Camera attitude detection device and work region line display device

This application is a National Stage Patent Application of PCT International Patent Application No. PCT/JP2014/063229 (filed on May 19, 2014) under 35 U.S.C. §371, which claims priority to Japanese Patent Application Nos. 2014-102874 (filed on May 16, 2014) and 2013-107027 (filed on May 21, 2013), which are all hereby incorporated by reference in their entirety.

The present invention relates to a camera attitude detection device and a work region line display device which calculate an attitude angle of a camera without using an inclination angle detection sensor.

Conventionally, there has been known a suspended load position detection device in which a camera is provided at a tip of a boom (see Patent Literature 1).

In the suspended load position detection device, a camera is provided at a tip of a boom, an image of a suspending rope and a hook is captured with the camera from above, a rope point where the color of the suspending rope exists is calculated for each scanning line from the color distribution on a plurality of the scanning lines in the captured image by image processing, each of the rope points is joined by a straight line, and an intersection point of the straight lines corresponding to the suspending rope is calculated as a suspended load position.

Patent Literature

Patent Literature 1: JP 3440598 B

Problems to be Solved by the Invention

Incidentally, in the suspended load position detection device, since an inclination angle detection sensor to detect an inclination angle of the camera is not provided, the precise position of the suspended load cannot be calculated when the camera inclines, and there is a problem that the suspended load position detection device is expensive when the inclination angle detection sensor is provided.

An object of the present invention is to provide a camera attitude detection device which can detect an attitude angle of a camera without providing an inclination angle detection sensor, and a work region line display device using the camera attitude detection device.

Solutions to Problems

An invention of claim 1 is a camera attitude detection device including: a camera provided at a tip of a boom of a working machine; a monitor configured to display an image, captured by the camera, of a hook suspended from the tip of the boom; and an attitude angle calculation device configured to calculate, based on hook image position information on a screen displayed on the monitor and hook position information in a real space, an attitude angle of the camera.

Effects of the Invention

According to the present invention, it is possible to detect an attitude angle of a camera without providing an inclination angle detection sensor.

FIG. 1 is a side view illustrating a mobile crane equipped with a work region line display device according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of the work region line display device.

FIG. 3 is an explanatory diagram illustrating how to calculate a position of a work region line on a screen when a monitoring camera inclines.

FIG. 4 is an explanatory diagram illustrating an example of an image displayed on a monitor.

FIG. 5 is an explanatory diagram illustrating how to calculate an inclination angle of the monitoring camera from a position of a hook on the screen when the monitoring camera inclines.

FIG. 6 is an explanatory diagram illustrating a coordinate system and a positional relation between a sheave at a boom tip, the monitoring camera, and the hook.

FIG. 7 is an explanatory diagram illustrating a state in which the hook swings.

FIG. 8 is a block diagram illustrating a configuration of another example of a camera attitude detection device.

FIG. 9 is a block diagram illustrating a configuration of an image processing unit illustrated in FIG. 8 .

FIG. 10 is a block diagram illustrating a configuration of another example of a camera attitude detection device.

FIG. 11 is a block diagram illustrating a configuration of an image processing unit of the camera attitude detection device illustrated in FIG. 10 .

FIG. 12 is an explanatory diagram illustrating a configuration of a camera attitude detection device of a second embodiment.

FIG. 13 is an explanatory diagram illustrating a hook image displayed on the monitor, a radial direction line passing through the hook image, and a movement locus of the hook.

FIG. 14 is a block diagram illustrating a configuration of a work region line display device of a third embodiment.

FIG. 15 is a block diagram of the work region line display device in which a configuration of a control illustrated in FIG. 14 is detailedly illustrated.

FIG. 16 is an explanatory diagram illustrating states before and after the hook image is fitted in a frame displayed in the center of the monitor.

FIG. 17 is an explanatory diagram illustrating theory to geometrically calculate the work region line.

FIG. 17A is an explanatory diagram illustrating that an offset is changed according to a derricking angle of a telescopic boom.

FIG. 17B is an explanatory diagram illustrating that an inclination angle of the monitoring camera is fixed regardless of the derricking angle of the telescopic boom when a rotating shaft of the monitoring camera coincides with a center of the sheave.

FIG. 18 is an explanatory diagram illustrating the monitor screen on which the frame, the hook image, and the work region line are displayed.

FIG. 19 is a block diagram illustrating a configuration of a work region line display device of a fourth embodiment.

FIG. 20 is a block diagram illustrating a configuration of the work region line display device of the fourth embodiment.

FIG. 21 is a block diagram illustrating a configuration of a work region line display device of a fifth embodiment.

FIG. 22 is an explanatory diagram illustrating a monitor screen of a work region line display device of a seventh embodiment.

FIG. 23 is an explanatory diagram illustrating a monitor screen of another example.

Hereinafter, embodiments of a camera attitude detection device and a work region line display device according to the present invention will be described with reference to the drawings.

First Embodiment

FIG. 1 illustrates a rough terrain crane 10 as a crane (working vehicle) which is a working machine equipped with a work region line display device including a camera attitude detection device. The rough terrain crane 10 (hereinafter, referred to as a crane) includes a carrier 11 which is a main body of a vehicle having a traveling function, a pair of right and left front side outriggers 12 which is provided at a front side of the carrier 11 , a pair of right and left rear side outriggers 13 which is provided at a rear side of the carrier 11 , a swivel base 14 horizontally swivelably mounted on a upper part of the carrier 11 , a cabin 20 provided on the swivel base 14 , and a telescopic boom 16 mounted on a bracket 15 fixed to the swivel base 14 .

The telescopic boom 16 is mounted, by a base end thereof, through a supporting shaft 17 and is derrickably about the supporting shaft 17 . A derricking cylinder 18 is interposed between the bracket 15 and the telescopic boom 16 , and the telescopic boom 16 performs derricking movements by expansion/contraction of the derricking cylinder 18 .

The telescopic boom 16 includes a base boom 16 A, an intermediate boom 16 B, and a top boom 16 C, and is configured in the base boom 16 A by telescopically assembling them in this order from the outside to the inside. Furthermore, the telescopic boom 16 expands and contracts by an extension cylinder (not illustrated).

A sheave 23 (see FIG. 5 ) is provided at a tip of the top boom 16 C, a wire rope 25 (hereinafter, referred to as a wire) is hung on the sheave 23 , and a hook block 19 is suspended by the wire 25 . A hook 21 is mounted on the hook block 19 .

The wire 25 is wound or drawn out by a winch, which is not illustrated.

A camera unit 30 is mounted on the tip of the top boom 16 C.

The camera unit 30 includes a housing 31 mounted on the tip of the top boom 16 C through a damper so as to continuously face downward by its own weight, a monitoring camera (camera) 32 which is a TV camera or the like provided inside the housing 31 so as to incline to a pan direction and a tilt direction, a pan motor 33 (see FIG. 2 ) to incline the monitoring camera 32 to the pan direction, and a tilt motor 34 to incline the monitoring camera 32 to the tilt direction.

Note that, although the camera unit 30 is configured so as to face downward by its own weight, an optical axis does not accurately continuously face directly downward due to the resistance of the damper, the frictional resistance of the movable parts, or the like. Furthermore, in the embodiment, the pan motor 33 , the tilt motor 34 , a zoom function, or the like is not necessarily required.

The inclination (direction) of the monitoring camera 32 is adjusted by the operation of a pan switch (attitude operation means) SW 1 (see FIG. 2 ) and a tilt switch SW 2 (attitude operation means) of an operation unit (not illustrated) provided in the cabin 20 . Furthermore, the monitoring camera 32 is zoomed by the operation of a zoom switch SW 3 .

[Work Region Line Display Device]

FIG. 2 is a block diagram illustrating a configuration of a work region line display device 120 .

The work region line display device 120 includes a work region calculation unit 66 of a controller 60 and a camera attitude detection device 100 .

[Camera Attitude Detection Device]

The camera attitude detection device 100 includes the camera unit 30 provided at a tip of the telescopic boom 16 , a boom attitude detection sensor 50 to detect the attitude of the telescopic boom 16 , the controller 60 (except the work region calculation unit 66 ) to calculate, based on a detection signal and the like detected by the boom attitude detection sensor 50 , an attitude angle of the monitoring camera 32 and a work region line, a monitor 70 on which the image captured by the monitoring camera 32 is displayed, and a touch panel 71 attached to a screen (not illustrated) of the monitor 70 .

The boom attitude detection sensor 50 detects an unwound amount of the hook 21 , the length and derricking angle of the telescopic boom 16 , the swivel angle of the telescopic boom 16 , or the like, includes sensors (not illustrated) to detect them, and outputs hook position information in a real space.

[Controller]

As illustrated in FIG. 2 , the controller 60 includes a motor control unit 61 to drive and control, based on the operation of the pan switch SW 1 and the tilt switch SW 2 , the pan motor 33 and the tilt motor 34 , a viewpoint transformation calculation unit (reference hook position calculation means) 62 , the work region calculation unit 66 , an image combining unit 67 , and an attitude angle calculation device 68 .

The attitude angle calculation device 68 includes a hook position calculation unit 63 , a shift amount calculation unit 64 , and a camera inclination angle calculation unit (camera attitude angle calculation means) 65 .

[Viewpoint Transformation Calculation Unit]

First, the viewpoint transformation calculation unit 62 calculates, based on the inclination angle of the tip of the telescopic boom 16 and the unwound amount of the hook 21 , the position of the hook 21 in an X, Y, Z coordinate system where the boom tip (the center of the sheave 23 illustrated in FIG. 6 ) is set as an origin.

Furthermore, the viewpoint transformation calculation unit 62 assumes that the monitoring camera 32 faces directly downward, transforms the position (position in the X,Y,Z coordinate system) of the hook 21 in the real space into the position in an x3,y3,z3 coordinate system (see FIG. 6 ) where the point, at which the optical center position of the monitoring camera 32 coincides with the center position of the captured image, is set as an origin, transforms the position of the hook 21 in the x3,y3,z3 coordinate system into the position in a coordinate system (screen coordinate system) on the screen of the monitor 70 , and calculates the position as a reference position (reference hook position) on the screen of the monitor 70 .

In other words, when it is assumed that the monitoring camera 32 faces directly downward, the reference position, which is the position of the hook 21 displayed on the screen of the monitor 70 , is calculated as the coordinate position on the screen.

Furthermore, the viewpoint transformation calculation unit 62 has a function of height detection means for calculating, based on the detection signal detected by the boom attitude detection sensor 50 , the height (hook position information) in the height direction from the optical center position of the monitoring camera 32 to the hook 21 .

[Hook Position Calculation Unit]

The touch panel 71 on the hook image displayed on the screen of the monitor 70 is touched, and thereby the hook position calculation unit 63 calculates the hook position in the screen coordinate system (on the screen of the monitor 70 ) on the image captured by the monitoring camera 32 facing in an arbitrary direction.

[Shift Amount Calculation Unit]

The shift amount calculation unit 64 calculates, based on the hook position calculated by the hook position calculation unit 63 , a shift amount of the hook position with respect to the reference position calculated by the viewpoint transformation calculation unit 62 , that is, the shift amount which is the difference between the reference position and the hook position (hook image position information).

[Camera Inclination Angle Calculation Unit]

The camera inclination angle calculation unit 65 calculates the inclination angle of the monitoring camera 32 (inclination to the perpendicular line) based on the shift amount calculated by the shift amount calculation unit 64 and a height h 1 , which is calculated by the viewpoint transformation calculation unit 62 and the height from an optical center position Q 1 (see FIG. 5 ) of the monitoring camera 32 to the hook 21 . In other words, the camera inclination angle calculation unit 65 calculates the attitude angle of the monitoring camera 32 based on the hook image position information and the hook position information in the real space.

[Work Region Calculation Unit]

The work region calculation unit 66 calculates, based on the load weight of a suspended load, the work region line indicating the region, the center of which is swivel center of the telescopic boom 16 , where the suspended load is movable, and further calculates, based on the inclination angle of the monitoring camera 32 , the precise position of the work region line on the image on the monitor 70 .

The load weight of the suspended load is calculated by a calculation unit, which is not illustrated, of the controller 60 based on cylinder pressure detected by a pressure sensor (not illustrated) of the derricking cylinder 18 , the derricking angle of the telescopic boom 16 , and the length of the telescopic boom 16 .

Here, the position of the work region line on the screen when the monitoring camera 32 inclines will be briefly described.

As illustrated in FIG. 3 , it is assumed that the height of the monitoring camera 32 from the ground is h, the ground position directly under the monitoring camera 32 is P 1 , the swivel center position of the telescopic boom 16 is O, and the work region line, the center of which is the swivel center position O, is S 1 . It is assumed that the distance from the swivel center position O to the work region line S 1 is Sa. The height h can be calculated by the length and derricking angle of the boom 16 .

When the monitoring camera 32 faces directly downward, it is assumed that the optical axis of the monitoring camera 32 at this time is 32 a , and the position P 1 which is the intersection point of the optical axis 32 a and the ground is displayed at the center position on the screen of the monitor 70 .

When the monitoring camera 32 inclines at angle θ, a position P 2 , which is the intersection point of an optical axis 32 b of the monitoring camera 32 at this time and the ground, is displayed at the center position on the screen of the monitor 70 . Note that, the turning center position and optical center position Q 1 (see FIG. 5 ) of the monitoring camera 32 coincide.

It is assumed that the distance between the position P 1 and the position P 2 is ΔR 1 , ΔR 1 can be calculated as h*tan θ as long as the angle θ is known, and the position P 1 can be calculated from the position P 2 . Furthermore, it is assumed that a work radius of the telescopic boom 16 from the swivel center position O of the telescopic boom 16 is R 1 , the swivel center position O can be calculated from the position P 1 . Note that, the work radius R 1 is calculated from the length and derricking angle of the telescopic boom 16 .

Then, it is possible to calculate, based on the load weight, the position of the work region line S 1 on the ground setting the swivel center position O as the center. The position P 2 on the ground is the center position of the screen of the monitor 70 , and the position P 2 is positioned at the work radius R 1 +ΔR 1 from the swivel center position O.

Furthermore, a distance ΔR 2 from the position P 2 to the work region line S 1 is calculated as ΔR 2 =Sa−(R 1 +ΔR 1 ).

Here, since the center position of the image on the monitor 70 when the monitoring camera 32 inclines at the angle θ indicates the position P 2 on the ground and the height h is known, the coordinate position on the ground can be mapped to the coordinate position on the image. In other words, each position on the captured image can be mapped to the coordinate position in the crane coordinate system where the swivel center position O of the telescopic boom 16 is set as an origin.

Thus, it is possible to calculate the position of the image on the monitor 70 which corresponds to the position of the work region line S 1 on the ground.

[Image Combining Unit]

The image combining unit 67 combines the work region line S 1 on the position on the image corresponding to the position of the work region line S 1 calculated by the work region calculation unit 66 , and displays the combined image on the screen of the monitor 70 .

[Operation]

Next, the operation of the camera attitude detection device 100 and the work region line display device 120 which are configured as described above will be described.

It is assumed that the image of the hook block 19 is captured by the monitoring camera 32 , and, for example, a hook block image 19 S is displayed on a screen 70 Ga of the monitor 70 as illustrated in FIG. 4 . Note that, the description is based on the assumption that the position of the hook 21 is the position of a shaft 19 J (see FIG. 1 ) of a sheave (not illustrated) provided on the hook block 19 , and the hook image including the hook block image 19 S is denoted as 21 G for convenience of explanation. It is assumed that the monitoring camera 32 inclines in the tilt direction and the pan direction.

The operator touches the part of the touch panel 71 on the hook image 21 G displayed on the screen 70 Ga. The hook position calculation unit 63 calculates the coordinates Ch_tlt regarding a hook position C which is the touched position of the touch panel 71 as the position in an image coordinate system (the coordinate system where the upper end part of the left end of the screen is set as an origin). The coordinates C_htlt may be calculated by the image processing.

On the other hand, when it is assumed that the monitoring camera 32 faces directly downward, the viewpoint transformation calculation unit 62 calculates a position (reference position) B of the hook 21 on the screen of the monitor 70 when the image is captured by the monitoring camera 32 facing directly downward.

Here, it will be briefly described how to calculate the position B of the hook 21 on the screen when the monitoring camera 32 faces directly downward.

When the distance from a shaft 23 J (the center position of the sheave 23 ) of the sheave 23 at the tip of the telescopic boom 16 to the hook 21 is H 1 and that the distance in the height direction from the optical center position Q 1 of the monitoring camera 32 to the hook 21 is h 1 as illustrated in FIG. 5 , it is assumed that h 1 =H 1 −W 2 . The distance H 1 can be calculated from the unwound amount of the hook 21 , and an offset amount W 2 in the perpendicular direction between the sheave 23 and the monitoring camera 32 can be calculated from the mounted position of the monitoring camera 32 , the derricking angle of the telescopic boom 16 , or the like.

Then, it is assumed that the intersection point of the optical axis 32 a of the monitoring camera 32 and a base F 1 of a triangle F formed by joining the optical center position Q 1 , points Q 2 , and Q 3 is E 1 . Note that, the base F 1 is the horizontal line indicating the height position of the hook 21 , and the range between a line F 2 joining the optical center position Q 1 and the point Q 2 , and a line F 3 joining the optical center positions Q 1 and Q 3 , indicates the image capturing range of the monitoring camera 32 . The image capturing range is the range when the monitoring camera 32 faces directly downward. Furthermore, it is assumed that a position F 1 a on the base F 1 is the position of the hook 21 .

The intersection point E 1 is on the optical axis 32 a and is a center position G 0 of the screen 70 G of the monitor 70 . When the distance from the intersection point E 1 to the hook 21 is L 1 , it is assumed that L 1 =W 1 , and W 1 is the offset amount in the horizontal direction between the sheave 23 and the monitoring camera 32 . The offset amount W 1 can be calculated from the mounted position of the monitoring camera 32 , the derricking angle of the telescopic boom 16 , or the like.

Furthermore, the height h 1 can be calculated from the unwound amount of the hook 21 and the offset amount W 2 in the vertical direction between the sheave 23 and the monitoring camera 32 .

Thus, the position A of the hook 21 on the screen 70 G when it is assumed that the monitoring camera 32 faces directly downward can be calculated. Note that, 70 G in FIG. 5 illustrates the screen of the monitor 70 when the monitoring camera 32 faces directly downward.

When the monitoring camera 32 inclines at an angle θtilt, the image captured by the monitoring camera 32 is the screen 70 Ga of the monitor 70 , and the hook 21 appears at the position A of the screen 70 Ga as a real image. Note that, it is assumed that G 1 is the center position of the screen 70 Ga.

Since the position A separated by L 1 from the center position G 0 of the screen 70 G (the intersection point E 1 of the optical axis 32 a ) is the position of the hook 21 , the position separated by L 1 from the center position G 1 of the screen 70 Ga is the position of the hook 21 (reference hook position) B when it is assumed that the monitoring camera 32 faces directly downward. In other words, the position A of the screen 70 G and the position B of the screen 70 Ga are the same position of the screen.

The position B on the screen 70 Ga is calculated by the viewpoint transformation calculation unit 62 using a perspective transformation matrix.

To briefly describe this, the viewpoint transformation calculation unit 62 calculates, based on the distances H 1 and h 1 , and the offset amount W 1 , a position P_h of the hook block 19 in the X, Y, Z coordinate system, where the center of the sheave 23 is set as an origin, as illustrated in FIG. 6 .

Furthermore, the viewpoint transformation calculation unit 62 makes the optical center position Q 1 of the monitoring camera 32 coincident with the center of the captured image, calculates a position C_h of the hook block 19 as the position in a (x3, y3, z3) coordinate system where the center of the captured image is set as an origin, and calculates, based on the position C_h of the hook block 19 in the (x3, y3, z3) coordinate system, the position B of the screen 70 Ga of the monitor 70 in the image coordinate system. It is assumed that the coordinates of the position B on the screen is Ch_ver (see FIG. 4 ).

Furthermore, when it is assumed that the monitoring camera 32 faces directly downward, the viewpoint transformation calculation unit 62 calculates a movement locus T of the hook block 19 on the screen 70 Ga when the hook block 19 is raised or lowered. The image combining unit 67 combines the movement locus T and the position B on the image captured by the monitoring camera 32 and displays the combined image on the monitor 70 .

As illustrated in FIG. 4 , the shift amount calculation unit 64 calculates the difference between the coordinates C_h_tlt of the hook image, which is calculated by the hook position calculation unit 63 , and the coordinates C_h_ver, which is calculated by the viewpoint transformation calculation unit 62 , of the position B of the hook block 19 on the screen. In other words, the shift amount calculation unit 64 calculates the shift amounts Δx, Δy of the differences in the x direction and the y direction.

The camera inclination angle calculation unit 65 calculates the inclination angle of the monitoring camera 32 based on the following equations from the shift amount calculated by the shift amount calculation unit 64 .

tilt angle=tan −1 (Δ y/h 1)  (1)

pan angle=tan −1 (Δ x/h 1)  (2)

Here, it will be described how to calculate the inclination angle of the monitoring camera 32 with reference to FIG. 5 .

It is assumed that the monitoring camera 32 facing directly downward inclines at the angle θtilt in the tilt direction. It is assumed that the optical axis of the monitoring camera 32 inclining at the angle θtilt is 32 c , and a triangle formed at the position where the triangle F inclines at the angle θtilt is M. It is assumed that the intersection point of a base M 1 of the triangle M and the optical axis 32 c is P 3 , and a straight line joining the optical center position Q 1 and the position F 1 a is 32 d . It is assumed that the angle between the straight line 32 d and the optical axis 32 a is θh, and the angle between the straight line 32 d and the optical axis 32 c is θth.

Then, it is assumed that the intersection point of a straight line 32 e , the angle between which and the optical axis 32 c is θh, and the base M 1 is a position P 4 , and the position P 4 , which is the intersection point of the base M 1 of the triangle M is the position F 1 a of the base F 1 before the triangle F inclines. In other words, since the position F 1 a separated by the distance L 1 from the intersection point E 1 on the optical axis 32 a of the monitoring camera 32 facing directly downward is the position of the hook 21 , the position P 4 separated by the distance L 1 from the intersection point P 3 on the optical axis 32 C of the monitoring camera 32 inclining at the angle θtilt is the position of the hook 21 captured by the monitoring camera 32 facing directly downward.

Furthermore, the intersection point P 3 on the optical axis 32 c when the monitoring camera 32 inclines at the angle θtilt coincides with the center position G 1 of the screen 70 Ga of the monitor 70 . Moreover, the position P 4 separated by the distance L 1 from the intersection point P 3 is the position B of the screen 70 Ga. It is assumed that a separated distance between the position F 1 a and the position P 4 is Δy, the distance between the positions A and B on the screen 70 Ga is Δy.

Then, since θtilt=θh+θth, it is assumed that:

θtilt=tan −1 ( L 1/ h 1)+tan −1 ((Δ y−L 1)/ h 1)  (3)

From the positions A and B on the screen 70 Ga, Δy can be calculated, L 1 is known, and h 1 can be calculated form the unwound amount of the hook 21 , the derricking angle of the telescopic boom 16 , or the like.

Therefore, by touching the position A of the screen 70 Ga illustrated in FIG. 5 (the position C in FIG. 4 ), the hook position calculation unit 63 calculates the position A of the screen 70 Ga, and thereby the shift amount calculation unit 64 calculates, from the difference between the position A and the position B calculated by the viewpoint transformation calculation unit 62 , the distance Δy between the positions A and B. Then, the camera inclination angle calculation unit 65 calculates, from the distance Δy, the inclination angle θtilt of the monitoring camera 32 using the equation (3). Since the pan angle can be similarly calculated, the description thereof is omitted.

Although the inclination the angle θtilt can be accurately calculated with the equation (3), the tilt angle is calculated with the equation (1) and the pan angle is calculated with the equation (2) in order to simplify the calculation in the embodiment.

Here, when Δy=3 m, L 1 =0.5 m, and h 1 =10 m, the angle θtilt calculated with the equation (3) is 0.29494 rad, and the angle θtilt calculated with the equation (1) is 0.29146rad. As described above, it is possible to calculate the sufficiently precise tilt angle with the equation (1). This is applicable to the pan angle.

As described above, by touching the part of the touch panel 71 on the hook image 21 G on the screen 70 Ga of the monitor 70 (see FIG. 4 ), the distances Δy and Δx are calculated, and the camera inclination angle calculation unit 65 calculates the inclination angle and the pan angle with the equations (1) and (2). Therefore, the inclination angle detection sensor to detect the inclination angle of the monitoring camera 32 is not required.

The work region calculation unit 66 calculates, based on the load weight of the suspended load, the work region line indicating the region where the suspended load is movable, and calculates, based on the inclination angle (the tilt angle and the pan angle) of the monitoring camera 32 , which is calculated by the camera inclination angle calculation unit 65 , the position of the work region line on the image on the monitor 70 corresponding to the work region line. As illustrated in in FIG. 4 , the image combining unit 67 combines a work region line UI on the position on the image corresponding to the position of the work region line calculated by the work region calculation unit 66 and captured by the monitoring camera 32 , and displays the combined image on the screen 70 Ga of the monitor 70 .

According to the first embodiment, the attitude angle detection sensor to detect the attitude of the monitoring camera 32 is not required, and it is possible to display, based on the inclination angle of the monitoring camera 32 calculated by the camera inclination angle calculation unit 65 , the precise work region line UI on the monitor 70 and to provide the inexpensive camera attitude detection device 100 and work region line display device 120 .

Furthermore, when the hook 21 swings and the moving hook image 21 G is displayed on the screen 70 Ga of the monitor 70 as illustrated in FIG. 7 , it is assumed that the center position of the figure formed by a movement locus I of the hook image 21 G is the position of the hook image 21 G, and the center position of the figure is touched. Alternatively, the center positions of a plurality of the hook images 21 G may be calculated by the image processing.

FIG. 8 illustrates another example of the camera attitude detection device 100 in which an image processing unit 130 calculates a height h 1 .

As illustrated in FIG. 9 , the image processing unit 130 includes a hook image extraction unit 131 to extract a hook image from the image captured by the monitoring camera 32 , an area calculation unit 132 to calculate the area of the hook image extracted by the hook image extraction unit 131 , and a height calculation unit 133 to calculate the height h 1 from the area (size) calculated by the area calculation unit 132 .

Since the area of the hook image becomes smaller as the height h 1 increases, the height h 1 is calculated by using this relation.

When the camera is zoomed, the zoom magnification is calculated from the size of the hook image and the length of the wire image displayed on the monitor 70 , and the height h 1 is calculated from the zoom magnification and the area of the hook image. The ratio of the hook area, in which the length of the wire 25 displayed on the monitor 70 is set as a parameter, has been stored in a memory, which is not illustrated, and the length of the displayed wire 25 is calculated, whereby the zoom magnification is calculated from the zoom magnification corresponding to the length.

FIG. 10 illustrates another example of a camera attitude detection device 160 in which an image processing unit 150 calculates the hook position.

As illustrated in FIG. 11 , the image processing unit 150 includes a hook image extraction unit 151 to extract the hook image from the image captured by the monitoring camera 32 and a center position calculation unit 152 to calculate the center position of the hook image extracted by the hook image extraction unit 151 as the hook position. The other configuration is similar to the camera attitude detection device 100 illustrated in FIG. 2 , and the description thereof is omitted.

The hook image extraction unit 151 calculates the image by image processing, such as a region growing method, or a pattern matching.

In the region growing method, the lines having a different brightness difference are calculated as boundaries of the hook from the hook position where the screen of the monitor 70 is touched, and the figure center of the figure enclosed by the boundaries is set as the hook position.

In the pattern matching, a hook pattern for each zoom magnification is stored in advance, and the position where the pattern coincides with an actual hook image obtained by performing scan processing to the screen is calculated, whereby the position is set as the hook position.

When the hook image is extracted with an image processing method, such as the pattern matching, the touch panel 71 is not necessarily required

Second Embodiment

FIG. 12 is a block diagram illustrating a configuration of a work region line display device 200 of a second embodiment.

The work region line display device 200 includes a work region calculation unit 66 of a controller 260 and a camera attitude detection device 210 .

[Camera Attitude Detection Device]

The camera attitude detection device 210 includes a camera unit 30 , a boom attitude detection sensor 50 , the controller 260 (except the work region calculation unit 66 ), a monitor 70 , and a touch panel 71 .

[Controller]

The controller 260 includes a memory 201 in which a movement locus of a hook 21 is stored in association with a derricking angle of a telescopic boom 16 and a zoom magnification of a monitoring camera 32 , a reading means 202 to read the movement locus stored in the memory 201 based on the derricking angle of the telescopic boom 16 and the zoom magnification of the monitoring camera 32 , an intersection point calculation unit 203 to calculate an intersection point V 1 of a read movement locus K 1 (see FIG. 13 ) and a radial direction line N 1 , a hook position calculation unit 63 , a shift amount calculation unit 264 , a camera inclination angle calculation unit 265 , a motor control unit 61 , and an image combining unit 67 .

[Memory]

When the monitoring camera 32 faces directly downward, the movement locus of the hook 21 displayed on the screen of the monitor 70 when the hook 21 is raised or lowered is stored in the memory 201 in association with the derricking angle of the telescopic boom 16 and the zoom magnification of the monitoring camera 32 .

[Intersection Point Calculation Unit]

The intersection point calculation unit 203 calculates the intersection point V 1 of the movement locus K 1 and the radial direction line N 1 passing through the hook image 21 G as illustrated in FIG. 13 . The radial direction line N 1 is parallel to a line projected on the horizontal plane passing through the center position of the hook 21 in the extending direction of the telescopic boom 16 and is the line passing through the center position of the hook 21 . In other words, when the extending direction of the telescopic boom 16 is the perpendicular direction of a screen 70 Ga of the monitor 70 , a line extending in the perpendicular direction passing through the hook image 21 G is the radial direction line N 1 .

[Shift Amount Calculation Unit]

The shift amount calculation unit 264 calculates a separated distance ΔD between the position of the hook image 21 G and the intersection point V 1 .

[Camera Inclination Angle Calculation Unit]

The camera inclination angle calculation unit 265 calculates the inclination angle θ of the monitoring camera 32 (the inclination angle in the radial direction) from the separated distance ΔD and the distance h 1 (see FIG. 5 ) in the height direction from an optical center of the monitoring camera 32 to the hook position based on the following equation (4).

θ=tan −1 (Δ D/h 1)  (4)

This is the same equation as the equation (1), as illustrated in FIG. 5 , a position B of the screen 70 Ga is the position (the intersection point V 1 ) on the movement locus K 1 illustrated in FIG. 13 , and a position A of the screen 70 Ga is the position of the hook image 21 G. Furthermore, the direction joining the position A and the position B is the extending direction of the telescopic boom 16 , and the distance Δy between the positions A and B is ΔD illustrated in FIG. 13 . Therefore, the inclination angle θ of the monitoring camera 32 can be calculated with the equation (4).

The embodiment is an effective method for the monitoring camera 32 which downwardly follows the derricking motion of the telescopic boom 16 only in the tilt direction.

The other configuration is similar to the first embodiment, and the description thereof is omitted.

Third Embodiment

In a third embodiment, an image captured by a monitoring camera 32 provided at a tip of a telescopic boom 16 is displayed on a monitor 370 (see FIG. 16 ), the direction of the monitoring camera 32 is operated by pan and tilt operation, and a hook 21 is positioned at a predetermined position on a screen 370 G of the monitor 370 , whereby an attitude angle of the monitoring camera 32 is detected.

FIGS. 14 and 15 are block diagrams illustrating a configuration of a work region line display device 300 of the third embodiment. FIG. 15 detailedly illustrates the configuration inside a controller 360 illustrated in FIG. 14 , and illustrates the work region line display device 300 classified into four components of a camera attitude detection device 310 , a coordinate position calculation unit 364 , a work region calculation unit 365 , and an image combining unit 366 .

The camera attitude detection device 310 includes a camera unit 30 , a boom attitude detection sensor 50 , the controller 360 , the monitor 370 to display the image captured by the monitoring camera 32 , a pan switch SW 1 , and a tilt switch SW 2 .

On the screen 370 G of the monitor 370 , as illustrated in FIG. 16 , a rectangular frame Ma is displayed in the center part of the screen.

[Controller]

As illustrated in FIG. 15 , the controller 360 includes a motor control unit 61 , an attitude angle calculation unit (calculation means) 363 , a coordinate position calculation unit (coordinate position calculation means) 364 , a work region calculation unit (work region calculation means) 365 , and an image combining unit 366 .

The motor control unit 61 controls a pan motor 33 and a tilt motor 34 based on the signal from the pan switch SW 1 and the tilt switch SW 2 .

The attitude angle calculation unit 363 calculates the attitude angle of the monitoring camera 32 based on an unwound amount of a winch output from the boom attitude detection sensor 50 , the length of the telescopic boom 16 and an offset amount W 1 which will be described later.

The coordinate position calculation unit 364 calculates, based on the attitude angle calculated by the attitude angle calculation unit 363 and the various detection signals of the telescopic boom 16 output from the boom attitude detection sensor 50 , a coordinate position at each position on the captured image in a crane coordinate system where a swivel center position of the telescopic boom 16 is set as an origin.

The work region calculation unit 365 calculates, based on a load weight of a suspended load, a work region line indicating the region where the suspended load is movable.

The image combining unit 366 combines the work region line calculated by the work region calculation unit 365 on the image captured by the monitoring camera 32 mapped on the coordinate position calculated by the coordinate position calculation unit 364 , and displays the combined image on the monitor 370 .

Then, the coordinate position calculation unit 364 and the work region calculation unit 365 constitute the work region calculation device 380 to calculate the precise position of the work region line on the image.

[Theory]

As illustrated in FIG. 17 , it is assumed that a rotating shaft 32 J of the monitoring camera 32 and a center D 1 of a sheave 23 have an offset amount of W 1 in the left and right directions (in the case in which an offset amount W 2 in the perpendicular direction can be ignored). Furthermore, it is assumed that the height from the ground to the center D 1 of the sheave is H 2 , that the length from the center D 1 of the sheave to the hook block 19 is La, and that the inclination of the monitoring camera 32 when an optical axis of the monitoring camera 32 is turned to the hook 21 , that is, the inclination angle of the monitoring camera 32 with respect to the perpendicular line when the optical axis of the monitoring camera 32 is turned to the hook 21 is θ. Then, it is assumed that a work radius of the telescopic boom 16 from a swivel center position O of the telescopic boom 16 is Ra, that the distance between the work radius Ra and a position Pa on the ground which is the image center when the monitoring camera 32 is titled is ΔRa, and that the length joining the rotating shaft 32 J of the monitoring camera 32 and an optical center position Q 1 is negligibly small with respect to the height H 2 , then the distance ΔRa can be calculated with the following equation.

Δ Ra=H 2 tan θ− W 1

The inclination θ of the monitoring camera 32 can be calculated from the length La and the offset amount W 1 . The length La is calculated from an unwound amount of a wire 25 . The inclination of the monitoring camera 32 in the pan direction is similarly calculated.

The height H 2 can be calculated from the length and derricking angle of the telescopic boom 16 . Note that, since the camera rotating shaft 32 J and the position of the center D 1 of the sheave with respect to the telescopic boom 16 are known, the offset amount W 1 can be calculated according to the derricking angle of the telescopic boom 16 .

The position on the ground corresponding to the center position of the image on the monitor 370 is Pa, and the swivel center position O of the telescopic boom 16 can be calculated from the position Pa with an error ΔRa and the work radius Ra. Similarly, the swivel center position O in the pan direction is calculated.

Then, the work region line can be drawn at the position of a distance Rb (the distance indicating the work region range) setting the swivel center position O as the center.

Here, since the center position of the image indicates the position Pa on the ground and the height H 2 is known, the coordinate position on the ground can be mapped on the coordinate position on the image. In other words, the coordinate position in the crane coordinate system where the swivel center position of the telescopic boom 16 is set as an origin is mapped on each position on the captured image.

Thus, it is possible to superimpose the work region line on the precise position of the image and display the superimposed image on the monitor 70 .

Note that, as illustrated in FIG. 17A , although the offset amount W 2 is also generated in the perpendicular direction due to the derricking angle of the telescopic boom 16 , the offset amount W 2 can be also calculated from the derricking angle, the inclination of the monitoring camera 32 can be geometrically calculated.

That is, the following equation is established:

Δ Ra=H 1′ tan θ− W 1, H 1′= H 2− W 2

where H 1 ′ is the height from the ground to the camera rotating shaft 32 J.

With the equation, the inclination θ of the monitoring camera 32 can be calculated from the length L 1 and the offset amounts W 1 and W 2 . The inclination of the monitoring camera 32 in the pan direction is similarly calculated.

Furthermore, as illustrated in FIG. 17B , when the turning shaft of the monitoring camera 32 is provided at the same shaft as the turning shaft of the sheave, the offset amounts W 1 and W 2 are not generated, and it is not necessary to consider the offset amount.

[Operation]

Next, the operation of the work region line display device 300 which is configured as described above will be described.

As illustrated in FIG. 16 , the operator operates the pan switch SW 1 and the tilt switch SW 2 and inclines the monitoring camera 32 so that the hook image 21 G is continuously fitted in the center frame Ma on the screen 370 G of the monitor 370 .

When the controller 360 calculates the actual load weight of the suspended load or the operator inputs the load weight, the work region calculation unit 365 (see FIG. 15 ) calculates the work region line based on the actual load weight or input load weight.

On the other hand, the attitude angle calculation unit 363 calculates a suspended length La of the hook 21 illustrated in FIG. 17 from the detection signal output from the boom attitude detection sensor 50 , that is, from the wound-out amount of the wire 25 (see FIG. 1 ) unwound by the winch and the length of the telescopic boom 16 , and calculates, from the length La and the offset amount W 1 , the inclination angle θ (the angle in the pan or tilt direction) of the monitoring camera 32 with respect to the perpendicular line.

In other words, the attitude angle calculation unit 363 calculates the inclination angle θ of the monitoring camera 32 from tip position information on the telescopic boom 16 (the position calculated from the length and derricking angle of the telescopic boom 16 ) and position information on the hook 21 (the offset amount W 1 and the length La).

The coordinate position calculation unit 364 calculated the height H 2 illustrated in FIG. 17 based on the detection signal output from the boom attitude detection sensor 50 , that is, the length and derricking angle of the telescopic boom 16 , and further calculates, from the height H 2 and the inclination angle θ of the monitoring camera 32 , the coordinate position corresponding to each position on the captured image in the crane coordinate system where the swivel center position of the telescopic boom 16 is set as an origin.

As illustrated in FIG. 18 , the image combining unit 366 combines (superimposes) a work region line U 2 calculated by the work region calculation unit 365 on the image corresponding to the coordinate position in crane coordinate system calculated by the coordinate position calculation unit 364 , and displays the combined image on the monitor 370 .

In the third embodiment, an attitude angle detection sensor to detect the attitude of the monitoring camera 32 is not required, and it is possible to obtain an effect similar to the first embodiment.

In the third embodiment, although the hook image 21 G deviates from the frame Ma on the screen 370 G of the monitor 370 due to the derricking motion of the telescopic boom 16 , or raising or lowering the suspended load according to a work, it is assumed that the operator operates the pan switch SW 1 or the tilt switch SW 2 so as to continuously fit the hook image 21 G in the frame Ma on the screen 370 G of the monitor 370 . Then, the attitude angle calculation unit 363 and the coordinate position calculation unit 364 read every detection signal output from the boom attitude detection sensor 50 , calculate the coordinate position corresponding to the inclination angle θ and each position on the captured image in the crane coordinate system, and rewrite the work region line U 2 in real time.

Therefore, during the hook image 21 G is fitted in the frame Ma on the screen 370 G of the monitor 370 even while the suspended load is being moved, it is possible to accurately display the work region line U 2 on the screen 370 G of the monitor 370 .

Fourth Embodiment

FIG. 19 illustrates a configuration of a work region line display device 1200 of a fourth embodiment. In the fourth embodiment, a reference setting switch (setting means) SW 4 and a memory 1201 are provided.

When an operator operates a pan switch SW 1 or a tilt switch SW 2 and a hook image 21 G is fitted in a frame Ma on a screen 370 G of a monitor 370 (see FIG. 18 ), the operator turns the switch SW 4 on. When the switch SW 4 is turned on, an attitude angle calculation unit 363 of a controller 1260 illustrated in FIG. 20 calculates, similarly to the third embodiment, an inclination angle of an monitoring camera 32 (the angle in the pan and tilt direction) based on a detection signal detected by a boom attitude detection sensor 50 .

Furthermore, when the switch SW 4 is turned on, an wound-out amount of a hook 21 and an attitude of a telescopic boom 16 (the length, derricking angle, and swivel angle of the telescopic boom 16 ) which are the detection signal detected by the boom attitude detection sensor 50 , and the inclination angle of the monitoring camera 32 (the angle in the pan and tilt direction) calculated by the attitude angle calculation unit 363 at this time are stored in the memory 1201 as a reference value.

Furthermore, by turning the switch SW 4 on, a calculation unit, which is not illustrated, of the controller 1260 calculates, similarly to the third embodiment, an actual load weight. Then, a work region calculation unit 365 illustrated in FIG. 20 calculates a work region line U 2 (see FIG. 18 ) based on the actual load weight, and the inclination angle θ of the monitoring camera 32 and the attitude of the telescopic boom 16 which are stored in the memory 1201 .

On the other hand, a coordinate position calculation unit 364 calculates, similarly to the third embodiment, the coordinate position corresponding to each position on the captured image in the crane coordinate system. Furthermore, an image combining unit 366 combines the work region line U 2 calculated by the work region calculation unit 365 being mapped on the coordinate position in crane coordinate system calculated by the coordinate position calculation unit 364 , and displays the combined image on the monitor 370 (see FIG. 18 ).

In other words, in the fourth embodiment, it is assumed that the hook image 21 G is being fitted in the frame Ma on the screen 370 G of the monitor 370 after the switch SW 4 is turned on, and the work region line U 2 is continuously displayed. In the fourth embodiment, the pan switch SW 1 or the tilt switch SW 2 is not operated.

Due to the change of the attitude of the telescopic boom 16 , and raising or lowering the hook 21 by the winch, when the hook image 21 G deviates by a predetermined amount from the frame Ma on the screen 370 G of the monitor 370 , that is, when the wound-out amount of the hook 21 and the attitude data of the telescopic boom 16 (the length and derricking angle of the telescopic boom 16 ), which are detected by the boom attitude detection sensor 50 , are shifted by a predetermined value or more from a reference value stored in the memory 1201 , it is determined that the error of the positional shift with respect to the image displaying the work region line U 2 is large, and an error display is performed. The error display is performed by, for example, displaying characters on the monitor 370 , changing the color of the frame Ma, or flickering or removing the work region line U 2 .

By performing the error display, the operator can recognize that the displayed work region line is wrong.

According to the fourth embodiment, when the operator operates the telescopic boom 16 and the winch after positioning the hook image 21 G in the frame Ma on the screen 370 G, the controller 1260 can determine whether the hook image 21 G is positioned in the frame Ma on the screen 370 G, that is, at a predetermined position of the screen 370 G. Furthermore, it is possible to obtain an effect similar to the third embodiment.

Fifth Embodiment

A work region line display device (not illustrated) of a fifth embodiment has a configuration similar to the work region line display device 1200 of the fourth embodiment, and the description thereof is omitted.

Thereafter, when an operator operates a pan switch SW 1 or a tilt switch SW 2 , an error of a work region line U 2 becomes large, and an error display is performed.

Since the operator operates the pan switch SW 1 or the tilt switch SW 2 and thereby the error of the work region line U 2 becomes large, the work region line display device of the fifth embodiment performs the error display. Furthermore, the operator is informed in advance not to operate the pan switch SW 1 or the tilt switch SW 2 after turning a switch SW 4 on.

Furthermore, when the winch is only driven after the switch SW 4 is turned on, only a hook 21 is raised or lowered, and an hook image 21 G deviates from a frame Ma on a screen 370 G of a monitor 370 . However, the work region line U 2 is continuously displayed at the precise position on the screen 370 G of the monitor 370 as long as the pan switch SW 1 or the tilt switch SW 2 is operated.

Unless the error display is performed by turning the pan switch SW 1 or the tilt switch SW 2 on, the operator can operates the crane under the precise work region line display.

According to the fifth embodiment, when the operator operates the telescopic boom 16 and the winch after positioning the hook image 21 G in the frame Ma on the screen 370 G, the controller 1260 can determine whether the hook image 21 G is positioned in the frame Ma on the screen 370 G, that is, at the predetermined position on the screen 370 G. Furthermore, it is possible to obtain an effect similar to the third embodiment.

Sixth Embodiment

A work region line display device (not illustrated) of a sixth embodiment have a configuration similar to the work region line display device 1200 of the fourth embodiment, and the description thereof is omitted.

When a pan switch SW 1 or a tilt switch SW 2 is operated after a switch SW 4 is turned on, the work region line display device of the sixth embodiment considers the operation as the operation to fit a hook image 21 G (see FIG. 18 ) on a monitor 370 (see FIG. 19 ) in a frame Ma, sequentially calculates, similarly to the fourth embodiment, a work region line U 2 , and rewrites the work region line U 2 displayed on the monitor 370 in real time.

In the sixth embodiment, an operator is informed in advance to operate the pan switch SW 1 or the tilt switch SW 2 so as to fit the hook image 21 G in the frame Ma after the switch SW 4 is turned on.

The operator can recognize that the precise work region line is displayed by performing the operation other than pan/tilt operation of the camera or performing the pan/tilt operation to fit the hook 21 in the frame Ma.

In any of the above described third embodiment to sixth embodiment, the inclination angle θ of the monitoring camera 32 has been calculated from the length La and the offset amount W 1 illustrated in FIG. 17 . However, the inclination angle of the monitoring camera 32 may be calculated from the position on the image of the hook image 21 G and the length La by the image processing. In this case, the hook image 21 G is not required to be fitted in the frame Ma. Furthermore, the frame Ma is not required to be displayed.

Furthermore, the pan motor 33 and the tilt motor 34 may be controlled so as to automatically fit the hook image 21 G in the frame Ma by the image processing.

With the sixth embodiment, an effect similar to the third embodiment can be obtained.

Seventh Embodiment

FIG. 21 illustrates a configuration of a work region line display device 1500 of a seventh embodiment. The work region line display device 1500 includes a monitoring camera 1532 which does not have a pan/tilt function. The monitoring camera 1532 is provided in a housing 31 (see FIG. 1 ), and the housing 31 is mounted on a tip of a top boom 16 C through a damper (not illustrated), whereby the monitoring camera 1532 faces directly downward by its own weight.

When the monitoring camera 1532 faces directly downward, a locus FE of a hook image 21 G when a hook 21 is raised or lowered is combined and displayed on a screen 370 G of a monitor 370 as illustrated in FIG. 22 .

When the monitoring camera 1532 does not face directly downward due to the action of the damper, the hook image 21 G deviates from the locus FE, and it is recognized that the displayed work region line U 2 is incorrect.

When a rotating shaft 32 J of the monitoring camera 1532 and a center D 1 of a sheave are offset as illustrated in FIG. 17 , the position of the locus FE is changed according to the derricking angle of a telescopic boom 16 . Therefore, as illustrated in FIG. 23 , the position of the locus FE may be changed to FEa according to the derricking angle. In this case, the work region line U 2 is changed to a precise work region line Ua according to the derricking angle.

Note that, although it is described that the present embodiment does not have the pan/tilt function, the pan/tilt function is provided in the monitoring camera 1532 , and the monitoring camera 1532 is paned or tilted so as to position the hook image 21 G on the above described loci FE and FEa, whereby the monitoring camera 1532 can face directly downward, and the work region lines U 2 and Ua displayed on the monitor 370 are the precise work region lines.

With the above configuration, the operation to fit the hook image 21 G on the monitor 370 in the frame Ma is not required, and it is only required to operate the monitoring camera 1532 so as to coincide with the locus FE, whereby the operation is facilitated.

In either of the above described third embodiment to seventh embodiment, although the frame Ma is displayed in the center of the screen 370 G of the monitor 370 , the frame Ma is necessarily displayed in the center of the screen 370 G, and furthermore, the frame Ma may not be displayed. For example, a cross mark may be displayed.

The present invention is not limited to the above described embodiments, and modifications or additions of the design can be made without departing from the gist of the invention according to each claim in the claims.