JP2593166B2 - Seedling row detecting device in agricultural work machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an agricultural work machine such as a rice transplanter which is already planted in a field and is arranged in a substantially straight line. The present invention relates to a structure of a planting row detecting device for automatic steering that enables the vehicle to travel.

[Conventional technology]

Conventionally, when planting seedlings in a field with a rice transplanter, the rice transplanter is provided with planting mechanisms at appropriate intervals on the left and right in the traveling direction, and the seedling mat on the seedling table is rotated by the planting mechanism that rotates up and down as the rice transplanter advances. Are planted in the field scene while dividing them by the number of plants as appropriate, so that in the field scene, at the appropriate seedling planting intervals along the traveling direction of the rice transplanter, It is well known that a plurality of rows are planted at appropriate intervals in a direction.

Japanese Patent Application Laid-Open No. 62-61509 discloses a prior art of an automatic steering device that enables a rice transplanter to run in a direction substantially parallel to a seedling row already planted in a field. With the color video camera obtained, an appropriate range of the planted seedling row in the adjacent portion is imaged, and the imaged screen information is binarized to extract a region corresponding to each planted seedling location. A straight line is approximately calculated from the row composed of the plurality of regions by a process such as Hough transformation, and a virtual straight line on this calculation and an arbitrary reference line such as a vertical and horizontal center line of the imaging screen and a lateral shift and inclination with respect to a reference point are calculated. It has been proposed to execute the steering control of the aircraft so that the deviation falls within a certain allowable range.

[Problems to be solved by the invention]

In the prior art, since only the field scene and the existing seedling row are imaged on the imaging screen of the imaging means, the gap and the mounting angle of the mounting position of the imaging means itself with respect to the body of the rice transplanter cannot be detected. .

Therefore, when controlling the operation to keep the inclination and lateral displacement of the aircraft with respect to the existing seedling row within a certain range,
For example, the inclination of the reference line of the imaging screen with respect to the left and right center lines of the aircraft and the deviation of the reference point of the imaging screen with respect to the left and right center lines of the aircraft are input in advance as data, while the vertical and horizontal center points and the vertical center line of the imaging screen are input. It is necessary to recalculate the calculated inclination and lateral displacement of the virtual line with respect to the reference as the inclination and deviation with respect to the data, and there is a problem in that the image processing operation time for automatic steering control becomes longer.

Further, since the image pickup means can be attached to an arbitrary position of the body in an arbitrary posture, the data is used when there is an error in the attachment position and the attachment angle or when readjustment after replacing the image pickup means. Entering each one was time-consuming and virtually impossible.

In addition, since the management machine for applying fertilizer or spraying the chemical at an appropriate time after the seedling planting operation may perform the operation while proceeding along the already planted seedling row, the agricultural machine may be automatically operated. When the steering device is mounted, the same problem as described above occurs.

An object of the present invention is to solve this problem.

[Means for solving the problem]

Therefore, the present invention provides an agricultural work machine such as a rice transplanter running in a field, with an imaging means for imaging a plurality of planted seedling locations in a planted seedling row already planted along the side thereof, and A virtual line of a planted seedling row is determined by binarizing means for specifying each planted seedling portion as an area from image information and virtual line calculating means for approximating a virtual line from the binarized row of each target area. On the other hand, in the imaging screen by the imaging means, an image of a part of the body of the agricultural work machine for setting as a reference for the virtual line of the planted seedling row is taken, and an error between this reference and the virtual line is calculated. This is a configuration provided with an image processing device.

[Functions and effects of the invention]

According to this configuration, if an arbitrary position of a part of the body of the agricultural work machine imaged in the imaging screen is used as a reference, even if the mounting position or the mounting angle of the imaging unit itself with respect to the body of the farm work machine is changed, It is sufficient to calculate the inclination and the difference between the virtual line and the reference based on the reference in the imaging screen, and the deviation of the calculated virtual line from the reference and the inclination with respect to the reference can be uniquely specified. Positioning and mounting work is extremely simple.

Then, as in the case where the body is not imaged on the imaging screen, once the virtual line is calculated based on the fixed reference of the imaging screen, the virtual line is calculated based on the data of the geometrical relationship between the imaging means and the body. The calculation time for image processing can be greatly reduced as compared to executing the calculation for correcting the inclination of the camera, and it is not necessary to consider the mounting error of the imaging means, and the steering control can be performed more accurately. It has the effect of being able to do it.

〔Example〕

Hereinafter, an embodiment in which the present invention is applied to a rice transplanter will be described. In FIG. 1, reference numeral 1 denotes a traveling body supported by front wheels 3, 3 on the front left and right sides of a frame 2 and rear wheels 4, 4 on the rear left and right sides. A multi-row planting seedling plant 7 including a seedling mounting table 5 and a plurality of planting mechanisms 6 is mounted on a rear portion of the traveling body 1 via a link mechanism 8 so as to be able to move up and down.

Engine 9 mounted on the upper surface of frame 2 of traveling body 1
Is transmitted to the front and rear wheels 3 and 4 via a clutch 10 and a transmission case 11, while the transmission case 1
Power is transmitted to the seedling plant 7 via a PTO shaft 12 protruding from 1. Reference numeral 13 denotes an actuator for ON / OFF of the clutch 10, 14 denotes an actuator for traveling speed change, and 15 denotes an actuator for PTO shaft speed change.

On the upper surface of the traveling body 1, a steering gear box 17 is provided in front of a control seat 16, and at the upper end of a steering column 18 erected from the steering gear box 17,
Steering shaft inserted into the steering column 18
A steering handle 20 for 19 is installed.

Reference numeral 21 denotes a left and right longitudinal transmission case in which front wheels 2, 2 are mounted via knuckles 22, 22 on both left and right ends and a power transmission mechanism from the transmission case 11 is housed inside.
Is connected via a bracket 21a having a U-shape in plan view to be attached thereto and a swing shaft 21c rotatably supported by a support member 21b at the center of the lower surface of the frame 2 at the left and right. It is configured to be able to.

The steering device 26 has an L-shaped steering arm 24 in a plan view mounted on a rotation fulcrum shaft 23 erected from one side of the transmission case 15 so as to be horizontally rotatable, and a pair of left and right tie rods connected to the steering arm 24. 25, 25, a hydraulic cylinder 26, a steering control valve 27, and a pitman arm capable of swinging back and forth of a steering gear box 7 for operating the steering control valve 27.
Consists of 28.

One end of each of the pair of left and right tie rods 25, 25 is connected to an arm portion 24a of the steering arm 24 extending in the front-rear direction of the frame 4 via a ball joint, and the two tie rods 25, 25 are substantially attached to the transmission case 15. Running aircraft 1 along
Of the knuckle 22 and 2
It is swingably connected to knuckle arms 29, 29 extending forward from 2.

A control valve 27 is provided on a support shaft 30 of an arm portion extending inward from the steering arm 24 toward the side surface of the frame 2.
Is connected backward through a ball joint, while the steering control valve
Link the spool at the rear end of 27 with the pitman arm 28
Connect via 31.

The rear end of a hydraulic cylinder 26 disposed substantially parallel to the outer surface of the frame 2 is connected to the support shaft 30 via a ball joint, while the front end of the piston rod 26a is connected to the frame via a ball joint. 2 Connected to the bracket horizontal shaft 32 projecting from the outer surface.

While the steering control valve 27 and the hydraulic cylinder 26 are each connected by a hydraulic hose, hydraulic pressure is sent from a hydraulic pump 33 driven by the engine 5 to an electromagnetic solenoid type control valve 27.

The spool of the control valve 27 is moved forward and backward by the pitman arm 28 that swings in accordance with the rotation angle of the steering handle 10 to move the piston rod in the hydraulic cylinder 26.
26a is moved in and out, and the directions of the left and right front wheels 2, 2 are changed in accordance with the rotation of the steering arm 24.

The hydraulic cylinder 26 is also controlled by an electromagnetic solenoid type steering control valve 34 operated by an automatic steering / running central control device 35 that outputs an output signal in accordance with a signal from a planting seedling detection device 37 described later. When driven, the steering angle of the front wheel 3 is executed by detecting the turning angle of the steering arm 24 with a potentiometer 36 attached to the turning fulcrum shaft 23.

Incidentally, an actuator 13 for ON / OFF of the clutch 10,
Actuator 14 for traveling speed change, actuator 1 for PTO shaft speed change
5 is also operated by the central controller 35.

The planting seedling row detection device 37 includes an imaging unit 40 for imaging the target.
And an image processing device 41 for processing a captured image and outputting necessary information (data).

The imaging means 40 can image a detection target like a color video camera and output imaging information of the imaging screen 42 as an electric signal, and can be a two-dimensional MOS imaging device or a two-dimensional CCD.
In the image pickup means 40 having an image pickup device, an image formed through a lens is sensed by each photoelectric element arranged in a two-dimensional array on the image forming surface, and information on the image pickup screen 42 is output as an electric signal. You can do it.

Hereinafter, a display element for forming one imaging screen 42 is referred to as a pixel. In other words, each element obtained by dividing one imaging screen into elements having a small area is a pixel. In the two-dimensional image sensor, each image sensor corresponds to one pixel,
Normally, one screen is sampled using 256 × 256 pixels.

Then, in this embodiment, in order to set a reference described later, a part of the body, in particular, a part of the front wheel 3 on the side close to the adjacent planted seedling row is set in the imaged screen 42 by the imaging means 40. Then, the direction of the imaging means 41 is set by the sensor posture correcting means 43 such as a step motor.

The image processing device 41 reads the data of the imaging screen 42 imaged by the imaging means 40, and after binarization for extracting the seedling locations (NAE) planted from the data from the mud surface of another field, The position of each binarized target area (A) is specified, and then the center or the center of gravity of the specified target area (A) is calculated by a predetermined calculation method using software incorporated in the image processing device 41. From the data, the virtual line K of the planting seedling row is determined by using a virtual line calculating means of a straight line approximation or a curve approximation by a Hough transform, a least square method, or the like, and the inclination and the lateral deviation of the virtual line K with the reference are determined. The deviation (error) is calculated.

In the present embodiment, when a captured image is composed of a color image, RGB color system [red (R), green (G), and blue (B) color light is used as primary color light, and white is obtained by adding light. To extract the features of the field scene from the signals of the respective red, green and blue color components, and output the signal of the green (G) component with respect to the sum (R + G + B = 1) of the signal outputs of the three color components When the ratio is equal to or greater than a predetermined value, the binarization process is performed in which the region (A) is identified as a seedling, and the area (A) is segmented from another portion of the screen 42 and specified.
In this binarization process, the area 3A of the front wheel 3 is also specified.

In addition, binarization may be executed by a color difference process of judging a portion where the color difference image data (GB) obtained by subtracting the blue component from the green component of the color signal in the image is equal to or more than a predetermined value as a seedling.

Next, a so-called Hough transform operation device will be described as one of virtual line calculation means for specifying a virtual line K of a planted seedling row from a plurality of areas (A) specified by the binarization. Storing the coordinates of the areas (A) corresponding to the plurality of planted seedling locations (NAE) in the image information, and calculating a line segment passing through the coordinates for each coordinate of each area (A);
A process (Hough transform process) for defining the plurality of line segments as a Hough value (ρ) and an angle (θ0) from a predetermined expression expressed in a polar coordinate system is performed, and the frequency of taking the same Hough value (ρ) is two-dimensional. It is counted as a histogram, and the line segment of the planted seedling row is specified from the Hough value (ρ) and the angle (θ0) that are the maximum values.

As another virtual line calculation means, as is generally well known, there is a method using a virtual line determination calculation device based on least square error estimation.

In other words, this approach, a set of a plurality of regions {coordinates (Xi, Yi) [i = 1,2,3, ‥‥, N) } when a given, determined function F (x) = a0 + a1x + a2x 2 + a3x ³ + ‥‥ + anx ⁿ , Is reduced to the problem of finding a function F (x) that minimizes .in this case, the function F (x) may be assumed in advance to be a multi-dimensional curve such as a straight line or a quadratic curve.

Next, when calculating the error such as the inclination and the lateral shift between the virtual line K and the reference obtained in this manner, the front wheel 3 in the screen imaged by the imaging means 40 as shown in FIG.
Is defined as the reference point O with the upper angle of the area 3A specified by the binarization as shown in FIG. 6, and at this time, the coordinates (0, 0), the inclination angle (θ) of the virtual line K is calculated using the Y axis (vertical axis) passing through the coordinates as a reference line, while the X axis (horizontal axis) passing through the reference point O and the virtual line K Is calculated as the distance from the intersection with the reference point O to the reference point O.

Then, an image processing apparatus according to the flowchart of FIG.
In the calculation of 41, it is determined whether or not the inclination angle (θ) and the lateral displacement distance (δ) of the virtual line K are within the allowable range of the error.
Output signal to actuate the electromagnetic solenoid of the steering control valve 34, and the steering arm in the steering mechanism
The corrective steering is performed by driving the hydraulic cylinder 26 that changes the rotation angle of the 24, and the automatic steering control is executed so as to fall within a predetermined error tolerance. In this case, it is determined whether or not the front wheel 3 has a steering angle that inclines rightward or leftward with respect to the traveling direction by a potentiometer 36 that detects the rotation angle of the steering arm 24. It can be used for convergence control that progresses in parallel with the row of seedlings.

A part of the front wheel 3 on the side close to the adjacent planting seedling row is put in an image screen 42 by the imaging means 40, and the front wheel 3
When the area 3A specified by the binarization is used as a reference, the tilt angle (θ1) in the imaging screen 42 by steering as shown in FIG.
Changes along the straight line 3 along the vertical edge of the area 3A.
If it is configured to grasp the change of A 'as appropriate with time, data can be output in consideration of the temporal change of the angle (θ2) between the virtual line K and the straight line 3A'.
The potentiometer 36 can be eliminated.

[Brief description of the drawings]

1 is a plan view of a riding type rice transplanter, FIG. 2 is a side view, FIG. 3 is a plan view of a main part of a steering device, and FIG. 4 is steering and traveling. FIG. 5 is a block diagram of an automatic control device and an operation explanatory diagram including a hydraulic circuit, FIG.
FIG. 7 is an explanatory diagram of a binarized imaging screen, FIG. 7 is an explanatory diagram of an imaging screen of another embodiment, and FIG. 8 is a schematic flowchart. 1 ... traveling body, 2 ... frame, 3,4 ... wheels, 5 ...
… Seedling stand, 6… Planting mechanism, 7… Seedling plant, 8… Link mechanism, 9… Engine, 11… Mission case,
17 ... steering gear box, 20 ... steering handle, NAE ... planting seedling location, K ... virtual line, 23 ... rotating fulcrum shaft, 24 ... steering arm, 26 ... hydraulic cylinder, 34 ... steering Control valve, 35 central control device, 36 potentiometer, 40 imaging means, 41 image processing device, 42 imaging screen, A, 3A area.

Claims (1)

(57) [Claims] An image pickup means for picking up an image of a plurality of planted seedling locations in a row of planted seedlings already planted along a side thereof is provided on an agricultural work machine such as a rice transplanter running on a field. A virtual line of the planted seedling row is determined by binarizing means for specifying each planted seedling location as an area from the image information and virtual line calculating means for approximating a virtual line from the binarized row of the target area. On the other hand, during the imaging screen by the imaging means,
An agricultural work, comprising: an image processing device that captures an image of a part of a body of a farm working machine for setting a reference to a virtual line of the planted seedling row and calculates an error between the reference and the virtual line. Seedling row detection device in the machine.