| JP2000139111 | MARKER CONTROLLING SYSTEM FOR TRANSPLANTER |
| JP04158702 | RIDING RICE TRANSPLANTER |
| JP2001086805 | MARKER CONTROLLING APPARATUS OF TRANSPLANTER |
Kinmont, Andrew Muir (6 Kootangalo Crescent, Ferny Hills, QLD 4055, AU)
Rees, James Ian ("Bristol", Croppa Creek, NSW 2411, AU)
Rees, Steven James (322 Anzac Avenue, Toowoomba, QLD 4350, AU)
Kinmont, Andrew Muir (6 Kootangalo Crescent, Ferny Hills, QLD 4055, AU)
Rees, James Ian ("Bristol", Croppa Creek, NSW 2411, AU)
| 1. | A marking composition whereby to establish a linear array of marks or a line over a surface to be worked by passage of equipment there over, which line is to be followed by a tracking device, characterised in that the marking composition comprises: a base component effective to screen the ground beneath; and a coloured component effective to provide a colour not normally found in the surface being worked. |
| 2. | A marking composition as claimed in Claim 1 wherein the base component is preferably a substantially white pigment, a substantially white foam, or a material which is reflective to incident light such as a paste formed with a product such as rice hulls, or aluminium. |
| 3. | A marking composition as claimed in either one of claims 1 or 2 wherein the coloured component is a blue dye or pigment. |
| 4. | A method by which to effect steering or tracking of equipment such as agricultural apparatus, to control its travel over a surface to be worked by the apparatus characterised in that the method comprises: laying down a linear array of spots or a line over the surface, such as by using a composition as claimed in claim 1; sensing the presence of the array or line relative to the width of the apparatus; and signalling to an operator or steering controller the position of the apparatus relative to the line. |
| 5. | A method as claimed in claim 4 wherein the presence of the line is sensed by splitting the field of view of an imaging device aimed at the ground into segments, counting the number of pixels returned by the imaging device, deemed to have the colour of the marking composition, in the respective segments, and signalling the operator which segment contains sufficient pixels to establish that it contains the line. |
| 6. | A method as claimed in claim 5 wherein the output of the imaging device is examined pixel by pixel with segmentation effected by counting off the pixels across the full line scan of the imaging device and maintaining a coloured pixel count across successive segments of the full line scan of all horizontal scan lines and then counting how many horizontal scan lines in each segment are set until a threshold is reached. |
| 7. | A method of tracking as claimed in claim 6 wherein the successive segments are associated with a respective indicator means with activation of the indicator means which is associated with a respective segment wherein the coloured pixel count for that segment exceeds a threshold. |
| 8. | A control means by which to effect supply of a signal for guidance of an operator of agricultural equipment, or, by which to effect direct control thereof characterised in that the control means comprises: a sensor responsive to a composition of the type claimed in claim 1, laid, in use, on ground being worked by the equipment, directed at ground ahead of the equipment; a processor receiving the output of the sensor and generating a signal representative of the position of the equipment relative to the line; and output means whereby the relative position is indicated to an operator of the equipment, or supplied to a guidance control thereof. |
| 9. | A control means as claimed in claim 8 wherein the sensor is a CCD imaging device outputting a sequence of pixels representing colour levels across the field of view, and the processor determining position examines pixels, counting pixels with the colour component of the composition across segments of a full scan line of the CCD imaging device, and identifying that segment wherein the pixel count exceeds a threshold. |
| 10. | 1 0. |
| 11. | A control means as claimed in claim 9 wherein the output means is a visual indicator with a light emitting device associated with each segment and the processor activates that light emitting device associated with that segment wherein the number of pixels counted exceeded the threshold. |
| 12. | An agricultural equipment incorporating a control means as claimed in any one of claims 8 to 10 wherein the output of the processor is utilised to activate a steering means by which to effect automatic tracking of the equipment along a line laid for the equipment to follow. |
BACKGROUND OF THE INVENTION When ground tillage equipment, and the like, eg planters, cultivators, boomsprayers, etc, is used in either of broadacre and row crop applications, an operator must estimate the degree of overlap of the equipment, in any subsequent pass over an adjoining area, with that area which was covered in the previous pass. The equipment is often drifting or moving away from the edge of the previous pass, either to increase the degree of overlap and uselessly rework the same ground, or away therefrom to leave ground unworked. If the equipment is to be used at maximum efficiency, any divergence either way must be kept to a minimum.
In order to assist the operator in estimating the degree of overlap, and in maintaining a desirable line of travel, many methods have been tried. The most successful is the use of a marker means which cuts a mark in the ground. This defines a line for the operator to follow. FIG. 1 illustrates the problem. A prime mover, typically a tractor, 10 is drawing a cultivator/planter 11, or the like, over ground 12, on a path which runs beside the area 1 3 which was prepared in a prior run. Depending on operator skill, the overlap 14 may be large, non-existent, or negative.
Generally, a marker means is mounted on a folding arm, one marker means on each side of the equipment, each mounted to typically extend out a distance which is equivalent to one half the width of the equipment. Usually a disc is mounted on the end of the
arm to cut a mark in the ground. FIG. 2 illustrates this prior art solution to the problem. An arm 1 5 carries a marker at its end by which the ground is scored at 1 6 to provide a guidance line on the next run. The line 17 which is being tracked is the line which was created on the previous run. The operator need only keep the tractor directly over this line.
The problem with the above described marker means is that it is highly mechanical and the marker arm is subject to considerable stress in use. Such markers have a relatively short life.
Also the added width effected by the marker creates a problem near trees, fences, creeks and contour banks.
Another approach, specifically for boomsprayers, has been to spray a foam marker at the end of the boom to give a visual indicator to the operator. The foam can be blown about in wind. It can dissipate quickly. The operator can be seated some 10 to 70 metres from the end of the boom making it hard to judge overlap correctly. At these distances a side mounting on an extension arm is not practical to put the line in a position which is convenient to the operator. An extension would be subject to some of the deficiencies stated above.
OBJECT OF THE INVENTION It is an object of the present invention to provide compositions, apparatus, and methods by which to establish an improved marker or indicator line, which is able to be readily established and efficiently tracked, so as to enable an operator of agricultural and like type equipment to follow that line, effecting the operation without the need of mechanical ground engaging devices, and effective to enable signalling of position by use of a remote sensor. Other objects and various advantages of the invention will hereinafter become apparent.
NATURE OF THE INVENTION
The invention achieves its object in firstly the provision of a marking composition whereby to establish a marked line over a surface or ground, which line is to be followed by a machine or the like by use of a method of tracking adapted to respond to the composition, which marking composition comprises: a reflective component; and a coloured component.
The invention preferably utilises, as a base component, materials which are compatible with general agricultural processes, by being a generally harmless addition to the agricultural environment. Foam marking compositions are supplied by a number of companies to the rural industry and any of these proprietary compositions might be employed as a base component. The base component may be a hydrated lime or titanium dioxide, as used in the marking of tennis courts. A gelling agent such as Laponite RD can be added to resist the settling out which might occur with the aforesaid components. A product such as rice hulls is expected to provide a useful reflective component to create a paste with useful qualities as a base to a marking composition. The purpose of the base is to provide a ground for the colour component, otherwise the ground colours can invade the marker colour and upset the output of a CCD camera. A blue dye is preferred as it is not often detected in those field circumstances where tracking has been attempted.
The invention secondly provides a method of tracking by which the travel of an agricultural machine, or the like, can be controlled comprising: laying down a line over ground to be worked by the agricultural machine, using a marking composition as herein defined; sensing the position of the line relative to the width of the machine; and signalling to an operator the position of the machine
relative to the line or correcting the travel of the agricultural machine to bring it to a desired position relative to the line.
The invention might advantageously be coupled with an automatic steering system to track a line, according to the output of a means which implements the method of the invention.
The invention thirdly provides a means providing an indication of position for guidance of an operator of agricultural machinery or the control of the agricultural machine comprising: a sensor for detecting the presence of a line marked using a composition as herein defined, laid on the ground being worked by the machine; a means for determining the relative position of the machine relative to the line which utilises the output of the sensor; and output means whereby the relative position is made known to the operator or effects control of travel of the agricultural machine.
BRIEF DESCRIPTION OF THE INVENTION The invention will now be described with reference to an embodiment thereof which is illustrated in the accompanying drawings, in which: FIGS. 1 and 2 illustrate schematically the operation of prior art equipment; FIG. 3 illustrates schematically the manner in which the present invention realises the invention's object; FIG. 4 illustrates schematically what blocks of electronics or functions might be utilised in providing an operator of the equipment of FIG. 3 with an indication of position relative to a line; and FIGS. 5 to 8 illustrate in flow diagram form how the functions of FIG. 4 might be implemented.
PREFERRED EMBODIMENT In the present invention a CCD (or its equivalent) imaging system, can be used to locate, indicate or detect the position or presence of a pre-applied mark, sequence of marks or line, created or established in or over a surface or ground which is being worked, and to either drive the machine or vehicle, or establish or provide to an indicator or display, a signal or the like by which to let an operator know where the mark is in relation to the edge of the equipment. The mark(s) or line is ideally sufficiently distinctive from the ground, as by use of a base component, which is effective to screen the ground in a distinctive manner, or achieves the result by being reflective, to enable the imaging system to react to it or identify it easily. Ideally a colour component is employed which, relative to the ground, is easily distinguished from the background.
A blue pigment or die is determined to be most useful in realisation of the invention. Any common blue pigment or die, which is compatible with an agricultural environment (one not being a pollutant or otherwise undesirable) is best used.
A foam marking system involves a container to hold a mix of water and a foaming agent. A generator is used to turn the liquid into foam. Blobs of foam are deposited on the ground. Foam markers are employed with boom sprays. Boom sprays are not constructed to support ground working implements. Operators of the prior art foam markers have added colouring agents to make them easier to see and follow. The present invention operates with a colouring agent which is distinct relative to usual ground colours and blue has been settled on as the most useful colour. A composition made with a proprietary foaming agent will be typically 2% foaming agent, with 1% to 2% of dye in water.
A lime or titanium oxide marker can be typically produced with the lime or oxide added to water in a ratio at between
5 to 1, and 20 to 1. A gelling agent such as Laponite RD is added, typically at half of 1% and a dye at 2% to 5%. The composition can be delivered using standard herbicide or pesticide boom spray nozzles. A solenoid may be associated with the nozzle to switch it and create an intermittent line to save on composition.
After analysing the colour of typical ground types met in agricultural activity, and common ground covers in typical fallow situations, it has been established that blue is a colour which is not often found. After analysing materials that can be sprayed onto ground to produce a line, and which are also sufficiently distinctive to be easily identified, it was found that a white pigment such as lime based materials as used in marking tennis courts, a white foam as is known in the guidance of agricultural equipment, or a reflective material has advantages. A diluted aluminium paste does the required job. Aluminium can be an undesirable addition to agricultural land and although little would be applied, substitutes which are more benign or degradable are desirable. A product such as rice hulls is expected to provide a paste with good qualities as a marker. By adding a blue dye to a white base or reflective paste and diluting it, there is produced a blue composition by which to establish mark(s) or a line, which can be sprayed onto the ground, past the end of the equipment, which mark(s) or line can be readily picked up by an imaging system (as herein described), mounted on the equipment, typically at an end of the equipment such that it is detected on the next pass. Alternately it might be provided behind an end tyne or disc of ground working equipment.
The invention ideally mounts a CCD imaging device, preferably at the end of the implement, and pointing down, so that it has a defined field of view. The CCD will typically reproduce the field of view in an output signal constituted by a sequence or array of pixels (the number will depend on the size of the CCD), each pixel
will be made up of Red, Green and Blue components. The pixels will typically be a series of values across the field of view, constituted line by line.
In FIG. 3 is seen a tractor 10 drawing a cultivator 11, which cultivator may have a spray head 1 8 at its outer edge (another can be mounted on the other end to be used when working to the other side of the machine) which may be adapted to spray or spot a mark onto the ground to create a linear array of dots or a continuous line 1 9. The line 20 is the mark laid down on the previous run. Line 20 can be tracked by a sensor (not shown), ideally mounted at the front edge, preferably effective to cover or see a field of view indicated by the rectangle 22. If the apparatus is to be used the other way round then a similar sensor can be provided at the other end with the field of view indicated at 21.
Evaluation of various plant and background conditions (soil, rock, stubble, etc) has shown that a blue streak can have a blue content that is distinctly higher than the Red and Green content.
The same also holds true for the colour difference signals of R-Y, B- Y, and G-Y. Note that Y is a reference to luminance. It should be noted that there are practical advantages in working with the colour difference signals instead of the red, green and blue signals. T h e first advantage is that by using the colour difference signals, the effects of ambient light level can be largely ignored. A second advantage is that broad level CCD cameras with colour difference outputs are more readily available than those with straight red, green and blue outputs.
In utilising the CCD output, the output is ideally processed or operated on to divide or split the horizontal field of view of the CCD into equal parts to create, for example, 10 segments or regions (this will give the indicator an accuracy of 1/10 the field of view). Then, in performance of the invention, the
process is to preferably count the number of pixels in each region.
When the number of blue pixels in a region exceeds a preset threshold, the indicator pertaining to that region might be activated.
The preset threshold is ideally set at a level which is big enough so that false triggers from dark areas, or noise, will not exceed the number set, but, when the blue streak is in the region, it will activate the system.
To determine if any pixel is blue or not blue, a simple analog comparison can be made, between the instantaneous (R-Y) and (B-Y) signals for the pixel, and also the instantaneous (G-Y) and (B-Y) signals for the same pixel. If, in both cases, the (B-Y) signals is greater, the pixel might be considered to be blue. Once the horizontal field of view is divided into its regions, the total number of blue pixels in each region may be counted using a hardware counter, implemented with logic components. The comparison between the blue pixel count and a threshold can be implemented in hardware with logic components. At the end of each horizontal scan of the CCD, the results of these comparisons between the number of blue pixels in each region and a set threshold, may be stored in memory until a complete frame of data has been assembled. At this time, software in the microprocessor system might then check for adjacent horizontal scans in a region which are blue. If the number of adjacent horizontal scans is greater than a preset threshold, then the indicator for that region might be activated. This checking of adjacent horizontal scans can help filter any erroneous results, and it can be most important when the system is endeavouring to discern very small sprayed lines, although it is possible to just use the total number of horizontal lines. Clearly there are a number of processes by which counting may proceed and one is set out in FIG. 5 below.
To prevent more than one indicator coming on at one time when the frame is finished, the processor can check what number of indicator
flags are set, and if it exceeds one (1), then the previous indicator remains lit. It may be useful to use an algorithm which works with R-Y and G-Y below a threshold and B-Y above a set threshold.
These thresholds may be set at a level which stops false triggers and still triggers at the presence of the mark.
A practical consideration under low light conditions, and with commercially available broad level CCD cameras, is that there is a component of noise present on the cameras output signals. It has been found that under these circumstances, it can be better to compare the (B-Y) signal to a fixed reference voltage slightly offset from the signal level for black. This can produce much better noise immunity, while still providing a valid implementation of the algorithm, since for a Blue pixel, the (R-Y) and (G-Y) signals are generally below the black signal level. A light might be used to light the field of view for night time use.
FIG. 4 is the diagram of a circuit which may be used in a controller in accordance with the present invention. The output of the CCD imager is a sequence of RGB signals for pixels in the field of view. Red (R) is output on line 24. Blue (B) on line 25. And Green (G) is on line 26. Comparator 27 compares B with R. Comparator 28 compares B with G. The comparator outputs are monitored by the AND circuit 29 and if both of B>R and B>G applies then a blue pixel counter 31 may be activated with a one bit digitizer 30 interface. As the CCD output is a series of pixels across the field of view, the blue pixel counter can count across segments of the scan line, recording the respective total for each segment as the scan proceeds. The blue pixel count for each segment can be compared with a threshold set in operator settable variable threshold 32 and if exceeded the region can be determined to be blue and over the line.
A bank of indicators 34, one for each segment, is subject to indicator check 33 which switches off previously activated indicators
and fires the indicator newly appropriate.
FIGS. 5 to 8 show in flow chart form the sequence of operations by which an indicator activation signal might be generated. This is illustrated with reference to the B>R and B>G version and area calculation based on a scan line approach.
FIG. 5 shows a particular form of the main process operating with four regions. Normally 10 or more are used but 4 will save on repetition in description. On start up at 150, the scan line process 151 (described below in greater detail with reference to FIG.
6) is implemented. The first region of a scan line is examined at 1 52 and if it is deemed to be blue, and the previous scan line was blue in this region, see 153, then a counter is incremented at 154, otherwise it is cleared at 157, and the second region is processed at 1 58 in the same manner. If the scan line counter for region 1 is incremented at 154, then the count is compared at 1 55 with a threshold and, if it exceeds it, then an indicator or flag is set at 156, otherwise processing passes to region two at 1 58. The foregoing processing is pursued through the third (159) and fourth (160) regions until the full frame is determined to be completed at 161 at which point the indicator control process 1 63 is carried out.
The scan line process at 151 of FIG. 5 is seen in greater detail in FIG. 6. On starting the scan line process at 164, the region process 1 56 (described below in greater detail with reference to FIG.
7) is implemented. If the last region on a scan line is determined to be processed at 166, then the scan line process exits to the "is it blue" decision process at 152 of FIG. 5, otherwise the scan line process loops. The region process at 165 is seen in FIG. 7 wherein on its commencement at 1 68 the detector output is examined pixel by pixel. On receipt of a pixel at 169 the algorithm B>R and B>G is implemented at 1 70. If both conditions apply, then a blue pixel counter is incremented at 171. The end of region is tested at 172
with processing looped to continue if the end of region is not reached. When it is at the end of the region the process continues with the blue pixel count compared to a threshold at 1 73. If the threshold is exceeded, then a blue region flag is set at 1 74 and processing passes back to the scan line process.
When the full frame has been processed, it passes to the indicator control process FIG. 8. On start up it counts the number of indicator flags set at 1 78 and if it exceeds 1 at 1 79 it leaves the previous indicator on at 1 86 with then the clearing of indicator flags at 1 87 to finally exit to the main process. If the number of indicator on flags set 1 78 does not exceed 1, the process goes through a check of all regions 1 80 - 1 83 to find the region that is set. The process then clears the previous indicator at 1 84. Then the process turns on the current region indicator at 1 85 and it clears the indicator flags at 1 87 and exits to main process for a repetition of the total process.
The output from the above process can be used to light up an indicator in a bank of indicators to reveal the degree of overlap. Obviously a variety of indicators exist by which to signal the level or degree of deviation from the ideal. The output from the process may alternately be used to control the steering of the apparatus so as to automatically effect any required correction.
Automatic steering mechanisms are known as in cotton harvesters with the output of their sensors utilised to effect steering via hydraulic means. These systems will be routinely implemented with the present process substituted as the sensor mechanism.