JP5206081B2 - Projector, program and storage medium - Google Patents

Description

  The present invention relates to a projector, a program, and a storage medium that perform image distortion correction.

A projector that corrects distortion of a projected image projected on a projection surface is known. The distortion of the projected image occurs when the projection direction of the projector is oblique with respect to the projection plane. If the projection direction is tilted in the vertical direction (vertical direction) with respect to the projection surface, vertical trapezoidal distortion correction is required. If the projection direction is tilted laterally with respect to the projection surface, Directional trapezoidal distortion correction is required. There are trapezoidal distortion corrections in which the user manually adjusts the correction amount and those in which the correction amount is automatically calculated using various sensors.

For example, in Patent Document 1, when a screen as a projection surface is projected without being directly facing the projector, the position of the screen with respect to the projected image display range is detected using an image sensor, and the projected image is aligned with the screen. A method for automatically correcting image distortion is described. Japanese Patent Application Laid-Open No. 2004-228620 projects four vertical one-dimensional array image pickup devices in which test patterns are projected onto a screen from four light emitting devices arranged in a line in the horizontal direction, and each reflected light is arranged in the horizontal direction. , Confirm the linearity of the four light receiving positions, find the distance from the two positions outside the light receiving position where the linearity is maintained to the screen, and automatically calculate the tilt angle of the screen A method is described.
Thus, the projection image distortion correction in recent projectors can be executed by automatically calculating the correction amount.

JP 2004-260785 A JP 2005-150919 A

By the way, although the above-mentioned Patent Document 1 and Patent Document 2 do not describe a trigger for starting the projection image distortion correction, the projection image distortion correction is started by pressing the distortion correction button, or the output of various sensors. It can also be configured to start the projection image distortion correction in response to the change.
Usually, the output value of the sensor is used for calculating the correction amount, and the value must be accurate. For this reason, the sensor mounted on the projector for correcting the projected image distortion needs to incorporate a relatively high accuracy sensor.

However, since a high-precision sensor has good sensitivity, it detects minute output changes. For this reason, if only the output change of the sensor is used as a trigger for starting the projection image distortion correction, the projection image distortion correction process is performed even when the projector is slightly moved and a projection image distortion that cannot be confirmed by human eyes occurs. Will start. It is known that the projected image distortion correction processing usually takes several seconds. For this reason, it is troublesome for the user to frequently execute the projection image distortion correction processing.

The present invention has been made to solve the above problems, and provides a projector capable of setting a trigger for starting projection image distortion correction at an appropriate timing, a program, and a storage medium storing the program The purpose is to do.

The present invention capable of solving the above problems is a projector for projecting an image,
Imaging means; detection means for detecting movement of the projector; storage means for storing image data captured by the imaging means; image data stored in the storage means; and detection means detecting movement And determining means for determining whether or not to perform projection image distortion correction based on image data captured later.

In addition, a program of the present invention that can solve the above problems includes a detection step of detecting the movement of the projector, a storage step of storing image data captured by the imaging means,
A determination step for determining whether or not to perform projection image distortion correction based on the image data stored in the storage step and the image data captured after detecting a motion in the detection step; The computer is executed.
The present invention that can solve the above-described problems is a computer-readable storage medium in which the above-described program is recorded.

According to the above configuration, the motion of the projector is detected, and it is determined whether or not to perform the projection image distortion correction based on the image data captured after the motion is detected and the stored image data. In other words, the projection image distortion correction is not performed only by detecting the movement of the projector, and the projection image distortion correction can be performed if there is a difference between the image data before and after the projector moves. Therefore, it is possible to set a trigger for starting projection image distortion correction at an appropriate timing.

In the projector according to the aspect of the invention, the storage unit may store a part of the image data or the compressed image data.
According to the above configuration, part of the captured image data is stored, or all of the image data is compressed and stored, so that the storage capacity of the storage element can be saved. Further, in the case of performing determination based on image data, it is possible to realize speeding up of the determination process by setting only a part as an object of the determination material.

In the projector according to the aspect of the invention, the determination unit may project the projection when the difference between the image data stored in the storage unit and the image data captured after the detection unit detects a motion is greater than or equal to a threshold value. Image distortion correction is executed.
According to the above configuration, the projection image distortion correction is performed only when the difference is equal to or greater than the threshold value. For example, difference data between image data stored in the storage means and image data captured after motion detection is taken, and projection image distortion correction is performed only when the difference data is greater than or equal to a threshold value. For this reason, the projector can be configured not to execute the projection image distortion correction if the projector image moves slightly and the projection image distortion is invisible to human eyes.

In the projector according to the aspect of the invention, the detection unit may detect a horizontal movement of the projector with respect to a projection plane.
According to the above configuration, the trigger for starting the horizontal projection image distortion correction with respect to the projection plane can be set at an appropriate timing. Further, it is only necessary to be able to detect movement in the horizontal direction with respect to the projection plane, and it is not necessary to detect the amount of movement, so that high-precision detection means is not required. For this reason, the cost increase of the projector can be prevented.

In the projector according to the aspect of the invention, when a moving image is being projected, the imaging unit captures a projected image obtained by projecting a specific image inserted in the moving image.
When the motion of the projector is detected during the projection of the moving image, the image data before detecting the motion and the image data after the detection are always different image data. In other words, trapezoidal distortion correction is always performed during the projection of moving images. According to the above configuration, when the image is being projected, since the projection image obtained by projecting the specific image inserted in the moving image is captured, the imaging target is always the specific image. Since the same imaging object is imaged before and after detecting the motion, it is possible to correctly determine whether or not the projector has actually moved to the extent that the projection image distortion correction is required. Therefore, it is possible to prevent the projection image distortion correction process from being executed at an unnecessary timing.

Hereinafter, a projector according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a control block diagram showing the internal configuration of the projector according to the present embodiment.
In the following, a so-called liquid crystal projector is described as an embodiment in which light is transmitted through a liquid crystal light valve and light modulated in accordance with a video signal by the liquid crystal light valve is projected onto a screen. This does not exclude projectors that employ this method.
For example, the present invention can be applied to a projector using a micromirror array device.

(Internal configuration of projector)
The projector 1 according to this embodiment mainly includes a video input unit 2, a video processing unit 3, and a video projection unit 4.
, A projected image distortion correction unit 8, a CPU 6, a memory controller 7, a captured image memory 5, a program ROM 9, a camera 10, and a motion detection sensor 11. The projection light processed by the image projection unit 4 and enlarged by the projection lens L is projected as a projection image on a projection surface such as a screen.

The image projection unit 4 includes an optical system such as a lens (not shown). Specifically, at least 2
It has a single dichroic mirror. The first dichroic mirror separates the light beam including the R (red) light component and the light beam including the G (green) light component and the B (blue) light component, and then the second dichroic mirror. Thus, the G (green) light component and the B (blue) light component are separated from the light flux including the G (green) light component and the B (blue) light component. In this way, light emitted from a light source (not shown) can be separated into three components of RGB.

The image forming unit 4a is a spatial modulation element, and includes three liquid crystal light valves provided corresponding to RGB light components. Each liquid crystal light valve is composed of a plurality of pixels arranged vertically and horizontally. The light components separated into RGB by the two dichroic mirrors are transmitted or reflected on the image written in these pixels.
The focus adjustment unit 4b performs focus adjustment of the optical system according to the distance to the projection surface based on an instruction from the CPU 6.

The image projection unit 4 includes a prism that combines light transmitted or reflected by each liquid crystal light valve, and combines the transmitted light or reflected light from the liquid crystal light valve via the prism,
The light is emitted as projection light X through the projection lens L.

The video input unit 2 inputs a video output signal or a video signal from a personal computer,
Output to the video processing unit 3.
The video processing unit 3 performs signal processing on the input video signal. That is, when the video signal input from the video input unit 2 is an analog signal, it is converted into a predetermined digital signal format by performing an analog / digital conversion process, and a video display state (for example, luminance, contrast, synchronization, tracking) , Color density, hue, etc.) are adjusted, and an image frame to be written in the image forming unit 4a is generated. The generated image frame is written to each of the RGB liquid crystal light valves.
As described above, when light is supplied from the light source to the image forming unit 4a, each light component of RGB is
Modulation is performed according to the image frame displayed on each liquid crystal light valve. In other words, the transmitted light or reflected light modulated by the image forming unit 4 a is synthesized from the video projection unit 4 and output as projection light X through the projection lens L.

In addition, the video processing unit 3 of the present embodiment generates difference data based on the image data captured by the camera 10 and the image data stored in the captured image memory 5.

The CPU 6 performs overall control of the projection process. In particular, in the present embodiment, based on the difference data generated by the video processing unit 3, it is determined whether or not the difference is greater than or equal to a threshold. If it is determined that the difference is greater than or equal to the threshold, the projected image distortion correction unit 8 Perform distortion correction. That is, the CPU 6 and the video processing unit 3 constitute a determination unit.
When the CPU 6 of this embodiment determines that the projector 1 is projecting a moving image,
The video processing 3 is instructed to periodically insert at least one frame of a specific image in the moving image, and an imaging instruction is issued to the camera 10 to capture a projection image obtained by projecting the inserted one frame. .

The motion detection sensor 11 is a gyro sensor, for example, and detects the horizontal motion of the projector 1 with respect to the projection plane. When the projector 1 moves in the horizontal direction with respect to the projection surface, an output signal is sent to the CPU 6. The CPU 6 determines that the projector 1 has moved in the horizontal direction based on the output signal. After determining that the projector has moved, if there is no output signal from the motion detection sensor 11 for a predetermined time, it is determined that the projector 1 has stopped. (Details will be described later) That is, the CPU 6 and the motion detection sensor 3 constitute a detection means.

The camera 10 captures an image based on an imaging instruction from the CPU 6. That is, the CPU 6 and the camera 10 constitute an imaging unit.
The captured image memory 5 is a storage element that stores image data captured by the camera 10. The memory controller 7 reads and writes image data in the captured image memory 5. That is, the memory controller 7 and the captured image memory 5 constitute storage means. The captured image data may be compressed and stored in the captured image memory 5.

The program ROM 9 is a storage element that stores various programs. In the present embodiment, various programs are executed and the program and the CPU 6 cooperate to form the above-described determination means, detection means, imaging means, and storage means.

(Projector motion detection processing)
Next, the projector motion detection process described above will be described in detail. FIG. 2 is a flowchart for explaining the motion detection process of the projector, and FIG. 3 is a diagram schematically showing a generation image of difference data.
A motion detection process when the projector 1 is not executing the projection process will be described.

The user turns on the power of the projector 1. When the power is turned on, the CPU 6 determines whether the lamp is lit (step S11). When it is determined that the lamp is lit (step S11: Yes), the CPU 6 instructs the camera 10 to take an image. Camera 10 that has received an imaging instruction
Images an imaging target (step S12). Here, what is to be imaged is not particularly limited. It may be a wall surface or a screen as long as it can be used for generating difference data described later. It should be noted that when only a blank white wall is imaged, it cannot be used to generate difference data.

The captured image data is stored in the captured image memory 5 by the memory controller 7 via the video processing unit 3 (step S13). Next, the image distortion correction unit 8 performs first image distortion correction after the power is turned on (step S14). The image distortion correction executed here is a correction performed uniformly regardless of whether the projector 1 has moved.

Next, when receiving an output signal from the motion detection sensor 11, the CPU 6 determines that the projector 1 has moved in the horizontal direction (step S15: Yes), and whether there is an output signal from the motion detection sensor again after a predetermined time has elapsed. It detects (step S16: Yes). Motion detection sensor 11
If there is no output signal from, it is determined that the movement has stopped (step S17: Yes). If it is determined that the movement has stopped, the CPU 6 instructs the camera 10 to capture an image again, and the camera 10 that has received the imaging instruction captures an image of the imaging target (step S18).

Next, the video processing unit 3 generates difference data between the image data stored in the captured image memory 5 in step S13 and the image data captured in step S18 (step S19).
).

FIG. 3 shows (a) image data stored in the photographed image memory 5 and (b) image data captured after detecting a motion. The difference data is, for example, the area of the image shift,
The area of (a) and (b) where there is no overlap, specifically, the area of the hatched part of (c) indicates the difference data A. The CPU 6 determines whether or not the difference data is greater than or equal to a predetermined threshold value. For example, when the area of the hatched portion is ¼ or more of the entire area (step S20: Y
es), the projector 1 recognizes that it has been moved to the extent that image distortion correction is necessary. Then, after updating the image data stored in the captured image memory 5 to the image data captured in step S18 (step S21), the image distortion correction unit 8 performs the second image distortion correction (step S14). . Thereafter, by repeatedly executing Steps S14 to S21, the second image distortion correction is executed when the projector 1 is moved to the extent that the image distortion correction is necessary.

Note that the CPU 6 may be configured to instruct the focus adjustment unit 4b to execute focus adjustment after the image distortion correction is completed.

Next, with reference to FIG. 4, the motion detection process performed by the projector 1 during the execution of the moving image projection process will be described. FIG. 4 is a flowchart for explaining the motion detection process performed by the projector 1 during the execution of the moving image projection process.
During projection of a moving image, according to the flow shown in FIG. 2, image data captured by the camera is always different data, and there is a possibility that trapezoidal distortion correction is frequently performed assuming that the difference data is always equal to or greater than the threshold value. Therefore, in the flow described below, a specific image is periodically inserted into the moving image by one frame.

The CPU 6 instructs the video processing unit 3 to insert one frame of a specific image during projection processing (step S31), and instructs the camera 10 to take an image at the timing of inserting one frame. The video processing unit 3 applies a specific image 1 in accordance with an instruction from the CPU 6.
A frame is inserted (step S32). Upon receiving the imaging instruction, the camera 10 captures an imaging target (step S33). Here, what is to be imaged is a projection image of the inserted specific image, as long as it can be used for generating difference data. For example, the specific image may be a black frame or a white frame.

The captured image data is stored in the captured image memory 5 by the memory controller 7 via the video processing unit 3 (step S34). When receiving the output signal from the motion detection sensor 11, the CPU 6 determines that the projector 1 has moved in the horizontal direction (step S35: Yes).
Then, after the predetermined time has elapsed, it is detected again whether there is an output signal from the motion detection sensor (step S36).
: Yes). If there is no output signal from the motion detection sensor 11, it is determined that the motion has stopped (
Step S37: Yes). If it is determined that the movement has stopped, the CPU 6 instructs the camera 10 to take an image at the timing when one frame is inserted.

The video processing unit 3 inserts one frame of the same specific image as the image inserted in step S32 (step S38), and the camera 10 receiving the imaging instruction images the imaging target (step S).
39). Next, the video processing unit 3 generates difference data between the image data stored in the captured image memory 5 in step S34 and the image data captured in step S39 (step S40).

The CPU 6 determines whether or not the difference data is greater than or equal to a predetermined threshold (Step S4).
1). If it is determined that the value is greater than or equal to the threshold (step S41: Yes), the image distortion correction unit 8 performs second image distortion correction (step S42). Then, after updating the image data stored in the captured image memory 5 to the image data captured in step S39 (step S43).
Thereafter, by repeatedly executing Steps S35 to S43, the second image distortion correction is executed when the projector 1 is moved to the extent that the image distortion correction is necessary.

Note that a specific image may be inserted periodically, or one frame may be inserted only when motion is detected. Also, one frame may be actually inserted only when it is inserted for the first time in step S32 out of the periodic insertion timing and only after the movement of the projector has stopped. At other timings, insertion can be omitted. This can minimize the insertion of other image frames that are not related to the actual moving image data.

Note that the CPU 6 may be configured to instruct the focus adjustment unit 4b to execute focus adjustment after the image distortion correction is completed.

Thus, according to the present embodiment, image distortion correction is not performed only by detecting the movement of the projector 1, and if the difference data of the image data before and after the projector 1 moves is equal to or greater than the threshold value,
It can be configured to perform image distortion correction. Therefore, it is possible to set a trigger for starting image distortion correction at an appropriate timing.
In the present embodiment, it is determined whether or not the difference data is greater than or equal to the threshold value. However, if there is a difference, image distortion correction may be performed.
In the present embodiment, the difference data is generated. However, the present invention is not limited to this. Other methods can be adopted as long as the difference between the image data captured after detecting the motion and the stored image data can be determined. For example, the difference may be determined by comparing only one part of the image data. In this case, speeding up of the determination process can be realized by using only a part of the target as the determination material.

In the present embodiment, the entire captured image data is stored in the captured image memory 5, but a part of the image data may be stored.

Further, according to the present embodiment, the motion detection sensor 11 detects the horizontal motion of the projector 1 with respect to the projection plane. Therefore, a trigger for starting horizontal image distortion correction can be set at an appropriate timing. Moreover, it is only necessary to be able to detect the movement in the horizontal direction, and since it is not necessary to detect the amount of movement, a highly accurate sensor is not required. For this reason, the cost increase of the projector 1 can be prevented.

Further, according to the present embodiment, in the case of a moving image, a specific image inserted in the moving image is projected,
The specific image is captured. Therefore, since the same imaging target is imaged before and after detecting the motion, it is possible to correctly determine whether the projector 1 has actually moved to an extent that requires image distortion correction. Therefore, it is possible to prevent the image distortion correction process from being executed at unnecessary timing.

Further, according to the present embodiment, image distortion correction is performed only when the difference is greater than or equal to the threshold value. For this reason, if the projector 1 moves slightly and the image distortion is such that it cannot be confirmed by human eyes, the image distortion correction can be prevented from being executed.

The camera may be fixed to the projector 1 and may not be integrated. Furthermore, the camera does not need to be installed in the same direction as the projection plane, and may be installed so as to face the rear, left, right, upper, etc. of the projector 1. In this case, the flow shown in FIG.

It is a control block diagram which shows the internal structure of the projector of this embodiment. It is a flowchart for demonstrating the motion detection process of a projector. It is the figure which showed typically the production | generation image of difference data. It is a flowchart for demonstrating the motion detection process which a projector performs during execution of the projection process of a moving image.

Explanation of symbols

1: projector, 2: video input unit, 3: video processing unit, 4 video projection unit, 5: captured image memory, 6: CPU, 7: memory controller, 8: image distortion correction unit, 9: program ROM
10: Camera, 11: Motion detection sensor

Claims (7)

In projectors that project images,
Imaging means;
Detecting means for detecting movement of the projector;
Storage means for storing image data captured by the imaging means;
Determining means for determining whether or not to perform projection image distortion correction based on image data stored in the storage means and image data picked up after the detection means detects a motion. Characteristic projector. The projector according to claim 1, wherein the storage unit stores a part of the image data or the compressed image data. The determination unit causes the projection image distortion correction to be executed when a difference between image data stored in the storage unit and image data captured after the detection unit detects a motion is equal to or greater than a threshold value. The projector according to claim 1 or 2, characterized in that The projector according to claim 1, wherein the detection unit detects a horizontal movement of the projector with respect to a projection plane. 5. The projector according to claim 1, wherein, when a moving image is being projected, the imaging unit images a projected image obtained by projecting a specific image inserted into the moving image. A detection step for detecting the movement of the projector;
A storage step for storing image data captured by the imaging means;
A determination step for determining whether or not to perform projection image distortion correction based on the image data stored in the storage step and the image data captured after detecting a motion in the detection step; A program characterized by being executed by a computer.   A computer-readable storage medium on which the program according to claim 6 is recorded.

Images