JP2019133190A - Image projection device - Google Patents

Abstract

To prevent the blur of a projection image by correcting the curvature of an image surface on a projection surface, in an image projection device.SOLUTION: The image projection device includes a shape variable mirror comprising a plurality of micro mirrors, an optical system for forming the intermediate image of an image by image data outputted from an image output part on the shape variable mirror, an imaging apparatus, an image comparison part, and a control part for controlling the shape variable mirror. The image comparison part compares and computes the image data outputted from the image output part and the imaging data of the projection surface imaged by the imaging apparatus, to acquire the blur correction amount of the image on the projection surface for each divided area of the projection image. The control part moves the micro mirrors corresponding to the respective areas according to the blur correction amount on the basis of the blur correction amount of the image on the projection surface acquired for each area.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image projection apparatus, and more particularly to an image projection apparatus suitable for correcting a blur of a projection image on a projection surface to obtain a clear projection image.

  An image projection device (projector) is a device that displays an image or video by projecting it onto a large screen or the like. In an image projection apparatus, when projecting a projection image on a projection surface, it is required to project with high accuracy in focus.

  As a technique related to the adjustment of the focal range of the image projection apparatus, for example, the technique described in Patent Document 1 is known. In Patent Document 1, a phase modulation element (Imaging Lens With EDF 332) that modulates the phase of a light beam is arranged in the projection optical system, and the point along the optical axis direction is within a certain distance from the focus plane. The function of making the image change smaller than the state without the phase modulation element is given, and image processing to cancel the amount of modulation by the phase modulation element is performed in advance on the projected image (Image Coder 314). A technique for expanding the focusing range more than usual is disclosed.

US Pat. No. 6,069,738

  In a short projection type image projection apparatus whose number of production has been increasing in recent years, the configuration of the optical system is complicated, and high level adjustment technology is required at the time of production to make the image plane of the projected image flat. This is because when the curvature of the image plane occurs due to the adjustment error, the projection image is partially blurred on the projection plane.

  Further, in the image projection apparatus, in order to focus the projection image, it is necessary to appropriately set the distance between the image projection apparatus and the projection surface. The accuracy of setting the distance becomes more severe as the projection distance becomes smaller if the aperture diameter of the projection optical system is constant, so that the setting difficulty is particularly high in the short projection type image projection apparatus. Furthermore, when the projection surface is a hanging type and is a material such as cloth, the distance between the image projection device and the projection surface may change due to the influence of wind or the like even during projection, and image blurring may occur.

  In applications such as projection mapping that projects an image onto a three-dimensionally arranged projection target, the range in the optical axis direction that can be projected without blurring the image is determined by the aperture diameter and the projection distance of the projection optical system. If the projection target is placed outside the range in the optical axis direction, the image will be blurred.

  According to the technique described in Patent Document 1, since the focus range of the projected image can be expanded in the image projecting apparatus, these problems can be solved, but the amount of modulation by the phase modulation element is added to the projected image. In order to perform image processing that cancels out in advance, contour emphasis processing is necessary, and in order to perform contour emphasis processing, it is necessary to reduce the dynamic range (tone range of the image) of the image. As a result, there is a problem that the projected image becomes an image having a small dynamic range, and the visibility becomes poor.

  The present invention has been made to solve the above problems, and its purpose is to correct the curvature of the image plane without reducing the dynamic range of the projected image, and to reduce the distance between the image projection apparatus and the projection plane. An object of the present invention is to provide an image projection apparatus that facilitates setting and can correct a variation in distance during projection. Another object of the present invention is to provide an image projection apparatus capable of enlarging the range in the optical axis direction in which a projection target can be arranged without causing blurring of an image in applications such as projection mapping.

  The configuration of the image projection apparatus according to the present invention is an image projection apparatus that projects image data output from an image output unit onto a projection surface with light emitted from a light source, and is configured to have a plurality of minute mirrors. Mirror, optical system for forming intermediate image of image based on image data output from image output unit on variable shape mirror, imaging device for imaging projection surface, image data output from image output unit and imaging device An image comparison unit that inputs imaging data of the projection surface imaged by the control unit, and a control unit that controls the deformable mirror. Then, the image comparison unit compares the image data output from the image output unit and the imaging data of the projection surface imaged by the imaging device, and the image blur correction amount on the projection surface is divided into the projection images. Based on the blur correction amount of the image on the projection surface obtained for each region, the control unit moves the micro mirror corresponding to each region according to the blur correction amount. Then, an intermediate image of the image formed on the variable shape mirror is projected.

  Preferably, in the image projection device, a cylindrical lens is disposed in the imaging device. Further, in the image projection device, the image comparison unit analyzes the image formed on the image sensor of the imaging device for each region, and based on the result of comparing the amounts of blur in two orthogonal directions in the image, The control unit is instructed to move the micromirror corresponding to each region.

  According to the present invention, the curvature of the image plane is corrected without reducing the dynamic range of the projection image, the distance between the image projection apparatus and the projection plane is easily set, and the variation in the distance is corrected even during projection. It is possible to provide an image projection apparatus that makes it possible. In addition, it is possible to provide an image projection apparatus capable of enlarging the range in the optical axis direction in which a projection target can be arranged without causing image blur in applications such as projection mapping.

It is a block diagram of the image projection apparatus of 1st embodiment which concerns on this invention. 3 is a conceptual diagram for explaining the configuration and operation of a deformable mirror 13. FIG. It is a figure for demonstrating the shape correction | amendment of an acquired image. It is explanatory drawing of the calculation method for blur amount calculation. It is a figure which shows the relationship between the shape of the transfer function of an original image and an acquisition image, and blur correction amount. 2 is a configuration diagram of an imaging device 17. FIG. It is a figure which shows the example of the relationship between a defocus and a point image at the time of setting it as the structure of the imaging device 17 of FIG. It is a figure which shows the relationship between the image surface of a projection image when an image surface curves, and a projection surface. It is a figure which shows the relationship between the image surface and projection surface of a projection image when a projection surface curves. It is a figure which shows the example of application to projection mapping. It is a block diagram of the image projection apparatus of 2nd embodiment which concerns on this invention. It is a block diagram of the image projection apparatus of 3rd embodiment which concerns on this invention. It is a figure explaining the state of the blur on image pick-up element 16 'when a focus position and the position of the projection surface 50 have shifted | deviated.

  Embodiments according to the present invention will be described below with reference to FIGS.

[Embodiment 1]
A first embodiment according to the present invention will be described below with reference to FIGS.
First, the overall configuration and operation of the image projection apparatus will be described with reference to FIGS. 1 and 2.
FIG. 1 is a configuration diagram of an image projection apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration example of the variable shape mirror.

  The image projection apparatus 100 is an apparatus that projects an image on the projection surface 50. As shown in FIG. 1, the image projection apparatus 100 includes a light source 1, an integrator lens 2, dichroic mirrors 3, 5, mirrors 4, 6, 7, liquid crystal elements 8a, 8b, 8c, dichroic prism 9, lens system 10, A polarizing prism 11, a quarter-wave plate 12, a variable shape mirror 13, a projection optical system 14, an imaging device 17, an image output unit 31, an image comparison unit 32, and a control unit 33 are provided. The imaging device 17 includes an imaging optical system 15 and an imaging element 16.

  The light source 1 emits a light beam, and the integrator lens 2 converts the light beam into parallel light. As the light source 1, for example, a metal halide lamp or an ultrahigh pressure mercury lamp is used. The dichroic mirror 3 divides the luminous flux into a red wavelength and green and blue wavelengths, transmits only the red wavelength, and reflects the green and blue wavelengths. The mirror 4 guides a light beam having a red wavelength to the liquid crystal element 8a. The dichroic mirror 5 reflects only the green wavelength of the light flux of green and blue wavelengths, guides it to the liquid crystal element 8b, and transmits the blue wavelength. The mirrors 6 and 7 guide a light beam having a blue wavelength to the liquid crystal element 8c. In this way, the liquid crystal elements 8a, 8b, and 8c receive light from the light source 1 having red, green, and blue wavelengths, respectively. The liquid crystal elements 8a, 8b, and 8c each receive a signal from the image output unit 31, and turn on / off the liquid crystal pixels in accordance with the signal. The dichroic prism 9 combines the light beams of red, green, and blue wavelengths transmitted through the liquid crystal elements into one light beam.

  Next, the lens system 10 gives a lens action to the light beam emitted from the dichroic prism 9 and guides it to the polarizing prism 11. The polarizing prism 11 has a configuration in which a linearly polarized light beam emitted from the lens system 10 is incident as S-polarized light. The S-polarized light beam is reflected and the P-polarized light beam is transmitted. The light beam is reflected and guided to the quarter-wave plate 12. The quarter-wave plate 12 converts the light beam into circularly polarized light and guides it to the shape variable mirror 13. On the reflecting surface of the deformable mirror 13, images represented by the liquid crystal elements 8a, 8b, and 8c are formed.

  The variable shape mirror 13 reflects the light beam and guides it to the quarter-wave plate 12. The quarter wavelength plate 12 converts the light flux from circularly polarized light to linearly polarized light. Since the light beam enters the polarizing prism 11 as P-polarized light, the light beam is transmitted. The projection optical system 14 gives a lens action to the luminous flux and guides it to the projection surface 50. Further, information on the focus position set in the projection optical system 14 is transmitted to the control unit 33. Images of the liquid crystal elements 8a, 8b, and 8c are formed on the projection surface 50.

  The imaging device 17 receives information on the focus position of the projection optical system 14 from the control unit 33, sets the focus position of the imaging optical system 15 to a position that matches the focus position of the projection optical system 14, and images the projection surface 50. The image information is output from the image sensor 16 and transmitted to the image comparison unit 32. The image comparison unit 32 divides the information of the original image output from the image output unit 31 and the information of the acquired image transmitted from the imaging element 16 into a plurality of regions, respectively, and performs a comparison operation for each corresponding region. The amount of blur for each region of the projected image is obtained, converted into a control amount given to each part of a micro mirror (described later) of the deformable mirror, and output. Here, the image information is digitally expressed and is information represented by RGB values for each pixel.

  The control unit 33 receives the output information output from the image comparison unit 32, and gives a control signal to the deformable mirror 13 based on the result. In the above, the conversion of the control amount given to each part of the smile mirror of the deformable mirror from the blur amount for each region of the projected image is performed by the image comparison unit, but may be performed by the control unit 33.

  The image output unit 31 outputs a digital signal input from a computer via an HDMI (registered trademark) terminal, an analog signal input via a D sub terminal, or an analog signal input from a video device via a D sub terminal to a liquid crystal element 8a, 8b and 8c.

  Calculations performed by the image comparison unit 32 and the control unit 33 are not shown in the figure, but can be realized by a program that executes the respective functions with hardware including a microprocessor and a work memory. Moreover, you may implement | achieve with the hardware circuit which performs each function.

Next, the configuration and operation of the deformable mirror 13 will be described with reference to FIG.
FIG. 2 is a conceptual diagram for explaining the configuration and operation of the deformable mirror 13. Here, FIG. 2A is an overhead view, and FIG. 2B is a side view.

  The deformable mirror (deformable mirror) is composed of a plurality of micromirrors, and can control the position of each micromirror by external control. As shown in FIG. 2A, the variable shape mirror 13 of the present embodiment is composed of a plurality of micro mirrors 130. The micromirrors 130 are, for example, coated with aluminum or gold. By controlling the voltage applied to each micromirror 130, as shown in FIG. 2B, the micromirrors 130 are shown in the optical axis direction (shown at the right end in the figure). Direction). Here, the variable shape mirror 13 is actually composed of about 32 to 4096 micromirror elements, and the amount of driving the micromirror 130 is, for example, about 5 μm.

  In the image projection apparatus according to the present embodiment, the variable shape mirror 13 receives a signal from the control unit 33 and drives the micro mirror 130 corresponding to each region of the projection image. The blur of the projected image can be corrected by setting the drive amount of the micro mirror 130 to an amount corresponding to the blur amount and setting the drive direction to a direction corresponding to the defocus direction that is the source of the blur.

Next, projection image processing of the image projection apparatus according to the embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is a diagram for explaining the shape correction of the acquired image.
FIG. 4 is an explanatory diagram of a calculation method for calculating the blur amount.
FIG. 5 is a diagram showing the relationship between the shape of the transfer function between the original image and the acquired image and the amount of blur correction.
FIG. 6 is a configuration diagram of the imaging device 17.
FIG. 7 is a diagram illustrating an example of the relationship between defocus and point images when the configuration of the imaging device 17 in FIG. 6 is used.
FIG. 8A is a diagram illustrating the relationship between the image plane of the projection image and the projection plane when the image plane is curved.
FIG. 8B is a diagram illustrating the relationship between the image plane of the projection image and the projection plane when the projection plane is curved.
FIG. 9 is a diagram illustrating an application example to projection mapping.

  First, an example of a blur amount detection method for each region of a projection image will be described with reference to FIGS. 3 and 4.

  First, as shown in FIG. 3, the image comparison unit performs geometric conversion on the projected image acquired by the imaging device 17 to perform shape correction. FIG. 3A shows the contour before correction of the acquired image, and FIG. 3B shows the contour after correction. Here, the optical axis of the imaging optical system is a direction from the back surface to the front surface of the paper. Since the optical axis is different between the projection optical system and the imaging optical system, the pixel position of the acquired image generally does not correspond to the pixel position of the original image, but this correction makes it possible to correspond and compare.

  Next, as shown in FIG. 4, the image comparison unit 32 divides the original image input from the image output unit and the acquired image in the imaging device 17 into a plurality of corresponding regions, and for each region. Fast Fourier Transform (FFT) is performed. In the figure, (a-1) shows the original image, (b-2) shows the acquired image, and (a-2) and (b-2) are enlarged views of the divided areas of the respective images. Further, (a-3) and (b-3) are graphs showing the results of the horizontal FFT of (a-2) and (b-2), respectively. In this graph, the spatial frequency is sampled from −32 to 32, and the component amount of the spatial frequency 0 is set to 1, and the relative ratio of the component amounts of the respective spatial frequencies is normalized. Then, by determining the ratio of the component amounts of the spatial frequencies represented by (a-3) and (b-3), it is determined how much image blur has occurred between the original image and the acquired image. can do. Here, FIG. 4C shows the result of taking the ratio of the component amount of the spatial frequency between the original image and the acquired image. In the figure, the broken line (a) is always 1 regardless of the spatial frequency. There is a transfer function with no blur. A solid line (A) shows a transfer function in a state where the value decreases and blur occurs at a high spatial frequency. Since the shape of the transfer function is determined according to the amount of blur, if a correspondence table between the shape of the transfer function and the amount of blur correction is prepared in advance, blur correction can be performed for each region from the shape of the transfer function by referring to the correspondence table. The amount can be determined.

  For example, as shown in FIG. 5, by integrating the graph of FIG. 4C, a region with a large value is set as a region with a low blur correction amount (level 0), and a region with a small value is a region with a large blur correction amount. (In FIG. 5, the maximum level is 4: 5 steps).

  Regarding the method of determining the defocus direction, for example, when the projection surface is flat and the shape does not change, and when it is desired to remove the curvature of the image surface by adjustment at the time of shipment or activation of the image projection device, Since high-speed correspondence is not necessarily required, the micro mirror of the deformable mirror corresponding to each region is moved in either direction, the amount of blur is calculated, and the direction in which the amount of blur is reduced is determined as the appropriate direction. It may be a method.

On the other hand, when the image projection device is being used, if the optical system is affected by heat or the like and the shape of the image plane fluctuates, or if the projection surface moves due to the influence of wind or the like, high-speed response is necessary. It is necessary to determine the defocus direction at high speed. Here, an example of a method for detecting the defocus direction of the projection image will be described with reference to FIGS. 6 and 7. A cylindrical lens 18 is arranged in the imaging optical system 15 of the imaging device 17 shown in FIG. 6A is a diagram of the imaging device 17 viewed from the direction in which the curve of the cylindrical portion of the cylindrical lens 18 can be seen, and FIG. 6B is a diagram of the same imaging device 17 viewed from a direction orthogonal thereto. . The cylindrical lens 18 has a function of changing the condensing position of the incident light beam to the imaging optical system 15 depending on the direction. In FIG. 6A, the light is collected before the image sensor 16, and in FIG. 6B, the light is collected far from the image sensor 16.
FIG. 7 shows a point image on the image sensor 16 when the cylindrical lens 18 is provided. The shape of the point image in the absence of defocus is set so as to be close to a circle as shown in FIG. Here, as shown in FIG. 6A, the length from the left to the right of the paper surface on the image pickup device 16 in the direction in which the curve of the cylindrical portion when the light is condensed before the image pickup device 16 can be seen is l and a _p, as shown in FIG. 6 (b), from the paper left on the image sensor 16 in the direction perpendicular to the direction of FIG. (a) in the case of light condensing out farther from the imaging element 16 to the right length, and _{l m.} At this time, when the defocus is negative, the shape of the point image becomes a long shape (length l _m ) from the lower left to the upper right as shown in FIG. 7A, and when the defocus is positive. The shape of the point image becomes a long shape (length l _p ) in the direction from the upper left to the lower right as shown in FIG. That is, when the defocus is negative, the shape of the blur on the image sensor from the left hand to the right hand in FIG. 6B appears in the direction from the lower left to the upper right, and the defocus is positive. In FIG. 6A, the blur shape of the length on the image sensor from the left hand to the right hand in FIG. 6A appears from the upper left to the lower right. For this reason, when calculating the blur correction amount described earlier, transfer functions are obtained in two diagonal directions, from the upper left to the lower right, and from the lower left to the upper right, and the respective transfer functions are compared. The defocus direction can be determined by examining which direction the blur amount is large.
In addition, when the projection target exists in a specific range in the optical axis direction for applications such as projection mapping, and the range is known, the focus position is set to the farthest or nearest projection position. Since the defocus directions of other projection targets are already known, it is not necessary to provide a discrimination means.

  According to this embodiment, in the image projection apparatus, when the curvature of the image plane of the projection image is generated as shown in FIG. 8A, the curvature of the image plane can be corrected. As a result, productivity at the time of production of the image projection apparatus is improved, and fluctuations in curvature of the image plane can be suppressed even if the optical system is affected by heat or the like after shipment. Further, blur due to a change in the distance between the image projection apparatus and the projection surface can be suppressed. As a result, the distance between the image projection apparatus and the projection surface can be easily set, and an image with reduced blur can be projected even if the shape of the projection surface varies due to disturbance such as wind as shown in FIG. 8B.

  Further, in an application such as projection mapping, the range in the optical axis direction in which a projection target can exist can be expanded. FIG. 9 shows an application example in the projection mapping of this embodiment. In the example shown in FIG. 9, the projection surface has two projection surfaces, a first projection surface 50-1 and a second projection surface 50-2. The second projection surface can be moved. According to this embodiment, even if the difference between the distance from the image projection device 100 to the first projection surface 50-1 and the distance from the second projection surface 50-2 is larger than the conventional one, the first An image without blur can be projected onto both the projection surface 50-1 and the second projection surface 50-2. Moreover, even if the second projection surface moves during the projection of the image, it is possible to maintain a state in which the projection image is not blurred on both the first projection surface 50-1 and the second projection surface 50-2. .

  As described above, according to the present embodiment, the curvature of the image plane of the projected image can be corrected in the image projection apparatus. As a result, adjustment of the image projection apparatus is facilitated, so that productivity at the time of production is improved, and fluctuations in the curvature of the image plane can be suppressed even if the optical system is affected by heat or the like after shipment. Further, blur due to a change in the distance between the image projection apparatus and the projection surface can be suppressed. As a result, the setting of the distance between the image projection apparatus and the projection surface becomes easy, and blurring of the image can be suppressed even if the distance between the image projection apparatus and the projection surface varies due to disturbance such as wind. Further, in an application such as projection mapping, the range in the optical axis direction in which the projection target can be arranged can be expanded without causing image blurring.

[Embodiment 2]
Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
FIG. 10 is a configuration diagram of an image projection apparatus according to the second embodiment of the present invention.

  In the present embodiment, it is assumed that the curvature of the image plane of the projected image is negligibly small or has been corrected by another means.

  In the second embodiment, as shown in FIG. 10, the image projection apparatus 101 projects an image on the projection surface 50. The image projection device 101 has the same configuration as that of the image projection device 100 in the first embodiment, except that the imaging device 17 and the image comparison unit 32 in the image projection device 100 are replaced with a distance detection unit 19. ing. In the following, differences from the first embodiment will be mainly described.

  In the present embodiment, the projection surface 50 is divided into a plurality of areas, and the distance to each area is detected by the distance detection unit 19. The distance detection unit may be a mechanism that uses an imaging device, or may be a means for transmitting light, radio waves (such as infrared rays), ultrasonic waves, etc., and receiving the light reflected by the projection surface 50. Any means can be used. In the case of using the imaging device, the distance detection unit may be a compound eye view or may be a phase difference method used for autofocus. The distance detection unit 19 outputs information on the distance to each area of the projection surface 50. The control unit 33 receives information on the focus position set in the projection optical system 14 and also receives output information from the distance detection unit 19, and based on the result of comparison between the two, outputs a control signal to the deformable mirror 13. give. The variable shape mirror 13 receives a signal from the control unit 33 and drives the micro mirror 130 corresponding to each region of the projection surface 50. The blur of the projected image can be corrected by setting the position after driving each micromirror 130 to an appropriate position corresponding to the distance to each region of the projection surface 50.

  According to this embodiment, in the image projection apparatus, blur due to a change in the distance between the image projection apparatus and the projection surface can be suppressed without detecting blur.

[Embodiment 3]
Hereinafter, a first embodiment according to the present invention will be described with reference to FIGS. 11 and 12.
FIG. 11 is a configuration diagram of an image projection apparatus according to the third embodiment of the present invention.
FIG. 12 is a diagram for explaining the state of blur on the image sensor 16 ′ when the focus position and the position of the projection surface 50 are shifted.

  Also in this embodiment, it is assumed that the curvature of the image plane of the projected image is negligibly small or has been corrected by another means.

  In the third embodiment, as shown in FIG. 11, the image projection device 102 projects an image on the projection surface 50. The image projection apparatus 102 has the same configuration as the image projection apparatus 100 in the first embodiment, but the imaging optical system 15 in the image projection apparatus 100 is omitted, and the projection optical system 14 also serves as the imaging optical system 15. The image sensor 16 is replaced by an image sensor 16 ', and the second quarter wavelength plate 20 is added. In the following, differences from the first embodiment will be mainly described.

  In the present embodiment, the second quarter-wave plate 21 converts the outgoing light beam emitted from the polarizing prism 11 and directed to the projection optical system 14 from linearly polarized light to circularly polarized light. Further, the light beam reflected by the projection surface 50 and transmitted through the projection optical system 14 is converted from circularly polarized light to linearly polarized light, and is incident on the polarizing prism as S-polarized light. The polarizing prism 11 reflects the light beam and guides it to the image sensor 16 ′. The image pickup device 16 ′ is disposed at a position conjugate with the initial position of the deformable mirror 13. When the focus position of the projection optical system 14 coincides with the projection surface 50, the image pickup device 16 ′ is in focus. The positional relationship is such that an acquired image can be acquired. In order to determine the defocus direction, when the cylindrical lens described with reference to FIG. 6 of the first embodiment is provided, it may be provided between the polarizing prism 11 and the image sensor 16 ′.

  In the present embodiment, since the state of the image acquired by the image sensor 16 ′ is different from that of the first embodiment, the state of the acquired image will be described with reference to FIG. FIG. 12 shows a state in which the projection surface 50 is shifted to the near side of the focus surface 51. In FIG. 12A, a light beam emitted from a representative point on the deformable mirror 13 and traveling toward the projection surface 50 is shown. The deformable mirror 13 is in an initial state, and light rays emitted from a point on the deformable mirror 13 and transmitted through the projection optical system 14 are collected on the focus surface 51, but cannot be condensed on the projection surface 50, and Φ1 in the figure. It becomes a circle with a diameter of the size represented by. In FIG. 12B, a light beam that is emitted from a representative point in a circle having a diameter Φ1 on the projection surface 50 and travels toward the image sensor 16 ′ is shown. The condensing position is a position farther than the image sensor 16 ′, and cannot be completely collected on the image sensor 16 ′, and becomes a circle having a diameter of Φ2 in the drawing. That is, the blur on the image pickup device 16 ′ is a blur in which the blur of the diameter Φ2 is further superimposed on the blur of the diameter Φ1.

  One of the methods for correcting the blur of the projected image in the present embodiment is a method of driving the micro mirror 130 of the deformable mirror 13 appropriately and searching for a position where the blur of each area of the acquired image by the image sensor 16 ′ is minimized. It is. That is, since the diameter of the blur on the image sensor 16 ′ that minimizes the blur of the acquired image having the above relationship is Φ2, the micromirror 130 is set so that the blur on the image sensor 16 ′ becomes Φ2. Can be adjusted so that Φ1 = 0, that is, there is no blur of the projected image.

  Another method for correcting the blur is to use the fact that the defocus amount and the blur amount on the image sensor 16 ′ have a corresponding relationship if the focus position of the projection optical system 14 is fixed. The image comparison unit 32 calculates the blur amount of each area of the acquired image on the image sensor 16 ′, and the control unit 33 acquires the blur amount information and the focus position setting information of the projection optical system 14, The defocus amount is obtained from these pieces of information, and the blur is corrected by outputting a control signal so that the micro mirror corresponding to each region is moved to the position where the defocus amount is corrected with respect to the deformable mirror 13. be able to.

  In the present embodiment, since the projection optical system and the imaging optical system are common, shape correction by geometric conversion of the acquired image as shown in FIG. 3 is unnecessary, so blurring is performed with higher accuracy than in the first embodiment. It is possible to detect, and blur due to a change in the distance between the image projection apparatus and the projection surface can be suppressed. Further, since the imaging optical system can be omitted, it can be expected that the manufacturing cost is reduced as compared with the first embodiment.

DESCRIPTION OF SYMBOLS 1 ... Light source 2 ... Integrator lens 3, 5 ... Dichroic mirror 4, 6, 7 ... Mirror 8a, 8b, 8c ... Liquid crystal element 9 ... Dichroic prism 10 ... Lens system 11 ... Polarizing prism 12, 20 ... 1/4 wavelength plate 13 ... shape variable mirror 14 ... projection optical system 15 ... imaging optical system 16 ... imaging element 17 ... imaging device 18 ... cylindrical lens 19 ... distance detection unit 31 ... image output unit 32 ... image comparison unit 33 ... control unit 50 ... projection surface 100 , 101, 102... Image projection apparatus (Embodiment 1, Embodiment 2, Embodiment 3)

Claims (5)

An image projection device for projecting an optical image based on input image data onto a projection surface,
A light source that emits light;
An optical modulator that modulates light from the light source based on the input image data to form an optical image;
A variable shape mirror composed of a plurality of micromirrors;
A first optical system for guiding an optical image formed by the light modulator on the deformable mirror;
A second optical system that projects the optical image reflected by the deformable mirror onto the projection surface;
An imaging device for imaging a projection optical image on the projection surface;
An image comparison unit that inputs the input image data and imaging data of the projection optical image captured by the imaging device;
A control unit for controlling the deformable mirror,
The image comparison unit compares the input image data with imaging data of the projection optical image captured by the imaging device, and calculates a blur correction amount of the projection optical image for each of the divided projection optical images. Seeking for each area,
The control unit moves the position of the minute mirror of the deformable mirror corresponding to each region based on the blur correction amount of the projection optical image obtained for each region, and each region An image projection apparatus characterized by individually controlling the focus corresponding to. The image projection apparatus according to claim 1, wherein a cylindrical lens is disposed in the imaging apparatus. The image comparison unit analyzes an image formed on the image sensor of the imaging device for each divided region, and based on a result of comparing blur amounts in two orthogonal directions in the image, the control unit The image projection apparatus according to claim 2, wherein an instruction of a moving direction is given to a corresponding minute mirror among the minute mirrors constituting the variable shape mirror. The image projection apparatus according to claim 1, wherein a part of the second optical system for projecting an image on the projection surface is common with a part of the imaging optical system of the imaging apparatus. An image projection device for projecting an optical image based on input image data onto a projection surface,
A light source that emits light;
An optical modulator that modulates light from the light source based on the input image data to form an optical image;
A variable shape mirror composed of a plurality of micromirrors;
A first optical system for guiding an optical image formed by the light modulator on the deformable mirror;
A second optical system that projects the optical image reflected by the deformable mirror onto the projection surface;
A distance detector for measuring the distance to the projection surface;
A control unit for controlling the deformable mirror,
The second optical system outputs information on the focus position of the second optical system to the control unit,
The distance detection unit detects the distance to each region of the projection surface for each divided region of the projection surface, and outputs the distance to the control unit,
The control unit is based on information about the focus position of the second optical system input from the second optical system and the distance to each region of the projection surface input from the distance detection unit, An image projection apparatus characterized in that the focus of each region is individually controlled by moving the position of the minute mirror of the deformable mirror corresponding to each region.

Images