Drawing projection system and drawing projection method

Abstract

This invention provides a projection system and projection method that can project drawings with reduced distortion effects onto a construction site. [Solution] The projection system 1 comprises a projection device 2, a reference grid fixture 10, a shooting device 20, and a control unit 60. The control unit 60 includes a grid projection mode 72 in which the projection device projects a reference grid diagram onto the construction site, an image acquisition mode 73 in which the shooting device captures an image of a predetermined grid diagram and reference grid fixture projected by the reference grid diagram from above, a correction processing data creation mode 74 in which correction processing data is created to correct the distortion of the projection based on the reference grid diagram and reference grid fixture in the image acquired in the image acquisition mode, and a drawing projection mode 75 in which the projection device projects a drawing onto the construction site while correcting the distortion of the projection by the projection device based on the correction processing data.

Description

Technical Field

[0001] The present invention relates to a projection system and a projection method, for example, a projection system and a projection method for projecting drawings onto a construction site.

Background Art

[0002] Conventionally, for example, construction work such as newly adding a mobile base station on a building rooftop may be carried out. When attempting to additionally install buildings, structures, equipment, etc. on the rooftop of an existing building, conventionally, based on architectural drawings, paper drawings are compared with the on-site situation to perform operations such as marking with ink. For example, when attempting to install heavy equipment on a building rooftop, since it is necessary to install the equipment on a beam, it is necessary to accurately measure the distance from the target object to identify the installation location, etc. At this time, while referring to the paper drawing, performing scale calculations and confirming the actual measured length and arrangement is cumbersome and requires a number of steps. Also, mistakes are likely to occur. Therefore, there is a demand to simplify the process.

[0003] For example, Patent Document 1 proposes a projection device that projects drawings onto the top surface of a member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when projecting drawings onto a construction site using projection equipment such as a projector placed on a building rooftop, there is a problem: if the projector is not positioned parallel and accurately to the floor surface of the construction site, the drawings will be distorted and not displayed accurately. Adjusting the projector to be properly positioned relative to the floor surface of the construction site is also a complicated and laborious task, as it requires accurately determining the orientation of the projector and understanding the slope of the floor surface.

[0006] Furthermore, construction sites such as building rooftops often have a water-sloping surface for drainage, and because the construction site is not level, there is a challenge in matching the levelness of projection equipment such as projectors with the levelness of the construction site.

[0007] This invention was made to solve these problems and aims to provide a projection system and projection method that can project drawings with reduced distortion effects onto a construction site. [Means for solving the problem]

[0008] To achieve the above objective, according to one embodiment of the present invention, a projection system for projecting a drawing onto a construction site comprises: a projection device for projecting a reference grid diagram onto the construction site; a reference grid fixture arranged on the construction site alongside a predetermined grid diagram obtained by projecting the reference grid diagram; a photographing device for photographing the predetermined grid diagram and the reference grid fixture projected by the projection device from above; and a control unit, wherein the control unit comprises: a grid projection mode for projecting the reference grid diagram onto the construction site using the projection device; an image acquisition mode for acquiring an image of the predetermined grid diagram and the reference grid fixture projected by the reference grid diagram, photographed from above by the photographing device; a correction processing data creation mode for creating correction processing data for correcting projection distortion based on the reference grid diagram and the reference grid fixture in the image acquired by the image acquisition mode; and a drawing projection mode for projecting the drawing onto the construction site using the projection device while correcting projection distortion based on the correction processing data. According to the embodiment of the present invention configured in this manner, the projection distortion of the predetermined grid diagram and the reference grid device in the image acquired in the image acquisition mode can be recognized based on the reference grid diagram and the reference grid device, and correction processing data can be created to calibrate this distortion. Therefore, the projection device can project the drawing onto the construction site while calibrating the distortion of the projection by the projection device. Thus, a drawing with reduced distortion can be projected onto the construction site, contributing to increased efficiency in construction work.

[0009] Preferably, a projection method for projecting a drawing onto a construction site, comprising: a grid projection step of projecting the reference grid diagram onto the construction site using the projection device; an image acquisition step of acquiring an image of the predetermined grid diagram projected by the reference grid diagram and the reference grid fixture arranged on the construction site alongside the predetermined grid diagram, taken from above by the photographing device; a correction processing data creation step of creating correction processing data for correcting projection distortion based on the reference grid diagram and the reference grid fixture in the image acquired in the image acquisition step; and a drawing projection step of projecting the drawing onto the construction site using the projection device while correcting projection distortion by the projection device based on the correction processing data. According to the embodiment of the present invention configured as described above, in the image acquisition step, the predetermined grid diagram and the reference grid device in the image acquired by the image acquisition step can be used to recognize projection distortion based on the reference grid diagram and the reference grid device, and correction processing data can be created to correct this distortion. Therefore, the drawing can be projected onto the construction site by the projection device while correcting the projection distortion by the projection device. Thus, a drawing with reduced distortion can be projected onto the construction site, contributing to increased efficiency in construction work. [Effects of the Invention]

[0010] According to the projection system and projection method of the present invention, drawings with reduced distortion effects can be projected onto the construction site. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram of a projection system according to one embodiment of the present invention. [Figure 2] This is a schematic side view of the imaging device of a projection system according to one embodiment of the present invention. [Figure 3] This is a top view of the reference grid device for a projection system according to one embodiment of the present invention. [Figure 4]This is a schematic diagram of the imaging device of a projection system according to one embodiment of the present invention. [Figure 5] This is a schematic diagram illustrating how drawings are projected onto a construction site using a projection system according to one embodiment of the present invention. [Figure 6] This figure illustrates a reference grid diagram intended for projection by a projection system according to one embodiment of the present invention. [Figure 7] This diagram illustrates a state in which a reference grid diagram is attempted to be projected using a projection system according to one embodiment of the present invention, and in reality, a predetermined grid diagram appears as the projected diagram. [Figure 8] This is a schematic diagram showing the configuration of the control unit of a projection system according to one embodiment of the present invention. [Figure 9] This figure shows a flowchart of a projection method relating to a projection system according to one embodiment of the present invention. [Figure 10] This is a schematic diagram showing a modified example of a projection system according to one embodiment of the present invention. [Modes for carrying out the invention]

[0012] A projection system 1 according to one embodiment of the present invention will be described below with reference to the attached drawings. The embodiments described herein are illustrative and will be apparent to those skilled in the art that many modifications, changes, and substitutions are possible within the spirit and scope of the present invention. Therefore, the present invention is not limited to the embodiments disclosed, and various modifications, changes, etc., are possible in its form and details without departing from the claims. Furthermore, the components disclosed in the specification can be freely combined.

[0013] As shown in FIGS. 1 and 5, a projection system 1 according to an embodiment of the present invention can provide a projection system that projects a projection drawing of a drawing, such as a design drawing, onto a floor F at a construction site. Although an outdoor floor F is shown as an example of the construction site, the construction site may be indoors, and is not limited to a structure, but may also be an outdoor ground or the like. In FIG. 5, an example of the drawing is illustrated as drawing Y. Drawing Y includes drawing information, such as a design drawing or model created by CAD or the like, and a projection drawing created from a model created by CAD or the like. The projection system 1 also functions as a system that supports the construction and building of buildings and structures at the construction site by projecting the drawing onto the floor F. For example, if the projection system 1 arranges the projection device 2 at an approximate position such that the image projected from the projection device 2 is generally projected onto the construction area, it can correct the distortion of the image from the original drawing and project (re-project) a relatively accurate drawing onto the floor F. Although the floor F may be relatively flat, in FIG. 1, an inclined floor surface is illustrated assuming a floor surface with a water gradient.

[0014] The projection system 1 can be applied to various indoor and outdoor construction sites. For example, the projection system 1 can project the drawing in the intended form even when the floor F is sloped, especially on the rooftops of buildings.

[0015] As shown in FIG. 1, the projection system 1 includes a projection device 2, a reference grid device 10, a photographing device 20, and a control unit 60.

[0016] The projection device 2 is formed by a device that projects an image, for example, a so-called projector. The projection device 2 has a function of displaying an image or video by projecting it onto a predetermined area, for example, the floor F. The projection device 2 includes a light source 4, an optical system device 5 that adjusts the light generated by the light source 4, and a lens 6 that projects the light from the optical system device as an image. The projection device 2 is arranged such that if the lens 6 is arranged to be generally parallel to the floor F that forms the floor surface to be projected, an undistorted image is projected and displayed on the floor F. The projection device 2 is arranged, for example, on the pedestal 3. The pedestal 3 is arranged on the floor F and forms a pedestal that rises to a predetermined height. The projection device 2 projects an image within a projection range shown by, for example, a dashed line C (see FIG. 1). The projection device 2 is electrically connected to the control unit 60, receives the output data output from the control unit 60 for image output, and is configured to project a predetermined image instructed by the output data. The projection device 2 is connected to an electrical power supply source such as a power outlet not shown. In reality, the floor F of the facility may have a gradient as shown in FIG. 1. Therefore, arranging the projection device 2 to be parallel to the floor F is a relatively difficult task. The projection device 2 is configured to project a visible light image, for example, an RGB image. As a modification, the projection device 2 may be configured to project an image using only one of the three primary colors of light, for example, only red among red, green, and blue. When the projection device 2 projects a drawing, which is a diagram, by projecting the drawing with only red lines, the occurrence of the chromatic aberration phenomenon can be suppressed, and the drawing can be projected more clearly.

[0017] The projection device 2 is formed to project a reference grid diagram XA for image calibration as described later toward the floor F, and as a result, project a predetermined grid diagram X1 (the reference grid diagram XA if set to not cause distortion) onto the floor F. For example, an ideal predetermined grid diagram is shown in FIG. 6 as the reference grid diagram XA.

[0018] As shown in Figure 1, the reference grid fixture 10 is placed on the floor F alongside a predetermined grid diagram X1. This arrangement includes both cases where the reference grid fixture 10 is placed within the area of ​​the predetermined grid diagram X1 and where it is placed outside the area of ​​the predetermined grid diagram X1. As shown in Figure 3, the reference grid device 10 is formed in a square shape when viewed from above. The reference grid device 10 comprises a spherical corner portion 10a, a straight portion 10b extending between the two corner portions, and an angle gauge 10c. The corners 10a are formed from four corners 10a of a square, forming a spherical connecting portion. The corners 10a are formed to a certain size, for example, a diameter within the range of 5 cm to 20 cm, or for example, a diameter within the range of 5 cm to 10 cm. For example, by forming a spherical connecting portion, when an image is taken by the imaging device 20, it becomes easier to compare the size of the spherical connecting portion of the reference grid device 10 with the size of a specific part in the captured image. Also, by making the connecting portion spherical, it becomes easier to estimate the position of the center of gravity. Furthermore, by making the corners 10a a certain size, it becomes easier to recognize and use the corners 10a as a reference from above. In addition, the corners 10a are painted black to make them easily recognizable.

[0019] The straight section 10b forms a rod-shaped member. The straight section 10b is inserted into and fixed in the mounting hole of the spherical corner section 10a. The straight section 10b is formed to have a length, for example, within the range of 50 cm to 100 cm, or a length, for example, within the range of 40 cm to 150 cm. The straight section 10b is formed such that the distance from the center of one corner section 10a along the straight section 10b to the center of another corner section 10a is, for example, 100 cm. Therefore, the straight section 10b functions as a member that provides a reference length. Each side (10b1, 10b2, 10b3, 10b4) that constitutes the square all similarly functions as a member that defines a reference length. Therefore, the vertical and horizontal distortions of the projected predetermined grid diagram can be compared and calibrated in both the vertical and horizontal directions. In addition, adjacent straight sections 10b form a 90-degree angle. The lengths of the corners 10a and straight sections 10b of the reference grid device 10 may be set to match the lengths of the grids (the length of each individual grid) in the projected predetermined grid diagram X1. In this case, the accuracy and efficiency of the comparison between the two are further improved. The reference grid device 10 is equipped with an angle meter 10c in the straight section 10b between the corners 10a to measure the gradient at that position. The angle meter 10c is provided, for example, in the middle of the straight section 10b. Therefore, the angle meter 10c can measure the gradient of the floor surface (ground) F. By measuring the gradient of the floor surface with the angle meter 10c in the middle of the straight section 10b, the grid can be calibrated after recognizing the gradient, even when the floor surface of a building rooftop has a slope such as a water slope. In addition, by placing the angle meter 10c in the middle of the straight section 10b, the average gradient between two corners 10a can be measured. The reference grid device 10 is configured as a square grid-shaped device with corner sections 10a, straight sections 10b, and angle gauges 10c. As an alternative, the angle gauge 10c may be placed in the corner 10a. Since the corner 10a is spherical and of a certain size, the angle gauge 10c can be easily placed in the corner 10a, making it easier to form the reference grid device 10.

[0020] In this embodiment, the reference grid device 10 forms a single quadrilateral grid with corners 10a and straight sections 10b, but the number of grids can be changed to any number. For example, the number of grids can be 2, 4, 8, 9, etc. By increasing the number of grids and arranging them in a row, the number of corners 10a and straight sections 10b that serve as references for length and position increases, thereby improving the accuracy of calibration. In addition, calculations can be performed more easily.

[0021] As shown in Figure 1, the imaging device 20 is configured to photograph the predetermined grid diagram X1 and the reference grid device 10 projected by the projection device 2 from above. The imaging device 20 comprises a drone 22, a camera 24 mounted on the drone 22, an altitude measuring device 25 for measuring the altitude of the aircraft from the floor, a GPS device 26, a drone-side communication unit 27, and a drone-side control unit 28. Because the imaging device 20 includes a drone 22, the construction site can be photographed from above relatively easily. Furthermore, the drone's coordinates, position, and altitude can be changed for photography. In addition, even when the construction site is relatively large, the drone 22 can be raised for photography.

[0022] As shown in Figure 1, the drone 22 is an unmanned aerial vehicle, such as a multi-rotor drone, but it may be of other forms. The drone 22 comprises a main body 22a and four arms extending outward from the main body 22a, each equipped with a rotor 22b and blades (rotating wings) 22c for rotating the blades. By controlling the rotation speed of each blade 22c, the drone 22 is configured to move in the forward, backward, left, right, and up and down directions. In this embodiment, the drone 22 has four arms and one blade installed on each arm (a total of four blades), but this may be changed to a different number of arms and blades installed on each arm. The control unit 60 allows the drone 22 to fly along a predetermined position, altitude, and course, and to perform takeoffs and landings fully automatically according to a predetermined program. Thus, the drone 22 can fly from the floor F to above the area of ​​a predetermined grid diagram X1 that is projected, photograph the area of ​​the predetermined grid diagram X1, and return to a return point, for example, the same point as the departure point. The drone 22 may be replaced with other types of flying objects capable of flying at any location, such as a helicopter.

[0023] As shown in Figure 4, the camera 24 is mounted on the main body 22a of the drone 22, allowing the drone 22 to photograph and view the projection area of ​​the drawing. The camera 24 has the capability to shoot videos and still photographs. The camera 24 can acquire the shape of a predetermined grid diagram X1 as an image, as well as the shape of the reference grid device 10 as an image. The camera 24 is a camera capable of capturing visible light images, such as an RGB camera. The camera 24 can capture images within the range shown by the dashed line D in Figure 1, for example.

[0024] The altitude measuring device 25 is installed on the aircraft body 6a and can measure the altitude H (distance) of the drone 22 relative to the ground G where landmines M may be buried. The altitude measuring device 25 uses, for example, an ultrasonic altimeter that can measure the height to the ground G. The altitude measuring device 25 may be composed of any or any combination thereof of a barometric pressure sensor that can measure the flight altitude by measuring the atmospheric pressure, an ultrasonic sonar that can measure the distance from the drone 22 to the ground G, a laser measuring sensor that can measure the distance from the drone 22 to the ground G, or a LIDAR sensor that can measure the distance from the drone 22 to the ground G. As a result, the altitude measuring device 25 can measure the altitude H (distance) from the drone 22 to the floor F, which is the construction site. For example, the altitude measuring device 25 can measure the altitude (distance) H within a predetermined range of 2m to 10m from the drone 22 to the floor F, more preferably within a range of 2m to 5m. For example, when the drone 22 is at an altitude of 3m, the area onto which the predetermined grid diagram X1 is projected can be an area with values ​​within a range of, for example, 5m vertically x 5m horizontally.

[0025] The GPS device 26 is capable of determining the current location information of the drone 22 (for example, information such as latitude and longitude) using satellites. Furthermore, the GPS device 26 can recognize the position of the drone 22 and provide the position information necessary for predetermined flight control of the drone 22.

[0026] As shown by the dashed line B in Figure 1, the drone-side communication unit 27 is electrically connected to the control unit 60 and can wirelessly transmit data from the drone 22. For example, the drone-side communication unit 27 can transmit image information captured by the camera 24 to the control unit 60. The drone-side communication unit 27 may also receive command signals from the control unit 60.

[0027] The drone 22 may be equipped with a manual control unit 70, a monitor 71, etc., as needed.

[0028] The drone-side control unit 28 incorporates a CPU 29 and a storage device 31 such as memory, and controls connected devices to execute predetermined controls based on a predetermined control program recorded in the memory, etc. The drone-side control unit 28 is electrically connected to the drone 22, camera 24, altitude measuring device 25, GPS device 26, drone-side communication unit 27, operation unit 70, monitor 71, etc. These electrical connections may be made by wireless communication or the like.

[0029] The drone-side control unit 28 can perform flight control of the drone 22. The drone-side control unit 28 is configured to perform predetermined functions in cooperation with the control unit 60. Together with the control unit 60, the drone-side control unit 28 can control each device mounted on the drone 22 and control the flight of the drone 22. More specifically, the drone-side control unit 28 can control the position (coordinates, altitude) where the camera 24 photographs a predetermined grid diagram X1 and a reference grid device 10, attitude control during photography, rotation suppression control in the yawing direction, movement between the departure point and the photography point, etc. In this way, the drone-side control unit 28 can control the flight altitude of the drone 22, the flight route, the rotation speed of each blade, attitude (including left and right roll and yawing in the rotation direction, etc.), and, if necessary, the operation control of the camera 24, etc. The drone-side control unit 28 can make the drone 22 reach a predetermined altitude above the predetermined grid diagram X1 and the reference grid device 10, and enable photography control by the camera 24. The drone-side control unit 28 may be provided as an integral part of the control unit 60. For example, all or part of the functions of the drone-side control unit 28 may be provided on the control unit 60 side. All or part of the functions of the drone-side control unit 28 may be provided on the information terminal equipment, etc., on the operation unit 70 side. Thus, the drone 22 may be equipped with a manual operation unit 70, a monitor 71 for the operation unit 70, etc., as needed. The projection system 1 may be controlled entirely or partially manually by the manual operation unit 70.

[0030] The control unit 60 is electrically connected to the projection device 2 and the imaging device 20. The control unit 60 is configured to perform image projection by the projection device 2, image capture by the imaging device 20, and analysis of images captured by the imaging device 20. The control unit 60 is provided in a computer connected to the projection device 2, etc. As shown in Figure 3, the control unit 60 is electrically connected to the drone 22 via the internet. The control unit 60 may also be provided in an electronic device that functions as a computer, such as a smartphone or tablet. As shown in Figure 4, the control unit 60 has a CPU 63 and a storage device 65 such as memory, and controls the connected devices based on a predetermined control program recorded in the memory, etc. Therefore, the control unit 60 functions as a computer. The electrical connection between the control unit 60 and other devices may be entirely or partially connected by wireless communication such as infrared communication or other methods. The control unit 60 has a predetermined program for performing predetermined control functions. The control unit 60 may also be composed of multiple devices. The storage device 65 of the control unit 60 stores a predetermined program, but it does not necessarily have to store all of the program; some or all of it may be stored in multiple devices, or on a server via the Internet. For example, the drone-side control unit 28 mounted on the projection system 1 may be configured to execute some or all of the control functions. The control unit 60 is equipped with output devices 62 such as monitors and input devices 64 that can be operated, and various modes can be set.

[0031] The control unit 60 also stores data for the reference grid diagram XA. The control unit 60 knows the exact dimensions, size, and shape of the reference grid diagram XA. The control unit 60 can use the reference grid diagram XA as a reference that can be used to recognize distortion caused by projection from the projection device 2, as described later. The reference grid diagram XA is a grid that serves as a constant reference. If the projection device 2 is installed in an ideal state in which it can accurately project an image onto the floor F, the projection device 2 will attempt to project (output) the reference grid diagram XA, and the reference grid diagram XA will be projected onto the floor F. On the other hand, if the projection device 2 is not installed in an ideal state in which it can accurately project an image onto the floor F, for example, if the projection device 2 is simply placed without adjusting for image distortion, the projection device 2 will attempt to project (output) the reference grid diagram XA, and a predetermined grid diagram X1 will be projected onto the floor F. The reference grid diagram XA is a diagram of a grid made up of squares, and for example, the length of one side XAa of each square is 1m. Side XAa also has a length that is, for example, within the range of 0.5m to 2m. The length of side XAa can be changed to any length. Each side of the reference grid diagram XA forms a 90-degree angle. In the example shown in Figure 6, the reference grid diagram XA forms a grid size that covers an area of ​​4m x 4m. The size of the reference grid diagram XA can be changed arbitrarily; for example, it may be formed with a total of 9 grids (3x3) to cover an area of ​​3m x 3m to suit the object to be constructed. Alternatively, the reference grid diagram XA may be formed with a total of 25 grids (5x5) to cover an area of ​​5m x 5m.

[0032] As shown in Figure 8, the control unit 60 includes a grid projection mode 72 in which the projection device 2 projects a predetermined grid diagram X1 onto the floor F; an image acquisition mode 73 in which the imaging device 20 captures an image of the predetermined grid diagram X1 and reference grid fixture 10 projected by the grid projection mode 72 from above; a correction processing data creation mode 74 in which correction processing data is created for correcting the distortion of the projection of the predetermined grid diagram X1 and reference grid fixture 10 in the image acquired by the image acquisition mode 73 based on the reference grid diagram and reference grid fixture; and a drawing projection mode 75 in which the projection device 2 projects a drawing onto the floor F while correcting the distortion of the projection by the projection device 2 based on the correction processing data. According to the correction processing data creation mode 74 and the drawing projection mode 75, a drawing that is appropriate to the conditions of the floor F can be projected onto the floor F relatively accurately with the current placement of the projection device 2. The drawing projection mode 75 includes a switching mode 76 that switches between output formats for drawings that are adjusted to a slope and drawings that are adjusted to a horizontal plane. The control unit 60 includes a re-grid projection mode 77 that, based on correction processing data, causes the projection device 2 to project a predetermined grid diagram X1 onto the floor F while calibrating the distortion of the projection by the projection device 2, and confirms that the predetermined grid diagram X1 has been calibrated. With the re-grid projection mode 77, even when calibrating the distortion of the projection by the projection device 2 based on correction processing data, the predetermined grid diagram X1 is projected again by the projection device 2, making it easy to confirm whether the correction processing data is functioning well in calibrating the distortion of the projection.

[0033] The control unit 60 creates correction processing data for correcting projection distortion based on the reference grid diagram and reference grid device 10 in the image acquired in the correction processing data creation mode 74. The mechanism for creating the correction processing data is, for example, to acquire the coordinates of the grid intersections of the captured predetermined grid diagram X1. For example, the coordinates of all grid intersections are acquired. The intersections of the grid in the reference grid diagram XA corresponding to the intersections for which the coordinates have been acquired are recognized, and the coordinates of each intersection are acquired. As a result, the correction processing data includes a function to move the coordinates of the intersections in the predetermined grid diagram X1 to the coordinates of the intersections in the reference grid diagram XA. The correction processing data includes a correction program that includes commands to execute the correction processing. Furthermore, the correction processing data can also function as correction processing data that makes the distance between intersections in the predetermined grid diagram X1 smaller than the distance between intersections in the reference grid diagram XA. With such a mechanism, accuracy can also be improved by making the grid fineness of the reference grid diagram XA finer to a certain extent. Such correction processing data (correction program) has the function of correcting a distorted drawing, such as a predetermined grid diagram X1, into a correct drawing, such as a reference grid diagram XA. Furthermore, it has the function of using this distortion correction in reverse to create data (correction processing data) to be projected from the projection device 2, assuming that the same distortion will be applied when there is a request to actually project a correct drawing, such as a reference grid diagram XA. By preparing correction processing data for distorted drawings (grids) in advance based on a certain theory, distortion caused by the projection device, etc., can be applied, and a correct drawing, such as a reference grid diagram XA, can be actually projected. As another variation, a different mechanism for creating correction processing data is to check, for example, whether the lines connecting the intersections of the grid in a predetermined grid diagram X1 are straight lines. If the lines connecting the intersections are curved instead of straight, the correction processing data is created to correct them into straight lines. The correction processing data includes a correction program that includes commands to execute the correction process. The correction processing data can also function as correction processing data that corrects the curved parts of the straight lines between intersections in the predetermined grid diagram X1 to match the straight lines between intersections in a reference grid diagram XA. With such a mechanism, accuracy can also be improved by making the grid finer in the reference grid diagram XA to a certain degree. Such correction processing data (correction program) has the function of correcting a distorted drawing like the predetermined grid diagram X1 into a correct drawing like the reference grid diagram XA, and also has the function of using this distortion correction in reverse to create data (correction processing data) to be projected from the projection device 2, assuming that the same distortion will be applied when there is a request to actually project a correct drawing like the reference grid diagram XA. By preparing correction data for distorted drawings (grids) in advance based on a certain theory, distortions caused by projection devices are applied, and a correct drawing, like the reference grid diagram XA, can be projected.

[0034] The control unit 60 has a switching mode 76 that allows it to switch between two functions when projecting by the projection device 2: one that projects the intended drawing onto the construction site assuming the site is level, and another that projects a corresponding drawing onto the construction site in order to construct the intended structure on a virtual horizontal plane when the construction site is sloped. The corresponding drawing is a drawing that takes the slope into account, and for example, its dimensions will be longer than those of the actual intended drawing. Thus, the corresponding drawing projected onto a construction site with a slope may appear distorted compared to the intended drawing itself because it takes the slope into account. Therefore, the control unit 60 can relatively easily switch and display between the function of simply projecting the intended drawing assuming the construction site is level and the function of projecting a corresponding drawing that takes the slope into account when the construction site is sloped, using the switching mode 76.

[0035] Next, with reference to Figure 9, a projection method for projecting a drawing onto the floor using projection system 1 will be described. In step S1, a projection system 1 is prepared, comprising a projection device 2, a reference grid device 10, a shooting device 20, and a control unit 60. The drone 22 of the shooting device 20 is stationary, for example, on the floor F. When step S1 is completed, the control unit 60 proceeds to S2.

[0036] In step S2, the control unit 60 attempts to project the reference grid diagram XA onto the floor F using the projection device 2, and as a result, executes a grid projection step in which a predetermined grid diagram X1 is projected onto the floor F. The control unit 60 causes the projection device 2 to project the reference grid diagram XA onto the floor F so that an ideal reference grid diagram XA (see Figure 6) can be projected if the projection device 2 is in an ideal position (the projection device 2 is horizontal and oriented appropriately relative to the floor F) and the floor F is in an ideal state (level and without slopes or irregularities). However, if the projection device 2 is in an inclined position from the ideal position, or if the floor F has a slope, the state in which the reference grid diagram XA is projected onto the floor F becomes a predetermined grid diagram X1 (see Figure 7). In many cases, if the worker simply places the projection device 2 on some kind of base, such as a tripod or other support legs, above the floor F of the construction site, the figure projected from the projection device 2 is a predetermined grid diagram X1 that contains some distortion compared to the original data and the final projection target, which is the reference grid diagram XA. If projection device 2 is installed in an ideal state, the reference grid diagram XA will be displayed. According to this technology, the effort required to adjust the projection device 2 to an ideal configuration (ideal setting) to project an image ideally is eliminated. By simply arranging the projection device 2 in a relatively simple manner, the predetermined grid diagram X1 can be adjusted (calibrated) and the reference grid diagram XA can be displayed. In other words, it has the advantage of being able to display the intended drawing while reducing distortion. When step S2 is completed, the control unit 60 proceeds to S3.

[0037] In step S3, the control unit 60 executes an image acquisition step in which the imaging device 20 captures an image of the predetermined grid diagram X1 and the reference grid device 10 projected in the grid projection step S2 from above. The control unit 60 takes off the imaging device 20 from an initial position, for example, the floor F, and photographs both the predetermined grid diagram X1 and the reference grid device 10 from a predetermined altitude H above the predetermined grid diagram X1. Thus, the imaging device 20 can acquire an image of how the predetermined grid diagram X1 is projected (appears) relative to the reference grid diagram XA, and further, how the predetermined grid diagram X1 appears relative to the reference grid device 10 whose dimensions are known in advance. The reference grid device 10 in the image may also have changed relative to the correct reference grid device 10. The control unit 60 can make the drone 22 fly fully automatically along a predetermined course according to a predetermined program. When step S3 is completed, the control unit 60 proceeds to S4.

[0038] In step S4, the control unit 60 executes a correction processing data creation step to create correction processing data for calibrating projection distortion from the predetermined grid diagram X1 and the reference grid device 10 captured in the shooting step S3. The control unit 60 acquires the image data captured in the image acquisition step S3 via the drone-side communication unit 27 of the drone 22. In the correction processing data creation mode 74, the distortion can be calculated from the state in which the reference grid diagram XA becomes the predetermined grid diagram X1, and correction processing data that has been pre-distorted is created so as to obtain the reference grid diagram XA. The shooting device 20 can acquire images of how the predetermined grid diagram X1 appears with respect to the reference grid diagram XA, and further, how the predetermined grid diagram X1 appears with respect to the reference grid device 10 whose dimensions are known in advance. The control unit 60 can determine from the acquired image data how the predetermined grid diagram X1 is distorted with respect to the reference grid diagram XA, and further, how the predetermined grid diagram X1 is distorted with respect to the reference grid device 10 whose dimensions are known in advance. Therefore, the control unit 60 can determine how the predetermined grid diagram X1 is distorted relative to the reference grid diagram XA, and in the correction processing data creation step S4, it creates pre-distorted correction processing data such that the reference grid diagram XA is projected as a result. That is, when the imaging device 20 projects based on the correction processing data, distortion occurs similarly, and as a result the reference grid diagram XA is projected (appears) on the floor F. The control unit 60 takes similar distortion into consideration and creates correction processing data for the distorted drawing (correction processing data that has undergone pre-processing for projection) so that the actual drawing is projected on the floor F as a result. When step S4 is completed, the control unit 60 proceeds to S5.

[0039] In step S5, the control unit 60 performs a drawing projection step in which the projection device 2 projects a drawing, for example, drawing Y, onto the floor F, while calibrating the distortion of the projection by the projection device 2 based on the correction processing data. When the imaging device 20 projects an image adjusted based on the correction processing data so that the actual intended drawing appears with the intended dimensions, the actual drawing (the drawing intended in a design drawing, for example, drawing Y) is projected onto the floor F in a state that is not distorted in a general manner. In this case, for example, the distortion calibration described above is performed. Alternatively, for example, when the imaging device 20 projects an image in which preprocessing has been performed on the reference grid diagram XA to display the reference grid diagram XA, based on correction processing data based on a predetermined grid diagram X1 (correction processing data for correction when the predetermined grid diagram X1 is displayed when attempting to output the reference grid diagram XA), the reference grid diagram XA is projected onto the floor F in a state that is not distorted in a general manner. In this case as well, the same predetermined distortion calibration is performed. By performing preprocessing adjustments based on the correction data in this manner, the reference grid diagram XA can be displayed with the intended dimensions, and furthermore, the intended drawing can be displayed with the intended dimensions. Those who intend to construct structures, etc., at the construction site can proceed with construction work efficiently based on the displayed drawing. When step S5 is completed, the control unit 60 proceeds to the end.

[0040] The drawing projection step of the control unit 60 may also be performed by executing the switching step according to the switching mode 76. The projection device 2 has a function to switch between a function that projects the intended drawing onto the construction site assuming the construction site is horizontal, and a function that projects a corresponding drawing onto the construction site in order to construct a structure etc. on the intended drawing on a virtual horizontal plane when the construction site is sloped. The corresponding drawing is a drawing that takes the slope into account, and for example, the dimensions will be longer than those of the actual intended drawing. As a result of taking the slope into account, the corresponding drawing projected onto the construction site in this way may appear distorted to the naked eye of a third party compared to the intended drawing itself. With this function, it is possible to project the intended drawing onto the construction site assuming the construction site is horizontal. In addition, it is possible to project a corresponding drawing onto the construction site in order to construct a structure etc. on the intended drawing on a virtual horizontal plane when the construction site is sloped. Therefore, it is possible to project a drawing corresponding to the construction method.

[0041] An example of one embodiment of the present invention may be provided in the following embodiments.

[0042] (1) A projection system for projecting drawings onto a construction site, comprising: a projection device for projecting a reference grid diagram onto the construction site; a reference grid fixture placed on the construction site alongside a predetermined grid diagram obtained by projecting the reference grid diagram; a photographing device for photographing the predetermined grid diagram and the reference grid fixture projected by the projection device from above; and a control unit, wherein the control unit comprises: a grid projection mode for projecting the reference grid diagram onto the construction site using the projection device; an image acquisition mode for acquiring an image of the predetermined grid diagram and the reference grid fixture projected by the reference grid diagram, photographed from above by the photographing device; a correction processing data creation mode for creating correction processing data for correcting projection distortion based on the reference grid diagram and the reference grid fixture in the image acquired by the image acquisition mode; and a drawing projection mode for projecting the drawings onto the construction site using the projection device while correcting projection distortion based on the correction processing data.

[0043] (2) The projection system according to (1), wherein the photographic device comprises a drone, a camera provided on the drone, and an altitude measuring device for measuring the altitude of the drone from the construction site.

[0044] (3) The projection system according to (1), wherein the photographic device comprises a structure extending upward from the construction site above the projection device and a camera provided on the structure.

[0045] (4) The projection system according to (1), wherein the control unit has a re-grid projection mode that allows the projection device to project the predetermined grid diagram onto the construction site while calibrating the distortion of the projection by the projection device based on the correction processing data, and to confirm that the predetermined grid diagram has been calibrated.

[0046] (5) The projection system according to (1), wherein the reference grid device is formed in a square shape when viewed from above, and the straight sections between the corners are equipped with an angle meter for measuring the gradient of the position.

[0047] (6) The projection system according to (1), wherein the reference grid device is formed in a square shape when viewed from above, and is equipped with an angle meter at the corner for measuring the gradient of its position.

[0048] (7) The projection system according to (1), wherein the corners of the reference grid device form spherical connecting parts.

[0049] (8) The projection system according to (1), wherein the drawing projection mode includes a switching mode that switches between a function to simply project a drawing intended for a construction site that is level, and a function to project a corresponding drawing that takes the slope into account for a construction site that is sloped.

[0050] (9) A projection method for projecting a drawing onto a construction site, comprising: a grid projection step of projecting the reference grid diagram onto the construction site using the projection device; an image acquisition step of acquiring an image of the predetermined grid diagram projected by the reference grid diagram and the reference grid fixture arranged on the construction site alongside the predetermined grid diagram, taken from above by the photographing device; a correction processing data creation step of creating correction processing data for correcting projection distortion based on the reference grid diagram and the reference grid fixture in the image acquired by the image acquisition step; and a drawing projection step of projecting the drawing onto the construction site using the projection device while correcting projection distortion by the projection device based on the correction processing data.

[0051] The embodiments for carrying out the present invention are not limited to those described above, and further variations can be applied. Various alternative embodiments and examples will be apparent to those skilled in the art based on the disclosed technology. For example, the shooting device 20 may include a structure 80 extending upward from the floor F of the construction site above the projection device 2, and a camera 82 provided on the structure 80. The structure 80 is, for example, a pole provided on the floor F and can be fixed on the floor F by weights (not shown). The structure 80 can be formed from a rod-shaped member with a length of, for example, 2m to 3m. The camera 82 is provided on the upper part of the structure 80 and can capture and view the projection area of ​​the drawing from the camera 82. The camera 82 has the function of shooting video and taking photographs. The camera 82 can acquire the shape of a predetermined grid diagram X1 as an image, and can also acquire the shape of the reference grid device 10 as an image. The camera 82 is configured as a camera capable of capturing visible light images, for example, an RGB camera. Since the shooting device 20 can be formed from the structure 80 and the camera 82, the shooting device can be formed by relatively simple means, such as placing the camera 82 on top of a pole. This makes it possible to form the shooting device 20 without preparing a drone. Furthermore, even in urban areas and other regions where drone flight permits are required, this eliminates the hassle of applying for drone flight permits, making it relatively easy to assemble a filming device. [Explanation of Symbols]

[0052] 1: Projection System 2: Projection device 10:Reference grid fixture 10a: Corner 10b: Straight section 10c: Angle meter 20: Imaging device 22: Drone 24: Camera 25: Altitude measuring device 60: Control Unit 72: Grid projection mode 73: Image acquisition mode 74: Correction processing data creation mode 75: Drawing projection mode 76: Switching Mode 77: Re-lattice projection mode 80 :Structure 82: Camera

Claims

1. A drawing projection system for projecting drawings onto a construction site, A projection device for projecting a reference grid diagram onto the construction site, A reference grid device is placed at the construction site alongside a predetermined grid diagram obtained by projecting the aforementioned reference grid diagram, A photographing device that photographs the predetermined grid diagram and the reference grid device projected by the projection device from above, It includes a control unit, The control unit, A grid projection mode in which the projection device projects the reference grid diagram onto the construction site, An image acquisition mode in which the predetermined grid diagram and the reference grid device projected by the aforementioned reference grid diagram are captured from above by the imaging device, A correction processing data creation mode for creating correction processing data for correcting projection distortion based on the predetermined grid diagram and the reference grid device in the image acquired by the image acquisition mode, The system includes a drawing projection mode in which the projection device projects the drawing onto the construction site while calibrating the distortion of the projection by the projection device based on the correction processing data, The aforementioned reference grid device is formed in a square shape when viewed from above and has spherical corners, the corners are arranged at the four corners of the square, the corners form connecting parts that connect straight sections extending between the corners, and the corners are formed to have a diameter within the range of 5 cm to 20 cm so that it is easy to compare the size of the spherical corners with a specific part in the captured image, in a drawing projection system.

2. The drawing projection system according to claim 1, wherein the photographic device comprises a drone, a camera provided on the drone, and an altitude measuring device for measuring the altitude of the drone from the construction site.

3. The drawing projection system according to claim 1, wherein the photographic device comprises a structure extending upward from the construction site above the projection device and a camera provided on the structure.

4. The drawing projection system according to claim 1, wherein the control unit includes a re-grid projection mode that, based on the correction processing data, causes the projection device to project the predetermined grid diagram onto the construction site while calibrating the distortion of the projection by the projection device, and confirms that the predetermined grid diagram has been calibrated.

5. The drawing projection system according to claim 1, wherein the reference grid device is formed in a square shape when viewed from above, and is equipped with an angle meter for measuring the gradient in the straight section between the corners.

6. The drawing projection system according to claim 1, wherein the reference grid device is formed in a square shape when viewed from above, and is equipped with an angle meter for measuring the gradient at the corners.

7. The drawing projection system according to claim 1, wherein the drawing projection mode includes a switching mode that switches between a function to simply project a drawing intended for a construction site that is level, and a function to project a corresponding drawing that takes the slope into account when the construction site is sloped.

8. A drawing projection method for projecting drawings onto a construction site using a drawing projection system, The drawing projection system includes a projection device that projects a reference grid diagram onto the construction site, A reference grid device is placed at the construction site alongside a predetermined grid diagram obtained by projecting the aforementioned reference grid diagram, The system comprises a shooting device and a control unit that photographs the predetermined grid diagram and the reference grid device projected by the projection device from above, the reference grid device being formed in a square shape when viewed from above and having spherical corners, the corners being arranged at the four corners of the square, the corners forming connecting parts that connect the straight sections extending between the corners, and the corners being formed to have a diameter within the range of 5 cm to 20 cm so as to facilitate size comparison between the spherical corners and specific parts in the captured image. The aforementioned drawing projection method is, A grid projection step in which the projection device projects the reference grid diagram onto the construction site, Image acquisition step: Obtain an image of the predetermined grid diagram projected by the aforementioned reference grid diagram and the reference grid fixture placed at the construction site alongside the predetermined grid diagram, by photographing it from above with the photographing device. A correction processing data creation step is performed to create correction processing data for correcting projection distortion based on the predetermined grid diagram and the reference grid device in the image captured by the image acquisition step, A drawing projection method comprising: a drawing projection step of projecting the drawing onto the construction site using the projection device while calibrating the distortion of the projection by the projection device based on the correction processing data.

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