JP5119607B2 - projector - Google Patents

Description

  The present invention relates to a projection type projector.

Conventionally, in a projection type projector that projects an image on a screen, a wall, or the like, the image quality of the projected image is adjusted so that the user can reproduce a desired color on the screen. Further, when projecting an image onto a projection surface such as a household wall that is not a dedicated screen, a projector that detects the state of the projection surface and reduces the projected image to a projection surface size that can project the image uniformly is projected. It has been proposed (see, for example, Patent Document 1).
Japanese Patent Application Laid-Open No. 2005-109916.

  However, in the projector disclosed in Patent Document 1, since the image is projected in a reduced size so as to exclude the uneven color portion of the projection surface from the projection surface, a wide projection is required when projecting onto a household wall or the like. There is a problem that it is difficult to secure the area and the projected image becomes small.

  The present invention has been made in view of the above problems, and projects an image while reducing the influence of a nonuniform color or reflectance on the projection surface of a household wall or the like. An object of the present invention is to provide a projector that makes it possible.

In order to solve the above problems, the present invention provides:
An image projection element having a plurality of pixels forming a projection image;
A projection optical system that projects an image formed by the image projection element onto a projection surface;
An imaging unit that captures a projection image projected onto the projection plane via the projection optical system;
An image processing unit that obtains the color and brightness of each of the plurality of pixels of the projection image projected on the projection plane imaged by the imaging unit;
An image correction unit that calculates image correction information for each of the plurality of pixels for projecting a uniform image on the projection plane from a projection image captured by the imaging unit;
And an image forming control unit for correcting the projection image formed by said image projection device by said image correction information calculated by the image correcting unit,
The color and brightness for each of a plurality of pixels of the corrected projection image projected on the projection plane obtained by imaging the projection plane on which the projection image corrected by the image formation control unit is projected. When the image correction unit determines whether or not the color and the brightness are substantially constant, the image formation control unit corrects the input projection image based on the image correction information. Project onto the projection surface,
When the color and the luminance is determined not to become substantially constant, the whether the luminance is within a predetermined percentage of the maximum brightness of the projector the image correcting unit is determine a constant,
When the luminance is not within the predetermined ratio of the maximum luminance, the image formation control unit corrects the input projection image based on the image correction information and projects the input projection image on the projection plane,
When the luminance is within the predetermined ratio of the maximum luminance, the image display unit increases the luminance of light projected onto the projection plane by a predetermined amount, and is projected again onto the projection plane by the imaging unit. Shooting of a projected image, acquisition of color and brightness for each of the plurality of pixels by the image processing unit of the captured projection image, and projecting a uniform image from the projected image to the projection plane by the image correcting unit There is provided a projector characterized in that the calculation of the image correction information for correction and the correction of the projection image formed by the image projection element based on the image correction information by the image formation control unit are performed.

  According to the present invention, there is provided a projector capable of projecting an image while reducing the influence of a portion having uneven color and reflectance on a projection surface on a household wall or the like. be able to.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of a state in which an image is projected on a wall by a projector according to an embodiment of the present invention. FIG. 2 shows a schematic block diagram of the projector according to the embodiment of the present invention. FIG. 3 shows an example of the positional relationship between the pixels of the image projection element and the imaging element on the projection plane of the projector according to the embodiment of the present invention. FIG. 4 is an operation flowchart of the projector according to the embodiment of the invention.

  In FIG. 1, when an image is projected from the projector 1 onto the projection surface 2 of the wall surface 3, the environment around the projection surface 2 is often not in a dark state. For example, as shown in the figure, a floor stand 4 for securing a slight brightness in the room is provided near the wall surface 3, or a ceiling lamp (not shown) may be provided on the ceiling. . When the light of the floor stand 4 shown in the figure is lit, the left side of the projection surface 2 (left side in FIG. 1) is brighter than the right side of the projection surface 2 by the light from the floor stand 4. When an image of a movie or the like is projected from the projector 1 in this state, the image quality differs between the left side and the right side of the projection surface, and the image is unsatisfactory for the viewer of the image.

  In addition, when projecting a large screen image at home, the wall surface 3 is used, but the wall surface 3 of the home is affixed with wallpaper, and this wallpaper has a color and pattern, The surface condition is different from the projector-dedicated screen. In such a home environment, when an image is projected onto a projection surface different from the surface state of a dedicated screen, the projected image is inevitably deteriorated, and it is difficult to obtain an image with an image quality that can be appreciated. In such a case, the user tries to improve the image quality by adjusting the white balance, brightness, etc. according to the state of the projection surface to be projected.

  The projector 1 according to the embodiment of the present invention provides information such as the color of the projection surface on which the image is projected and the reflectance in order to minimize the deterioration of the image quality even in an environment where the image quality is deteriorated as described above. Obtaining and correcting the color of the projection surface to reduce the deterioration of the image quality of the projected image. Hereinafter, the projector 1 according to the embodiment of the present invention will be described in detail.

  FIG. 2 is a schematic block diagram of the projector 1 according to the embodiment of the present invention. In FIG. 2, the projector 1 uses red (R), green (G), and blue (B) (hereinafter referred to as RGB) image signals as image information input from the external input unit 10 or the memory card insertion unit 11. And an image display control unit 14 for sending to the image display unit 13 of the projector 1.

  In the image display unit 13, RGB image projection elements (for the sake of simplicity, these are respectively denoted as 13 R, 13 G, and 13 B) are modulated by signals from the image display control unit 14, and light from the light source 15 is modulated. The light is emitted from 13R, 13G, and 13B, and an image is projected onto the projection surface 2 via the projection optical system 12. As the image projection elements 13R, 13G, and 13B, a light valve using a LCD or LCOS, a micromirror array, or the like can be used. In the following description, an LCD light valve is used, but the same applies to other image projection elements.

  The projector 1 is also provided with an image sensor 16 for acquiring the color and reflectance of the surface of the projection surface 2 on which the image is projected. The projected image reflected from the projection surface 2 is imaged on the image sensor 16 via an imaging optical system (not shown) by disposing an optical path dividing unit (not shown) on the optical axis of the projection optical system 12. The optical path splitting means can be configured to be detachable from the optical axis of the projection optical system 12 and can be configured to be inserted into the optical axis of the projection optical system 12 only when necessary. As the image sensor 16, for example, an image sensor such as a CCD or a CMOS can be used. In the following description, a description will be given using a CCD, but the same applies to other imaging elements. The CCD 16 captures an image projected on the projection plane 2 via the projection optical system 12 of the projector 1. As described above, the projection optical system 12 of the projector 1 is shared, and the image display area of the image display unit 13 and the imaging area captured by the CCD 16 are configured to be equal.

  The image of the projection surface 2 captured by the CCD 16 via the projection optical system 12 is subjected to image processing for each pixel constituting the CCD 16 by the image processing unit 17 and stored as color information composed of RGB for each pixel of the projection surface 2. Stored in the unit 18. Here, the information includes each luminance information as well as each color information of RGB.

  The image control unit 19 calculates color information and reflectance information at each location of the projection image corresponding to each pixel of the CCD 16 from the information for each pixel of the CCD 16 stored in the storage unit 18. Further, from the color information for each pixel of the CCD 16, the color having the highest appearance frequency in the projection image is obtained, and the color of the projection surface 2 on which the projection image is projected is made substantially the same color as the obtained color. The color correction information is calculated, and the calculated color correction information is stored in the storage unit 18. At the same time, the corrected luminance is also calculated from the color correction information and stored in the storage unit 18 together with the color correction information. Here, the color correction information includes RGB luminance information together with RGB color correction information.

  In addition, the image control unit 19 is provided with a manual input unit 20 so that the user can arbitrarily adjust the color or brightness of the corrected projection image via the image control unit 19. It has become. The color information and luminance information after the user manually adjusts using the manual input unit 20 are stored in the storage unit 18 as manual adjustment color correction information together with the color correction information before manual adjustment. Here, the manual color correction information includes RGB brightness correction information together with RGB color correction information.

  Based on the color correction information calculated by the image control unit 19 or manually adjusted color information, the image display control unit 14 performs color correction on the RGB color information and luminance information of the input image, and transmits them to the image display unit 13. By correcting the color information and the luminance information of the input image using the color correction information, the input image, which is assumed that the color of the projection plane 2 has been corrected to substantially the same color and the same luminance, is projected onto the projection plane 2, and the projection image It becomes possible to reduce the deterioration of quality. Thus, the projector 1 according to the embodiment of the present invention is configured.

  Next, the color correction method in the projector 1 according to the embodiment of the present invention will be described in detail. The color correction method includes a luminance correction method, but since the luminance can be calculated from the color information, the following description will mainly explain the color information.

  The projector 1 according to the embodiment of the present invention is configured such that each pixel of the image projection elements 13R, 13G, and 13B that projects an image on the projection surface 2 and each pixel of the CCD 16 are associated with each other. For example, as shown in FIG. 3, when each of 13R, 13G, and 13B is composed of (m × n) pixels and the projection plane 2 is formed by this, the CCD 16 is also composed of (m × n) pixels. The positions (i, j) of the respective pixels on the projection plane 2 are associated with each other. That is, the pixels of the image projection element that projects an image at the position (i, j) on the projection plane 2 are 13R (i, j), 13G (i, j), and 13B (i, j), respectively. The projected image of i, j) is captured by the pixel at position (i, j) of the CCD 16.

  FIG. 3 shows a case where positioning on the projection plane 2 is determined such that the lower left corner of the drawing is a pixel (0, 0) and the upper right corner is a pixel (m, n). This is merely an example, and the method of determining the position of the pixel is not limited to this. When the number of pixels of the CCD 16 is larger than the number of pixels of the image projection elements 13R, 13G, and 13B, the projection light from one pixel of the image projection elements 13R, 13G, and 13B is received by a plurality of pixels of the CCD 16. What is necessary is just to comprise so that it may receive light. Further, when the number of pixels of the CCD 16 is smaller than the number of pixels of the image projection elements 13R, 13G, and 13B, one pixel of the CCD 16 is configured to cover a plurality of pixels of the image projection elements 13R, 13G, and 13B. Similar effects can be achieved.

  Next, processing relating to the color correction method of the projector 1 according to the embodiment of the present invention will be described with reference to the flowchart of FIG.

  When the user presses a projection surface color correction button (not shown) of the projector 1, the following color correction steps are executed.

(Step S1)
In order to obtain information on the color and luminance of the projection plane 2, a white image having a luminance of 50% of the maximum luminance is projected from the projector 1 onto the projection plane 2.

(Step S2)
An area where the white image is projected on the projection surface 2 is imaged by the CCD 16.

The image processing unit 17 acquires color information at each position of the projection image from the pixel signal corresponding to each position on the projection plane 2 imaged by the CCD 16 and stores it in the storage unit 18.

(Step S3)
In order to determine the color of the projection plane 2 from the acquired color information, a color histogram is obtained by calculation.

(Step S4)
Since the color having the highest appearance frequency in the color histogram is the color information having the largest number on the projection plane 2, this color is selected as a color for correcting the projection plane 2 uniformly. At the same time, luminance information is selected. In this step, when the color obtained by correcting the projection plane 2 is set to white, the user operates the selection unit (not shown) to perform color correction for changing the color of the projection plane 2 to white. be able to.

(Step S5)
The color correction information of each pixel is calculated and obtained so that (n × m) pieces of color information corresponding to the number of pixels of the CCD 16 become the color selected on the projection plane 2 in step S4. The obtained color correction information corresponding to each pixel of the CCD 16 is stored in the storage unit 18. When the setting for setting the color of the projection surface 2 to white is selected, the color correction information of each pixel is obtained by calculation so that each color information is white, and is stored in the storage unit 18 as the color correction information. Saved. In addition, luminance information is calculated from the color information and stored in the storage unit 18 together with the color information.

(Step S6)
Color correction information for each pixel of the CCD 16 is sent from the image control unit 19 to the image display control unit 14, and each of the image projection elements 13R, 13G, and 13B is used to make the projection surface 2 a selected color (or white). Pixel color correction is performed and projected onto the projection plane 2 via the projection optical system 12. The corrected projection image is picked up again by the CCD 16.

(Step S7)
The image processing unit 17 performs the same processing as the above-described step S2 on the captured image, and the color and brightness of the projection surface 2 on which the color-corrected projection image is projected from the color information for each pixel of the CCD 16 are substantially constant. Determine whether it has become. If the determination is YES, the process jumps to step S8, and if NO, the process jumps to step 10.

(Step S8)
The user decides whether to finely adjust the color and brightness of the projected image manually. If the user feels that the surface on which the projected image is projected is not uniform or the color is strange, the user can make fine adjustments. Further, when the color of the projected image is selected to be white, there is a range from reddish white (color temperature is low) to bluish white (color temperature is high), and it is necessary to match the preference of the user. For this reason, the user can manually adjust the color and brightness. If manual adjustment is not required, the process jumps to step S9, and if manual adjustment is made, the process jumps to step S12.

(Step S9)
The image control unit 19 stores the color correction information of each pixel of the CCD 16 in the storage unit 18 as the color correction information of each pixel of the image projection elements 13R, 13G, and 13B.

(Step S10)
If it is determined in step S7 that the color and brightness are not substantially constant, it is determined whether the brightness is within 80% of the maximum brightness of the projector 1.

  If the luminance exceeds 80% of the maximum luminance, further correction will cause the dynamic range of the image to be too narrow, so the process jumps to step S8 and the subsequent processing is continued. On the other hand, when the luminance is within 80% of the maximum luminance, the process jumps to step S11.

(Step S11)
The brightness of the light projected on the projection surface 2 by the image display unit 13 is increased by a predetermined amount (for example, about 5% with respect to the maximum brightness), the process jumps to step S2, and the subsequent processing is continued.

  By these steps S10 and S11, excessive correction of luminance can be prevented, and deterioration of the image quality of the projected image can be prevented.

(Step S12)
When it is desired to manually adjust the color and brightness projected on the projection plane 2 in step S8, the manual input unit 20 provided in the image control unit 19 is operated to adjust the color and brightness, and the process jumps to step S9. The subsequent processing is continued.

  With the processing from step S1 to step S12, the acquisition of the color correction information for the color state of the projection surface 2 is completed.

  When an input image is input in step S13, the color information of the input image is corrected based on the color correction information and projected from the projector 1 onto the projection plane 2.

(Step S13)
When the projector 1 projects an image, color correction information is sent from the storage unit 18 to the image display control unit 14 via the image control unit 19. The image display control unit 14 corrects the color information of the projected image by reflecting the color correction information on each pixel of each of the image projection elements 13R, 13G, and 13B with respect to the image data input from the external input unit 10. Then, the image is projected onto the projection plane 2. The same applies to the case where an image from a memory inserted in the memory card insertion unit 11 is projected. As a method of reflecting the color correction information on the image projection element, there is a method of creating image information by adding color correction information to the image information originally intended to be projected, or color correction information for making the color of the projection plane 2 substantially uniform. First, there is a method of creating a signal for making a color uniform and adding the information of an image to be originally projected to the signal to create a signal.

  As described above, in the projector 1 according to the embodiment of the present invention, the white information projected from the projector 1 onto the projection plane 2 is detected by the color information detected for each pixel by the CCD 16 built in the projector 1. Surface 2 color information is used. Based on the acquired color information, correction for setting the projection plane 2 to a predetermined color (or white) and luminance is performed, and color correction information of each pixel is acquired. By correcting the color information of the input image from the outside based on the acquired color correction information, the projection image in which the color information of the input image is corrected according to the color of the projection surface 2 can be projected onto the projection surface 2. It becomes possible.

  For example, if the color of the projection plane 2 is corrected to white, an image when the original color of the projection plane 2 is corrected to white is projected. Further, when the projection surface 2 has a light color, an image when the color of the projection surface 2 is changed to this light color is projected. If sufficient image quality can be obtained even if the color of the projection surface 2 is light and not white, this correction method can provide a sufficient effect.

  Further, when there is uneven color on the projection surface 2, it is possible to maintain the image quality by eliminating the uneven color on the projection surface 2 and making the projection surface 2 white or light.

  In addition, when there is a light color pattern on the projection surface 2, the projection surface 2 is made to have a uniform color by matching the color of the projection surface with the light color pattern, thereby preventing the pattern from affecting the image. be able to.

  In addition, since the positions of the pixels of the image projection elements 13R, 13G, and 13B on the projection surface 2 correspond to the positions of the pixels of the CCD 16, the color and brightness of each pixel can be detected and corrected. Thereby, when a significant change is detected in the color or brightness of the pixels adjacent to each other of the CCD 16, by performing processing such as averaging processing using color information of a plurality of pixels in the vicinity of the changed pixel, It is possible to blur a boundary by correcting a sharp change in color or luminance between pixels. As a result, it is possible to reduce the difficulty of viewing the image.

  In the above description, the color correction has been described in detail. However, the luminance of each pixel can be calculated from the color information of each pixel obtained from the CCD 16, and the luminance correction is performed in the same manner to correct the color of the input image. Needless to say, it is utilized.

  The above-described embodiment is merely an example, and is not limited to the above-described configuration and shape, and can be appropriately modified and changed within the scope of the present invention.

An example of the state which projects the image on the wall with the projector concerning embodiment of this invention is shown. 1 is a block diagram showing a schematic configuration of a projector according to an embodiment of the invention. 2 shows an example of a positional relationship between pixels of an image projection element and an imaging element on a projection surface of a projector according to an embodiment of the present invention. 2 shows an operation flowchart of the projector according to the embodiment of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projector 2 Projection surface 3 Wall surface 4 Floor stand 10 External input part 11 Memory card insertion part 12 Projection optical system 13 Image display part 14 Image display control part 15 Light source 16 Image sensor (CCD)
17 Image processing unit 18 Storage unit 19 Image control unit 20 Manual input unit

Claims (5)

An image projection element having a plurality of pixels forming a projection image;
A projection optical system that projects an image formed by the image projection element onto a projection surface;
An imaging unit that captures a projection image projected onto the projection plane via the projection optical system;
An image processing unit that obtains the color and brightness of each of the plurality of pixels of the projection image projected on the projection plane imaged by the imaging unit;
An image correction unit that calculates image correction information for each of the plurality of pixels for projecting a uniform image on the projection plane from a projection image captured by the imaging unit;
And an image forming control unit for correcting the projection image formed by said image projection device by said image correction information calculated by the image correcting unit,
The color and brightness for each of a plurality of pixels of the corrected projection image projected on the projection plane obtained by imaging the projection plane on which the projection image corrected by the image formation control unit is projected. When the image correction unit determines whether or not the color and the brightness are substantially constant, the image formation control unit corrects the input projection image based on the image correction information. Project onto the projection surface,
When the color and the luminance is determined not to become substantially constant, the whether the luminance is within a predetermined percentage of the maximum brightness of the projector the image correcting unit is determine a constant,
When the luminance is not within the predetermined ratio of the maximum luminance, the image formation control unit corrects the input projection image based on the image correction information and projects the input projection image on the projection plane,
When the luminance is within the predetermined ratio of the maximum luminance, the image display unit increases the luminance of light projected onto the projection plane by a predetermined amount, and is projected again onto the projection plane by the imaging unit. Shooting of a projected image, acquisition of color and brightness for each of the plurality of pixels by the image processing unit of the captured projection image, and projecting a uniform image from the projected image to the projection plane by the image correcting unit A projector for performing calculation of the image correction information for correction and correction of the projection image formed by the image projection element based on the image correction information by the image formation control unit.   The projector according to claim 1, further comprising an adjustment unit that adjusts the image correction information calculated by the image correction unit. The image projection element projects a uniform image when the image correction unit calculates the image correction information,
3. The image correction unit according to claim 1, wherein the image correction unit calculates image correction information so as to obtain a uniform image of a color that is most frequently present in a projection image captured by the imaging unit. projector. The image projection element projects a white uniform image when the image correction unit calculates the image correction information,
The projector according to claim 1, wherein the image correction unit calculates image correction information so that a projection image captured by the imaging unit becomes a white uniform image. Each pixel of the image projection element is associated with a pixel of the imaging element,
The projector according to any one of claims 1 to 4, wherein the image correction information is calculated for each pixel of the image projection element.

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