DE102016122334A1 - Optical measuring device for monitoring and detecting objects in a surveillance area - Google Patents

Abstract

The invention relates to an optical measuring device for monitoring and detecting objects in a surveillance area, comprising at least one transmitting unit for emitting light pulses into the surveillance area, the transmitting unit having a rotatable deflection unit for sweeping the surveillance area, in particular at least in one plane, with a measuring beam. with a receiving unit for detecting light pulses reflected by objects to be detected in the surveillance area and with a control and evaluation unit for controlling the transmitting unit, for evaluating the light pulses detected by the receiving unit and for determining a position of detected objects in the surveillance area on the basis of a runtime of detected Light pulses and an angle at which the light pulses were emitted. The optical measuring device according to the invention is characterized in that the receiving unit is stationarily positioned and that an acceptance angle of the receiving unit is so large and the receiving unit is positioned so far away from the monitoring area, that reflected light pulses from the entire monitoring area of the receiving unit can be received.

Description

The present invention relates to an optical measuring device for monitoring and detecting objects in a surveillance area according to the preamble of claim 1.

A generic optical measuring device has the following components: at least one transmitting unit for emitting light pulses in the monitoring area, wherein the transmitting unit comprises a rotatable deflection unit for sweeping the monitoring area, in particular at least in one plane, with a measuring beam, a receiving unit for detecting by to be detected Objects in the surveillance area reflected light pulses and a control and evaluation unit for driving the transmitting unit, for evaluating the detected by the receiving unit light pulses and for determining a position of detected objects in the surveillance area based on a duration of detected light pulses and an angle at which the light pulses emitted were.

Optical measuring devices of this type are also referred to as 2D scanners.

A generic optical measuring device is known for example from EP 1 619 469 B1 ,

The measuring device described there is constructed comparatively complex, because both in the transmit beam path and in the receive beam path of the light beam is manipulated with a rotatable mirror.

As an object of the invention, it can be considered to provide an optical measuring device which is simpler and less expensive at substantially the same functionality as compared to the prior art.

This object is achieved by the optical measuring device having the features of claim 1.

The optical measuring device of the type specified above is inventively further developed in that the receiving unit is positioned stationary and that an acceptance angle of the receiving unit is so large and the receiving unit is positioned so far from the monitoring area that reflected light pulses from the entire monitoring area of the receiving unit receivable are.

Advantageous developments of the optical measuring device according to the invention will be described in the following description, in particular with reference to the dependent claims and the figures.

Optical measuring devices for detecting objects in a surveillance area are devices in which in some way the light emitted by objects in a spatial area, the surveillance area, or reflected light is used to detect them.

A rotatable deflection unit is a technical device for deflecting a light beam in which at least one rotatable component is present. Typically, such a deflection unit has a rotating mirror. In principle, however, other beam manipulating components can be rotated.

A movement of a continuously deflected light beam over a certain volume of space, namely the surveillance area, is referred to as sweeping the surveillance area. Typically, this sweeping is done at least in one plane with a measuring beam. By this is meant that the area of space acted upon by the light beam lies at least partially in one plane. In principle, however, the space area irradiated with light can also have other shapes, for example the shape of a cone sheath.

In the context of this description, light is defined as electromagnetic radiation in the wavelength ranges which are typically used in optical sensors, that is to say substantially visible light and infrared light. However, the principles of the invention described herein do not depend in detail on the wavelength used. Light pulses are short pulses of electromagnetic radiation, which may for example have a length in the range of nanoseconds to microseconds. Basically, it is important that the pulses are suitable for transit time measurements for distance determination.

In principle, all sources of electromagnetic radiation which provide the radiation in the desired wavelength range with the desired intensity can be used as the transmitting unit. Particularly preferably, in the optical measuring device according to the invention, the transmitting unit have at least one semiconductor emitter, in particular a light emitting diode (LED), a laser, a VCSEL (English: vertical cavity surface emitting laser) and / or a RCLED (English: resonant cavity light emitting device). ,

In principle, all devices which detect the electromagnetic radiation sufficiently sensitively in the wavelength ranges used can be used as the receiving unit and with regard to structural requirements (size) are suitable. In particular, these devices must also be suitable for the detection of short light pulses. In advantageous embodiments of the optical measuring device according to the invention, the receiving unit has at least one photodiode, in particular a PIN diode (English: positive intrinsic negative diode) or an avalanche photodiode.

A control and evaluation unit is an electronic component with which the control and evaluation tasks necessary for the measuring device according to the invention can be carried out. Typically, multifunctional, in particular programmable, devices such as microcontrollers or FPGAs are used. These devices can have both digital and analog functions, such as digital-to-analog converters and timing modules.

In the present invention, a position of objects detected in the surveillance area is determined based on a duration of detected light pulses. This means that a time difference between a transmission time and the time at which the reflected light pulse is detected is measured. Multiplication with the speed of light then provides the distance covered, which corresponds to twice the distance of the object from the measuring device. If, in addition, an angle information, namely the angle at which the light pulse was emitted and received, is evaluated, the position of an object in the monitoring area in a measuring plane can be determined. Because the amount of time that a light pulse passes from the transmitter to the object and back to the receiver is negligible compared to periods of time in which the deflection unit rotates significantly, the evaluation may assume that the position of the deflection unit is equal during transmission and reception is.

The angle at which the light pulses are emitted is functionally related to an angular position of the rotatable deflection unit. An equivalent condition for the control and evaluation unit to be set up to determine a position of a detected object depending in particular on the angle at which the light pulses were emitted is accordingly that the position is determined as a function of an angular position of the rotatable deflection unit. For detecting the angular position of the rotatable deflection angle measuring devices basically known type can be used.

Essential for the present invention is that the receiving unit is stationary. This means, in particular, that the receiving unit, unlike the transmitting unit, in which the measuring beam is moved over or through the monitoring area, detects light from a constant, thus temporally non-changing detection area or area (unless aperture means are present, see below ). In a particularly preferred variant of the measuring device according to the invention, the receiving unit is free of moving parts. Thus, according to the invention, situations are situations in which the receiving unit can basically receive light pulses from the entire monitoring area. However, it is also considered according to the invention if further means, for example diaphragms, are present in order to actively and specifically reduce the acceptance angle of the receiving unit.

In the strict sense, the term acceptance angle of the receiving unit refers to that solid angle from which incoming radiation can be detected by the receiver. Basically, the opening area does not have to be cone-shaped. For example, the opening angle, in one direction, approximately in the measuring plane (also this opening angle is referred to here as the acceptance angle) be greater, typically some 10 °, as in a plane perpendicular thereto, where it may be, for example, only up to 10 °.

With the feature that the acceptance angle is so large and the receiving unit is positioned so far away from the surveillance area that reflected light pulses from the entire surveillance area are receivable by the receiving unit, it should be expressed that the positioning of the receiving unit relative to the surveillance area the device according to the invention is such that the receiving unit, without having to be moved, can detect light pulses from the entire surveillance area.

It can therefore be regarded as a core idea of the present invention to reduce the effort on the receiving side by using a receiving unit and aligning it with the monitoring area in such a way that it can receive light pulses from the outset in principle from the outset.

The invention has recognized that it is sufficient to achieve sufficient functionality to guide only the transmit beam through and over the surveillance area. As a result, the costs and costs can be significantly reduced without having to accept losses in terms of functionality.

The main idea of the invention is thus a simply constructed 2-D scanner with rotatable deflection unit for the transmission beam and fixed Build up receiver. For the deflection of a thin transmission beam z. B. a laser beam is a small deflection sufficient. The necessary space can be reduced in an advantageous manner. The receiver is fixed and will not move. Thus, a total of a 2-D scanner in a very small space can be realized.

In order to avoid any disadvantages of a comparatively large receiving surface, which is also sensitive to disturbances such as ambient or scattered light, synchronizing diaphragm means synchronized with the deflecting unit can be used, which unlock the respectively required receiver region. Preferred variants for this purpose are described below.

Separating the transmitter and receiver also allows for better optical isolation, reducing crosstalk between transmitter and receiver.

Such scanners are suitable, for example, for collision protection applications.

In principle, the receiving unit can have a single light detector, possibly also with a comparatively large receiving surface. In preferred embodiments of the optical measuring device according to the invention, the receiving unit has a plurality of individual detectors which are each aligned in different spatial directions on the monitoring area. The receiving unit can be constructed from comparatively inexpensive and available individual detectors.

In principle, it is important for the realization of the invention that the receiving unit is positioned so that light pulses from the entire monitoring area can be detected. In addition, however, boundary conditions, for example with regard to the arrangement of the components in a housing, are generally to be considered. It can be exploited here that the receiving units and light detectors typically used have a non-zero acceptance angle transversely to a measuring plane. This means that the receiving unit does not necessarily have to be positioned exactly in the measuring plane. Preferred variants of the optical measuring device according to the invention are therefore characterized in that the receiving unit is arranged offset in relation to a given by a rotational axis of the deflection unit direction to the transmitting unit. This results in advantages with regard to the arrangement of the individual components in a housing.

In principle, the invention is realized when the receiving unit is stationary and can receive light pulses from the entire monitoring area from the outset. However, it may be advantageous to take measures to at least temporarily reduce the acceptance angle of the receiving unit. Thus, embodiments of the optical measuring device according to the invention may be expedient in which a selection device is present, in particular as part of the receiving unit, for at least temporarily changing the acceptance angle of the receiving unit and for setting a receiving direction of the receiving unit. For example, this selection device can be controlled by the control and evaluation unit or else be part of the control and evaluation unit.

Particularly preferably, the selection device has variable electronic and / or mechanical diaphragm means. As a result, only that angle range or solid angle range of the receiving unit can be activated at a specific point in time, from which light pulses reflected at the same time from the monitoring range are expected. Possibly from other directions of the surveillance area incident on the receiving unit light, such as stray light can be suppressed. The signal-to-noise ratio of the measurement can be increased so advantageous.

Thus, embodiments are advantageous, which are characterized in that the control and evaluation unit is arranged to operate the selection device such that the receiving unit is active only for that receiving direction from which, taking into account a current rotational position of the deflection of the monitoring range reflected transmission pulses expected become.

These advantages can also be achieved in embodiments in which the individual detectors with the selection device can be activated separately.

Advantageously, in the case of the optical measuring device according to the invention, the control and evaluation unit can be set up to actuate the selection device in such a way that the receiving unit, in particular only, activates that single detector or those individual detectors for or for the one under consideration of a current rotational position of the deflection unit from the monitoring area reflected transmission pulses are expected.

The possibility of the acceptance angle of the receiving unit with the selection device Targeted manipulation provides additional advantageous applications. For example, the control and evaluation unit can also be set up to operate the selection device such that the receiving unit also activates at least one further individual detector of the individual detectors for which no reflected transmission pulses are expected, taking into account the current rotational position of the deflection unit from the monitoring area, a measurement signal of this another single detector is used as a monitor signal for an existing background radiation. The term background radiation refers to any stray or interfering radiation. The information thus obtained about a background radiation can then be taken into account in the evaluation.

With regard to the specific embodiment of the deflection unit can be used in principle to known technical solutions. In principle, it is important that the monitoring area is penetrated as effectively as possible by the transmitted light, ie the measuring beams. However, it must also be considered that the receiving unit can not detect and process incoming light pulses at any desired time density. Embodiments in which the deflection unit of the transmitting unit has at least two reflection surfaces, in particular four reflection surfaces, are particularly preferred.

In order to increase the volume of space penetrated by light, that is to say the monitoring area as such, it may be advantageous if the measuring beams are not all guided in the same plane through the monitoring area. Technically, this can be realized in such a way that the reflection surfaces of the deflection unit have different angles of incidence for irradiating different levels of the surveillance area.

To increase the accuracy of the position determination, it may be expedient to position reference marks in the monitoring area or within the measuring device, for example in a housing of the measuring device, at defined positions, ie at a known distance and at a known angular position. These may be, for example, small reflectors. Thus, variants of the invention are advantageous in which reference marks are present for reference measurements in the monitoring area and / or within the measuring device. In addition, when using reference marks with a defined reflectivity, reference measurements can be made not only in terms of angle and distance, but also in terms of the amplitude, ie the intensity, of the reflected light.

In principle, the control and evaluation unit can also be set up to take into account an amplitude or an energy content of a detected light pulse for object identification and object recognition, for example by comparison with learned-in values. The reason for this is that different objects generally also have a different reflectivity, ie a different reflectivity, for the transmitted light used in each case.

In order to provide a user with information about where exactly the surveillance area is, it may be advantageous if the transmission unit has a main light source and an additional light source as pilot light source arranged to have the same surveillance points as one of the Main light source emitting measuring beam illuminated in the surveillance area. Preferably, the pilot light source emits light in the visible range.

In expedient embodiments, the main light source and the pilot light source are arranged opposite one another.

The information provided by the pilot light source is particularly accurate when the light of the main light source and the light of the pilot light source are coaxially reflected in a transmission beam path. To accomplish this mirroring, semi-transparent mirrors can be used. Impact points of the beam of the main light source and the pilot light source are then identical. One obtains accurate information about which part of the surveillance area is being scanned.

Also preferred are variants of the optical measuring device according to the invention, in which the deflection unit has two units arranged one above the other, which are offset by 90 ° with respect to the axis of rotation. The transmitted light radiated in different planes of the surveillance area is in this way phase-shifted with respect to the sweeping of the respective subarea of the surveillance area by 90 ° to one another. As a result, the commissioning of the receiving unit with light pulses is extended in time and the utilization of the receiving unit can be improved.

The amount of information obtained per unit time can also be increased by the fact that the transmitting unit has a plurality of synchronized transmission modules. For example, when using two synchronized transmission modules, the amount of information obtained per unit time can in principle be doubled.

With regard to the time measurement necessary for determining the transit time, known solutions can be used in principle. In Depending on the desired accuracy of the time measurement, configurations of the optical measuring device according to the invention may be preferred in which the control and evaluation unit for performing an analog time measurement, in particular based on a charging or discharging of a capacitor, and / or for performing a digital Timing, in particular for counting counting pulses, is set up.

For the use of the optical measuring device according to the invention, it is important that the measurement results, for example information about objects detected in the monitoring area, are transmitted to a user or to other devices. It is likewise desired that information, for example learned reference values via reference objects or calibration values, can be transmitted to the measuring device itself. In this context, developments of the optical measuring device according to the invention are preferred in which an interface device, in particular a human-machine interface, a non-contact optical interface and / or an NFC interface (NCF: Near Field Communication), is present for transfer from information to and / or from the control and evaluation unit. In principle, known interfaces and interface protocols, for example bus protocols, can be used in this regard.

• 1: ein Ausführungsbeispiel einer erfindungsgemäßen optischen Messvorrichtung;
• 2: ein Ausführungsbeispiel einer Empfangseinheit für eine erfindungsgemäße optische Messvorrichtung;
• 3: ein zweites Ausführungsbeispiel einer Empfangseinheit für eine erfindungsgemäße optische Messvorrichtung; und
• 4: ein drittes Ausführungsbeispiel einer Empfangseinheit für eine erfindungsgemäße optische Messvorrichtung.

Further characteristics and advantages of the invention are explained below with reference to the attached schematic figures. Show:

• 1 : an embodiment of an optical measuring device according to the invention;
• 2 : an embodiment of a receiving unit for an optical measuring device according to the invention;
• 3 a second embodiment of a receiving unit for an optical measuring device according to the invention; and
• 4 A third exemplary embodiment of a receiving unit for an optical measuring device according to the invention.

Identical and equivalent components and components are generally provided with the same reference numerals in the figures.

A first embodiment of an optical measuring apparatus 100 according to the present invention will be described with reference to FIG 1 explained. In the 1 shown inventive optical measuring device 100 has as essential components a transmitting unit 20 for emitting light pulses 24 into a surveillance area 40 , a receiving unit 30 and a control and evaluation unit 50 on. A coordinate system serves to describe the geometric relationships 70 wherein the x-direction is the vertical direction, the y-direction is the horizontal direction and z-direction is the normal direction to the paper plane, ie the direction perpendicular to the paper plane. The transmitting unit 20 has a light source 22 on, for example, a laser or a light emitting diode, for emitting transmitted light 23 in the form of light pulses 24 , Typically, transmitted light is used in the infrared or visible range of the electromagnetic spectrum. In addition, the transmitting unit includes 20 a rotatable deflection unit 26 , with the direction of rotation in 1 with the reference number 28 is marked. The axis of rotation is oriented parallel to the z-axis. In the z-direction below the transmitting unit 20 is the receiving unit 30 , in the 1 only shown schematically. The transmitting unit 20 is connected to the control and evaluation unit via a connection 21 and the receiving unit 30 is with the control and evaluation unit 50 over a connection 31 connected. The connections 21 . 31 may be, for example, cable connections. For interaction with a user or with other components, for example via a data bus, the control and evaluation unit 50 an interface device 60 on that in 1 through connections 62 is illustrated. The interface device 60 may be a human-machine interface, but also an optical, NFC or other interface of basically known type, such as a bus interface.

The optical measuring device 100 according to the invention operates as follows: From the light source 22 in the form of light pulses 24 emitted transmitted light 23 arrives at the rotatable deflection unit 26 , In the in 1 shown embodiment, it is a rotating mirror 26 with a total of four reflection surfaces 27 , The of the rotating mirror 26 reflected rays arrive as measuring beams 25 in the surveillance area 40 and paint this in the example shown in the measurement level 42 in the counterclockwise direction. The angular stroke over which the surveillance area 40 and therefore the extension of the surveillance area 40 is limited is in 1 with the angle α designated.

In the in 1 shown situation is a measuring beam 25 in an azimuthal angle φ relative to the x-axis. The in this measuring beam 25 contained light pulses 24 meet an object 10 which is at a distance d under the angle φ in the surveillance area 40 in the trade fair level 42 located. On this object 10 reflected light pulses 34 be in the direction of the receiving unit 30 returned and proved by this. That of the receiving unit 30 proven light pulses 34 are, optionally after a pre-amplification, which can still be done in the receiving unit 30, to the control and evaluation 50 passed. Based on a transmission time for the light pulses 24 and a reception time for the back-reflected light pulse 34 determines the control and evaluation unit 50 a term. Multiplication by the speed of light then provides the distance traveled by the light pulses, ie twice the distance d , In addition, because of an angular position of the rotatable deflection of the angle φ under which the corresponding light pulse 24 is known, so can total the coordinates of the location at which the light pulse 24 was reflected, in other words, the location of the object 10 to be measured. The obtained coordinates are in this case the azimuthal angle φ and the distance d ,

The surface normals of the four reflection surfaces 27 of the rotating mirror 26 can be exactly in the xy plane. In addition, if the light pulses 24 also in the xy plane on the reflection surfaces thus formed 27 are irradiated, sweep the measuring beams 25 from the rotating mirror 26 go out, a surveillance area 40 exactly in the xy plane, which is then a measurement plane 42 forms.

But it is also possible that the surface normals of, in particular four, reflection surfaces 27 the rotatable deflection unit 26 are slightly against each other and slightly inclined to the xy plane. That leads to that of the individual reflecting surfaces 27 outgoing reflected measuring beams 25 in turn tilted slightly upwards or downwards relative to the plane of the paper. That means more than one measurement level 42 with the transmitted light pulses 24 is enforced. In principle, it is then also possible to obtain information as to whether a detected object has been detected 10 in the plane of measurement given by the plane of the paper 42 or above or below.

Essential to the invention is that an acceptance angle ү the receiving unit 30 is so large and that the receiving unit objected to the surveillance area in a manner 40 is positioned remotely, that reflected light pulses 34 in principle from the entire surveillance area 40 from the receiving unit 30 can be received. In the in 1 example shown is the acceptance angle ү the receiving unit 30 the same size as the opening angle a over which the surveillance area 40 with measuring beams 25 is swept over. Of importance for the realization of the invention is that the opening angle ү greater or equal to the angle a ,

Details of variants of the receiving unit 30 be with reference to the 2 to 4 explained. 2 shows an embodiment in which the receiving unit 30 a plurality of individual detectors 81, 82, 83 has. Each of these individual detectors 81, 82, 83 has a main detection direction φ1, φ2 and φ3, respectively, as shown in FIG 2 can be seen, are aligned relative to the x-direction in each case in different azimuthal directions. Expediently, but not necessarily, the main detection directions φ1, φ2 and φ3 lie in one and the same measurement plane 42 , In addition, in the exhibition level 42 the individual detectors 81, 82, 83 have an acceptance angle of 11, 22 or 33. Acceptance angles, such as 1, 2 or 3, may or may not be the same.

As can be seen, there is a first area 71 before the single detectors 81 and 82 and a second area 72 before the individual detectors 82 and 83, which are not covered by any of the detection areas of the individual detectors 81, 82, 83. This means that the individual detectors 81, 82, 83 are at a certain distance from the monitoring area 40 need to be in place to ensure that actually from all places in the surveillance area 40 back-reflected transmission pulses 34 can be detected. It is understood that the receiving unit 30 also suitable relative to the transmitting unit 20 must be positioned. In essence, the receiving unit should be 30 located at the location of which also the emitted transmitted light pulses 24 go out, compare to this 1 , The distance in which the surveillance area 40 at the in 2 is removed from the individual receivers 81, 82, 83, is marked with a. Overall, this results with this distance a and with the opening angle α (see 1 ) of the spatial area, with the measuring beams 25 and finally with a maximum distance dmax , from the reflected light pulses 34 can still be demonstrated, the outer contour of the surveillance area 40 , α is at most as large as the angle range covered by the union of the 11, 22 and 33.

In the in 2 shown situation, the monitoring area 40 the shape of a circular segment on. In the direction perpendicular to the paper plane is the surveillance area 40 limited by an acceptance angle (in 2 not shown) of the individual detectors 81, 82, 83, which may for example be 5 °, and by the individual measurement planes, which, for example, when a deflection unit with tilted reflection surfaces is used, in turn may be tilted by corresponding angle (see description to 1 above). For controlling the individual detectors 81, 82, 83 is a selection device 52 , in particular part of the control and evaluation unit 50 can be present. With the selection device 52 can they Single detectors 81, 82, 83 are controlled either together or individually.

In connection with 3 becomes an alternative to a receiving unit 30 described in the selection device 52 angle-discriminating aperture means 53 having. The diaphragm means extend in the example shown semicircular and are between the individual detectors 81, 82, 83, 84 and the monitoring area 40 positioned. The arrangement of the individual detectors 81, 82, 83, 84 is, except for the fact that in 3 a total of four individual detectors 81, 82, 83, 84 are present, in principle similar to in 2 , At the aperture means 53 In principle, it can be any type of optical component with which a dimming of a light beam can be performed. In principle, it is possible that mechanical screens are present, which can be opened or closed. Preferably, however, electronic diaphragms, for example based on liquid crystals, are used.

With the property of being angular discriminating, it is meant that with the aperture means 53 the radiation targeted, in particular only, in individual angular segments and / or can be blocked in individual angle segments. In the in 3 shown situation are the aperture means 53 in an angular segment 54 open, but otherwise closed. That means that through this angular segment 54 from an object 10 in the surveillance area 40 reflected light pulses 34 pass through and in the direction of the light pulse 34 seen behind arranged single detector 82 can be detected.

In principle, for the variant of the 3 the receiving unit does not consist of individual detectors 81, 82, 83, 84. It could also be used a detector that is sensitive to the whole azimuthal region. Using the iris agents 53 Then only the respective subarea of the azimuthal angle would be selected, from the concretely reflected light pulses 34 to be expected. As a result, as with the variant with individual detectors 81, 82, 83, 84, the advantage would be achieved that the entry of stray light or stray light on the detector is reduced. In the embodiment with individual detectors, moreover, only the respective detector in which in 3 shown situation, ie the single detector 82, are activated for the back in the respective measurement situation light pulse 34 to be expected.

The selective activation of individual detectors 81, 82, 83, 84, each covering a portion of the azimuth angle (as related to 2 described) opens up even more possibilities. At the in 4 shown situation in which as in 3 a receiving unit 30 with four individual detectors 81, 82, 83, 84 is present, the single detector 82 is activated to detect light pulses 34 that of an object 10 in the surveillance area 40 were reflected. In addition, as far as possible from the individual detector 82, the individual detector 84, from the receiving direction no reflected light pulses 34 expected to be active. The received signal of the single detector 84 can then be used as a monitor signal for background light 90 be used. Under background light in particular any stray light and scattered light should be understood. Basically, this functionality can also be achieved by using the in 3 described Blendenmittel 53 , in which case next to the angle segment 54 another, from the segment 54 spaced angular segment of the diaphragm means 53 would be open. If there are single detectors, as in 4 It can easily be distinguished whether the detected light is true received light from reflected light pulses 34 or backlight 90 is. However, the functionality described last can also be achieved with a non-segmented detector by the background light 90 is measured only at times when no reflected light pulses 34 hit the detector.

With the present invention, a novel optical measuring device is provided which, with a simplified construction and thus reduced costs with high functionality, enables a 2D position determination of objects in a monitoring area.

LIST OF REFERENCE NUMBERS

10

object

20

transmission unit

21

connection

22

Main light source

23

Light of the main light source 22

24

light pulses

25

measuring beam

26

rotatable deflection unit

27

reflective surfaces

28

Direction of rotation of the deflection unit

30

receiver unit

31

connection

34

reflected light pulses

40

monitoring area

42

Level of the surveillance area

50

Control and evaluation unit

52

selection means

53

diaphragm means

54

Angular segment of the diaphragm means 53

60

Interface device

62

connections

70

coordinate system

71

first area in front of the individual detectors 81 and 82

72

second area in front of the individual detectors 82 and 83

81 - 84

individual detectors

90

Background radiation

92

reference marks

a

d

dmax

α

Opening angle of the monitoring area

β

Receiving direction in the receiving unit is currently active

ү

total acceptance angle of the receiving unit 30

ү1 - ү3

Acceptance angle of the single detectors

φ

Angle, under the light pulses 24 were sent out

φ1 - φ3

Main detection directions in which individual detectors are aligned

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1619469 B1 [0004]

Claims (22)

Optical measuring device for monitoring and detecting objects in a monitoring area (40), comprising at least one transmitting unit (20) for emitting light pulses (24) into the monitoring area (40), the transmitting unit (20) having a rotatable deflection unit (26) for Sweeping over the monitoring area (40), in particular at least in one plane (42), with a measuring beam (25), with a receiving unit (30) for detecting light pulses (34) reflected by objects to be detected (10) in the monitoring area (40) and with a control and evaluation unit (50) for controlling the transmitting unit (20), for evaluating the light pulses (34) detected by the receiving unit (30) and for determining a position of detected objects (10) in the monitoring area (40) on the basis of a Running time of detected light pulses (34) and an angle (φ), under which the light pulses (24) were emitted, characterized in that the receiving unit (30) fixed p and that an acceptance angle ()) of the receiving unit (30) is so large and the receiving unit (30) is positioned far enough away from the surveillance area (40) to reflect reflected light pulses (34) from the entire surveillance area (40) Receiving unit (30) are receivable. Optical measuring device according to Claim 1 , characterized in that the receiving unit (30) is free of moving parts. Optical measuring device according to one of Claims 1 or 2 , characterized in that the receiving unit (30) comprises a plurality of individual detectors (81, 82, 83, 84) which are each aligned in different spatial directions (φ1, φ2, φ3) on the monitoring area (40). Optical measuring device according to one of Claims 1 to 3 , characterized in that the receiving unit (30) with respect to a given by a rotational axis of the deflection unit (26) direction (z) is arranged offset to the transmitting unit (20). Optical measuring device according to one of Claims 1 to 4 , characterized in that a selection device (52) is present, in particular as part of the receiving unit (30) or the control and evaluation unit (50) for at least temporarily changing the acceptance angle ()) of the receiving unit (30) and for setting a receive direction (β) the receiving unit (30). Optical measuring device according to Claim 5 , characterized in that the selection device (52) has variable electronic and / or mechanical diaphragm means (53). Optical measuring device according to one of Claims 5 or 6 , characterized in that the individual detectors (81, 82, 83, 84) with the selection device (52) are separately activated. Optical measuring device according to one of Claims 5 to 7 , characterized in that the control and evaluation unit (50) is arranged to actuate the selection device (52) such that the receiving unit (30) is active only for that receiving direction (β), from taking into account a current rotational position of the deflection unit (26) from the monitoring area (40) reflected transmission pulses (34) are expected. Optical measuring device according to one of Claims 5 to 8th , characterized in that the control and evaluation unit (50) is arranged to actuate the selection device such that the receiving unit (30), in particular only, that single detector (81, 82, 83, 84) activated for the taking into account a current Rotary position of the deflection unit (26) from the monitoring area (40) reflected transmission pulses (34) are expected. Optical measuring device according to Claim 9 , characterized in that the control and evaluation unit (50) is arranged to actuate the selection device in such a way that the receiving unit (30) also activates at least one further individual detector (84) of the individual detectors (81, 82, 83, 84) for which taking into account the current rotational position of the deflection unit (26) from the monitoring area (40) no reflected transmission pulses (34) are expected, a measurement signal of this further single detector (84) is used as a monitor signal for an existing background radiation (90). Optical measuring device according to one of Claims 1 to 10 , characterized in that the deflection unit (26) of the transmitting unit (20) has at least two reflection surfaces, in particular four reflection surfaces (27). Optical measuring device according to Claim 11 , characterized in that the reflection surfaces (27) of the deflection unit (26) for irradiating different levels (42) of the monitoring area (40) have different angles of incidence. Optical measuring device according to one of Claims 1 to 12 , characterized in that for Reference measurements in the monitoring area (40) and / or within the measuring device, in particular within a housing, reference marks (92) are present. Optical measuring device according to one of Claims 1 to 13 , characterized in that the transmitting unit (20) comprises a main light source (22) and an additional light source as a pilot light source arranged to illuminate the same monitoring points as a measuring beam emanating from the main light source (22) in the surveillance area (40) , Optical measuring device according to Claim 14 , characterized in that the main light source (22) and the pilot light source are arranged opposite to each other. Optical measuring device according to Claim 14 or 15 , characterized in that light (23) of the main light source (22) and the light of the pilot light source are coaxially reflected in a transmission beam path. Optical measuring device according to one of Claims 1 to 16 , characterized in that the deflection unit (26) has two superimposed units, which are offset relative to the axis of rotation by 90 ° to each other. Optical measuring device according to one of Claims 1 to 17 , characterized in that the transmitting unit (20) comprises a plurality of synchronized transmitting modules. Optical measuring device according to one of Claims 1 to 18 , characterized in that the control and evaluation unit (50) for performing an analog time measurement, in particular based on a charging or discharging a capacitor, and / or for performing a digital time measurement, in particular for counting counting pulses, is set up. Optical measuring device according to one of Claims 1 to 19 , characterized in that the transmitting unit (20) has at least one semiconductor emitter, in particular an LED, a laser, a VCSEL and / or an RCLED. Optical measuring device one of Claims 1 to 20 Characterized in that the receiving unit (30) comprises at least a photodiode, in particular a PIN-diode or an avalanche photodiode. Optical measuring device one of Claims 1 to 21 , characterized in that an interface device (60), in particular a man-machine interface, a non-contact optical interface and / or an NFC interface, is present for transferring information to and / or from the control and evaluation unit ( 50).

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