JP2010273157A - Image projection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image projection device for automatically performing reversal processing of a normal projection image without needing a manual setting of a user nor depending on an installation condition, and trapezoidal distortion correction in response to a tilt angle of the image projection device. <P>SOLUTION: This image projection device includes: an acceleration detection means 1 including an acceleration sensor for measuring acceleration in a first axial direction and a second axial direction for deriving angle information related to an installation angle of the device from the measured acceleration; a video signal processing means 4 to perform reversal processing and trapezoidal distortion correction to a video signal based on the acceleration and the angle information obtained by the acceleration detection means 1; and a video output means 5 to project a video on a projection surface based on the video signal processed by the video signal processing means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image projection apparatus having an automatic inversion process of a projected image and an automatic trapezoidal distortion correction function.

  2. Description of the Related Art An image projection apparatus is known that uses a device such as a liquid crystal panel or a DMD (Digital Micromirror Device (registered trademark)) to enlarge and project an optical image onto a screen or the like.

  In addition to normal floor-standing installation, the image projection device can also be suspended from the ceiling by inverting the device upside down, so the function to display the inverted image of the projected image vertically and horizontally according to the installation method Some are equipped with.

  Normally, it is ideal to install the image projector so that the distance from the center of the projected image to the top, bottom, left, and right ends is equal by making the screen and the projection lens optical axis perpendicular to each other. A rectangular image with a ratio (4: 3, 16: 9, etc.) is projected on the screen.

  However, in an actual installation environment, the apparatus cannot be installed so as to project perpendicularly to the screen, and may be projected obliquely upward or obliquely downward. This is generally referred to as “tilting projection”, but when tilting projection is performed, the projected image is distorted into a trapezoid, and thus it is necessary to perform image processing by trapezoidal distortion correction.

  When performing reverse display or keystone correction, the user can display the menu screen by operating the keys provided on the main unit of the image projector or the infrared remote controller, and select the reverse display setting from the items, Make correction settings. However, it is a burden for the user to perform such a complicated setting operation every time the apparatus is installed.

  Therefore, in the image projection apparatus described in Patent Document 1, an acceleration sensor that is mounted so as to be inclined with respect to the optical axis of the projection lens detects the inclination angle of the apparatus, so that the projection image is automatically inverted and trapezoidal distortion correction is performed. It is carried out.

JP 2005-348242 A

  In the image projection apparatus described in Patent Document 1, by mounting an acceleration sensor that detects an angle with respect to the horizontal direction, the inclination angle (installation angle) and inclination direction of the apparatus, and the installation method (floor installation or ceiling installation) can be determined. Based on this, inversion processing and trapezoidal distortion correction are performed. However, since the acceleration sensor is pre-tilted with respect to the optical axis of the projection lens, the inversion process based on the detection result depends on the initial value of the inclination angle of the acceleration sensor, and depends on the installation state of the image projection device. May cause a malfunction such as reversal processing when installed on the floor. In addition, since the inclination direction of the image projection apparatus is determined based on the polarity of the angle detected by the sensor, the installation angle of the apparatus capable of correcting the trapezoidal distortion is limited to a range within the initial value of the inclination angle of the acceleration sensor. There is a point.

  Therefore, the present invention provides an image projection apparatus that does not require manual setting by the user and automatically performs normal image reversal processing and trapezoidal distortion correction according to the inclination angle of the image projection apparatus, regardless of the installation state. The purpose is to do.

  The image projection apparatus of the present invention includes an acceleration sensor that measures acceleration in the first axial direction and the second axial direction, and acceleration detection means that derives angle information related to the installation angle of the apparatus from the measured acceleration. Based on the acceleration and angle information obtained by the acceleration detection means, video signal processing means for performing inversion processing and trapezoidal distortion correction on the video signal, and video on the projection surface based on the video signal processed by the video signal processing means And video output means for projecting.

  The image projection apparatus of the present invention includes an acceleration sensor that measures acceleration in the first axial direction and the second axial direction, and acceleration detection means that derives angle information related to the installation angle of the apparatus from the measured acceleration. And video signal processing means for performing inversion processing and trapezoidal distortion correction on the video signal based on the acceleration and angle information obtained by the acceleration detection means. Thereby, it is possible to automatically perform the normal projection image reversal process and the trapezoidal distortion correction according to the inclination angle of the image projection apparatus without depending on the installation state without requiring manual setting by the user.

1 is a block diagram illustrating a configuration of an image projection apparatus according to a first embodiment. FIG. 3 is a diagram illustrating an installation example of the image projection apparatus according to the first embodiment. FIG. 3 is a diagram illustrating an installation example of the image projection apparatus according to the first embodiment. FIG. 3 is a diagram illustrating an installation example of the image projection apparatus according to the first embodiment. 3 is a flowchart for explaining the operation of the image projection apparatus according to the first embodiment.

(Embodiment 1)
<Configuration>
FIG. 1 is a block diagram showing the configuration of the image projection apparatus according to the first embodiment. The image projection apparatus includes acceleration detection means 1, video signal control means 2, video input means 3, video signal processing means 4, and video output means 5.

  The acceleration detection unit 1 includes an acceleration sensor that measures acceleration in two axial directions, detects angle information related to the installation angle of the image projection apparatus, and outputs the angle information to the video signal control unit 2. The video signal control unit 2 sends a control signal for performing inversion processing and trapezoidal distortion correction to the video signal processing unit 4 based on the detection result of the acceleration detection unit 1.

  A digital video signal digitally converted by the video input means 3 is input to the video signal processing means 4, and on the basis of the control signal from the video signal control means 2, change processing such as inversion processing and trapezoidal distortion correction is performed. The video output means 5 includes a projection lens (not shown), and displays the video on the internal display panel based on the digital video signal changed by the video signal processing means 4. The image displayed on the display panel is emitted as an optical image by the projection light of the light source, and the projection lens enlarges and projects it on a display surface such as a screen.

  That is, the image projection apparatus according to the present embodiment includes an acceleration sensor that measures acceleration in the first axial direction and the second axial direction, and derives angle information related to the installation angle of the apparatus from the measured acceleration. On the basis of the acceleration and angle information obtained by the acceleration detection means 1, the video signal processing means 4 for performing inversion processing and trapezoidal distortion correction on the video signal, and the video processed by the video signal processing means 4 Image output means 5 for projecting an image on the projection surface based on the signal. Thereby, it is possible to automatically perform the normal projection image reversal process and the trapezoidal distortion correction according to the inclination angle of the image projection apparatus without depending on the installation state without requiring manual setting by the user.

<Reversal processing and keystone correction>
Next, inversion processing performed by the video signal processing means 4 will be described. The video signal transmitted in time series is displayed as an image on the display panel by performing horizontal scanning from left to right and vertical scanning from top to bottom. Therefore, inversion processing is performed by inverting the driving direction of a circuit that performs horizontal scanning or vertical scanning. That is, by performing horizontal scanning from the right to the left and performing vertical scanning from the bottom to the top, an image in which the positional relationship between the top, bottom, left, and right is switched (reversed) is displayed.

  Next, the trapezoidal distortion correction performed by the video signal processing means 4 will be described. A circuit that performs trapezoidal distortion correction is configured by a computer including a CPU and a memory, and performs angle-of-view conversion according to a correction amount separately provided for a video signal. This correction amount is derived from the installation angle of the device detected by the acceleration detecting means 1.

  The inversion processing and trapezoidal distortion correction will be further described based on a specific installation example of the image projection apparatus shown in FIGS. FIG. 2 is a diagram when the image projection device is installed on the floor and projected upward at an installation angle θ with respect to the screen. FIG. 3 is a diagram where the image projection device is installed on the floor and directed downward with respect to the screen. It is a figure at the time of projecting at the installation angle θ. FIG. 4 is a diagram when the image projection apparatus is installed on a ceiling and projected at an installation angle θ upward with respect to the screen. In these drawings, the projection optical axis direction is the x axis, the vertical direction of the image projection apparatus is the y axis, the acceleration in the x axis direction detected by the acceleration sensor is A, and the acceleration in the y axis direction is B.

  The acceleration sensor of the acceleration detection means 1 is mounted so that one axis thereof is the same as the projection optical axis direction of the projection lens of the video output means 5, so that the image projection apparatus is installed in the horizontal direction with respect to the ground plane. For example, the force detected by the acceleration sensor is only the gravitational acceleration 1g acting in the vertical downward direction of the apparatus, that is, in the −y axis direction. However, when the image projection apparatus is tilted and installed as shown in FIGS. 2 and 3, the acceleration sensor detects acceleration A in the x-axis direction and acceleration B in the y-axis direction. The acceleration A and the acceleration B correspond to a decomposition component of the weight acceleration 1g.

  In order to define the upward direction of the apparatus as the positive direction of the y-axis, when the image projection apparatus is suspended from the ceiling as shown in FIG. 4, the sign of the acceleration B is reversed from the case of floor-standing installation (FIGS. 2 and 3). As shown in FIGS. 2 and 3, the acceleration B in the y-axis direction is a negative value in the floor-mounted installation, but the acceleration B is a positive value in the ceiling-mounted installation as shown in FIG. Therefore, if the acceleration B detected by the acceleration sensor is positive, the image projection apparatus determines that the top / bottom is inverted due to installation on a ceiling or the like, and the video signal processing means 4 performs a reversal process of the projected image.

  That is, the direction of the second axis is the height direction of the apparatus, and the video signal processing means 4 selectively performs the inversion process based on the sign of the acceleration B in the second axis direction. As a result, the reversing process can be automatically performed without manual setting by the user.

Further, when the projector is placed on the floor and projected upward (FIG. 2), the acceleration A becomes a positive value. However, when the projector is projected downward (FIG. 3), the acceleration A becomes a negative value. Therefore, if the acceleration A detected by the acceleration sensor is positive, the video signal processing means 4 performs upward trapezoidal distortion correction according to the installation angle θ, and if the acceleration A is negative, the video signal processing means 4 corresponds to the installation angle θ. Performs downward keystone distortion correction. The installation angle θ is calculated as θ = sin ⁻¹ | A | / g using the acceleration A detected by the acceleration sensor and the gravitational acceleration g.

  That is, the direction of the first axis is the direction of the projection optical axis of the video output means 5, and the angle information (installation angle θ) is calculated from the acceleration A and the gravitational acceleration g in the first axis direction. To do. This makes it possible to automatically perform trapezoidal distortion correction based on the tilt projection direction determined by the positive / negative acceleration A and the installation angle θ of the apparatus, regardless of the user's manual setting.

In the above description, since the y axis is perpendicular to the x axis in the vertical direction of the apparatus, the acceleration g is derived from g ² = A ² + B ² without setting the gravitational acceleration g as a known value. It is possible. However, the y-axis need not be in the direction perpendicular to the x-axis, and the direction of acceleration measured by the acceleration sensor may be two different axes as long as the above effect is obtained.

  When the device is suspended from the ceiling, the acceleration A becomes negative if projected upward (FIG. 4), and the acceleration A becomes positive if projected downward (not shown). The polarity of acceleration A is reversed with time. Therefore, if trapezoidal distortion correction is performed as in the case of floor installation, downward trapezoidal distortion correction is performed during upward tilt projection, and upward trapezoidal distortion correction is performed during downward tilt projection. However, in the case of ceiling installation based on the value of acceleration B, reverse display is performed before trapezoidal distortion correction, and the polarity of trapezoidal distortion correction is reversed when reverse display is performed. Therefore, in the case of ceiling-mounted installation, as with floor-mounted installation, upward trapezoidal distortion correction is performed when acceleration A is positive, and downward trapezoidal distortion correction is performed when acceleration A is negative, thereby following the installation situation. Appropriate trapezoidal distortion correction is made.

  FIG. 5 is a flowchart showing the process of inversion processing and trapezoidal distortion correction. Hereinafter, the operation of the video signal processing means 4 will be described with reference to FIG.

  First, the video signal processing means 4 reads the accelerations A and B detected by the acceleration sensor of the acceleration detection means 1 and the installation angle θ of the apparatus (step S1). Next, whether the acceleration B is positive or negative is determined (step S2). If the acceleration B is positive, the projection image is vertically and horizontally reversed (step S3). If negative, the process proceeds to step S4 without performing the inversion process.

  Next, the polarity of the acceleration A is determined (step S4), and if the acceleration A is positive, upward trapezoidal distortion correction according to the installation angle θ is performed (step S5). If the acceleration A is negative, downward trapezoidal distortion correction corresponding to the installation angle θ is performed (step S6). This completes the inversion processing and the trapezoidal distortion correction in the video signal processing means 4.

<Effect>
The image projection apparatus according to the present embodiment has the following effects as already described. That is, the image projection apparatus includes an acceleration sensor that measures acceleration in the first axial direction and the second axial direction, and acceleration detection means 1 that derives angle information related to the installation angle of the apparatus from the measured acceleration. Based on the acceleration and angle information obtained by the acceleration detecting means 1, the video signal processing means 4 for performing inversion processing and trapezoidal distortion correction on the video signal, and projection based on the video signal processed by the video signal processing means 4 Video output means 5 for projecting video onto the surface. Thereby, it is possible to automatically perform the normal projection image reversal process and the trapezoidal distortion correction according to the inclination angle of the image projection apparatus without depending on the installation state without requiring manual setting by the user.

  The direction of the first axis is the direction of the projection optical axis of the video output means 5, and the angle information (installation angle θ) is calculated from the acceleration A and the gravitational acceleration g in the first axis direction. To do. Thereby, it is possible to perform trapezoidal distortion correction according to the direction of tilt projection and the installation angle θ of the apparatus regardless of the manual setting by the user.

  Further, the direction of the second axis is the height direction of the apparatus, and the video signal processing means 4 selectively performs the inversion process based on the sign of the acceleration B in the second axis direction. As a result, the reversal process can be automatically performed without depending on the installation state of the image projection apparatus, regardless of the manual setting by the user.

  The present invention eliminates the need for the user to manually change the setting every time the image projection apparatus is installed, and automatically performs the trapezoidal distortion correction for the inversion processing of the projection image. This is useful when it is used in a case where it cannot be installed perpendicularly to the screen.

  1 acceleration detection means, 2 video signal control means, 3 video input means, 4 video signal processing means, 5 video output means.

Claims (3)

An acceleration detecting means including an acceleration sensor for measuring acceleration in the first axial direction and the second axial direction, and deriving angle information related to an installation angle of the apparatus from the measured acceleration;
Video signal processing means for performing inversion processing and trapezoidal distortion correction on the video signal based on the acceleration and the angle information obtained by the acceleration detection means;
An image projection apparatus comprising: a video output unit configured to project a video on a projection surface based on the video signal processed by the video signal processing unit. The direction of the first axis is the direction of the projection optical axis of the video output means,
The image projection apparatus according to claim 1, wherein the angle information is calculated from acceleration in the first axial direction and gravitational acceleration. The direction of the second axis is the height direction of the device;
The image projection apparatus according to claim 1, wherein the video signal processing unit selectively performs the inversion processing based on whether the acceleration in the second axial direction is positive or negative.

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