JP5915001B2 - Projector and projector control method - Google Patents

Description

  The present invention relates to a projector and a projector control method.

  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, a projector having a keystone correction function for correcting trapezoidal distortion is known.

  Patent Document 1 discloses a keystone that calculates a relative angle between a screen and a projector, detects a frame border of a captured image based on the angle, and corrects trapezoidal distortion of the image based on the detection result of the border. A projection display device (projector) having a correction function is disclosed.

JP 2010-50542 A

  When such a keystone correction process is performed, the light emitted from the light source is not transmitted through the pixel area of the light modulation device such as a liquid crystal panel except for the area where the image subjected to the keystone correction is displayed. Thus, an all black image is formed. For this reason, the light of the part of the all black image is not utilized, but there existed a problem that the utilization factor of light fell. In addition, since the area where the keystone-corrected image is displayed is reduced with respect to all the pixel areas of the light modulation device, there is a problem that the projected image is also reduced.

  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 includes a light source and a light modulation device that has a pixel region including a plurality of pixels and modulates light emitted from the light source to the pixel region based on image data. A projection optical system that projects light modulated by the light modulation device, and corrected image data that is enlarged so as to protrude from the pixel area and in which distortion of the projected image is corrected, based on the image data. A correction image generation unit that generates the light, and the light modulation device modulates light from the light source based on the correction image data.

  According to such a projector, the correction image generation unit generates correction image data that is enlarged so as to protrude from the pixel region and corrects distortion of the projected image based on the image data. Then, the light modulation device modulates light from the light source based on the corrected image data. Accordingly, it is possible to form corrected image data larger than the pixel area, and it is possible to use many pixel areas for projection. Therefore, since the light modulation device can effectively use the light emitted from the light source, it is possible to avoid a decrease in the light utilization rate. Further, it is possible to avoid the image from being reduced as in the conventional keystone correction.

  Application Example 2 In the projector according to the application example, the correction image data generated by the correction image generation unit circumscribes at least one of vertices of the pixel region.

  According to such a projector, the corrected image data circumscribes at least one of the vertices of the pixel area. Thereby, it can avoid that correction | amendment image data becomes excessive with respect to a pixel area.

  Application Example 3 In the projector according to the application example described above, an imaging unit that captures a range including a projected image and generates a captured image, and a relative relationship between the projection surface on which the image light is projected and the projector An angle calculation unit that calculates an angle, a vanishing point calculation unit that calculates a vertical vanishing point and a horizontal vanishing point in the coordinate system of the pixel region based on the angle, and a vertex of the pixel region from the vertical vanishing point Forming a quadrilateral surrounded by two straight lines connecting two adjacent vertices, and two straight lines connecting two horizontal vertices of the pixel area from the horizontal vanishing point And the correction image generation unit generates the correction image data based on the quadrilateral.

  According to such a projector, the angle calculation unit calculates a relative angle between the projection plane and the projector. The vanishing point calculation unit calculates a vertical vanishing point and a horizontal vanishing point in the coordinate system of the pixel area. The quadrilateral forming unit forms a quadrilateral using the vertical vanishing point, the horizontal vanishing point, and the vertex of the pixel area. The corrected image generation unit generates corrected image data based on the quadrilateral. Thereby, it can avoid that correction | amendment image data becomes excessive with respect to a pixel area.

  Application Example 4 In the projector according to the application example described above, the projector further includes an illuminance measurement device that measures the illuminance of the projection surface, and the correction image generation unit has the illuminance measured by the illuminance measurement device at a predetermined illuminance. As described above, the corrected image data in which the size of the quadrilateral is changed is generated.

  According to such a projector, it is possible to avoid that the corrected image data becomes excessive with respect to the pixel region.

  Application Example 5 A projector control method according to this application example includes a light source and a pixel region including a plurality of pixels, and modulates light emitted from the light source to the pixel region based on image data. A projector control method comprising: a light modulation device; and a projection optical system that projects light modulated by the light modulation device, wherein the projection image is enlarged so as to protrude from the pixel region and distortion of a projected image A corrected image generating step for generating corrected image data corrected based on the image data; a corrected image modulating step for causing the light modulator to modulate light from the light source based on the corrected image data; It is characterized by providing.

  According to such a projector control method, corrected image data larger than the pixel area can be formed, and a large number of pixel areas can be used for projection. Therefore, since the light modulation device can effectively use the light emitted from the light source, it is possible to avoid a decrease in the light utilization rate. Further, it is possible to avoid the image from being reduced as in the conventional keystone correction.

  Further, when the projector and the control method thereof are constructed using a computer provided in the projector, the form and the application example described above are a program for realizing the function, or the program is stored in the computer. It is also possible to constitute in the form of a recording medium or the like recorded so as to be readable by the user. Recording media include flexible disks, hard disks, CD-ROM (Compact Disk Read Only Memory), DVD (Digital Versatile Disk), Blu-ray Disc (registered trademark), magneto-optical disk, nonvolatile memory card, internal storage of projector Use various computer-readable media such as devices (semiconductor memories such as RAM (Random Access Memory) and ROM (Read Only Memory)) and external storage devices (USB (Universal Serial Bus) memory, etc.). Can do.

1 is a block diagram showing a schematic configuration of a projector according to an embodiment. The flowchart of the expansion keystone correction process of a projector. It is explanatory drawing showing a pixel area | region and a quadrilateral area | region, (a) is a figure explaining a vanishing point, a pixel area | region, and a quadrilateral area | region, (b) demonstrates the projective transformation from a pixel area | region to a quadrilateral area | region. FIG. It is explanatory drawing of the projection image on a projection surface, (a) is explanatory drawing of the projection image before implementing enlarged keystone correction, (b) is the description of the projected image after implementing enlarged keystone correction. Figure.

  Hereinafter, embodiments will be described.

(Embodiment)
In the present embodiment, a projector that includes an imaging device and has an enlarged keystone correction function that corrects distortion of an inner display image while maintaining the outer shape of the projected image will be described.

  FIG. 1 is a block diagram illustrating a schematic configuration of a projector according to the present embodiment. The internal configuration of the projector 100 will be described with reference to FIG. The projector 100 projects image light representing an image and displays an image (hereinafter referred to as “projected image”) on a projection surface such as a screen SC.

  The projector 100 includes an A / D conversion unit 110, an internal memory 120, a light modulation device 130 such as a liquid crystal panel, a light modulation device driving unit 132, an illumination optical system 140 having a light source 140a, a projection optical system 150 as a projection lens, and a CPU 160. , An operation receiving unit 170, an imaging unit 180, and the like. Here, the internal memory 120, the light modulation device driving unit 132, the CPU 160, and the operation receiving unit 170 are connected to each other via the bus 102.

  The A / D conversion unit 110 includes various image input terminals for connecting to an external image supply device (not shown) such as a personal computer, a video playback device, a memory card, a USB storage, and a digital camera via a cable. The image signal is input from the image supply device. The A / D conversion unit 110 performs A / D conversion as necessary and outputs a digital image signal. Note that the image signal may be supplied wirelessly. The image signal may be supplied as a digital image signal.

  The internal memory 120 stores a computer program that functions as the image processing unit 122. The image processing unit 122 adjusts an image display state (for example, luminance, contrast, synchronization, tracking, color density, hue, etc.) with respect to the digital image signal output from the A / D conversion unit 110. And output to the light modulator driving unit 132. Further, the image processing unit 122 includes an angle calculation unit 122a, a vanishing point calculation unit 122b, a quadrangle formation unit 122d, a corrected image generation unit 122e, and the like as modules. The functions of these units will be described in detail in the explanation of the enlarged keystone correction process described later.

  The light modulation device driving unit 132 drives the light modulation device 130 that is a light modulation device based on the digital image signal input through the image processing unit 122. The light modulation device 130 forms an image for modulating the illumination light emitted from the illumination optical system 140 into image light in a pixel region on the surface (panel surface) of the light modulation device 130. In the present embodiment, it is assumed that the pixel area matches the light modulation device 130.

  The projection optical system 150 is attached to the front surface of the housing of the projector 100 and enlarges and projects the light modulated by the light modulation device 130 into image light.

  The operation reception unit 170 includes a plurality of keys and the like for issuing various instructions to the projector 100. As keys provided in the operation receiving unit 170, a “power key” for turning on / off the power, an “input switching key” for switching an input image signal, and a menu screen for performing various settings are displayed. "Menu key" to switch between / hide, "cursor key" used to move the cursor on the menu screen, "decision key" to determine various settings, "enlarged keystone correction to perform enlarged keystone correction on images" Key ", and" enlarged keystone step adjustment key "for performing enlarged keystone correction step by step. When the user operates the operation reception unit 170, the operation reception unit 170 outputs control information corresponding to the user's operation content to the CPU 160 via the bus 102.

  The operation receiving unit 170 may include a remote control signal receiving unit (not shown) and a remote controller (not shown) capable of remote operation. In this case, the remote controller emits an operation signal such as an infrared ray corresponding to the operation content of the user, and the remote control signal receiving unit receives this and transmits it to the CPU 160 as control information.

  The CPU 160 reads out and executes a computer program as the image processing unit 122 from the internal memory 120, thereby projecting an image on the screen SC and performing image processing such as enlargement keystone correction processing described later. In addition, the CPU 160 performs overall control of the operation of each unit in the projector 100.

  The imaging unit 180 includes a CCD camera and generates a captured image. The captured image generated by the imaging unit 180 is used for image processing in the image processing unit 122 of the internal memory 120. Note that the imaging unit 180 may include another imaging device instead of the CCD camera.

Next, an enlarged keystone correction process in which the projector 100 corrects distortion of the inner display while maintaining the outer shape of the projected image will be described.
FIG. 2 is a flowchart of the enlarged keystone correction process of the projector 100. The CPU 160 performs an enlarged keystone correction process according to program modules such as an angle calculation unit 122a, a vanishing point calculation unit 122b, a quadrilateral formation unit 122d, and a corrected image generation unit 122e provided in the image processing unit 122. The “enlarged keystone correction process” in the present embodiment is common to the conventional keystone correction process in that the distortion of the image on the projection plane is corrected. On the other hand, in the enlarged keystone correction process, the area where the all black image was displayed in the conventional keystone correction process is also used for displaying the image, and a part of the image that should be originally displayed is allowed to be lost. Is different from the conventional keystone correction processing.

  When the enlarged keystone correction key provided in the operation accepting unit 170 is pressed, the CPU 160 causes the light modulation device 130 to project a predetermined pattern image, and the imaging unit 180 captures the projected image (step S101). CPU 160 analyzes the captured image obtained by imaging unit 180 and calculates the relative angle between screen SC and projector 100 (step S102). The program module that performs this process corresponds to the angle calculation unit 122a.

  CPU 160 calculates a vertical vanishing point and a horizontal vanishing point in the coordinate system of light modulator 130 (step S103). The program module that performs this process corresponds to the vanishing point calculation unit 122b. Note that a known method is used for the calculation processing of the relative angle and the calculation processing of the vertical vanishing point and the horizontal vanishing point (see, for example, JP 2010-50542 A). Here, the straight lines passing through the vertical vanishing point in the coordinate system of the light modulation device 130 are parallel to each other on the projection surface such as the screen SC. Similarly, straight lines passing through the horizontal vanishing point in the coordinate system of the light modulation device 130 are parallel to each other on the projection plane. The straight line passing through the vertical vanishing point in the coordinate system of the light modulation device 130 and the straight line passing through the horizontal vanishing point in the coordinate system of the light modulation device 130 are orthogonal to each other on the projection plane.

  From the vertical vanishing point, the two straight lines connecting two vertices close to the vertical vanishing point among the vertices in the pixel region of the light modulation device 130 and the horizontal vanishing point from the vertical vanishing point in the pixel region of the light modulation device 130. Two straight lines connecting two vertices close to the horizontal vanishing point are formed. Then, a quadrilateral surrounded by these four straight lines is formed (step S104). The program module that performs this processing corresponds to the quadrilateral formation unit 122d.

  The CPU 160 performs projective transformation (described later) on the image of the pixel area of the light modulation device 130 into a quadrilateral area (step S105). The program module that performs the projective conversion process corresponds to the corrected image generation unit 122e, and the image data after the projective conversion process is the corrected image data. Then, the CPU 160 causes the light modulation device driving unit 132 to output pixel data of a region corresponding to the pixel region of the light modulation device 130 in the quadrilateral region image (corrected image data) subjected to the projective transformation (step S106). ). Then, the enlarged keystone correction process is terminated.

Here, the projective transformation from the pixel area of the light modulation device 130 to the quadrilateral area will be described.
FIG. 3 is an explanatory diagram showing a pixel area and a quadrilateral area, FIG. 3 (a) is a diagram for explaining a vanishing point, a pixel area, and a quadrilateral area, and FIG. 3 (b) is a pixel area. It is explanatory drawing explaining the projective transformation to a quadrilateral area | region.

  3A shows a pixel region PFL, a vertical vanishing point DPv, and a horizontal vanishing point DPh in the coordinate system (Xp axis, Yp axis) of the light modulation device 130. FIG. The pixel region PFL is rectangular and has four vertices a1, a2, a3, and a4. Then, a straight line L1 and a straight line L2 that connect two close vertices a1 and a2 of the vertices in the pixel area PFL from the vertical vanishing point DPv, and two close vertices a2 of the vertices in the pixel area PFL from the horizontal vanishing point DPh. , A3, a straight line L3 and a straight line L4 are represented. A quadrilateral region QU surrounded by the straight line L1, the straight line L2, the straight line L3, and the straight line L4 is formed. The quadrilateral region QU is shown with hatching. Here, it is assumed that the four vertices of the quadrangular region QU are v1, v2, v3, and v4.

  Here, since the straight lines passing through the vertical vanishing point in the coordinate system of the light modulation device 130 are parallel to each other on the projection plane such as the screen SC, the straight lines on the projection plane corresponding to the straight lines L1 and L2 are the projection planes. They are parallel to each other above. Similarly, the straight lines passing through the horizontal vanishing point in the coordinate system of the light modulation device 130 are parallel to each other on the projection plane, so the straight lines on the projection plane corresponding to the straight lines L3 and L4 are parallel to each other on the projection plane. It becomes.

In addition, since the straight line passing through the vertical vanishing point in the coordinate system of the light modulation device 130 and the straight line passing through the horizontal vanishing point in the coordinate system of the light modulation device 130 are orthogonal to each other on the projection plane, the straight line corresponding to the straight line L1. Is orthogonal to the straight lines corresponding to the straight lines L3 and L4 on the projection plane. Similarly, the straight line corresponding to the straight line L2 is orthogonal to the straight lines corresponding to the straight line L3 and the straight line L4 on the projection plane.
That is, since the area on the projection plane corresponding to the quadrangular area QU is a quadrilateral whose four vertices are at right angles, the image displayed in the pixel area PFL in the coordinate system of the light modulation device 130 is the quadrilateral area QU. By converting the image so that it is displayed, the distortion of the image can be corrected.

  FIG. 3B shows the correspondence between the pixel area PFL and the quadrangular area QU. In the enlarged keystone correction process, the pixel coordinates are converted so that the pixel area PFL is converted into a quadrilateral area QU (that is, converted as indicated by an arrow). More specifically, the coordinate transformation is performed so that the coordinates of the four vertices a1, a2, a3, and a4 of the pixel area PFL are transformed into the coordinates of the four vertices v1, v2, v3, and v4 of the quadrangular area QU. . This coordinate transformation is projective transformation in the present embodiment. Here, the coordinates of the vertices of the pixel area PFL are a1 = (X1, Y1), a2 = (X2, Y2), a3 = (X3, Y3), a4 = (X4, Y4), and the quadrilateral area QU The vertex coordinates are v1 = (x1, y1), v2 = (x2, y2), v3 = (x3, y3), and v4 = (x4, y4). That is, if the coordinates (X, Y) are converted to coordinates (x, y) by projective transformation, the coordinates (x, y) after projective transformation are expressed by the following equations (1) and (2). Is done.

  The coefficients A, B, C, D, E, F, G, and H in the equations (1) and (2) can be calculated using the following determinant (3) of projective transformation.

  Of the quadrangular region QU, only the portion included in the pixel region PFL can be actually displayed on the projection plane. That is, of the corrected image data of the quadrangular area QU obtained by projective transformation (coordinate transformation), a part corresponding to the pixel area PFL is finally displayed on the projection plane (screen SC).

Here, an image projected on the projection screen SC before and after the execution of the enlarged keystone correction process will be described.
FIG. 4 is an explanatory diagram of a projected image on the projection screen SC, FIG. 4 (a) is an explanatory diagram of a projected image before performing enlarged keystone correction, and FIG. 4 (b) is an enlarged key. It is explanatory drawing of the projection image after implementing stone correction.

  FIG. 4A shows a projected image PF1 when an image is projected with the projector 100 tilted with respect to the projection plane SC. In this state, since the enlarged keystone correction is not performed, the outer shape of the image is distorted in a trapezoidal shape, and the character “A” inside the image is also distorted. In such a state, if the above-described enlarged keystone correction process is performed, the outer shape of the image remains trapezoidal as shown in FIG. The distortion of “A” is corrected. In addition, since all the pixels of the pixel area PFL of the light modulation device 130 are projected on the projection image PF2, the portion LS (hatched portion) that protrudes from the pixel area PFL is not displayed on the projection image PF2. However, since the portion that is not displayed in this way is only a small part of the periphery of the image, it is considered that the influence on the user's viewing of the image is small.

According to the embodiment described above, the following effects can be obtained.
(1) The projector 100 forms a quadrangular region QU that has undergone projective transformation so as to include the pixel region PFL. Then, the light modulation device 130 modulates image light according to the pixel data of the pixel region PFL included in the quadrangular region QU. According to such enlarged keystone correction, the corrected image data of the quadrangular area QU larger than the pixel area PFL is formed, and all the pixel data of the pixel area PFL can be used for projection. Therefore, since the light modulation device 130 can use all the light emitted from the light source, it is possible to avoid a decrease in the light utilization rate. Further, with such an enlarged keystone correction, it is possible to avoid the image from being reduced as in the conventional keystone correction. That is, since it is possible to allow a user to view a large projected image, it is possible to give an impact to the user.

  (2) The projector 100 calculates a relative angle with the projection surface SC, and calculates a vertical vanishing point DPv and a horizontal vanishing point DPh. Then, the coordinate system of the vertical vanishing point DPv and the horizontal vanishing point DPh is converted into the coordinate system of the pixel region, and the quadrilateral region QUI is used by using the converted vertical vanishing point DPv, horizontal vanishing point DPh, and vertex of the pixel region PFL. Form. Then, corrected image data based on the quadrilateral region QU is generated. Thereby, it can be avoided that the quadrilateral area QU becomes excessive with respect to the pixel area PFL. That is, it is possible to reduce an image area that is lost in the projection image PF2.

  In addition, it is not limited to embodiment mentioned above, It is possible to implement by adding various change, improvement, etc. A modification will be described below.

  In the above embodiment, when the enlarged keystone correction key provided in the operation accepting unit 170 is pressed, the quadrangular region QU is uniquely formed using the vertex of the pixel region PFL. However, instead of uniquely calculating the quadrilateral area QU in this way, the user may perform enlarged keystone correction step by step. For example, the coefficients A, B, C, D, E, F, G, and H in Expression (1) and Expression (2) according to the number of times and time of pressing the enlarged keystone stage adjustment key provided in the operation reception unit 170 By changing, the enlargement ratio of the enlargement keystone correction can be changed.

  In the above embodiment, when the enlarged keystone correction key provided in the operation accepting unit 170 is pressed, the quadrangular area QU is calculated using the vertexes of the pixel area PFL, and the pixel area is set to be the quadrangular area QU. Projective transformation of PFL pixels is performed. Here, the calculation process of the quadrangular area QU is not limited as long as it is formed by a straight line passing through the vertical vanishing point DPv and the horizontal vanishing point DPh, and does not have to pass through the apex of the pixel area PFL.

  In the above embodiment, when the enlarged keystone correction key provided in the operation accepting unit 170 is pressed, the size of the quadrangular region QU is formed using the vertex of the pixel region PFL. Here, the size of the quadrangular region QU may be determined based on the illuminance of the projection screen. For example, the projector 100 further includes an illuminance measuring device (not shown) that measures the illuminance of the projection screen, and the size of the quadrangular region QU is changed so that the illuminance measured by the illuminance measuring device becomes a predetermined illuminance. By doing so, the enlargement ratio of the enlargement keystone correction can be changed.

  In the above embodiment, when the enlarged keystone correction key provided in the operation accepting unit 170 is pressed, the size of the quadrangular region QU is formed using the vertex of the pixel region PFL. Here, a predetermined pattern may be projected from the projection optical system 150, and the size of the quadrangular region QU may be determined based on the predetermined pattern imaged by the imaging unit 180.

  In the above embodiment, the image processing unit 122 is a computer program, but may be configured to include a circuit device (not shown) that performs image processing.

  In the enlarged keystone correction process of the above-described embodiment, the area where the all-black image is displayed in the conventional keystone correction process is also used for displaying the image, but the entire area may not be used for display. That is, there may be an all-black image in part.

  In the above embodiment, a transmissive liquid crystal panel is used as the light modulation device 130, but a reflective light modulation device such as a reflective liquid crystal panel can also be used. In addition, it is possible to use a micromirror array device that modulates light emitted from a light source by controlling the emission direction of incident light for each micromirror as a pixel.

  DESCRIPTION OF SYMBOLS 100 ... Projector, 102 ... Bus, 110 ... A / D conversion part, 120 ... Internal memory, 122 ... Image processing part, 122a ... Angle calculation part, 122b ... Vanishing point calculation part, 122d ... Quadrilateral formation part, 122e ... Correction Image generating unit 130... Light modulating device 132 132 Light modulating device driving unit 140. Illuminating optical system 150. Projecting optical system 160 CPU CPU 170 Operation receiving unit 180 Imaging unit

Claims (3)

A projector,
A light source;
A light modulation device having a pixel region composed of a plurality of pixels and modulating light emitted from the light source to the pixel region into image light based on image data;
A projection optical system that projects the image light modulated by the light modulation device;
A corrected image generation unit that generates the corrected image data that is enlarged so as to protrude from the pixel area and that corrects the distortion of the projected image, based on the image data;
An imaging unit that captures a range including the projected image and generates a captured image;
An angle calculation unit for calculating a relative angle between the projection surface on which the image light is projected and the projector;
A vanishing point calculating unit that calculates a vertical vanishing point and a horizontal vanishing point in the coordinate system of the pixel region based on the angle;
Two straight lines connecting two close vertices in the pixel area from the vertical vanishing point, and two straight lines connecting two close vertices in the pixel area from the horizontal vanishing point A quadrilateral forming part that forms an enclosed quadrilateral;
With
The corrected image generation unit generates the corrected image data based on the quadrilateral,
The light modulation device modulates light from the light source based on the corrected image data. The projector according to claim 1,
The corrected image data generated by the corrected image generation unit circumscribes at least one of the vertices of the pixel area. A light source having a pixel region composed of a plurality of pixels, a light modulation device that modulates light emitted from the light source into the pixel region into image light based on image data, and the light modulation device A projection optical system that projects the image light, and a projector control method comprising:
An imaging step of capturing a range including the projected image and generating a captured image;
An angle calculating step of calculating a relative angle between the projection surface on which the image light is projected and the projector;
A vanishing point calculating step for calculating a vertical vanishing point and a horizontal vanishing point in the coordinate system of the pixel region based on the angle;
Two straight lines connecting two close vertices in the pixel area from the vertical vanishing point, and two straight lines connecting two close vertices in the pixel area from the horizontal vanishing point A quadrilateral forming step to form an enclosed quadrilateral;
A corrected image generation step of generating corrected image data that is enlarged so as to protrude from the pixel region and in which distortion of a projected image is corrected, based on the image data and the quadrilateral;
A correction image modulation step of causing the light modulation device to modulate light from the light source based on the correction image data;
A projector control method comprising:

Images