FR3078774A3 - DEVICE AND METHOD FOR MEASURING PLANT COVER HEIGHT - Google Patents

Abstract

The invention relates to a device and an associated method for measuring the height of vegetation cover. The device (2) comprises a portable support device (8), a measurement acquisition device (16) comprising an ultrasonic sensor (18) fixed to said support device (8), a programmable microprocessor (22) and a card memory (24), the memory card being adapted to store acquired height measurements. It also comprises a control device (30), comprising a man-machine interface (32), the control device (30) being adapted to control the acquisition device (16) and to receive transmitted height measurement results. by the measurement acquisition device. This portable support device (8) comprises a first support arm (10) and a second support arm (12) perpendicular to the first support arm (10), the acquisition device (16) being fixed on the second arm support (12) so that the ultrasonic sensor (18) is adapted to emit ultrasound (19) above said vegetation cover to be measured.

Description

Device and method for measuring the height of vegetation cover

The present invention relates to a device for measuring the height of vegetation cover and a method for measuring the height of the associated plant cover. The invention lies in the field of plant cover height measurement.

It finds applications in agronomic research and crop monitoring in general.

In particular, it is useful to regularly record plant cover heights on experimental plots, in order to follow the development of plants over a period of observation.

A simple and known method is to perform a manual survey using a height measuring instrument, for example a pole or a ruler. The completion of a survey is quite tedious, because if only one person makes the measurements, it must take the measurement and then take note. In general, teams of two are planned to perform this task.

U.S. Patent 8,370,075 discloses a portable plant structure height measurement system, which includes a camera that is carried by a support pole, adapted to capture photos of the observed plants in a substantially vertical plane. In more sophisticated embodiments several other sensors are added, among which an ultrasonic sensor used to determine the height measurement system height including the camera, replacing a graduation of the boom. The system of this patent is in particular used for corn analysis. For a determination of height measurement, the user must maintain the vertical boom and change the height of the camera by visually monitoring the image taken by the camera until alignment with the maximum height of the observed structure. This is a process that requires positioning accuracy and several camera height adjustments, which seems tedious.

The purpose of the device of the invention is to propose a device for measuring height of plant cover with improved ergonomics, and which reduces the effort to be provided by the user. For this purpose, the invention proposes a device for measuring the height of vegetation cover comprising a portable support device, a device for acquiring measurements and a device for controlling the device for acquiring measurements. The measurement acquisition device comprises an ultrasonic sensor, a programmable microprocessor and a memory card, the memory card being adapted to store acquired height measurements. The control device comprises a man-machine interface, the control device being adapted to control the measurement acquisition device and to receive height measurement results transmitted by the measurement acquisition device, the portable support device having a first support arm, and a second support arm perpendicular to the first support arm, the acquisition device being attached to the second support arm so that the ultrasonic sensor is adapted to emit ultrasound above of said vegetation cover to be measured.

Advantageously, the plant height measurement device of the invention makes it possible to obtain and record measurements ergonomically, thanks to the human-machine interface of the control device.

The plant cover height measuring device according to the invention may have one or more of the characteristics below.

The first support arm is formed of at least two nested portions so as to be adjustable in height.

The control device is attached to said first support arm, fixedly or by a translationally sliding connection.

The measurement acquisition device and the control device are connected by a wire connection.

The measurement acquisition device and the control device each comprise a wireless communication module and are adapted to communicate by a wireless communication protocol. The human-machine interface includes user-operable control buttons adapted to control a calibration height measurement, a canopy height measurement, a recording and / or erasure of measurements. The human-machine interface has a touch screen display.

The ultrasonic sensor comprises an ultrasonic emission axis, the device further comprising a rod of transparent material, fixed perpendicularly slidingly in translation to the first support arm and adapted to be positioned in line with the axis of ultrasound emission.

According to another aspect, the invention relates to a method of measuring plant cover height by a plant cover height measuring device as briefly described above, comprising steps of: -receiving an acquisition command measuring the height of the canopy, emitting at least one ultrasonic beam above the canopy to be measured by an ultrasonic sensor and obtaining a measurement of the distance between the canopy and an emission surface / reception of said sensor, -calculus of a height of vegetation cover as a function of the distance measurement or measurements obtained and a previously acquired calibration measurement.

This method comprises, in one embodiment, a prior step of acquiring a calibration measurement by emitting at least one ultrasonic beam over a zone devoid of vegetation.

This method comprises, in one embodiment, the acquisition of a number N greater than one of distance measurements between the canopy and a transmission / reception surface of said sensor, and the calculation of an average value of said measurements. . Other characteristics and advantages of the invention will emerge from the description given below, by way of indication and in no way limiting, with reference to the appended figures, among which: FIG. 1 is a schematic representation of a device plant cover height measurement according to a first embodiment of the invention; FIG. 2 is a schematic representation of a plant cover height measuring device according to a second embodiment of the invention; FIG. 3 is a schematic representation of a plant cover height measuring device according to a third embodiment of the invention.

Figure 1 shows schematically a device 2 for measuring the height of vegetation cover according to a first embodiment of the invention.

Vegetation cover is the highest part of a group of plants covering the ground. For example, in one use of the invention, it is a set of plants grown on a plot.

Plants 4 are shown schematically in Figure 1, on a floor 7.

Of course, the device of the invention is suitable for measuring the height of plant cover for various types of plants, for example peas, maize, rapeseed, wheat, the device 2 being suitable for height measurements of plant cover between 10 cm. and 3 meters from the ground.

The plant cover height measuring device 2 comprises a support device 8 composed of a first support arm 10 and a second support arm 12, the second support arm 12 being fastened substantially perpendicularly to the first support arm 10.

The measuring device 2 is portable, easy to move from a first place to a second place, because its weight is limited.

For a measurement, the support device 8 is for example maintained in a static position by hand by a user (not shown).

Alternatively, the support device 8 is held in a static position by a stabilizing device 14, which for example has feet 15a, 15b forming a base.

In the embodiment shown, the first support arm 10 is formed of two nested portions, a first portion 10a and a second portion 10b, the first portion 10a having a diameter greater than the diameter of the second portion 10b. The second support arm 12 is fixed to the second part 10b.

Thus, the first support arm is telescopic, adjustable height, which makes the measuring device more ergonomic, easier to wear and adaptable for measurements compared to plant covers of varying height.

According to a variant not shown, the first support arm has a number greater than two nested parts, which further improve its adaptability compared to a height adjustment.

According to one embodiment, the first support arm 10 has graduations visible on the surface, allowing the user to read the height Z of the second support arm.

The support device 8 is adapted to carry a measurement acquisition device 16.

The measurement acquisition device 16 comprises an ultrasonic sensor 18, placed in a housing 20. The sensor 18 is adapted to emit an ultrasound beam 19 at a given frequency, for example at 40 kHz, and to pick up ultrasound at the same frequency.

The beam 19 scans an area of given diameter. Advantageously, a commercially available ultrasonic sensor can be used.

For example, a Grove ® SEN10737P type sensor, operating at an ultrasound emission frequency of 40 kHz, and having a range of between 3 cm and 400 cm can be used.

Preferably, the first support arm 10 is adjusted so that the sensor 18 is placed between 30 cm and 1 m above the plant cover whose height is to be measured.

The ultrasonic sensor 18 is itself placed at a height X with respect to the ground.

The ultrasonic sensor 18, following the emission of an ultrasound beam 19 and the reception of reflected waves is adapted to accurately measure the distance Y between the plant cover to the right of which it is positioned and the surface of the transmission / reception, materialized in the figure by the lower wall of the housing.

The precise measurement of the distance Y makes it possible to calculate the height H of the vegetal cover.

Indeed, according to a first embodiment, during a calibration phase the measurement acquisition device 16 is controlled to emit ultrasound towards the ground, in a zone without vegetation, which makes it possible to measure the height X The value of the height X with respect to the ground is memorized.

In known manner, it is possible to calculate a distance d by such a sensor, for example in centimeters, as a function of the velocity C of the waves emitted by the ultrasonic sensor and the time elapsed between a moment of emission and a moment of receiving wave reflected on the obstacle encountered by the formula: d = (C x dT) / 2, where 'x' represents the multiplication.

The measured distance can be fine-tuned according to the sensor.

The vegetation cover height H is then calculated simply by the difference between X and Y.

According to an alternative embodiment, when the first support arm 10 is graduated, it is possible to read the height Z relative to the ground. Since the dimensions of the housing 20 are known, the height X with respect to the ground can be deduced from it, and then the height of vegetation cover is calculated as a function of the height X and the distance Y measured using the ultrasonic sensor 18, as explained above.

The acquisition device comprises a programmable microprocessor 22 adapted to perform calculations when it is powered up, and a memory card 24.

For example, an ARDUINO® type microprocessor is used.

In the embodiment of FIG. 1, the measurement acquisition device 16 is connected by a wire link 26 to a control device 30.

For example, the wired link 26 is a USB ("Universal Serial Bus") cable for transmitting data.

The control device 30 is attached to the first support arm 10 by a connection 28 fixed or sliding in translation so as to adjust the height. Preferably, the control device is positioned at an ergonomic height for the user, to allow repeated handling without fatigue.

The control device 30 comprises a man-machine interface 32, for example a liquid crystal display, as well as control buttons 34.

The user-actuable control buttons 34 are adapted to control a calibration height measurement, a canopy height measurement, a recording and / or erasure of height measurements.

In one embodiment the screen 32 is a touch screen and the control buttons are displayed on the screen and are selected by the user.

The commands are transmitted to the acquisition device 16 via the wire link 26.

The control device also comprises a power supply module 36, for example a 9V battery.

Thus, the control device is autonomous.

The acquisition device 16 is also electrically powered by the power supply module 36, via the wire link 26.

In addition optional, at least some of the control buttons are provided with a buzzer / buzzer (which is called "buzzer" in English), which increases the ergonomics of the device. For example, a first warning frequency is used for a measurement enable, and a second warning frequency, for example more severe, is used when the user requests an erase or correction of the height measurement.

FIG. 2 diagrammatically represents a device 2 'for measuring the height of vegetation cover according to a second embodiment of the invention.

The common parts with Figure 1 retain the same reference numbers. Unlike the first embodiment, in this embodiment the measurement acquisition device 40 further comprises a power supply module 42 and a wireless communication module 50.

Preferably, the module 50 is adapted to communicate according to the Bluetooth ® communication protocol.

The control device 52 is in this communication mode adapted to communicate according to the wireless communication protocol mentioned above with the acquisition device 40. For this purpose, the control device 52 comprises a wireless communication module 54 .

In one embodiment, the controller 52 is for example a touch pad, or a laptop or smartphone that implements code instructions to control the measurement acquisition device 40 and to receive and store data from the device. received.

The control device 52 also comprises a man-machine interface 56, control buttons 55 of the measurement acquisition device 40, for example displayed on the man-machine interface 56. It also comprises a microprocessor 58 and a control unit. electronic memory 60, as well as a power supply module 62.

In addition optional, as explained with reference to Figure 1, at least some of the control buttons 55 are provided with a buzzer / buzzer, which increases the ergonomics of the device.

Figure 3 schematically illustrates a device 2 "for measuring the height of vegetation cover according to a third embodiment of the invention.

In this third embodiment, the measuring device 2 "comprises elements of the first embodiment, but it also comprises a rod 64 of material adapted to reflect the waves emitted by the ultrasonic sensor, preferably transparent, for example in Plexiglas ®. The rod 64 is fixed perpendicularly and slidably in translation to the first support arm 10, and vis-à-vis the emission zone of the ultrasonic sensor 18, so that the waves emitted by the sensor to ultrasound pass through said rod 64.

In this embodiment, the first support arm 10 has for example a fixed height, and the second support arm 12 is fixed at a predetermined maximum height.

Advantageously, the rod 64 makes it possible to improve the reflection of the waves emitted by the ultrasonic sensor.

Advantageously, the height of the rod 64 is adjustable.

Thus, in the calibration phase, the rod 64 is positioned flush with the ground, which makes it possible to measure the height X.

In the measurement phase the user can adjust the height of the rod 64 so as to position it at the highest point of the canopy to be measured, as shown in FIG.

In one embodiment, a groove device on the housing 20 and on the rod 64 makes it possible to position the rod 64 with respect to the emission axis A of the ultrasonic sensor 18, so that the rod is positioned to the right of beam 19 emitted.

According to a fourth embodiment not shown, a strip of reflective material, preferably transparent, analog is added to the measuring device 2 'described with reference to Figure 2.

The measuring device 2, 2 ', 2 "of the invention is adapted to implement a method of measuring height of plant cover according to the invention.

The method is implemented by the execution of software instructions by the processors 22, and 58 as appropriate, depending on the user commands acquired via the man-machine interface 32, 56 and the controller. activation of the control buttons 34, 55.

The method comprises an initial step of calibrating the height X with respect to the ground, following the reception of a calibration command.

Then the method comprises receiving a height measurement acquisition command.

The command is transmitted to the ultrasonic sensor 18 which measures the height Y relative to the crown point of the canopy placed below the sensor, in the emitted beam.

The height of vegetation cover H is then calculated by taking the difference between X and Y, and stored.

Preferably, the measurement record is time stamped, and the measured vegetation cover height is stored in connection with the timestamp information.

In one embodiment, to consolidate the measurement, following a height acquisition command, the sensor is actuated an N number of times, and Y1, Y2 ... YN measurements are obtained. The stored vegetation height measurement is, in one embodiment, the average of the values Y1 to YN acquired. For example, N = 3.

In one embodiment, a field trip is proposed, each parcel of land having an associated identifier.

In this embodiment, on user command, the vegetation height measurement is stored in association with the parcel identifier and the time stamp information.

It is then possible to recover all the stored data, for example in a spreadsheet format, which facilitates their subsequent operation.

It is clear from the embodiments of the invention described that the invention makes it possible to measure plant cover height in a simplified and ergonomic way, faster than by known methods and without fatigue of the user.

Claims (11)

1. - Plant cover height measurement device (2, 2 ', 2 ") comprising a portable support device, a measurement acquisition device and a control device of the measurement acquisition device, characterized in that that the measurement acquisition device (16, 40) comprises an ultrasonic sensor (18), a programmable microprocessor and a memory card, the memory card being adapted to store acquired height measurements, the control device (30, 52) comprises a man-machine interface, the control device being adapted to control the measurement acquisition device and to receive height measurement results transmitted by the measurement acquisition device, the portable support device (8). ) having a first support arm (10) and a second support arm (12) perpendicular to the first support arm, the measurement acquisition device (16, 40) being attached to the second support arm s (12) so that the ultrasonic sensor (18) is adapted to emit ultrasound above said vegetation cover to be measured. 2. - Device according to claim 1, wherein the first support arm (10) is formed of at least two nested portions so as to be adjustable in height. 3. - Device according to one of claims 1 or 2, wherein the control device (30) is attached to said first support arm (10), fixedly or by a translationally sliding connection. 4. - Device according to one of claims 1 to 3, wherein the measurement acquisition device (16) and the control device (30) are connected by a wire connection (26). 5. - Device according to one of claims 1 to 3, wherein the measurement acquisition device (40) and the control device (52) each comprise a wireless communication module (50, 54) and are adapted to communicate through a wireless communication protocol. 6. - Device according to one of claims 1 to 5, wherein said man-machine interface comprises control buttons (34, 55), operable by a user, adapted to control a calibration height measurement, a measurement of vegetative cover height, recording and / or erasure of measurements. 7. - Device according to one of claims 1 to 6, wherein said man-machine interface comprises a touch screen display. 8. - Device according to one of claims 1 to 7, wherein the ultrasonic sensor (18) comprises an ultrasound emission axis, the device further comprising a rod of transparent material (64), fixed perpendicularly of slidably in translation to the first support arm (10) and adapted to be positioned in line with the ultrasonic emission axis. 9. - A method of measuring height of vegetation cover by a device for measuring the height of vegetation cover according to one of claims 1 to 8, characterized in that it comprises steps of: -receiving a control d acquisition of plant cover height measurement, emission of at least one ultrasound beam above the vegetation cover to be measured by an ultrasonic sensor and obtaining a distance measurement between the canopy and a surface of transmitting / receiving said sensor, calculating a height of vegetation cover as a function of the distance measurement or measurements obtained and a previously acquired calibration measurement. 10. - Method according to claim 9, comprising a prior step of acquiring a calibration measurement by emitting at least one ultrasound beam over a zone devoid of vegetation. 11. - Method according to one of claims 9 or 10, comprising the acquisition of a number N greater than one distance measurements between the canopy and a surface of transmission / reception of said sensor, and the calculation of an average value of said measurements.