Patent Description:
Conventionally, projection devices that can project an image onto, for example, a screen have been known. As a technique relating to projection devices, <CIT> discloses a method for displaying an object included in a design plan and object data on the design plan on a boundary wall surface of a room.

<CIT> describes a construction support apparatus, for projecting and displaying the image for supporting a construction work on a target plane as a work target, including: a keystone information obtaining means for obtaining keystone information used for correcting distortions in the projected image generated due to an angle between the target plane and a projection light; a construction support image generating meansfor generating a predetermined construction support image; a keystone correcting meansfor implementing image processing for correcting a keystone in the construction support image, based on the keystone information; and an image projecting meansfor projecting the construction support image on the target plane, after the keystone in the construction support image is corrected.

<CIT> describes a setting-out support device that supports the setting-out to an architectural structure. Specifically, the setting-out support device includes: a projection unit for projecting an image to an object surface for setting-out in an architectural structure; and a projection image control unit that determines the size of the image to be projected on the basis of the distance between the object surface and the setting-out support device, determines the position of the image to be projected on the basis of the position, on the object surface, of the foot of a perpendicular from the setting-out support device to the object surface, and projects the image to the projection unit at the determined position and size of the image to be projected.

<CIT> describes a full scale plan projection system including a processor and projector for displaying full scale building plans at a construction site or in a showroom.

In the method disclosed by <CIT>, an association between a reference device and a design plan is formed using a known reference object. Accordingly, a plurality of reference objects need to be placed in conspicuous positions inside a space in advance.

The present invention provides a projection method, a projection device, and a projection system which can readily form an association between a position in drawing data and a position in a projection plane onto which the drawing data is projected.

The present invention relates to a projection method according to claim <NUM>, a projection device according to claim <NUM>, and a projection system according to claim <NUM>. Claims <NUM> to <NUM> refer to specifically advantageous realizations of the projection method according to claim <NUM>.

A projection method, a projection device, and a projection system according to the present invention can readily form an association between a position in drawing data and a position in a projection plane onto which the drawing data is projected.

Hereinafter, embodiments will be described in detail with reference to the drawings. Note that the embodiments below each describe a general or specific example. The numerical values, shapes, materials, elements, the arrangement and connection of the elements, steps, and orders of the steps, etc. presented in the embodiments below are mere examples, and are not intended to limit the present invention. Furthermore, among the elements in the embodiments below, those not recited in any one of the independent claims will be described as optional elements.

Note that the drawings are schematic diagrams, and do not necessarily provide strictly accurate illustration. Throughout the drawings, the same numeral is given to substantially the same element, and redundant description may be omitted or simplified.

First, an overview of a projection system according to an embodiment will be described. <FIG> is a diagram illustrating an overview of operation performed by the projection system according to the embodiment.

Projection system <NUM> according to the embodiment includes projection device <NUM>. Projection device <NUM> is provided in space <NUM> in a building under construction. Projection device <NUM> projects, in actual size, drawing data that is at least a part of architectural design data onto a structure (specifically, a floor, a wall, or a ceiling) creating space <NUM>. The drawing data indicates a marking position in the space, for example. A line of light having a length as designed is projected onto a position where a user, such as a worker for construction work, is to draw a marking line.

With this, the user can readily draw a marking line by tracing the projected line of light. Note that it is not essential that a line of light is used as a guide to draw a marking line. A line of light itself may be used as a marking line.

Note that projection system <NUM> may be able to project a part of or the whole of architectural design data, and drawing data may be data other than data indicating a marking position. For example, if drawing data includes data indicating an installation position of equipment such as a built-in kitchen or a bathtub, projection system <NUM> may project the installation position of the equipment in actual size.

Next, a configuration of the projection system according to the embodiment will be described. <FIG> is a block diagram illustrating a functional configuration of projection system <NUM>. <FIG> is a diagram illustrating an appearance of devices constituting projection system <NUM>. As illustrated in <FIG> and <FIG>, projection system <NUM> includes projection device <NUM> and operation device <NUM>. First, projection device <NUM> will be described.

Projection device <NUM> displays, in actual size, drawing data that is at least a part of architectural design data on a structure. Structures are, specifically, floors, walls, ceilings, and pillars. Projection device <NUM> is attached on a tripod and is provided on a floor, for example. Projection device <NUM> may be secured to a ceiling hanging bolt, or may be provided on a wall. Projection device <NUM> includes communicator <NUM>, distance meter <NUM>, projector <NUM>, controller <NUM>, storage <NUM>, driver <NUM>, angle measurer <NUM>, attaching unit <NUM> (illustrated in <FIG>), and casing <NUM> (illustrate in <FIG>).

Communicator <NUM> is a communication circuit (in other words, a communication module) for projection device <NUM> to communicate with operation device <NUM>. Communicator <NUM> performs wireless communication with operation device <NUM>, but may perform wired communication with operation device <NUM>. A communication standard for communication performed by communicator <NUM> is not particularly limited.

Distance meter <NUM> detects a distance from projection device <NUM> to a structure creating space <NUM>. Distance meter <NUM> is a distance measurement sensor such as a time of flight (TOF) sensor. Distance meter <NUM> may be other distance measurement sensors, such as a distance measurement sensor using a phase difference detection method, or a distance measurement sensor using a triangular distance measurement method. Distance meter <NUM> includes light source for distance measurement 22a and detector 22b.

Light source for distance measurement 22a emits light toward a structure. Light source for distance measurement 22a is implemented by, for example, a light emitting element that emits infrared light, but may be implemented by a light emitting element that emits visible light. Note that, as will be described later, distance meter <NUM> has a laser pointer function for presenting the current distance measurement target point to a user. This function is implemented by a light source different from light source for distance measurement 22a, but in the case where light source for distance measurement 22a emits visible light, the function may be implemented by light source for distance measurement 22a.

Moreover, light source for distance measurement 22a is not necessarily a light source different from light source 23a included in projector <NUM>. That is, light source 23a included in projector <NUM> may be used as light source for distance measurement 22a. More specifically, distance meter <NUM> may be a sensor that includes only detector 22b, without light source for distance measurement 22a.

Detector 22b is a light receiving element that detects reflected light which is light emitted by light source for distance measurement 22a and reflected off a structure. Detector 22b is implemented by, for example, a photodiode.

Projector <NUM> is a projection module for projecting drawing data onto projection plane <NUM>. Projector <NUM> includes light source 23a, and scanner 23b. Note that, although not illustrated, projector <NUM> includes optical components such as a lens, a mirror, etc. other than the elements described above.

Light source 23a is a laser light source implemented by a semiconductor light emitting element, for example. Note that light source 23a may include light emitting elements having different luminescent colors (e.g., a red-light emitting element, a green-light emitting element, and a blue-light emitting element), and may have a configuration capable of switching between the luminescent colors.

Scanner 23b scans, on a structure, light emitted by light source 23a. Scanner 23b is implemented by, for example, a micro electro mechanical systems (MEMS) mirror.

Controller <NUM> is a control device that controls distance meter <NUM>, projector <NUM>, and driver <NUM> for projecting drawing data onto projection plane <NUM>. Controller <NUM> is implemented by, for example, a microcomputer or a processor. Moreover, controller <NUM> may include a driving circuit for driving projector <NUM>, and a driving circuit for driving driver <NUM>.

Storage <NUM> is a storage device that stores drawing data, and a control program to be executed by controller <NUM>. This control program is for projecting drawing data in actual size. Storage <NUM> is implemented by, for example, a semiconductor memory.

Driver <NUM> is a driving mechanism for changing an orientation of projection device <NUM> (in other words, an orientation and an angle of distance meter <NUM>). To be more specific, driver <NUM> changes an orientation of casing <NUM> with respect to attaching unit <NUM>. Driver <NUM> includes first driver 26a for changing an orientation of projection device <NUM> toward a tilt direction, and second driver 26b for changing an orientation of projection device <NUM> toward a pan direction. Each of first driver 26a and second driver 26b is implemented by a rotary driving device such as a motor. Note that driver <NUM> may include a third driver for changing an orientation of projection device <NUM> toward a roll direction. Moreover, driver <NUM> may be a mechanism having a ball-shaped joint.

Angle measurer <NUM> measures an orientation of projection device <NUM> (in other words, an orientation and an angle of distance meter <NUM>). Specifically, angle measurer <NUM> is an angle sensor that measures a driving amount (i.e., a tilt angle and a pan angle) of driver <NUM>. Note that when driver <NUM> includes a third driver for changing an orientation of projection device <NUM> toward a roll direction, angle measurer <NUM> may measure a roll angle as a driving amount of driver <NUM>.

Attaching unit <NUM> is an attaching structure for attaching projection device <NUM> on a tripod. Note that projection device <NUM> may be attached to a ceiling hanging bolt. In this case, attaching unit <NUM> is an attaching structure for attaching projection device <NUM> on a ceiling.

Casing <NUM> accommodates communicator <NUM>, distance meter <NUM>, projector <NUM>, controller <NUM>, and storage <NUM>. Casing <NUM> includes, for example, resin, but may include metal.

Next, operation device <NUM> will be described. Operation device <NUM> is a remote controller for a user to remotely control projection device <NUM>. Operation device <NUM> is a remote controller exclusive to projection device <NUM>, for example. A mobile terminal such as a smartphone or a tablet terminal in which an exclusive application program is installed may be used as operation device <NUM>. Specifically, operation device <NUM> includes operation receiver <NUM>, communicator <NUM>, controller <NUM>, storage <NUM>, and display <NUM>.

Operation receiver <NUM> is a user interface device that receives an operation performed by a user. Operation receiver <NUM> is implemented by, for example, a hardware button, but may be implemented by a touch panel.

Communicator <NUM> is a communication circuit (in other words, a communication module) for operation device <NUM> to communicate with projection device <NUM>. Communicator <NUM> performs wireless communication with projection device <NUM>, but may perform wired communication with projection device <NUM>. A communication standard for communication performed by communicator <NUM> is not particularly limited.

Controller <NUM> causes communicator <NUM> to transmit, to projection device <NUM>, an instruction signal for causing projection device <NUM> to operate according to an operation received by operation receiver <NUM>. Controller <NUM> is implemented by, for example, a microcomputer or a processor.

Storage <NUM> is a storage device that stores a control program to be executed by controller <NUM>. Storage <NUM> is implemented by, for example, a semiconductor memory. Storage <NUM> also stores architectural design data.

Architectural design data is three-dimensional data (more specifically, a three-dimensional CAD data) indicating the size and shape of space <NUM>. Architectural design data also includes drawing data (two-dimensional data) indicating a floor plan of space <NUM>, and drawing data indicating a marking position. Note that at least drawing data included in architectural design data is also stored in storage <NUM> of projection device <NUM>.

Display <NUM> displays a screen showing, for example, operation conditions of projection device <NUM>. Display <NUM> is implemented by, for example, a liquid crystal panel, or an organic electroluminescent (EL) panel.

In order to accurately project drawing data, it is important to form an association between a position in the drawing data and a position in projection plane <NUM>. Operation example <NUM> of operation performed by projection system <NUM> which includes a process of forming such an association will be described. <FIG> is a flowchart illustrating operation example <NUM> of operation performed by projection system <NUM>.

Note that, in the following description of operation example <NUM>, coordinate axes of orthogonal coordinates are set in space <NUM> as illustrated in <FIG> is a diagram illustrating coordinate axes of orthogonal coordinates in space <NUM>. The coordinate axes illustrated in <FIG> are determined by plotting, as origin O, the position of projection device <NUM> (more specifically, a predetermined position around distance meter <NUM> and projector <NUM> in projection device <NUM>).

Moreover, in the following description of operation example <NUM>, projection plane <NUM> is a floor surface, and two reference lines L1 and L2 are drawn on the floor surface. The two reference lines L1 and L2 are drawn by, for example, a user. The two references lines L1 and L2 are orthogonal to each other. The position of an intersection point of the two reference lines L1 and L2 is reference point D. Reference point D is a point onto which a predetermined point in drawing data is to be projected. Note that positions of reference lines L1 and L2 are specified in drawing data. Accordingly, reference lines L1 and L2 can be used for forming an association between a position in the drawing data and a position in projection plane <NUM>.

First, a user provides projection device <NUM> in space <NUM>, and measures a distance from each of three distance measurement target points (hereinafter, also referred to as measurement points) on projection plane <NUM> to projection device <NUM> (S11). Note that the user is to measure a distance from each of at least three distance measurement target points to projection device <NUM>. The user may measure a distance from each of three or more distance measurement target points to projection device <NUM>.

For example, distance meter <NUM> of projection device <NUM> uses a laser pointer to present a measurement point on projection plane <NUM> to the user. The user drives driver <NUM> to move the laser pointer over reference line L1 (or reference line L2), and performs, in the current state, a measurement instruction operation instructing measurement (storage) of the distance. Then, the distance from a measurement point to projection device <NUM> is stored in storage <NUM>, together with the pan angle ϕ and the tilt angle θ at the time at which the measurement instruction operation is instructed. Note that the pan angle ϕ and the tilt angle θ are measured by angle measurer <NUM>. By the user repeatedly performing such an operation for three times, distance r from each of three mutually different measurement points on projection plane <NUM> to projection device <NUM>, and pan angles ϕ and tilt angles θ at the time at which the distances r are measured are stored in storage <NUM>.

Next, controller <NUM> calculates orthogonal coordinates (xyz coordinates) of the three measurement points, based on the stored information (i.e., results of the distance measurement) (S12). Distance r from each of the three measurement points to projection device <NUM>, and, pan angles ϕ and tilt angles θ at the time at which the distances r are measured, which are stored in storage <NUM>, represent polar coordinates of the three measurement points. Controller <NUM> can convert these polar coordinates into orthogonal coordinates (xyz coordinates) based on the following Math. <NUM>] <MAT>.

Next, controller <NUM> calculates orthogonal coordinates of reference point D, based on the orthogonal coordinates of the three measurement points (S13). As illustrated in <FIG>, when the three measurement points are measurement point A, measurement point B, and measurement point C, controller <NUM> can calculate coordinates of reference point D based on an equation for an orthogonal projection vector shown in <FIG> is a diagram illustrating an equation for an orthogonal projection vector. Note that, when one of measurement point A, measurement point B, and measurement point C is the same point as reference point D, a process of step S13 will be omitted.

Next, controller <NUM> calculates a distance from projection device <NUM> to projection plane <NUM> (i.e., a plane that passes through measurement point A, measurement point B, and measurement point C), and the inclination angle of projection plane <NUM> relative to projection device <NUM> (S14). The following Math. <NUM> (determinant) holds when an equation of projection plane <NUM> is ax + by + cz = d, where coordinates of measurement point A is (xa, ya, za), coordinates of measurement point B is (xb, yb, zb), and coordinates of measurement point C is (xc, yc, zc). Controller <NUM> calculates normal vector n = (a, b, c) of projection plane <NUM> by modifying Math. <NUM> like Math. Normal vector n indicates the inclination angle of projection plane <NUM> in the orthogonal coordinates, and the length of normal vector n indicates the distance from projection device <NUM> to projection plane <NUM>. That is, the calculation of a normal vector is equivalent to the calculation of a distance from projection device <NUM> to projection plane <NUM> and the inclination angle of projection plane <NUM> relative to projection device <NUM>.

Next, controller <NUM> causes projector <NUM> to project drawing data onto projection plane <NUM>, based on the calculated distance from projection device <NUM> to projection plane <NUM> and the calculated inclination angle of projection plane <NUM> (S15). Specifically, controller <NUM> corrects distortion of the drawing data according to the calculated inclination angle of projection plane <NUM>, and corrects a projection scaling factor for the drawing data, based on the calculated distance to projection plane <NUM>.

In addition, the drawing data includes position information of the reference lines. Then, controller <NUM> causes projector <NUM> to project the corrected drawing data onto projection plane <NUM> such that reference lines L1 and L2 in the corrected drawing data overlap reference lines L1 and L2 of the projection plane, and that a predetermined point of the corrected drawing data overlaps the calculated coordinates of reference point D (i.e., determination of projection position). With this, the drawing data is projected onto projection plane <NUM> in actual size.

As has been described, projection system <NUM> uses points on reference lines L1 and L2 of a projection plane which are specified in drawing data as measurement points (points whose coordinates are identified). Therefore, projection system <NUM> can readily form an association between a position in drawing data and a position in projection plane <NUM>.

In the above-described operation example <NUM>, the two straight lines are the two reference lines L1 and L2 orthogonal to each other which are drawn on projection plane <NUM> in advance as marks. However, not falling under the claimed invention, a case in which reference lines L1 and L2 are not drawn can be assumed. <FIG> is a diagram illustrating space <NUM> in which reference lines L1 and L2 are not drawn on projection plane <NUM>.

In the example shown in <FIG>, two beams are disposed on projection plane <NUM> such that the two beams intersect with each other, for example. Reference point D is an intersection point of center lines indicating the center positions of the beams. These center lines are imaginary lines not drawn on projection plane <NUM>, but the positions of the center lines are specified in drawing data.

When reference lines L1 and L2 are not drawn on projection plane <NUM> as described above, projection device <NUM> may indirectly measure a distance to measurement point E on a center line.

For example, distance meter <NUM> of projection device <NUM> uses a laser pointer to present a measurement target point on projection plane <NUM> to a user. The user drives driver <NUM> to move the laser pointer over an edge (e.g., measurement point E1) of a beam, and performs, in the current state, a measurement instruction operation instructing measurement (storage) of the distance. Then, the distance from measurement point E1 to projection device <NUM> is stored in storage <NUM>, together with the pan angle ϕ and the tilt angle θ at the time at which the measurement instruction operation is instructed.

Similarly, the user drives driver <NUM> to move the laser pointer over the other edge (e.g., measurement point E2) of the beam, and performs, in the current state, a measurement instruction operation instructing measurement (storage) of the distance. Then, the distance from measurement point E2 to projection device <NUM> is stored in storage <NUM>, together with the pan angle ϕ and the tilt angle θ at the time at which the measurement instruction operation is instructed.

Thereafter, controller <NUM> (or distance meter <NUM>) calculates polar coordinates of the midpoint between polar coordinates of measurement point E1 and polar coordinates of measurement point E2 as polar coordinates of measurement point E.

As has been described above, a distance from measurement point E on the center line to projection device <NUM> may be indirectly measured by distance meter <NUM> measuring a distance from each of measurement point E1 on an edge of a beam and measurement point E2 on the other edge of the beam to projection device <NUM>, and controller <NUM> calculating the distance to the point on the center line based on the measured distances. Note that a beam is an example of a structure. A distance from a point on the center line of other structures excepting a beam to projection device <NUM> may be indirectly measured.

Since projection system <NUM> as has been described above uses a point on a center line whose position is specified in drawing data as a measurement point (a point whose coordinates are identified), projection system <NUM> can readily form an association between a position in drawing data and a position in projection plane <NUM>.

When moving the laser pointer of distance meter <NUM> over a point on reference lines L1 and L2 (in other words, when a user selects a distance measurement target point), an orientation of distance meter <NUM> is changed by driver <NUM>. In this case, distance meter <NUM> may continuously measure a distance to a distance measurement target point, and controller <NUM> may change a rotation driving speed of driver <NUM> according to the distance measured by distance meter <NUM>. That is, a speed at which an orientation of projection device <NUM> is changed by driver <NUM> may vary depending on a distance from a selected distance measurement target point to projection device <NUM>. <FIG> are diagrams for describing a change in a driving speed of driver <NUM>.

As illustrated in <FIG>, when the distance measured by distance meter <NUM> is distance r1, the driving speed of driver <NUM> is v1. In contrast, when the distance measured by distance meter <NUM> is distance r2 that is longer than distance r1 as illustrated in <FIG>, the driving speed of driver <NUM> is v2 that is slower than v1. As described, controller <NUM> drives driver <NUM> at a slower speed for a longer distance, which is measured by distance meter <NUM>. In other words, controller <NUM> reduces the speed at which an orientation of distance meter <NUM> is changed as the distance measured by distance meter <NUM> increases. Note that although the driving speed at which second driver 26b is driven in a pan direction is denoted by an arrow as an example in <FIG>, the driving speed at which first driver 26a is driven in a tilt direction is also changed in the same manner.

With this, since a measurement position is hardly changed when a distance measured by distance meter <NUM> is long, an operation for a user to move a laser pointer is facilitated.

Since space <NUM> in a huge building is large, a user needs to repeatedly perform operation of changing the position of projection device <NUM> and projecting a drawing data in space <NUM>. When a number of places having similar structure are present in space <NUM>, it may be difficult to form an association between a position in a drawing data and a position in projection plane <NUM> only by performing operation described in operation example <NUM>. For example, there may be a case where massive calculations need to be performed in order to form accurate associations.

In such case, operation locations (e.g., positions of measurement target reference lines L1 and L2) may be designated by a user for projection device <NUM> by inputting operation locations into operation device <NUM>. <FIG> is a flowchart illustrating operation for receiving designation operation for designating reference lines.

As illustrated in <FIG>, display <NUM> of operation device <NUM> displays drawing data (S21), and operation receiver <NUM> receives designation operation for designating reference lines in the displayed drawing data (S22). Controller <NUM> causes communicator <NUM> to transmit a result of the designation to projection device <NUM> (S23). Once the user designates which parts of the displayed drawing data correspond to measurement target reference lines L1 and L2, projection device <NUM> can readily form associations between positions in the drawing data and positions in projection plane <NUM> by projection device <NUM> recognizing the reference lines in the drawing data.

As has been described above, three measurement points are selected by a user using, for example, the laser pointer function of distance meter <NUM>. For this reason, these points may be misaligned with reference lines drawn on projection plane <NUM>. Thus, after the user selecting three measurement points, a confirmation image showing the positions of the selected three measurement points may be projected. <FIG> is a diagram illustrating an example of such confirmation image. <FIG> illustrates a diagram showing reference lines L1 and L2 drawn on projection plane <NUM> and a confirmation image which are viewed from a direction perpendicular to projection plane <NUM>.

As illustrated in <FIG>, confirmation image I is an L-shaped line determined by three measurement points (an L-shaped line that passes through the three measurement points), and is projected by projector <NUM>. That is, the confirmation image is an image of two intersecting line segments. Note that confirmation image I is to be an image showing positions of three measurement points. For example, confirmation image I may show three dots that directly indicate the positions of the three measurement points. Confirmation image I may be any image so long as it shows positions of three measurement points.

As illustrated in (a) of <FIG>, a user can readily recognize the misalignment between the three measurement points and reference lines L1 and L2 according to confirmation image I.

Here, when the three measurement points and reference lines L1 and L2 are misaligned as illustrated in (a) of <FIG>, distances to the three measurement points may be remeasured once again (in other words, the three measurement points may be reselected). Alternatively, controller <NUM> may adjust the projection position of confirmation image I such that positions of the two line segments shown by confirmation image I are projected over the two reference lines, and may correct the projection position of drawing data according to a result of the adjustment.

For example, controller <NUM> finely adjusts the projection position of confirmation image I each time operation receiver <NUM> of operation device <NUM> receives an adjustment operation from a user. When a confirmation image overlaps reference lines L1 and L2 as illustrated in (b) of <FIG> as a result of repeated fine adjustments, operation receiver <NUM> receives an adjustment completion operation from the user. Controller <NUM> stores an amount of adjustment which is added up from the start of the adjustment to the end of the adjustment in storage <NUM>, and cause projector <NUM> to project drawing data with consideration given to the amount of adjustment. With this, a user can project drawing data onto projection plane <NUM>, without remeasuring distances to three measurement points.

As has been described above, a projection method, which is executed by projection device <NUM>, for projecting drawing data for a building onto a projection plane of the building under construction includes: measuring a distance from each of three or more points which are not aligned in a straight line and are on either of two non-parallel straight lines on projection plane <NUM> to projection device <NUM> using distance meter <NUM> included in projection device <NUM> (S11); measuring an angle (e.g., a pan angle and a tilt angle) of distance meter <NUM> at a time at which the distance is measured; and projecting the drawing data onto a projection position on projection plane <NUM> which is determined based on the distance measured and the angle of distance meter <NUM> at the time at which the distance is measured (S15).

Such a projection method as described above can readily form an association between a position in drawing data and a position in projection plane <NUM> by using points on reference lines L1 and L2 of the projection plane as measurement points (points whose coordinates are identified), when the positions of two lines in the drawing data are specified.

In addition, the projection position is determined such that an intersection point of the two straight lines overlaps a predetermined point of the drawing data.

Such a projection method as described above can readily form an association between a position in a drawing data and a position in projection plane <NUM> by using the position of an intersection point of two straight lines.

In addition, the projection method further includes calculating a distance from projection device <NUM> to projection plane <NUM> and an inclination angle of projection plane <NUM>, based on the measured distance and the measured angle of distance meter <NUM> at the time at which the distance is measured (S14). In the projecting (S15), the drawing data on which distortion correction is performed based on the calculated inclination angle of projection plane <NUM> is projected onto the projection position using a projection scaling factor determined based on the calculated distance from projection device <NUM> to projection plane <NUM>.

Such a projection method as described above can project drawing data in actual size.

In addition, the two straight lines are two straight lines orthogonal to each other which are drawn on projection plane <NUM> in advance.

In such a projection method as described above, a user can set measurement points on two straight lines, since the user can visually check the two straight lines.

In addition, in Variation <NUM>, at least one of the two straight lines is a center line indicating a center position of a structure and is an imaginary center line not drawn on projection plane <NUM>, and at least one of the three or more points is positioned on the center line. In the measuring the distance (S11), a distance from each of a point on an edge of the structure and a point on the other edge of the structure to projection device <NUM> is measured, and by calculating a distance to a point on the center line based on the measured distance, a distance from the at least one of the three or more points to projection device <NUM> is indirectly measured.

In such a projection method as described above, a user can set measurement points on two straight lines, even when the user cannot visually check the two straight lines.

In addition, in Variation <NUM>, the projection method further includes driving driver <NUM> included in projection device <NUM> to change an angle of distance meter <NUM> for selecting any of the three or more points as a distance measurement target point (<FIG>). The speed at which the angle of distance meter <NUM> is changed by driver <NUM> varies depending on a distance from the selected distance measurement target point to projection device <NUM>.

According to such a projection method as described above, an operation for a user to set a distance measurement target point is facilitated since a measurement position is hardly changed by reducing the speed at which an angle of distance meter <NUM> is changed as the distance measured by distance meter <NUM> increases.

In addition, in Variation <NUM>, the projection method further includes: displaying the drawing data on display <NUM> (S21); and receiving an operation of a user for designating which parts of the displayed drawing data correspond to the two straight lines (S22).

Such a projection method as described above can readily form an association between a position in a drawing data and a position in projection plane <NUM> by projection device <NUM> recognizing positions of two lines in drawing data which are designated by a user.

In addition, in Variation <NUM>, the projection method further includes projecting confirmation image I indicating positions of the two straight lines ((a) of <FIG>).

According to such a projection method as described above, a user can readily check the positions of two straight lines.

In addition, in Variation <NUM>, confirmation image I is an image of two intersecting line segments.

In addition, in Variation <NUM>, the projection method further includes adjusting a projection position of confirmation image I such that the positions of the two straight lines shown by confirmation image I are over the two reference lines ((b) of <FIG>).

Such a projection method as described above can correct the projection position of drawing data according to a result of adjustment.

In addition, projection device <NUM> includes: projector <NUM> that projects drawing data for a building onto a projection plane of the building under construction; distance meter <NUM> that measures a distance from each of three or more points which are not aligned in a straight line and are on either of two non-parallel straight lines on projection plane <NUM> to projection device <NUM>; angle measurer <NUM> that measures an angle of distance meter <NUM> at a time at which the distance is measured; and controller <NUM> that causes projector <NUM> to project the drawing data onto a projection position on projection plane <NUM> which is determined based on the measured distance and the angle of distance meter <NUM> at the time at which the distance is measured.

Projection device <NUM> as described above can readily form an association between a position in drawing data and a position in projection plane <NUM> by using points on reference lines L1 and L2 of the projection plane as measurement points (points whose coordinates are identified), when the positions of two lines in the drawing data are specified.

In addition, projection system <NUM> includes: projection device <NUM>; and operation device <NUM> for a user to remotely control projection device <NUM>.

Projection system <NUM> as described above can readily form an association between a position in drawing data and a position in projection plane <NUM> by using points on reference lines L1 and L2 of the projection plane as measurement points (points whose coordinates are identified), when the positions of two lines in the drawing data are specified.

The foregoing has described embodiments, yet the present invention is not limited to the above-described embodiments.

For example, although a laser scanning type projection device has been described in the above-described embodiments, the present invention may be implemented by a projector of another type. The projection device is to project at least a part of architectural design data onto a projection plane in actual size.

In addition, the projection system includes a projection device and an operation device in the above-described embodiments. However, the projection system may be implemented as a single device. Moreover, the projection system may be implemented as a client-server system. In this case, a server device performs a part of processing described as performed by the projection device in the above-described embodiments.

In addition, the orders of processes described in the flowcharts of the above-described embodiments are mere examples. The order of processes may be changed, and the processes may be performed in parallel.

In addition, the communication method employed between devices in the above-described embodiments is not particularly limited. Wireless communication or wired communication may be performed between the devices. Moreover, a combination of wireless communication and wired communication may be performed between the devices. In addition, when two devices perform communication in the above-described embodiments, a relay device that is not illustrated may be interposed between the two devices.

Moreover, in the above-described embodiments, each of elements may be implemented by executing a software program suitable for the element. Each element may be implemented by a program execution unit, such as a central processing unit (CPU), processor or the like, loading and executing a software program stored in a storage medium such as a hard disk or a semiconductor memory.

Moreover, each element may be implemented by a hardware product. For example, each element may be a circuit (or an integrated circuit). These circuits may constitute a single circuit as a whole or may be individual circuits. Moreover, these circuits may be general-purpose circuits, or dedicated circuits.

Note that general or specific aspects of the present invention may be implemented by a system, a device, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM. The general or specific aspects of the present invention may also be implemented by an optional combination of a system, a device, a method, an integrated circuit, a computer program, and a recording medium.

For example, the present invention may be implemented as a program for causing a computer to execute the projection method. Alternatively, the present invention may be implemented as a non-transitory computer-readable recording medium on which such a program is recorded.

Claim 1:
A projection method, which is executed by a projection device (<NUM>), for projecting drawing data for a building onto a projection plane (<NUM>) of the building under construction, the projection method comprising: measuring three or more distances, respectively, from three or more points on either of two straight lines (L1, L2) on the projection plane (<NUM>) to the projection device (<NUM>) using a distance meter (<NUM>) included in the projection device (<NUM>, the two straight lines being reference lines orthogonal to each other and drawn on the projection plane (<NUM>) in advance, the three or more points being not aligned in a straight line;
measuring angles of the distance meter (<NUM>) at a time at which the distances are measured, wherein the angles include a pan angle and a tilt angle;
calculating a distance from the projection device (<NUM>) to the projection plane (<NUM>) and an inclination angle of the projection plane (<NUM>) relative to the projection device (<NUM>), based on the distances measured and the angles measured;
correcting distortion of the drawing data based on the calculated inclination angle;
correcting a projection scaling factor for the drawing data based on the calculated distance; and
projecting the drawing data onto a projection position on the projection plane (<NUM>), wherein, in the projecting, the drawing data on which the distortion correction is performed is projected onto the projection position using the corrected projection scaling factor; wherein the projection position is determined based on the distances measured and the angles of the distance meter (<NUM>) at the time at which the distances are measured;
wherein the drawing data includes position information of the two reference lines and the projection position is determined such that i) the two reference lines in the corrected drawing data overlap the two straight lines (L1, L2) on the projection plane (<NUM>), and ii) an intersection point of the two straight lines (L1, L2) overlaps a predetermined point of the corrected drawing data.