0009] As shown in FIG. 1, a projection system 1 according to an embodiment includes, for example, a projector 10 that projects an image D onto a screen SC, and a control device 20 that communicates with the projector 10 via a network NW. The projection surface of the screen SC may have a flat surface or a curved surface. Alternatively, the projection surface may be a combination of a plurality of flat surfaces and a plurality of curved surfaces, and may be discontinuous.

[0010] The projector 10 includes an input interface (I / F) 11, a control circuit 12, and a projection device 13. The input I / F 11 includes, for example, a communication I / F 111 and an input device 112. The input I / F 11 detects various inputs by the user and outputs a signal corresponding to the user's input to the control circuit 12.

[0011] The communication I / F 111 is communicably connected to the control device 20 by establishing a communication link with the control device 20 via the network NW in accordance with the control by the control circuit 12. The communication I / F 111 includes a communication circuit that processes signals transmitted on the communication link. The communication link may be wired, wireless, or a combination of wired and wireless. That is, the communication I / F 111 may be directly connected to the control device 20 or indirectly connected via another relay device. The communication I / F 111 may include, for example, an antenna that transmits and receives wireless signals, a receptacle into which a plug of a communication cable is inserted, and the like.

[0012] The communication I / F 111 sequentially acquires, for example, the image data transmitted from the control device 20 and outputs it to the control circuit 12. The communication I / F 111 may acquire the image data reproduced in another playback device 30. For this reason, the projection system 1 may include the playback device 30. As the playback device 30, for example, a personal computer, a tablet terminal, a smartphone, a digital media player, a camera, a movie player, a wireless display adapter, a television tuner, a video game console, or any other device having a function of supplying image data to the projector 10 can be adopted.

[0013] The input device 112 detects the input by the user and outputs a signal corresponding to the user's input to the control circuit 12. As the input device 112, for example, various switches such as push buttons and touch sensors, pointing devices such as mice and touch panels, and various input devices such as keyboards can be adopted. In order to detect the user's voice as an input using voice recognition technology, a microphone may be adopted as the input device 112. Alternatively, as the input device 112, a gesture sensor that detects the user's gesture as an input may be adopted. The input device 112 may be a pointing device that detects the position of an indicator on the screen SC. The input device 112 may include a wired or wireless remote controller. The input I / F 11 may detect the user's input to the input unit 22 of the control device 20 via the communication I / F 111.

[0014] The projection device 13 includes a light source 131, a display panel 132, and an optical system 133. The light source 131 includes a light-emitting element such as a discharge lamp or a solid-state light source. The display panel 132 is a light modulation element having a plurality of pixels. The display panel 132 modulates the light emitted from the light source 131 according to the image signal output from the control circuit 12. The display panel 132 is, for example, a transmissive or reflective liquid crystal light valve. The display panel 132 may be a digital micromirror device that controls the reflection of light for each pixel. Needless to say, the display panel 132 in one projection device 13 may include a plurality of display panels that modulate light of different wavelengths. The optical system 133 projects the image D onto the screen SC by irradiating the light modulated by the display panel 132 onto the screen SC. The optical system 133 may include various lenses, mirrors, drive mechanisms, and the like.

[0015] The control circuit 12 includes an OSD processing circuit 121, a geometric correction circuit 122, a processing circuit 123, and a storage medium 124. The control circuit 12 controls the projection device 13 to project the image D based on the image data input from the communication I / F 111 onto the screen SC. The control circuit 12 performs geometric correction on the image D projected onto the screen SC based on the user input detected by the input unit 22 or the input device 112.

[0016] The OSD processing circuit 121 generates a plurality of adjustment points to be projected onto the screen SC by, for example, on-screen display (OSD) technology for geometric correction of the image D. The OSD processing circuit 121 projects the plurality of adjustment points via the projection device 13. Each position of the plurality of adjustment points on the screen SC is adjusted according to the user input to the input unit 22 or the input device 112. That is, the input I / F 11 detects an input for adjusting the positions of the plurality of adjustment points.

[0017] The geometric correction circuit 122 performs geometric correction of an image by controlling the display panel 132 based on the positions of a plurality of adjustment points. Specifically, the geometric correction circuit 122 performs geometric correction based on the conversion coefficients calculated by the processing circuit 123. As a series of processes for geometric correction by the geometric correction circuit 122 and the processing circuit 123, various two-dimensional coordinate conversions such as affine transformation and homography transformation, and various interpolation methods such as bilinear interpolation and bicubic interpolation can be appropriately executed.

[0018] The processing circuit 123 constitutes a processing device of a computer that processes operations necessary for the operation of the projector 10. The processing circuit 123 realizes various functions described in the embodiments, for example, by executing a control program stored in the storage medium 124. At least a part of the OSD processing circuit 121 and the geometric correction circuit 122 may be realized by the processing circuit 123. As the processing device constituting at least a part of the processing circuit 123, for example, various logical operation circuits such as a central processing unit (CPU), a digital signal processor (DSP), a programmable logic device (PLD), and an application-specific integrated circuit (ASIC) can be adopted. The processing circuit 123 may be composed of integrated hardware or may be composed of a plurality of separate hardwares.

[0019] The storage medium 124 is a computer-readable storage device that stores a control program indicating a series of processes necessary for the operation of the processing circuit 123 and various data. As the storage medium 124, for example, a semiconductor memory or various disk media can be adopted. The storage medium 124 is not limited to a non-volatile auxiliary storage device and may include a volatile main storage device such as a register or a cache memory. At least a part of the storage medium 124 may be constituted by a part of the processing circuit 123. The storage medium 124 may be composed of integrated hardware or may be composed of a plurality of separate hardwares.

[0020] The control device 20 includes, for example, a communication unit 21, an input unit 22, a display unit 23, and a control unit 24. The communication unit 21 includes a communication circuit that establishes a communication link with the projector 10 and processes signals transmitted on the communication link. The communication unit 21 communicably connects to the projector 10 by establishing a communication link with the projector 10 via a network NW according to the control by the control unit 24. The communication unit 21 may include, for example, an antenna that transmits and receives wireless signals, a receptacle into which a plug of a communication cable is inserted, and the like.

[0021] The input unit 22 is an input device that detects an input by a user and outputs a signal corresponding to the user's input to the control unit 24. At least any one of various input devices that can be adopted as the input device 112 can be adopted as the input unit 22.

[0022] The display unit 23 is a display that displays an image on a screen according to the control by the control unit 24. The display unit 23 is, for example, a flat panel display. The control unit 24 may transmit image data indicating an image to the projector 10 via the communication unit 21 so that the image D projected on the projector 10 is used as the image of the display unit 23. The input unit 22 and the display unit 23 may be configured as a touch panel display.

[0023] The control unit 24 includes a processing unit 25 and a storage unit 26. The processing unit 25 constitutes a processing device of a computer that processes operations necessary for the operation of the control device 20. The processing unit 25 realizes various functions of the control device 20 described in the embodiment by executing, for example, a program stored in the storage unit 26. As the processing device constituting at least a part of the processing unit 25, various logical operation circuits such as a CPU, a DSP, a PLD, and an ASIC can be adopted. The processing unit 25 may be constituted by integrated hardware or may be constituted by a plurality of separate hardwares.

[0024] The storage unit 26 is a computer-readable storage device that stores a program indicating a series of processes necessary for the operation of the control device 20 and various data. As the storage unit 26, for example, a semiconductor memory, various disk media, etc. can be adopted. The storage unit 26 is not limited to a non-volatile auxiliary storage device, and may include a volatile main storage device such as a register or a cache memory. At least a part of the storage unit 26 may be constituted by a part of the processing unit 25. The storage unit 26 may be constituted by integrated hardware, or may be constituted by a plurality of separate hardwares.

[0025] Hereinafter, with reference to the flowchart of FIG. 2, as an image projection method by the projection system 1, an example of a series of processes executed in the projection system 1 will be described. For example, the control circuit 12 prompts the user to adjust the installation state of the projector 10 by projecting an image corresponding to the maximum projection range via the projection device 13. Thereby, the installation state of the projector 10 can be adjusted in advance so that the image D is projected onto an arbitrary range on the screen SC.

[0026] In step S101, the projection device 13 projects a plurality of adjustment points defined relative to the image D as an adjustment point pattern onto the screen SC. The plurality of adjustment points are projected onto the screen SC as a plurality of grid points in a two-dimensional grid pattern. For example, the processing circuit 123 determines an adjustment point pattern in the initial state based on the basic information regarding image projection stored in the storage medium 124. The OSD processing circuit 121 generates the adjustment point pattern determined by the processing circuit 123 and projects it onto the screen SC via the projection device 13.

[0027] For example, as shown in FIG. 3, the projection device 13 has 16 adjustment points P arranged in a 4×4 matrix 11 ~P 14 ,P 21 ~P 24 ,P 31 ~P 34 ,P 41 ~P 44It is projected onto the screen SC as an adjustment point pattern in the initial state. The plurality of adjustment points are not limited to 4×4 and can be arranged in an n×m matrix. Each of n and m is an integer of 2 or more. The number of adjustment points can be set to any value according to the user input to the input I / F11 by editing the basic information in the storage medium 124.

[0028] In the example of FIG. 3, four adjustment points P 11 , P 14 , P 44 , P 41 form the four vertices of the rectangular image D. When a plurality of adjustment points P 11 ~P 44 are used as lattice points, among the plurality of unit regions defined by each lattice line indicated by the broken line, only the region surrounded by the sides E1~E4 shows the coordinate system of the pixels in the corresponding region of the image D as a fine lattice pattern. The side E1 is a line connecting between the adjacent adjustment points P 22 and the adjustment point P 23 . The side E2 is a line connecting between the adjacent adjustment points P 23 and the adjustment point P 33 . The side E3 is a line connecting between the adjacent adjustment points P 33 and the adjustment point P 32 . The side E4 is a line connecting between the adjacent adjustment points P 32 and the adjustment point P 22 . Here, "adjacent" means adjacent on the lattice line indicated by the broken line, that is, adjacent in the x-axis direction or the y-axis direction in the adjustment point pattern in the initial state shown in FIG. 3.

[0029] In step S102, the input I / F11 determines the positions of the plurality of adjustment points P 11 ~P 44 on the screen SC by detecting an input for adjusting the positions of the plurality of adjustment points P 11 ~P 44 . For example, the processing unit 25 displays a message on the display unit 23 requesting the user to arrange the positions of the adjustment points P 11 ~P 44 to match the shape of the projection surface, so that the user can adjust the adjustment points P 11~P 44 prompt to adjust the position of. The OSD processing circuit 121, for example, when the input I / F 11 detects a user input to the input unit 22, adjusts the positions of a plurality of adjustment points P 11 ~P 44 . For this reason, the display unit 23 can display an input screen having a plurality of points corresponding to the plurality of adjustment points P 11 ~P 44 . When the input I / F 11 detects an input that completes the adjustment of the positions of the plurality of adjustment points P 11 ~P 44 , the processing circuit 123 determines that the positions of the plurality of adjustment points P 11 ~P 44 are determined, and proceeds with the processing to step S103.

[0030] As shown in FIG. 4, the positions of the plurality of adjustment points P 11 ~P 44 can be arbitrarily adjusted from the initial positions according to the user's operations on the input unit 22 or the input device 112. For example, at least some of the positions of the plurality of adjustment points P 11 ~P 44 can be adjusted to correspond to the intersection points of the sides of the plane or the curved surface on a projection surface having unevenness due to a plurality of planes and a plurality of curved surfaces.

[0031] In step S103, the input I / F 11 determines the line type of each side by detecting an input for setting the line type of each of the plurality of sides connecting adjacent adjustment points. As the line type, for example, in addition to a straight line by linear interpolation (linear interpolation such as bilinear interpolation), various curves by non-linear interpolation (curve interpolation) such as polynomial interpolation, spline interpolation, and cubic interpolation can be set. For example, the processing unit 25 prompts to set the line type by displaying a message requesting to select the line type of each side on the display unit 23. The line type may be selected via the input unit 22 from a list displayed on the display unit 23, for example, or may be cyclically selected from predetermined options according to the operations on each side.

[0032] The processing circuit 123 determines whether each of the plurality of sides is a straight line or a curve according to the type of line set via the input I / F 11. At this time, the OSD processing circuit 121 may calculate the shape of each side according to the type of line determined in the processing circuit 123, and project each side onto the screen SC via the projector device 13. For example, when the type of line of side E1 shown in FIG. 3 is a straight line, the side F1 that is a straight line connecting the adjustment points P 22 ,P 23 can be projected. Similarly, when the type of line of side E2 is a straight line, the side F2 that is a straight line connecting the adjustment points P 23 ,P 33 is projected, and when the type of line of side E4 is a straight line, the side F4 that is a straight line connecting the adjustment points P 22 ,P 32 is projected. When the type of line of side E3 is a curve, the side G3 that is a curve connecting the adjustment points P 32 ,P 33 can be projected.

[0033] In the example shown in FIG. 4 and the like, the thick dashed line explains that the side G3 is a curve. For example, when determining the shape of side G3, the processing circuit 123 selects adjacent adjustment points on the grid line having side E3 as a part, and the number of adjustment points corresponds to the type of line set in step S103. For example, when the type of line is a quadratic curve, the processing circuit 123 selects at least the adjustment points P 31 ,P 32 ,P 33 or the adjustment points P 32 ,P 33 ,P 34 . If the type of line is a curve by bicubic interpolation, it is necessary to select at least 16 adjacent adjustment points. The processing circuit 123 determines the shape of side G3 by calculating a function indicating side G3 based on the positions of the selected adjustment points.

[0034] In step S104, the processing circuit 123 calculates the conversion coefficient in the non-linear interpolation according to the curve determined in step S103. That is, the processing circuit 123 calculates the conversion coefficient g(x, y) for obtaining the coordinates Dst(x, y) after interpolation from the initial coordinates Src(x, y) before interpolation of the image D according to the type of curve that means the type of interpolation method. The processing circuit 123 calculates the conversion coefficient g(x, y) for at least an area defined by four sides including a curve, such as an area A defined by a plurality of sides F1, F2, G3, F4 including the side G3 of the curve in FIG. 4. In the present embodiment, the area means a unit area. When the types of a plurality of curves are determined in step S103, the conversion coefficient g(x, y) may be calculated for each type of curve.

[0035] In step S105, the processing circuit 123 executes non-linear interpolation processing using the conversion coefficient g(x, y) calculated in step S104. That is, the processing circuit 123 generates a non-linear coordinate system by non-linear interpolation according to the type of curve determined in step S103 based on the positions of a plurality of adjustment points.

[0036] For example, as shown in FIG. 5, the processing circuit 123 generates non-linear coordinates by executing non-linear interpolation processing on a range corresponding to the area A of the adjustment point pattern. In this process, the sides F1, F2, F4 in FIG. 4 are replaced with the sides G1, G2, G4 that are curves respectively according to the line type of the side G3. That is, the range corresponding to the area A of the adjustment point pattern is understood as a non-linear coordinate system that is the result of non-linear interpolation, such as an area B defined by the sides G1, G2, G3, G4 that are curves respectively.

[0037] In step S106, the processing circuit 123 calculates the conversion coefficient in linear interpolation according to the straight line determined in step S103. That is, the processing circuit 123 calculates the conversion coefficient f(x, y) for obtaining the coordinates Dst(x, y) after interpolation from the initial coordinates Src(x, y) before interpolation of the image D according to the type of the straight line which means the type of the interpolation method. The processing circuit 123 calculates the conversion coefficient f(x, y) for at least the area defined by four sides including a straight line, such as the area A defined by a plurality of sides F1, F2, G3, F4 including the straight sides F1, F2, F4 in FIG. 4.

[0038] In step S107, the processing circuit 123 executes linear interpolation processing using the conversion coefficient f(x, y) calculated in step S105. That is, the processing circuit 123 generates a linear coordinate system by linear interpolation according to the type of the straight line determined in step S103 based on the positions of a plurality of adjustment points.

[0039] As shown in FIG. 6 for example, the processing circuit 123 generates a linear coordinate system by executing linear interpolation processing for the range corresponding to the area A of the adjustment point pattern. In this processing, the side G3 in FIG. 4 is replaced with a straight side F3 according to the line type of the sides F1, F2, F4. That is, the range corresponding to the area A of the adjustment point pattern is understood as a linear coordinate system which is the result of linear interpolation, such as the area C defined by the straight sides F1, F2, F3, F4 respectively.

[0040] In step S108, the processing circuit 123 synthesizes the interpolation results of steps S105 and S107 according to the line type determined in step S103. Here, an area defined by a plurality of sides including a straight line and a curve, such as the area A defined by the straight sides F1, F2, F4 and the curved side G3, is hereinafter referred to as a "specific area". The processing circuit 123 synthesizes the non-linear coordinate system and the linear coordinate system using the weighting according to the plurality of sides defining the specific area. Thereby, the processing circuit 123 generates the coordinate system of the specific area as the result of non-linear interpolation and linear interpolation.

[0041] For example, as shown in FIG. 7, the processing circuit 123 generates a coordinate system for area A defined by sides F1, F2, G3, and F4 by synthesizing a non-linear coordinate system such as area B in FIG. 5 and a linear coordinate system such as area C in FIG. 6. Specifically, the processing circuit 123 determines the weighting of the non-linear coordinate system and the linear coordinate system so as to realize sides F1, F2, F4 determined as straight lines and side G3 determined as a curve in step S103. The gradient of the weighting is, for example, linear, but can be arbitrarily determined.

[0042] In step S109, the geometric correction circuit 122 performs geometric correction of image D using the coordinate systems respectively generated in steps S105, S107, and S108. The geometric correction circuit 122 performs geometric correction so as to realize a plurality of sides defining the specific area for the image D in the range corresponding to the specific area by using the coordinate system of the specific area generated in step S108 as a result of the interpolation process.

[0043] Also, the geometric correction circuit 122 maintains the result of non-linear interpolation of area B defined only by the sides that are curves among the interpolation results obtained in steps S104 to S105 and employs it for geometric correction. That is, the geometric correction circuit 122 performs geometric correction so as to realize a plurality of curves defining area B for the image D in the range corresponding to area B. Similarly, the geometric correction circuit 122 maintains the result of linear interpolation of area C defined only by the sides that are straight lines among the interpolation results obtained in steps S106 to S107 and employs it for geometric correction. That is, the geometric correction circuit 122 performs geometric correction so as to realize a plurality of straight lines defining area C for the image D in the range corresponding to area C.

[0044] As described above, as shown in FIG. 8, the geometric correction circuit 122 performs geometric correction on the image D. In the example shown in FIG. 8, the three upper areas correspond to the area C defined only by the sides that are straight lines. The three middle areas correspond to the area A, that is, the specific area, defined by a plurality of sides including straight lines and curves. The three lower areas correspond to the area B defined only by the sides that are curves. In step S110, the projection device 13 projects the geometrically corrected image D onto the screen SC.

[0045] According to the projection system 1 according to the present embodiment, by determining whether each side connecting the adjustment points is a straight line or a curve with respect to the attribute of the side, interpolation processing can be performed using two types of interpolation methods: linear interpolation and curve interpolation. Therefore, according to the projection system 1, it is possible to perform appropriate geometric correction even for a projection surface having a complex shape formed by a plurality of planes and a plurality of curved surfaces.

[0046] As described above, as shown in the flowchart of FIG. 2, the case of using a plurality of types of interpolation methods including non-linear interpolation and linear interpolation in steps S104 to S108 has been described, but this is an example. That is, the projection system 1 may reduce the processing load by adopting only non-linear interpolation.

[0047] For example, as shown in the flowchart of FIG. 9, the projection system 1 may omit the linear interpolation process and the process of synthesizing the non-linear interpolation result and the linear interpolation result. Since the processes of steps S201 to S203 are substantially the same as the processes of steps S101 to S103 in FIG. 2, duplicate explanations are omitted.

[0048] In step S204, the processing circuit 123 defines virtual adjustment points by linear extrapolation for all the straight lines determined in step S203. In particular, the processing circuit 123 defines virtual curves by defining virtual adjustment points to be linearly extrapolated for the sides that are straight lines among the plurality of sides.

[0049] For example, as shown in FIG. 10, the processing circuit 123 selects all the straight edges F1, F2, and F4 among the plurality of edges F1, F2, G3, F4 that define area A, which is a specific area. The processing circuit 123 defines virtual adjustment points Q 21 , Q 24 that are linearly extrapolated on both sides of the edge F1. At the straight edge F1, the processing circuit 123 defines a straight line passing through the adjustment points P 22 , P 23 at both ends and the virtual adjustment points Q 21 , Q 24 as the virtual curve H1. That is, the virtual adjustment points Q 21 , Q 24 are temporarily used instead of the adjustment points P 21 , P 24 only as reference values for curve interpolation related to the edge F1.

[0050] Similarly, the processing circuit 123 defines virtual adjustment points Q 13 , Q 44 that are linearly extrapolated on both sides of the straight edge F2. At the edge F2, the processing circuit 123 defines a straight line passing through the adjustment points P 23 , P 33 at both ends and the virtual adjustment points Q 13 , Q 44 as the virtual curve H2. The virtual adjustment points Q 13 , Q 44 are temporarily used instead of the adjustment points P 13 , P 44 only as reference values for curve interpolation related to the edge F2. The processing circuit 123 defines virtual adjustment points Q 12 , Q 42 that are linearly extrapolated on both sides of the straight edge F4. At the edge F4, the processing circuit 123 defines a straight line passing through the adjustment points P 22 , P 32 at both ends and the virtual adjustment points Q 12 , Q 42 as the virtual curve H4. The virtual adjustment points Q 12 , Q 42 are temporarily used instead of the adjustment points P 12 , P 42 only as reference values for curve interpolation related to the edge F4.

[0051] In step S205, the processing circuit 123 calculates a conversion coefficient in non-linear interpolation based on the curve determined in step S203 and the virtual curve defined in step S204. That is, the processing circuit 123 calculates a conversion coefficient g(x, y) for obtaining the coordinates Dst(x, y) after interpolation from the initial coordinates Src(x, y) before interpolation of the image D according to the type of the curve. For a specific area defined by four sides including curves and straight lines, such as area A in FIG. 10, the processing circuit 123 calculates the conversion coefficient g(x, y) by treating a straight line as a virtual curve.

[0052] In step S206, the processing circuit 123 executes non-linear interpolation processing using the conversion coefficient g(x, y) calculated in step S205. That is, the processing circuit 123 generates a non-linear coordinate system by non-linear interpolation with reference to the curve determined in step S203 and the virtual curve defined in step S204. In particular, the processing circuit 123 generates a non-linear coordinate system for area A by non-linear interpolation with reference to side G3 which is a curve among a plurality of sides defining area A and all virtual curves H1, H2, H4.

[0053] In step S207, the geometric correction circuit 122 performs geometric correction of the image D using the coordinate system generated in step S206. The geometric correction circuit 122 performs geometric correction so as to realize a plurality of sides defining a specific area for the image D in a range corresponding to the specific area by using the coordinate system of the specific area as a result of the interpolation process. In step S208, the projection device 13 projects the geometrically corrected image D onto the screen SC.

[0054] Note that the virtual adjustment points can be determined, for example, as follows. In the example shown in FIG. 10, regarding the grid lines in the horizontal direction, let the coordinates of the virtual adjustment point Q 21 be h(x0, y0), the coordinates of the adjustment point P 22 be h(x1, y1), the coordinates of the adjustment point P 23 be h(x2, y2), and the coordinates of the virtual adjustment point Q 24 be h(x3, y3). At this time, the adjustment point P22 , P 23 The horizontal difference hdx and the vertical difference hdy of 23 are expressed as in Formula (1) and Formula (2), respectively. hdx = x2 - x1 …(1) hdy = y2 - y1 …(2)

[0055] Virtual adjustment point Q 21 The coordinates h(x0, y0) of 21 and the virtual adjustment point Q 24 The coordinates h(x3, y3) of 24 are calculated from Formula (3) to Formula (6). x0 = x1 - hdx …(3) y0 = y1 - hdy …(4) x3 = x2 + hdx …(5) y3 = y2 + hdy …(6)

[0056] On the other hand, regarding the vertical grid line, the coordinates of the virtual adjustment point Q 13 are v(x0, y0), the coordinates of the adjustment point P 23 are v(x1, y1), the coordinates of the adjustment point P 33 are v(x2, y2), and the coordinates of the virtual adjustment point Q 44 are v(x3, y3). At this time, the horizontal difference vdx and the vertical difference vdy of the adjustment point P 23 , P 33 are expressed as in Formula (7) and Formula (8), respectively. vdx = x2 - x1 …(7) vdy = y2 - y1 …(8)

[0057] Virtual adjustment point Q 13 The coordinates v(x0, y0) of 13 and the virtual adjustment point Q 24 The coordinates v(x3, y3) of 24 are calculated from Formula (9) to Formula (12). x0 = x1 - vdx …(9) y0 = y1 - vdy …(10) x3 = x2 + vdx …(11) y3 = y2 + vdy …(12)

[0058] As described above, since the virtual adjustment points are calculated by simple addition and subtraction, they can be easily defined for all sides that are straight lines. Therefore, according to the projection system 1 according to the modification of this embodiment, compared with the case of executing two types of interpolation methods, linear interpolation and non-linear interpolation, as shown in the flowchart of FIG. 2, the processing load can be significantly reduced.

[0059] According to the projection system 1 according to the modification of this embodiment, by determining whether the attribute of the side connecting the adjustment points is a straight line or a curve, the virtual adjustment points to be linearly extrapolated can be selectively defined for the straight line. Therefore, the projection system 1 can obtain a result equivalent to the result of geometric correction using multiple types of interpolation methods by performing curve interpolation with a straight line as a virtual curve. That is, according to the projection system 1, it is possible to perform appropriate geometric correction even for a projection surface having a complex shape.

[0060] [Other Embodiments] Although the embodiments have been described as above, the present invention is not limited to these disclosures. The configuration of each part may be replaced with any configuration having the same function, and within the technical scope of the present invention, any configuration in each embodiment may be omitted or added. Thus, various alternative embodiments will be apparent to those skilled in the art from these disclosures.

[0061] For example, in the flowchart of FIG. 2, the non-linear interpolation process in steps S104 and S105 may be executed after the linear interpolation process in steps S106 and S107. Also, in the flowchart of FIG. 9, the extrapolation process in step S204 may be executed after the calculation of the conversion coefficient in step S205. Specifically, as long as it is an interpolation method such as bicubic interpolation in which the coordinates of the virtual adjustment points do not affect the conversion coefficient, the virtual adjustment points may be defined after the calculation of the conversion coefficient. Thus, as long as the same geometric correction result as in this embodiment can be obtained, the processing order is not limited to the above.

[0062] In addition, the present invention naturally includes various embodiments not described above, such as configurations in which any of the configurations described in the above embodiments are applied to each other. The technical scope of the present invention is defined only by the invention-specific matters according to the reasonable claims based on the above description.

Explanation of Signs

[0063] 1... Projection system, 10... Projector, 11... Input I / F, 12... Control circuit, 13... Projection device, 20... Control device, 21... Communication unit, 22... Input unit, 23... Display unit, 24... Control unit, 25... Processing unit, 26... Storage unit, 30... Reproduction device, 111... Communication I / F, 112... Input device, 121... OSD processing circuit, 122... Geometric correction circuit, 123... Processing circuit, 124... Storage medium, 131... Light source, 132... Display panel, 133... Optical system.

Claims

1. Projecting a plurality of adjustment points defined for an image onto a screen; Detecting an input for determining the positions of the plurality of adjustment points on the screen, and determining the positions of the plurality of adjustment points based on the detected input; Detecting an input for setting whether each of a plurality of sides connecting adjacent adjustment points is a straight line or a curve, and determining whether each of the plurality of sides is a straight line or a curve based on the type; Performing geometric correction on the image corresponding to the area defined by the plurality of sides including the straight lines and the curves according to the determined straight lines and curves; And projecting the image subjected to the geometric correction onto the screen. An image projection method comprising the steps of:

2. Selecting, among the adjustment points corresponding to the type, the adjustment points adjacent to each other on a line having the side as a part, and determining the shape of the side based on the selected adjustment points. The image projection method according to claim 1.

3. The image projection method according to claim 1 or 2, wherein the plurality of adjustment points are projected onto the screen as a plurality of lattice points in a two-dimensional lattice pattern.

4. Further comprising generating a non-linear coordinate system of the area by non-linear interpolation and generating a linear coordinate system of the area by linear interpolation, and synthesizing the non-linear coordinate system and the linear coordinate system using weighting according to the plurality of sides defining the area, thereby performing geometric correction on the image corresponding to the area. The image projection method according to any one of claims 1 to 3.

5. Defining virtual adjustment points linearly extrapolated for all the straight lines among the plurality of sides defining the area; Defining, for each of all the straight lines, a straight line passing through the adjustment points at both ends and the virtual adjustment points as a virtual curve; and Generating a non-linear coordinate system of the area by non-linear interpolation with reference to all the curves and all the virtual curves among the plurality of sides defining the area, thereby performing geometric correction on the image corresponding to the area. The image projection method according to any one of claims 1 to 3.

6. A projection device that projects a plurality of adjustment points defined for an image onto a screen and projects the image onto the screen. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ An input for determining positions of the plurality of adjustment points on the screen, and the input An input interface that receives an input for determining whether each of a plurality of sides connecting the plurality of inputted adjustment points is a straight line or a curve ; and Based on the received input, a processing circuit that determines positions of the plurality of adjustment points and whether each of the plurality of sides connecting the plurality of adjustment points is the straight line or the curve ; and A correction circuit that performs geometric correction corresponding to a range corresponding to an area defined by the plurality of sides including the straight line and the curve on the image in accordance with the determined straight line and curve ; and A projector comprising the same

Images