CUMULATIVE SHORT PULSE EMISSION FOR PULSED LIDAR DEVICES INCLUDING A LONG EXPOSURE TIME

Abstract

A method for operating a LIDAR device using a control unit. At least one radiation source is activated to generate pulsed beams and the pulsed beams are emitted into a scanning area. The beams that are reflected or backscattered in the scanning area are received by a receiving optical system and guided onto a detector. An amplitude profile of a reference pulse is emulated by the pulsed beams of the at least one radiation source. It is possible to generate and emit multiple pulsed beams temporally quickly one after the other. The pulsed beams have an increasingly ascending and subsequently once again descending amplitude as a function of time. The pulsed beams have a pulse duration, which is shorter than a pulse duration of the reference pulse. The pulsed beams are temporally spaced apart from one another by breaks.

Claims

1-14. (canceled)

15. A method for operating a LIDAR device using a control unit, the method comprising the following steps: activating, by the control unit, at least one radiation source to generate pulsed beams, the pulsed beams being emitted into a scanning area; and receiving beams that are reflected and/or backscattered in the scanning area, the beams being received by a receiving optical system and being guided onto a detector; wherein an amplitude profile of a reference pulse is emulated by the pulsed beams of the at least one radiation source.

16. The method as recited in claim 15, wherein the pulsed beams are generated by the at least one radiation source in an amplitude-modulated manner.

17. The method as recited in claim 15, wherein an envelope curve modulation of the pulsed beams is carried out using the reference pulse as the envelope curve.

18. The method as recited in claim 15, wherein the pulsed beams are generated by the at least one radiation source to have the same pulse width.

19. The method as recited in claim 15, wherein the pulsed beams are generated by the at least one radiation source in a temporally modulated manner.

20. The method as recited in claim 15, wherein the pulsed beams are generated by the at least one radiation source in a sectionally overlapping manner.

21. The method as recited in claim 20, wherein an overlap of the pulsed beams is implemented by activating at least two radiation sources in an offset manner and/or by reactivating the at least one radiation source while generating a pulsed beam.

22. The method as recited in claim 15, wherein the pulsed beams are generated by the at least one radiation source at a variable temporal distance to one another.

23. The method as recited in claim 22, wherein the temporal distances for setting a signal-to-noise ratio are adaptively set.

24. The method as recited in claim 15, wherein the pulsed beams are generated by the at least one radiation source in a wavelength-modulated manner.

25. A control unit configured to operate a LIDAR device, the control unit configured to: activate, at least one radiation source to generate pulsed beams, the pulsed beams being emitted into a scanning area; and receive beams that are reflected and/or backscattered in the scanning area, the beams being received by a receiving optical system and being guided onto a detector; wherein an amplitude profile of a reference pulse is emulated by the pulsed beams of the at least one radiation source.

26. A LIDAR device for scanning a scanning area using pulsed beams, comprising: at least one radiation source operable by a control unit; and a receiving optical system configured to receive and forwarding beams that are reflected and/or backscattered in the scanning area onto at least one detector; wherein the at least one radiation source is operable by the control unit in such a way that multiple pulsed beams emulate a wider reference pulse in an amplitude-modulated manner.

27. A non-transitory machine-readable memory medium on which is stored a computer program for operating a LIDAR device using a control unit, the computer program, when executed by the control unit, causing the control unit to perform the following steps: activating at least one radiation source to generate pulsed beams, the pulsed beams being emitted into a scanning area; and receiving beams that are reflected and/or backscattered in the scanning area, the beams being received by a receiving optical system and being guided onto a detector; wherein an amplitude profile of a reference pulse is emulated by the pulsed beams of the at least one radiation source.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 shows a schematic illustration of a LIDAR device according to one specific embodiment of the present invention.

[0031] FIG. 2 shows a schematic diagram for the purpose of illustrating pulsed beams that were generated with the aid of a method according to one specific embodiment of the present invention.

[0032] FIG. 3 shows a schematic diagram for the purpose of illustrating pulsed beams that were generated by a method according to a further specific embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0033] FIG. 1 shows a schematic illustration of a LIDAR device 1 according to the present invention according to one specific embodiment. LIDAR device 1 is used to scan a scanning area B using pulsed beams 2.

[0034] LIDAR device 1 includes a radiation source 4 according to the exemplary embodiment. Radiation source 4 is designed as an infrared laser that is operable in a pulsed manner.

[0035] Alternatively or in addition, further radiation sources 5 may be inserted into LIDAR device 1.

[0036] Radiation sources 4, 5 are connected to a control unit 6. Control unit 6 is configured to activate radiation sources 4, 5.

[0037] For example, control unit 6 may be designed as a driver or as an activation of radiation sources 4, 5. Control unit 6 may preferably activate the radiation sources at defined times and at a defined duration in such a way that radiation sources 4, 5 generate and emit pulsed beams 2.

[0038] Radiation sources 4, 5 may be situated in parallel next to one another, so that pulsed beams 2, 3 of particular radiation sources 4, 5 are slightly offset. Alternatively, a beam divider (not illustrated) or an optical coupling element may be used to configure pulsed beams 2, 3 to a defined exit location.

[0039] Furthermore, LIDAR device 1 includes a receiving optical system 8. Receiving optical system 8 may be designed as one or multiple lenses, lens systems, diffractive optical elements, filters, and the like. Together with radiation sources 4, 5 or in contrast to radiation sources 4, 5, receiving optical system 8 may be designed to be pivotable, rotatable, movable or immovable.

[0040] Receiving optical system 8 is used to receive beams 10 that are reflected and/or backscattered in scanning area B and to guide them onto a detector 12.

[0041] Detector 12 of LIDAR device 1 may preferably be an imaging detector. In particular, detector 12 may be designed as a CCD sensor or as a CMOS sensor.

[0042] Control unit 6 may also be connected to detector 12 in a data transferring manner. Alternatively, detector 12 may be read out by a separate control unit or evaluation unit and the corresponding measured data may be evaluated.

[0043] In this case, control unit 6 controls at least one radiation source 4, 5 in such a way that multiple pulsed beams 2 emulate a wider reference pulse in an amplitude-modulated manner.

[0044] FIG. 2 shows a schematic diagram for the purpose of illustrating pulsed beams 2 to emulate a reference pulse 14, which were generated with the aid of a method according to one specific embodiment.

[0045] In the diagram, an amplitude A is plotted against time t. Reference pulse 14 is designed similarly to a Gaussian curve and represents a beam that is advantageous for an optimal exposure of detector 12.

[0046] As a result of the activation of radiation sources 4, 5 by control unit 6, it is possible to generate and emit multiple pulsed beams 2 temporally quickly one after the other. Amplitude A of pulsed beams 2 is adjusted by control unit 6 to an amplitude profile of reference pulse 14. Pulsed beams 2 thus have an increasingly ascending and subsequently once again descending amplitude A as a function of time t.

[0047] Pulsed beams 2 have a pulse width or pulse duration D. Pulse duration D is in this case shorter than a pulse duration of reference pulse 14. Furthermore, pulsed beams 2 are temporally spaced apart from one another by breaks P according to the illustrated exemplary embodiment. By extending breaks P between pulsed beams 2, the power density of the emitted radiation of LIDAR device 1 may be reduced and the risk of eye injury may be decreased.

[0048] FIG. 3 shows a schematic diagram for the purpose of illustrating pulsed beams 2, 3 that were generated with the aid of a method according to a further specific embodiment. Pulsed beams 2, 3 were generated by two radiation sources 4, 5 that may be activated independently from one another. Pulsed beams 2 of a first radiation source 4 have a shorter pulse duration D3 than pulse duration D1, D2 of pulsed beams 3 of a second radiation source 5.

[0049] Pulsed beams 2, 3 are generated in such a way that they sectionally overlap. In particular, an overlap 16 results between temporally adjacent beams 2, 3. In this way, reference pulse 14 may be emulated more precisely.

[0050] Analogously to the diagram illustrated in FIG. 2, particular pulsed beams 2, 3 are designed in an amplitude-modulated manner, so that maximal amplitude A of particular pulsed beams 2, 3 follows or corresponds to the amplitude profile of reference pulse 14.

[0051] Pulsed beams 2, 3 have different pulse widths D1, D2, D3 that are set with the aid of a temporal modulation of control unit 6 when activating radiation sources 4, 5.

[0052] According to the exemplary embodiment, there are no pulse distances P between pulsed beams 2, 3.