JP2008277953A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector capable of suppressing a decrease in visibility due to trapezoidal distortion correction. <P>SOLUTION: A unidirectional correction unit thins out pixel values of image data input from an image signal processing unit to make correction such that an input image Gi is reduced more toward a tilt direction (+Y direction) as compared with the uncorrected image. Here, the unidirectional correction unit reduces the input image Gi only in a direction (±X direction) perpendicular to the tilt direction and does not hold the original aspect ratio of the input image Gi. Specifically, an image formation area 12i in a shape which is equal in height to a pixel area 12a of a liquid crystal light valve 12 and decreases in lateral width (dimension in a ±x direction) toward the tilt direction (+y direction) is set in the pixel area 12a. Then the image data have pixel values thinned out more at a position where the degree of enlargement by tilt projection is larger so as to form the input image Gi in the image formation area 12i. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a projector capable of correcting trapezoidal distortion associated with tilt projection.

  A trapezoid generated when an image is formed by a light modulation device in which a large number of pixels are formed in a matrix, and the image is projected onto a screen or the like, and is projected with tilting the projector with respect to the screen (tilted projection). A projector capable of correcting distortion is known (see, for example, Patent Documents 1 and 2). In such a projector, when forming an image with a light modulation device, it is possible to display an image in a regular shape (rectangle) by forming an image distorted so as to cancel the trapezoidal distortion. It has become.

  For example, when tilting projection is performed on an obliquely upper screen, the projected image extends upward and has a trapezoidal shape in which the upper base is longer than the lower base. For this reason, when forming an image with a light modulation device, an image to be displayed is formed by thinning out a larger number of pixels toward the upper side, reducing the vertical direction, and forming a trapezoidal image with a shorter upper base. It can be corrected to a regular shape (rectangle).

JP 2003-283963 A JP-A-9-261568

However, since the trapezoidal distortion correction as described above thins out pixels, that is, thins out pixel values that define the gradation of each pixel, part of the gradation information inherent in the image is lost. become. For this reason, when a comparatively small character etc. are contained in an image, it has the problem that the visibility will fall by the thinning-out of a pixel. In the projector described in Patent Document 2, the lack of gradation information is compensated by correcting the gradation information of neighboring pixels in accordance with the gradation information of pixels to be thinned out. As long as the image is expressed by pixels, there is a limit to the correction, and it has been impossible to avoid a decrease in visibility.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a projector capable of suppressing a decrease in visibility associated with keystone distortion correction.

  The projector according to the present invention performs tilt projection by using a light source, a light modulation device that modulates light emitted from the light source to form an image, a projection optical system that projects an image formed by the light modulation device, and the like. A trapezoidal distortion correction unit that reduces an image formed in the light modulation device in order to correct a trapezoidal distortion that occurs in some cases, and the trapezoidal distortion correction unit has the image perpendicular to the direction of the tilt. A one-way correction unit that reduces only in the direction is provided.

  According to this projector, since the one-way correction unit that reduces the image formed in the light modulation device only in the direction perpendicular to the tilt direction is provided, both the direction perpendicular to the tilt direction and the direction parallel to the tilt direction are provided. Compared with the case of reducing the image size to 1, it is possible to suppress a decrease in visibility due to the correction of the trapezoidal distortion.

  In this projector, the trapezoidal distortion correction unit includes a two-way correction unit that reduces the image in both a direction parallel to the tilt direction and a direction perpendicular to the tilt direction, and the one-direction correction unit. It is desirable to further include a distortion correction switching unit capable of switching between the correction by the correction and the correction by the two-direction correction unit.

  According to this projector, in addition to the one-direction correction unit, the trapezoidal distortion correction unit reduces the image in both the direction parallel to the tilt direction and the direction perpendicular to the tilt direction to correct the trapezoidal distortion. Since it has a correction unit and further includes a distortion correction switching unit that can switch between correction by a one-way correction unit and correction by a two-way correction unit, these two corrections can be set according to preference, image type, etc. It becomes possible to use properly according to.

  The projector further includes an image signal input unit to which an image signal representing an image to be projected is input, and a signal determination unit that determines the type of the image signal, and the distortion correction switching unit includes the signal determination unit. It is desirable to switch between the correction by the one-direction correction unit and the correction by the two-direction correction unit in accordance with the type of the image signal determined by.

  According to this projector, since the distortion correction switching unit switches between the correction by the one-direction correction unit and the correction by the two-direction correction unit according to the type of the input image signal, an appropriate value according to the type of the image signal is obtained. Correction can be performed.

  In the projector, when the signal determination unit determines that the type of the image signal is a signal input from a personal computer, it is preferable that the distortion correction switching unit switches to correction by the one-way correction unit.

  The image represented by the image signal input from the personal computer often includes character information. According to this projector, when the image signal is input from the personal computer, the distortion correction switching unit switches to the correction by the one-direction correction unit, so that it is easy to suppress the deterioration of the visibility of the character information. .

  Hereinafter, a projector according to an embodiment of the present invention will be described with reference to the drawings. The projector according to the present embodiment modulates light emitted from a light source, forms an image (input image) corresponding to an image signal input from an external image supply device, and projects the image onto a screen or the like. is there.

FIG. 1 is a block diagram illustrating a schematic configuration of a projector according to the present embodiment.
As shown in FIG. 1, the projector 1 includes an image projection unit 10 that projects an image, a control unit 20, an input operation unit 21, an image signal input unit 30, a mode determination unit 31, and an image signal processing unit. 32 and a trapezoidal distortion correction unit 33.

  The image projection unit 10 includes a light source 11 including a discharge-type light source lamp such as an ultra-high pressure mercury lamp and a metal halide lamp, and a liquid crystal light valve 12 as a light modulation device that modulates light emitted from the light source 11 to form an image. A projection lens 13 serving as a projection optical system for enlarging and projecting an image formed by the liquid crystal light valve 12 onto a screen SC and the like, and a light valve driving unit 14 for driving the liquid crystal light valve 12 are provided.

FIG. 2 is a front view showing the liquid crystal light valve 12.
As shown in FIG. 2, the liquid crystal light valve 12 includes 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 a driving voltage corresponding to an image signal is applied to each pixel 12p of the liquid crystal light valve 12 by driving the light valve driving unit 14, light emitted from the light source 11 is liquid crystal with different light transmittance for each pixel 12p. The light passes through the light valve 12 and becomes an image (image light) corresponding to the image signal, and is projected onto the screen SC or the like by the projection lens 13.

  Although not shown in the figure, the image projection unit 10 includes three liquid crystal light valves 12 for light of the three primary colors red (R), green (G), and blue (B). Yes. The light emitted from the light source 11 is separated into the three color lights by a light separation optical system (not shown), and then enters the liquid crystal light valve 12 for each color light. The image light of each color transmitted through the liquid crystal light valve 12 is synthesized for each pixel by a light synthesis optical system (such as a dichroic prism) (not shown), and is projected from the projection lens 13 as image light representing a color image.

  Returning to FIG. 1, the control unit 20 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) including a flash memory, a RAM (Random Access Memory) used for temporary storage of various data, etc. (Not shown) and function as a computer. The control unit 20 performs overall control of the operation of the projector 1 by the CPU operating according to a control program stored in the ROM.

  The input operation unit 21 includes a plurality of keys for giving various instructions to the projector 1. The keys provided in the input operation unit 21 include a power key for turning on / off the power, a menu key for switching display / non-display of a menu image for performing various settings, a source key for switching an input source, There is a keystone correction key for instructing correction of keystone distortion. When the user operates the input operation unit 21, the input operation unit 21 outputs an operation signal corresponding to the operation content of the user to the control unit 20. The input operation unit 21 may be configured using a remote control (not shown) capable of remote operation. In this case, the remote controller emits 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 image signal input unit 30 includes various connection terminals for connecting to an external image supply device 2 such as a PC (personal computer) or a video reproduction device via a cable. An image signal is input. Image signals can be broadly classified into PC signals such as analog RGB signals that are mainly input from a PC, and video signals that are input as a composite signal or component signal from a video playback device. Furthermore, these signals can be classified into a number of display modes according to differences in resolution, scanning frequency, and the like. In addition, the image signal includes a signal representing the gradation information of the image (hereinafter referred to as RGB signal) and various synchronizing signals (horizontal synchronizing signal H, vertical synchronizing signal V, etc.) that define the scanning timing of the signal. The image signal input unit 30 separates the RGB signal and the synchronization signal, and outputs the RGB signal to the image signal processing unit 32 and the synchronization signal to the mode determination unit 31.

  The mode determination unit 31 determines the display mode of the image signal based on the input synchronization signal and the like, and notifies the image signal processing unit 32 and the control unit 20 of the determination result.

Upon receiving the notification from the mode determination unit 31, the image signal processing unit 32 samples the image signal (RGB signal) at a timing suitable for the determined display mode, and generates digital image data corresponding to the image signal. To do. Further, the image signal processing unit 32 performs various data processing (image processing) on the generated image data, and outputs the processed image data to the trapezoidal distortion correction unit 33.
Note that the image data output from the image signal processing unit 32 is generated for each color light, and includes a plurality of pixel values corresponding to all the pixels 12p in the pixel region 12a of each liquid crystal light valve 12. The pixel value determines 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.

  The trapezoidal distortion correcting unit 33 is referred to as a tilt direction (tilted direction, hereinafter tilt direction) when tilting projection, that is, when projecting an image with the projector 1 tilted with respect to the screen SC. ) Is corrected (trapezoidal distortion correction) in order to suppress distortion (trapezoidal distortion). When the user operates the keystone correction key of the input operation unit 21, the control unit 20 instructs the keystone distortion correction unit 33 to perform the keystone distortion correction.

The trapezoidal distortion correction unit 33 thins out the pixel values from the image data, and reduces the input image to be formed by the liquid crystal light valve 12 toward the tilt direction (two-direction correction unit 33a, and A one-direction correction unit 33b) is provided, and correction is performed by any one of them. The two-direction correction unit 33a reduces the input image in both a direction perpendicular to the tilt direction and a direction parallel to the tilt direction, and the one-direction correction unit 33b is a direction perpendicular to the tilt direction. (The details will be described later). The trapezoidal distortion correction unit 33 outputs the corrected image data to the light valve driving unit 14. Note that, when the keystone distortion correction is not performed, the image data output from the image signal processing unit 32 is output to the light valve driving unit 14 as it is.
When the light valve driving unit 14 drives the liquid crystal light valve 12 according to input image data, that is, a pixel value for each pixel 12p, an input image corresponding to the image data is projected onto the screen SC.

Next, trapezoidal distortion correction by the trapezoidal distortion correction unit 33 will be described with reference to FIGS.
FIGS. 3A to 3E are explanatory diagrams for explaining trapezoidal distortion correction and are diagrams illustrating a state in which trapezoidal distortion correction is not performed. Here, (a) is a front view of the liquid crystal light valve 12, (b) is a side view showing how the projector 1 projects horizontally, and (c) is a projection displayed on the screen SC at that time. It is a front view which shows an image. Further, (d) is a side view showing a state in which the projector 1 performs the projection, and (e) is a front view showing a projected image displayed on the screen SC at that time.

3 to 5, the horizontal direction toward the liquid crystal light valve 12 is the ± x direction, the vertical direction is the ± y direction, the horizontal direction toward the screen SC is the ± X direction, and the vertical direction is the ± Y direction. To do. Here, the X direction and the Y direction of the screen SC correspond to the x direction and the y direction of the liquid crystal light valve 12, respectively. For example, the pixels on the upper right (+ x, + y side) of the pixel region 12a are transmitted. The light is projected on the upper right (+ X, + Y side) of the screen SC.
3 to 5, the lattice pattern shown in the pixel area 12a and the projected image Ga indicates the correspondence between the image formed in the pixel area 12a and the projected image Ga projected on the screen SC. Therefore, it is a supplementary line, and does not mean that such a pattern is actually displayed.

  As shown in FIG. 3A, when the trapezoidal distortion correction is not performed, the liquid crystal light valve 12 forms the input image Gi over the entire pixel region 12a. That is, in this case, the area for forming the input image Gi (image forming area 12i) coincides with the pixel area 12a. Here, as shown in FIGS. 3B and 3C, when the projector 1 is installed horizontally and performs projection with no tilt on the screen SC, the projected image Ga ( The input image Gi) has a rectangular shape having the same aspect ratio (aspect ratio) as that of the pixel region 12a. On the other hand, as shown in FIGS. 3D and 3E, when the projector 1 is installed tilted with respect to the screen SC and projected upward (in the + Y direction), it is displayed on the screen SC. The projected image Ga (input image Gi) is enlarged in the ± X direction and the + Y direction and distorted in a trapezoidal shape as it goes in the tilt direction (+ Y direction).

  4A and 4B are explanatory diagrams for explaining trapezoidal distortion correction by the two-way correction unit 33a, FIG. 4A is a front view of the liquid crystal light valve 12, and FIG. 4B is tilt projection. It is a front view which shows the projection image displayed on screen SC when performing.

  The two-direction correction unit 33a performs pixel value decimation from the image data input from the image signal processing unit 32, and reduces the input image Gi as it goes in the upward direction (+ Y direction), compared to the case where correction is not performed. Make the following corrections. Here, the two-direction correction unit 33a reduces the input image Gi in both the direction perpendicular to the tilt direction (± X direction) and the direction parallel to the tilt direction (± Y direction), thereby reducing the input image Gi. The original aspect ratio is maintained. Specifically, as shown in FIGS. 4A and 4B, the pixel region 12a of the liquid crystal light valve 12 has an opposite trapezoidal shape that can cancel the trapezoidal distortion, that is, a height lower than that of the pixel region 12a. Then, the image forming region 12i having a shape in which the lateral width (the dimension in the ± x direction) is reduced toward the tilt direction (+ y direction) is set. Next, in order to form the input image Gi in the image forming area 12i, the two-direction correction unit 33a thins out more pixel values from the image data at positions where the degree of enlargement by tilt projection is higher, and the image forming area 12i. The image data is corrected so that the light transmittance of each pixel 12p included in the region outside the region, that is, the region that does not contribute to the formation of the input image Gi (the surplus region 12n) is minimized. As a result, as shown in FIG. 4B, the distortion of the input image Gi due to tilt projection is corrected, and the region Gn in the projection image Ga corresponding to the surplus region 12n is hardly irradiated with light. The input image Gi is displayed on the screen SC in a regular shape (rectangular shape) that maintains the aspect ratio. As described above, the correction by the two-way correction unit 33a corrects the distortion of the image and maintains the aspect ratio, and thus is suitable for correcting an image represented by a video signal such as a movie.

  5A and 5B are explanatory diagrams for explaining trapezoidal distortion correction by the one-direction correction unit 33b, FIG. 5A is a front view of the liquid crystal light valve 12, and FIG. 5B is tilt projection. It is a front view which shows the projection image displayed on screen SC when performing.

  Similar to the two-direction correction unit 33a, the one-direction correction unit 33b performs pixel value decimation from the image data input from the image signal processing unit 32, and the input image Gi is in the vertical direction (when the correction is not performed). Correction is performed so that the image is reduced toward the + Y direction. However, the one-direction correction unit 33b reduces the input image Gi only in the direction perpendicular to the tilt direction (± X direction) and does not maintain the original aspect ratio of the input image Gi. Specifically, as shown in FIGS. 5A and 5B, the lateral expansion (± X direction) of the input image Gi associated with the tilt projection can be offset in the pixel region 12a of the liquid crystal light valve 12. An oppositely formed trapezoidal shape, that is, an image forming region 12i having the same height as the pixel region 12a and a shape in which the lateral width is reduced toward the tilt direction (+ y direction) is set. Next, in order to form the input image Gi in the image forming area 12i, the one-direction correction unit 33b thins out more pixel values from the image data at positions where the degree of enlargement by tilt projection is higher, and in the surplus area 12n. The image data is corrected so that the light transmittance of each pixel 12p included is minimized. As a result, as shown in FIG. 5B, the lateral expansion of the input image Gi due to tilt projection is corrected, and the region Gn in the projection image Ga corresponding to the surplus region 12n is almost irradiated with light. Therefore, the input image Gi is displayed on the screen SC in a rectangular shape although the aspect ratio is broken and becomes vertically long. As described above, in the correction by the one-direction correction unit 33b, the input image Gi is reduced only in the direction perpendicular to the tilt direction, and thus the aspect ratio is lost. An image can be formed with a larger number of pixels. Therefore, the correction by the one-way correction unit 33b is suitable for correcting an image that requires character visibility, such as an image represented by a PC signal.

Next, the operation of the projector 1 according to this embodiment will be described. The projector 1 corrects a trapezoidal distortion according to whether the input image signal is a video signal or a PC signal, that is, correction by the two-way correction unit 33a and correction by the one-way correction unit 33b. And are to be switched.
FIG. 6 is a flowchart for explaining the operation when the projector 1 performs the trapezoidal distortion correction. When the keystone key of the input operation unit 21 is operated by the user, the control unit 20 operates according to the flow shown in FIG.

  As shown in FIG. 6, in step S101, the control unit 20 acquires the display mode determined by the mode determination unit 31, and in step S102, depending on the acquired display mode, the image signal is a video signal or a PC signal. Determine if the signal. If the image signal is a video signal, the process proceeds to step S103. If the image signal is a PC signal, the process proceeds to step S104.

  When the image signal is a video signal and the process proceeds to step S103, the control unit 20 instructs the trapezoidal distortion correction unit 33 to perform the trapezoidal distortion correction by the two-way correction unit 33a and performs processing. Exit. Thereby, the trapezoidal distortion correction unit 33 performs trapezoidal distortion correction by the two-way correction unit 33a on the image signal (video signal) input thereafter.

  On the other hand, when the image signal is a PC signal and the process proceeds to step S104, the control unit 20 instructs the trapezoidal distortion correction unit 33 to perform the trapezoidal distortion correction by the unidirectional correction unit 33b. To finish the process. Thus, the trapezoidal distortion correction unit 33 performs trapezoidal distortion correction by the one-way correction unit 33b on the image signal (PC system signal) input thereafter.

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, the trapezoidal distortion correction unit 33 includes the one-direction correction unit 33b that reduces the image formed on the liquid crystal light valve 12 only in the direction perpendicular to the tilt direction. Compared with the case where the image is reduced both in the direction perpendicular to the tilt direction and in the direction parallel to the tilt direction, it is possible to suppress a decrease in visibility due to the correction of the trapezoidal distortion.

  (2) According to the projector 1 of the present embodiment, the trapezoidal distortion correction unit 33 reduces the image in both the direction perpendicular to the tilt direction and the direction parallel to the tilt direction in addition to the one-direction correction unit 33b. Since the control unit 20 switches between correction by the one-direction correction unit 33b and correction by the two-way correction unit 33a, the two-way correction unit 33a that corrects the trapezoidal distortion is used. It is possible to use properly according to the type of the.

  (3) According to the projector 1 of the present embodiment, the control unit 20 switches between the correction by the one-direction correction unit 33b and the correction by the two-direction correction unit 33a according to the type of the input image signal. Appropriate correction according to the type of signal can be performed. Here, when the image signal is a video system, if the aspect ratio of the input image Gi is lost, an unnatural impression is often given to the viewer. Therefore, the two-way correction unit 33a as in the present embodiment. It is desirable to correct by Further, when the image signal is a PC system, the image often includes a large amount of character information. Therefore, correction by the one-direction correction unit 33b is performed as in the present embodiment to suppress a decrease in visibility. Is desirable.

  In the present embodiment, the control unit 20 switches between correction by the one-direction correction unit 33b and correction by the two-direction correction unit 33a, and thus functions as a distortion correction switching unit of the present invention. Further, since the mode determination unit 31 and the control unit 20 determine the type (image system or PC system) of the image signal, they function as the signal determination unit of the present invention.

(Modification)
Moreover, you may change the embodiment of this invention as follows.
In the embodiment, the trapezoidal distortion correction method (correction by the one-direction correction unit 33b or correction by the two-direction correction unit 33a) is switched according to the type of the image signal (PC system or video system). The method switching is not limited to the method based on the type of image signal. For example, the input operation unit 21 may be provided with a key for switching the correction method, and may be switched according to a user operation.

  In the embodiment, when the keystone correction key is operated, the keystone distortion correction is performed by the two-direction correction unit 33a on the video image signal, and the one direction is applied to the PC image signal. Although the trapezoidal distortion correction is performed by the correction unit 33b, the combination of the image signal type and the correction method is not limited to this. Further, the correction method desired by the user (correction by the one-direction correction unit 33b or correction by the two-direction correction unit 33a) is stored in the storage means (ROM or RAM) in the control unit 20, for example, the image signal is In the case of a video system, correction can be performed according to the correction method stored in the storage means, and in the case where the image signal is a PC system, the correction by the one-way correction unit 33b can be performed unconditionally. is there.

  In the above-described embodiment, an example in which the projector 1 performs projection in the + Y direction has been described. However, the present invention is also applied to projection in other directions (−Y direction and ± X direction). Is possible.

  In the above 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 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.

  In the embodiment, the light source 11 is constituted by a discharge light source lamp, but a solid light source such as an LED (Light Emitting Diode) light source or other light sources may be used.

1 is a block diagram showing a schematic configuration of a projector according to an embodiment of the invention. The front view which shows a liquid crystal light valve. It is explanatory drawing which shows the state which has not performed the trapezoid distortion correction, (a) is a front view of a liquid crystal light valve, (b) is a side view which shows a mode that a projector projects horizontally, (c), A front view showing the projected image displayed on the screen at that time, (d) is a side view showing how the projector performs projection and (e) is a front view showing the projected image displayed on the screen at that time. Figure. It is explanatory drawing for demonstrating the trapezoid distortion correction by a two-direction correction | amendment part, (a) is a front view of a liquid crystal light valve, (b) shows the projection image displayed on a screen when tilting projection is performed. Front view. It is explanatory drawing for demonstrating the trapezoid distortion correction by a 1 direction correction | amendment part, (a) is a front view of a liquid crystal light valve, (b) shows the projection image displayed on a screen when tilting projection is performed. Front view. The flowchart explaining the operation | movement at the time of performing a trapezoid distortion correction.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Image supply apparatus, 10 ... Image projection part, 11 ... Light source, 12 ... Liquid crystal light valve, 12a ... Pixel area | region, 12i ... Image formation area, 12n ... Excess area | region, 12p ... Pixel, 13 ... Projection lens , 14: Light valve drive unit, 20: Control unit, 21: Input operation unit, 30 ... Image signal input unit, 31 ... Mode determination unit, 32 ... Image signal processing unit, 33 ... Trapezoid distortion correction unit, 33a ... Two directions Correction part, 33b ... One direction correction part, Ga ... Projection image, Gi ... Input image, SC ... Screen.

Claims (4)

A light source;
A light modulation device that modulates the light emitted from the light source to form an image;
A projection optical system for projecting an image formed by the light modulation device;
A trapezoidal distortion correction unit that reduces an image formed in the light modulation device in order to correct the trapezoidal distortion that occurs when tilt projection is performed;
Have
The projector is characterized in that the trapezoidal distortion correction unit includes a one-direction correction unit that reduces the image only in a direction perpendicular to the tilt direction. The projector according to claim 1,
The trapezoidal distortion correction unit includes a two-direction correction unit that reduces the image in both a direction parallel to the tilt direction and a direction perpendicular to the tilt direction,
A projector further comprising a distortion correction switching unit capable of switching between correction by the one-direction correction unit and correction by the two-direction correction unit. The projector according to claim 2,
An image signal input unit to which an image signal representing an image to be projected is input;
A signal determination unit for determining the type of the image signal;
Further comprising
The distortion correction switching unit switches between correction by the one-direction correction unit and correction by the two-direction correction unit according to the type of the image signal determined by the signal determination unit. The projector according to claim 3, wherein
The projector according to claim 1, wherein when the signal determination unit determines that the type of the image signal is a signal input from a personal computer, the distortion correction switching unit switches to correction by the one-way correction unit.

Images