Patent Publication Number: US-2023136009-A1

Title: Method, vehicle and system for weed control management

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method for weed control management, to vehicle(s) for weed control management, to a system for weed control management, as well as to a computer program product. 
     BACKGROUND OF THE INVENTION 
     The general background of this invention is weed control and in particular pre-emergence weed control. Modern agriculture faces many challenges in producing sufficient food in a safe and sustainable way. One of the challenges that affect the quality and quantity of agricultural produce comes from unwanted weeds, which can have significant negative impacts on the yield and quality of agricultural produce. Solutions to this include spraying agricultural fields with chemical and biological herbicidal products, both prior to the emergence of weeds and after their emergence. However, these approaches have the disadvantage that relatively high amounts of products are applied and not always at the optimum time or place. A highly efficient treatment is at the pre-emergence stage but after germination when the first roots are developing. Herbicidal products that inhibit the growth of roots are very effective at this stage where the roots are not sufficiently developed to overcome the inhibition effect of the herbicidal products. However, as the location of the weeds is not known at the pre-emergence stage herbicidal products are applied on the whole field and not only where weeds are growing. 
     SUMMARY OF THE INVENTION 
     It would be advantageous to have improved means for weed control management (and in particular for pre-emergence weed control management) in order to apply chemical and biological herbicidal products more specifically to agricultural fields. The object of the present invention is solved with the subject matter of the independent claims, wherein further embodiments are incorporated in the dependent claims. It should be noted that the following described aspects and examples of the invention apply also for the method for weed control, the vehicle(s) for weed control, the system for weed control, and for the computer program product. 
     According to a first aspect, there is provided a method to control weeds comprising the steps of: 
     a) acquiring geopositional information of planted crop seeds on an agricultural field and generating a crop seed map,
 
b) acquiring soil elevation data and the corresponding geopositional information of the soil elevation on the agricultural field where the crop seeds have been planted or are being planted at at least two different time points and generating soil surface profile maps of the agricultural field, the soil surface profile maps showing the soil surface profiles at the at least two different time points,
 
c) comparing the soil surface profile maps and the seed map to identify differences in the soil elevation profile that are not associated with seed growth of the planted seeds on the agricultural field,
 
d) generating a weed control agent spray map on the basis of the differences in the identified soil elevations on the agricultural field that are not associated with seed growth of the planted crop seeds on the agricultural field.
 
     Thus, the geolocation of the crop seeds in the soil on the agricultural field is recorded during planting. The crop seed map refers to a two-dimensional or three-dimensional display of the crop seed geopositional distribution on an agricultural field after planting. The soil elevation profile of the agricultural field is measured e.g. shortly after planting of the crop seeds and later—at a second time point—when weeds have begun to germinate but not yet emerged or just emerged. By data comparison, the differences in the soil elevation profiles at two different time points indicate where weeds potentially grow. Before weeds emerge, the soil is displaced as the growing shoot pushes upwards. This soil displacement can be detected by appropriate sensors. Machine learning algorithms support the discrimination of soil displacements due to reasons not associated with the weed germination such as for example soil displacements due to weather incidents, soil erosions, bird and animal marks etc. As it is decisive that the emerging crop seeds are not sprayed and as the soil displacement caused by weeds and crops can be similar it is necessary to identify the geolocation of the crop seeds during planting and to consider the geolocation of the crop seeds when generating a weed control agent spray map. The weed control agent spray map refers to (at least a) two-dimensional (or three-dimensional) display of weed (germination and emergence) geopositional distribution on an agricultural field where a weed control agent can be applied to appropriately control the weeds on the field. In this manner, weeds can be identified at a very early point in time which allows precision farming weed control applications at the pre-emergence phase. 
     In an example, the data for the crop seed map and the soil surface profile map showing the soil surface profile at the first time point are acquired on the agricultural field with an agricultural vehicle at the same time. 
     In other words, the data for the crop seed map and the soil surface profile data for a first time point are acquired in one operational process. E.g. a seed planter vehicle is planting crop seeds on an agricultural field. The geolocation of the crop seed is recorded during the planting process. E.g. with a seed metering system with a sensor that senses a passing seed, a timer to timestamp when a seed passes the sensor; all synchronized with a GPS system of the seed planter vehicle. At the same time a sensor on the seed planter vehicle can acquire data in regard to the soil elevation profile at a first point in time. These combined operational processes have the advantage that no additional ground vehicle operation is necessary for acquiring the necessary data on the agricultural field with benefits in regard to CO 2  emissions and avoidance of soil compaction damage. 
     In an example, the method comprises and additional step e), wherein a weed control agent is applied to the agricultural field according to the weed control agent spray map. 
     In other words, the weed control agent spray map can be used by a vehicle to apply a herbicide in a precision farming approach at a very early weed growth stage. This has the advantage that not only less herbicide is sprayed due to the precision application approach but that also less herbicide is necessary because the weeds at an earlier growth stage are easier to control than at a later stage. 
     In an example, the steps a) to e) of the method are performed prior to the emergence and/or during the emergence of a plurality of shoots of the crop seeds and/or weeds on the agricultural field. 
     Thus, the method of weed control management is in particular useful at an early growth stage after crop seeds have been planted when competition for nutritional resources between the crop seed plants and weeds is high. 
     In an example, the geopositional information of the planted crop seeds on the agricultural field is acquired by at least one sensor that is configured to record geopositional information of the crop seeds impinging on the soil during planting of the crop seeds. 
     Thus, various known detection techniques can be used to acquire information about the geolocation of the seeds on the agricultural fields. As described above, a metering system with a sensor that senses a passing seed, a timer to timestamp when a seed passes the sensor, in synchronization with GPS system can be used to assess the geoposition of crop seeds on the agricultural field. Alternative techniques include for example image analysis of images acquired with a camera from seeds impinging on the soil during the planting process together with GPS data. 
     In an example, the soil elevation data and the corresponding geopositional information of the soil elevation on the agricultural field is acquired with a sensor that is configured to generate pulses of light towards the soil surface and to measure the time for any reflections and location determining means. 
     In this manner, known sensors such as a lidar sensor (also known as LIDAR and LiDAR) with high resolution in combination with a GPS system can be used to acquire the soil elevation data. 
     According to a second aspect of the invention, there is provided a vehicle for weed control management comprising a plurality of sensors comprising at least one seed position sensor and at least one soil elevation sensor, a control and processing unit, and a seed planting unit. The vehicle is configured to plant crop seeds on an agricultural field with the seed planting unit. The at least one seed position sensor is configured to collect seed geoposition data of the crop seeds impinging on the soil surface from the seed planting unit during planting. The control and processing unit is configured to receive the seed geoposition data from the at least one seed position sensor to generate a crop seed map of the agricultural field. The at least one soil elevation sensor of the vehicle is configured to collect soil elevation data, the soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field. The control and processing unit is configured to receive the soil elevation data from the at least one soil elevation sensor to generate a soil surface profile map of the agricultural field, wherein the soil surface profile map shows the soil surface profile at a first time point. The seed position data and the soil elevation data are acquired at the same instance when the plant crop seeds are planted on an agricultural field with the seed planting unit of the vehicle. 
     In other words, the vehicle for weed control management can be a seed planter vehicle with appropriate sensor equipment to measure the geolocation of the crop seeds on the soil as well as the surface structure (with high resolution) of the agricultural field shortly after the planting process (e.g. after the wheels of the seed planter vehicle have passed). In this manner, useful data for weed control management can be obtained during the planting process. 
     In an example, the vehicle for weed control management comprises an output unit. The output unit is configured to receive the crop seed map of the agricultural field and the soil surface profile map of the agricultural field from the control and processing unit. The output unit is configured to output the crop seed map of the agricultural field and the soil surface profile map of the agricultural field. 
     In other words, the crop seed map and the soil surface profile map can e.g. be shown to a farmer on a monitor, hand held, printer, screen or any other information monitoring device/medium. 
     According to a third aspect of the invention, there is provided a (second) vehicle for weed control management comprising at least one soil elevation sensor, a control and processing unit, and a transceiver. The at least one soil elevation sensor is configured to collect soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field at a first time point. The at least one soil elevation sensor is configured to collect soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field at a second time point which is after the first time point. The control and processing unit is configured to receive the soil elevation data from the at least one soil elevation sensor and to generate soil surface profile maps of the agricultural field at at least two different time points. The control and processing unit is configured to utilize the transceiver to receive a crop seed map of the agricultural field. The control and processing unit is configured to compare the soil surface profile maps and the crop seed map to identify differences in the soil elevation profile that are not associated with seed growth of the planted seeds on the agricultural field and to generate a weed control agent spray map. 
     To phrase it differently, a vehicle acquires soil elevation data at a first and a second time point (which can be e.g. a view days/weeks later than the first time point). The vehicle also receives information about the crop seed map as generated at an earlier point in time. The control and processing unit of the vehicle uses generated and received information to generate a weed control agent spray map. The calculation and generation of the crop seed map, the soil surface profile map(s) and/or the weed control agent spray map can also be done on an external processing unit and the information/analysis can be sent to the vehicle that requires the information/analysis. 
     In an example, the control and processing unit of the (second) vehicle is configured to utilize the transceiver to receive the soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field at the first time point and/or the soil surface profile map of the agricultural field for the first time point. 
     In this manner, the second vehicle does only need to acquire soil elevation data at a second point in time and can use the soil elevation data as generated by a first vehicle (e.g. by a seed planter vehicle during the planting process) or other vehicles. The second vehicle for example receives the data via wireless communication and uses this information to generate a weed control agent spray map. Thus, it is possible that the second vehicle does generate the weed control agent spray map while being on the agricultural field which enables the vehicle to directly initiate weed control measurement while being at the location where weed control measurements are required. 
     In an example, the (second) vehicle for weed control management comprises an output unit. The output unit is configured to receive the weed control agent spray map for the agricultural field from the control and processing unit. The output unit is configured to output the weed control agent spray map for the agricultural field. 
     In an example, the (second) vehicle for weed control management comprises at least one weed control agent spray unit. The at least one weed control agent spray unit is configured to eject a weed control spray agent. The control and processing unit is configured to control the at least one weed control agent spray unit according to the weed control agent spray map. 
     Thus, the second vehicle which acquires the soil elevation data at a second time point has all data to generate the weed control agent spray map. In order to do so the vehicle can also use external processing capacity. However, at the same time when the vehicle is on the agricultural field acquiring soil elevation data for a second time point it can analyse the data and start with controlling the weeds e.g. by spraying an appropriate herbicidal product where required. This continuous process increases efficacy. 
     In a fourth aspect of the invention, there is provided a weed control agent spray map generated according to the method as discussed under the first aspect of the invention. 
     In a fifth aspect of the invention, there is provided a system for weed control management comprising a first vehicle for weed control management and a second vehicle for weed control management. The first vehicle comprises at least one seed position sensor, a control and processing unit, a seed planting unit, and a transceiver. The second vehicle comprises at least one soil elevation sensor, a control and processing unit, and a transceiver. The first vehicle is configured to plant crop seeds on an agricultural field with the seed planting unit. The at least one seed position sensor of the first vehicle is configured to collect seed geoposition data of the crop seeds impinging on the soil surface from the seed planting unit during planting. The control and processing unit of the first vehicle is configured to receive the seed position data of the at least one seed position sensor to generate a crop seed map of the agricultural field. The at least one soil elevation sensor from the second vehicle is configured to collect soil elevation data, the soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field at a first time point and at a second time point which is later than the first time point. The control and processing unit of the second vehicle is configured to receive the soil elevation data from the at least one soil elevation sensor and to generate soil profile maps of the agricultural field at at least two different time points. The control and processing unit of the first vehicle is configured to utilize the transceiver to transmit the crop seed map of the agricultural field from to the second vehicle. The control and processing unit of the second vehicle is configured to utilize the transceiver to receive the crop seed map of the agricultural field from the first vehicle. The control and processing unit of the second vehicle is configured to compare the soil surface profile maps and the seed map to identify differences in the soil elevation profile that are not associated with seed growth of the planted seeds on the agricultural field and to generate a weed control agent spray map. 
     In an example, the system for weed control management comprises a first vehicle which further comprises at least one soil elevation sensor. The at least one soil elevation sensor of the first vehicle is configured to collect soil elevation data, the soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field for the first time point. The control and processing unit of the first vehicle is configured to receive the soil elevation data from the at least one soil elevation sensor to generate a soil surface profile map of the agricultural field at a first time point. The control and processing unit of the first vehicle is configured to utilize the transceiver to transmit the soil surface profile map of the agricultural field at a first time point to the second vehicle. The control and processing unit of the second vehicle is configured to utilize the transceiver to receive the soil surface profile map of the agricultural field at a first time point from the first vehicle. 
     In an example, the system for weed control management comprises a second vehicle which further comprises at least one weed control agent spray unit. The at least one weed control agent spray unit is configured to eject a weed control spray agent. The control and processing unit of the second vehicle is configured to control the at least one weed control agent spray unit according to the weed control agent spray map. 
     According to another aspect, there is provided a computer program product, which when executed by a processor is configured to carry out the method of the first aspect. 
     Advantageously, the benefits provided by any of the above aspects equally apply to all of the other aspects and vice versa. 
     The above aspects and examples will become apparent from and be elucidated with reference to the embodiments described hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments will be described in the following with reference to the following drawings: 
         FIG.  1    shows a schematic example of the generation of a weed control agent spray map; 
         FIG.  2   a   ) and b) show schematic examples of the weed germination process (from a side view perspective) and the soil elevation patterns generated by the weed germination process (from a top view perspective); 
         FIG.  3    shows a schematic set up of an example of a vehicle ( 100 ) for weed control management; 
         FIG.  4    shows a schematic set up of an example of a vehicle ( 200 ) for weed control management; 
         FIG.  5    shows a schematic set up of an example of a system ( 300 ) for weed control management; 
         FIG.  6    shows a schematic set up of a detailed example of a vehicle ( 100 ) for weed control management (from a side view perspective); 
         FIG.  7    shows a schematic set up of a detailed example of a vehicle ( 200 ) for weed control management (from a side view perspective); and 
         FIG.  8    shows a schematic set up of an example of a computer program product ( 400 ) for weed control management. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The invention relates in a first embodiment to a method  10  for weed control management. The method comprises the steps of: 
     a) acquiring geopositional information of planted crop seeds on an agricultural field and generating a crop seed map,
 
b) acquiring soil elevation data and the corresponding geopositional information of the soil elevation on the agricultural field where the crop seeds have been planted or are being planted at at least two different time points and generating soil surface profile maps of the agricultural field, the soil surface profile maps showing the soil surface profiles at the at least two different time points,
 
c) comparing the soil surface profile maps and the crop seed map to identify differences in the soil elevation profile that are not associated with seed growth of the planted seeds on the agricultural field,
 
d) generating a weed control agent spray map on the basis of the differences in the identified soil elevations on the agricultural field that are not associated with seed growth of the planted crop seeds on the agricultural field.
 
     In an example, the term “geopositional information” refers to the real-world geographic location e.g. as represented in geographic coordinates. 
     In an example, the terms “where the crop seeds have been planted or are being planted” refer to time points shortly after planting. E.g. when crops seeds have been planted with a vehicle with planting equipment on the front side of the vehicle and for which soil elevation data can be acquired in the same operational process with sensors at the rear side of the same vehicle. The time point can also be later e.g. a view days after planting. The data can also be acquired with a vehicle that is different to the seed planting vehicle. 
     In an example, the resolution of the geopositional information is ±10 cm, more preferably ±5 cm, and even more preferably ±2 cm, which can be obtained by a seed position sensor with a location determining means system such as a GPS-Real Time Kinetic (RTK) system. 
     In an example, information about the geopositional information of planted crop seeds on an agricultural field can be acquired with a camera, laser scanner, a one-dimensional line sensor for detecting seeds, a light beam, and a thermosensor for detecting heated-up seeds together with a position-determining system. US2014/0076216A1 discusses a method for precision drilling of seed grains and the registration of the seed position in a chart. 
     In an example, the crop seed map refers to the registration of the seed position in a chart particularly in the form of a at least two-dimensional (or alternatively three-dimensional) display of the crop seed geopositional distribution on an agricultural field after planting. 
     In an example, the soil elevation data and the corresponding geopositional information of the soil elevation on the agricultural field is acquired with a lidar sensor, a parallax laser rangefinder sensor, a stereo vision sensor, an IR reflectance sensor, a time of flight sensor, an ultrasonic sensor, a radar sensor. 
     In an example, a lidar sensor is used. 
     In an example, a 3D lidar sensor is used 
     In an example, a lidar sensor together with a camera is used. The camera can e.g. identify green parts of weeds that have already emerged and this information can be taken into account for the generation of the weed control agent spray map. 
     In an example, the camera is configured to operate over the visible wavelength range. In an example, the camera is configured to operate in the near infrared range. In an example, the camera is monochromatic. In an example, the camera is configured to acquire colour information such RGB. In an example, the camera is configured to acquire hyperspectral information. 
     In an example, a plurality of lidar scans at various locations across the agricultural field are acquired. This is done in order to provide a highly consistent lidar point density (number light detection and ranging measured points per unit area on a given target). One issue to consider for ground-based and/or close to the ground-based lidar sensoring is the potential unevenness of the point density over a scene where parts of the soil rendered closer to the scanner are more densely covered than the ones fare away. This can be addressed by various means such as for example by increasing the pulse repetition rate, changing the scan pattern, and/or the scan rate. 
     In an example, the soil elevation data and the corresponding geopositional information of the soil elevation on the agricultural field is acquired with a lidar sensor and with a position-determining system such as a GPS-Real Time Kinetic (RTK). 
     In an example, the at least two different time points refer to measurements of the soil elevation data and the corresponding geopositional information of the soil elevation at two different times with e.g. a time lag of e.g. a day, a week, 2 weeks, 3 weeks. 
     In an example, the soil elevation data is acquired on at a plurality of different time points and each compared to the previous soil elevation data. As an example, the soil elevation data is acquired on a daily basis. 
     In an example, a soil surface profile map refers a at least two-dimensional (or three-dimensional) display of the geopositional coordinates for the agricultural field, wherein for each geopositional coordinate the soil elevation amount is indicated (at the time of measurement). The data resolution of the geoposition (horizontal) is depending on the lidar and position determining means used and is preferably at least 2 cm, more preferably 1 cm and even more preferably below 1 cm. As concerns the measurement of soil elevation amount, todays lidar sensors have a resolution of a view millimeters to detect vertical differences which is sufficient to detect changes in the soil elevation profile indicating the germination and growth of weeds. 
     In an example, an algorithm is applied to correct for small geoposition shifts between two or more soil surface profile maps. 
     In an example, soil surface profile maps of at least two different time points are compared with each other (see  FIG.  1   ,  a, b ). This comparison reveals changes in the soil elevation amounts for the same geoposition over time on the agricultural field (see  FIG.  1   ,  d ). These differences can be further analysed with machine learning algorithms for patterns that relate to weed germination activities. When weeds germinate the shoot pushes against the soil above the shoot. The soil elevates above the shoot (see  FIG.  2   a   , side view perspective). When analyzing these weed germination processes from above, patterns are revealed (see  FIG.  2   b    of a schematic illustration of potential patterns from a top view perspective) which can be distinguished from other soil elevation changing incidences such e.g. for example weather activities. Also other soil elevation changes not due to germinating weeds can be analysed in a similar way and e.g. be classified with machine learning algorithms. By overlaying the crop seed map with the soil profile maps at at least two different time points (see  FIG.  1     d ) weeds that germinate can be identified and be distinguished from planted crop seeds and soil elevation changes that occurred due to other reasons such as weather incidences. Then, a weed control agent spray map can be generated (see  FIG.  1     e ). The weed control agent spray map is (at least) a two-dimensional (or three-dimensional) display of weed (germination and emergence) geopositional distribution on an agricultural field where a weed control agent can be applied to appropriately control the weeds on the field. 
     In an example, analysis of the soil elevation data/soil profile map comprises utilisation of a machine learning algorithm. 
     In an example, the machine learning algorithm comprises a decision tree algorithm. 
     In an example, the machine learning algorithm comprises an artificial neural network. 
     In an example, the machine learning algorithm has been taught on the basis of a plurality of soil elevation profile maps. In an example, the machine learning algorithm has been taught on the basis of a plurality of soil elevation profile maps containing soil elevation patterns due to at least one type of weed, various soil types and various soil moisture degrees. In an example, the machine learning algorithm has been taught on the basis of a plurality of soil elevation profile maps containing soil elevation patterns of a plurality of weeds, various soil types and various soil moisture degrees. 
     In an example, a machine learning algorithm similar as discussed above is used to identify weeds that have already emerged, the species of the weeds (at least monocotyledon/dicotyledon), growth stadium/size and geolocation. 
     In an example, data of weeds that have already emerged is used to generate the weed control spray map. 
     In an example, a radius of 20 cm, preferably 10 cm, more preferably 5 cm and even more preferably 3 cm around an individual crop seed is marked on the weed control agent spray map to be not sprayed with a weed control agent. 
     According to an example, the data for the crop seed map and the soil surface profile map showing the soil surface profile at the first time point are acquired on the agricultural field with an agricultural vehicle at the same time. 
     In an example, the data for the crop seed map for a certain geolocation is acquired prior to the acquisition of the data for the soil surface profile at the first time point for the same geolocation (however, with the same vehicle). As an example  FIG.  6    shows a vehicle, where the data for the crop seed map (e.g. a camera, see  111  in  FIG.  6   ) for a certain location is acquired prior to the acquisition of the data for the soil surface profile at the first time point (see  112  in  FIG.  6    and the moving direction of the vehicle  100 ) for the same location. In seed planting vehicles there is often a furrow closer  133  after the crop seeds have been put into the furrow which presses on the soil and closes the furrow. Therefore, it is necessary to acquire the data for the soil elevation after seed planting operations have been conducted. 
     In an example, the term “at the same time” refers to one continuous operation on the agricultural field with the same vehicle. 
     In an example, the “first time point” is shortly after the crop seeds have been planted. 
     According to an example, the method for weed control management further comprises step e) application of a weed control agent to the agricultural field according to the weed control agent spray map. 
     In an example, the weed control agent is a selective and/or a non-selective weed control agent. Thus, due to the precise weed control management method it is also possible to apply non-selective herbicides. 
     In an example, the weed control agent is a pre-emergence and/or an early post-emergence weed control agent. 
     According to an example, the method for weed control management the steps a) to e) are performed prior to the emergence and/or during the emergence of a plurality of shoots of the crop seeds and/or weeds on the agricultural field. 
     In an example, the method for weed control management is applied within the first two months, preferably within the first four weeks after planting of the crop seeds on the agricultural field. 
     According to an example, the method for weed control management acquires the geopositional information of the planted crop seeds on the agricultural field by at least one sensor that is configured to record geopositional information of the crop seeds impinging on the soil during planting of the crop seeds. 
     In an example, the at least one sensor that is configured to record geopositional information of the crop seeds impinging on the soil during planting of the crop seeds is selected from the group of a camera, laser scanner, a one-dimensional line sensor for detecting seeds, a light beam, and/or a thermosensor for detecting heated-up seeds; all together (and in synchronization) with a position determining means. 
     In an example, a location determining means comprise one or more of a GPS, an inertial navigation systems, or an image based location system. The GPS system is preferably a GPS-Real Time Kinetic (RTK) system. The location can be a geographical location, with respect to a precise location on the ground, or can be a location on the ground that is referenced to another position or positions on the ground, such as a boundary of an agricultural field. In other words, an absolute geographical location can be utilized or a location on the ground that need not be known in absolute terms, but that is referenced to a known location can be used. 
     In an example, the location is an absolute geographical location. 
     In an example, if a camera is used the location is a location that is determined with reference to a known location or locations. In other words, an image can be determined to be associated with a specific location on the ground, without knowing its precise geographical position, but by knowing the location where an image was acquired with respect to known position(s) on the ground the location where imagery was acquired can be logged. In other words, absolute GPS derived locations of where a vehicle has acquired imagery of the ground could be provided, and/or the locations of where imagery was acquired relative to a known position such as a field boundary could be provided, which again enables the control and processing unit to determine the exact positions where imagery was acquired because they would know the absolute position of the field boundary. 
     In an example, a GPS unit is used to determine, and/or is used in determining, the location, such as e.g. the location of the camera when specific images were acquired. 
     In an example, an inertial navigation unit is used alone, or in combination with a GPS unit, to determine the location, such as e.g. the location of the camera when specific images were acquired. 
     According to an example, the method for weed control management acquires the soil elevation data and the corresponding geopositional information of the soil elevation on the agricultural field is acquired with a sensor that is configured to generate pulses of light towards the soil surface and to measure the time for any reflections together (and in synchronization) with location determining means. 
     In an example, the sensor that is configured is configured to generate pulses of light towards the soil surface and to measure the time for any reflections is selected from the group of a lidar sensor, a parallax laser rangefinder sensor, a stereo vision sensor, an IR reflectance sensor, a time of flight sensor, an ultrasonic sensor, a radar sensor. 
     In an example, a lidar sensor is used. 
     In an example, a 3D lidar sensor is used. 
     In an example, a lidar sensor together with a camera is used. The camera can e.g. identify green parts of weeds that have already emerged, and this information can be taken into account for the generation of the weed control agent spray map. 
     In an example, the lidar sensor and/or the camera can acquire data/images of the soil close to the nadir (straight downwards) for optimum resolution. 
     In an example, the lidar sensor and/or the camera can acquire data/images of the soil closer to the horizontal plane (approximately 20-40° from the horizontal). 
     In an example, data/images of the same geoposition on the agricultural field are acquired from different angles such as close to the nadir and approximately 20-40° from the horizontal. For weeds that have already emerged dicotyledon plants imaging close to the nadir would be most effective while for monocotyledon plants imaging closer to the horizontal plane would be most effective. 
     In an example, the location determining means comprise one or more of a GPS, an inertial navigation systems, or an image based location system (similarly as described above the in the context of the crop seed position sensor). It is also possible that a plurality of sensors use together one location determining means to synchronise geopositional information to each individual sensor data. 
       FIG.  3    shows a schematic example of a vehicle  100  for weed control management. The vehicle  100  for weed control management comprises a plurality of sensors  110  comprising at least one seed position sensor  111  and at least one soil elevation sensor  112 ; a control and processing unit  120 , and a seed planting unit  130 . The vehicle  100  is configured to plant crop seeds on an agricultural field with the seed planting unit  130 . The at least one seed position sensor  111  is configured to collect seed geoposition data of the crop seeds impinging on the soil surface from the seed planting unit  130  during planting. The control and processing unit  120  is configured to receive the seed geoposition data from the at least one seed position sensor  111  to generate a crop seed map of the agricultural field. The at least one soil elevation sensor  112  of the vehicle is configured to collect soil elevation data, the soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field. The control and processing unit  120  is configured to receive the soil elevation data from the at least one soil elevation sensor  112  to generate a soil surface profile map of the agricultural field, wherein the soil surface profile map shows the soil surface profile at a first time point. The seed position data and the soil elevation data are acquired at the same instance when the plant crop seeds are planted on an agricultural field with the seed planting unit of the vehicle. 
     In an example, the vehicle  100  is an Unmanned Ground Vehicle (UGV), a tractor, a seed planter vehicle, an Unmanned Aerial Vehicle (UAV), preferably an UGV, tractor or seed planter vehicle. 
     In an example, the at least one seed position sensor  111  is (as described above for the method) preferably selected from the group of a camera, laser scanner, a one-dimensional line sensor for detecting seeds, a light beam, and/or a thermosensor for detecting heated-up seeds; all together with a position determining means. Appropriate position determining means are discussed in context with the method. 
     In an example, the at least one soil elevation sensor  112  is (as described above for the method) preferably selected from the group of a lidar sensor, a parallax laser rangefinder sensor, a stereo vision sensor, an IR reflectance sensor, a time of flight sensor, an ultrasonic sensor, a radar sensor. 
     In an example, a lidar sensor is used. 
     In an example a 3D lidar sensor is used 
     In an example, a lidar sensor together with a camera is used. 
     In an example, the control and processing unit  120  can completely be part of the vehicle or can have external at least on addition external processing unit and the control and processing unit  120  communicates via wireless data transmission with the external processing unit (which can be an external computer, cloud etc.). 
     In an example, the seed planting unit  130  comprises at least one seed dosing system  132  configured to deposit the crop seed onto the soil. 
     In an example, the seed planting unit  130  further comprises at least one furrow opener  131  configured to open a furrow in the soil. 
     In an example, the seed planting unit  130  further comprises at least one furrow closer  133  configured to close the furrow. 
     In an example, the furrow closer  133  is a wheel. 
     In an example, the seed is deposited by the seed dosing system  132  into the furrow as generated by the at least one furrow opener  131 . 
     In an example the seed planting unit  130  and the at least one seed position sensor  111  are attached to/positioned closer to the front of the vehicle in comparison to the at least one soil elevation sensor  112  which is attached to/positioned closer to the rear side of the vehicle and preferably behind the back wheels of the vehicle. 
     According to an example, the vehicle  100  for weed control management further comprises: an output unit  140 . The output unit  140  is configured to receive the crop seed map of the agricultural field and the soil surface profile map of the agricultural field from the control and processing unit  120 . The output unit  140  is configured to output the crop seed map of the agricultural field and the soil surface profile map of the agricultural field. 
     In an example, the output unit comprises a monitor, a printer, a screen, an information monitoring device and/or any other information monitoring medium. 
       FIG.  4    shows a schematic example of a vehicle  200  for weed control management. The vehicle  200  for weed control management comprises at least one soil elevation sensor  210 , a control and processing unit  220 , and a transceiver  230 . The at least one soil elevation sensor  210  is configured to collect soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field at a first time point. The at least one soil elevation sensor  210  is configured to collect soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field at a second time point which is after the first time point. The control and processing unit  220  is configured to receive the soil elevation data from the at least one soil elevation sensor  210  and to generate soil surface profile maps of the agricultural field at at least two different time points. The control and processing unit  220  is configured to utilize the transceiver  230  to receive a crop seed map of the agricultural field. The control and processing unit  220  is configured to compare the soil surface profile maps and the crop seed map to identify differences in the soil elevation profile that are not associated with seed growth of the planted seeds on the agricultural field and to generate a weed control agent spray map. 
     In an example, the vehicle  200  is an Unmanned Ground Vehicle (UGV), a tractor, an Unmanned Aerial Vehicle (UAV), preferably an UAV or tractor. 
     In an example, the at least one soil elevation sensor  210  is a similar sensor as the one described in the context of the at least one soil elevation sensor  112 . 
     In an example, the crop seed map of the agricultural field has been generated by the first vehicle  100 . This information about the crop seed map is transmitted to the second vehicle  200  (e.g. from the first vehicle directly to the second vehicle or via data cloud or an external processing unit preferably via wireless communication). 
     According to an example, the vehicle  200  for weed control management comprises a control and processing unit  220  configured to utilize the transceiver  230  to receive the soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field at the first time point and/or the soil surface profile map of the agricultural field for the first time point. 
     In an example, the second vehicle  200  acquires soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field at a second time point (and not for the first time point). Similarly as with the crop seed map, the second vehicle  200  receives the soil elevation data and/or the soil surface profile map for the first time point from the first vehicle  100  (or another vehicle) directly or via data cloud or an external processing unit. When the second vehicle  200  comprises a weed control agent spray unit  250  it is possible that the vehicle acquires the soil elevation data for the second time point, receives all other data required to generate the weed control agent spray map with its transceiver, generated the weed control agent spray map and starts to control the weeds on the agricultural field with its weed control agent spray unit and this all in one operational procedure on the agricultural field. 
     According to another example, the vehicle  200  for weed control management comprises an output unit  240 . The output unit  240  is configured to receive the weed control agent spray map for the agricultural field from the control and processing unit  220 . The output unit  240  is configured to output the weed control agent spray map for the agricultural field. 
     In an example, the output unit  240  comprises a monitor, a printer, a screen, an information monitoring device and/or any other information monitoring medium. The output unit can also be another vehicle which receives the spray map in order to conduct the spraying operation. 
     In an example the vehicle  200  is an UAV and the information about the weed control agent spray map of the agricultural field is sent via wireless communication to an output unit. 
     According to another example, the vehicle  200  for weed control management comprises at least one weed control agent spray unit  250 . The at least one weed control agent spray unit  250  is configured to eject a weed control spray agent. The control and processing unit  220  is configured to control the at least one weed control agent spray unit  250  according to the weed control agent spray map. 
     In an example, weed control spray unit  250  comprises at least one spray unit. The at least one spray unit is configured to spray a liquid. 
     In an example, a spray unit is e.g. a boom sprayer. 
     In an example, the term “control the at least one weed control agent spray unit” in the context of a spray unit refers to the control of the start of the spraying process and the control of the stop of the spraying process. 
     In an example, a spray unit comprises at least one liquid atomizer such as a hydraulic nozzle and/or at least one atomizing disc such as a spinning disc. 
     In an example, the at least one weed control agent spray unit comprises a, liquid atomizer, a liquid tank and at least one feed pipe. The liquid tank is configured to hold a liquid. The feed pipe is configured to transport the liquid from the liquid tank to the liquid atomizer. The liquid atomizer is configured to spray the liquid. 
     In an example, the term “liquid(s)” refer(s) to liquid(s) comprising chemical and/or biological based herbicidal active ingredients (such as a weed control agent as discussed herein before). 
     In an example, the control and processing unit is configured to control the at least one spray unit to apply the liquid either as a spray of fine droplets, a single jet, a single droplet, or a combination of these, depending on the preferred type of deposit. 
     According to another example, another embodiment of the invention relates to a weed control agent spray map generated according to the method of weed control management as described herein. 
     In an example, the weed control agent spray map is (at least) a two-dimensional (or three-dimensional) display of weed (germination and emergence) geopositional distribution on an agricultural field where a weed control agent can be applied to appropriately control the weeds on the field (see  FIG.  1   , d). 
     In an example, the information of the weed control agent spray map can be sent to a plurality of other vehicles (such as UAVs) which comprise spray units and are configured to apply herbicides according to the spray map at various locations on the agricultural field. 
       FIG.  5    shows a schematic example of a system  300  for weed control management. The system  300  for weed control management comprising a first vehicle  100  for weed control management and a second vehicle  200  for weed control management. The first vehicle comprises at least one seed position sensor  111 , a control and processing unit  120 , a seed planting unit  130 , and a transceiver  140 . The second vehicle comprises at least one soil elevation sensor  210 , a control and processing unit  220 , and a transceiver  230 . The first vehicle  100  is configured to plant crop seeds on an agricultural field with the seed planting unit  130 . The at least one seed position sensor  111  of the first vehicle is configured to collect seed geoposition data of the crop seeds impinging on the soil surface from the seed planting unit  130  during planting. The control and processing unit  120  of the first vehicle is configured to receive the seed position data of the at least one seed position sensor  111  to generate a crop seed map of the agricultural field. The at least one soil elevation sensor  210  from the second vehicle  200  is configured to collect soil elevation data, the soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field at a first time point and at a second time point which is later than the first time point. The control and processing unit  220  of the second vehicle  200  is configured to receive the soil elevation data from the at least one soil elevation sensor  210  and to generate soil profile maps of the agricultural field at at least two different time points. The control and processing unit  120  of the first vehicle is configured to utilize the transceiver  140  to transmit the crop seed map of the agricultural field from to the second vehicle  200 . The control and processing unit  220  of the second vehicle  200  is configured to utilize the transceiver  230  to receive the crop seed map of the agricultural field from the first vehicle  100 . The control and processing unit  220  of the second vehicle  200  is configured to compare the soil surface profile maps and the seed map to identify differences in the soil elevation profile that are not associated with seed growth of the planted seeds on the agricultural field and to generate a weed control agent spray map. 
     According to an example, the system  300  for weed control management comprises a first vehicle which comprises at least one soil elevation sensor  112 . The at least one soil elevation sensor  112  of the first vehicle is configured to collect soil elevation data, the soil elevation data comprising elevations amounts and the corresponding geopositional information of the soil elevations on the agricultural field for the first time point. The control and processing unit  120  of the first vehicle is configured to receive the soil elevation data from the at least one soil elevation sensor  112  to generate a soil surface profile map of the agricultural field at a first time point. The control and processing unit  120  of the first vehicle is configured to utilize the transceiver  140  to transmit the soil surface profile map of the agricultural field at a first time point to the second vehicle  200 . The control and processing unit  220  of the second vehicle  200  is configured to utilize the transceiver  230  to receive the soil surface profile map of the agricultural field at a first time point from the first vehicle  100 . 
     In an example, the second vehicle  200  does not need to generate the soil surface profile map of the agricultural field at a first time point but receives this information from the first vehicle  100  or another vehicle. 
     According to an example, the system  300  for weed control management comprises a second vehicle  200  which comprises at least one weed control agent spray unit  250 . The at least one weed control agent spray unit  250  is configured to eject a weed control spray agent. The control and processing unit  220  of the second vehicle  200  is configured to control the at least one weed control agent spray unit  250  according to the weed control agent spray map. 
       FIG.  6    shows a schematic set up of a detailed example of a vehicle  100  for weed control management. The vehicle shown is a ground vehicle such as a tractor and comprises a seed planting unit  130  with a furrow opener  132 , a seed dosing system  132  and a furrow closer  133 . The crop seed position sensor  111  is a camera which records the geoposition of the crop seeds in the soil. The camera is synchronised with a GPS system. The vehicle comprises a soil elevation sensor  112  such as a lidar scanner at the rear of the vehicle. Soil elevations are scanned with the lidar sensor (for the first time point) after the planting process with the planting unit  130  has been terminated. 
       FIG.  7    shows a schematic set up of a detailed example of a vehicle  200  for weed control management. The vehicle  200  in this example is an UAV. The UAV flies over an agricultural field and scans the ground beneath with a soil elevation sensor  210  such as a 3D lidar sensor ( FIG.  7     a ). A plurality of sensors on the UAV continuously record the position, altitude, height above the ground, and orientation of the lidar sensor to allow accurate position information to be included in the lidar image, which would be a detailed 3-D map of the soil surface. The UAV receives crop seed map data and soil elevation data for another earlier time point with the transceiver  230 . The control and processing unit (not shown) uses the received information as well as the information from the soil elevation sensor  210  to assess where a herbicidal active ingredient needs to be applied to the soil (and therefore generates a spray map). Thus, comparison and analysis of two or more lidar images from the same agricultural field but acquired over a period of one or more days would show any differences from local changes in the height of the soil. The control and processing unit would analyse for changes indicative of growth underneath the soil surface from germinating seeds and catalogue the locations of these. An algorithm can be applied to correct for small geoposition shifts between two or more soil surface profile maps. The control and processing unit would also analyse growing plants, identify the species of plant, and if identified as an unwanted weed catalogue both the species, size and location of these. An algorithm can be applied to identify and eliminate false detections. The UAV  200  can also send its acquired soil elevation data to an external processing unit which does generate the spray map and send it back to the UAV  200  for spraying or another specialized spray UAV as shown in  FIG.  7     c .  FIG.  7     b  indicates that the same UAV can use the spray map to directly control the weeds via its weed control unit  250 . Alternatively, another UAV specialized to apply a weed control agent can receive the spray map from the UAV  200  and apply a weed control agent to the soil (see  FIG.  7     c ). 
     In another exemplary embodiment, a computer program or computer program product is provided that is characterized by being configured to execute the method steps of the method according to one of the preceding embodiments, on an appropriate system. 
       FIG.  8    shows a schematic set up of an example of a computer program product  400  for weed control management. The computer program product  400  for weed control management, which when executed by a processor is configured to carry out the steps of: 
     a) receiving  410  geopositional information of planted crop seeds on an agricultural field,
 
b) generating  420  a crop seed map on the basis of the information received in step a),
 
c) receiving  430  soil elevation data and the corresponding geopositional information of the soil elevation on the agricultural field where the crop seeds have been planted or are being planted at at least two different time points,
 
d) generating  440  soil surface profile maps of the agricultural field, the soil surface profile maps showing the soil surface profiles at the at least two different time points on the basis of the information received in step c),
 
e) comparing  450  the soil surface profile maps and the crop seed map,
 
f) identifying  460  differences in the soil elevation profile that are not associated with seed growth of the planted seeds on the agricultural field,
 
g) generating  470  a weed control agent spray map on the basis of the differences in the identified soil elevations on the agricultural field that are not associated with seed growth of the planted crop seeds on the agricultural field.
 
     According to an example computer program product  400  for weed control management comprising the additional step: 
     e) instructing  480  a vehicle to apply a weed control agent to the agricultural field according to the weed control agent spray map. 
     The computer program product might be stored on a computer unit, which might also be part of an embodiment. This computing unit may be configured to perform or induce performing of the steps of the method described above. Moreover, it may be configured to operate the components of the above described vehicle(s) and/or system. The computing unit can be configured to operate automatically and/or to execute the orders of a user. A computer program may be loaded into a working memory of a data processor. The data processor may thus be equipped to carry out the method according to one of the preceding embodiments. 
     This exemplary embodiment of the invention covers both, a computer program that right from the beginning uses the invention and computer program that by means of an update turns an existing program into a program that uses invention. Further on, the computer program product might be able to provide all necessary steps to fulfil the procedure of an exemplary embodiment of the method as described above. 
     According to a further exemplary embodiment of the present invention, a computer readable medium, such as a CD-ROM, USB stick or the like, is presented wherein the computer readable medium has a computer program product stored on it which is/can be a computer program product as described by the preceding section. A computer program may be stored and/or distributed on a suitable medium, such as an optical storage medium or a solid state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the internet or other wired or wireless telecommunication systems. 
     However, the computer program may also be presented over a network like the World Wide Web and can be downloaded into the working memory of a data processor from such a network. 
     According to a further exemplary embodiment of the present invention, a medium for making a computer program product available for downloading is provided, which computer program product is arranged to perform a method according to one of the previously described embodiments of the invention. 
     It has to be noted that embodiments of the invention are described with reference to different subject matters. In particular, some embodiments are described with reference to method type claims whereas other embodiments are described with reference to the vehicle, spray map, and/or system type claims. However, a person skilled in the art will gather from the above and the following description that, unless otherwise notified, in addition to any combination of features belonging to one type of subject matter also any combination between features relating to different subject matters is considered to be disclosed with this application. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing a claimed invention, from a study of the drawings, the disclosure, and the dependent claims. 
     In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfil the functions of several items re-cited in the claims. The mere fact that certain measures are re-cited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.