JP5386883B2 - Projector and projector control method - Google Patents

Description

  The present invention relates to a projector that projects an image.

  In a projector that projects an image on a projection surface such as a screen, when the image is projected with the projector tilted with respect to the projection surface, the phenomenon that the image displayed on the projection surface is distorted in a trapezoidal shape (trapezoidal distortion) Arise. For this reason, there has been proposed a projector that detects the inclination (installation angle) of the projector and automatically corrects the trapezoidal distortion caused by the inclination (see, for example, Patent Document 1). In such a projector, when an image is formed in a pixel area including a large number of pixels, an image is formed in an area having a shape that can cancel the trapezoidal distortion, and pixels outside that area are formed. By invalidating the image, the image is displayed in a regular shape (rectangle).

  Here, when the inclination of the projector with respect to the projection surface is large, the trapezoidal distortion accompanying this becomes significant, and the number of pixels that should be invalidated during correction increases. That is, in this case, since the number of pixels that can be used for image formation is reduced, the image quality of the projected image is significantly deteriorated. For this reason, in the projector as described above, the range of the tilt that can correct the trapezoidal distortion is limited, and the correction of the trapezoidal distortion is performed only when the tilt of the projector is within this range.

  Patent Document 2 includes an angle sensor that detects the tilt angle of the projector, and when the detected tilt angle deviates from a predetermined range, the detected tilt angle is the largest among the tilt angles within the predetermined range. A projector that corrects trapezoidal distortion based on a close inclination angle and notifies that the inclination angle is outside a predetermined range has been proposed.

JP 2003-283963 A JP 2005-151028 A

  However, even if notified that the tilt angle is outside the predetermined range, users who are unfamiliar with the handling of the projector can immediately determine how to deal with the trapezoidal distortion sufficiently. It is difficult to do.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A projector according to this application example projects an image and displays the image on a projection surface, an inclination detection unit that detects an inclination of the projector with respect to the projection surface, and the inclination A trapezoidal distortion correction unit that performs trapezoidal distortion correction based on the inclination when the inclination detected by the detection unit is within a predetermined range; and the inclination detected by the inclination detection unit is outside the predetermined range. In this case, there is provided a guide unit that performs guidance for keeping the inclination within the predetermined range.

  According to this projector, when the inclination of the projector detected by the inclination detection unit is outside a predetermined range (a range in which the trapezoidal distortion can be corrected), the guide unit performs guidance for keeping within the range. It is possible to easily recognize a countermeasure to be taken to eliminate the trapezoidal distortion.

  Application Example 2 In the projector according to the application example, it is preferable that the guide unit guides a direction in which the projector should move.

  According to this projector, since the guide unit guides the direction in which the projector should move, it is possible to easily recognize in which direction the projector can be moved to eliminate the trapezoidal distortion.

  Application Example 3 In the projector according to the application example, it is preferable that the guide unit projects a guide image for performing the guidance from the image projection unit.

  According to this projector, the guide unit guides by using an image (guide image) projected from the image projection unit, so that the user can easily visually recognize the guide.

  Application Example 4 In the projector according to the application example described above, the trapezoidal distortion correction unit may detect an inclination within the predetermined range when the inclination detected by the inclination detection unit is outside the predetermined range. Of these, it is desirable to perform the trapezoidal distortion correction based on the inclination closest to the inclination detected by the inclination detecting unit.

  According to this projector, when the inclination of the projector is outside the predetermined range, the trapezoidal distortion correction unit corrects the image to eliminate the trapezoidal distortion when the inclination is within the predetermined range and is the nearest inclination. Therefore, it becomes possible to reduce the trapezoidal distortion as compared with the case where correction is not performed, and the visibility of the guide image can be improved.

  Application Example 5 In the projector according to the application example described above, it is preferable that the guide image includes a straight line that is horizontal or vertical when the trapezoidal distortion is eliminated.

  According to this projector, since the guide image projected by the guide unit includes a straight line that becomes horizontal or vertical when the trapezoidal distortion is eliminated, the projector is moved so that the straight line becomes horizontal or vertical. This makes it possible to eliminate trapezoidal distortion. In other words, the displayed straight line functions as a guide for keeping the inclination within a predetermined range, so that the convenience when moving the projector to eliminate the trapezoidal distortion is improved.

  Application Example 6 In the projector according to the application example described above, it is preferable that the guidance image includes a message representing the guidance, and the message is surrounded by a frame formed of the straight lines.

  Application Example 7 In the projector according to the application example described above, the tilt detection unit includes an imaging unit capable of capturing an image projected by the image projection unit, and detects the tilt based on an imaging result of the imaging unit. It is desirable.

  According to this projector, since the inclination detection unit detects the inclination of the projector based on the imaging result of the imaging unit, it is possible to easily detect not only the vertical direction but also the horizontal direction inclination.

Hereinafter, the projector according to the present embodiment will be described with reference to the drawings.
The projector modulates the light emitted from the light source to form an image based on image information input from the outside (hereinafter referred to as “input image”), and this image is applied to the surface (hereinafter referred to as “screen”, white board, etc.). , Which is called an “projection plane”). The projector according to the present embodiment has a trapezoidal distortion correction function, and can correct a trapezoidal distortion that occurs when an image is projected from an oblique direction with respect to the projection plane.

FIG. 1 is a block diagram illustrating a schematic configuration of the projector 1.
As shown in FIG. 1, the projector 1 includes an image projection unit 10, a control unit 20, a storage unit 21, an input operation unit 22, an imaging unit 23, an imaging data processing unit 24, an image information input unit 25, an image processing unit 26, An OSD processing unit 27, a trapezoidal distortion correction unit 28, and the like are provided.

  The image projection unit 10 includes a light source 11, three liquid crystal light valves 12 (12R, 12G, 12B) as a light modulation device, a projection lens 13 as a projection optical system, a light valve drive unit 14, and the like. The image projection unit 10 corresponds to a display unit, modulates the light emitted from the light source 11 with the liquid crystal light valve 12 to form an image (image light), and enlarges and projects this image from the projection lens 13. Display on the projection surface S.

  The light source 11 includes a discharge-type light source lamp 11a made of an ultrahigh pressure mercury lamp, a metal halide lamp, or the like, and a reflector 11b that reflects light emitted from the light source lamp 11a in a substantially constant direction. Light emitted from the light source 11 is converted into light having a substantially uniform luminance distribution by an integrator optical system (not shown), and red (R), green (G), and blue, which are the three primary colors of light, by a color separation optical system (not shown). After being separated into the color light components of (B), they are incident on the liquid crystal light valves 12R, 12G, and 12B, respectively.

  The liquid crystal light valve 12 is configured by a liquid crystal panel in which liquid crystal is sealed between a pair of transparent substrates. The liquid crystal light valve 12 is formed with a rectangular pixel region 12a composed of a plurality of pixels 12p arranged in a matrix, and a driving voltage can be applied to the liquid crystal for each pixel 12p. When the light valve driving unit 14 applies a driving voltage corresponding to the input image information to each pixel 12p, each pixel 12p is set to a light transmittance corresponding to the image information. For this reason, the light emitted from the light source 11 is modulated by transmitting through the pixel region 12a of the liquid crystal light valve 12, and an image corresponding to the image information is formed for each color light.

  The formed images of the respective colors are synthesized for each pixel 12p by a color synthesizing optical system (not shown) to form a color image, and then enlarged and projected onto the projection plane S by the projection lens 13. The projection lens 13 is provided with a zoom mechanism (not shown) for changing the enlargement ratio of the image, and the user can adjust the display size of the image with this zoom mechanism.

  In the present specification, the entire image projected from the projection lens 13 is referred to as a “projected image”. The projected image is a projection of an image formed in the entire area of the pixel area 12a. Even when the entire area or a part of the area of the pixel area 12a is black (a state in which almost no light is transmitted), A range including a part corresponding to the region is a projection image. Further, for example, when an image is projected onto the screen, even if a part of the image protrudes from the screen and is projected onto the rear wall surface or the like, a range including the protruding portion is a projected image.

  The control unit 20 includes a CPU (Central Processing Unit), a RAM (Random Access Memory) used for temporary storage of various data (not shown), and the like, according to a control program stored in the storage unit 21. By operating, the overall operation of the projector 1 is controlled. That is, the control unit 20 functions as a computer together with the storage unit 21.

  The storage unit 21 includes a non-volatile memory such as a mask ROM (Read Only Memory), a flash memory, or an FeRAM (Ferroelectric RAM). The storage unit 21 stores a control program for controlling the operation of the projector 1, various setting data for defining operation conditions of the projector 1, and the like.

  The input operation unit 22 includes a plurality of operation keys for the user to give various instructions to the projector 1. The operation keys provided in the input operation unit 22 include a power key for switching on / off of the power, a trapezoidal distortion correction key for instructing correction of trapezoidal distortion, and a determination key used for confirming various processes. Etc. When the user operates various operation keys of the input operation unit 22, the input operation unit 22 outputs an operation signal corresponding to the operation content of the user to the control unit 20. The input operation unit 22 may be configured using a remote control (not shown) capable of remote operation. In this case, the remote control transmits an infrared operation signal corresponding to the user's operation content, and a remote control signal receiving unit (not shown) receives this and transmits it to the control unit 20.

  The imaging unit 23 captures the front (projection direction of the image) of the projector 1, and includes an imaging element such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor, or the front of the imaging element. The imaging lens etc. which are arrange | positioned are provided. Based on an instruction from the control unit 20, the imaging unit 23 images a range including at least the projection image of the projection surface S, and as the imaging result, image data representing the captured image (captured image) (hereinafter “imaging”). Data "). The imaging data generated by the imaging unit 23 is output to the imaging data processing unit 24.

  The imaging data processing unit 24 performs various processes necessary for correcting the trapezoidal distortion based on the imaging data generated by the imaging unit 23. Specifically, the imaging data processing unit 24 recognizes the shape of the border (also referred to as “screen frame”) of the projection surface S in the captured image. Then, based on the shape of the screen frame, the inclination of the projector 1 with respect to the projection surface S is obtained, a shape capable of canceling the trapezoidal distortion due to the inclination is derived, and shape information representing the shape is obtained as a trapezoidal distortion correcting unit. To 28.

  The image information input unit 25 includes a connection terminal (not shown) for connection to an external image output device (not shown), and various types of image information (image signals) are input from the image output device. The The image information input unit 25 outputs the input image information to the image processing unit 26.

  The image processing unit 26 converts the various types of image information input from the image information input unit 25 into image information representing the gradation of each pixel 12p of the liquid crystal light valves 12R, 12G, and 12B. Here, the converted image information is classified by R, G, and B color lights, and is constituted by a plurality of pixel values corresponding to all the pixels 12p of the liquid crystal light valves 12R, 12G, and 12B. The pixel value defines the light transmittance of the corresponding pixel 12p, and the intensity (gradation) of light emitted from each pixel 12p is defined by this pixel value. In addition, the image processing unit 26 performs image quality adjustment processing for adjusting brightness, contrast, sharpness, hue, and the like on the converted image information based on an instruction from the control unit 20, and the processed image information Is output to the OSD processing unit 27.

  In addition, the image processing unit 26 can output image information (reference image information) for projecting a predetermined reference image (for example, a white plain image) based on an instruction from the control unit 20. When the control unit 20 instructs the projection of the reference image, the image processing unit 26 generates image information corresponding to the instruction regardless of the content of the image information input from the image information input unit 25, and the generated image information is displayed. The data is output to the OSD processing unit 27. For example, when the projection of the white plain reference image is instructed, the image processing unit 26 generates and outputs image information that maximizes the light transmittance of all the pixels 12p in the pixel region 12a. .

  The OSD processing unit 27 performs processing for superimposing an OSD (on-screen display) image such as a menu image or a message image on the input image based on an instruction from the control unit 20. The OSD processing unit 27 includes an OSD memory (not shown), and stores image data representing graphics, fonts, and the like for forming an OSD image. When the control unit 20 instructs to superimpose an OSD image, the OSD processing unit 27 reads out necessary image data from the OSD memory, and generates OSD image information for forming a specified OSD image. Then, the OSD image information is combined with the image information input from the image processing unit 26 so that the OSD image is superimposed at a predetermined position on the input image. The image information combined with the OSD image information is output to the trapezoidal distortion correction unit 28. If there is no instruction to superimpose the OSD image from the control unit 20, the OSD processing unit 27 outputs the image information input from the image processing unit 26 to the trapezoidal distortion correction unit 28 as it is.

  The trapezoidal distortion correction unit 28 corrects the image (image information) so as to eliminate the trapezoidal distortion that occurs when the projector 1 projects an image with respect to the projection plane S from an oblique direction. Specifically, the trapezoidal distortion correction unit 28 has an image forming region in the pixel region 12a of the liquid crystal light valve 12 that has a shape based on shape information input from the imaging data processing unit 24, that is, a shape that can cancel the trapezoidal distortion. Set. Then, the image information input from the OSD processing unit 27 is corrected so that the input image is formed in the image forming area. Further, the trapezoidal distortion correction unit 28 sets a black pixel value, that is, a pixel value that minimizes the light transmittance, for the pixel 12p outside the image forming area, in order to invalidate the area outside the image forming area. To do. The trapezoidal distortion correction unit 28 outputs the image information corrected as described above to the light valve driving unit 14. When there is no instruction to correct the trapezoidal distortion from the control unit 20, the trapezoidal distortion correcting unit 28 outputs the image information input from the OSD processing unit 27 to the light valve driving unit 14 as it is. In this case, an image based on the image information input from the OSD processing unit 27 is formed over the entire pixel region 12a.

  When the light valve driving unit 14 drives the liquid crystal light valve 12 according to the input image information, the liquid crystal light valve 12 forms an image according to the image information, and projects it from the projection lens 13 onto the projection surface S as a projection image. Is done.

Next, an outline of the trapezoidal distortion correction of the projector 1 will be described.
2 and 3 are explanatory diagrams for explaining the trapezoidal distortion. In each figure, (a) is a side view of the projector 1 and the projection surface S viewed from the side, and (b) is the projector 1 and FIG. FIG. 4C is a plan view of the projection surface S viewed from above, and FIG. In FIG. 2C and FIG. 3C, the screen frame F is indicated by a solid line, and the projected image Ao formed over the entire pixel area 12a is indicated by a broken line.

  2A and 2B, the projector 1 is not inclined with respect to the projection plane S, that is, the optical axis direction of the projection lens 13 is substantially the same as the normal direction of the projection plane S. In this state, as shown in FIG. 2C, trapezoidal distortion does not occur in the projected image Ao, and the projected image Ao is displayed in its original shape (rectangular shape). In this case, the input image only needs to be formed in the entire pixel area 12a, and therefore the user does not need to instruct correction of the trapezoidal distortion. For example, the projection image Ao is displayed in the full screen frame F of the projection surface S. As such, zoom adjustment, fine adjustment of the position of the projector 1, and the like may be performed as appropriate.

  On the other hand, as shown in FIGS. 3A and 3B, the projector 1 is inclined with respect to the projection plane S, that is, the optical axis direction of the projection lens 13 is the normal direction of the projection plane S. In different states, as shown in FIG. 3C, trapezoidal distortion occurs in the projected image Ao. In this case, the user can instruct correction of trapezoidal distortion by operating a keystone distortion correction key provided in the input operation unit 22. The angle formed by the optical axis of the projection lens 13 and the normal line of the projection surface S in a side view (refer to FIG. 3A) is referred to as “inclination angle θ in the vertical direction” and is viewed in plan view (FIG. 3B). The angle formed by the optical axis of the projection lens 13 and the normal line of the projection surface S is referred to as “the tilt angle φ in the left-right direction”.

FIG. 4 is an explanatory diagram for explaining processing for correcting trapezoidal distortion (trapezoidal distortion correction processing). FIG. 4A is a diagram illustrating a captured image captured by the imaging unit 23, and FIG. The figure which shows the pixel area | region 12a of the liquid crystal light valve 12 of the state which forms the image, (c) is a front view which shows the projection surface S. FIG.
When the user operates the keystone correction key, the projector 1 projects a white plain reference image, and in this state, the imaging unit 23 images the projection plane S (see FIG. 4A). The imaging data processing unit 24 obtains the inclination of the projector 1 with respect to the projection plane S, that is, the inclination angles θ and φ, based on the imaging result (captured image Pc), and can cancel the trapezoidal distortion caused by the inclination. , And shape information representing this shape is output to the trapezoidal distortion correction unit 28.

  The trapezoidal distortion correction unit 28 determines an image forming region 12e having a shape based on the input shape information (see FIG. 4B) in the pixel region 12a of the liquid crystal light valve 12, and is input from the OSD processing unit 27. The image information is corrected so that an image based on the image information (input image Pi) is formed in the image forming area 12e. That is, the input image Pi is formed in a distorted shape in the pixel region 12a. Furthermore, the trapezoidal distortion correction unit 28 sets the pixel 12p in the area outside the image forming area 12e (invalid area 12n) to a black pixel value. When the light valve driving unit 14 drives the liquid crystal light valve 12 based on the corrected image information, the distorted shape of the image forming region 12e (input image Pi) is canceled by the trapezoidal distortion, and the trapezoidal distortion is corrected. The input image Pi is displayed in the original shape (rectangular shape) (see FIG. 4C).

  Here, the trapezoidal distortion of the projected image Ao becomes more conspicuous as the inclination of the projector 1 with respect to the projection surface S is larger, that is, as the absolute values of the inclination angles θ and φ are larger, and image formation to be set in the pixel region 12a. The region 12e also needs to be greatly distorted. As a result, since the number of pixels 12p included in the image forming area 12e, that is, the number of pixels 12p forming the input image Pi, decreases, the resolution of the input image Pi decreases and the image quality deteriorates. Therefore, in the present embodiment, when the inclination of the projector 1 is within a predetermined range, that is, −α ≦ θ ≦ + α and −β ≦ φ ≦ + β (see FIGS. 3A and 3B). While the trapezoidal distortion correction process according to the tilt is performed, when the tilt of the projector 1 is outside the predetermined range, the projector 1 is instructed to the user in order to keep the tilt of the projector 1 within the predetermined range. A message to guide the movement is displayed. Note that the tilt angle ± α and the tilt angle ± β, which are limit values within a predetermined range, are also referred to as “limit tilt angles”.

  FIG. 5 is a flowchart for explaining in detail the operation of the projector 1 when the keystone correction key is operated. When the user operates the keystone correction key, the projector 1 operates according to the flow shown in FIG. Note that the position, tilt, and zoom state of the projector 1 are roughly adjusted by the user so that the projected image Ao includes the screen frame F of the projection surface S (see FIG. 3C).

  As shown in FIG. 5, in step S101, the control unit 20 instructs the image processing unit 26 to output reference image information for projecting a white plain reference image. When the light valve driving unit 14 drives the liquid crystal light valve 12 based on this reference image information, a reference image is formed over the entire pixel region 12a, and this reference image is projected from the projection lens 13 as a projection image Ao. As a result, the reference image (projected image Ao) is displayed on the projection surface S in a state where the trapezoidal distortion corresponding to the inclination of the projector 1 has occurred (see FIG. 3C).

  In step S102, the control unit 20 instructs the imaging unit 23 to image a range including the projection image Ao. The imaging unit 23 performs imaging in accordance with this instruction, and outputs the generated imaging data to the imaging data processing unit 24. The captured image Pc based on the captured data includes the projected image Ao and the screen frame F of the projection surface S (see FIG. 4A). Here, since the optical axis of the imaging lens provided in the imaging unit 23 and the optical axis of the projection lens 13 are both set in the front-rear direction, and both are substantially parallel, the projected image Ao is substantially the same in the captured image Pc. On the other hand, the screen frame F is distorted according to the inclination of the projector 1 with respect to the projection surface S. However, since the two optical axes are not strictly parallel, the projected image Ao is also slightly distorted in a trapezoidal shape. After finishing the imaging by the imaging unit 23, the control unit 20 causes the image processing unit 26 to stop outputting the reference image information and return to the state in which the input image Pi is projected.

  In step S <b> 103, the imaging data processing unit 24 analyzes the captured image Pc (for example, contour detection) based on the imaging data input from the imaging unit 23 and recognizes the shape of the screen frame F. Based on the shape (distortion) of the screen frame F, the inclination (inclination angles θ, φ) of the projector 1 is derived. Here, as a method of deriving the inclination of the projector 1 from the captured shape of the screen frame F, for example, the four sides of the screen frame F are extended, the intersection of the upper side and the lower side, the left side and the right side, It is possible to use a method of deriving the positions of two intersections (vanishing points) of the intersections and estimating the inclination angles θ and φ based on the positions of the vanishing points (see, for example, JP-A-2006-60447). ).

  In step S104, the imaging data processing unit 24 has the inclination of the projector 1 (derived inclination angles θ, φ) with respect to the projection plane S within a predetermined range (−α ≦ θ ≦ + α, −β ≦ φ ≦ + β). Determine whether or not. If the two inclination angles θ and φ are both within the predetermined range, the process proceeds to step S105. If at least one of the two inclination angles θ and φ is outside the predetermined range, step S105 is performed. The process proceeds to S107.

  When the inclination angles θ and φ are both within the predetermined range and the process proceeds to step S105, the imaging data processing unit 24 determines the shape of the image forming region 12e based on the derived inclination angles θ and φ. To do. Specifically, in order to cancel the trapezoidal distortion that may occur when an image is projected with the inclination angles θ and φ, the shape of the image forming area 12e with respect to the pixel area 12a is set in the captured image Pc (FIG. 4A )) To match the shape of the screen frame F with respect to the projected image Ao (see FIG. 4B). In the captured image Pc, when the distortion of the projected image Ao due to the deviation between the optical axis of the projection lens 13 and the optical axis of the imaging lens is so large that it cannot be ignored, a process (projection conversion) is performed to compensate for this. Etc.) may be performed as appropriate. The imaging data processing unit 24 outputs shape information corresponding to the determined shape of the image forming area 12e to the trapezoidal distortion correction unit 28 and notifies the control unit 20 that the inclination angles θ and φ are within a predetermined range. Notice.

  In step S106, the control unit 20 instructs the trapezoidal distortion correction unit 28 to set the image forming region 12e having a shape based on the shape information determined by the imaging data processing unit 24 in the pixel region 12a. Then, the correction of the image information is started to form the input image Pi in the image forming area 12e, and the flow ends. When the trapezoidal distortion correction unit 28 starts correcting the image information in response to this instruction, the input image Pi is projected from the image projection unit 10 with the keystone distortion corrected (see FIG. 4C).

  On the other hand, when at least one of the two inclination angles θ and φ is outside the predetermined range and the process proceeds to step S107, the imaging data processing unit 24 has the inclination angles θ and φ that are outside the predetermined range. Instead, the shape of the image forming area 12e is determined using the nearest limit inclination angles ± α, ± β of the inclination angles θ, φ. For example, when the inclination angle θ is within a predetermined range (−α ≦ θ ≦ + α) and the inclination angle φ is larger than the limit inclination angle + β, the imaging data processing unit 24 replaces the inclination angle φ. Using the limit inclination angle + β, the shape of the image forming region 12e is determined to be a shape that can cancel the trapezoidal distortion when an image is projected with the inclination angles θ and + β. When the tilt angle θ is larger than the limit tilt angle + α and the tilt angle φ is smaller than the limit tilt angle −β, image formation is performed using the limit tilt angles + α and −β instead of the tilt angles θ and φ. The shape of the region 12e is determined to be a shape that can cancel the trapezoidal distortion when the image is projected at the inclination angles + α and −β. The imaging data processing unit 24 outputs shape information corresponding to the determined shape to the trapezoidal distortion correction unit 28 and determines which tilt angle is out of a predetermined range in which direction (+ side or − side). The control unit 20 is notified as adjustment information. As a method of determining the shape of the image forming region 12e using the limit inclination angles ± α, ± β, for example, the vanishing point when the projector 1 images the screen frame F with the limit inclination angles ± α, ± β. The outline of the image forming region 12e may be configured by a straight line passing through the vanishing point (see, for example, Japanese Patent Application Laid-Open No. 2006-60447).

  6 to 9 are explanatory diagrams for explaining an example when the inclination of the projector 1 is out of a predetermined range. 6A is a side view of the projector 1 and the projection plane S viewed from the side, FIG. 6B is a plan view of the projector 1 and the projection plane S viewed from above, and FIG. 6C is the projection plane. FIG. 7A is a front view illustrating S, and FIG. 7A is a diagram illustrating a captured image Pc, and FIG. 7B is a diagram illustrating a pixel region 12 a of the liquid crystal light valve 12. FIG. 8 is a diagram illustrating a message image to be superimposed when the inclination of the projector 1 is outside a predetermined range. FIGS. 9A and 9B are diagrams when the message image is superimposed. 2 is a front view showing a projection surface S. FIG.

  As shown in FIGS. 6A and 6B, in this example, the vertical inclination angle θ is within a predetermined range (−α ≦ θ ≦ + α), while the horizontal inclination angle φ is It deviates to the + side with respect to a predetermined range (−β ≦ φ ≦ + β). For this reason, as shown in FIG. 6C, the projected image Ao has a trapezoidal distortion caused by the inclination angle φ as compared with the case where the inclination angle φ is within a predetermined range (see FIG. 3C). It appears prominently. In this case, the imaging data processing unit 24 derives the tilt angles θ and φ based on the captured image Pc captured by the imaging unit 23 (see FIG. 7A), and the tilt angle φ is greater than the limit tilt angle + β. And the shape of the image forming region 12e is determined to be a shape that can cancel the trapezoidal distortion when the image is projected at the inclination angles θ and + β (see FIG. 7B). Then, the imaging data processing unit 24 outputs adjustment information indicating that the inclination angle φ is deviated to the + side to the control unit 20.

  Returning to FIG. 5, in step S <b> 108, the control unit 20 indicates to the user the direction in which the projector 1 should move, that is, in which direction the projector 1 should move so that the inclination angles θ and φ are both within a predetermined range. For guidance, a message is superimposed on the OSD processing unit 27 based on the adjustment information input from the imaging data processing unit 24. For example, as in the example illustrated in FIG. 6, when adjustment information indicating that the horizontal inclination angle φ is deviated to the + side is input from the imaging data processing unit 24, that is, the projector 1 is in the projection plane S. When the image is projected from the right side to the left side, the control unit 20 instructs the OSD processing unit 27 to superimpose the message “Please move the projector to the left” (FIG. 8). For example, when adjustment information indicating that the vertical inclination angle θ is deviated to the + side is input, that is, the projector 1 projects an image upward from the lower side with respect to the projection surface S. In this case, the control unit 20 instructs the OSD processing unit 27 to superimpose a message “Move the projector upward.” When the adjustment information indicating that the inclination angles θ and φ are both deviated to the + side is input, the above two messages are displayed side by side. Based on the instruction from the control unit 20, the OSD processing unit 27 superimposes and displays a message image Pm including the instructed message and a frame (message frame Mf) surrounding the message as shown in FIG. Accordingly, the OSD image information is generated, and the OSD image information is superimposed on the image information input from the image processing unit 26. Here, the message frame Mf is composed of four straight lines (line segments) of an upper side, a lower side, a left side, and a right side, and the upper side and the lower side are horizontal with no trapezoidal distortion correction performed, and the left side and the right side. Is vertical. The message frame Mf is set to a size smaller than the image forming area 12e (input image Pi).

  In step S109, the control unit 20 instructs the trapezoidal distortion correction unit 28 to determine the shape based on the input shape information, that is, the imaging data processing unit 24 using the limit inclination angles ± α and ± β. The image forming area 12e having the shape is set in the pixel area 12a (see FIG. 7B), and correction of the image information is started to form the input image Pi in the image forming area 12e. When the trapezoidal distortion correction unit 28 starts correcting the image information in response to this instruction, the image projection unit 10 projects the input image Pi on which the message image Pm is superimposed (see FIG. 9A).

  Here, in the image forming area 12e determined in step S107, the nearest limit inclination angles ± α, ± β of the inclination angles θ, φ are used instead of the inclination angles θ, φ that are out of the predetermined range. Therefore, the trapezoidal distortion of the input image Pi is not sufficiently eliminated, and both the input image Pi and the message image Pm (message frame Mf) are displayed in a trapezoidal shape. In other words, if the projector 1 is moved so that the inclination angles θ and φ outside the predetermined range become the nearest limit inclination angles ± α and ± β, the input image Pi and the message frame Mf have the original shape (rectangular shape). The contour of the input image Pi and the upper and lower sides of the message frame Mf are horizontal, and the left and right sides are vertical. That is, when moving the projector 1 according to the message, the user can eliminate the trapezoidal distortion with a minimum movement amount by moving the input image Pi and the message frame Mf until they become rectangular.

  For example, as in the example shown in FIG. 6, when the inclination angle θ is within a predetermined range and the inclination angle φ is out of the predetermined range, as shown in FIG. The input image Pi is corrected for trapezoidal distortion in the vertical direction caused by the tilt angle θ, but is not sufficiently corrected for trapezoidal distortion in the horizontal direction caused by the tilt angle φ. In this state, when the user moves the projector 1 to the left according to the message and rotates the projector 1 slightly to the right (clockwise) so that the projection image Ao is projected toward the screen frame F, the input image Pi The message frame Mf is substantially rectangular at a position where the inclination angle φ becomes the limit inclination angle + β, and the trapezoidal distortion is eliminated (see FIG. 9B).

  The user can complete the trapezoidal distortion correction process by operating the enter key after moving the projector 1 to eliminate the trapezoidal distortion. That is, in step S110, the control unit 20 determines whether or not the enter key has been operated by the user. If the enter key is operated, the process proceeds to step S111. If the enter key is not operated, this step is repeated until the enter key is operated. In step S111, the control unit 20 instructs the OSD processing unit 27 to stop the superimposition of the message image Pm, and ends the flow. As a result, the input image Pi is displayed on the projection surface S with the trapezoidal distortion eliminated.

  As described above, according to the projector 1 of the present embodiment, the following effects can be obtained.

  (1) According to the projector 1 of the present embodiment, when the inclination of the projector 1 derived by the imaging data processing unit 24 is outside a predetermined range (a range in which trapezoidal distortion can be corrected), the control unit 20 The OSD processing unit 27 superimposes and displays the message image Pm, and performs guidance for keeping the tilt of the projector 1 within a predetermined range. For this reason, the user can easily recognize a countermeasure to be taken to eliminate the trapezoidal distortion.

  (2) According to the projector 1 of the present embodiment, the message image Pm superimposed by the OSD processing unit 27 indicates the direction in which the projector 1 should move in order to keep the inclination of the projector within a predetermined range. Therefore, the user can easily recognize in which direction the projector 1 can be moved to eliminate the trapezoidal distortion.

  (3) According to the projector 1 of the present embodiment, guidance for keeping the inclination of the projector 1 within a predetermined range by the message image Pm superimposed by the OSD processing unit 27, that is, an image projected from the image projection unit 10. Therefore, the user can easily visually recognize this guidance.

  (4) According to the projector 1 of the present embodiment, when the tilt angles θ and φ of the projector 1 are outside the predetermined range, the trapezoidal distortion correction unit 28 is the nearest limit tilt angle of the tilt angles θ and φ. Since the image is corrected so as to cancel the trapezoidal distortion when the image is projected at ± α, ± β, the trapezoidal distortion can be reduced as compared with the case where the correction is not performed, and the visibility of the message image Pm is improved. It becomes possible to do.

  (5) According to the projector 1 of the present embodiment, the message frame Mf of the message image Pm is rectangular when the inclination of the projector 1 is the limit inclination angles ± α, ± β, and at this time, the message frame Mf is configured. The straight line (line segment) is horizontal or vertical. Therefore, it is possible to eliminate the trapezoidal distortion by moving the projector 1 so that the message frame Mf is rectangular, that is, the straight line is horizontal or vertical. In other words, the message frame Mf functions as a guide for keeping the inclination of the projector 1 within a predetermined range, so that convenience when moving the projector 1 to eliminate the trapezoidal distortion is improved. Since the message frame Mf is set to a size smaller than the input image Pi, even when the input image Pi is projected so as to protrude from the screen frame F (see FIG. 9A), The message frame Mf is more likely to be projected inside the screen frame F. For this reason, it becomes possible to visually recognize the message frame Mf and the message written therein.

  (6) Since the projector 1 according to the present embodiment is configured to detect the inclination of the projector 1 based on the imaging result of the imaging unit 23, it is possible to easily detect not only the vertical direction but also the horizontal direction inclination. It becomes possible.

  In the present embodiment, the imaging unit 23 and the imaging data processing unit 24 correspond to an inclination detection unit. The message image Pm corresponds to a guidance image, and the control unit 20 and the OSD processing unit 27 when the message image Pm is superimposed correspond to a guidance unit.

(Modification)
Moreover, you may change the said embodiment as follows.

  The above embodiment shows a configuration that can correct both the vertical and horizontal trapezoidal distortions, but it can also be applied to a projector that can correct only one of the keystone distortions.

  In the above embodiment, in order to detect the inclination of the projector 1 with respect to the projection plane S, the imaging result (captured image Pc) of the imaging unit 23 is used. However, the means for detecting the inclination of the projector 1 is limited to this. For example, other detection means such as a gravity sensor or an optical sensor may be used.

  In the above embodiment, when imaging the projection surface S, a white plain reference image is projected, but the reference image to be projected is not limited to a white plain image, and other reference images may be used. In addition, a plurality of times of imaging may be performed using a plurality of reference images to improve the accuracy of analysis of the captured image Pc.

  In the above embodiment, only the moving direction of the projector 1 (direction to move) is shown in the message image Pm. For example, “Move the projector to the left and turn it slightly to the right”. As described above, the rotation direction of the projector 1 (direction to be rotated) may be written together. Further, when it is not necessary to fit an image in a predetermined screen frame F as in the case of projecting an image on a part of a large wall surface, only the rotation direction may be described.

  In the above embodiment, the message image Pm guides the direction in which the projector 1 should be moved with respect to the projection surface S such as a screen, but it is movable in front of the projector 1 whose position and orientation are fixed. When projecting an image with a screen installed, display a message that guides how to move the screen (moving direction, rotating direction, etc.), such as "Move the left edge of the screen to the back." You may do it.

  In the above embodiment, when the message image Pm is displayed, the image is projected by the image forming area 12e determined using the limit inclination angles ± α and ± β instead of the inclination angles θ and φ that are out of the predetermined range. The trapezoidal distortion of the image Ao (input image Pi) is corrected, but the trapezoidal distortion correction is performed only on the message image Pm, and the input image Pi on the background is not subjected to the trapezoidal distortion correction. Also good. Even in this case, the message frame Mf serves as a guideline for moving the projector 1, so that the convenience for the user is improved. Further, it is possible to adopt a mode in which even the message image Pm is not subjected to trapezoidal distortion correction.

  In the above embodiment, the message image Pm is composed of a message composed of characters and the message frame Mf, but the message frame Mf is not an essential configuration. Moreover, you may make it include images, such as an arrow and an illustration, instead of a message or with a message.

  In the above embodiment, the message frame Mf included in the message image Pm is a guideline for moving the projector 1, but a horizontal and / or vertical straight line (line segment) is included in the message image Pm. Thus, the same effect as the message frame Mf can be obtained.

  In the above embodiment, guidance for keeping the tilt of the projector 1 within a predetermined range is performed by the message image Pm superimposed on the projection image Ao by the OSD processing unit 27, but the present invention is not limited to this mode. For example, guidance may be provided by voice, or display means such as a liquid crystal display device may be provided in the projector 1 and a message may be displayed by this display means.

  In the above embodiment, the three-plate projector 1 using the three liquid crystal light valves 12R, 12G, and 12B as the light modulation device has been described. However, the aspect of the light modulation device is not limited to this. For example, it is possible to adopt an aspect in which an image is formed by one liquid crystal light valve including sub-pixels that can transmit R light, G light, and B light in each pixel 12p.

  In the above-described embodiment, the transmissive liquid crystal light valve 12 is used as the light modulator, but a reflective light modulator such as a reflective liquid crystal light valve may be used. Further, by controlling the emission direction of the incident light for each micromirror as the pixel 12p, a micromirror array device that modulates the light emitted from the light source 11 can be used.

  In the above embodiment, the light source 11 is configured by the discharge-type light source lamp 11a, but a solid light source such as an LED light source or other light sources can also be used.

FIG. 2 is a block diagram showing a schematic configuration of a projector. It is explanatory drawing for demonstrating trapezoid distortion, (a) is the side view which looked at the projector and the projection surface from the side, (b) is the top view which looked at the projector and the projection surface from the top, (c) FIG. 3 is a front view showing a projection surface. It is explanatory drawing for demonstrating trapezoid distortion, (a) is the side view which looked at the projector and the projection surface from the side, (b) is the top view which looked at the projector and the projection surface from the top, (c) FIG. 3 is a front view showing a projection surface. It is explanatory drawing for demonstrating a trapezoid distortion correction process, (a) is a figure which shows the captured image imaged by the imaging part, (b) is the pixel area | region of the liquid crystal light valve of the state which forms the image (C) is a front view which shows a projection surface. 7 is a flowchart for explaining in detail the operation of the projector when a keystone distortion correction key is operated. It is explanatory drawing for demonstrating an example when the inclination of a projector is outside a predetermined range, (a) is the side view which looked at the projector and the projection surface from the side, (b) is the projector and the projection surface The top view which looked at from the upper part, (c) is a front view which shows a projection surface. It is explanatory drawing for demonstrating an example when the inclination of a projector is outside a predetermined range, (a) is a figure which shows a captured image, (b) is a figure which shows the pixel area | region of a liquid crystal light valve. The figure which shows the message image superimposed when the inclination of a projector is outside a predetermined range. (A), (b) is explanatory drawing for demonstrating an example when the inclination of a projector is outside a predetermined range, and is a front view which shows the projection surface at the time of a message image being superimposed.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Projector, 10 ... Image projection part, 11 ... Light source, 12, 12R, 12G, 12B ... Liquid crystal light valve, 12a ... Pixel area, 12e ... Image formation area, 12n ... Invalid area | region, 12p ... Pixel, 13 ... Projection lens , 14: Light valve driving unit, 20 ... Control unit, 21 ... Storage unit, 22 ... Input operation unit, 23 ... Imaging unit, 24 ... Imaging data processing unit, 25 ... Image information input unit, 26 ... Image processing unit, 27 DESCRIPTION OF SYMBOLS ... OSD process part, 28 ... Trapezoid distortion correction part, Ao ... Projection image, F ... Screen frame, Mf ... Message frame, Pc ... Captured image, Pi ... Input image, Pm ... Message image, S ... Projection surface.

Claims (7)

A projector,
An image projection unit that projects an image and displays the image on a projection surface;
An inclination detector for detecting an inclination of the projector with respect to the projection plane;
A trapezoidal distortion correction unit that performs trapezoidal distortion correction based on the inclination when the inclination detected by the inclination detection unit is within a predetermined range;
A guide unit that performs guidance for keeping the tilt within the predetermined range when the tilt detected by the tilt detection unit is outside the predetermined range;
With
The guide unit projects a guide image for performing the guidance from the image projection unit,
The trapezoidal distortion correction unit uses the limit value of the predetermined range in a direction corresponding to the inclination when the inclination detected by the inclination detection unit is outside the predetermined range. A projector characterized by performing correction. The projector according to claim 1 ,
The tilt detection unit detects the tilt of the projector in a plurality of directions,
The trapezoidal distortion correction unit performs trapezoidal distortion correction based on the inclination of the projector in the plurality of directions, and the direction corresponding to the inclination in the direction in which the inclination is outside the predetermined range among the inclinations in the plurality of directions. For the projector, the trapezoidal distortion correction is performed using the limit value in the predetermined range . The projector according to claim 1 or 2 ,
The said guide part guides the direction which the said projector should move, The projector characterized by the above-mentioned. The projector according to any one of claims 1 to 3 ,
The projector according to claim 1, wherein the guide image includes a straight line that is horizontal or vertical when the trapezoidal distortion is eliminated. The projector according to claim 4 ,
The guidance image includes a message representing the guidance, and the message is surrounded by a frame formed by the straight lines. The projector according to any one of claims 1 to 5 ,
The projector according to claim 1, wherein the tilt detection unit includes an imaging unit capable of capturing an image projected by the image projection unit, and detects the tilt based on an imaging result of the imaging unit. A method for controlling a projector that projects an image and displays the image on a projection surface,
The projector detects an inclination of the projector with respect to the projection plane;
When the detected inclination is within a predetermined range, the projector performs trapezoidal distortion correction based on the inclination,
When the detected inclination is outside the predetermined range, the projector performs guidance for keeping the inclination within the predetermined range,
Projecting a guidance image for performing the guidance,
When the detected inclination is outside the predetermined range, the trapezoidal distortion correction is performed using a limit value of the predetermined range in a direction corresponding to the inclination. .

Images