DE102008035888B4 - Device for detecting objects, such as animals and birds, in the fields and crops - Google Patents

Abstract

For the detection of objects, such as animals and bird beds, in the field and crop production, there is at least one detection device (2) oriented to the ground, which is attached to or at a predetermined distance from the front of an agricultural vehicle or is carried by a person, and one to the agricultural Data processing device assigned to the vehicle for processing signals detected by the detection device to trigger an alarm, at least one non-contact measuring distance measuring device (3) for measuring the distance between the detection device (2) and the observed floor area. Furthermore, a number of distance measuring devices (3) arranged at the same distance from one another and aligned parallel to one another can be provided for each detection device (2). Here, the distance measuring devices can be optical units, such as lasers, laser diodes, LEDs, with a small field of view and / or an optionally focusable ultrasound device with a narrow sound beam.

Description

The invention relates to a device for detecting objects such as animals and birds, in the field and crop with at least one ground-oriented detection device which at or in a predetermined distance from the front of an agricultural vehicle or at a so-called. "Infrared Wildretter" is mounted, with a data associated with the agricultural vehicle data processing device for processing detected by the detection means signals for triggering an alarm.

The use of agricultural machinery endangers animals in meadows and fields. Especially through forage harvesters for grass hay and hay silage preparation numerous kitten are injured and killed, which do not flee in case of danger, but remain motionless. Effective protection is only possible if the animals are discovered in time.

The search for juveniles, for example, by walking through the meadows, even with dogs, before the mowing, is extremely laborious and time-consuming, can be carried out only in individual cases and is unsuitable as a broad-based protection and rescue operation.

For some years, the so-called. "Infrared wild rescuer" used, which facilitates the search for fawns on foot with a large working width. The disadvantage is that the simple and inexpensive technology recognizes only temperature differences; no picture is generated. Therefore, even warm spots in a meadow can trigger false alarms, such as when the flowers of certain grasses (mainly from the genus of the foxtail grass, Alopecurus) are warmed by the sun, get close to the sensor in his field of vision and fill this to a large extent. These grasses reach stature heights between 30 cm and 150 cm. Similarly, dead leaves are often heated on the meadow floor in high sun. The false alarms therefore increase the time required for the search and make a use of mower-mounted technology impracticable. ( DE 37 30 449 C2 ; DE 100 16 688 C2 ; DE 102 58 347 B4 )

The experience of many years of practice show that the high detection reliability of these devices is therefore not 100% and again z. As fawns come under the mowing, which is considered disadvantageous.

The development of search devices based on imaging optical and infrared sensors and microwave sensors is not yet so far that they can be used on foot or on mowers.

The object of the invention is therefore to provide a device according to the preamble of claim 1, with the detection reliability is further increased in the search for juveniles, especially fawns and Bodenbrütergelegen in meadows. This object is achieved in a device according to the preamble of claim 1 with the features in its characterizing part. Advantageous developments are the subject of dependent claims.

With the device according to the invention, further facts are recorded and used for the combined evaluation with the data stored in a computer or microprocessor. The device according to the invention can also be used independently for Kitzsuche. However, an increase in the detection reliability is achieved especially when using the device according to the invention in combination with other methods or devices.

At sites where fawns, hunts or bird cuddles are or have been found in meadows, the grass is depressed or the growth of grass is suppressed. Outside a deposit, the grass to be mowed already has a height of at least 30 cm or more; it can be up to 1 m or higher. This is used by a distance measurement by means of a distance measuring device, which is carried out in parallel to one or more detection measurements carried out by means of detection devices.

Detection measurements mostly detection sensors are used, either vertically down to the ground aligned, optically imaging systems such as video camera, infrared camera u. Ä., or non-imaging optical systems, such as infrared sensors, which are provided for example in the above-mentioned portable infrared wildlife rescuers. Detection sensors mounted on a support device are passed over the meadow at a certain height, usually over the longest blades of grass.

First, a preferred combination with optical detection sensors will be described. Parallel to each of these sensors, as close as possible to, or in unit with, these, at least one non-contact distance meter is installed to continuously measure the distance between the detection sensor (s) and the observed ground portion. As will be explained in more detail below, further distance measuring devices are equidistant on a carrying device in the case of the detection sensor (s) attached, which measure the distance to the meadow floor or grass.

Each distance measuring device is preferably an optical device with a small field of view angle, or else an optionally narrowable sonic device with a narrow sound beam. The visual field angle of the optical distance meter, such as laser, laser diode, LED is so narrow that with a distance measurement of usually 120 to 150 cm after individual grass leaves / halms are detected.

In operation, by means of each distance sensor, a distance profile is recorded along its trajectory, recorded digitally and evaluated in parallel with the other stored and / or recorded data. The recording first takes place as a diagram of the distance over time. About the parallel and simultaneous running measurement and recording the speed of movement of a carrier, such as a mowing vehicle or a person carrying the searcher, the time is converted into the place and the profile as a distance above the vehicle path (possibly with GPS support also on the place in Terrain). The speed of movement of the person wearing the device is measured by means of a known speed / acceleration sensor system which is integrated into the system and transmits the movement data (speed, direction) to the evaluation systems (computer, microprocessor).

The following features are used for the evaluation:
By moving the distance measuring devices at a constant height over a homogeneous piece of meadow a profile is recorded, which reflects a distributed according to the vegetation height and type of change between maximum distance (meadow floor) and smallest distance (tips of grass blades) and intervening intervals. From the profiles, which were measured in undisturbed meadow, the distance to the meadow floor is determined as the repeated and very frequently occurring, largest measured distance.

For example, if there is only a Kitzlager in the detected meadow piece, so this is recognizable in the profile as a section with constant greatest distance (meadow floor). The detection of a Kitzlagers without fawn is also helpful, because it can be assumed, where a Kitzlager is, is usually also a fawn in the vicinity to find.

If there is a fawn in the camp, the distance in this section is about the body height (10 to 15 cm) of a lying Fawn lower. Thus, the impact first rises from the edge of the carcass body, follows the body and drops off again to the meadow floor (Kitzprofile). Since the distance to the meadow floor from the immediately preceding measurements is known, it is thus detected by comparing the distances, whether a fawn is in the camp or not.

The size of the section with constant maximum distance, if no fawn is in the camp, or the size of the section with Kitzprofil (maximum distance to maximum distance minus 20 cm) corresponds to the diameter of a typical (approximately circular) Kitzlagers, if the trajectory and measuring beam central goes over the camp; If they run more at the edge, the distance (secant) is shorter. The actual size can be determined using the time synchronously measured and recorded movement speed. Kitzlager are also registered for scientific mapping; however, no alarm is triggered, but a hint is signaled.

For safe detection of a faeces, the distance sensors are preferably mounted in sufficient number and density on the carrying device (for example at a distance of about 10 cm), that on the one hand a complete local congruence is achieved by means of the detection sensors and on the other hand in each case at least two, better three until four distance sensors detect an existing fawn.

Correlate time and place of the distance profile referring to a fawn in the Kitzlager (distance: meadow ground plus Kitzkörper, relative course: "Kitzprofil") with the signal "temperature jump" or "Fawn found" of the optical detection sensor, an alarm is triggered.

Does the optical detection sensor the signal "temperature jump" or "fawn found" and the distance sensors for the place (the time) an unsuitable distance profile (constant distance to the meadow floor, or not constant, a change with typical frequency and amplitude, as short previously detected), so no alarm is triggered.

Areas in the meadow in which the grass is pressed by the influence of rain / storm to the ground, are usually large-scale and are therefore recognized by means of the distance measurement as such. Here are usually no fawns / young rabbits. Relative and absolute profit show no resemblance to a fawn profile.

A distance meter has a height resolution in the range of millimeters. For detecting animals in the field or plant ground, an absolute accuracy of the distance measurement in the range of about one centimeter is sufficient. The spatial resolution (measuring spot) is preferably in the range 1 to 2 mm, so that individual blades of grass and grass blades are detected. The predominant part of the measurement object, the meadow, is very "rough" and is characterized by spatially occurring, very large height differences (closely growing, long grasses). At a movement speed of about 5 km / h, which is about 1.40 m / s (pedestrian) or up to 20 km / h, which corresponds to 5.4 m / s (mower), the device is about 1400 mm or 5400 mm in one second moves relative to the ground. To avoid "smearing" in the direction of movement, the measuring rate is about 0.5 to 2.5 kHz.

In combination with microwave detection sensors, the device according to the invention is used in a comparable arrangement. If an optical distance meter is used, it must be aligned vertically downwards to the meadow floor, while the microwave sensor must "look ahead" in advance. When both are mounted on the support at approximately the same location with respect to the direction of travel of the agricultural vehicle, then the two types of sensors monitor each location in temporal succession, first the microwave sensor and then the distance sensor.

The temporal offset of the two observations depends on the mounting height of the microwave sensor and the inclination of its optical axis against the solder on the ground. In the data evaluation these conditions, namely the measured and recorded speed of the moving sensors, are taken into account.

The simultaneity of both measurements can be achieved by mounting both sensors one behind the other on the support device in the direction of movement so that both simultaneously observe the same area on the ground. The distance sensor is mounted in the direction of movement of the agricultural vehicle in front of the microwave detection sensor, which measures inclined in the direction of movement forward.

Thus, the mounting distance between the two sensors for a predetermined mounting height above the bath results from the above-mentioned observation geometry of the microwave sensor, in which thus the measurement and consideration of the movement speed can be omitted. The simultaneity of observation requires compliance with the constant mounting height of the sensors with respect to the ground, which is optionally achieved by an active position stabilization of the support device.

• 1.) Eigenständige Abstandsmesser parallel zur Detektionssensorik, wie beispielsweise optische Triangulation, optische Laufzeitmessung, Ultraschall-Messung von Laufzeit und Intensität des Echos
• 2.) Kombinierte Detektion und Abstandsmessung in bevorzugter Ausführungsform: Abbildende Detektionssensoren (Videokamera, IR-Kameras) werden in Stereoanordnung/ausführung verwendet. Bekannte Bilddatenverarbeitung ermöglicht eine Abstandsbestimmung aus Stereobildpaaren.

A distance measurement can be done in different ways:

• 1.) Stand-alone distance meter parallel to the detection sensor, such as optical triangulation, optical transit time measurement, ultrasonic measurement of transit time and intensity of the echo
• 2.) Combined detection and distance measurement in a preferred embodiment: Imaging detection sensors (video camera, IR cameras) are used in stereo arrangement / execution. Known image data processing allows distance determination from stereo image pairs.

The invention will be explained in more detail with reference to the drawings. Show it:

1 a schematic representation of a preferred modular embodiment;

2 a schematic representation of the combination of several modules;

3 a height profile of grass and empty Kitzlager, and

4 a height profile of grass and camp with fawn.

1 schematically shows a sensor module 1 having an unspecified electronic control and signal processing unit, and to which a detection sensor 2 and five distance sensors 3 are mounted. The detection sensor 2 has a schematically represented visual field angle, represented by two marginal rays 2a and adapted to the respective mounting height, is dimensioned so that a bottom element of about the size of a resting fawn with a diameter of about 40 to 50 cm, is detected.

The detection sensor 2 are in 1 five optical distance sensors 3 each assigned their very narrow beam through a fine optical measuring beam 3a are shown schematically. The five distance sensors 3 are equidistantly mounted with respect to the signal processing unit not shown in such a way that they are one from the detection sensor 2 detected (not shown) bottom element symmetrical to the optical axis of the detection sensor 2 capture, a distance meter 3 on the optical axis of the detection sensor 2 and two distance meters each 3 right and left of it. The distance between the two distance sensors is for example 10 cm, or a few centimeters more or less.

The optical axes of all distance sensors 3 are parallel to each other and to the optical axis of the detection sensor 2 (the central ray of field of view angle). The electronic Control and signal processing unit is connected to a central data acquisition and data evaluation unit, which as well as a unit for alarming in 1 not shown.

2 schematically shows the coupling of three sensor modules 1 to 1 which cover a strip of about 150 cm in width and which are mounted on a support structure, not shown, which serves for attachment to the mowing vehicle, or for carrying in a search on foot. The modules are sized so that there is little overlap of that from the detection sensors 2 detected ground elements and an equidistance of all distance sensors is given. All optical axes are parallel to each other. The modules 1 are mounted on the mowing vehicle so that all optical axes are aligned perpendicular to the ground.

During forward movement of the sensor, because of the shaking movements of the vehicle or the carrier and the "roughness" of the meadow, in the case of distance measurement, the optical measuring beam of the distance sensor is not reflected only from a point (blade of grass, ground). The beam can be split; the parts of different stalks, or of stalks and ground can be reflected. It can also lead to multiple reflections, since the stalks are dense and oriented only in exceptional cases perpendicular to the beam direction.

A distance measurement, based on the propagation time measurement of the optical measurement signal, will also provide a clear result under these circumstances, since the first reflected signal determines the measurement, which is usually the strongest. Travel time measuring distance sensors can not be used below a given shortest distance between sensor and object. For example, this shortest distance can be 20 cm. The mounting or support height, adjusted accordingly, is thus at least 20 cm above the longest grasses / plants.

A distance measurement based on triangulation can lead to ambiguous results under the conditions described above. The distance sensor for triangulation is therefore designed according to the invention so that several distances can be measured simultaneously. In such a case, this is regarded as an additional indication that the surface is highly structured, ie meadow.

If animals other than fawns or eggs are to be searched for by soil breeders, the sensors are adapted to the corresponding geometrical conditions. The data analysis also takes this into account. In particular, for example, the absolute height resolution will possibly be in the range of millimeters, for example. The distance between the distance sensors can be in the range of a few centimeters. Also the clutch size, Eldimensionen u. Ä. In the evaluation observed.

In particular, in the search for small animals and opportunities stereo cameras (infrared and / or video camera) are provided with a geometric resolution in the lower millimeter range, so that even small birds eggs are recognized according to a preferred embodiment.

The distance sensor continuously measures the height profile of the meadow and detects whether standing or lying grass, or a camp with or without Kitz located in the field of view of the detection sensor. The number of misinterpretations of the signals of the detection sensor is thereby greatly reduced.

With the distance meter provided according to the invention, a height profile of the soil, the vegetation and the objects located on the ground is determined. Geometric reference obtained at the beginning of the mission (reference altitude) is the distance to a flat, non-overgrown ground surface in the operational operation of the sensor system. For this purpose, for example, the sensor system is not moved, but held in peace in its operating position. (The agricultural machine is standing, the carrying person is in search position). In this condition, distance measurements are made to the (unvegetated) soil. The measured distance is stored as a reference distance.

Alternatively, the vehicle can drive slowly to this measurement even on a level surface, in particular, a shaking and vibration of the sensors is to be avoided. Ideally, the distance meter retains its position during subsequent operation, i. H. the distance to the reference surface. In reality, the sensor system with the distance meter may be exposed to movements perpendicular to the ground during operation. These movements lead to changes in the distance with respect to the reference surface and contribute to the distance measurement. So they distort the measured soil / vegetation profile by the superimposed distance changes, which changes the distance to the reference.

• 1a) Des Abstandsmessgerät wird von einer Person in der Regel mittels eines Schultergurts getragen, und hängt vor der Brust/dem Bauch. Des Gehen führt zu periodischen Auf- und Abwärtsbewegungen der Schultern, die mit der Schrittfolge korrelieren, wenige Zentimeter betragen und auch vom Sensorsystem mitgemacht werden, wodurch sich der Abstand zum Boden periodisch ändert.
• 1b) Des getragene Gerät weist in der Regel ein Gestänge auf, das auf beiden Seiten des Schultergurts einige Meter vorsteht und an dem mehrere Einzelsensoren äquidistant montiert sind. Die Gehbewegungen induzieren eine mit der Schrittbewegung korrelierte, periodische Schwingung des Gestänges senkrecht zum Boden. Die Amplitude der Schwingung ist an den freien Enden des Gestänges am größten, an der Gurtaufhängung am kleinsten. Die Sensoren sind den Schwingungen natürlich auch ausgesetzt. Die Einzelsensoren ändern dadurch ihren Abstand zum Boden synchron zur Schwingung mit unterschiedlichen Amplituden, die von der Lage am Gestänge abhängen, d. h. sie sind groß an den freien Enden und klein am Gurt.
• 2a) Ist des System an einer Landmaschine montiert, so erfolgt dies in der Regel mittels einer mechanischen Halterung, beispielsweise in Form eines über den abzusuchenden Streifen hinaus ragenden Gestänges. Landmaschinen und Sensoren sind Bewegungen senkrecht zum Boden augesetzt, die durch Bodenunebenheiten und Fahrbewegungen (Nicken, seitliche Neigung) hervorgerufen werden. Dies führt zu Abstandsänderungen der Sensoren in Bezug auf den Boden. Der Betrag (die Amplitude) der Abstandsänderung hängt von der Lage/Position des Abstandssensors am Fahrzeug, bzw. Gestänge ab. Auch hier treten darüber hinaus gegebenenfalls Schwingungen des Gestänges auf, die zu Abstandsänderungen führen.
• 2b) Laufende Motoren und Werkzeuge der Landmaschine erzeugen mechanische Vibrationen, die sich auf das gesamte Fahrzeug übertrage. Sie übertragen sich auch auf die Sensoren, wenn diese starr mit der Fahrzeugstruktur gekoppelt sind. Diese Vibrationen können Abstandänderungen der Sensoren zum Boden bewirken, die im Betrieb in der Regel kleine Amplituden (im Millimeterbereich) und mittlere Frequenzen (einige Hertz bis einige hundert Hertz) haben.

The disturbing influence happens in different ways:

• 1a) The distance measuring device is worn by a person usually by means of a shoulder strap, and hangs in front of the chest / stomach. Walking leads to periodic up and down movements of the shoulders, which correlate with the sequence of steps, amounting to a few centimeters and also be followed by the sensor system, whereby the distance to the ground changes periodically.
• 1b) The worn device usually has a linkage which protrudes a few meters on both sides of the shoulder strap and on which a plurality of individual sensors are mounted equidistantly. The walking movements induce a periodic oscillation of the linkage perpendicular to the ground, correlated with the step motion. The amplitude of the oscillation is greatest at the free ends of the linkage, smallest at the belt suspension. Of course, the sensors are also exposed to the vibrations. The individual sensors thereby change their distance to the ground in synchronism with the vibration with different amplitudes, which depend on the location on the linkage, ie they are large at the free ends and small on the belt.
• 2a) If the system is mounted on an agricultural machine, this is usually done by means of a mechanical support, for example in the form of a protruding beyond the strip to be searched out rod. Agricultural machinery and sensors are subjected to movements perpendicular to the ground, caused by uneven ground and driving movements (pitching, lateral inclination). This leads to changes in the distance of the sensors with respect to the ground. The amount (amplitude) of the change in distance depends on the position / position of the distance sensor on the vehicle or linkage. Here, too, possibly occur on vibrations of the linkage, which lead to changes in distance.
• 2b) Running engines and tools of the agricultural machine generate mechanical vibrations that are transmitted to the entire vehicle. They also transfer to the sensors when they are rigidly coupled to the vehicle structure. These vibrations can cause distance changes of the sensors to the ground, which in operation usually have small amplitudes (in the millimeter range) and medium frequencies (a few hertz to a few hundred hertz).

• a) ungestörte Vegetation
• b) Lager mit Kitz (3)
• c) Lager ohne Kitz (4)
• d) Größe eines Lagers oder einer Stelle mit niedergedrückter Vegetation.

The described movements and the resulting changes in distance are only disturbing for the task, if they prevent the distinction of the four essential characteristics:

• a) undisturbed vegetation
• b) Bearings with Fawn ( 3 )
• c) camp without fawn ( 4 )
• d) Size of a warehouse or a place with depressed vegetation.

• – einerseits fehlerhaft als vorhanden angesehen wird, obwohl nicht vorhanden, und
• – andererseits fehlerhaft unterdrückt wird, obwohl vorhanden.

Essentially, it must be prevented that feature b)

• - on the one hand is considered erroneous as available, though not present, and
• - On the other hand, erroneously suppressed, although present.

In this regard, the measures explained below are taken to avoid, compensate or correct the disturbing changes in distance. It always includes the information provided by the detection sensor:
To 1a) and 1b): The wearer is trained to carry the sensor linkage quietly and to avoid vertical movements. By means of low-pass filtering, the low-frequency components (corresponding to the low-frequency periodic distance changes) are also extracted from the signals of each distance sensor and compared with respect to frequency, amplitude and phase. For example, for a sensor (or one to three or four adjacent sensors) feature b) is detected, which in the waveform of the principle in 4 corresponds, it is checked whether the low-frequency components of the signals of the other distance sensors (in particular the immediately adjacent) have a correlated phase and amplitude and frequency course. If this is the case and if the detection sensor delivers the knowledge "no fawn" at this point (characteristic b), then characteristic b) is regarded as a false alarm.

Similarly, the signals and the low-pass filtered signals from the proximity sensors and the signals from the detection sensors are compared and inferred, and decisions and measures taken.

To 2a) and 2b): The sensor mounts are mounted on the vehicle / linkage so that the vibrations of the vehicle structure are transmitted as little as possible to the sensors and negligible distance changes in the range of millimeters can be treated as noise. For this purpose, known methods and assembly techniques are used (shockmounts). For example, vehicle movements of greater amplitude, such as pitch, lateral tilt, are treated like the low frequency motion changes of FIGS. 1a) and 1b).

In another embodiment, accelerometers are used which are mounted on one or more sensors, which participate in movements of the sensors and provide information about the movements. Here, too, the signals and measured values of the distance sensors, the detection sensors and the accelerometers are evaluated accordingly and conclusions drawn, decisions taken and measures taken.

In a further embodiment, the measurement signals of the distance sensors are low-pass filtered. Bandwidth and cut-off frequencies are adapted to the speed of movement of the sensors and the size of the fawn in such a way that the (low-frequency) signal curves resulting from overlapping faults are transmitted, but all others are suppressed. By comparing the low-pass filtered signals of all distance sensors the above-mentioned disturbing distance changes that generate similar waveforms as stored Kitze, recognized and thus confirmed the clearly caused by overlapping Kitze waveforms. Depending on the result, alarm is triggered or not.

Claims (6)

Device for detecting objects, such as animals and birds, in the field and crop with at least one ground-oriented detection device, which is attached to or at a predetermined distance from the front of an agricultural vehicle or carried by a person, with an agricultural vehicle associated Data processing device for processing signals detected by the detection device for triggering an alarm, characterized in that the detection device ( 2 ) at least one non-contact distance measuring device ( 3 ) for measuring the distance between the detection device ( 2 ) and the observed ground area, wherein with the at least one distance measuring device ( 3 ) an altitude profile of soil, vegetation and on the ground befindlicher objects is determinable. Device according to claim 1, characterized in that in each detection device ( 2 ) a number of equally spaced apart and parallel aligned distance measuring devices ( 3 ) is provided. Device according to claim 1 or 2, characterized in that each distance measuring device is an optical unit (laser, laser diode, LED) with a small field of view. Device according to one of claims 1 or 2, characterized in that each distance measuring device is an optionally focusable ultrasound device with a narrow sound cone. Device according to one of claims 1 or 2, characterized in that a stereo camera or in the visible range a stereo video camera is provided as a distance measuring device in the infrared range. Device according to claim 1, characterized in that the data processing device is associated with a low-pass filter for filtering the output from the distance measuring instruments measured signals.

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