JP5219651B2 - Display device - Google Patents

Description

  The present invention relates to a display device, for example, a display device that incorporates a drive circuit that drives a liquid crystal panel for displaying an image and projects an image generated by the liquid crystal panel onto a screen.

Conventionally, as this type of device, a projector that projects an image generated by a liquid crystal panel onto a screen is known. When a projector projects an image from an oblique direction with respect to the screen, the projection screen may be distorted, for example, in a trapezoidal shape. Therefore, some projectors have a keystone correction function that eliminates the trapezoidal distortion of the projection screen by adding correction that cancels the trapezoidal distortion to the projection image (for example, Patent Document 1).
JP 2000-122617 A

  In a conventional projector, when performing keystone correction, a projection image formed on a display element of a liquid crystal panel is enlarged or reduced in a horizontal direction or a vertical direction. In this way, the distortion of the trapezoidal shape of the projection screen and the distortion of the video area on the display element cancel each other, and the image is displayed on the screen so as to approach the rectangular video display area having a normal aspect ratio. This operation may be performed automatically or manually.

  However, when performing keystone correction, the portion where the image is reduced is reduced by thinning out part of the pixel data of the original projected image, so the resolution is reduced for the portion where the image is reduced. It will end up. When the resolution of the image is lowered, for example, it becomes difficult to see the edge portion (high-frequency component) of the image, and it is difficult to see fine characters. That is, there is a problem that the visibility of the edge portion and the character portion of the image is reduced at the portion where the image is reduced (compressed) by the keystone correction.

  This invention is made | formed in view of such a problem, and it aims at providing the display apparatus which can suppress the fall of visibility.

In order to solve such a problem, the projection apparatus of the present invention includes a reproduction unit that reads a file from a storage medium and reproduces it, and a projection unit that projects the reproduced image on a screen, and the projection unit The keystone correction means for deforming the shape of the image projected by the above, the determination means for determining the file type, and the deformation of the image shape by the keystone correction means according to the file type determined by the determination means have a control means for determining the degree of restriction of said determining means determines, when the information data is a file containing text, to determine the display position of the text, the control means, by said determining means The degree of restriction on the deformation of the image shape by the keystone correcting means is determined according to the displayed position of the text .

  According to the present invention, the keystone correction operation is limited when the projected image includes characters and high-frequency components, so that a reduction in visibility can be suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  In the present embodiment, a projector incorporating a liquid crystal panel will be described.

  FIG. 1 is a diagram showing the main configuration of the projector of this embodiment.

  Reference numeral 100 denotes a projector main body. Reference numeral 101 denotes a control unit for controlling each block of the projector. Reference numeral 102 denotes an operation unit that receives an operation from the user. Reference numeral 103 denotes a power supply unit that controls power supply to each block of the projector.

  A liquid crystal unit 104 includes one liquid crystal panel, three liquid crystal panels, and the like, and forms an image on the liquid crystal panel. Reference numeral 105 denotes a liquid crystal driving unit for forming an image on the liquid crystal panel of the liquid crystal unit 104 based on the input image signal. A light source 106 supplies light to the liquid crystal unit 104. A projection optical system 107 projects an optical image obtained by supplying light emitted from the light source 106 to the liquid crystal unit 104 on a screen (not shown). Reference numeral 108 denotes a light source control unit 108 for controlling the amount of light of the light source 106 and the like. Reference numeral 109 denotes an optical system control unit 109 that controls operations of a zoom lens, a focus lens, and the like of the projection optical system 107 and performs zoom magnification, focus adjustment, and the like.

  An analog input unit 110 receives an analog video signal from a PC, a DVD player, a TV tuner, or the like, and includes an RGB terminal, an S terminal, and the like. Reference numeral 111 denotes a DA converter that converts the video signal obtained by the analog input unit into a digital signal. A digital input unit 112 receives a digital video signal from a PC, a DVD player, or the like, and includes an HDMI terminal and the like. In the case of an HDMI terminal, a control signal may also be transmitted from the outside at the same time, and thereby video control or the like may be performed. A USB interface 113 receives a file of various information data such as video data, image data, and a video file from the outside, or writes the file to the outside. A pointing device, a keyboard, a USB flash memory, or the like may be connected. Reference numeral 114 denotes a card interface that reads and writes various information data files such as video data, image data, and video files on a card-type recording medium. An SD card, a compact flash (registered trademark), or the like can be inserted. ing. A communication unit 115 receives and transmits various information data files such as video data, image data, and video files from the intranet and the Internet, and other command signals. For example, the communication unit 115 may be a wired LAN or a wireless LAN. It is configured. Reference numeral 116 denotes a built-in memory for storing various information data files such as video data, image data, and video files, and includes a semiconductor memory or a hard disk.

  For example, a document file input from the card interface 114 is played back by the file playback unit 132. Then, the file reproduction unit generates an image signal for posting to the user from the document file, and outputs the image signal to the image processing unit 117.

  Further, the video signal and the image signal input by the digital input unit 112 are directly transmitted to the image processing unit 117.

  The image processing unit 117 performs a correction suitable for displaying on the liquid crystal unit 104 on the image signal obtained by the interface and the file reproduction unit 132, the video signal obtained by the control unit 101, and the like. For example, the number of pixels of the image signal is converted according to the number of pixels of the liquid crystal panel, and the number of frames of the input video signal is doubled for the AC drive of the liquid crystal panel, and correction suitable for image formation by the liquid crystal panel is performed. . By the way, the AC drive of the liquid crystal panel is a method of alternately switching the direction of the voltage applied to the liquid crystal of the liquid crystal panel, and the liquid crystal panel generates an image regardless of whether the direction of the voltage applied to the liquid crystal is the forward direction or the reverse direction. It uses properties that can be done. At this time, since it is necessary to send the image for the forward direction and the image for the reverse direction one by one to the liquid crystal drive unit 105, the image processing unit 117 performs a process of doubling the number of frames of the video signal. Do. The liquid crystal driving unit 105 forms an image on the liquid crystal panel of the liquid crystal unit 104 based on the image signal obtained by the image processing unit 117.

  In addition, when the image processing unit 117 projects an image from an oblique direction with respect to the screen and the projection screen is distorted into, for example, a trapezoid, the image processing unit 117 deforms the shape of the image so as to cancel the trapezoidal distortion with respect to the projection image. Also performs keystone correction. When performing the keystone correction, the enlargement / reduction ratio in the horizontal direction and / or the vertical direction of the image displayed on the liquid crystal panel is changed. In this way, the trapezoidal distortion of the projection screen and the distortion of the video area on the display element cancel each other, and the image is displayed on the screen so as to approach a rectangular video display area having a normal aspect ratio. This keystone correction may be automatically performed based on an inclination angle obtained by an inclination sensor 118 described later, or may be operated by a user operating the operation unit 102 or the like.

  Reference numeral 118 denotes an inclination sensor that detects the inclination of the projector 100. Reference numeral 119 denotes a timer that detects the operation time of the projector 100, the operation time of each block, and the like. A thermometer 120 measures the temperature of the light source 106 of the projector, the temperature of the liquid crystal unit 104, the outside air temperature, and the like.

  121 and 122 are infrared receiving units that receive infrared rays from a remote controller and other devices attached to the projector 100 and send signals to the control unit 101. For example, the infrared receiving units 121 and 122 are installed at a plurality of locations such as the front-rear direction of the projector. In the present embodiment, the infrared receiver 121 is disposed behind the projector body, and the infrared receiver 122 is disposed in front of the projector body.

  A focus detection unit 123 detects the focal length by detecting the distance between the projector 100 and a screen (not shown). Reference numeral 124 denotes an imaging unit that captures an image of a screen (not shown). Reference numeral 125 denotes a screen photometry unit that measures the amount and luminance of light reflected by the screen. Reference numeral 126 denotes a light source photometric unit that measures the amount and luminance of light emitted from the light source.

  Reference numeral 127 denotes a display unit that is disposed in the main body of the projector 100 and displays a projector status, a warning, and the like. Reference numeral 128 denotes a display control unit that controls the display unit 127.

  A battery 129 supplies power when the projector 100 main body is carried and used. A power input unit 130 receives AC power from the outside, rectifies the AC power to a predetermined voltage, and supplies the rectified voltage to the power source unit 103.

  Reference numeral 131 denotes a cooling unit for cooling the projector 100 by releasing the heat in the projector 100 to the outside. The cooling unit 131 includes, for example, a heat sink and a fan.

  Here, the normal operation of the projector 100 will be described.

  The control unit 101 of the projector according to the present embodiment instructs the power supply unit 103 to supply power to each block when the operation unit 102 is instructed to turn on the power, and puts each block in a standby state. After the power is turned on, the control unit 101 instructs the light source control unit 108 to start light emission from the light source 106. Next, the control unit 101 instructs the optical system control unit 109 to adjust the projection optical system 107 from the focus information obtained by the focus detection unit 123. The optical system control unit 109 operates the zoom lens and the focus lens of the projection optical system 107 to control the projection light to form an image on the screen screen.

  In this way, the projection is ready. Next, for example, the video signal input to the digital input unit 112 is converted to a resolution suitable for the liquid crystal unit 104 by the image processing unit 117, and gamma correction, luminance unevenness countermeasure correction, and keystone correction are added. The video signal corrected by the image processing unit 117 is formed as an image on the liquid crystal unit 104 by the liquid crystal driving unit 105.

  The image formed on the liquid crystal panel of the liquid crystal unit 104 is guided to the projection optical system 107 by the light emitted from the light source 106, and the projection optical system 107 projects the image on a screen (not shown).

  During projection, the control unit 101 detects the temperature of the light source 106 or the like with the thermometer 120, and when the temperature of the light source becomes 40 degrees or more, for example, operates the cooling unit 131 to cool it.

  Then, when an instruction to turn off the power is given by the operation unit 102, the control unit 101 communicates with each block so as to perform a termination process. When preparation for termination is completed, the power supply unit 103 sequentially ends power supply to each block. The cooling unit 131 operates for a while after the power is turned off to cool the projector.

  Although the case where the video signal input from the digital input unit 112 is displayed has been described here, the same processing is performed when the video data input from the various interfaces is displayed.

  Next, keystone correction will be described. In this embodiment, a case where manual keystone correction is performed will be described. In this embodiment, a case where the projector 100 projects upward about 10 degrees from the horizontal will be described.

  2, 3, and 4 are diagrams for explaining the keystone correction. The screen projection image and the source image output by the image processing unit 117 when the keystone correction is not performed are shown side by side. It is a figure. Reference numeral 201 denotes an image projected on the screen. Reference numeral 202 denotes a source image output by the image processing unit 117.

  For example, when the projector 100 projects upward from the horizontal, the distance between the optical system 107 and the screen is different between the upper end and the lower end of the projection surface. Therefore, the upper part of the image is stretched, and an image as shown in the projected image 201 is projected. At this time, the source image 202 outputs an image having a normal aspect ratio.

  Therefore, the user operates the operation unit 102 while checking the screen to perform keystone correction. That is, the image processing unit 117 changes the degree of keystone correction for the projected image in accordance with the keystone correction value set by the operation unit 102. For example, in this embodiment, the keystone correction process is performed so that the upper end becomes shorter than the lower end of the screen as the correction value is increased. Specifically, if the keystone value is +5, the image processing unit 117 transforms the image of the source image 302 into a trapezoid as shown in FIG. By performing such correction, the projected image 301 has less trapezoidal distortion.

  When the user confirms the screen and confirms that the image is still distorted, the user further operates the operation unit 102 to perform keystone correction. For example, if the keystone value is +10, the image processing unit 117 further deforms the image of the source image 402 as shown in FIG. By performing such correction, the projection image 401 has almost no trapezoidal distortion, and a projection image having a normal aspect ratio can be displayed.

  In this embodiment, manual keystone correction in which a keystone value is manually input has been described. However, it may be automatically performed according to the output of the tilt sensor 118. In this case, when the tilt sensor 118 detects that the projector 100 is tilted from the horizontal, the control unit 101 automatically sets a keystone value according to the tilt angle, and causes the image processing unit 117 to store the source image. Give instructions to transform.

  In the above description, the keystone value is set to a positive value, and the upper part of the shape of the source image is reduced. Conversely, when the keystone value is set to a negative value, the lower part of the shape of the source image is reduced.

  Next, the limitation of the keystone correction according to the present embodiment will be described.

  In this embodiment, a case will be described in which an image based on a file (information data) input from the USB interface unit 113, the card interface 114, the communication unit 115, the built-in memory 116, or the like is displayed. In this embodiment, a case will be described in which a keystone correction limit value (keystone limit value) is determined based on the type of input file (information data).

  FIG. 5 is a flowchart for explaining the keystone correction procedure of the projector according to the present embodiment.

  First, after the projection preparation of the projector is completed, for example, a file input by the card interface 114 is reproduced by the file reproduction unit 132. Then, the file reproduction unit 132 generates an image signal to be presented to the user from the reproduced file and outputs it to the image processing unit 117. The image processing unit 117 sends the input image signal to the liquid crystal driving unit 105 to project it on the screen.

  At this time, the control unit 101 determines the format of the file from the extension of the file reproduced by the file reproduction unit 132, the file data structure, the file header, and the like (S501).

  Next, the control unit 101 determines whether the file reproduced by the file reproduction unit 132 is an image file (S502). If the file is an image file (Yes in S502), the control unit 101 determines the keystone limit value to be ± 15, for example (S503). In order to determine whether the file is an image file, it may be determined that the extension is, for example, “.JPG” or “.GIF”. The image file includes files such as bitmap format, TIFF format, and PNG format. Note that these file formats are just an example.

  Next, when the file reproduced by the file reproduction unit 132 is not an image file (No in S502), the control unit 101 determines whether there is a presentation material file (S504). If it is a presentation material file (Yes in S504), the control unit 101 determines the keystone limit value to be ± 10, for example (S505). In order to determine whether the file format is a presentation material file, it may be determined that the extension is, for example, “.PPT”.

  Next, when the file reproduced by the file reproduction unit 132 is not a presentation material file (No in S504), the control unit 101 determines whether or not there is a document file (S506). If it is a document file (Yes in S506), the control unit 101 determines the keystone limit value to be ± 5, for example (S507). In order to determine whether the file is a document file, it may be determined that the extension is, for example, “.TXT” or “.DOC”.

  If the reproduced file is not a document file (No in S506), the control unit 101 does not determine a keystone limit value (S508).

  In this embodiment, the keystone limit value is determined according to the type of file (information data) reproduced in this way.

  After the keystone limit value is set, when the keystone correction is instructed by the operation unit 102 (S509), the following operation is performed.

  For example, when a document file is being reproduced, the keystone limit value is set to ± 5 (S507). When the keystone correction is instructed by the operation unit 102, for example, the keystone correction can be performed as usual up to the keystone value +5. However, if correction is to be made to the keystone value +5 or more, the control unit 101 generates a screen for notifying that the keystone limit value is exceeded on the projection screen, and transmits the screen to the image processing unit 117. To do. Then, a screen for selecting whether or not to restrict keystone correction is displayed at the same time.

  The user operates the operation unit 102 while viewing this display, and selects whether to restrict keystone correction or not (S510).

  When the keystone correction is limited (Yes in S510), the keystone value can be corrected within a range of ± 5, and further correction is prohibited (S511). When the keystone correction is not limited (No in S510), the keystone value can be set without limitation as before, and the keystone correction can be corrected to bring the projection screen closer to a rectangle (S512). . However, even if the keystone limit value is not set in S508, the keystone correction without the keystone correction limit is performed in S510 without displaying the selection screen (S512).

  Until the reproduction of the file ends (S513), each time the keystone correction is instructed, it is selected whether the keystone correction is restricted or not restricted (S510).

  As described above, in this embodiment, when it is determined that the file is an image file, when it is determined that it is a document file, or when it is determined that it is a presentation material file, the keystone correction is limited. Yes. When it is determined that a document file or presentation material file that is likely to contain characters (text) is displayed, the degree of restriction of keystone correction is higher than when it is determined that the file is an image file. Is strengthening. Further, when it is determined that the file is a document file, there is a high possibility that characters smaller than the presentation material file will be displayed, and therefore the degree of restriction of the keystone correction is further strengthened. That is, when it is determined that the file is of the first type (including text), the operation of the keystone correction is more limited than when it is determined that the file is of the second type (image, video). The degree is strengthened.

  This is because, when performing keystone correction, if the character is reduced as in the case of a natural image or landscape image, the character image may be crushed and become unrecognizable. For this reason, when it is determined that the file is a document file or a presentation material file, the restriction rate of the keystone correction is increased so that characters cannot be read. Furthermore, if the size of the character is small, even if it is a portion that has been reduced by a little keystone correction, the character may become unreadable, so if it is determined that it is a document file, the keystone correction The limit rate is further increased.

  In this embodiment, the type of file is specified by checking the extension of the file. However, the extension of this file can be considered other than those described above, and the extension of the file registered by the user can be considered. You may make it confirm a child. Further, for example, the file type may be determined from the file extension, the file data structure, the file header, and the like.

  Further, a case will be described in which the keystone set value that has already been set is exceeded at the stage where the keystone limit value has been set. The control unit 101 displays a selection screen for performing keystone correction according to the keystone limit value set on the screen being projected, or maintaining the current keystone correction. The control unit 101 communicates with the image processing unit 117 so that the selection screen is displayed on the screen being projected. The image processing unit 117 can display the selection screen on the screen being projected by generating an image in which the selection screen is superimposed on the image of the file being played back by the control unit 101.

  When the user operates the operation unit 102, it is selected to perform keystone correction according to the set keystone limit value. Then, the control unit 101 instructs the image processing unit 117 to perform keystone correction according to the keystone limit value set. As a result, for example, the keystone correction for the image that has been subjected to the keystone correction of +10 is changed to the correction of +5. Further, when the user operates the operation unit 102, it is selected to maintain the current keystone correction. Then, the control unit 101 does not issue an instruction to particularly limit the keystone correction.

  In addition, a button for setting whether or not to limit the keystone correction may be provided in the operation unit 102, and each time the button is pressed, whether or not the keystone limit value is adopted may be switched. By doing this, when the keystone correction that is close to the rectangle is usually applied and the characters etc. are crushed and difficult to see, the user can operate this button to immediately display the image with the keystone restriction. Can be displayed. In other words, by pressing the button, the keystone correction value can be switched to the limit value, so that it is possible to immediately change the keystone correction value so that a person can easily recognize a character.

  Further, the limitation of the keystone correction when the keystone correction is automatically performed from the angle detected by the inclination sensor 118 will be described. For example, when it is detected that the camera is tilted upward by 10 degrees from the horizontal, but the document file is being reproduced, the keystone limit value is originally +5. In this case, since the document file is reproduced, the user may select a mode in which only the correction up to the keystone limit value is set and a mode in which the keystone can be set regardless of the limit value.

  Further, after determining that the file is not an image file (S502), the control unit 101 may further determine whether or not information on the font of the character is described in the file. In this case, if the character font is not described, the control means 101 ends the limit value setting flow without setting the keystone limit value. When a font of characters (text) is described, the control unit 101 acquires information on the minimum size font among the fonts, and sets a keystone limit value corresponding to the minimum size font. Specifically, for example, if the minimum size font is 8 points, the keystone limit value is set to ± 4, if it is 20 points, it is set to ± 10, and if it is 30 points, it is set to ± 15. If it is 31 points or more, the keystone limit value is not set.

  In this way, even when the control unit 101 determines that the file is a document file or a presentation material file, the keystone restriction ratio can be set in detail according to the font size.

  In addition, when the correction as shown in FIG. 4 is performed by the keystone correction, the rate at which the image is reduced increases as the projection screen moves upward in FIG. That is, it becomes more susceptible to the keystone correction as it goes upward in the projection screen. Therefore, when the character font is described, the control unit 101 further determines the display position of the character and sets a keystone limit value corresponding to the display position. For example, a case where only 20-point font characters are included will be described. If the character display position is in the upward direction of the projection screen of FIG. 4, the keystone limit value is set to about +10 to −15, and if it is an intermediate position, it is set to ± 12 and the downward direction If it is, set to +15 to -10.

  In this way, even when the control unit 101 determines that the file is a document file or a presentation material file, the keystone restriction ratio can be set in detail according to the character display position.

  Moreover, when the font of the character is described, the control unit 101 may set the keystone limit value according to the character size and the display position. That is, when the minimum size font of the text is 20 points, the limit value is ± 10, but when the display position is the intermediate position, the limit value is determined to be ± 12.

  In this way, even when the control unit 101 determines that the file is a document file or a presentation material file, the keystone restriction ratio can be set in more detail according to the character size and display position. Can do.

  In this embodiment, the case where an instruction is issued by the operation unit 102 has been described. However, the instruction may be issued based on a control signal input to the infrared light receiving units 121 and 122.

  In this embodiment, a projector with a built-in liquid crystal panel has been described. However, even a projector with a built-in DMD panel may be applied to any display device that requires keystone correction. can do.

  In the first embodiment, the keystone correction is limited when a specific type of file is being played back. In the projector of this embodiment, in addition to the file format data, an image signal can be input from the analog input unit 110, the digital input unit 112, and the communication unit 115 and displayed. Therefore, the present embodiment is different from the first embodiment in that the spatial frequency of the projection image is detected and the keystone correction is limited based on the detected maximum value of the spatial frequency.

  The projector of this embodiment has the same configuration as the projector shown in FIG.

  Next, the limitation of the keystone correction process of this embodiment will be described.

  In the present embodiment, a limitation on keystone correction when video data acquired from the analog input unit 110 and the digital input unit 112 is reproduced will be described.

  FIG. 6 is a diagram illustrating an image input to the image processing unit 117 according to the present exemplary embodiment. In FIG. 6, reference numerals 601, 602, and 603 denote an upper part, a middle part, and a lower part of the image, respectively. In the present embodiment, the control unit 101 performs frequency analysis of an image in units of these areas.

  In the example of FIG. 6, since a character is included in the region 601, a high frequency component is detected in the region 601 by performing frequency analysis.

  An image including a high-frequency component may be unreadable due to, for example, illegible characters or image quality degradation due to the collapse of the image that has been reduced by the keystone correction.

  In addition, when the correction as shown in FIG. 4 is performed by the keystone correction, the rate at which the image is reduced increases as the projection screen moves upward in FIG. That is, it becomes more susceptible to the keystone correction as it goes upward in the projection screen.

  Therefore, when the correction shown in FIG. 4 is to be performed, in this embodiment, the keystone limit value set by the control unit 101 is set as follows.

  First, frequency analysis of the regions 601 602 603 is performed to detect the maximum frequency of each region. Then, in the example of FIG. 6, a high frequency component is detected in the region 601.

  That is, since the maximum frequency component is detected in the upper area of the projection screen, the keystone limit value is set to about +5 to -15.

  Similarly, when it is detected that the maximum high frequency component is included in the intermediate area, it is set to ± 7. When it is detected that the maximum high frequency component is included in the downward area, it is set to +15 to −5. When the maximum high frequency component in the upper region and the maximum high frequency component in the lower region are both about the same, ± 5 is set.

  By setting the keystone limit value in this way, it becomes possible to apply a keystone limit according to the nature of the image.

  In this embodiment, the frequency analysis was performed for each of the upper part, middle part, and lower part of the image. However, the frequency analysis may be performed for the left part, middle part, and right part of the image, and the region is finely divided throughout the entire image. The frequency analysis may be performed separately.

  By doing so, it is possible to know in detail which part of the image contains the high-frequency component, and it is possible to set the keystone limit value in detail. And even if it is a natural picture containing a character and a high frequency component, each image will not deteriorate violently.

  In this embodiment, the keystone limit value is set depending on the presence / absence of a high-frequency component, but a keystone limit value corresponding to the magnitude of the maximum frequency obtained by frequency analysis may be set. For example, it is assumed that a character is included in the region 601 and the other region is a non-character image. When the maximum frequency Wmax of the region 601 is larger than W1, the control unit 101 sets the keystone limit value to +5 to −15, and when it is between W1 and W2, it sets +6 to −15. Similarly, the keystone limit values are set in the order of +7 to −15 when it is between W2 and W3, and +8 to −15 when it is between W3 and W4.

  If the maximum frequency of the region 603 is between W3 and W4 and the maximum frequency of the region 601 is greater than W1, the keystone limit value is set to +5 to −8.

  In this way, by setting the keystone limit value, it is possible to limit the keystone according to the contrast of the image.

  When detecting the maximum frequency, a frequency value having a certain amplitude level or more may be regarded as the maximum frequency in order to avoid erroneous detection due to the influence of noise.

  Further, the same operation is performed for the restriction of the keystone correction when a file is reproduced and projected from the USB interface unit 113, the card interface 114, the communication unit 115, the built-in memory 116, or the like.

  In this embodiment, the case where an instruction is issued by the operation unit 102 has been described. However, the instruction may be issued based on a control signal input to the infrared light receiving units 121 and 122.

  In this embodiment, a projector with a built-in liquid crystal panel has been described. However, a projector with a built-in DMD panel may have any form as long as it is a display device that requires keystone correction. Can also be applied.

  Further, it may be appropriately combined with the first embodiment.

(Other examples)
It goes without saying that the object of the present invention can also be achieved by supplying a storage medium storing software program codes for realizing the functions of the above-described embodiments to the apparatus. At this time, the computer (or CPU or MPU) including the control unit of the supplied apparatus reads and executes the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing the program code constitute the present invention.

  As a storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, the OS (basic system or operating system) running on the apparatus performs part or all of the processing based on the instruction of the program code described above, and the functions of the above-described embodiments are realized by the processing. Needless to say, cases are also included.

  Further, the program code read from the storage medium may be written into a memory provided in a function expansion board inserted into the apparatus or a function expansion unit connected to the computer, and the functions of the above-described embodiments may be realized. Needless to say, it is included. At this time, based on the instruction of the program code, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing.

It is a block diagram of a liquid crystal projector to which the present invention is applied. It is a figure for demonstrating the keystone of a projector. It is a figure for demonstrating the keystone of a projector. It is a figure for demonstrating the keystone of a projector. It is a flowchart of the keystone limit value setting of the projector of Example 1. FIG. FIG. 6 is a diagram for explaining a frequency analysis region of Example 2.

Claims (3)

Projection means for projecting an image of information data onto a screen;
Keystone correction means for deforming the shape of the image projected by the projection means;
Determining means for determining the type of the information data;
Wherein according to the type of information data determined by the determining means, have a control means for determining the degree of limitation of the deformation of the shape of the image by the keystone correction unit,
The determination means determines the display position of the text when the information data is a file containing text,
The projection apparatus according to claim 1, wherein the control unit determines a degree of restriction of deformation of the shape of the image by the keystone correction unit according to the display position of the text determined by the determination unit. When the control means determines that the information data is a file containing text, the degree of restriction on the deformation of the image shape by the keystone correction means is greater than when the information data is determined to be an image file. The projection apparatus according to claim 1, wherein: The determining means determines the size of the text when the information data is a file including text,
Said control means, said depending on the size of the determined text by determining means, the keystone correction unit projection device according to claim 1, wherein the determining the degree of limitation of the deformation of the shape of the image by.

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