JP6550688B2 - Projection device - Google Patents

Description

  The present invention relates to a projection apparatus for projecting projection light.

  There is known a keystone correction function (trapezoidal distortion correction function) in which the projection image is corrected in advance so that the projection image is not deformed into a trapezoid or the like even if the projection direction of the projector is inclined with respect to the projection plane. The projector can project a rectangular projection image on the projection surface by projecting the projection image after deforming the shape of the projection image from a rectangle.

  However, the conventional projector can perform keystone correction of the projected image and enlargement / reduction of the projected image, but it is difficult to flexibly change the projected image.

  On the other hand, a technique for projecting a projected image in a shape desired by a user has been devised (see, for example, Patent Document 1). In Patent Document 1, a projection range and light are projected according to a user operation. Projection range setting means for setting a non-projection range to be set, projection light data correction means for correcting projection light data so as to project light onto the projection range set by the projection range setting means, correction by projection light data correction means Projection light correction data drawing means for drawing the projection light correction data, and a light projection device for projecting light using the projection light drawing data generated by the projection light correction data drawing means Is disclosed.

  By the way, as the screen size and the definition of the projector are increased, it is possible for the user to grasp the contents even if the projected image is projected on a part of the projection surface. However, if a large flat surface can not be secured as the projection surface, the conventional projector can not flexibly change the projection surface. Therefore, in order to project the projection image on a part of the projection surface, the user correctly changes the installation location of the projector Must.

  In addition, as a need for a projection image of a projector, there are two screens and multiple screens of the projection image. This is a need to reduce the number of projectors or to reduce the cost by projecting a plurality of images with one projector. However, in this case as well, if a flat projection surface for two screens cannot be secured, the user cannot use the function of the projector that can project a plurality of images.

  Therefore, as a user using a large-screen high-definition projector or a projector capable of projecting multiple screens, it is possible to make one or more projection images flexible so that they become rectangular after projection on a projection plane that is not all one plane. It is considered preferable to be able to project to

  However, the optical projection apparatus described in Patent Document 1 has a problem that the user must designate a projection area even if the shape of the projection image can be changed. Moreover, in the conventional projector including the light projection device described in Patent Document 1, there is a problem that it is difficult to meet such needs.

  In view of the above problems, an object of the present invention is to provide a projection apparatus capable of projecting a projection image flexibly on a projection surface by reducing user operations.

The present invention is a projection apparatus for projecting projection light, wherein the projection light is based on distance information detection means for detecting the distance of the projection expected range of the projection light and distance information detected by the distance information detection means. Projection possible area detection means for detecting the projectable area of the projection area; projection range setting means for setting a projection area for projecting the projection light whose distortion has been corrected among the areas detected by the projectable area detection means; Projection light data correction means for correcting projection light data according to the projection range set by the projection range setting means;
The projectable area detecting means, based on the distance information, a first determination means for determining whether the horizontal and vertical distance information are equal the projection expected range, by the first judging means If it is not equal, the horizontal direction and the second determination means for determining whether it is possible to approximate the distance information in the horizontal and vertical directions by a linear equation, the second determination means of the projection expected range If it is determined the distance information between the can be approximated by a linear expression, but the horizontal direction of the projection expected range in the range that could be approximated not parallel to the projection device it is determined to be a plane, the distance information of the horizontal direction If it is determined that can not be approximated by a linear equation can be approximated to the first determination means determines that there is a portion at least not flat, the distance information of the vertical direction by the second judging means in a linear expression in the horizontal direction If it is determined, if it is a vertical direction of the projection expected range in the range that could be approximated not parallel to the projection apparatus is determined is determined that the plan can not be approximated distance information of the vertical direction by a linear equation And a second judging means for judging that there is at least a non-flat portion in the vertical direction, wherein the first judging means judges to be a plane in the horizontal direction, and the second judging means has the vertical direction. The projected planned area determined to be a plane is detected as a projectable area of the projection light .

  It is possible to provide a projection apparatus capable of projecting a projection image flexibly on a projection plane while reducing user operations.

It is an example of the figure explaining the image correction by the projector of this embodiment. It is an example of the block diagram of a projection apparatus. It is an example of the block diagram explaining the function of an image process part. An example of the flowchart figure which shows the procedure in which an image process part correct | amends projection image data is shown. It is an example of the top view explaining the relationship between the distance to a projection surface, and a projection image. It is an example of the figure explaining the projection screen at the time of carrying out keystone correction | amendment. It is an example of a figure explaining detection of a projectable range using distance data by a projectable range detection part. It is an example of the figure explaining the coordinate of the rectangular area | region abde among distance images. It is an example of the flowchart figure which shows the procedure which a projection possible range detection part detects a projection possible range. It is an example of the figure which shows the plane (projectable range) detected from the distance image in three-dimensional space. It is an example of the flowchart figure which shows the procedure in which a projection range setting part sets a projection range. It is a figure which shows an example of the projection range set in order to correct the set projection range and the trapezoid distortion, respectively. It is an example of the figure explaining correction | amendment of a projection range. It is an example of the figure which illustrates correction | amendment of projection image data typically. It is an example of the figure explaining the example of a projection when a projection device projects correction | amendment projection image data toward the wall which is not a plane.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an example of a diagram for explaining image correction by the projection device of the present embodiment. A projection device is arranged towards the corner made by the two walls.
I. First, the projection device acquires distance data to the projection image projected on the projection plane.
II. For example, the projection image is captured by the imaging unit, and a distance image including distance data is acquired for each pixel. The distance image is captured in substantially the same range as the projection image.
III. The distance data of the distance image is analyzed to detect a plane corresponding to the wall.
IV. From each plane, a projection range of the same aspect ratio (16: 9 in the figure) as projection image data is detected.
V. The projection range is corrected so that the trapezoidal distortion is corrected on the projection plane using the distance data. Projection image data is mapped to the corrected projection range. For example, black pixels are set to pixels other than the corrected projection range.

  By the above processing, even if the projection surface is not flat, the image data projected on each plane can be appropriately corrected by detecting a plurality of planes from the projection surface based on the distance data.

  In addition, since a plurality of planes are detected, a single projection apparatus can correspond to a multi-screen that projects a plurality of the same projection images or projects different projection images. Thereby, the number of projectors can be reduced and the cost can be reduced.

In the following description, terms used in the present embodiment are defined.
Projection image data: Image data to be projected (In this case, the projection image is projection light and projection image data is projection light data.)
Projection image: Displayable object projection range where projection image data is projected on a plane etc .: Surface projection range suitable for projection among planes analyzed from distance data: Range of the same aspect ratio as projection image data in projection possible range Corrected projection range: Projection range corrected projection image data corrected for distortion correction: Projection image data mapped to the corrected projection range [Configuration example]
FIG. 2 shows an example of a configuration diagram of the projection apparatus. The projection apparatus 100 includes an image signal input unit 21, a data communication unit 22, an image data storage unit 23, an image processing unit 24, an image projection unit 25, a motor control unit 30, a motor 31, an optical system 32, a distance detection unit 28, and control. A unit 34, an operation unit 29, and a ROM 33. Both the data communication unit 22 and the image signal input unit 21 are input units for inputting image data to be projected. The data communication unit 22 receives image data of a digital signal (for example, a format such as JPEG, MPEG2, H. 262, GIF, etc.) via a LAN or a USB cable. The communication method may be either wired communication or wireless communication. When using wireless communication, any communication standard such as Bluetooth (registered trademark), NFC communication, TransferJet, etc. may be used other than wireless LAN.

  Further, the image signal input unit 21 is an input unit for inputting analog video signals such as a D-Sub terminal and a composite terminal, or for inputting a digital video signal such as DVI-D and HDMI (registered trademark). It is an input unit. The image signal input unit 21 converts these video signals into image data of a predetermined format such as JPEG. The image data storage unit 23 is a storage unit called a memory or a buffer that stores image data.

  In the present embodiment, image data can be acquired from both the image signal input unit 21 and the data communication unit 22. Alternatively, a plurality of at least one of the image signal input unit 21 and the data communication unit 22 exist, and a plurality of image data can be acquired. Thereby, the projection apparatus can project different image data simultaneously.

  The control unit 34 controls the entire projection apparatus 100. The control unit 34 is a microcomputer provided with a CPU, a RAM, an interrupt controller, an input / output I / F, and the like, and executes a program stored in the ROM 33. When the user inputs an operation for projecting a projection image to the operation unit 29, the control unit 34 starts projecting the projection image.

  The image processing unit 24 performs correction processing of projection image data, which will be described later, on the image data. The image processing unit 24 is connected to the scaling processing unit 26 and the keystone correction unit 27, and can also perform image processing using this. The image processing unit 24 may be implemented by an IC or the like, or may be a function realized by software when the control unit 34 executes a program.

  The scaling processing unit 26 scales the projection image data in accordance with the resolution of the image projection unit 25. For example, when the projection image data is 1920 × 1200 and the resolution of the image projection unit 25 is 1024 × 768, the projection image data is changed to a resolution of 1024 × 768.

  The keystone correction unit 27 deforms the projection image data so that the projection image distorted into a rectangular solid or a rectangle other than a square becomes a rectangle. The keystone correction unit 27 generates a pattern image (distorted into a rhombus, parallelogram, trapezoid, or the like) indicating a range of a projected image having a specific aspect ratio such as 4: 3 or 16: 9, and the projected image Transform the data into the shape of the pattern image. Thereby, the projection image projected on the plane becomes a rectangle.

  The image projection unit 25 converts projection image data into light and projects the light according to, for example, a predetermined projection method. As a projection method, there are a DLP method using a micro mirror, an LCD method using a transmissive liquid crystal, an LCOS method using a reflective liquid crystal, and the like. In the present embodiment, any projection method may be used.

  The projection apparatus 100 has a scaling function, and the control unit 34 outputs a control signal corresponding to the set magnification to the motor control unit 30. The motor control unit 30 controls the motor 31 that can move the lens of the optical system 32 in the optical axis direction, and enlarges / reduces the projection image to the set magnification by determining the lens position.

  The distance detection unit 28 detects the distance from the object on which the projection image is projected. The distance is preferably detected for each pixel, but may be detected for each predetermined pixel block. This is because the difference in distance between pixels becomes small as the resolution increases. By obtaining the distance data for each pixel block, the processing load can be reduced. Examples of the distance detection unit 28 include a stereo camera, a camera capable of detecting a distance by a time-of-flight method, and a laser radar.

  In order to detect the distance by the stereo camera, the parallax is calculated by block matching the two images, and the distance is calculated from the focal length and the base length. Image data in which distance data is included in a pixel or pixel block is called a distance image.

  The distance detection unit 28 may be fixed to the projection apparatus 100, but may be detachable. When it is detachable, the distance detection unit 28 communicates with the projection apparatus 100 via a wireless I / F such as Bluetooth, IC communication, infrared communication, and wireless LAN, and transmits distance information.

  The operation unit 29 receives a user's operation. The operation unit 29 is, for example, a hard key arranged on the projection apparatus 100. Moreover, in order to receive operation by a remote control, you may have an infrared receiving part, for example. An operation menu projected by the projection apparatus 100 may be used as the operation unit 29. In this case, since the projection apparatus 100 projects the operation menu from the image projection unit 25, the user can perform a desired operation by moving the cursor with the hard key or the remote control and pressing the determination key. The operation unit 29 can receive various operations such as reduction / magnification scaling factor, brightness, and setting of correction amount of keystone correction. Note that the operation unit 29 may include a liquid crystal display unit and a touch panel, and accept operations from the touch panel.

  A program 40 is stored in the ROM 33. The program 40 is a program executed by the CPU of the control unit 34. Further, when the image processing unit 24 is realized as software, a program for the control unit 34 to perform correction processing for correcting projection image data is also included. The program 40 may be downloaded from a server (not shown) via the data communication unit 22, or may be distributed in a state stored in a memory card or the like.

[Function and operation procedure]
FIG. 3 is an example of a block diagram for explaining the function of the image processing unit 24. As shown in FIG. The projection apparatus 100 includes a projectable range detection unit 35 that detects a range in which the projection apparatus 100 can project a projection image using distance data and the like, and a projection range that uses the projectable range detected by the projectable range detection unit 35. And a projection image data correction unit 37 for correcting the projection image data using the projection range set by the projection range setting unit 36 to create corrected projection image data.

  FIG. 4 shows an example of a flowchart showing a procedure of the image processing unit 24 correcting projection image data.

  First, the projectable range detection unit 35 acquires distance data (S1).

  Next, the projectable range detection unit 35 detects the projectable range using the distance data (S2).

  Next, the projection range setting unit 36 sets a projection range having the same aspect ratio as the projection image data in the projectable range (S3).

  Next, the projection range setting unit 36 performs distortion correction on the projection range (S4).

Next, the projection image data correction unit 37 maps the projection image data to the corrected projection range to create corrected projection image data (S5).
Hereinafter, a description will be given with reference to FIG.

<S1 Acquisition of distance data>
FIG. 5A is an example of a top view for explaining the relationship between the distance to the projection plane and the projection image. As shown in FIG. 5A, the projection apparatus 100 projects a projection image toward the corner portion 51. Thus, the projected image is projected across the left wall 52 and the right wall 53.

  Straight lines 54 and 55 indicate the left end and the right end of the projection range, respectively. The concentric circles drawn on the inner side of the left and right walls 52, 53 are centered on the projection device (for example, the outermost lens of the optical system 32). As is clear from the concentric circles, the distance from the projection device 100 to the left and right walls 52 and 53 is not constant, and the distance increases as the distance from the corner 51 increases.

  FIG. 5B shows an example of projection image data input to the projection apparatus 100 to project an image. As described above, the projection image data is rectangular image data having a fixed aspect ratio. The projection image is enlarged according to the distance between the projection device 100 and the walls 52 and 53.

  FIG. 5C is an example of a diagram showing a projection image projected toward the corner portion 51. As shown in FIG. When the distance from the projection device 100 to the walls 52 and 53 is short, the projection image data is displayed small, and when the distance is long, the projection image is displayed large. Therefore, when the projection image data of FIG. 5B is projected toward the walls 52 and 53, the vertical length of the projection image data becomes shortest at the positions of the straight lines 54 and 55 and becomes longest at the corner portion 51.

  For this reason, when a projected image is projected onto a wall without any correction, the projected image has a large center and is displayed smaller toward both ends. Focusing on only one wall, the projection range is deformed into a trapezoid.

  As shown in FIG. 5, a correction that electronically cancels distortion to a trapezoid, a rhombus, a parallelogram, etc. that occurs when the optical axis of the projection device 100 is not perpendicular to the projection plane is a trapezoidal distortion correction (also called keystone correction). Is a keystone distortion correction to distinguish it from the keystone correction by the keystone correction unit 27). When the projection apparatus 100 performs trapezoidal distortion correction, the projection image data is corrected inside the projection apparatus 100 so that the projection image has a correct shape (a rectangle having the same aspect ratio as the projection image data), and the corrected projection image data Generate

  A projection screen when trapezoidal distortion correction is performed will be described with reference to FIG. FIG. 6A is the same top view as FIG. FIG. 6B is a diagram illustrating an example of the projection image data obtained by dividing the projection image data into left and right and having the trapezoidal distortion correction performed on each of the left and right projection images. In trapezoidal distortion correction, the projection image data is distorted in the direction opposite to the trapezoidal distortion. That is, correction is performed so that an image projected on the wall becomes small at a position (for example, the corner portion 51) where the distance from the projection device 100 is long. Each of the projection image data divided into right and left parts is subjected to trapezoidal distortion correction so that it has a shape having triangular notches in the upper and lower sides.

  FIG. 6C is an example of a diagram showing a projection image obtained by projecting the trapezoidal distortion corrected projection image data toward the corner portion 51. By projecting the corrected projection image data as shown in FIG. 6B, a rectangular projection image is obtained.

  Although the correction of the projection image data in FIG. 6C is different from the correction of the projection image data of the present embodiment described later, it can be corrected as shown in FIG. 6C.

  In order for the projection apparatus 100 to perform such trapezoidal distortion correction, it is necessary to correctly grasp the positional relationship between the wall and the projection apparatus 100. Specifically, it is detected where the wall 52 and the corner portion 51 of the wall 53 are, how far is the distance between the front and back sides of the wall 52, how long is the distance between the front and back sides of the wall 53, etc. There is a need. In the present embodiment, as described below, it is possible to obtain information corresponding thereto and to project projected images on the walls 52 and 53, respectively.

  FIG. 7 is an example of a diagram for explaining detection of a projectable range using distance data by the projectable range detection unit 35. Similarly, the projection device 100 projects the projection image onto the corner 51 of the two walls.

  First, when the projection apparatus 100 projects onto a flat projection plane that does not actually exist, the projection range is a rectangular area connecting the vertices abde. On the other hand, the projection range projected on the non-plane formed by the two walls 52 and 53 is an area connecting the vertices abcdef.

  The distance detection unit 28 acquires distance data in a range at least as large as the projected image abcdef. In addition, preferably, the distance detection unit 28 acquires distance data in the same range as the projection image abde. That is, since the pixels of the distance image correspond to the pixels of the projection image data, the projection range obtained from the distance image can be set in the projection image data. The resolutions of the projection image data and the distance image may be different, and in this case, the pixels of one distance image may be associated with the pixels of a plurality of projection image data. Therefore, the area connecting the vertices abcdef is a rectangular area. The area connecting the vertices abcdef is an example of a projected area within the scope of the claims.

  Even if the entire projection image abcdef is not obtained, it is possible to detect a plane by detecting the projection image abde. Note that the projection image abcdef may be detected from the distance image using a luminance value or the like.

  The acquisition density of the distance data varies depending on the distance detection principle of the distance detection unit 28, but has an acquisition density sufficient for correcting the projection image data (for example, the extent that jaggies are not found by the correction of the projection image data). ing. For example, when the distance detection unit 28 is a stereo camera, distance information can be acquired for each pixel. In the case of a TOF camera, one piece of distance information can be acquired for at least one to several pixels. When the distance detector 28 is a laser radar, distance information can be acquired according to the control resolution in the irradiation direction of the laser light.

  If distance data of the projection range is obtained in this way, a plane can be detected as described below. The plane is the two walls 52 and 53 in the case of FIG.

<S2 Detection of Projectable Range>
FIG. 8A is an example of a diagram for explaining the coordinates of the rectangular area abde in the distance image, and FIG. 8B is an example of a diagram for schematically explaining the distance data of the rectangular area abde. (X, y) in FIG. 8A represents the coordinates of the distance image in which the distance data is stored. The x-coordinate is the horizontal coordinate of the distance image, and the y-coordinate is the vertical coordinate of the projection range.

  As shown in FIG. 8B, the x coordinate is 1 to 23 and the y coordinate is 1 to 20, but the distance data may be detected more finely. Looking at the distance data along the x coordinate, the distance data is the largest at x = 14, 15, and the distance data becomes smaller the closer to x = 1 or x = 23. Further, when the distance data is observed along the y-coordinate in the vicinity of x = 14, 15, x = 1, or x = 23, it is substantially constant.

  From these distance data, it can be estimated that the rectangular area abde of the projection range straddles two vertical walls, and there is the deepest part of the corner 51 where the two walls intersect at x = 14, 15. More specifically, it can be estimated that a range in which a plurality of x-coordinates having substantially constant distance data along the y-coordinate is continuous is flat. On the other hand, when the distance data along the x-coordinate does not increase or decrease uniformly (from increase to decrease or from decrease to increase), it can be determined that the corners of the two planes have been reached. If this is utilized, a plane can be detected from distance data.

  The details will be described below. The projectable range detection unit 35 analyzes the distance data and detects a continuous plane on the projection plane. The continuous plane is determined to be a projectable range. Specifically, it can be determined by comparing adjacent distance data.

  First, let the coordinates of the top left vertex of the projection range be (1,1). The distance data of coordinate (1, 1) is 40. Next, referring to the distance data of coordinates (2, 1), the distance data is 50. Since the coordinates (1, 1) and the coordinates (2, 1) are not the same distance, it can be seen that the X axis direction of the projection range is not perpendicular to the optical axis of the projection apparatus 100.

On the other hand, when two points of distance data 40 of coordinate (1, 1) and distance data 50 of coordinate (2, 1) are approximated by a straight line in the X-axis direction, the distance data is Z.
Z = 10X + 30
The following linear expression is obtained.

  Next, the distance data of the coordinate (3, 1) is 60, and it can be seen that the linear expression “Z = 10 × + 30” described above is satisfied. That is, the distance data increases from the coordinate (1,1) to the coordinate (3,1) in proportion to the X coordinate. This indicates that the projection range between the coordinates (1,1) and the coordinates (3,1) is a straight line. That is, it can be seen that the X-axis direction of the projection range is a plane that is not perpendicular to the optical axis of the projection apparatus 100.

  Whether the distance data of coordinate (3, 1) satisfies the linear expression "Z = 10X + 30" obtained from the distance data of coordinate (1, 1) and coordinate (2, 1) is judged with a margin You may This is because even if it is a plane, distance data may not be completely on a straight line due to errors or the like.

  For example, when the distance data at the coordinate (1,1) is 40, the distance data at the coordinate (2,1) is 50, and the distance data at the coordinate (3,1) is 61, the calculation of the coordinate (3,1) Since the difference from the distance data 60 is small, it can be determined that the coordinates (3, 1) are also in the plane. For example, the margin is ± 5%. Since the calculation result of the linear expression obtained from the distance data of the coordinates (1, 1), (2, 1) is 60, the margin is ± 3. Therefore, when the actual distance data of the coordinates (1,3) is 57 to 63, it can be determined that the straight line connecting the coordinates (1,1) to the coordinates (3,1) is in a planar shape.

  The margin may be determined in advance or may be arbitrarily set by the user.

  If it turns out that the straight line connecting coordinates (1,1) to coordinates (3,1) is flat, the straight line connecting coordinates (1,1) to coordinates (4,1) is flat using the same method. Also determine if it is. By repeating this process, a planar range is detected.

  If the distance data of the coordinates of the detection destination whether it is a plane is not a plane, detection of another plane is started from the coordinates.

  The case where the distance data of the adjacent pixels differ by more than the margin with respect to the calculation result of the linear expression will be described. Comparing the distance data of the coordinates (15, 1) and the coordinates (16, 1) in FIG. 8B, it can be seen that the distance data in the X-axis direction is not equal and is not parallel to the projection plane. Next, it is considered whether distance data in the X-axis direction can be approximated by a linear expression. Although the distance data of the coordinates (15, 1) is 170, the calculation result of the linear expression is 180, so that it can be understood that it is out of the margin. For this reason, it can be seen that the plane connecting the coordinates (1,1) to (14,1) and the plane connecting the coordinates (15,1) to (16,1) are different planes.

  In determining whether the planes are continuous, instead of comparing the calculation result of the primary expression and the actual distance data, the parameters of the primary expression may be compared. For example, for coordinates (1, 1) to (14, 1), a linear expression of “Z = 10 × 30” is established in distance data of adjacent coordinates. On the other hand, a linear expression of “Z = −20 (X−15) +170” is established in the distance data of the coordinates (15,1) and the coordinates (16,1). Since the proportionality factor and the y-intercept both differ by more than significant difference, the plane connecting the coordinates (1, 1) to (14, 1) and the plane connecting the coordinates (15, 1) to (16, 1) are different It turns out that it is a plane.

  FIG. 9 is an example of a flowchart illustrating a procedure by which the projectable range detection unit 35 detects the projectable range. The procedure of FIG. 9 starts when the projectable range detection unit 35 acquires distance data.

  First, the projectable range detection unit 35 determines whether the distance data in the X-axis direction are equal (S10).

  If they are equal (Yes in S10), it is determined that the X axis direction of the projection range is parallel to the projection apparatus 100 (S20).

  If they are not equal (No in S10), the projectable range detector 35 determines whether or not the distance data in the X-axis direction can be approximated by a linear expression (S30).

  If approximation is possible with a linear expression (Yes in S30), the projectable range detection unit 35 determines that the X axis direction of the projection range is not parallel to the projection apparatus 100 but is a plane in the approximation range (S40) .

  When approximation cannot be performed using the linear expression (No in S30), the projectable range detection unit 35 determines that there is at least a portion that is not a plane in the X-axis direction (S50).

  Next, the projectable range detection unit 35 determines whether the distance data in the Y-axis direction is equal (S60).

  If equal (Yes in S60), it is determined that the Y-axis direction of the projection range is parallel to the projection apparatus 100 (S70).

  If they are not equal (No in S60), the projectable range detection unit 35 determines whether the distance data in the Y-axis direction can be approximated by a linear expression (S80).

  If approximation is possible with a linear expression (Yes in S80), the projectable range detection unit 35 determines that the Y axis direction of the projection range is not parallel to the projection apparatus 100 but is a plane in the approximation range (S90) .

  When approximation cannot be performed using the linear expression (No in S80), the projectable range detection unit 35 determines that there is at least a portion that is not a plane in the Y-axis direction (S100).

  Next, the projectable range detection unit 35 determines whether all distance data have been determined (S110).

  When not determining all the distance data (No in S110), the process from Step S10 is repeated with reference to the next distance data.

  If all the distance data have been determined (Yes in S110), the procedure of FIG. 9 ends.

  FIG. 10 is an example of a diagram showing a plane (projectable range) detected from a distance image in a three-dimensional space. The detected plane is displayed on the (X, Y, Z) axis. The X axis is the horizontal coordinate of the distance image, the Y coordinate is the vertical coordinate, and the Z coordinate is the distance data.

  In FIG. 10, two planes, plane abcf and plane fcde, are detected in the distance image. These two planes are the projectable range, respectively.

  Although two planes are detected in FIG. 10, three or more planes may be detected. Further, in FIG. 10, flat planes are detected horizontally in the horizontal direction, but may be detected in the vertical direction.

<S3 Projection range setting>
Next, setting of the projection range by the projection range setting unit 36 will be described. The projection range setting unit 36 determines, from the projectable range, a range in which the projection image can be projected with the same aspect ratio as the projection image data.

  FIG. 11 is an example of a flowchart showing a procedure in which the projection range setting unit 36 sets the projection range. The procedure in FIG. 11 starts when the projection range setting unit 36 acquires a projectable range indicated by coordinates as shown in FIG. 10, and performs processing for each projectable range.

  First, the projection range setting unit 36 confirms the aspect ratio of projection image data (S210). In this embodiment, it is assumed to be 16: 9.

  Next, the maximum area that can be displayed with an aspect ratio of 16: 9 in the projectable range is calculated (S220). Specifically, among the lengths in the Y direction and the X direction of the plane abcd in FIG. 10, if the length in the X direction is 16, whether the length in the Y direction equivalent to 9 can be secured or not Determine if The length in the X direction is “14-1 = 13”. Assuming that this is 16, the length in the Y direction corresponding to 9 is “(13/16) × 9”. Since the length in the Y direction is 20, for example, the aspect ratio of 16: 9 using the entire X direction is the maximum area.

  If the length in the Y direction corresponding to 9 of 16: 9 cannot be secured, and the length in the Y direction is set to 9, the length in the X direction corresponding to 16 is determined to be 16: 9. Determine the maximum area of aspect ratio.

  Note that the position of the maximum region may be, for example, the center in the vertical direction or the horizontal direction of the plane abcd.

  Next, the number of pixels in the maximum area is calculated (S230). That is, the product of the number of pixels in the X direction and the number of pixels in the Y direction of the maximum region is calculated. This is because when the number of pixels is small, a rough projected image is obtained. Since trapezoidal distortion correction is performed as will be described later, it is impossible to project using all the pixels in the maximum area, and for example, 0.9 (for example, 90% is used) for the number of pixels in the maximum area. You may multiply by. Alternatively, the number of pixels after trapezoidal distortion correction may be calculated as shown in FIG. 11 described later.

  Then, it is determined whether or not the number of pixels is equal to or greater than a threshold (S240). Note that each of the number of pixels in the X direction and the number of pixels in the Y direction may be compared with a threshold.

  If it is not equal to or greater than the threshold value (No in S240), it is determined that the quality of the projected image is low even if it is projected, and it is determined that the focusable projection range is unavailable (S270). That is, the projectable range is excluded from the plane or the projection range.

  When the number of pixels is equal to or greater than the threshold (Yes in S240), the projection range setting unit 36 determines whether the area when the image of the maximum area is projected is equal to or greater than the threshold (S250). Since the distortion-corrected projection image is rectangular, the length “14-1” in the X direction of the plane abcce and the length “20” in the Y direction are respectively the distances to the projection plane (distance data 40 of X = 1) When enlarged, the length in the X direction and the length in the Y direction of the projection screen can be obtained. Thus, the projected area can be easily obtained.

  When the area when projecting the image of the largest area is not more than the threshold (No in S250), it is judged that the user can not view the projected image with high visibility even if the projection is performed, and the focused possible area can not be used It is determined that (S270).

  If the area when projecting the image of the largest area is equal to or larger than the threshold (Yes in S250), it is determined that the focused projectable range is available (S260).

  The projection range setting unit 36 determines whether or not all planes have been determined (S280).

  If all the planes have not been determined (No in S280), the processing from step S210 is performed with reference to the next projectable range (S290).

<S4 Projection Range Distortion Correction>
FIG. 12A shows an example of the set projection range. A projection range of 16: 9 is secured in each of the two projectable areas. When the projection image data is arranged in the entire projection range, trapezoidal distortion occurs on the projection surface, and thus the projection image data is subjected to trapezoidal distortion correction.

  Since the degree of trapezoidal distortion correction varies depending on the inclination of the projection apparatus 100 and the projection plane, the projection range setting unit 36 corrects the projection range using the distance data.

  Further, since the obtained range of the projection image abde and the distance data is the same, the projection range in FIG. 12A corresponds directly to the projection image data. Therefore, a range corresponding to the projection range of the image memory in which the projection image data is stored can be specified based on the coordinates of the projection range of the distance image.

FIG. 13 is an example of a diagram for explaining the correction of the projection range. FIG. 13A is an example of a diagram for explaining the relationship between the size of a projection element for projecting projection image data and the size H of a projection image on a projection plane. The height of the projection element was h. The image produced by the projection element is magnified by the optics, but the magnification of the optics is fixed or known. Also, although the projected image becomes larger according to the distance L, its proportional coefficient is α. α is known.
H = α ・ L ・ h
In the present embodiment, h is the size of the projection element corresponding to 9 with an aspect ratio of 16: 9, but since the number of pixels in the projection range has already been obtained, H can be calculated from this equation. Although the figures are described using the sizes h and H in the height direction, the relationship between the proportional coefficient α and the distance L is also the same in the size in the lateral direction.

  FIG. 13B is an example of a diagram schematically showing distance data of the plane fcde. The distance data for X = 15 is about 170, and the distance data for X = 23 is about 10. Therefore, the distance between the right end in the vicinity of the plane fcde and the far end is different by “170−10”.

  Since the influence of the distance L on h can be expressed by “h = H / α · L” from the above equation, setting “170−10” to L corrects trapezoidal distortion, so X = At 15, it is possible to calculate how much h should be reduced. The size of the projection element at X = 15 calculated in this manner is h ′. Since h ′ can be calculated in the same manner for the plane abcf, the description is omitted.

  FIG. 12B is a diagram showing an example of a projection range deformed to correct trapezoidal distortion. At the right end of the plane abcf where the distance data increases and the left end of the plane fcde where the distance data increases, the size h of the projection image data in the height direction is corrected to h ′. Thereby, a projection image with an aspect ratio of 16: 9 is obtained on the projection plane.

<S5 Mapping of projection image data>
Next, correction of projection image data will be described. The projection image data correction unit 37 corrects the projection image data read out from the image data storage unit 23 based on the projection range set by the projection range setting unit 36.

FIG. 14 is an example of a diagram for schematically explaining correction of projection image data. It is assumed that the projection image data and the image memory have the same size.
(i) First, an image memory outside the set projection range is filled with a black pixel value or the like. It may be replaced with a white pixel value.
(ii) The entire projection image data is reduced and mapped to the projection range. Any algorithm may be used for mapping. For example, projective transformation is performed. Projective transformation is performed as follows, for example. Coordinates of the projection range are represented by (u, v), and coordinates of projection image data are represented by (x, y). Further, u and v are represented by x and y, where a, b, c, d, e, f, g and h are transformation coefficients.
u = x · a + y · b + c-x · g · u · y · h · u
v = x · d + y · e + f-x · g · v-y · h · v
Since the four vertices of the projection range correspond to the four vertices of the projection image data, the coordinates of the vertices are assigned to u, v, x, and y, respectively, and conversion coefficients are a, b, c, d, e, f, g and h are calculated. Since there are two values of x and y at the four vertices, eight conversion formulas can be obtained and each variable relation coefficient can be determined. Knowing the transformation coefficients, we can transform any x, y into u, v.
(iii) The projection image data mapped to the black pixel value and the projection range is the corrected projection image data. The corrected projection image data is output to the image projection unit.

  Here, the same projection image data may be reduced and mapped to the projection range set on the plane fcde, or another projection image data may be mapped. By mapping different projection image data, one projection device 100 can simultaneously project different projection images.

  If only one type of projection image data is required and only one projection area is required, the projection image data need only be mapped to the larger projection range.

[Example of projected image with plane distance correction]
FIG. 15 is an example of a diagram for explaining an example of projection in the case where the projection apparatus 100 projects the corrected projection image data toward the non-planar wall. Although the projection image is projected across two walls not parallel to the projection apparatus 100, since the projection image data is subjected to planar distance correction, a rectangular projection image can be projected on each of the two walls.

  In addition, since the number of projection planes can be increased to two as many as the number of planes, the degree of freedom in projection can be increased. The user does not need to set a projection range.

  With regard to multi-screen projection in which a plurality of different projection images are projected by one projection apparatus 100, a plane can be found from distance data, and projection can be performed after correcting the projection image data.

  Therefore, even if the projection surface is not flat, the projection apparatus according to the present embodiment can appropriately correct the image image data projected on each plane by detecting a plurality of planes from the projection surface based on the distance data.

  In addition, since a plurality of planes are detected, one projection device can project a plurality of identical projection images or correspond to a multi-screen on which different projection images are projected. Thereby, the number of projectors can be reduced and the cost can be reduced.

  The best mode for carrying out the present invention has been described above with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the present invention. And substitutions can be added.

  For example, instead of detecting each plane and setting it as a projectable area, a projectable area that satisfies the aspect ratio may be detected from all of the plurality of planes in a plurality of planes sharing the side (FIG. 6 (c) ). After detecting each plane, comparing the X coordinates of the ends of the planes reveals that the two planes share a side. Then, if the projection image data is divided according to the coordinates of the plane and mapped to the projection range, one rectangular projection image can be projected across a plurality of planes.

24 image processing unit 25 image projection unit 28 distance detection unit 29 operation unit 34 control unit 35 projectable range detection unit 36 projection range setting unit 37 projection image data correction unit 100 projection apparatus

Patent No. 4341723

Claims (6)

A projection device for projecting projection light,
Distance information detection means for detecting the distance of the projected projection range of the projection light;
Projectable area detection means for detecting a projectable area of projection light based on distance information detected by the distance information detection means;
Projection range setting means for setting a projection range for projecting the projection light whose distortion has been corrected among the areas detected by the projectable area detection means;
Projection light data correction means for correcting projection light data according to the projection range set by the projection range setting means;
The projectable area detecting means includes
Based on the distance information, a first determination means for determining whether the horizontal and vertical distance information are equal the projection expected range,
If it is not equal by said first determining means, second determining means for determining whether it approximates the distance information in the horizontal direction and the vertical direction of the projection expected range by a linear equation,
If it is determined that it approximates the distance information of the horizontal direction by a linear equation by the second judging means judges that the extent that approximated the horizontal direction of the projection expected range is a plan not parallel to the projection device A first determination unit that determines that there is at least a non-planar portion in the horizontal direction when it is determined that the horizontal distance information can not be approximated by a linear expression ;
If it is determined that it approximates the distance information of the vertical direction by a linear equation by the second judging means judges that the extent that approximated the vertical direction of the projection expected range is a plan not parallel to the projection device And second determining means for determining that there is at least a non-planar portion in the vertical direction when it is determined that the vertical distance information can not be approximated by a linear expression .
Detecting the projected planned area determined to be a plane in the horizontal direction by the first determination means and the plane determined in the vertical direction by the second determination means as a projectable area of the projection light A projection apparatus characterized by the above. The projection range setting means excludes the projectable area which can not project the projection light with a predetermined quality or more among the projectable areas detected by the projectable area detection means. Item 4. The projection device according to Item 1. The projection range setting means excludes the projectable area in which the area of the projection light to be projected is equal to or less than a threshold among the projectable areas detected by the projectable area detection means. Item 4. The projection device according to Item 1. The projection range setting means is characterized by excluding the projectable area in which the number of pixels of the projection light to be projected is equal to or less than a threshold among the projectable areas detected by the projectable area detection means. The projection apparatus according to claim 1. The projection range setting means sets, as the projection range, a range where the same aspect ratio as the projection light data is secured among the projectable areas detected by the projectable area detection means.
The projection device according to any one of claims 1 to 4, characterized in that: The projection range setting means performs trapezoidal distortion correction on the projection range using a difference between the farthest distance information and the nearest distance information in the projection range.
6. The projection apparatus according to claim 5 , wherein the projection light data correction means corrects projection light data by mapping the projection light data to the projection range on which the trapezoidal distortion correction has been performed.

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