JP6103855B2 - Projection apparatus, control method therefor, program, and storage medium - Google Patents

Description

  The present invention relates to a projection apparatus, a control method therefor, a program, and a storage medium.

  2. Description of the Related Art Conventionally, as a technique for distortion correction of a projection apparatus, a technique is known in which distortion correction is performed by deforming a projection image in accordance with a movement instruction of four corner points of the projection image from a user. However, since this technique cannot move the four corner points outside the projection image, the user has to install the projection device in advance so that the projection image includes the screen before distortion correction.

  For example, Patent Document 1 and Patent Document 2 disclose the following techniques for this problem. First, before the distortion is corrected, the projection direction is photographed by the imaging unit, and the positional relationship between the projection area and the projection image is recognized. Next, calculate the zoom condition where the outer periphery of the projected image is not located within the screen area and the projected image becomes as small as possible, drive the zoom lens to satisfy the condition, and then deform the image Then, distortion correction of the projected image is performed.

Japanese Patent No. 4578341 JP 2006-121240 A

  However, the techniques described in Patent Document 1 and Patent Document 2 require an imaging unit for recognizing the projection area before distortion correction, which causes a cost increase. In addition, when the projection area cannot be identified from the captured image, such as when projecting onto a plain wall, distortion correction cannot be performed appropriately.

  The present invention has been made in view of the above problems, and an object of the present invention is to distort a projection image into an appropriate size and shape without using an imaging unit and regardless of the positional relationship between the projection image before distortion correction and the projection region. A projection apparatus capable of performing correction and a control method thereof are realized.

In order to solve the above-described problems and achieve the object, an imaging apparatus according to the present invention includes a projection unit that projects an image on a projection plane, and a plurality of correction points in the image projected on the projection plane in response to a user operation. A setting means for moving the position; a deformation means for deforming the shape of the projected image according to the position of the correction point set by the setting means; and a projection range by the projection means optically by zooming. a correction correcting means, when the position corresponding to the plurality of correction points in the projected image after deformation by the deforming means is inside the projection range, the correction means so that to reduce the projection range Control means for controlling.

  According to the present invention, when the user determines the position of the correction point of the projection image during distortion correction, the zoom operation is performed, and the projection image is reduced as much as possible while maintaining the relationship including the target projection position. Accordingly, the projected image is corrected for distortion. Therefore, it is possible to correct the distortion of the projection image to an appropriate size and shape without using an imaging unit, regardless of the positional relationship between the projection image before distortion correction and the projection area.

The figure which shows the structure of the projection apparatus of embodiment which concerns on this invention. 6 is a flowchart showing the basic operation of the projector according to the present embodiment. FIG. 3 is a diagram illustrating an internal configuration of an image processing unit according to the first embodiment. 5 is a flowchart illustrating a deformation process according to the first embodiment. FIG. 4 is a diagram for explaining deformation processing by comparing a projection area on the liquid crystal panel according to the first embodiment with a projection area projected on a screen. FIG. 6 is a diagram for explaining deformation processing according to the first embodiment. 10 is a flowchart showing deformation processing according to the second embodiment. The figure explaining projective transformation. The flowchart which shows the modification in S406 of FIG. FIG. 6 is a diagram for explaining deformation processing according to the second embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. The embodiment described below is an example for realizing the present invention, and should be appropriately modified or changed according to the configuration and various conditions of the apparatus to which the present invention is applied. It is not limited to the embodiment. Moreover, you may comprise combining suitably one part of each embodiment mentioned later.

  [Embodiment 1] An embodiment in which the present invention is applied to, for example, a liquid crystal projector for projecting an image will be described below.

  <Apparatus Configuration> With reference to FIG. 1, an outline of the configuration and functions of a projection apparatus according to an embodiment of the present invention will be described.

  The liquid crystal projector of the present embodiment (hereinafter abbreviated as “projector”) controls the light transmittance of the liquid crystal element according to the image to be displayed, and projects the light from the light source that has passed through the liquid crystal element onto the screen. Thus, the image is presented to the user.

  In FIG. 1, the projector 100 according to the present embodiment includes a CPU 110, a ROM 111, a RAM 112, an operation unit 113, an image input unit 130, and an image processing unit 140. The projector 100 also includes a liquid crystal control unit 150, liquid crystal elements 151R, 151G, and 151B, a light source control unit 160, a light source 161, a color separation unit 162, a color composition unit 163, an optical system control unit 170, and a projection optical system 171. Further, the projector 100 may include a recording / playback unit 191, a recording medium 192, a communication unit 193, an imaging unit 194, a display control unit 195, and a display unit 196.

  CPU 110 controls each operation block of projector 100. The ROM 111 stores a control program that describes the processing procedure of the CPU 110. The RAM 112 temporarily stores control programs and data as work memory. In addition, the CPU 110 temporarily stores still image data and moving image data reproduced from the recording medium 192 by the recording / reproducing unit 191, and reproduces each image and video using a program stored in the ROM 111. You can also In addition, the CPU 110 can temporarily store still image data and moving image data received from the communication unit 193, and can reproduce each image or video using a program stored in the ROM 111. In addition, an image or video obtained by the imaging unit 194 can be temporarily stored in the RAM 112, converted into still image data or moving image data using a program stored in the ROM 111, and recorded on the recording medium 192. .

  The operation unit 113 includes, for example, a switch, a dial, a touch panel provided on the display unit 196, and the like. The operation unit 113 receives a user instruction and transmits an instruction signal to the CPU 110. For example, the operation unit 113 may be a signal reception unit (such as an infrared reception unit) that receives a signal from a remote controller (not shown) and transmits a predetermined instruction signal to the CPU 110 based on the received signal. Good. In addition, the CPU 110 receives control signals input from the operation unit 113 and the communication unit 193 and controls each operation block of the projector 100.

  The image input unit 130 receives an image signal and a video signal from an external device. The image input unit 130 includes, for example, a composite terminal, an S video terminal, a D terminal, a component terminal, an analog RGB terminal, a DVI-I terminal, a DVI-D terminal, an HDMI (registered trademark) terminal, and the like. In addition, when receiving an analog image signal or video signal, the image input unit 130 converts the received analog signal into a digital signal and transmits the digital signal to the image processing unit 140. Here, the external device may be any device such as a personal computer, a camera, a mobile phone, a smartphone, a hard disk recorder, or a game machine as long as it can output an image signal and a video signal.

  The image processing unit 140 includes, for example, a microprocessor for image processing. The image processing unit 140 performs processing for changing the number of frames, the number of pixels, the image shape, and the like on the image signal and the video signal received from the image input unit 130, and Send. Further, the image processing unit 140 does not need to be a dedicated microprocessor. For example, the CPU 110 may execute the same processing as the image processing unit 140 by a program stored in the ROM 111. The image processing unit 140 can execute functions such as frame thinning processing, frame interpolation processing, resolution conversion processing, and distortion correction processing (keystone correction processing). In addition to the signal received from the image input unit 130, the image processing unit 140 can also perform the above-described change processing on the image or video reproduced by the CPU 110. Specific behavior regarding the distortion correction processing by the image processing unit 140 will be described later.

  The liquid crystal control unit 150 includes, for example, a control microprocessor, and applies to the liquid crystal of the pixels of the liquid crystal elements 151R, 151G, and 151B of each liquid crystal panel based on the image signal and the video signal processed by the image processing unit 140. The transmittance of the liquid crystal elements 151R, 151G, and 151B is adjusted by controlling the voltage. Note that the liquid crystal control unit 150 does not have to be a dedicated microprocessor. For example, the CPU 110 may execute the same processing as the liquid crystal control unit 150 by a program stored in the ROM 111. For example, when a video signal is input to the image processing unit 140, the liquid crystal control unit 150 causes the liquid crystal element to have a transmittance corresponding to the image every time an image of one frame is received from the image processing unit 140. 151R, 151G, and 151B are controlled. The liquid crystal element 151 </ b> R is a liquid crystal element corresponding to red, and out of the light output from the light source 161, the light separated into red (R), green (G), and blue (B) by the color separation unit 162. Among them, the transmittance of red light is adjusted. The liquid crystal element 151 </ b> G is a liquid crystal element corresponding to green, and out of the light output from the light source 161, the light separated into red (R), green (G), and blue (B) by the color separation unit 162. Among them, the transmittance of green light is adjusted. The liquid crystal element 151 </ b> B is a liquid crystal element corresponding to blue, and of the light output from the light source 161, the light separated into red (R), green (G), and blue (B) by the color separation unit 162. Among them, the transmittance of blue light is adjusted.

  The light source control unit 160 includes, for example, a control microprocessor that controls on / off of the light source 161 and the amount of light. Note that the light source control unit 160 does not have to be a dedicated microprocessor. For example, the CPU 110 may execute the same processing as the light source control unit 160 by a program stored in the ROM 111. The light source 161 is, for example, a halogen lamp, a xenon lamp, or a high-pressure mercury lamp, and outputs light for projecting an image on the screen 180. The color separation unit 162 includes, for example, a dichroic mirror and a prism, and separates light output from the light source 161 into red (R), green (G), and blue (B). In addition, when using LED etc. corresponding to each color as the light source 161, the color separation part 162 is unnecessary. The color composition unit 163 is composed of, for example, a dichroic mirror or a prism, and synthesizes red (R), green (G), and blue (B) light transmitted through the liquid crystal elements 151R, 151G, and 151B. Then, light obtained by combining the red (R), green (G), and blue (B) components by the color combining unit 163 is sent to the projection optical system 171. At this time, the liquid crystal elements 151 </ b> R, 151 </ b> G, and 151 </ b> B are controlled by the liquid crystal control unit 150 so as to have a light transmittance corresponding to the image input from the image processing unit 140. Therefore, when the light combined by the color combining unit 163 is projected onto the screen by the projection optical system 171, an image corresponding to the image input by the image processing unit 140 is displayed on the screen.

  The optical system control unit 170 is composed of a control microprocessor, for example, and controls the projection optical system 171. The optical system control unit 170 does not need to be a dedicated microprocessor. For example, the CPU 110 may execute the same processing as the optical system control unit 170 by a program stored in the ROM 111. The projection optical system 171 projects the combined light output from the color combining unit 163 onto the screen. The projection optical system 171 includes a plurality of lenses and lens driving actuators. By driving the lenses with the actuators, the projection image can be enlarged, reduced, shifted, and focused.

  The recording / reproducing unit 191 reproduces still image data and moving image data from the recording medium 192, and receives still image data and moving image data obtained by the imaging unit 194 from the CPU 110 and records them on the recording medium 192. Still image data and moving image data received from the communication unit 193 may be recorded on the recording medium 192. The recording / reproducing unit 191 includes, for example, an interface electrically connected to the recording medium 192 and a microprocessor for communicating with the recording medium 192. Note that the recording / reproducing unit 191 does not need to include a dedicated microprocessor. For example, the CPU 110 may execute the same processing as the recording / reproducing unit 191 by a program stored in the ROM 111. The recording medium 192 can record still image data, moving image data, and other control data necessary for the projector according to the present embodiment. The recording medium 192 may be any type of recording medium such as a magnetic disk, an optical disk, or a semiconductor memory, and may be a detachable recording medium or a built-in recording medium.

  The communication unit 193 is for receiving control signals, still image data, moving image data, and the like from an external device. For example, the communication unit 193 may be a wireless LAN, a wired LAN, USB, Bluetooth (registered trademark), or the like. The method is not particularly limited. Further, if the terminal of the image input unit 130 is, for example, an HDMI (registered trademark) terminal, CEC communication may be performed via the terminal. Here, the external device may be any device such as a personal computer, a camera, a mobile phone, a smartphone, a hard disk recorder, a game machine, and a remote controller as long as it can communicate with the projector 100.

  The display control unit 195 includes a display control microprocessor or the like, and controls the display unit 196 provided in the projector 100 to display an image such as an operation screen for operating the projector 100 or a switch icon. Note that the display controller 195 need not be a dedicated microprocessor. For example, the CPU 110 may execute the same processing as the display controller 195 by a program stored in the ROM 111. The display unit 196 displays an operation screen and a switch icon for operating the projector 100. The display unit 196 may be anything as long as it can display an image. For example, it may be a liquid crystal display, a CRT display, an organic EL display, or an LED display. Further, in order to post a specific button so that the user can recognize it, an LED or the like corresponding to each button may be made to emit light.

  Note that the image processing unit 140, the liquid crystal control unit 150, the light source control unit 160, the optical system control unit 170, the recording / playback unit 191, and the display control unit 195 according to the present embodiment perform processing similar to these operation blocks. There may be one or more possible microprocessors. Alternatively, for example, the CPU 110 may execute the same processing as that of each block by a program stored in the ROM 111.

  <Basic Operation> Next, the basic operation of the projector 100 of this embodiment will be described with reference to FIG. 1 and FIG.

  FIG. 2 is a flowchart showing the basic operation of the projector 100 of the present embodiment. The operation of FIG. 2 is realized by the CPU 110 developing a program stored in the ROM 111 in the work area of the RAM 112 and controlling each operation block. The operation in FIG. 2 is started when the user turns on the power of the projector 100 using the operation unit 113 or the remote controller. When the user turns on the power of the projector 100 using the operation unit 113 or the remote controller, the CPU 110 starts supplying power from a power supply unit (not shown) to each unit of the projector 100 by a power supply control unit (not shown).

  Next, the CPU 110 determines the display mode selected by the operation of the operation unit 113 or the remote controller by the user (S210). One display mode of the projector 100 according to the present embodiment is an “input image display mode” in which an image or video input from the image input unit 130 is displayed. In addition, one of the display modes of the projector 100 according to the present embodiment is a “file playback display mode” in which still image data or moving image data read from the recording medium 192 by the recording / playback unit 191 is displayed. In addition, one of the display modes of the projector 100 according to the present embodiment is a “file reception display mode” in which still image data and moving image data received from the communication unit 193 are displayed. In this embodiment, the case where the display mode is selected by the user will be described. However, the display mode at the time of turning on the power may be the display mode at the end of the previous time. These display modes may be set as the default display mode. In that case, the process of S210 can be omitted.

  Here, it is assumed that “input image display mode” is selected in S210.

  When the “input image display mode” is selected, the CPU 110 stands by until an image or video is input from the image input unit 130 (S220). Then, if input (Yes in S220), the process proceeds to the projection process (S230).

  In S230, the CPU 110 transmits the image or video input from the image input unit 130 to the image processing unit 140, and causes the image processing unit 140 to change the number of pixels of the image or video, the frame rate, and the shape, and perform processing. The image for one screen to which the above is applied is transmitted to the liquid crystal control unit 150. Then, the CPU 110 causes the liquid crystal control unit 150 to have a transmittance corresponding to the gradation level of each color component of red (R), green (G), and blue (B) of the received image for one screen. The transmittance of the liquid crystal elements 151R, 151G, and 151B of each liquid crystal panel is controlled. Then, the CPU 110 controls the output of light from the light source 161 by the light source control unit 160. The color separation unit 162 separates the light output from the light source 161 into red (R), green (G), and blue (B), and separates each light into the liquid crystal elements 151R, 151G, and 151B of each liquid crystal panel. Supply. The amount of light of each color supplied to each liquid crystal element 151R, 151G, 151B is limited for each pixel of each liquid crystal element. The red (R), green (G), and blue (B) lights transmitted through the liquid crystal elements 151R, 151G, and 151B are supplied to the color synthesis unit 163 and synthesized again. The light synthesized by the color synthesis unit 163 is projected onto the screen 180 via the projection optical system 171.

  This projection processing is sequentially executed for each image of one frame while the image is projected.

  At this time, when an operation instruction for the projection optical system 171 is input from the operation unit 113 by the user, the CPU 110 causes the optical system control unit 170 to change the focus of the projection image or change the magnification ratio of the optical system. The actuator of the projection optical system 171 is controlled so that it does.

  During execution of the display process, the CPU 110 determines whether or not an instruction to switch the display mode is input from the operation unit 113 by the user (S240). When an instruction to switch the display mode is input from the operation unit 113 (Yes in S240), the CPU 110 returns to S210 again and determines the display mode. At this time, the CPU 110 transmits, to the image processing unit 140, a menu screen for selecting a display mode as an OSD (On Screen Display) image, and the OSD screen is superimposed on the image being projected. The processing unit 140 is controlled. The user selects a display mode while viewing the projected OSD screen.

  On the other hand, when an instruction to switch the display mode is not input from the operation unit 113 by the user during display processing (No in S240), the CPU 110 determines whether an instruction to end projection is input from the operation unit 113 by the user. Determination is made (S250). If an instruction to end projection is input from the operation unit 113 (Yes in S250), the CPU 110 stops power supply to each operation block of the projector 100 and ends the projection process. On the other hand, when a projection end instruction is not input from the operation unit 113 (No in S250), the CPU 110 returns to S220, and thereafter, from S220 to S250 until a projection end instruction is input from the operation unit 113. Repeat the process.

  As described above, the projector 100 according to the present embodiment projects an image on the screen.

  In the “file playback display mode”, the CPU 110 reads out a file list of still image data and moving image data and thumbnail data of each file from the recording medium 192 by the recording / playback unit 191 and temporarily stores them in the RAM 112. Then, based on the program stored in the ROM 111, the CPU 110 generates a character image based on the file list temporarily stored in the RAM 112 and an image based on the thumbnail data of each file, and transmits the image to the image processing unit 140. Then, the CPU 110 controls the image processing unit 140, the liquid crystal control unit 150, and the light source control unit 160 in the same manner as the normal projection processing (S230).

  Next, an instruction to select characters and images corresponding to still image data and moving image data recorded on the recording medium 192 on the projection screen is input via the operation unit 113. Then, the CPU 110 controls the recording / reproducing unit 191 so as to read out selected still image data and moving image data from the recording medium 192. The CPU 110 temporarily stores the read still image data and moving image data in the RAM 112, and reproduces the image and video of the still image data and moving image data based on the program stored in the ROM 111.

  Then, for example, the CPU 110 sequentially transmits the reproduced moving image data to the image processing unit 140, and controls the image processing unit 140, the liquid crystal control unit 150, and the light source control unit 160 in the same manner as the normal projection processing (S230). To do. When the still image data is reproduced, the reproduced image is transmitted to the image processing unit 140, and the image processing unit 140, the liquid crystal control unit 150, and the light source control unit 160 are transmitted in the same manner as the normal projection processing (S230). Control.

  In the “file reception display mode”, the CPU 110 temporarily stores still image data and moving image data received by the communication unit 193 in the RAM 112, and stores the still image data and moving image data based on the program stored in the ROM 111. Reproduce. For example, the CPU 110 sequentially transmits the reproduced moving image data to the image processing unit 140, and controls the image processing unit 140, the liquid crystal control unit 150, and the light source control unit 160 in the same manner as the normal projection processing (S230). When the still image data is reproduced, the reproduced image is transmitted to the image processing unit 140, and the image processing unit 140, the liquid crystal control unit 150, and the light source control unit 160 are transmitted in the same manner as the normal projection processing (S230). Control.

  <Configuration of Image Processing Unit> Next, the configuration of the image processing unit of this embodiment will be described with reference to FIG.

  In FIG. 3, the image processing unit 140 includes a signal processing unit 310, an OSD superimposing unit 320, and a deformation processing unit 330.

  As described above, the original image signal s301 is input from the image input unit 130, the recording / reproducing unit 191, or the communication unit 193 according to the display mode. The timing signal s302 is a vertical synchronization signal, a horizontal synchronization signal, a clock, or the like that is synchronized with the original image signal s301, and is supplied from the source of the original image signal s301. Each block in the image processing unit 140 operates based on the timing signal s302. However, the timing signal may be regenerated and used inside the image processing unit 140.

  The signal processing unit 310 cooperates with the CPU 110 to acquire statistical information such as a histogram and APL of the image signal, IP conversion, frame rate conversion, resolution conversion, γ conversion, color gamut conversion, and the like for the original image signal s301. Perform signal processing such as color correction and edge enhancement. The processed image signal s303 processed by the signal processing unit 310 is output to the OSD superimposing unit 320.

  The OSD superimposing unit 320 superimposes a menu for a user and guide information for operation as an OSD image on the processed image signal s303 in accordance with an instruction from the CPU 110, and outputs the generated OSD superimposed signal s304 to the deformation processing unit 330. .

  The deformation processing unit 330 obtains the coordinates of the pixels before and after the deformation based on a predetermined deformation formula, performs a deformation process on the OSD superimposed signal s304, and outputs a post-deformation image signal s305.

  The deformation processing unit 330 in the present embodiment is assumed to deform an image using projective transformation, and this deformation processing will be described below with reference to FIG.

  In FIG. 8, 810 indicates an image before distortion correction (original image) having four points Ps1 to Ps4 as vertices, and 820 indicates an image after distortion correction having four points Pd1 to Pd4 as vertices.

  In the projective transformation, the relationship between the coordinates (xs, ys) of the original image 810 and the coordinates (xd, yd) of the transformed image 820 is expressed by the following formula 1.

  M is a 3 × 3 projective transformation matrix from the post-deformation image to the original image, and is input from the CPU 110 to the deformation processing unit 330. xs1 and ys1 are the coordinates of one vertex Ps1 of the original image 810, and xd1 and yd1 are the coordinate values of the vertex Pd1 of the transformed image 820.

  If the coordinates (xs, ys) of the original image obtained by Equation 1 above are integers, this may be used as the pixel value of the coordinates (xd, yd) of the transformed image. However, the coordinates of the original image obtained by Equation 1 are not always integers. In this case, the pixel value of the post-deformation coordinates (xd, yd) is obtained by interpolation using the pixel values of the surrounding pixels of the coordinates of the original image. The interpolation method may be bilinear, bicubic, or any other interpolation method. When the coordinates of the original image obtained based on Expression 1 are outside the range of the original image 810, the pixel value is black or the background color set by the user.

  The deformation processing unit 330 creates a post-deformation image by obtaining pixel values for all the post-deformation coordinates in the above procedure.

  In the above example, the projective transformation matrix M is input from the CPU 110 to the deformation processing unit 330. However, the projective transformation matrix M may be obtained inside the image processing unit 140. The projective transformation matrix M is uniquely obtained from the four corner points of the original image and the four corner points of the coordinates of the transformed image. Since this method is publicly known, its details are omitted.

  As described above, the post-deformation image signal s305 output from the deformation processing unit 330 is supplied to the liquid crystal control unit 150 and displayed on the liquid crystal panel.

  <Distortion Correction Processing & Zooming Operation> Next, with reference to FIGS. 4 to 6, the distortion correction processing by the projector 100 of this embodiment will be described.

  5A and 5B show the projected area of the liquid crystal panel and the projected area projected onto the projection surface, with FIG. 5A showing the projected image on the liquid crystal panel and FIG. 5B showing the projected image on the screen. A representative liquid crystal panel is shown.

  When the entire surface of the liquid crystal panel is used as a projection area 510 and is projected on the screen, when the projector 100 and the screen are not relatively facing each other, the shape varies depending on the tilt angle and optical conditions, but the projected image on the screen is It becomes a distorted square like 520. P1 to P4 are the four corners of the projection area on the liquid crystal panel, and are moved as correction points. PS1 to PS4 are the four corners of the projected image corresponding to the correction points P1 to P4.

  FIG. 4 shows distortion correction processing by the projector 100 of the present embodiment. The processing in FIG. 4 is realized by the CPU 110 developing a program stored in the ROM 111 in the work area of the RAM 112 and controlling each operation block.

  In FIG. 4, the CPU 110 first instructs the user to start distortion correction processing (four-corner specification type distortion correction) by moving correction points at four corners in the image via the operation unit 113 or the remote controller. Is determined (S401). If the CPU 110 determines that a four-corner designated distortion correction start instruction has been received from the user, the process proceeds to S402.

  Next, the CPU 110 determines whether or not an instruction for selecting a point to be moved among the correction points at the four corners has been received from the user via the operation unit 113 or the remote controller (S402). If the CPU 110 determines that an instruction to select a point to be moved has been received, the process proceeds to S403. At this time, the CPU 110 may superimpose the OSD in the vicinity of the correction point on the OSD superimposing unit 320 in order to easily present the correction point selected as the movement target to the user. For example, the display content may be any information as long as the correction point being selected can be specified, such as changing the color near PS1 to a conspicuous color or blinking.

  On the other hand, if it is determined in S402 that the CPU 110 has not received the instruction, the process proceeds to S411.

  In S403, the CPU 110 waits for a user's correction point movement instruction. The correction point movement instruction is, for example, a signal when a correction point is set by pressing the direction key (up, down, left, right) of the operation unit 113 or the remote controller. When the CPU 110 determines that the correction point movement instruction has been received, the process proceeds to S404. On the other hand, if the CPU 110 determines that the instruction has not been received, the process proceeds to S411.

  In S404, when the CPU 110 determines that the user has pressed the direction key, the CPU 110 calculates the coordinates on the liquid crystal panel of the correction point after the movement (after the setting is completed) according to the pressed direction key (S404). For example, when the coordinate on the liquid crystal panel before the correction point P4 being selected is (x4, y4) and the right key is pressed, the coordinate after the movement is (x4 + m, y4). Here, m is a predetermined movement amount. However, assuming that the resolution of the liquid crystal panel is (xp, yp), when x4 + m <0 or xp ≦ x4 + m, it is determined that the liquid crystal panel is outside the projection region (outside the projection range) and is not moved.

  Next, the CPU 110 determines whether or not an instruction to end the movement of the correction point being selected has been received from the user via the operation unit 113 or the remote controller (S405). The correction point movement end instruction may be determined to be the end of setting when a predetermined key such as a determination key or a cancel key of the operation unit 113 or the remote controller is pressed, for example. If the CPU 110 determines that an instruction to end the movement of the selected correction point has been received, the process proceeds to S406. On the other hand, if the CPU 110 determines that the instruction has not been received, the process returns to S403.

  In S406, the CPU 110 instructs the deformation processing unit 330 to deform the input image into an image having correction points P1 to P4 as vertices. At this time, the CPU 110 obtains a projective transformation matrix M for image deformation and transmits it to the deformation processing unit 330. The deformation processing unit 330 deforms the input image according to the information received from the CPU 110.

  Next, the CPU 110 determines whether or not an instruction to end the four-corner designated distortion correction is received from the user via the operation unit 113 or the remote controller (S407). If the CPU 110 determines that a correction point movement end instruction has been received, the process advances to step S408. On the other hand, if the CPU 110 determines that the instruction has not been received, the process returns to S402.

  In S408, the CPU 110 determines whether the coordinates of the correction points P1 to P4 on the liquid crystal panel are in contact with the end of the projection area of the liquid crystal panel (whether they are inside the projection range). When the CPU 110 determines that at least one of the correction points P1 to P4 is in contact with the end of the projection area of the liquid crystal panel, the process is terminated. On the other hand, if the CPU 110 determines that all of the correction points P1 to P4 are not in contact with the end of the projection area of the liquid crystal panel, the process proceeds to S409.

  In step S409, the CPU 110 instructs the optical system control unit 170 to drive the zoom lens to optically reduce the projection image. The optical system controller 170 drives the zoom lens according to the instruction from the CPU 110 (S409).

  In S410, the CPU 110 corrects the correction points P1 to P4 such that the positions PS1 to PS4 on the projection plane of the correction points P1 to P4 determined in S407 are the same even after the zoom is changed in S409. The coordinates on the liquid crystal panel are recalculated (details will be described later).

  In S411, the CPU 110 instructs the deformation processing unit 330 to deform the input image into an image having the vertices at the correction points P1 to P4 determined in S410. At this time, the CPU 110 obtains a projective transformation matrix M for image deformation and transmits it to the deformation processing unit 330. The deformation processing unit 330 deforms the input image according to the information received from the CPU 110. When the deformation processing unit 330 finishes the deformation, the process returns to S408.

  <Description of Change in Projected Image During Distortion Correction Processing> Next, referring to FIG. 6, the change in the projected image during distortion correction processing will be described with respect to user operations and changes in the projected image on the projection plane. This will be explained in association with each other.

  Here, an example will be described in which the projected image 520 does not include the entire target shape 530 as shown in FIG. 6A before the distortion correction processing is started.

  First, in S402, it is assumed that the user has selected the correction point P4. Then, the direction of the correction point PS4 is moved by pressing the direction key of the remote controller until the position of PS4 overlaps the vertex of the target shape 530. At this time, in projector 100, S403 to S405 are repeated. When the user presses the determination button on the remote controller, the projected image is as shown in FIG.

  Next, the user sequentially selects correction points P3, P2, and P1 in the same procedure, and gives a movement instruction so that each correction point coincides with the vertex of the target shape 530. When the movement of all the correction points is completed, the projected image becomes as shown in FIG. 6C, and the projected image becomes equal to the target shape 530.

  At this time, the CPU 110 determines whether or not the correction points P1 to P4 on the liquid crystal panel are in contact with the end of the projection area of the liquid crystal panel in the projection state of FIG. This is to determine whether or not the four corners of the projection image after distortion correction (520 in FIG. 6C) are in contact with the outer periphery of the projection image before distortion correction (520 in FIG. 6A). be equivalent to.

  In this example, since the correction points P1 to P4 on the liquid crystal panel are not in contact with the end of the projection area of the liquid crystal panel, the projected image is zoomed out in S409. However, in the projection state as shown in FIG. 6C, if the image is simply reduced by zooming, the projection image 520 deviates from the target shape 530 as shown in FIG. 6D. Therefore, the CPU 110 corrects the coordinates of correction points P1 to P4 described below on the liquid crystal panel in order to bring the projected image 520 into the state of FIG. 6E that matches the target shape 530 before being reduced by zooming. Process.

  <Coordinate Correction Process for Correction Point> The coordinate correction process for the correction point will be described below with reference to FIG.

  FIG. 7 is a view of the relationship between the projector 100 and the projection plane 700 as viewed from directly above the projector 100, and the projection image shows only the upper side for convenience.

  First, as shown in FIG. 7A, the end points of the projected image before distortion correction are PS1 'and PS2'. In addition, the left and right projection angles of the projector 100 at this time are θR and θL.

  Here, it is assumed that the distortion correction is performed and the correction points PS1 and PS2 on the projection surface of the projection image are moved to the position coincident with the vertex of the target shape 530 as shown in FIG. The positional relationship between the points P1 and P2 on the liquid crystal panel at this time is the same as that on the virtual projection plane 710 facing the projector 100, and the projection relationship is as shown in FIG. The left and right projection angles after distortion correction are φL and φR as shown in FIG. This is obtained geometrically from the coordinates of the correction points P1 and P2 on the liquid crystal panel and θL and θR.

  Here, it is assumed that the projector 100 performs a zoom operation. The zoom operation is a change in the projection angles θL and θR. FIG. 7B shows a state where the zoom operation is performed and the projected image is reduced from FIG. 7A, and at this time, θ′L <θL and θ′R <θR.

  The fact that the positions PS1 and PS2 of the four corners of the correction point on the screen before and after the zoom operation are the same means that φL and φR do not change in FIGS. 7 (a) and 7 (b). For this purpose, it is necessary to correct the coordinates of the correction points P1 to P4 on the liquid crystal panel after the zoom operation. For example, the X coordinate after correction of P1 is obtained geometrically as follows.

First, the width W of the virtual panel is set such that the distance between the projector 100 and the virtual projection plane 710 is D.
W = D · tan (θ′L) + D · tan (θ′R)
It is.

Here, the distance (coordinate on the virtual panel) DP1 from the left end on the virtual panel to P1 is:
DP1 = D · tan (θ′L) −D · tan (φ′L)
It becomes.

If the resolution of the liquid crystal panel is PX, the X coordinate Xd1 of P1 on the liquid crystal panel is
Xd1 = (DP1 × PX) / W
Is required.

  Although the correction method of the X coordinate of P1 has been described above, the Y coordinate of P1 and the X and Y coordinates of P2 to P4 can also be obtained by the same procedure.

  As described above, after correcting the coordinates so that the center of the projection area approaches the center of the projection image of the correction points P1 to P4, the zoom operation is performed.

  As described above, according to the projector of the present embodiment, when the user determines the positions of the correction points at the four corners during distortion correction, the zoom operation is performed and the projection image maintains the relationship including the target projection position. The projection image is reduced as much as possible, and the projection image is subjected to distortion correction according to the reduction ratio. Therefore, it is possible to correct the distortion of the projection image to an appropriate size and shape without using an imaging unit, regardless of the positional relationship between the projection image before distortion correction and the projection area.

  [Embodiment 2] The projector of this embodiment has a configuration in which lens shift is also interlocked. Note that the overall configuration, basic operation, and configuration of the image processing unit of the projector according to the present embodiment are the same as those of the first embodiment, and thus description thereof is omitted.

  FIG. 9 shows the operation of the projector 100 of the present embodiment. The operation shown in FIG. 9 is realized by the CPU 110 developing a program stored in the ROM 111 in the work area of the RAM 112 and controlling each operation block. The processing in S901 to S908 in FIG. 7 is the same as S401 to S408 in FIG.

  In FIG. 9, if the CPU 110 determines in S908 that the correction points P1 to P4 are not in contact with the projection area end of the liquid crystal panel, the process proceeds to S909.

  In step S909, the CPU 110 determines whether the optical system control unit 170 drives the zoom lens to perform a zoom operation, or drives the shift lens to perform lens shift. In this determination, for example, it is determined that the lens shift is performed until θL and θR in FIG. 7 satisfy a condition of S910 described later, and the zoom is performed otherwise.

  If the CPU 110 determines to perform zooming, the process proceeds to S911. If the CPU 110 determines to perform lens shift, the process proceeds to S910.

  In S910, the CPU 110 instructs the optical system control unit 170 to perform lens shift. In response to an instruction from the CPU 110, the optical system control unit 170 drives the shift lens to move the position of the projection image on the projection plane. When the operation of S909 or S910 ends, the process proceeds to S912.

Note that the movement direction of the projected image by lens shift is compared to the case of performing S911 and S912 in the current projection state when zoom reduction and recalculation of the coordinates of the correction point are performed in S911 and S912. In this direction, the zoom can be changed in the reduction direction.
If it demonstrates using the symbol of Drawing 7 (a),
θL: θR = φp1: φp2
If θL and θR are changed so that the zoom ratio is reduced, correction points P1 and P2 are both positioned at the left and right projection area ends of the liquid crystal panel when zooming is reduced. However, it is better to consider P3, P4 (not shown) and the Y coordinate of each correction point. Similarly, the values of θL and θR are obtained, for example, and the average value may be set as the target value of the lens shift. When the lens shift is completed in S910, the CPU 110 corrects the coordinates on the liquid crystal panel P1 to P4. Similar to the correction at the time of the zoom operation described in the first embodiment, it is only necessary to obtain a condition in which φL and φR do not change when the projection angles θL and θR change.

  The processing of S911 to S913 is the same as the processing of S409 to S411 in FIG.

  <Description of Change in Projected Image During Distortion Correction Processing> Next, with reference to FIG. 10, the change in the projected image during distortion correction processing is described with respect to user operations and changes in the projected image on the projection plane. This will be explained in association with each other. Here, an example will be described in which the projected image 520 includes the entire target shape 530 as shown in FIG. 10A before the start of the distortion correction processing.

  First, the user sequentially selects correction points P1 to P4 in the same procedure as in the first embodiment, and gives a movement instruction so that the correction points coincide with the vertices of the target shape. When the movement of all the correction points is completed, the projected image becomes as shown in FIG. 10B, and the projected image becomes equal to the target shape 530.

  At this time, the CPU 110 determines whether or not the correction points P1 to P4 on the liquid crystal panel are in contact with the end of the effective projection area of the liquid crystal panel in the projection state of FIG. In this example, since the correction points P1 to P4 on the liquid crystal panel are not in contact with the effective projection region end of the liquid crystal panel, the optical system control unit 170 drives the shift lens in S409, and the projected image is displayed on the projection surface. The coordinates of the correction points P1 to P4 on the liquid crystal panel are corrected by the above-described procedure, and the projection state as shown in FIG.

  Thereafter, the zooming and the correction of the coordinate positions of the correction points P1 to P4 on the liquid crystal panel are performed in the same procedure as in the first embodiment, and the projection state is as shown in FIG.

  Through the above procedure, distortion correction can be performed so that the projected image 520 matches the target shape 530. Note that, in the procedure in which the lens shift is not performed as in the first embodiment, the projected image is as shown in FIG. On the other hand, the projected image on which the projector 100 of the present embodiment has corrected the distortion is as shown in FIG. 10E, and compared with the first embodiment, resolution degradation due to the distortion correction can be suppressed.

[Other Embodiments]
The present invention is also realized by executing the following processing. That is, software (program) that realizes the functions of this embodiment is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads out and executes the program. It is processing to do.

Claims (7)

Projection means for projecting an image onto a projection plane;
Setting means for moving the positions of a plurality of correction points in the image projected on the projection surface in response to a user operation;
Deformation means for deforming the shape of the projected image in accordance with the position of the correction point set by the setting means ;
Correction means for optically correcting the projection range by the projection means by zooming;
If positions corresponding to the plurality of correction points in the projected image after deformation by the deforming means is inside the projection range, and control means for controlling the correction means so that to reduce the projection range, A projection apparatus comprising: The control unit controls the correction unit to reduce the projection range so that a position corresponding to any one of the plurality of correction points set by the setting unit does not fall outside the projection range. The projection apparatus according to claim 1, wherein: The correction unit includes a lens shift unit that moves the projection range by driving a shift lens;
Wherein, after the center of the projection range in the center of the set of the plurality of correction points it is moved so as to approach by the setting unit, according to claim 1 or 2, characterized in that to reduce the projection range The projection apparatus described in 1. The control unit stops correction for reducing the projection range when a position corresponding to any one of the plurality of correction points set by the setting unit is in contact with an end of the projection range. The projection apparatus according to claim 1. A projection apparatus control method comprising: a projection unit that projects an image onto a projection plane; and a correction unit that optically corrects a projection range of the projection unit by zooming ,
A setting step of moving the positions of a plurality of correction points in the image projected on the projection surface in accordance with a user operation;
A deformation step of deforming the shape of the projected image according to the set position of the correction point ;
If positions corresponding to the plurality of correction points in the projected image after the deformation is inside the projection range, to have a controlling process of controlling the correction means so that to reduce the projection range A control method characterized by the above. The program for functioning a computer as each means of the projection apparatus described in any one of Claim 1 to 4 . A computer-readable storage medium storing a program for causing a computer to function as each unit of the projection apparatus according to any one of claims 1 to 4 .

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