JPH07114495B2 - Grain culm identification method in harvester - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for identifying a grain culm using an image sensor provided in a harvester.

[Prior art]

Photodiodes, CCD (C harge C oupled D evice, charge-coupled device) image sensor made using such has excellent properties that the size of the detected object, the position and many other information can be detected in a non-contact In addition, due to the progress of semiconductor technology, high performance products have become available at a relatively low cost, and they have started to be widely used as control sensors in various industrial fields.

[Problems to be solved by the invention]

In the harvester, an image sensor is provided to image the grain culm in the transport route from the mowing unit to the threshing unit, the culm length of the grain culm is detected to control the handling depth, and the forward direction of the harvester. An image sensor is provided in order to image the grain culm row planted in the plant, and steering control is performed by detecting the relative position of the airframe with respect to the grain culm row, and application examples of the image sensor as various control sensors are considered. To be

By the way, the harvester is mainly operated outdoors due to its use, and in many cases it is also operated day and night in the agricultural season, so the image sensor used as the control sensor is used during the daytime. Under natural light,
In addition, at night, the object to be imaged is imaged under illumination.

However, when the image sensor is used as the steering control sensor of the harvester as described above, the grain culm, which is the imaging target of the sensor, is imaged dark against the background under natural light and is not illuminated. In contrast, since the image is picked up brightly against the background, if the processing method of the image signal from the image sensor is the same regardless of day or night, there is a possibility that the relative position of the aircraft with respect to the grain culm may be erroneously detected at night. ,
Furthermore, for example, at dusk or during rainfall, the amount of natural light is insufficient, making it difficult to distinguish between the grain culm row and the background from the image pickup result of the image sensor under natural light, and the relative position of the aircraft is erroneously detected. May be

As described above, in any case, there is a problem that steering control cannot be performed correctly based on the detection result of the image sensor.

The present invention has been made in view of such circumstances, and when an image sensor is used as a grain culm identification sensor of a harvester, it is possible to provide a method capable of accurately identifying grain culm day and night. To aim.

[Means for solving problems]

The grain culm identification method in the harvester according to the present invention uses the image sensor mounted on the harvester to binarize an image signal of an image obtained by capturing an area including a working area and a non-working area in front of the traveling direction of the harvester. In the method of processing and identifying a grain culm based on image data after binarization, an average value of brightness of image data of an imaging field of view obtained by the image sensor is obtained, and this average value is compared with a reference value. However, when the value is lower than the reference value, the illumination provided in the harvester is turned on, and after the illumination is turned on, the binarized image data is inverted.

〔Example〕

The present invention will be described below with reference to the drawings showing an embodiment thereof. In this example, a grain culm identification method (hereinafter referred to as the method of the present invention) in a harvester according to the present invention will be described.

FIG. 1 is an external perspective view of a harvester equipped with a grain culm identification sensor using an image sensor, FIG. 2 is a schematic view of a harvesting work together with a schematic plan view of the harvester, and FIG. 3 is steering control. It is a block diagram of a system.

In the figure, 1 is a traveling crawler, on the upper side of which a threshing section 2, a driver's seat DS, etc. are mounted, and a main body section 3 is constituted by these, and on the front side of the main body section 3, a weed board 4, a grain culm A mowing unit 6 including a raising device 5 and the like is attached so as to be able to move up and down.

The traveling crawlers 1 are provided on the left and right sides of the main body 3, respectively, and are driven by the engine of the harvester via respective clutches (not shown).

These clutches are clutch cylinders 10l, shown in FIG.
It is designed to be engaged and disengaged separately by 10r. When the clutch cylinder 10l operates, the clutch of the right running crawler 1 is disengaged and the aircraft turns left. When the clutch cylinder 10r operates, the left steering The clutch of the crawler 1 is disengaged and the aircraft steers to the right.

The hydraulic circuit for supplying pressure oil to the clutch cylinders 10l, 10r is composed of a hydraulic pump P, an electromagnetic directional control valve V, an oil tank T and the like. The electromagnetic directional control valve V is a 4-port, 3-position switchable type, and when its solenoid Sl (or solenoid Sr) is excited, the electromagnetic pump from the hydraulic pump P enters the oil chamber of the clutch cylinder 10l (or clutch cylinder 10r). The pressure oil is fed, the piston rod advances, the oil chamber of the clutch cylinder 10r (or clutch cylinder 10l) communicates with the oil tank T, and the piston rod retreats to the left side (or the right side) as described above. ) The traveling crawler 1 is stopped, and the aircraft is left-handed (or right-handed). If both solenoids Sl and Sr are demagnetized, the clutch cylinder 10l,
Both the oil chambers of 10r communicate with the oil tank T, these piston rods both retract, the left and right traveling crawlers 1 are driven at a constant speed, and the machine body moves straight.

Now, the grain culm identification sensor 7 using the image sensor,
An imaging field of view A as shown by a chain double-dashed line in FIG. 2 including a row of uncut grain culms planted on the field surface in front of the harvester as a part thereof.
In order to capture an image of the inside, it is attached at a position near the driver's seat DS on the upper part of the reaping unit 6 and slightly toward the lower front. Reference numeral 70 denotes a light projector for irradiating the entire imaging visual field A with light, which is provided in parallel with the grain culm identification sensor 7 on the upper part of the cutting unit 6.

The grain culm identification sensor 7 has, for example, a CC having a number of pixels of n × m.
D 71, an optical lens 72 for forming an image of an object on the photosensitive surface of the CCD 71, and the output is A /
It is provided to the image signal processing unit 8 including the D converter 81, the video memory 82, and the operation control unit 83. Each pixel of the CCD 71 accumulates electric charges according to the intensity of the light irradiated on its surface and the irradiation time, and each time a clock pulse is given at a predetermined time interval from the arithmetic control unit 83, each pixel is stored. The image signal of the level corresponding to the electric charge accumulated in the pixel is output to the A / D converter 81 of the image signal processing unit 8 in the order in which the traveling direction of the machine body is the main scanning direction and the direction orthogonal thereto is the sub scanning direction. To do. And the image signal from CCD 71 is A / D converter 81,
According to the level, for example, analog / digital conversion is performed in 16 steps, and "0000" representing the darkest part in the video memory 82.
Is stored as 4-bit image data from "1111" to the brightest part.

The operation control unit 83 using a microcomputer reads out the image data stored in the video memory 82, performs the operation described later from this data, and controls the level according to the relative position of the machine to the row of grain stems. Signal control unit 9
And outputs a signal to the light projector 70 to turn it on or off according to the brightness of the imaging field A of the grain culm identification sensor 7.

The solenoids Sl, Sr of the electromagnetic directional control valve V are connected to the output side of the steering control unit 9 via an exciting circuit (not shown), and the steering control unit 9 receives the input from the arithmetic control unit 83. If the signal level is above a specified value, the solenoid Sl
To turn the corresponding output port to a high level to turn the aircraft to the left, and to excite the solenoid Sr when the level of the input signal is equal to or less than another predetermined value that is less than the predetermined value. The corresponding output port is set to high level and the aircraft is steered to the right to control the steering of the harvester.

FIG. 4 is a flowchart showing the control contents of the arithmetic control unit 83, and the method of the present invention will be described below with reference to this drawing.

The harvester runs on the field while operating the mowing unit 6,
At the mowing unit 6, grain culms to be planted on the field are mowed. During this time, the grain culm identification sensor 7 images the rows of grain culms in the imaging visual field A from above together with the field surface as a background, as described above.
FIG. 5 and FIG. 6 are schematic diagrams showing the imaging results of the grain culm identification sensor 7, respectively, and FIG. 5 is an image when the harvester is traveling while maintaining a regular position with respect to the grain culm row. The results are shown in FIG. 6, which shows the imaging results when the vehicle is traveling to the left, that is, the grain row side, as compared with the normal position.

The arithmetic control unit 83 resets the register that stores the index L indicating whether or not the projector 70 is turned on. The register stores 1 when the projector 70 is turned on and 0 when the projector 70 is turned off. Next, the arithmetic control unit 83 resets the register for storing the total S of the image data D _ij corresponding to each pixel of the CCD 71,
The image data D _ij stored in the video memory 82 are sequentially read, these are added to calculate the value of S, while these are binarized based on a predetermined threshold value D ₁ to create a bright portion. Two image data ▲ D ^' _i ▼ _j consisting of "1" represented and "0" represented in the dark area are sequentially written in the memory in the arithmetic control unit 83.

In this way, after the total S of the n × m image data D _ij stored in the video memory 82 is obtained, this is divided by n × m to obtain the average brightness Da in the imaging visual field A. calculate.
This value Da naturally has a large value when the imaging visual field A is bright, and has a small value when it is dark. Therefore, the average value
Da is compared with preset brightness reference values D ₂ and D _{3, respectively,} and when Da is D ₂ or less, the corresponding output port is turned to the high level to turn on the projector 70, and the index The binary image data ▲ D ^' _i ▼ obtained previously with L set to 1.
Video memory without steering control based on _j
Read the next image data from 82.

On the other hand, when Da is equal to or greater than D ₃ , the corresponding output port is turned to low level to turn off the projector 70, the index L is set to 0, and Da is a value between D ₂ and D _3. In this case, without changing the output to the projector 70, the process proceeds to the next stage in order to carry out the steering control based on the previously obtained binary image data ▲ D ^' _i ▼ _j .

By the way, the part of the grain culm row shown by hatching in FIGS. 5 and 6 is imaged darker than the background under natural light due to diffuse reflection of light, and image data after binarization ▲ D
^′ _I ▼ _j is “0” in the portion existing in the grain culm row and “1” in the background portion. However, when the amount of natural light is insufficient, such as during twilight or during rainfall, the difference in brightness between the background and the grain culm decreases, and the binary image data ▲ D ^′ _i ▼
_It is difficult to judge these at _j . The reference value D ₂ is set to a value slightly larger than the limit brightness that makes it difficult to distinguish the background from the grain culm, and as described above, the average value Da of the brightness in the imaging visual field A is D ₂ In the following cases, the projector 70 that illuminates the imaging visual field A is turned on to compensate for the insufficient light amount in the imaging visual field A, and the background and the grain line can be easily distinguished. Further, the reference value D ₃ is, when the average value Da of brightness becomes equal to D ₂ ,
The value is set to a value slightly larger than the brightness in the imaging field of view A obtained by turning on the projector 70, and even if the projector 70 is turned off when the average brightness value Da becomes D ₃ or more as described above. The brightness in the imaging visual field A is maintained at the reference value D ₂ or more by natural light, and there is no hindrance to the discrimination between the grain culm row and the background.

In this way, the light projector 70 is turned on and off according to the brightness of the image picked up by the grain culm identification sensor 7,
The brightness in the imaging visual field A is always kept at a proper brightness regardless of day and night, and binary image data ▲ D ^′ _i ▼ described below is used.
_It is possible to easily distinguish the grain culm row from the background by _j .

As described above, under natural light, the part of the grain culm is imaged darker than the background, but under illumination by the projector 70, the distance from the projector 70 to the upper surface of the grain culm and the background from the projector 70. Due to the difference with the distance to the field surface, contrary to the imaging result under natural light, the part of the grain culm shown by hatching in FIGS. 5 and 6 is imaged brighter than the background, Image data after binarization ▲ D ^' _i ▼
_j is "1" in the grain culm row portion and "0" in the background portion, and is written in the memory in the arithmetic control unit 83. The arithmetic control unit 83 compares Da with D ₂ and D _3, and after performing the above-described processing, determines whether L is 1 or 0, that is, the projector.
It is checked whether 70 is lit, and if L is 1, subtract binary image data ▲ D ^′ _i ▼ _j from “1”,
The result is written in its own memory, and when L is 0, the image data ▲ D ^' _i ▼ _j is left as it is and the process proceeds to the next stage. By doing this, the binary image data "1" when L is 1 is inverted to "0", and "0" is inverted to "1".
The binary image data ▲ D ^′ _i ▼ _j obtained from the imaged result under illumination when the light projector 70 is turned on also has a grain culm row portion of “0”, as in the imaged result under natural light. The portion becomes "1", and the image pickup result of the grain culm identification sensor 7 under natural light and the image pickup result under illumination can be processed by the same method as described below. Then arithmetic control unit
The 83 sequentially reads the binary image data ▲ D ^′ _i ▼ _j from its own memory, counts the number of data “1” in this image data, and determines the area of the bright portion in the imaging visual field A, that is, the background area. After obtaining the area B of the portion and outputting a control signal of a level corresponding to this size to the steering control unit 9, the next image data D _ij is read from the video memory 82 and the same processing is repeated.

By the way, since the grain culm identification sensor 7 is fixed to the upper part of the mowing unit 6, it moves according to the movement of the harvester to the left and right, and when the harvester approaches the grain culm row side to be mowed from the regular traveling position. As shown in FIG. 6, the area B of the background portion in the imaging visual field A becomes small (when approaching the non-working area side), and as a result, the calculation control unit 83 outputs it to the steering control unit 9. Since the level of the control signal becomes small, the steering control section 9 operates so as to excite the solenoid Sr of the electromagnetic directional control valve V as described above, and the harvester is steered to the right so as to be separated from the grain culm row. It

On the other hand, when the harvester moves away from the grain culm row (when it moves from the unworked area side to the already worked area side), it is not shown in the drawing, but in the imaging field of view A contrary to the case of FIG. The area B of the portion other than the grain culm row becomes large, and as a result, the calculation control unit 83
Since the level of the control signal from V becomes large, the steering control unit 9 operates to excite the solenoid Sl of the electromagnetic directional control valve V, and the harvester is steered to the left so as to approach the grain row.

As described above, the area B of the background portion has a value corresponding to the relative position of the harvester with respect to the grain culm row, and the steering control unit 9 operates based on the control signal of the level corresponding to this value. The harvesting machine travels on the field while being steered and controlled so as to always maintain a constant relative position with respect to the rows of grain stalks planted on the field.

〔effect〕

As described above in detail, in the method of the present invention, when the image sensor is used as the grain culm identifying means in the harvester, the brightness of the image of the image sensor is insufficient, and it is difficult to distinguish between the bright part and the dark part. In this case, since the lighting is turned on, it is possible to accurately detect the grain culm by the image sensor regardless of day and night, and when the lighting is turned on,
After binarizing the image signal from the image sensor, the binarized image data is inverted, so that the image signal obtained from the imaging result under natural light in the daytime and the imaging result under illumination at night are the same. It is possible to accurately identify the grain culm by processing by the method, and there is an excellent effect that the harvesting work can be performed day and night.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is an external perspective view of a harvester equipped with an image sensor as a grain culm identification sensor, a second is a schematic view of a cutting operation, and FIG. FIG. 4 is a block diagram of the control system, FIG. 4 is a flow chart showing the control contents of the arithmetic control unit, and FIGS. 5 and 6 are schematic diagrams showing the imaging results of the grain culm identification sensor. 1 ... Traveling crawler, 6 ... Mowing section, 7 ... Grain identification sensor, 8 ... Image signal processing section, 9 ... Steering control section 10l, 10
r ... Clutch cylinder, 70 ... Emitter, 83 ... Arithmetic control unit, A ... Imaging field of view

Claims (1)

[Claims] 1. A binarized image signal of an image obtained by picking up an area including an already-worked area and an unworked area in front of the traveling direction of the harvester by an image sensor mounted on the harvester, and binarized the image signal. In a method for identifying a grain culm based on image data, the average value of the brightness of the image data of the imaging field of view obtained by the image sensor is obtained, and the average value is compared with a reference value, and when it is lower than the reference value. A method for identifying a grain culm in a harvesting machine, comprising: turning on an illumination provided on the harvester, and inverting the binarized image data after the illumination is turned on.