Overhead image output device, overhead image display system, and work machine

Abstract

The present invention realizes an overhead image output device for a work machine and a work machine that make it possible to reduce misrecognition of an image boundary part while reducing waste of effective images as much as possible. An overhead image display system (20) comprises a plurality of cameras (21 to 23) mounted on a work machine, a display device (26), and an overhead image output device (240). The overhead image output device comprises: an overhead image generation unit (241) that generates an overhead image on the basis of images captured by the plurality of cameras; a display control unit (242) that causes the display device to display the generated overhead image by superimposing a mask image on an image missing region of the overhead image; and a mask region setting unit (243) that causes the display device to display the overhead image and receives setting of a mask region that is covered by the mask image, with respect to the displayed overhead image.

Description

Bird's-eye view image output device, bird's-eye view image display system, work machine

[0001] The present invention relates to an overhead image output device mounted on a work machine, an overhead image display system, and the work machine.

[0002] BACKGROUND ART Conventionally, there is known a driving assistance system that presents a driver with an overhead image obtained by stitching together images captured by a plurality of cameras mounted on a vehicle that capture images of the surroundings of the vehicle.

[0003] In the field of work machines such as construction machinery, there is known a technique for displaying an overhead image on a display unit in a driver's cab by stitching together images captured by multiple cameras mounted on the work machine (see, for example, Patent Document 1). Generally, in work machines, the multiple cameras are mounted in three locations on the left, right, and rear of the work machine so as to capture images in three directions, i.e., the left, right, and rear of the work machine.

[0004] Japanese Patent Application Publication No. 2019-71677

[0005] However, when capturing images in three directions and displaying an overhead image as in the technology of Patent Document 1, the image of the front part of the overhead image where no camera is installed is missing. The image boundary, which is the boundary between the missing part and the image part, is not a straight line. If the image boundary has an angular part, such as a staircase, a driver viewing the overhead image while operating a work machine may mistake the angular part for an obstacle such as a pillar.

[0006] One possible measure to reduce such misidentification is to place a mask image in the area where the image is missing in the overhead image and use the mask image to cover the missing area, including the image boundary in the overhead image. However, the position of the image boundary varies depending on the mounting positions of multiple cameras. Therefore, to accommodate differences in mounting positions, it is necessary to use a mask image of a size that can encompass these differences. However, in this case, there is a problem that the mask image may hide even parts of the image that would otherwise be effectively displayed without any problems.

[0007] One aspect of the present invention aims to realize an overhead image output device and an overhead image display system for a work machine, and a work machine, which can minimize the waste of useful images while reducing the recognition of image boundary portions.

[0008] In order to solve the above problems, an overhead image output device according to one aspect of the present invention is an overhead image output device mounted on a work machine, and includes: an overhead image generation unit that generates an overhead image of the area around the work machine based on images captured by a plurality of cameras mounted on the work machine; a display control unit that displays the generated overhead image on a display device by superimposing a mask image on missing areas of the overhead image; and a mask area setting unit that displays the overhead image on the display device and accepts the setting of a mask area to be covered with the mask image in the displayed overhead image.

[0009] According to one aspect of the present invention, it is possible to realize an overhead image output device for a work machine, an overhead image display system, and a work machine that can minimize the waste of useful images while reducing the recognition of image boundary portions.

[0010] FIG. 1 is a schematic perspective view showing the overall configuration of a work machine according to one embodiment of the present invention; FIG. 2 is a block diagram showing an example of the configuration of an overhead image display system and an overhead image output device according to one embodiment of the present invention; FIG. 3 is a diagram showing an example of an overhead image displayed on a display device of the overhead image display system, in which a mask image is not superimposed; FIG. 4 is a diagram showing an example of an overhead image displayed on a display device of the overhead image display system, in which a mask image is superimposed; FIG. 5 is a diagram showing an example of a default shape of a mask image area displayed on a mask area setting screen; FIG. 6 is a diagram showing an example of a mask area setting screen displayed on a display device of the overhead image display system; FIG. 7 is a diagram showing an example of a confirmation screen during mask area setting, included in the mask area setting screen.

[0011] [First Embodiment] Hereinafter, one embodiment of the present invention will be described in detail.

[0012] 1 is a schematic perspective view showing the overall configuration of a work machine 1 according to this embodiment. In this embodiment, the work machine 1 is exemplified by a backhoe, which is one type of construction machine.

[0013] As shown in Fig. 1, the work machine 1 includes a traveling device 2, a revolving body 3, and a working device 4. The revolving body 3 is supported on the frame of the traveling device 2 via a bearing body so as to be able to rotate about a vertical axis (an axis in the up-down direction). The revolving body 3 includes the working device 4, a cabin (operator's compartment) 5, a motor 6, a hood 7, a counterweight 8, etc.

[0014] The cabin 5 has a driver's seat inside where an operator (driver) sits. In the following description, the front side of the operator seated in the driver's seat will be referred to as the front, the rear side of the operator as the rear, the left side of the operator as the left side, and the right side of the operator as the right side. The cabin 5 is installed to the left of the rotating body 3.

[0015] Although not shown, a main display device and a display device 26 constituting an overhead image display system 20 (see FIG. 2 ), which will be described later, are installed inside the cabin 5. The main display device notifies the operator by displaying various types of information, etc. The display device 26 of the overhead image display system 20 displays an overhead image of the surroundings of the work machine 1.

[0016] The prime mover 6 is located at the rear of the revolving unit 3. The prime mover 6 is located on the rear side of the cabin 5. The prime mover 6 is covered by a hood 7. The hood 7 is provided at the rear of the revolving unit 3 and covers the rear of the prime mover 6 in an openable and closable manner. The hood 7 is provided so as to be openable and closable, with the front side near the rear of the cabin 5 as its axis. The counterweight 8 is a weight for balancing the weight of the work device 4, and is located below (below) the hood 7.

[0017] The working device 4 is a device that operates using hydraulic oil pressure as a working fluid pressure, and is installed at the front of the working machine 1, specifically at the front of the revolving body 3. The working device 4 includes a first boom 11, a second boom 12, an arm 13, a bucket 14, etc. that are rotated by hydraulic cylinders. The working device 4 performs work such as excavation and ground leveling.

[0018] (Overhead image display system) Fig. 2 is a block diagram that schematically shows an example configuration of an overhead image display system 20 and an overhead image output device 240 according to this embodiment. As shown in Fig. 2, the overhead image display system 20 includes a first camera 21, a second camera 22, and a third camera 23 mounted on the revolving body 3 of the work machine 1, a control unit 24 that controls the various components of the overhead image display system 20, and a storage unit 25 that stores various data used by the overhead image display system 20. Images captured by the first camera 21, the second camera 22, and the third camera 23 are input to the control unit 24.

[0019] The overhead image display system 20 also includes a display device 26 and an input device 27 that accepts input of various data to the overhead image display system 20. In this embodiment, the input device 27 and the display device 26 include a touch panel 28, as shown in the example of FIG.

[0020] Furthermore, the bird's-eye view image display system 20 includes a communication device 29 for communicating with other devices. The communication device 29 is formed of, for example, a wireless device for connecting to a network 30.

[0021] The first camera 21 is attached, for example, to the left part of the revolving unit 3, captures an image of the left side of the revolving unit 3, and outputs the captured image to a later-described overhead image generating unit 241 of the control unit 24. The second camera 22 is attached, for example, to the rear part of the revolving unit 3, captures an image of the rear of the revolving unit 3, and outputs the captured image to the overhead image generating unit 241. The third camera 23 is attached, for example, to the right part of the revolving unit 3, captures an image of the right side of the revolving unit 3, and outputs the captured image to the overhead image generating unit 241.

[0022] The control unit 24 is connected to each device of the work machine 1, including the main display device, via an in-vehicle network 31 such as a CAN (Controller Area Network). The control unit 24 is configured, for example, by a microcomputer that combines a CPU that executes calculations, a ROM that stores programs for the calculations, and a RAM that stores records of the calculation process and temporary control variables. The control unit 24 executes the stored programs to perform processes such as image synthesis, processing, and recording.

[0023] The control unit 24 includes an overhead image generating unit 241, a display control unit 242, and a mask region setting unit 243. In other words, the control unit 24 configures an overhead image output device 240.

[0024] The overhead image generating unit 241 generates an overhead image 50 (see FIG. 3 ) of the surroundings of the work machine 1, which will be described later, based on the images input from the first camera 21, the second camera 22, and the third camera 23. The overhead image 50 includes a main body image 51 representing the work machine 1. Note that a method for generating (combining) an overhead image using images captured by the cameras may use a well-known technique, and a detailed description thereof will be omitted.

[0025] The display control unit 242 displays the overhead image 50 generated by the overhead image generation unit 241 on the display device 26 by superimposing a mask image M (see FIG. 4 ) described later on an image-missing region R (see FIG. 3 ) described later in the overhead image 50. The display control unit 242 may output a signal to be output to the display device 26 to the storage unit 25, and record the image to be displayed on the display device 26 in the storage unit 25.

[0026] 3 is a diagram showing an example of an overhead image 50 displayed on the display device 26 without a superimposed mask image M. No camera is mounted on the front of the revolving unit 3. Therefore, as shown in FIG. 3, in the overhead image 50, an image-missing region R where an image is missing exists in front of the main image 51.

[0027] 3, the image boundary 52 in the missing region R in the overhead image 50 is not a straight line. If the image boundary 52 has angular portions such as steps, an operator who views the overhead image 50 while operating a work machine may mistake the angular portions for obstacles such as pillars.

[0028] Therefore, as shown in Fig. 4, the overhead image output device 240 displays a mask image M that hides the missing region R of the overhead image 50 so that the image boundary 52 of the image is not visible. Fig. 4 is a diagram showing an example of a display of the overhead image 50 on the display device 26, with the mask image M superimposed thereon.

[0029] The mask area setting unit 243 accepts the setting of a mask area in the overhead image 50. The mask area setting unit 243 displays the overhead image 50 on the display device 26, and accepts the setting of a mask area in which the displayed overhead image 50 is covered with a mask image M.

[0030] In this embodiment, the mask area setting unit 243 displays a mask area setting screen D (see FIG. 6 ), which will be described later, on the display device 26 and accepts the setting of the mask area on the mask area setting screen D. The mask area setting screen D includes a mask image area S, which becomes the mask image M after the shape and orientation position are adjusted.

[0031] The mask area setting unit 243 displays the mask image area S superimposed on the overhead image 50. The mask area setting unit 243 accepts adjustments to the shape and arrangement position of the mask image area S.

[0032] Fig. 5 is a diagram showing an example of the default shape of the mask image area S displayed on the mask area setting screen D. As shown in Fig. 5, the mask image area S has a shape having a pair of slanted sides that incline in directions that move away from each other as the area moves away from the center of the overhead image 50. Specifically, the pair of slanted sides includes a left boundary line L1 and a right boundary line L2, and the inclination angles of the left boundary line L1 and the right boundary line L2 can be adjusted.

[0033] The shape having a pair of inclined sides may be a triangle with one vertex located on the side of the center of the overhead image 50 where the main image 51 is located, as indicated by reference numeral 501. Alternatively, the shape may be a sector with its center located on the side of the center of the overhead image 50 where the main image 51 is located, as indicated by reference numeral 502.

[0034] Alternatively, as indicated by reference numeral 503, the shape may be a trapezoid in which the shorter of two parallel sides is located closer to the center of overhead image 50 where main image 51 is located. Alternatively, as indicated by reference numeral 504, the shape may be closed by two arcs of different radii and two radial line segments connecting the arcs, with the arc of the smaller radius located closer to the center of overhead image 50 where main image 51 is located.

[0035] Furthermore, the left boundary line L1 and the right boundary line L do not necessarily have to be straight lines, but may be smooth curves, or wavy lines or broken lines (jagged lines) that the operator can instantly identify as processing lines.

[0036] The display control unit 242 superimposes the mask image M corresponding to the mask area set by the mask area setting unit 243 on the overhead image 50 generated by the overhead image generation unit 241 and displays it on the display device 26 .

[0037] (Mask Area Setting) Fig. 6 is a diagram showing an example of a mask area setting screen D displayed on the display device 26. As shown in Fig. 6, the mask area setting screen D includes a confirmation screen D1 and a reception screen D2. On the confirmation screen D1, a mask image area S for setting a mask area is displayed superimposed on an overhead image 50. In the screen example of Fig. 6, a triangular mask image area S is displayed. Furthermore, the display example of Fig. 6 shows a state in which the entire mask image area S, which will be described later, is selected.

[0038] The reception screen D2 accepts adjustments to the shape and position of the mask image region R. The reception screen D2 displays instruction keys for accepting adjustments to the shape and position of the mask image region R. The mask region setting unit 243 changes the display of the mask image region S on the confirmation screen D1 in accordance with the adjustment content accepted on the reception screen D2.

[0039] 7 is a diagram showing an example of a display of a confirmation screen D1 during mask area setting on the mask area setting screen D. As shown in Fig. 7, during mask area setting, only the outline (contour) SL of the mask image area S on the confirmation screen D1 may be displayed. In other words, one display form of the mask image area S may include a form in which only the outline of the mask image area S is displayed.

[0040] In this manner, when only the outline SL of the mask image region R is displayed, the overhead image 50 is displayed inside the outline SL. This allows the shape and position of the mask image region S to be adjusted while directly viewing the image portion obscured by the mask image M. This makes it even easier to set a mask region that minimizes the image portion obscured by the mask image M.

[0041] 6, the instruction keys displayed on the reception screen D2 include, for example, a default position button B1, a left button B2, a right button B3, an up button B4, a down button B5, a setting confirmation button B6, and a close button B7. These instruction keys are used to accept settings for the inclination angles of the left boundary line L1 and the right boundary line L2 of the mask image area S, as well as the vertical position of the mask image area S.

[0042] Specifically, the default position button B1 sets the vertical position and central angle of the mask image area S to default values. In the default state, the central angles of the left boundary line L1 and the right boundary line L2 are equal and symmetrical. Pressing the default position button B1 returns the vertical position and central angle of the mask image area S to the default values. The provision of the default position button B1 makes it easy to redo adjustments to the mask image area S.

[0043] The left button B2 and the right button B3 are used to select an adjustment target in the mask image area S. By pressing either the left button B2 or the right button B3, one of the following (1) to (3) in the mask image area S is selected.

[0044] (1) Left Boundary Line L1 When the left boundary line L1 is in a selected state, the left boundary line L1 is displayed in a predetermined color, such as yellow. When the left boundary line L1 is not selected, the left boundary line L1 is displayed in a predetermined color, such as gray, that is different from the selected state.

[0045] (2) Right Boundary Line L2 When the right boundary line L2 is in a selected state, the right boundary line L2 is displayed in a predetermined color, such as blue. When the right boundary line L2 is in a non-selected state, the right boundary line L2 is displayed in a predetermined color, such as gray, that is different from the selected state. Note that the colors indicating that the left boundary line L1 and the right boundary line L2 of the mask image area are in a selected state may be the same color, as long as they are different from the color indicating the non-selected state.

[0046] (3) Entire Mask Image Area S When the entire mask image area S is selected, the entire mask image area S is filled with a predetermined color, such as red. As described above, the display example in Fig. 6 shows a state in which the entire mask image area S is selected. In a non-selected state, the inside of the mask image area S is not filled in, and the overhead image 50 located within the mask image area S can be seen.

[0047] For example, when the right button B3 is pressed repeatedly, the selection state of the mask image area S changes as follows: left boundary line L1 (yellow) ⇒ right boundary line L2 (blue) ⇒ entire mask image area S (filled in red) ⇒ left boundary line L (yellow) ⇒ . . .

[0048] When the left button B2 is pressed repeatedly, the selection state is changed in the reverse order to when the right button B3 is pressed repeatedly: the entire mask image area S (filled in red) ⇒ right boundary line L2 (blue) ⇒ left boundary line L1 (yellow) ⇒ entire mask image area S ⇒ ...

[0049] When any of the above (1) to (3) of the mask image area S is selected, pressing the up button B4 or the down button B5 changes the part of the selected mask image area S as follows:

[0050] (A) State in which the left boundary line L1 is selected Pressing the up button B4 rotates the left boundary line L1 in the negative direction (counterclockwise). Pressing the down button B5 rotates the left boundary line L1 in the positive direction (clockwise). The central angle θ1 of the left boundary line L1 can be changed within a range of, for example, -45° to 0° (see FIG. 7), with 0° being directly above the displayed image.

[0051] (B) State when the right boundary line L2 is selected Pressing the up button B4 rotates the right boundary line L2 in the negative direction. Pressing the down button B5 rotates the right boundary line L2 in the positive direction. The central angle θ2 (see FIG. 7) of the right boundary line L2 can be changed within a range of 0° to 45°, with 0° being directly above the displayed image.

[0052] (C) State in which the entire mask image area S is selected Pressing the up button B4 moves the entire mask image area S upward. Pressing the down button B5 moves the entire mask image area S downward.

[0053] The setting confirmation button B6 is used to confirm the settings. When the setting confirmation button B6 is pressed, the shape and layout position of the mask image area S displayed on the confirmation screen D1 are set as the mask area, and the shape and layout position of the mask image M are confirmed. The close button B7 is used to close the mask area setting screen D.

[0054] (Description of Effects) As described above, according to the overhead-view image display system 20, the mask area setting unit 243 in the overhead-view image output device 240 accepts the setting of a mask area for the overhead-view image 50 generated by the overhead-view image generation unit 241 while the overhead-view image 50 is being displayed. The mask area after the setting becomes the mask image M, and the display control unit 242 displays the overhead-view image 50 on the display device 26 with the mask image M superimposed thereon.

[0055] The position of the image boundary in the overhead image 50 differs depending on the mounting positions of the first camera 21, the second camera 22, and the third camera 23 mounted on the revolving body 3. Therefore, since the mounting positions of the multiple cameras differ depending on the model, the overhead image display system 20 (overhead image output device 240) in which the mask area (mask image M) is fixed cannot be shared among different models.

[0056] Furthermore, since the camera mounting position is the same for the same model, it is possible to fix the mask area. However, in this case, the camera mounting position must be highly accurate so that it fits the fixed mask area, which increases the amount of work required to correct the mounting position during the camera mounting process. Furthermore, even if the camera can be mounted with high accuracy, if distortion or the like occurs in the work machine 1, it will deviate from the mask area, and the mounting position will need to be corrected again.

[0057] In contrast, with the overhead image display system 20 (overhead image output device 240), the mask area can be set to match the actual overhead image 50 using images captured by the first camera 21, the second camera 22, and the third camera 23 mounted on the work machine 1.

[0058] This allows the system to be shared among different models with completely different camera mounting positions, meaning that mask images can be adjusted without changing the system software for each model.

[0059] Furthermore, the precision of the camera mounting position can be reduced, and the number of steps required for the camera mounting process can be reduced. Furthermore, even if distortion or the like occurs in the work machine 1, this can be addressed by simply resetting the mask area without correcting the camera mounting position.

[0060] Moreover, since the mask area can be set while viewing the displayed overhead image 50, it is possible to easily set a mask area that minimizes the image portion that is obscured by the mask image M. This reduces the portion of the image that is obscured by the mask image M and that can be effectively displayed without causing any problems, while also reducing misperception by the driver.

[0061] Furthermore, according to the overhead image display system 20 (overhead image output device 240), when setting a mask area, the mask area setting unit 243 displays a mask area setting screen D. The mask area setting screen D includes a confirmation screen D1 on which a mask image area S for setting the mask area is displayed superimposed on the overhead image 50, and a reception screen D2 on which adjustments to the shape and arrangement position of the mask image area S are received.

[0062] This allows the mask area to be set by adjusting the shape and arrangement position of the mask image area S displayed on the confirmation screen D1. Therefore, the mask area can be set more easily than in a configuration in which the mask area is set by drawing it from scratch on the overhead image 50.

[0063] Furthermore, the mask area setting unit 243 can adjust the inclination angle of each of the left boundary line L1 and the right boundary line L2, which are a pair of inclined sides in the mask image area S. This makes it even easier to set a mask area that minimizes the portion of the image that is not displayed and is wasted.

[0064] (Modification) In the above-described configuration, the entire mask image area S is moved upward by operating the command key on the reception screen D2, but for example, only the vertex of a triangle located on the central side of the overhead image 50 may move, and the shape (outer shape) of the triangle may change in accordance with this movement. The same applies to the default shape of the mask image area S other than a triangle, such as a fan shape.

[0065] Furthermore, after adjusting the inclination angle of one of the pair of inclined sides, the left boundary line L1 or the right boundary line L2, a function may be provided to adjust the angle of the other boundary line in the opposite direction with a single touch so that the absolute value remains the same. When the left and right image boundaries are nearly line-symmetrical, such a function allows for quick setting of the mask area.

[0066] Furthermore, in the above-described configuration, the adjustment range of the pair of inclined sides, the left boundary line L1 and the right boundary line L2, is set to a total of 90° with central angles θ1 and θ2 having 0° directly above, but the range may be narrower or wider than 90°.

[0067] Furthermore, in the above-described configuration, an example has been described in which no camera is installed at the front of the work machine 1 (swivel unit 3), and a general example has been described in which multiple cameras are installed in a work machine, but this is not limited to this. That is, a configuration may also be possible in which no camera is installed at the left or right of the work machine 1 (swivel unit 3), and a mask image M is placed in a missing region R of the image located on the left or right side of the overhead image.

[0068] In the above-described configuration, the display device 26 of the overhead image display system 20 is provided separately from the display unit of the main display device, but the overhead image on which the mask image is superimposed may be sent from the overhead image output device 240 to the main display device 15, and the main display device may display the overhead image 50. The main display device may be a touch panel, and the mask area setting screen D may also be displayed on the main display device to accept instruction input.

[0069] Alternatively, the confirmation screen D1 may be displayed on the display device 26, and the reception screen D2 may be displayed on the main display device. Alternatively, a signal for displaying the mask area setting screen D may be outputted externally using the communication device 29 to a mobile terminal or the like that is permitted to access the work machine 1, and the mask area may be set on the mobile terminal. Furthermore, although a swiveling construction machine has been exemplified as the work machine, it goes without saying that the present invention can also be applied to a work machine that does not swivel.

[0070] [Example of implementation using software] The functions of the overhead image output device 240 (hereinafter referred to as the "device") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as each control block of the device.

[0071] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The functions described in each of the above embodiments are realized by executing the program using the control device and storage device.

[0072] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0073] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0074] Furthermore, each process described in each of the above embodiments may be executed by AI (Artificial Intelligence). In this case, the AI ​​may run on the control device or on another device (for example, an edge computer or a cloud server).

[0075] (Summary) The overhead image output device in aspect 1 of the present invention is an overhead image output device mounted on a work machine, and includes: an overhead image generation unit that generates an overhead image of the surroundings of the work machine based on images captured by a plurality of cameras mounted on the work machine; a display control unit that displays the generated overhead image on a display device by superimposing a mask image on missing areas of the overhead image; and a mask area setting unit that displays the overhead image on the display device and accepts setting of a mask area to be covered with the mask image in the displayed overhead image.

[0076] According to the above configuration, the mask area can be set to match the actual overhead image using images captured by multiple cameras mounted on the work machine. This allows it to be shared among different models. In addition, the precision of the camera mounting position can be reduced, reducing the number of steps required for the camera mounting process. This can be achieved by simply resetting the mask area without correcting the camera mounting position.

[0077] Moreover, since the mask area can be set while visually checking the displayed overhead image, it is possible to easily set the mask area so as to minimize the portion of the image that is not displayed and is wasted.

[0078] In the overhead image output device of Aspect 2 of the present invention, in Aspect 1, the mask area setting unit displays a mask area setting screen on the display device, and the mask area setting screen includes a confirmation screen in which a mask image area for setting the mask area is displayed superimposed on the overhead image, and a reception screen for receiving adjustments to the shape and position of the mask image area, and the mask area setting unit may change the display of the mask image area on the confirmation screen in accordance with the content of the adjustments received on the reception screen.

[0079] According to the above configuration, the mask area can be set by adjusting the shape and placement position of the mask image area, making it easier to set the mask area compared to setting the mask area by tracing the overhead image from scratch.

[0080] The overhead image output device of Aspect 3 of the present invention may include, in Aspect 2, a mode in which only the outline of the mask image region is displayed as one of the display modes of the mask image region. According to the above configuration, the shape and layout position of the mask image region can be adjusted while directly viewing the image portion that is covered by the mask image, making it even easier to set the mask region so as to minimize the image portion that is not displayed and is wasted.

[0081] In the overhead image output device according to Aspect 4 of the present invention, in Aspect 2 or 3, the mask image area may have a shape having a pair of slanted sides that slant apart with increasing distance from a center of the overhead image, and the reception screen may accept adjustment of the slant angle for each of the pair of slanted sides. This configuration makes it even easier to set a mask area that minimizes the portion of the image that is not displayed and is wasted.

[0082] In the overhead image output device of aspect 5 of the present invention, in any of aspects 2 to 4, the mask image area may be triangular with one vertex located on the side of the center of the overhead image, or fan-shaped with its center located on the side of the center of the overhead image.

[0083] The overhead image display system in aspect 6 of the present invention is an overhead image display system mounted on a work machine, and comprises a plurality of cameras mounted on the work machine, a display device mounted on the work machine, an input device, and an overhead image output device of any one of aspects 1 to 4 of the present invention.

[0084] A working machine according to a seventh aspect of the present invention includes a traveling device, a working device, and the overhead image display system according to the sixth aspect.

[0085] The overhead image output device according to each aspect of the present invention may be realized by a computer. In this case, the control program for the overhead image output device, which causes the computer to operate as each part (software element) of the overhead image output device, thereby realizing the overhead image output device on the computer, and the computer-readable recording medium on which the control program is recorded, also fall within the scope of the present invention.

[0086] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0087] REFERENCE SIGNS LIST 1 Work machine 2 Traveling device 4 Work device 20 Bird's-eye view image display system 21 First camera 22 Second camera 23 Third camera 26 Display device 27 Input device 50 Bird's-eye view image 52 Image boundary 240 Bird's-eye view image output device 241 Bird's-eye view image generating unit 242 Display control unit 243 Mask area setting unit D Mask area setting screen D1 Confirmation screen D2 Reception screen L1 Left boundary line (inclined edge) L2 Right boundary line (inclined edge) M Mask image R Missing area of ​​image S Mask image area

Claims

1. An overhead image output device mounted on a work machine, comprising: an overhead image generation unit that generates an overhead image of the surroundings of the work machine based on images captured by a plurality of cameras mounted on the work machine; a display control unit that displays the generated overhead image on a display device by superimposing a mask image over image-missing areas in the overhead image; and a mask area setting unit that displays the overhead image on the display device and accepts setting of a mask area to be covered with the mask image in the displayed overhead image.

2. The overhead image output device of claim 1, wherein the mask area setting unit displays a mask area setting screen on the display device, the mask area setting screen including: a confirmation screen in which a mask image area for setting the mask area is displayed superimposed on the overhead image; and a reception screen in which adjustments to the shape and position of the mask image area are received; and the mask area setting unit changes the display of the mask image area on the confirmation screen in accordance with the content of the adjustments received on the reception screen.

3. The overhead image output device according to claim 2, wherein one of the display modes of the mask image region includes a mode in which only the outline of the mask image region is displayed.

4. The overhead image output device according to claim 2, wherein the mask image area has a shape having a pair of inclined sides that incline in directions away from each other as the area moves away from the center of the overhead image, and the reception screen accepts adjustment of the inclination angle for each of the pair of inclined sides.

5. The overhead image output device according to claim 4, wherein the mask image area is triangular with one vertex located on the side of the center of the overhead image, or fan-shaped with its center located on the side of the center of the overhead image.

6. An overhead image display system mounted on a work machine, comprising: a plurality of cameras mounted on the work machine; a display device mounted on the work machine; an input device; and an overhead image output device according to any one of claims 1 to 5.

7. A work machine comprising: a traveling device; a work device; and the overhead image display system according to claim 6.

8. A program for causing a computer to function as the overhead image output device according to any one of claims 1 to 5, the program causing a computer to function as the overhead image generation unit, the display control unit, and the mask area setting unit.

9. A computer-readable recording medium on which the program according to claim 8 is recorded.

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