JP2011082663A - Projection type video display device, and image distortion correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent reduction in sharpness of a projection image when image distortion is corrected, in a projection type video display device. <P>SOLUTION: The projection type video display device includes: a solid-state light source; a projection element formed to vibrate in the horizontal and vertical directions for projecting an image on a projection surface by scanning light emitted from the solid-state light source along a scanning direction; and an image distortion correction unit for correcting image distortion in at least one of the horizontal direction and the vertical direction. The image distortion correction unit includes: an adjustment instruction unit for setting the amount of correction of the image distortion in the horizontal and vertical directions in accordance with an adjustment signal for adjusting the image projected on the projection surface; and a projection element drive unit for changing the scanning direction of the projection element in accordance with the amount of correction of the image distortion in the horizontal and vertical directions set by the adjustment instruction unit, and controlling the scanning width of the projection element in the scanning direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a projection display apparatus and an image distortion correction method, and more particularly to a projection display apparatus and an image distortion correction method having an image distortion correction function.

  In a projection display apparatus (hereinafter also referred to as a projector), an image projected on a projection surface is projected in a horizontal direction and a relative inclination between an optical axis of projection light from the projector and a projection surface such as a screen. There is a case where so-called image distortion occurs, that is, distortion in at least one direction of the vertical direction.

  As a projector having a correction function for correcting such image distortion, for example, in Japanese Patent Laid-Open No. 2002-158946 (Patent Document 1), when a user presses a two-dimensional operation button provided on a remote controller, A configuration is disclosed in which an image signal representing an image to be projected by a projector is adjusted by setting a horizontal correction parameter and a vertical correction parameter while viewing a distorted image displayed on a screen.

  Japanese Patent Laid-Open No. 2008-277953 (Patent Document 2) discloses that a regular shape (rectangular shape) is formed by forming an image distorted so as to cancel the trapezoidal distortion when an image is formed by a light modulation device. ) Discloses a configuration for displaying an image. In this Patent Document 2, the trapezoidal distortion correction is performed by thinning out pixels from image data, that is, by thinning out pixel values that define the gradation of each pixel, so that the input image has a higher direction than when no correction is performed. It is performed so that it reduces as it goes to.

JP 2002-158946 A JP 2008-277753 A

  However, in the correction of image distortion disclosed in the above-mentioned patent document, in order to form an image having a shape in which the width in the horizontal direction is reduced toward the tilting direction (tilting direction) of the projector, the image data is subjected to tilt projection. The position where the degree of enlargement is high is configured to thin out more pixel values. For this reason, in the projected image displayed on the projection surface, although the distortion of the image is corrected, the gradation is not generated on the side where the degree of enlargement by tilt projection is high, so-called gradation collapse occurs, and the image is uncomfortable. There was a problem of becoming.

  Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to prevent a reduction in sharpness of a projected image associated with image distortion correction processing in a projection display apparatus. It is.

  According to an aspect of the present invention, the projection display apparatus is configured to vibrate in a horizontal direction and a vertical direction with a solid-state light source, and scans the emitted light from the solid-state light source along the scanning direction. A projection element that projects an image on a surface, and an image distortion correction unit for correcting image distortion that occurs in at least one of a horizontal direction and a vertical direction. The image distortion correction unit is set by an adjustment instruction unit that sets a correction amount of image distortion in the horizontal direction and the vertical direction according to an adjustment signal for adjusting an image projected on the projection surface, and an adjustment instruction unit. And a projection element driving unit that changes the scanning direction of the projection element in accordance with the correction amount of the image distortion in the horizontal direction and the vertical direction, and controls the scanning width of the projection element in the scanning direction.

  Preferably, the image distortion correction unit further includes an image signal correction unit that reduces the image to be scanned by the projection element in the image distortion direction by thinning out the pixel value from the image input signal. The adjustment instruction unit compares the correction amount of the image distortion in the horizontal direction with the correction amount of the image distortion in the vertical direction. The projection element driving unit changes the image distortion direction corresponding to the relatively large correction amount to the scanning direction based on the comparison result of the adjustment instruction unit, and projects in the scanning direction according to the relatively large correction amount. Control the scanning width of the element. The image signal correction unit reduces the image to be scanned by the projection element in the direction of image distortion corresponding to a relatively small correction amount based on the comparison result of the adjustment instruction unit.

  Preferably, the image distortion correction unit further includes a signal analysis unit that analyzes a signal value for each pixel in the image input signal by using a relative inclination between the projection element and the projection surface. The adjustment instruction unit takes into account the amount of horizontal image distortion correction that takes into account the signal analysis result using the relative inclination in the horizontal direction, and the signal analysis result that uses the relative inclination in the vertical direction. The amount of vertical image distortion correction is compared.

  Preferably, the image distortion correction unit further includes a frequency analysis unit that analyzes a horizontal spatial frequency and a vertical spatial frequency from a signal value for each pixel in the image input signal. The adjustment instructing unit compares the horizontal image distortion correction amount in consideration of the horizontal spatial frequency with the vertical image distortion correction amount in consideration of the vertical spatial frequency.

  Preferably, the adjustment signal is a signal input to the image distortion correction unit from an adjustment tool used for image distortion correction. The image distortion correction unit further includes a display unit that displays an auxiliary line for assisting the adjustment operation in the adjustment tool on the projection plane.

  According to another aspect of the present invention, there is provided an image distortion correction method for a projection display apparatus for correcting image distortion that occurs in at least one of a horizontal direction and a vertical direction, and the projection display apparatus includes: A solid light source and a projection element configured to vibrate in the horizontal direction and the vertical direction and projecting an image on a projection surface by scanning light emitted from the solid light source along the scanning direction are included. In the image distortion correction method, the horizontal and vertical image distortion correction amounts are set according to the adjustment signal for adjusting the image projected on the projection surface, and the horizontal level set by the setting step is set. And changing the scanning direction of the projection element according to the correction amount of the image distortion in the direction and the vertical direction, and controlling the scanning width of the projection element in the scanning direction.

  According to the present invention, in the projection display apparatus, it is possible to prevent the sharpness of the projected image from being lowered due to the image distortion correction processing.

It is a figure which shows the structure of the projection type video display apparatus concerning Embodiment 1 of this invention. It is a figure which shows schematic structure of the projector in FIG. It is a figure explaining the structural example of the horizontal direction adjustment tool in FIG. 2, and a vertical direction adjustment tool. It is a figure which shows the state which is not performing image distortion correction. It is a figure explaining horizontal image distortion correction. It is a figure which shows the drive waveform of a projection element. It is a figure explaining the horizontal image distortion correction performed when performing vertical projection in the vertical direction (downward). It is a figure explaining the vertical image distortion correction | amendment performed when tilting in a horizontal direction (right direction). It is a flowchart for demonstrating the image distortion correction process according to Embodiment 1 of this invention. It is a figure explaining the image distortion correction | amendment performed when performing a horizontal projection in both a horizontal direction and a perpendicular direction. It is a flowchart for demonstrating the image distortion correction process according to Embodiment 2 of this invention. It is a figure explaining the image distortion correction process according to Embodiment 3 of this invention. It is a flowchart for demonstrating the image distortion correction process according to Embodiment 3 of this invention. It is a figure explaining the relationship between the relative inclination of a projector, and a weighting coefficient. It is a figure explaining the image distortion correction process according to Embodiment 3 of this invention. It is a flowchart for demonstrating the image distortion correction process according to Embodiment 4 of this invention. It is a figure explaining the structural example of a high pass filter. It is a figure explaining the image distortion correction process according to Embodiment 5 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a diagram showing a configuration of a projection display apparatus according to Embodiment 1 of the present invention.

  Referring to FIG. 1, a projection display apparatus (hereinafter also referred to as “projector”) PJ projects image light onto projection plane SC. The projection surface SC is not limited to a screen, and may be a wall surface. When the projector PJ projects horizontally, the projection image 300 displayed on the projection screen SC has a regular shape (rectangular shape) that maintains the aspect ratio of the image data input to the projector PJ.

FIG. 2 is a diagram showing a schematic configuration of the projector PJ in FIG.
Referring to FIG. 2, projector PJ is a scanning projector that scans an image to be displayed with light emitted from solid light source 152 and displays an image on projection surface SC. The projector PJ includes an image supply unit 200 that supplies an image signal to be displayed, and an image display unit 100 that displays the supplied image signal on the projection screen SC.

  The image supply unit 200 includes a frame memory 251, a driver 252, and a display unit 253.

  The frame memory 251 stores image data input via an input interface (not shown). The image data input to the image supply unit 200 is composed of image data in units of frames. The frame rate, which is a value indicating the number of times the screen is updated per second, is generally 60 frames / second for existing contents. That is, the time per frame (hereinafter also referred to as a frame period) is set to 1/60 sec.

  The driver 252 outputs the frame unit image data to the image display unit 100. The image data given to the image display unit 100 is input to the image processing unit 151.

  The display unit 253 displays an image of one frame based on the image data stored in the frame memory 251. Note that the image displayed on the display unit 253 is preferably synchronized with the image projected on the projection surface SC.

  The image display unit 100 includes an image processing unit 151, a solid light source 152, a solid light source driving unit 153, a projection element 154, and an adjustment instruction unit 110.

  The image processing unit 151 performs predetermined processing on the input image data to generate an image signal, and outputs the generated image signal to the solid-state light source driving unit 153. The image signal output from the image processing unit 151 includes a signal for defining the scanning timing of the gradation signal, as well as a gradation signal (RGB signal) indicating the gradation of the image to be displayed.

  The image signal is generated for each color light and includes a plurality of pixel values corresponding to all the pixels in the effective pixel area of the projection element 154. The pixel value determines the brightness of the corresponding pixel, and the gradation of each pixel is defined by this pixel value.

  The solid light source drive unit 153 controls the drive current applied to each color light source of the solid light source 152 according to the image signal. Thereby, the emitted light quantity of each color light source is controlled so that the brightness | luminance according to the gradation requested | required of the image which should be displayed is obtained.

  The solid light source 152 includes an LED (Laser Emitting Diode), an LD (Laser Diode), and the like. Although not shown, the solid light source 152 includes a red light source, a green light source, and a blue light source. Each color light source may be an array light source composed of a plurality of solid state light sources. Each color light source supplies light modulated in accordance with an image signal. In FIG. 2, for easy understanding, the light supplied from the solid-state light source 152 shows only light of a single color, and illustration of light of other colors is omitted.

  The light from the solid light source 152 enters the projection element 154. As an example, the projection element 154 includes a galvanometer mirror that vibrates a reflection surface around a predetermined axis. The light emitted from the solid light source 152 is reflected by the projection element 154 toward the projection plane SC. Thereby, a screen is displayed for each frame on the projection surface SC. It is assumed that the screen of one frame is a two-dimensional coordinate plane having an origin 0 defined by two orthogonal axes (horizontal axis and vertical axis). One pixel of the frame is indicated by coordinates (h, v).

  In screen display, the projection element 154 vibrates the reflecting surface in the vertical direction around an axis extending in the horizontal direction, and vibrates the reflecting surface in the horizontal direction around the axis extending in the vertical direction. As described above, the projection element 154 is vibrated in the vertical direction and the horizontal direction, respectively, so that the horizontal screen scanning is sequentially performed one line at a time in the vertical direction, and one screen (one frame) is obtained by one vertical scanning. Is drawing.

  Although not shown, the projection element driving unit 155 includes a vertical drive control unit that drives the projection element 154 to vibrate in the vertical direction, and a horizontal drive control unit that drives the projection element 154 to vibrate in the horizontal direction. including.

  When a signal having a frequency defining driving of the projection element 154 in the vertical direction (hereinafter, also referred to as “vertical drive signal”) is given from the image processing unit 151, the vertical drive control unit is based on the vertical drive signal. The projection element 154 is driven in the vertical direction. When a signal having a frequency defining the horizontal driving of the projection element 154 (hereinafter also referred to as “horizontal drive signal”) is given from the image processing unit 151, the horizontal drive control unit is based on the horizontal drive signal. The projection element 154 is driven in the horizontal direction.

  The vertical drive frequency and the horizontal drive frequency are defined in advance based on the size of the projection element 154, the projection direction, and the behavior characteristics of the projection element drive unit 155. The projection element driving unit 155 controls the swing angle of the projection element 154 with the driving frequency, whereby the projection image 300 can be displayed on the projection screen SC as shown in FIG.

  Here, when tilt projection is performed on the projection plane SC, that is, when an image is projected with the projector PJ tilted with respect to the projection plane SC, the projected image 300 is distorted to expand in the tilt direction (image). Distortion).

  As an image distortion correction function for correcting such image distortion, the projector PJ further includes a horizontal direction adjustment tool 112 and a vertical direction adjustment tool 113.

  The horizontal direction adjustment tool 112 is used to correct image distortion that occurs when being projected in the vertical direction. Specifically, when an image is projected in a state tilted in the vertical direction (vertical direction) from the normal line of the projection plane SC, the projected image 300 includes a trapezoidal image having different upper and lower lengths. Distortion occurs. Hereinafter, such image distortion correction is also referred to as “horizontal image distortion correction”.

  The vertical adjustment tool 113 is used to correct image distortion that occurs when the projector is projected in the horizontal direction. Specifically, when an image is projected in a state tilted in the horizontal direction (left-right direction) from the normal line of the projection plane SC, the projected image 300 has a horizontal trapezoidal shape in which the lengths of the left side and the right side are different. Image distortion occurs. Hereinafter, such image distortion correction is also referred to as “vertical image distortion correction”.

  In the present embodiment, as an example, horizontal adjustment tool 112 and vertical adjustment tool 113 are provided in remote controller (remote controller) 120 for remotely operating projector PJ. FIG. 3 is a diagram for explaining a configuration example of the horizontal direction adjustment tool 112 and the vertical direction adjustment tool 113 in FIG. Referring to FIG. 3, horizontal adjustment tool 112 includes operation buttons 112 </ b> R and 112 </ b> L provided on remote controller 120.

  The operation buttons 112R and 112L output an infrared horizontal direction adjustment signal in response to a user operation (pressing down). Specifically, the horizontal direction adjustment signal corresponds to a distortion correction amount in horizontal image distortion correction (hereinafter also referred to as “horizontal distortion correction amount”), and when the user presses the operation button 112R, the horizontal distortion signal is corrected. The correction amount increases upward. Thus, the upper side of the projection image 300 is corrected in a direction that is longer than the lower side. On the other hand, when the user presses the operation button 112L, the horizontal distortion correction amount increases downward. As a result, the lower side of the projected image 300 is corrected in a direction that is longer than the upper side.

  The vertical adjustment tool 113 includes operation buttons 113U and 113D provided on the remote controller 120. The operation buttons 113U and 113D output an infrared vertical adjustment signal in response to a user operation (pressing). Specifically, the vertical direction adjustment signal corresponds to a distortion correction amount in vertical image distortion correction (hereinafter also referred to as “vertical distortion correction amount”), and when the user presses the operation button 113U, the vertical distortion signal is corrected. The correction amount increases to the right. As a result, the right side of the projected image 300 is corrected in a direction that is longer than the left side. On the other hand, when the user presses the operation button 113D, the vertical distortion correction amount increases in the left direction. As a result, the left side of the projected image 300 is corrected in a direction that is longer than the right side.

  Referring again to FIG. 2, the horizontal direction adjustment signal and the vertical direction adjustment signal issued from remote controller 120 are provided to adjustment instruction unit 110 in image display unit 100. The adjustment instruction unit 110 performs image distortion correction processing according to the horizontal direction adjustment signal and the vertical direction adjustment signal.

[Image distortion correction]
Next, image distortion correction processing in the adjustment instruction unit 110 will be described with reference to FIGS. FIG. 4 is a diagram illustrating a state in which image distortion correction is not performed.

  Referring to FIG. 4A, when projector PJ is installed horizontally and performs projection without tilting, projected image 300 displayed on projection surface SC is the same as the image data input to image processing unit 151. A rectangular aspect ratio.

  On the other hand, when the projector PJ projects in the vertical direction (upward), the projection image 300 displayed on the projection screen SC is upward as shown in FIG. 4B. Enlarged and distorted into a trapezoidal shape.

  In FIG. 4, the left-right direction toward the projection plane SC is defined as the horizontal direction (H direction), and the up-down direction is defined as the vertical direction (V direction). The horizontal direction and the vertical direction of the projection surface SC correspond to the horizontal direction and the vertical direction of the projection element 154 (FIG. 2), respectively.

(Horizontal image distortion correction)
FIG. 5 is a diagram for explaining horizontal image distortion correction. FIG. 5A shows an image (hereinafter also referred to as “scanned image”) scanned by the projection element 154 when projection is performed in the vertical direction (upward direction) shown in FIG. It is. FIG. 5B is a diagram showing a projected image 300 displayed on the projection screen SC corresponding to the scanned image 400 of FIG.

  Referring to FIG. 5A, the projection element driving unit 155 (FIG. 2) scans the projection element 154 in the scanning direction (horizontal direction) according to the horizontal distortion correction amount specified by the horizontal direction adjustment signal. To control. Thereby, as compared with the case where the horizontal image distortion correction is not performed, correction is performed such that the scanning image 400 is reduced in the horizontal direction as it goes in the vertical direction (upward). That is, the projection element driving unit 155 causes the projection element 154 to form a trapezoidal scanning image 400 in the opposite direction that can cancel the trapezoidal image distortion (FIG. 4B) of the projection image 300.

  FIG. 6 shows a driving waveform of the projection element 154. In the figure, the drive frequency of the vertical drive signal (line k1 in the figure) and the horizontal drive signal (line k2 in the figure) is based on the size of the projection element 154, the projection direction, and the behavior characteristics of the projection element drive unit 155. Are prescribed in advance. The projection element driving unit 155 controls the swing angle of the projection element 154 with the driving frequency, thereby scanning an image for each frame.

  Specifically, the drive signal can be decomposed into a frequency component and an amplitude component. In the default setting, the frequency component of the vertical drive signal is once per frame, and the amplitude component is a signal value substantially corresponding to the size of the projection image 300 in the vertical direction (V direction). The frequency component (line k2 in the figure) of the horizontal drive signal is the number of pixels (number of lines) in the V direction of the projected image 300 per frame, and the amplitude component is in the horizontal direction (H direction) of the projected image 300. It is a constant signal value approximately corresponding to the magnitude.

  When the horizontal image distortion correction as shown in FIG. 5A is performed, the projection element driving unit 155 gradually increases the amplitude component (line k3 in the drawing) of the horizontal drive signal, thereby projecting the projection element. The horizontal drive signal 154 (line k4 in the figure) is gradually increased. As a result, the scanning width of the projection element 154 is narrowed toward the tilt direction (upward), so that the scan image 400 having a shape in which the width in the horizontal direction is reduced toward the tilt direction is formed. As a result, as shown in FIG. 5B, the projection image 300 displayed on the projection screen SC has a rectangular shape in which the aspect ratio of the input image data is maintained.

  The amplitude component of the horizontal drive signal is controlled for each frame according to the horizontal correction distortion correction amount specified by the horizontal direction adjustment signal. In this way, the control for changing the amplitude component of the drive signal of the projection element 154 is also referred to as “amplitude control” of the projection element 154 below.

  As described above, the image distortion correction processing according to the present embodiment is configured such that the scanning width of the projection element 154 in the scanning direction is controlled according to the distortion correction amount in the scanning direction, so that pixel values are thinned out from the image data. Compared with the conventional image distortion correction processing that performs the above, it is possible to prevent the occurrence of gradation collapse in the projected image.

  That is, in the image distortion correction processing so far, in order to set an image forming area having a shape in which the width in the horizontal direction is reduced as it goes in the tilt direction, from the image data, the position where the degree of enlargement by tilt projection is high The pixel value is thinned out. Therefore, in the projected image, the distortion of the image is corrected, but the gradation is not generated on the side where the degree of enlargement by tilt projection is high, so-called gradation collapse occurs, and the image becomes uncomfortable. Has occurred.

  On the other hand, in the image distortion correction processing according to the present embodiment, since the scan width of the scan image is corrected so that the position of the enlargement by tilt projection is reduced, the pixel between the image data and the scan image is corrected. There is no change in value. For this reason, occurrence of gradation collapse can be suppressed, and a smooth image can be realized.

  FIG. 7 is a diagram for explaining horizontal image distortion correction executed when vertical projection is performed in the vertical direction (downward). Note that when performing vertical projection in the vertical direction (downward), the projected image 300 displayed on the projection screen SC is enlarged downward and distorted into a trapezoidal shape.

  In this case, the projection element driving unit 155 gradually decreases the horizontal drive signal (line k4 in the figure) of the projection element 154 by gradually reducing the amplitude component (line k3 in the figure) of the horizontal drive signal. . As a result, the scanning width of the projection element 154 is narrowed toward the tilt direction (downward), so that the scan image 400 having a shape in which the width in the horizontal direction is reduced toward the tilt direction is formed. As a result, the projected image 300 displayed on the projection screen SC has a rectangular shape that maintains the aspect ratio of the input image data.

(Vertical image distortion correction)
FIG. 8 is a diagram for explaining vertical image distortion correction executed when projection is performed in the horizontal direction (right direction). Although illustration is omitted, when projection is performed in the horizontal direction (right direction), the projection image 300 displayed on the projection screen SC is enlarged in the right direction and distorted into a horizontal trapezoidal shape.

  In this case, the projection element driving unit 155 switches the scanning direction of the projection element 154 from the horizontal direction to the vertical direction according to the vertical distortion correction amount specified by the vertical direction adjustment signal, and also scans the projection element 154 in the scanning direction ( Controls the scanning width in the vertical direction. Specifically, the projection element driving unit 155 gradually reduces the vertical drive signal (line k6 in the figure) of the projection element 154 by gradually decreasing the amplitude component (line k5 in the figure) of the vertical drive signal. Decrease. As a result, a scanned image 400 having a shape in which the width in the vertical direction is reduced toward the tilt direction (right direction) is formed. As a result, the projected image 300 displayed on the projection screen SC has a rectangular shape that maintains the aspect ratio of the input image data.

(Processing flow)
FIG. 9 is a flowchart for illustrating the image distortion correction processing according to the first embodiment of the present invention. This image distortion correction process is a process executed for each frame by the image display unit 100 (FIG. 2).

Referring to FIG. 9, first, adjustment instruction unit 110 determines whether or not a horizontal direction adjustment signal issued from horizontal direction adjustment tool 112 of remote controller 120 has been detected (step S01). When the horizontal adjustment signal is determined to have been detected (YES in step S01), the adjustment instruction unit 110 sets the horizontal distortion correction amount C _H in response to the horizontal adjustment signal (step S02), and the setting and it outputs the horizontal distortion correction amount C _H to the projection device driving section 155. This instructs the projection element driving unit 155 to control the amplitude in the horizontal direction (H direction) of the projection element 154 (step S03).

Projection device driving section 155 in accordance with the horizontal distortion correction amount C _H input to set the oscillation angle of the mirror provided in the projection device 154. Specifically, the projection element driving unit 155, as shown in FIGS. 6 and 7, in accordance with the horizontal distortion correction amount C _H, sets the amplitude components of the horizontal driving signals of the projection device 154 (step S04) .

  When receiving the vertical drive signal and the horizontal drive signal from the image processing unit 151, the projection element driving unit 155 drives the projection element 154 in the vertical direction and the horizontal direction based on these drive signals (step S05). At this time, the swing angle of the projection element 154 in the horizontal direction is controlled to change according to the amplitude component of the horizontal drive signal of the projection element 154 set in step S04. As a result, a scanned image 400 (FIG. 6 or FIG. 7) having a shape in which the width in the horizontal direction is reduced toward the tilt direction is formed.

  Returning to step S01 again, if it is determined that the horizontal adjustment signal has not been detected (NO in step S01), adjustment instruction unit 110 is further issued from vertical adjustment tool 113 of remote controller 120. It is determined whether a vertical adjustment signal is detected (step S06). When it is determined that the vertical adjustment signal has not been detected (NO in step S06), the projected image 300 displayed on the projection screen SC retains the original aspect ratio of the image data, and image distortion occurs. It is determined that the image has not occurred, and the series of image distortion correction processing is terminated.

On the other hand, when it is determined that a vertical adjustment signal has been detected (YES in step S06), adjustment instruction unit 110 sets vertical distortion correction amount C _V in accordance with the vertical adjustment signal (step S07). The set vertical distortion correction amount _CV is output to the projection element driving unit 155. This instructs the projection element driving unit 155 to control the amplitude of the projection element 154 in the vertical direction (V direction) (step S08).

The projection element driving unit 155 sets the swing angle of the mirror provided in the projection element 154 according to the input vertical distortion correction amount _CV . Specifically, as shown in FIG. 8, the projection element driving unit 155 sets the amplitude component of the vertical drive signal of the projection element 154 according to the vertical distortion correction amount _CV (step S09).

  When receiving the vertical drive signal and the horizontal drive signal from the image processing unit 151, the projection element driving unit 155 drives the projection element 154 in the vertical direction and the horizontal direction based on these drive signals (step S05). At this time, the swing angle of the projection element 154 in the vertical direction is controlled so as to change according to the amplitude component of the vertical drive signal of the projection element 154 set in step S09. Thus, a scanned image 400 (FIG. 8) having a shape in which the width in the vertical direction is reduced toward the tilt direction is formed.

  As described above, according to the first embodiment of the present invention, the horizontal amplitude control of the projection element 154 is performed in accordance with the horizontal distortion correction amount, and the vertical direction of the projection element 154 is in accordance with the vertical distortion correction amount. Directional amplitude control is performed. As described above, the scanning direction of the projection element 154 is changed according to the image distortion correction amount, and the scanning width in the changed scanning direction is controlled according to the image distortion correction amount, so that the pixel value is thinned out. It is possible to prevent gradation collapse due to the occurrence of the projected image. As a result, it is possible to realize a smooth image with sharpness maintained.

[Embodiment 2]
Next, image distortion correction processing according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 10 is a diagram for explaining image distortion correction executed when projection is performed in both the horizontal direction and the vertical direction (two-dimensional direction).

  FIG. 10A is a diagram illustrating a state in which image distortion correction is not performed. When the projector PJ performs tilting projection in the vertical direction (upward direction) and the horizontal direction (rightward direction), the projected image 300 displayed on the projection surface SC is enlarged in the upward direction and the right direction, respectively. Distorted.

  When the projection image 300 is thus distorted in the two-dimensional direction, the adjustment instruction unit 110 receives a horizontal direction adjustment signal issued from the horizontal direction adjustment tool 112 of the remote controller 120 and also from the vertical direction adjustment tool 113. When the generated vertical direction adjustment signal is received, the magnitudes of the horizontal distortion correction amount specified by the horizontal direction adjustment signal and the vertical distortion correction amount specified by the vertical direction adjustment signal are compared. Then, the amplitude control of the projection element 154 is executed in the direction in which the distortion correction amount is larger. On the other hand, pixel values are thinned out from image data in a direction in which the distortion correction amount is smaller. Hereinafter, correction for thinning out pixel values from image data is also referred to as “signal correction”.

  FIG. 10B shows a scanned image 400 formed by the projection element 154 by the image distortion correction process when the horizontal distortion correction amount is larger than the vertical distortion correction amount. For the horizontal direction where the amount of distortion correction is larger, horizontal amplitude control of the projection element 154 is executed as horizontal image distortion correction. That is, the scanning direction of the projection element 154 is changed to the horizontal direction, and the input current value of the projection element 154 in the scanning direction (horizontal direction) is changed in accordance with the horizontal distortion correction amount, whereby the tilt direction (upward direction). A scanned image 400 having a shape in which the width in the horizontal direction is reduced toward the left is formed.

  On the other hand, for the vertical direction where the distortion correction amount is smaller, signal correction is executed as vertical image distortion correction. Specifically, upon receiving the vertical distortion correction amount from the adjustment instruction unit 110, the image processing unit 151 (FIG. 2) thins out pixel values from the image data supplied from the image supply unit 200, thereby forming an image. Correction is performed such that the width in the vertical direction is reduced as the area moves in the vertical direction (right direction). At this time, for each pixel included in an area outside the image forming area (corresponding to a hatched area in the drawing), the image data is corrected so that the light transmittance is minimized. Thereby, light is hardly irradiated to the area | region in the scanning image 400 corresponding to the said area | region. As a result, the projected image 300 displayed on the projection screen SC has a rectangular shape that maintains the aspect ratio of the input image data.

  As described above, the horizontal distortion correction amount and the vertical distortion correction amount are compared, and the amplitude of the projection element 154 is controlled in a direction in which the distortion correction amount is larger. It is possible to prevent occurrence of gradation collapse due to thinning out many pixel values in proportion to the size. In addition, the signal correction is performed in the direction where the distortion correction amount is smaller. However, since the pixel values to be thinned out corresponding to the small distortion correction amount are small, the influence on the image quality degradation is minimized. Can be suppressed. As a result, an image having no sense of incongruity can be realized.

(Processing flow)
FIG. 11 is a flowchart for illustrating image distortion correction processing according to the second embodiment of the present invention. This image distortion correction process is a process executed for each frame by the image display unit 100 (FIG. 2).

  Referring to FIG. 11, first, adjustment instruction section 110 has detected a horizontal direction adjustment signal issued from horizontal direction adjustment tool 112 of remote controller 120 or a vertical direction adjustment signal issued from vertical direction adjustment tool 113. It is determined whether or not (step S11). When it is determined that neither the horizontal direction adjustment signal nor the vertical direction adjustment signal is detected (NO in step S11), the projected image 300 displayed on the projection screen SC retains the original aspect ratio of the image data. Therefore, it is determined that no image distortion has occurred, and a series of image distortion correction processing ends.

In contrast, when the horizontal adjustment signal or the vertical direction adjustment signal is determined to have been detected (YES in step S11), and adjustment instruction unit 110, the horizontal distortion correction amount C _H in response to the horizontal adjustment signal In addition to setting, a vertical distortion correction amount _CV is set according to the vertical direction adjustment signal (step S12).

Next, the adjustment instruction unit 110 compares the set horizontal distortion correction amount _CH with the vertical distortion correction amount _CV (step S13). If the horizontal distortion correction amount _{C H} greater than the vertical distortion correction values _{C V} (YES at step S13), and adjustment instruction unit 110 outputs the horizontal distortion correction amount _{C H} which is the set to the projection device driving section 155 To do. This instructs the projection element driving unit 155 to control the amplitude of the projection element 154 in the horizontal direction (H direction) (step S14).

Projection device driving section 155 in accordance with the horizontal distortion correction amount C _H input to set the oscillation angle of the mirror provided in the projection device 154. Specifically, the projection element driving unit 155 sets the amplitude component of the horizontal drive signal of the projection element 154 according to the horizontal distortion correction amount C _H (step S15).

In addition, the adjustment instruction unit 110 transmits the vertical distortion correction amount _CV set in step S12 to the image processing unit 151 (step S16). The image processing unit 151 thins out pixel values from the image data supplied from the image supply unit 200 in accordance with the vertical distortion correction amount _CV , so that the image forming region is vertical as it goes in the vertical direction (horizontal direction). Signal correction is performed to reduce the width in the direction (step S17).

  When receiving the vertical drive signal and the horizontal drive signal from the image processing unit 151, the projection element driving unit 155 drives the projection element 154 in the vertical and horizontal directions based on these drive signals (step S18). At this time, the swing angle of the projection element 154 in the horizontal direction is controlled to change according to the amplitude component of the horizontal drive signal of the projection element 154 set in step S15. As a result, a scanned image 400 having a shape in which the width in the horizontal direction is reduced toward the tilt direction (vertical direction) is formed. Further, with respect to the tilt direction (horizontal direction), the projected image 300 has an aspect ratio of input image data because almost no light is applied to the area in the scanned image 400 corresponding to the area outside the image forming area. Is displayed on the projection screen SC in a rectangular shape with

Returning to step S13 again, if the horizontal distortion correction amount _CH is equal to or less than the vertical distortion correction amount _CV (NO in step S13), the adjustment instruction unit 110 uses the set vertical distortion correction amount _CV . Output to the projection element driving unit 155. This instructs the projection element driving unit 155 to control the amplitude of the projection element 154 in the vertical direction (V direction) (step S19).

The projection element driving unit 155 sets the swing angle of the mirror provided in the projection element 154 according to the input vertical distortion correction amount _CV . Specifically, the projection element driving unit 155 sets the amplitude component of the vertical drive signal of the projection element 154 according to the vertical distortion correction amount _CV (step S20).

The adjustment instruction unit 110 transmits the horizontal distortion correction amount _{C H} set in step S12 to the image processing unit 151 (step S21). The image processing unit 151, in response to the horizontal distortion correction amount C _H, by performing the decimation of the pixel values from the image data supplied from the image supply unit 200, as directed toward the image forming region tilt (vertical) horizontal Signal correction is performed to reduce the width in the direction (step S22).

  When receiving the vertical drive signal and the horizontal drive signal from the image processing unit 151, the projection element driving unit 155 drives the projection element 154 in the vertical and horizontal directions based on these drive signals (step S18). At this time, the swing angle of the projection element 154 in the vertical direction is controlled to change according to the amplitude component of the vertical drive signal of the projection element 154 set in step S20. As a result, a scanned image 400 having a shape in which the width in the vertical direction is reduced toward the tilt direction (horizontal direction) is formed. Also, with respect to the tilt direction (vertical direction), since light is hardly irradiated to the area in the scanned image 400 corresponding to the area outside the image forming area, the projected image 300 has an aspect ratio of input image data. Is displayed on the projection screen SC in a rectangular shape with

  As described above, according to the second embodiment of the present invention, the amplitude control of the projection element 154 is performed in the direction in which the distortion correction amount is larger in accordance with the comparison result between the horizontal distortion correction amount and the vertical distortion correction amount. The signal correction is performed by thinning out pixel values from the image data in a direction in which the distortion correction amount is smaller. As a result, it is possible to minimize the occurrence of gradation collapse due to thinning of pixel values in the projected image, and thus it is possible to realize an image without a sense of incongruity.

[Embodiment 3]
As described in the second embodiment, when the amplitude control of the projection element 154 is performed in the direction in which the distortion correction amount is larger, the image data supplied from the image supply unit 200 has gradation. In a scene including a gradation portion that changes smoothly and continuously, there is a problem in that the brightness of the projected image is inevitably lowered depending on the relationship between the brightness of the image data and the depth difference of the projection surface SC.

  Regarding such a problem, as shown in FIG. 12A, a case where the image input from the image supply unit 200 is a gradation image whose gradation continuously changes along the horizontal direction (H direction). This will be described as an example. In the example of FIG. 12A, it is assumed that the gradation form of the input image becomes brighter from left to right along the horizontal direction.

  Here, when the projector PJ performs tilting projection in the vertical direction (upward direction) and the horizontal direction (leftward direction), the projected image 300 displayed on the projection surface SC is enlarged in the upward direction and the left direction, respectively. Distorted to the shape.

  At this time, the horizontal distortion correction amount is greater than the vertical distortion correction amount between the horizontal distortion correction amount specified by the horizontal direction adjustment signal issued from the remote controller 120 and the vertical distortion correction amount specified by the vertical direction adjustment signal. If the relationship is also large, the horizontal amplitude control of the projection element 154 is executed as the horizontal image distortion correction by the method described above. Further, signal correction is executed as vertical image distortion correction. As a result, as shown in the right diagram of FIG. 12B, a scanned image 400 having a shape in which the width in the horizontal direction is reduced toward the tilt direction (upward) is formed. Further, in the scan image 400, in the tilt direction (left direction), almost no light is applied to the area corresponding to the area outside the image forming area (corresponding to the hatched area in the figure).

  As a result, the projection image 300 displayed on the projection screen SC has a rectangular shape in which the aspect ratio of the input image data is maintained, as shown in the left diagram of FIG. However, on the other hand, the brightness of the gradation form in the projected image 300 changes from the original input image, resulting in a decrease in luminance. This is because, due to horizontal tilt projection, there is a depth difference that increases in distance from the right side to the left side on the projection surface SC viewed from the projector PJ, but on the right side of the gradation image by signal correction. This is because more pixel values are thinned out toward a brighter region, so that the amount of light per unit area of the region is reduced and the original luminance of the input image cannot be reproduced.

  In order to avoid such a problem, in the image distortion correction according to the present embodiment, the input image is analyzed, and the amplitude control of the projection element 154 is performed in consideration of the magnitudes of signal values of a plurality of pixels constituting the input image. And image signal signal correction are used separately.

  For example, in the case of the gradation image in FIG. 12A, signal correction is executed as horizontal image distortion correction, and vertical amplitude control of the projection element 154 is executed as vertical image distortion correction. As a result, as shown in the left diagram of FIG. 12C, a scanning image 400 having a shape in which the width in the vertical direction is reduced toward the tilt direction (left direction) is formed. In this scanned image 400, pixel values from the image data are thinned out only in the horizontal direction, so that there is no change in the pixel values in the bright area on the right side of the gradation image. Thereby, the light quantity per unit area of the said area | region is maintained, and the luminance fall by a depth difference can be prevented. As a result, the projected image 300 displayed on the projection surface SC reproduces the gradation form of the input image as shown in the right diagram of FIG.

(Processing flow)
FIG. 13 is a flowchart for illustrating image distortion correction processing according to the third embodiment of the present invention. This image distortion correction process is a process executed for each frame by the image display unit 100 (FIG. 2). The flowchart of FIG. 13 is the same as the flowchart of FIG. 11 described above, and differs only in that steps S120 to S121 are included instead of steps S13 and S14.

Referring to FIG. 13, when adjustment instruction unit 110 determines that a horizontal adjustment signal or a vertical adjustment signal has been detected (YES in step S11), adjustment instruction unit 110 responds to the horizontal adjustment signal. The horizontal distortion correction amount _CH is set, and the vertical distortion correction amount _CV is set according to the vertical direction adjustment signal (step S12).

  Next, the adjustment instruction unit 110 analyzes the signal value for each pixel in the input image signal using the relative inclination between the projector PJ and the projection surface SC. Based on this analysis result, a coefficient for adjusting the image distortion correction amount is calculated (step S120).

The calculation of the coefficient in step S120 is performed for each of the horizontal direction and the vertical direction. Specifically, the horizontal image signal value coefficients H _COEF for adjusting the horizontal image distortion correction amount C _H is, n pieces constituting the image data (n is a natural number) among the pixels of the, i-th (i is 1 or more When the signal value of a pixel having a natural number of n or less) is α (i), the pixel value is calculated by the equation (1).

In the above equation (1), the signal value α (i) of each pixel is multiplied by a weighting coefficient γ _H corresponding to the relative inclination in the horizontal direction between the projector PJ and the projection surface SC. FIG. 14A shows the relationship between the relative inclination d _H of the projector PJ in the horizontal direction and the weighting coefficient γ _H. Note that the relationship of FIG. 14A is adapted in advance through experiments or the like.

Referring to FIG. 14A, the weighting coefficient γ _H is set so as to increase as the relative inclination d _{H in} the horizontal direction increases. This is because as the relative inclination d _H in the horizontal direction increases, the depth difference in the horizontal direction in the projected image 300 increases, and the luminance tends to decrease.

By the same method, the vertical image signal value coefficient V _COEF for adjusting the vertical image distortion correction amount CV is calculated by the equation (2).

In the above formula (2), the signal value of each pixel alpha (i), the weighting coefficient gamma _V corresponding to the vertical direction of the relative tilt between the projector PJ and the projection plane SC is multiplied. In FIG. 14 (b), showing the relationship between the relative inclination d _V in the vertical direction of the projector PJ and the weighting coefficient gamma _V. Note that the relationship in FIG. 14B is adapted in advance through experiments or the like.

Referring to FIG. 14B, the weighting coefficient γ _V is set so as to increase as the relative inclination d _{V in} the vertical direction increases. The larger the relative inclination d _V in the vertical direction, the depth difference in the vertical direction becomes large in the projection image 300, due to the reduction in luminance is likely to occur.

Referring to FIG. 13 again, the adjustment instruction unit 110 multiplies the calculated horizontal image signal value coefficient H _COEF by the horizontal distortion correction amount C _H set in step S12, _{thereby obtaining} the horizontal distortion correction amount C _H. adjust. The adjustment instruction unit 110, the calculated vertical image signal value coefficients V _COEF, by multiplying the vertical distortion correction amount C _V set in step S12, adjusting the vertical distortion correction values C _V. Then, the adjustment instruction unit 110 _compares the adjusted horizontal distortion correction amount (C _H × H _COEF ) with the vertical distortion correction amount (C _V × V _COEF ) (step S121).

When the adjusted horizontal distortion correction amount C _H × H _COEF is larger than the adjusted vertical distortion correction amount C _V × V _COEF (YES in step S121), the adjustment instruction unit 110 is set in step S12. and it outputs the horizontal distortion correction amount C _H to the projection device driving section 155. This instructs the projection element driving unit 155 to control the amplitude of the projection element 154 in the horizontal direction (H direction) (step S14).

Projection device driving section 155 in accordance with the horizontal distortion correction amount C _H input to set the oscillation angle of the mirror provided in the projection device 154. Specifically, the projection element driving unit 155 sets the amplitude component of the horizontal drive signal of the projection element 154 according to the horizontal distortion correction amount C _H (step S15).

In addition, the adjustment instruction unit 110 transmits the vertical distortion correction amount _CV set in step S12 to the image processing unit 151 (step S16). The image processing unit 151 thins out pixel values from the image data supplied from the image supply unit 200 in accordance with the vertical distortion correction amount _CV , so that the image forming region is vertical as it goes in the vertical direction (horizontal direction). Signal correction is performed to reduce the width in the direction (step S17).

  When receiving the vertical drive signal and the horizontal drive signal from the image processing unit 151, the projection element driving unit 155 drives the projection element 154 in the vertical and horizontal directions based on these drive signals (step S18). At this time, the swing angle of the projection element 154 in the horizontal direction is controlled to change according to the amplitude component of the horizontal drive signal of the projection element 154 set in step S15.

Returning to step S121 again, if the adjusted horizontal distortion correction amount C _H × H _COEF is equal to or less than the adjusted vertical distortion correction amount C _V × V _COEF (NO in step S121), the adjustment instruction unit 110 Outputs the vertical distortion correction amount _CV set in step S12 to the projection element driving unit 155. This instructs the projection element driving unit 155 to control the amplitude of the projection element 154 in the vertical direction (V direction) (step S19).

The projection element driving unit 155 sets the swing angle of the mirror provided in the projection element 154 according to the input vertical distortion correction amount _CV . Specifically, the projection element driving unit 155 sets the amplitude component of the vertical drive signal of the projection element 154 according to the vertical distortion correction amount _CV (step S20).

The adjustment instruction unit 110 transmits the horizontal distortion correction amount _{C H} set in step S12 to the image processing unit 151 (step S21). The image processing unit 151, in response to the horizontal distortion correction amount C _H, by performing the decimation of the pixel values from the image data supplied from the image supply unit 200, as directed toward the image forming region tilt (vertical) horizontal Signal correction is performed to reduce the width in the direction (step S22).

  When receiving the vertical drive signal and the horizontal drive signal from the image processing unit 151, the projection element driving unit 155 drives the projection element 154 in the vertical and horizontal directions based on these drive signals (step S18).

  As described above, according to the third embodiment of the present invention, the horizontal distortion correction amount considering the analysis result of the image signal using the relative inclination in the horizontal direction, and the relative in the vertical direction. The vertical distortion correction amount considering the analysis result of the image signal using a simple inclination is compared, and the amplitude control of the projection element 154 and the signal correction of the image data are properly used according to the comparison result. That is, in the image distortion correction, the relationship between the brightness of the image data and the depth difference of the projection plane SC is taken into consideration. Accordingly, it is possible to prevent a decrease in luminance of the projected image that occurs due to the relationship. As a result, it is possible to realize image distortion correction for correcting an image to be displayed into a desired shape without impairing the sharpness of the image.

[Embodiment 4]
As described in the second embodiment, when the signal correction is performed by thinning out the pixel values in the direction in which the distortion correction amount is smaller, the spatial frequency characteristics of the image data supplied from the image supply unit 200 are used. Depending on the situation, there is a problem that the visibility of the projected image is remarkably lowered due to the occurrence of gradation collapse.

  With respect to such a problem, as shown in FIG. 15A, an image input from the image supply unit 200 repeatedly forms a black line and a white line extending in the horizontal direction (H direction) in the vertical direction (V direction). A case of a striped pattern (border image) will be described as an example.

  Here, when the projector PJ performs projection in the vertical direction (upward direction) and the horizontal direction (rightward direction), the projected image 300 displayed on the projection surface SC is enlarged in the upward direction and the right direction, respectively. Distorted to the shape.

  At this time, the horizontal distortion correction amount is greater than the vertical distortion correction amount between the horizontal distortion correction amount specified by the horizontal direction adjustment signal issued from the remote controller 120 and the vertical distortion correction amount specified by the vertical direction adjustment signal. If the relationship is also large, the horizontal amplitude control of the projection element 154 is executed as the horizontal image distortion correction by the method described in the second embodiment. Further, signal correction is executed as vertical image distortion correction. As a result, as shown in the left diagram of FIG. 15B, a scanned image 400 having a shape in which the width in the horizontal direction is reduced toward the tilt direction (upward) is formed. Further, in the scan image 400, in the tilt direction (right direction), light is hardly irradiated to a region (corresponding to a hatched region in the drawing) corresponding to a region outside the image forming region.

  Note that the boundary line between the black line and the white line extending in the horizontal direction on the scanned image 400 becomes rough because pixel values are thinned out in the vicinity of the boundary line by thinning out pixel values in the vertical direction. Yes.

  As a result, the projection image 300 displayed on the projection screen SC has a rectangular shape in which the aspect ratio of the input image data is maintained, as shown in the right diagram of FIG. However, on the other hand, the striped pattern cannot be accurately reproduced in the projected image 300 due to the influence of the pixel collapse described above.

  In order to avoid such inconvenience, in the image distortion correction according to the present embodiment, the spatial frequency of the input image is analyzed, and the amplitude control of the projection element 154 and the signal correction are selectively used in consideration of the obtained spatial frequency. And For example, in the case of the border image in FIG. 15A, the spatial frequency in the vertical direction is higher than the spatial frequency in the horizontal direction. Therefore, in such a case, image data signal correction is executed as horizontal image distortion correction, and vertical amplitude control of the projection element 154 is executed as vertical image distortion correction. As a result, as shown in the left diagram of FIG. 15C, a scanned image 400 having a shape in which the width in the vertical direction is reduced toward the tilt direction (right direction) is formed. In this scanned image 400, pixel values are thinned out from the image data only in the horizontal direction, so that no pixel collapse occurs on the boundary line between the black line and the white line on the scanned image 400. It is smooth.

  Note that pixel crushing occurs at both ends of the black line in the horizontal direction by thinning out the pixel values in the horizontal direction, but the area corresponding to the area outside the image forming area (corresponding to the hatched area in the figure) ), The projected image 300 is not affected.

  As a result, the projected image 300 displayed on the projection surface SC reproduces the striped pattern form of the input image as shown in the right diagram of FIG.

(Processing flow)
FIG. 16 is a flowchart for describing image distortion correction processing according to the fourth embodiment of the present invention. This image distortion correction process is a process executed for each frame by the image display unit 100 (FIG. 2). The flowchart in FIG. 16 is similar to the flowchart in FIG. 11 described above, and is different only in that steps S130 and S131 are included instead of steps S13 and S14.

Referring to FIG. 16, when adjustment instruction unit 110 determines that a horizontal direction adjustment signal or a vertical direction adjustment signal has been detected (YES in step S11), adjustment instruction unit 110 responds to the horizontal direction adjustment signal. The horizontal distortion correction amount _CH is set, and the vertical distortion correction amount _CV is set according to the vertical direction adjustment signal (step S12).

  Next, the adjustment instruction unit 110 analyzes the spatial frequency of the input image signal. Based on this analysis result, a coefficient for adjusting the image distortion correction amount is calculated (step S130).

The calculation of the coefficient in step S130 is performed for each of the horizontal direction and the vertical direction. Specifically, the horizontal image correlation coefficient HPF _H for adjusting the horizontal image distortion correction amount C _H is obtained by subjecting the image signal to a pixel adjacent to the left and right of the pixel of interest by performing a horizontal high-pass filter process on the image signal. It is calculated | required by calculating the absolute value of the difference of this signal value. In addition, the vertical image correlation coefficient HPF _V for adjusting the vertical image distortion correction amount CV is obtained by performing a vertical high-pass filter process on the image signal, so that the signal value between the pixel of interest and the pixels adjacent to the pixel of interest above and below It is obtained by calculating the absolute value of the difference.

  FIG. 17 is a diagram illustrating a configuration example of a high-pass filter (HPF). Referring to FIG. 17A, the high-pass filter is a 3 × 3 spatial filter that requires signal values of three pixels in the horizontal direction and the vertical direction. The central element of this filter corresponds to the target pixel of the image signal. In the figure, the signal value of the pixel of interest whose position is specified by coordinates (i, j) is assumed to be f (i, j).

  In FIG. 17B, as the characteristics of the high-pass filter, a filter coefficient (hereinafter also referred to as “horizontal HPF coefficient”) multiplied by the signal value of the target pixel and the pixels adjacent to the left and right of the target pixel, and the target pixel. In addition, a filter coefficient (hereinafter also referred to as “vertical HPF coefficient”) to be multiplied by the signal values of pixels adjacent above and below the target pixel is set.

In the horizontal high-pass filter process, the absolute value of the difference between the signal values of the pixel of interest and the pixels adjacent to the left and right of the pixel of interest is calculated by Expression (3) using the horizontal HPF coefficient. The absolute value of the calculated difference is set to the horizontal image correlation coefficient HPF _H.

Similarly, in the vertical high-pass filter process, the absolute value of the difference between the signal values of the pixel of interest and the adjacent pixels above and below the pixel of interest is calculated by Expression (4) using the vertical HPF coefficient. The calculated difference is set to the vertical image correlation coefficient HPF _V.

Referring to FIG. 16 again, the adjustment instruction unit 110 multiplies the calculated horizontal image correlation coefficient HPF _H by the horizontal distortion correction amount C _H set in step S12, thereby obtaining the horizontal distortion correction amount C _H. adjust. The adjustment instruction unit 110, the calculated vertical image correlation coefficient HPF _V, by multiplying the vertical distortion correction amount C _V set in step S12, adjusting the vertical distortion correction values C _V. Then, the adjustment instruction unit 110 compares the adjusted horizontal distortion correction amount (C _H × HPF _H ) with the vertical distortion correction amount (C _V × HPF _V ) (step S131).

When the adjusted horizontal distortion correction amount C _H × HPF _H is larger than the adjusted vertical distortion correction amount C _V × HPF _V (YES in step S131), the adjustment instruction unit 110 is set in step S12. and it outputs the horizontal distortion correction amount C _H to the projection device driving section 155. This instructs the projection element driving unit 155 to control the amplitude of the projection element 154 in the horizontal direction (H direction) (step S14).

Projection device driving section 155 in accordance with the horizontal distortion correction amount C _H input to set the oscillation angle of the mirror provided in the projection device 154. Specifically, the projection element driving unit 155 sets the amplitude component of the horizontal drive signal of the projection element 154 according to the horizontal distortion correction amount C _H (step S15).

In addition, the adjustment instruction unit 110 transmits the vertical distortion correction amount _CV set in step S12 to the image processing unit 151 (step S16). The image processing unit 151 thins out pixel values from the image data supplied from the image supply unit 200 in accordance with the vertical distortion correction amount _CV , so that the image forming region is vertical as it goes in the vertical direction (horizontal direction). Signal correction is performed to reduce the width in the direction (step S17).

  When receiving the vertical drive signal and the horizontal drive signal from the image processing unit 151, the projection element driving unit 155 drives the projection element 154 in the vertical and horizontal directions based on these drive signals (step S18). At this time, the swing angle of the projection element 154 in the horizontal direction is controlled to change according to the amplitude component of the horizontal drive signal of the projection element 154 set in step S15.

Returning to step S131 again, if the adjusted horizontal distortion correction amount C _H × HPF _H is equal to or less than the adjusted vertical distortion correction amount C _V × HPF _V (NO in step S131), the adjustment instruction unit 110 Outputs the vertical distortion correction amount _CV set in step S12 to the projection element driving unit 155. This instructs the projection element driving unit 155 to control the amplitude of the projection element 154 in the vertical direction (V direction) (step S19).

The projection element driving unit 155 sets the swing angle of the mirror provided in the projection element 154 according to the input vertical distortion correction amount _CV . Specifically, the projection element driving unit 155 sets the amplitude component of the vertical drive signal of the projection element 154 according to the vertical distortion correction amount _CV (step S20).

The adjustment instruction unit 110 transmits the horizontal distortion correction amount _{C H} set in step S12 to the image processing unit 151 (step S21). The image processing unit 151, in response to the horizontal distortion correction amount C _H, by performing the decimation of the pixel values from the image data supplied from the image supply unit 200, as directed toward the image forming region tilt (vertical) horizontal Signal correction is performed to reduce the width in the direction (step S22).

  When receiving the vertical drive signal and the horizontal drive signal from the image processing unit 151, the projection element driving unit 155 drives the projection element 154 in the vertical and horizontal directions based on these drive signals (step S18).

  As described above, according to the fourth embodiment of the present invention, the horizontal distortion correction amount considering the horizontal spatial frequency of the image signal and the vertical distortion considering the vertical spatial frequency of the image signal. The correction amount is compared, and the amplitude control and signal correction of the projection element 154 are properly used according to the comparison result. That is, since the spatial frequency of the image signal is considered in the image distortion correction, it is possible to suppress deterioration in image quality caused by thinning out pixel values in a direction in which the spatial frequency is larger. As a result, it is possible to realize image distortion correction for correcting an image to be displayed into a desired shape without impairing the sharpness of the image.

[Embodiment 5]
In the image distortion correction processing according to the first to fourth embodiments described above, the user adjusts the horizontal direction adjustment tool 112 (operation buttons 112L and 112R) and the vertical direction adjustment tool 113 (operation buttons 113U and 113U received by the remote controller 120). 113D) is operated (pressed) according to the horizontal image distortion correction amount and the vertical image distortion correction amount set while viewing the projection image displayed on the projection screen SC.

When correcting the image distortion, as shown in FIG. 18, if each of the horizontal and vertical directions on the projection image 300 auxiliary lines L _H, a configuration of displaying the L _V, degree of distortion users images Since it becomes easy to visually recognize, operability can be improved.

The display of the auxiliary lines L _H and L _V is executed in response to the user switching the operation mode of the projector PJ from the normal display mode to the correction mode for correcting image distortion, for example. Shall. When in the image distortion correction process is completed the operation mode of the projector PJ is switched from the correction mode to the normal display mode, the auxiliary line L _H, display of L _V is terminated.

In the first to fourth embodiments described above, the horizontal direction adjustment tool 112 and the vertical direction adjustment tool 113 are provided in the remote controller 120, but may be provided in the input operation unit of the projector PJ. Even in such a configuration, it is possible to display the auxiliary lines L _H, L _V on the projected image 300 in response to an operation of the input operation unit.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  DESCRIPTION OF SYMBOLS 100 Image display part, 110 Adjustment instruction | indication part, 112 Horizontal direction adjustment tool, 112R, 112L Operation button, 113 Vertical direction adjustment tool, 113U, 113D Operation button, 120 Remote control, 151 Image processing part, 152 Solid state light source, 153 Solid state light source drive Part, 154 projection element drive part, 155 projection element, 200 image supply part, 251 frame memory, 252 driver, 253 display part, 300 projected image, 400 scanned image, PJ projector, SC projection plane.

Claims (6)

A solid light source;
A projection element configured to vibrate in a horizontal direction and a vertical direction, and projecting an image on a projection plane by scanning the emitted light from the solid-state light source along a scanning direction;
An image distortion correction unit for correcting image distortion occurring in at least one of the horizontal direction and the vertical direction,
The image distortion correction unit
An adjustment instruction unit that sets a correction amount of image distortion in the horizontal direction and the vertical direction according to an adjustment signal for adjusting an image projected on the projection surface;
Projection that changes the scanning direction of the projection element and controls the scanning width of the projection element in the scanning direction according to the correction amount of the image distortion in the horizontal direction and the vertical direction set by the adjustment instruction unit. A projection display apparatus, comprising: an element driving unit. The projection display apparatus according to claim 1,
The image distortion correction unit further includes an image signal correction unit that reduces an image to be scanned by the projection element in a direction of image distortion by thinning out a pixel value from an image input signal.
The adjustment instruction unit compares the correction amount of the image distortion in the horizontal direction with the correction amount of the image distortion in the vertical direction,
The projection element driving unit changes the image distortion direction corresponding to the relatively large correction amount to the scanning direction based on the comparison result of the adjustment instruction unit, and according to the relatively large correction amount. Controlling the scanning width of the projection element in the scanning direction;
The image signal correction unit reduces the image to be scanned by the projection element in a direction of image distortion corresponding to a relatively small correction amount based on a comparison result of the adjustment instruction unit. Type image display device. The projection display apparatus according to claim 2,
The image distortion correction unit further includes a signal analysis unit that analyzes a signal value for each pixel in the image input signal by using a relative inclination between the projection element and the projection plane,
The adjustment instruction unit includes a correction amount of the image distortion in the horizontal direction in consideration of a signal analysis result using the relative inclination in the horizontal direction, and a signal analysis using the relative inclination in the vertical direction. A projection type image display apparatus, characterized in that a comparison is made with the correction amount of the image distortion in the vertical direction in consideration of the result. The projection display apparatus according to claim 2,
The image distortion correction unit
A frequency analysis unit for analyzing a horizontal spatial frequency and a vertical spatial frequency from a signal value for each pixel in the image input signal;
The adjustment instruction unit compares the horizontal image distortion correction amount in consideration of the horizontal spatial frequency with the vertical image distortion correction amount in consideration of the vertical spatial frequency. A projection-type image display device that is characterized. A projection display apparatus according to any one of claims 1 to 4, wherein
The adjustment signal is a signal input to the image distortion correction unit from an adjustment tool used for image distortion correction,
The projection display apparatus, wherein the image distortion correction unit further includes a display unit that displays an auxiliary line for assisting an adjustment operation in the adjustment tool on the projection plane. An image distortion correction method for a projection display apparatus for correcting image distortion occurring in at least one of a horizontal direction and a vertical direction,
The projection display apparatus is
A solid light source;
A projection element configured to vibrate in a horizontal direction and a vertical direction, and projecting an image on the projection plane by scanning light emitted from the solid-state light source along a scanning direction;
The image distortion correction method includes:
Setting horizontal and vertical image distortion correction amounts in accordance with an adjustment signal for adjusting an image projected on the projection surface;
Changing the scanning direction of the projection element according to the horizontal and vertical image distortion correction amounts set in the setting step, and controlling the scanning width of the projection element in the scanning direction; An image distortion correction method comprising:

Images