Ultrasonic Tree Measurement System

Abstract

A system and method for calculating a plant extent and a plant density of vegetation is provided. An ultrasonic signal is transmitted by one or more transducers towards the vegetation. A plurality of echo signals are received by the one or more transducers as reflections of the ultrasonic signal. A plant extent of the vegetation is calculated based on a first echo signal of the plurality of echo signals and a last echo signal of the plurality of echo signals. A plant density is calculated based on the plurality of echo signals. A plant extent and a plant density of the vegetation are output.

Description

[Technical field]

[0001] This application claims priority to U.S. Provisional Application No. 63 / 261,197, filed September 14, 2021, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates generally to tree measurement systems, and more particularly to an ultrasonic tree measurement system for measuring plant extent and plant density of vegetation. [Background technology]

[0003] A sprayer is an agricultural machine used to apply liquids, such as herbicides, pesticides, fertilizers, and water, to vegetation. As an example, in a vineyard, a sprayer is utilized to apply such liquids to the grape vines. In order to provide the grape vines with an optimal amount of liquid, the spread and density of the grape vines must be determined.

[0004] Conventional measurements of grapevines have generally been limited to measurements of the canopy using LIDAR (light detection and ranging) sensors or basic ultrasonic sensors. However, measurements representative of the internal structure or depth of the grapevine are not captured by such conventional measurements.

[0005] Other methods exist to measure the total volume of a vine, but they require sensors to measure from both sides of the row, a slower and less efficient process. Scanning from both sides requires running along both sides of the vine or supporting a sensor on both sides of the vine. If measurements from both sides of the vine are used to calculate the vine width, a common reference frame of position is required, such as a highly accurate global positioning system (GPS) positioning (which can be subject to error). Summary of the Invention

[0006] According to one or more embodiments, a system and method are provided for calculating a plant extent and a plant density of vegetation. An ultrasonic signal is transmitted by one or more transducers towards the vegetation. A plurality of echo signals are received as reflections of the ultrasonic signal by the one or more transducers. A plant extent of the vegetation is calculated based on a first echo signal of the plurality of echo signals and a last echo signal of the plurality of echo signals. A plant density of the vegetation is calculated based on the plurality of echo signals. A plant extent and a plant density of the vegetation are output.

[0007] In one embodiment, the plurality of echo signals are received within a time window. A plant density of the vegetation may be calculated based on a quantity of the plurality of echo signals received within the time window or based on an intensity of the plurality of echo signals received within the time window. A vegetation extent may be calculated by calculating a first distance between the transducer and the vegetation based on a first echo signal and calculating a second distance between the transducer and the vegetation based on a last echo signal. The vegetation extent is determined as a difference between the first distance and the second distance.

[0008] In one embodiment, a particular echo signal associated with one or more non-vegetative structures among the plurality of echo signals is detected based on at least one of 1) a distance determined based on the particular echo signal, or 2) a strength of the particular echo signal. The particular echo signal is removed from the plurality of echo signals.

[0009] In one embodiment, a map of vegetation is generated based on at least one of plant extent or plant density using global positioning system (GPS) data.

[0010] In one embodiment, the substance is applied to the vegetation in a variable amount that is determined substantially in real time based on at least one of plant area or plant density.

[0011] In one embodiment, the multiple echo signals are normalized based on the distance between one or more transducers and the vegetation.

[0012] In one embodiment, the one or more transducers are attached to the agricultural machine.

[0013] These and other advantages of the present invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 illustrates an exemplary agricultural field in which a tree measurement system can measure the plant extent and plant density of vegetation according to one or more embodiments. [Diagram 2] FIG. 2 illustrates vegetation in which a tree measurement system can measure plant extent and plant density according to one or more embodiments. [Diagram 3] FIG. 3 illustrates a schematic diagram of an exemplary agricultural machine according to one or more embodiments. [Figure 4] FIG. 4 illustrates a method for determining plant extent and plant density of vegetation according to one or more embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Embodiments described herein provide a tree measurement system comprising one or more ultrasonic sensors for estimating plant extent and / or plant density of vegetation (e.g., rows of grape vines) in an agricultural field, an example of which is shown in FIG.

[0016] FIG 1 illustrates an agricultural land 100 in which a tree measurement system, according to one or more embodiments, can measure the plant spread and plant density of vegetation. As shown in FIG 1, the agricultural land 100 is a vineyard with rows of grape vines 102. However, the agricultural land 100 may be any agricultural land with any suitable type of vegetation (e.g., apple trees, tomato plants, etc.). According to one embodiment, the tree measurement system may be configured to measure the plant spread and / or plant density of the rows of grape vines 102.

[0017] FIG. 2 illustrates vegetation 200 for which a tree measurement system can measure plant spread and plant density, according to one or more embodiments. Plant spread refers to the lateral size of the vegetation. For example, as shown in FIG. 2, plant spread can represent the lateral distance 202 of the vegetation 200. Plant density refers to the amount of plant matter (e.g., leaves, branches, fruit) between the plant spreads. For example, plant density can represent the amount of plant matter 204 within the distance 202.

[0018] The tree measurement system includes one or more ultrasonic sensors, or transducers, for transmitting ultrasonic signals to a particular vegetation row and receiving multiple echo signals reflected from the ultrasonic signals to determine the vegetation extent and density of the vegetation row. Information regarding the time of arrival and signal strength of each echo signal is recorded. The echo signals are, for example, reflections of the ultrasonic signal from leaves, branches, and other tree bodies (and potentially non-tree bodies) in the vegetation row. The information collected by the ultrasonic sensors may be used to represent, for example (but not limited to), vegetation extent and density, as well as other suitable indicators, such as distance to tree cover. The vegetation extent may be quantified based on the first and last echo signals received during a time window. The vegetation density may be quantified based on the number of reflected echo signals received during the time window, or the amount of energy or intensity of the reflected signals received during the time window.

[0019] In one embodiment, the tree measurement system may be implemented in an agricultural machine. For example, the tree measurement system may be implemented in a sprayer to provide information to a variable spray rate control system for varying real-time application rates of liquid based on the amount of tree mass detected. An exemplary agricultural machine is shown in FIG.

[0020] 3 illustrates a schematic diagram of an example agricultural machine 322 including a tree measurement system 302 for measuring plant extent and plant density of vegetation 324 according to one or more embodiments. In one embodiment, agricultural machine 322 is a sprayer. However, agricultural machine 322 may be other suitable agricultural machines. In one example, vegetation 324 comprises vine rows 102 of FIG. 1 or vegetation 200 of FIG. 2. However, vegetation 324 may comprise other types of vegetation.

[0021] The measurement system 302 may include one or more processors 306 communicatively connected to a memory 314, a storage device 304, a display device 308, and an input / output device 310. The storage device 304 may store a number of modules representing functions of the tree measurement system 302. In one embodiment, the storage device 304 stores a measurement module 316 for measuring plant spread, plant density, and other indices of vegetation 324. Each module may be implemented as computer program instructions (e.g., code) stored in the storage device 304 and may be loaded into the memory 314 and executed by the processor 306 when execution of the computer program instructions is desired.

[0022] In operation, the measurement module 316 operates in cycles of transmission and reception. During the transmission phase, the processor 306 commands the pulse generator 318 to generate an electrical signal that is converted into a single ultrasonic signal 326 (represented as a separate signal to illustrate processing of the vegetation) and transmitted by one or more transducers 312 toward the vegetation 324. In one embodiment, the transducer 312 transmits the ultrasonic signal 326 toward the side of the vegetation 324 (e.g., the side of a vine). This embodiment does not transmit the ultrasonic signal 326 from the top down toward the top of the vegetation 324, and therefore requires additional processing. In another embodiment, in addition to the transducer 312 transmitting the ultrasonic signal 326 toward the side of the vegetation 324, an additional transducer may be used to transmit the ultrasonic signal 326 from the top down toward the top of the vegetation 324, and the reflected signal may be used to determine plant density or calculate other metrics of interest (e.g., tree height). As used herein, a transducer refers to a single device for transmitting and receiving a signal, but also to a pair of separate devices, one for transmitting a signal and the other for receiving the signal. In one embodiment, the ultrasonic signal 326 is an ultrasonic pulse having a duration of, for example, about 70 milliseconds to 320 microseconds. The radiation pattern of the ultrasonic signal is cone-shaped, centered on the transducer 312 and radiating outwardly as the ultrasonic signal propagates from the transducer 312. The ultrasonic signal 326 strikes one or more objects (e.g., vegetation 324) and returns as multiple echo signals 328 of the ultrasonic signal 326.

[0023] During the receive phase, a predefined receive window is opened for a period of time during which multiple echo signals 328 of the ultrasonic signal 326 are expected to be received by the transducer 312. The receive window may be of any suitable length of time that allows the echo signals of the ultrasonic signal to be received by the transducer 312. For example, the receive window may be of 10 millisecond duration. The transducer 312 receives the ultrasonic echo signal 328 and converts the ultrasonic echo signal 328 into an electrical signal. The electrical signal is passed to the amplifier circuit 320, where the electrical signal is amplified for processing by the processor 306. While the multiple echo signals 328 are depicted in FIG. 3 as four echo signals, the multiple echo signals may comprise any number of echo signals greater than one.

[0024] The processor 306 calculates the plant extent and plant density of the vegetation 324. In one embodiment, the plant extent of the vegetation 324 is determined by calculating a first distance between the transducer and the vegetation based on a first echo signal received during the time window, and calculating a second distance between the transducer and the vegetation based on a last echo signal received during the time window. The processor 306 calculates the first and second distances between the transducer 312 and the vegetation 324 based on the elapsed time between the transmission of the ultrasonic signal 326 and the reception of each echo signal 328. The plant extent of the vegetation 324 is then determined as the difference between the first and second distances. In one embodiment, the plant density of the vegetation 324 is calculated based on the number of the multiple echo signals 328 received during the time window or based on the intensity of the multiple echo signals 328 received during the time window. For example, the plant density of the vegetation 324 may be calculated as the sum of the energies of the echo signals 328. The energy of an echo signal 328 may be calculated by multiplying the duration of the echo signal by the amplitude of the echo signal. In one embodiment, for each echo signal 328, the amplitude is normalized based on the distance acquired to account for the distribution of the ultrasonic energy of the echo signal in the environment (e.g., the amplitude is inversely proportional to the square of the distance).

[0025] In one embodiment, the measurement module 316 operates continuously by repeatedly performing cycles of transmitting and receiving at periodic and discrete intervals, which may be of any suitable length of time, such as, for example, every 15-35 milliseconds.

[0026] In one embodiment, an ultrasound signal 326 is transmitted and an echo signal 328 is received as described in US Pat. No. 8,843,283, entitled "Height Control," the disclosure of which is incorporated herein by reference in its entirety.

[0027] In one embodiment, the transducer 312 of the tree measurement system 302 comprises a single ultrasonic sensor attached to a central portion of the row of vegetation 324 to calculate plant width and density to fully represent the vegetation 324. In other embodiments, the transducer 312 of the tree measurement system 302 comprises two or more ultrasonic sensors. For example, a sensor array may be positioned to capture information from the entire height of the row of vegetation 324. In another example, a sensor array may be used to simultaneously view two rows of vegetation 324 (as the tree measurement system moves between the two rows).

[0028] In one embodiment, a particular echo signal associated with a non-vegetative structure among the plurality of echo signals 328 is detected based on a distance determined based on the particular echo signal or based on an intensity of the particular echo signal. An example of a non-vegetative structure includes a wire support on which grapevines typically grow. The transmission of an ultrasonic signal toward a grapevine vine may result in a particular echo signal reflecting from the wire support. The particular echo signal may be detected or removed from the plurality of echo signals 328. The particular echo signal corresponding to the non-vegetative structure may be detected based on a known distance from the transducer 312 to the non-vegetative structure, a known pulse width corresponding to the echo signal reflecting from the non-vegetative structure, and / or a signal amplitude corresponding to the echo signal reflecting from the non-vegetative structure. In one embodiment, the distance, pulse width, and signal amplitude of the particular echo signal corresponding to the wire support may be identified by capturing a baseline ultrasonic scan in which the vegetation coverage is substantially zero (or below a threshold distance), indicating the absence of vegetation. The distance, pulse width, and signal amplitude of the echo signal reflecting from the wire support may be captured and used to identify a particular echo signal corresponding to the wire support from the plurality of echo signals 328. The particular echo signal corresponding to a non-vegetative structure may be subtracted from the results. For example, the plurality of echo signals 328 may be digitized (by recording the echo distance, echo pulse width, and pulse amplitude). In this regard, the non-vegetative structures may be identified (by distance, pulse width, and / or amplitude) from the digitized echo signals and removed from the list of results.

[0029] In one embodiment, the tree measurement system 302 may be used to monitor the nature of a vineyard or tree. Plant extent and / or plant density may be combined with global positioning system (GPS) coordinate data to generate maps for agricultural planning purposes.

[0030] In one embodiment, the agricultural machine 322 includes a variable spray rate control system 330. The tree measurement system 302 can output the plant width and / or plant density to the variable spray rate control system 330 to modify a real-time application rate of herbicide, pesticide, fertilizer, water, or other substance (e.g., liquid, granular, or other product) based on the plant width and / or plant density.

[0031] The embodiments described herein measure vegetation extent and density based on multiple echo signals of ultrasonic transmissions. This is a much simpler process than traditional methods that require measurements from both sides of the row. Traditional IR and laser methods are not considered to perform adequately in their ability to measure through trees. An advantage of the embodiments described herein is the use of ultrasonic waves, which diffract and pass through tree structures and can provide information not available from light-based methods.

[0032] 4 illustrates a method 400 for measuring plant extent and plant density of vegetation according to one or more embodiments. The steps of method 400 may be performed using one or more suitable computing devices (e.g., using processor 306 of FIG. 3).

[0033] In step 402, ultrasonic signals are transmitted by one or more transducers toward vegetation. The one or more transducers may be transducers 312 of FIG. 3. In one embodiment, the vegetation comprises grape vines. However, the vegetation may comprise other suitable vegetation. The one or more transducers may be attached to or otherwise implemented in agricultural machinery, such as, for example, a sprayer, for spraying or applying a substance (e.g., herbicide, pesticide, fertilizer, or water) to the vegetation.

[0034] In step 404, a plurality of echo signals are received by one or more transducers as reflections of the ultrasonic signal. The plurality of echo signals are received during a time window.

[0035] In one embodiment, the multiple echo signals are normalized based on the distance between one or more transducers and the vegetation.

[0036] In one embodiment, a particular echo signal associated with a non-vegetative structure (e.g., a wire support) among the plurality of echo signals is detected based on at least one of a distance determined based on the particular echo signal or an intensity of the particular echo signal, and the particular echo signal is removed from the plurality of echo signals.

[0037] In step 406, a plant spread of the vegetation is calculated in any manner based on a first echo signal of the plurality of echo signals and a last echo signal of the plurality of echo signals. In one embodiment, the plant spread is calculated by calculating a first distance between the transducer and the vegetation based on a first echo signal received during a time window, and calculating a second distance between the transducer and the vegetation based on a last echo signal received during the time window. The plant spread is determined as the difference between the first distance and the second distance.

[0038] In step 408, the plant density of the vegetation is calculated in any manner based on the plurality of echo signals. In one embodiment, the plant density of the vegetation is calculated based on a quantity of the plurality of echo signals received during a time window. In another embodiment, the plant density of the vegetation is calculated based on a strength of the plurality of echo signals received during a time window.

[0039] It should be understood that it is not necessary to perform both steps 406 and 408 in method 400. Method 400 may be performed by performing step 406 without performing step 408, by performing step 408 without performing step 406, or by performing both steps 406 and 408.

[0040] At step 410, the plant extent and plant density are output. For example, the plant extent and plant density may be output by displaying the plant extent and plant density on a display device of the computer system, by storing the plant extent and plant density in a memory or storage device of the computer system, or by transmitting the plant extent and plant density to a remote computer system.

[0041] In one embodiment, at least one of the plant width or plant density is output to a variable spray rate control system of the agricultural machine, and a substance (e.g., herbicide, pesticide, fertilizer, or water) is applied to the vegetation in a variable rate determined substantially in real time based on at least one of the plant width or plant density.

[0042] In one embodiment, a map of vegetation is generated using GPS data and based on at least one of plant extent or plant density.

[0043] The systems, devices, and methods described herein may be implemented using digital circuitry or one or more computers using well-known computer processors, memory units, storage devices, computer software, and other components. Typically, a computer comprises a processor for executing instructions and one or more memories for storing instructions and data. A computer may include or be connected to one or more mass storage devices, such as one or more magnetic disks, internal hard disks, and removable disks, magneto-optical disks, optical disks, and the like.

[0044] The systems, apparatus, and methods described herein may be implemented using computers operating in a client-server relationship. Typically, in such a system, the client computers are located remotely from the server computer and interact over a network. The client-server relationship may be defined and controlled by computer programs running on each of the client and server computers.

[0045] The systems, devices, and methods described herein may be implemented in a network-based cloud computing system. In such a network-based cloud computing system, a server, or another processor, is connected to one or more client computers of a network communication network via a network. The client computers may communicate with the server, for example, via a network browser application residing and running on the client computers. The client computers may store and access data on the server via the network. The client computers may send requests for data or requests for online services to the server via the network. The server may perform the requested service and provide the data to the client computers. The server may also send data adapted to cause the client computers to perform a specified function, such as performing a calculation, displaying specified data on a screen, etc. For example, the server may send a request adapted to cause the client computers to perform one or more steps of the methods and workflows described herein. Certain steps of the methods and workflows described herein may be performed by the server, or another processor, in the network-based cloud computing system. Certain steps of the methods and workflows described herein may be performed by the client computers in the network-based cloud computing system. Certain steps of the methods and workflows described herein may be performed, in any combination, by servers and / or client computers in a network-based cloud computing system.

[0046] The systems, devices, and methods described herein may be implemented using a computer program product tangibly embodied in an information medium, e.g., a non-transitory machine-readable storage device, for execution by a programmable processor, and the methods and workflow steps described herein may be implemented using one or more computer programs executable by such a processor. A computer program is a collection of computer program instructions that may be used, directly or indirectly, in a computer to perform a particular activity or bring about a particular result. Computer programs may be written in any type of programming language, including compiled or interpreted languages, and may be deployed in any form, such as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0047] The tree measurement system 302 of FIG. 3 may comprise a computer for implementing the systems, devices, and methods described herein. The processor 306 controls the overall operation of the tree measurement system 302 by executing computer program instructions that define such operation. The computer program instructions may be stored in the storage device 304, memory 314, or other computer readable medium. Thus, the methods and workflow steps described herein, such as, for example, the method 400 of FIG. 4, may be defined by computer program instructions stored in the storage device 304, or memory 314, and controlled by the processor 306 executing the computer program instructions. For example, the computer program instructions may be implemented as computer executable code programmed by one of ordinary skill in the art to perform the methods and workflow steps described herein. Thus, execution of the computer program instructions causes the processor 306 to perform the methods and workflow steps described herein. The tree measurement system 302 may also include one or more network interfaces (not shown) for communicating with other devices over a network. The tree measurement system 302 may also include one or more input / output (I / O) devices 310 (eg, a display, keyboard, mouse, speakers, buttons, etc.) that enable user interaction with the tree measurement system 302 .

[0048] The processor 306 may include both general purpose and special purpose microprocessors and may be the sole processor or one of multiple processors in the tree measurement system 302. For example, the processor 306 may include one or more central processing units (CPUs). The processor 306 and / or the memory 314 may include, be supplemented by, or be integrated into one or more application specific integrated circuits (ASICs) and / or one or more field programmable gate arrays (FPGAs).

[0049] The storage device 304 and the memory 314 may include non-transitory computer-readable storage media. The storage device 304 and the memory 314 may include high-speed random access memory, such as dynamic random access memory (DRAM), static random access memory (SRAM), double data rate synchronous dynamic random access memory (DDR RAM), or other random access solid-state memory devices, and may further include one or more non-volatile memories, such as magnetic disk storage devices, internal hard disks, and semiconductor memory devices, such as removable disks, magneto-optical disk storage devices, optical disk storage devices, flash memory devices, erasable programmable read-only memories (EPPROMs), electrically erasable programmable read-only memories (EEPPROMs), compact disk read-only memories (CD-ROMs), digital versatile disk read-only memories (DVD-ROMs), or other non-volatile solid-state storage devices.

[0050] The input / output devices 310 may include peripherals such as a printer, a scanner, a display screen, etc. For example, the input / output devices 310 may include a display device, such as a cathode ray tube (CRT) or liquid crystal display (LCD) monitor, for displaying information to a user, a keyboard, and a pointing device, such as a mouse or a trackball, by which a user can provide input to the tree measurement system 302.

[0051] Any or all of the systems and devices described herein may be implemented using one or more computers, such as tree measurement system 302 of FIG.

[0052] Those skilled in the art will recognize that an actual computer or computer system implementation may have other structures and include other components, and that the tree measurement system 302 of FIG. 3 is a high-level representation of some of the components of such a computer for illustrative purposes.

[0053] The foregoing Detailed Description should be understood in all respects as illustrative and not restrictive, and the scope of the invention disclosed herein should be determined not from the Detailed Description, but from the claims interpreted in their entirety as permitted by each patent law. It should be understood that the embodiments shown and described herein are merely illustrative of the principles of the invention, and that various modifications may be made by those skilled in the art without departing from the scope and spirit of the invention. Those skilled in the art could implement various other feature combinations without departing from the scope and spirit of the invention.

Claims

1. A method for detecting vegetation by transmitting ultrasonic signals toward vegetation using one or more transducers that are a single device for transmitting and receiving signals; receiving, by the one or more transducers, a plurality of echo signals as reflections of the ultrasound signal; calculating a plant density of the vegetation based on the plurality of echo signals; 11. A computer-implemented method comprising:

2. receiving, by the one or more transducers, a plurality of echo signals as reflections of the ultrasound signal includes receiving the plurality of echo signals within a time window; calculating a plant density of the vegetation based on the plurality of echo signals includes calculating a plant density of the vegetation based on a quantity of the plurality of echo signals received during the time window; The computer-implemented method of claim 1 .

3. receiving, by the one or more transducers, a plurality of echo signals as reflections of the ultrasound signal includes receiving the plurality of echo signals within a time window; calculating a plant density of the vegetation based on the plurality of echo signals includes calculating a plant density of the vegetation based on intensities of the plurality of echo signals received during the time window; The computer-implemented method of claim 1 .

4. receiving, by the one or more transducers, a plurality of echo signals as reflections of the ultrasound signal includes receiving the plurality of echo signals within a time window; calculating a plant extent of the vegetation based on a first echo signal of the plurality of echo signals received during the time window and a last echo signal of the plurality of echo signals received during the time window. The computer-implemented method of claim 1 .

5. Calculating a plant extent of the vegetation based on a first echo signal of the plurality of echo signals and a last echo signal of the plurality of echo signals includes: calculating a first distance between the one or more transducers and the vegetation based on the first echo signal; calculating a second distance between the one or more transducers and the vegetation based on the final echo signal; determining the plant width as the difference between the first distance and the second distance; The computer-implemented method of claim 4 , comprising:

6. generating a map of the vegetation based on at least one of the plant extent or the plant density using global positioning system (GPS) data. The computer-implemented method of claim 4.

7. applying a substance to the vegetation in a variable amount determined substantially in real time based on at least one of the plant extent or the plant density. The computer-implemented method of claim 4.

8. Detecting a specific echo signal associated with one or more non-vegetative structures from the plurality of echo signals based on at least one of: 1) a distance determined based on the specific echo signal; or 2) an intensity of the specific echo signal; deleting the particular echo signal from the plurality of echo signals; The computer-implemented method of claim 1 , further comprising:

9. and normalizing the plurality of echo signals based on a distance between the one or more transducers and the vegetation. The computer-implemented method of claim 1 .

10. The computer-implemented method of claim 1 , wherein the one or more transducers are attached to an agricultural machine.

11. A non-transitory computer-readable storage medium storing computer program instructions that, when executed by a processor, cause the processor to perform operations; The operation is transmitting ultrasonic signals toward vegetation with one or more transducers that are a single device for transmitting and receiving signals; receiving, by the one or more transducers, a plurality of echo signals as reflections of the ultrasound signal; calculating a plant density of the vegetation based on the plurality of echo signals; 1. A non-transitory computer-readable storage medium comprising:

12. receiving, by the one or more transducers, a plurality of echo signals as reflections of the ultrasound signal includes receiving the plurality of echo signals within a time window; calculating a plant density of the vegetation based on the plurality of echo signals includes calculating a plant density of the vegetation based on a quantity of the plurality of echo signals received during the time window; The non-transitory computer-readable storage medium of claim 11.

13. receiving, by the one or more transducers, a plurality of echo signals as reflections of the ultrasound signal includes receiving the plurality of echo signals within a time window; calculating a plant density of the vegetation based on the plurality of echo signals includes calculating a plant density of the vegetation based on intensities of the plurality of echo signals received during the time window; The non-transitory computer-readable storage medium of claim 11.

14. receiving, by the one or more transducers, a plurality of echo signals as reflections of the ultrasound signal includes receiving the plurality of echo signals within a time window; the operations further include calculating a plant extent of the vegetation based on a first echo signal of the plurality of echo signals received during the time window and a last echo signal of the plurality of echo signals received during the time window. The non-transitory computer-readable storage medium of claim 11.

15. Calculating a plant extent of the vegetation based on a first echo signal of the plurality of echo signals and a last echo signal of the plurality of echo signals includes: calculating a first distance between the one or more transducers and the vegetation based on the first echo signal; calculating a second distance between the one or more transducers and the vegetation based on the final echo signal; determining the plant width as the difference between the first distance and the second distance; 15. The non-transitory computer-readable storage medium of claim 14, comprising:

16. A single device for transmitting and receiving signals, comprising: one or more transducers for transmitting ultrasonic signals toward vegetation and receiving a plurality of echo signals as reflections of the ultrasonic signals; a processor; a memory for storing computer program instructions; Equipped with The computer program instructions, when executed by the processor, cause the processor to perform an operation; the operations include calculating a plant density of the vegetation based on the plurality of echo signals; Device.

17. receiving a plurality of echo signals as reflections of the ultrasound signal includes receiving the plurality of echo signals within a time window; the operations further include calculating a plant extent of the vegetation based on a first echo signal of the plurality of echo signals received during the time window and a last echo signal of the plurality of echo signals received during the time window.

17. The apparatus of claim 16.

18. the operations further include generating a map of the vegetation based on at least one of the plant extent or the plant density using global positioning system (GPS) data.

18. The apparatus of claim 17.

19. a variable spray rate control system for applying the substance to the vegetation in a variable rate determined substantially in real time based on at least one of the plant area or the plant density; 18. The apparatus of claim 17.

20. The operation is Detecting a specific echo signal associated with one or more non-vegetative structures from the plurality of echo signals based on at least one of: 1) a distance determined based on the specific echo signal; or 2) an intensity of the specific echo signal; deleting the particular echo signal from the plurality of echo signals; 17. The apparatus of claim 16, further comprising:

21. The operations further include normalizing the plurality of echo signals based on a distance between the one or more transducers and the vegetation.

17. The apparatus of claim 16.

22. 17. The apparatus of claim 16, wherein the one or more transducers are attached to an agricultural machine.

23. A single device for transmitting and receiving signals, the device comprising: a transducer attached to an agricultural machine, the transducer transmitting an ultrasonic signal toward vegetation and receiving a plurality of echo signals as reflections of the ultrasonic signal; a tree measurement system that calculates a plant density of the vegetation based on the plurality of echo signals; Agricultural machinery equipped with

24. receiving a plurality of echo signals as reflections of the ultrasound signal includes receiving the plurality of echo signals within a time window; the tree measurement system calculates a plant extent of the vegetation based on a first echo signal of the plurality of echo signals received during the time window and a last echo signal of the plurality of echo signals received during the time window.

24. The agricultural machine according to claim 23.

25. a variable spray rate control system for applying a substance to the vegetation in a variable rate determined substantially in real time based on at least one of the plant area or the plant density; 25. The agricultural machine according to claim 24.

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