DE102018215177A1 - Autofocus and particle sensor device and corresponding method, as well as camera and particle sensor system - Google Patents

Abstract

The invention relates to a combined autofocus and particle sensor device (1a; 1b; 1c) with an optical emitter device (2) which is designed to emit at least one measuring laser beam (L) into the surroundings of the combined autofocus and particle sensor device (1a; 1b; 1c) send out; and a detector device (3) which is designed to detect the at least one measurement laser beam (L) scattered on particles or objects (6) in the vicinity of the combined autofocus and particle sensor device (1a; 1b; 1c) and a corresponding one Output measurement signal. An evaluation device (4) is designed to use the measurement signal in a first operating mode to determine at least one measurement variable with regard to the particles in the vicinity of the combined autofocus and particle sensor device (1a; 1b; 1c); and to generate a control signal for adapting a focus of an external camera (5) in a second operating mode.

Description

The present invention relates to a combined autofocus and particle sensor device. The invention further relates to a combined camera and particle sensor system. Finally, the invention relates to a combined autofocus and particle measurement method. In particular, the invention relates to combined autofocus and particle sensor devices and corresponding measurement methods for use in mobile devices, in particular in smartphones.

State of the art

In many larger cities with a high volume of traffic or in industrial areas, the air pollution, which arises in particular due to particulate matter, can become problematic. In order to measure the exceedance of limit values or to identify certain problem areas, measurements are carried out by public institutes or scientific research institutions in order to determine the particle load. However, there is also an increasing demand in the private sector for possibilities to determine the particle load locally. There is therefore a need for portable, miniaturized sensors for detecting the particle load.

The particle load can be determined, for example, on the basis of optical measurements. One example is an optical particle sensor from the WO 2017/198699 A1 known. A laser sensor module has a plurality of lasers which emit measurement laser beams which are reflected on particles in the vicinity of the particle sensor. Properties of the particles in the vicinity of the particle sensor can be determined using a self-mixing interference method (SMI method). An SMI method is understood to mean that the reflected measurement laser beams interfere with the transmitted measurement laser beams, the interference leading to changes in the optical and electrical properties of the laser. The exact determination of the changes allows conclusions to be drawn about the properties of the particles.

Another exemplary optical particle sensor for detecting particle densities of small particles with particle sizes in the range between 0.05 μm and 10 μm is shown in US Pat WO 2018/104153 A1 known.

In addition to optical sensors, portable devices such as smartphones typically include cameras for capturing images and videos. While the focus of the camera was traditionally set manually, most modern cameras, and in particular cameras from portable devices such as smartphones, tablets or notebooks, have an auto focus ( AF ), ie a technique that automatically focuses on a subject. A distinction is made here between active autofocus and passive autofocus, electromagnetic radiation, for example ultrasound or an auxiliary light, being emitted during active autofocus, while passive autofocus only uses the light emitted or reflected by the subject.

Passive autofocus systems include edge contrast measurement, whereby the image width of the lens is varied and the brightness curve at contour edges is maximized. Other passive methods include phase comparison, line sensors and cross sensors.

Active autofocus systems include time-of-flight methods, a distance between objects being determined on the basis of the time-of-flight of ultrasonic waves or laser beams reflected on the objects. An AF auxiliary light can be used in order to be able to use passive methods, such as contrast measurement or phase comparison, even when the object is poorly illuminated.

Several sensors are typically required for various sensor functions, in particular for determining properties of particles, and for an autofocus function of a camera, which represents a high overall expenditure and can lead to space problems of the portable devices.

Disclosure of the invention

The invention provides a combined auto focus and particle sensor device with the features of claim 1, a combined camera and particle sensor system with the features of claim 8 and a combined auto focus and particle measurement method with the features of claim 10.

Preferred embodiments are the subject of the respective subclaims.

According to a first aspect, the invention accordingly relates to a combined autofocus and particle sensor device with an optical emitter device, a detector device and an evaluation device. The optical emitter device is designed to emit at least one measurement laser beam into the surroundings of the combined autofocus and particle sensor device. The detector device detects the at least one measurement laser beam scattered on particles or objects in the vicinity of the combined autofocus and particle sensor device and outputs a corresponding measurement signal. The evaluation device is designed to use the measurement signal in a first operating mode to determine at least one measurement variable with regard to the particles in the vicinity of the combined autofocus and particle sensor device, and to generate a control signal for adapting a focus of an external camera in a second operating mode.

According to a second aspect, the invention relates to a combined camera and particle sensor system, with a camera and a combined auto focus and particle sensor device, which is designed to adapt the focus of the camera with the aid of the control signal.

According to a third aspect, the invention relates to a combined autofocus and particle measurement method, wherein at least one measurement laser beam is emitted and the at least one measurement laser beam scattered on particles or objects is detected and a corresponding measurement signal is output. In a first method mode, a measurement variable relating to the particles is determined using the measurement signal, and in a second method mode, a control signal for adapting a focus of a camera is generated using the measurement signal.

Advantages of the invention

The device according to the invention can be used both for an autofocus function and as a particle sensor. The two operating modes or operating methods (autofocus mode or method and particle sensor mode or method) can either be independent of one another, i.e. successively in time, or also used or carried out simultaneously. Since only a single, common optical emitter device and a corresponding detector device are required for both functions, the combined autofocus and particle sensor device can be designed to be very compact, so that the required installation space is reduced, which is particularly advantageous in the case of portable devices such as smartphones. By eliminating several independent sensors, the manufacturing costs are further reduced.

According to a preferred development of the combined autofocus and particle sensor device, the measuring principle of the detector device is based on a self-mixing interference method (SMI method), i.e. the at least one emitted measuring laser beam interferes with the corresponding scattered measuring laser beam. The measurement signal can be generated based on a photo current from photo diodes of the detector device.

According to a preferred development of the combined autofocus and particle sensor device, the evaluation device is designed to calculate a distance of an object from the combined autofocus and particle sensor device in the second operating mode using the measurement signal and to generate the control signal as a function of the calculated distance. In particular when using an SMI method, the distance can be determined very quickly and precisely, as a result of which a lengthy adjustment of the focus, for example by means of edge contrast measurement, in which several test images have to be generated until the optimum focus is reached.

According to a development of the combined autofocus and particle sensor device, the evaluation device is designed to calculate a speed amount and / or a direction of movement of an object in the vicinity of the autofocus and particle sensor device in the second operating mode using the measurement signal and as a function of the calculated speed amount and / or to predict a setting of the focus of the external camera at a future point in time in the calculated direction of movement of the object and to generate the control signal accordingly. According to a further development, the instantaneous distance of the object from the autofocus and particle sensor device can be measured using the measurement signal and the distance of the object from the autofocus and particle sensor device can be predicted at least at a future time using the calculated speed amount and / or the calculated direction of movement become. More generally, the trajectory of the object can be calculated so that the focus can always be focused on the object, the control signal being generated accordingly.

The optical emitter device of the combined autofocus and particle sensor device can emit any number of measurement laser beams. In particular, the emitter device can also emit only a single measurement laser beam. However, it is preferred that the optical emitter device emits a multiplicity of measurement laser beams, that is to say at least two measurement laser beams. In particular, the optical emitter device can be designed to emit at least three measurement laser beams in different spatial directions. Assuming a homogeneous particle flow, the projections of vectorial particle properties, for example a speed or acceleration of the particles of the particle flow, onto the different spatial directions can be determined when using at least three measuring laser beams. Since the spatial directions differ, the vectorial particle properties can be completely reconstructed. When using four or more measuring Laser beams have certain redundancies, which means that additional plausibility checks can be carried out to improve the reliability of the results.

According to a preferred development of the autofocus and particle sensor device, the optical emitter device is designed to emit a large number of measurement laser beams, the optical emitter device emitting only a subset of the measurement laser beams in an energy-saving mode and / or the detector device in the energy-saving mode only one Part of the scattered measurement laser beams are detected and the measurement signal is output. The energy-saving mode can be used both in the first operating mode, i.e. in the particle sensor mode as well as in the second operating mode, i.e. in autofocus mode, but can also be used for both operating modes. According to some embodiments, the energy-saving mode can always be executed in the first operating mode or always in the second operating mode.

According to a preferred development of the combined autofocus and particle sensor device, the measurement variable with respect to the particles comprises one or more of reflection amplitudes, Doppler shifts, particle velocity amounts, particle distances, particle movement directions, particle sizes, particle distributions, particle size distributions, particle densities and a reflectivity. The measurement variable with regard to the particles can thus include any optically detectable properties of the particles.

According to a preferred development of the combined autofocus and particle sensor device, the evaluation device is designed to use different filters for evaluating the measurement signal in the first operating mode and in the second operating mode. In particular, different bandwidths can be filtered and used in a Fast Fourier transformation.

According to a preferred development of the combined autofocus and particle sensor device, the optical emitter device has at least one laser diode. Alternatively or additionally, the detector device can have at least one photodiode. The laser diode can be a VCSEL (vertical cavity surface emitting laser). This is to be understood as a light-emitting diode in which the light is emitted perpendicular to the plane of the semiconductor chip. The at least one photodiode can be integrated into a corresponding laser diode.

According to a preferred development of the combined camera and particle sensor system, the optical emitter device of the combined autofocus and particle sensor device is designed to emit the at least one measurement laser beam into a surrounding area of the combined autofocus and particle sensor device which overlaps at least partially with a detection area of the camera.

According to a preferred development of the combined autofocus and particle measurement method, a distance of an object is calculated in the second method mode using the measurement signal, and the control signal is generated as a function of the calculated distance.

According to a development of the combined autofocus and particle measurement method, a speed amount and / or a direction of movement of an object are calculated in the second method mode using the measurement signal. Depending on the calculated speed and / or the calculated direction of movement of the object, a setting of the focus of the camera is predicted at a future point in time. The control signal is generated accordingly.

According to a preferred development of the combined autofocus and particle measurement method, a multiplicity of measurement laser beams are emitted, only a subset of the measurement laser beams being emitted in an energy-saving mode. Alternatively or additionally, only a subset of the scattered measurement laser beams can be detected in the energy-saving mode and the corresponding measurement signal can be output.

According to a preferred development of the combined autofocus and particle measurement method, the measurement variable with respect to the particles comprises one or more of reflection amplitudes, Doppler shifts, particle velocity amounts, particle distances, particle movement directions, particle sizes, particle distributions, particle size distributions, particle densities and a reflectivity.

According to a preferred development of the combined autofocus and particle measurement method, different filters are used to evaluate the measurement signal in the first method mode and in the second method mode.

Figure list

• 1 ein schematisches Blockdiagramm einer kombinierten Autofokus- und Partikelsensorvorrichtung gemäß einer Ausführungsform der Erfindung;
• 2 eine schematische Schrägansicht einer kombinierten Autofokus- und Partikelsensorvorrichtung gemäß einer weiteren Ausführungsform der Erfindung;
• 3 ein schematisches Blockdiagramm zur Erläuterung der Partikelsensor-Funktion der kombinierten Autofokus- und Partikelsensorvorrichtung;
• 4 ein schematisches Blockdiagramm zur Erläuterung der Einstellung des Autofokus;
• 5 ein schematisches Blockdiagramm einer kombinierten Autofokus- und Partikelsensorvorrichtung gemäß einer weiteren Ausführungsform der Erfindung; und
• 6 ein schematisches Flussdiagramm eines kombinierten Autofokus- und Partikelmessverfahrens.

Show it:

• 1 a schematic block diagram of a combined autofocus and particle sensor device according to an embodiment of the invention;
• 2nd a schematic oblique view of a combined autofocus and particle sensor device according to a further embodiment of the invention;
• 3rd a schematic block diagram for explaining the particle sensor function of the combined autofocus and particle sensor device;
• 4th a schematic block diagram for explaining the setting of the autofocus;
• 5 a schematic block diagram of a combined autofocus and particle sensor device according to a further embodiment of the invention; and
• 6 a schematic flow diagram of a combined autofocus and particle measurement method.

The same or functionally identical elements and devices are provided with the same reference symbols in all the figures. The numbering of procedural steps is for clarity and should generally not imply any particular chronological order. In particular, several process steps can also be carried out simultaneously.

Description of the embodiments

1 FIG. 12 shows a schematic block diagram of a combined autofocus particle sensor device 1a according to a first embodiment of the invention. This includes an optical emitter device 2nd , a detector device 3rd and an evaluation device 4th . The optical emitter device 2nd preferably comprises a plurality of laser diodes designed as VCSELs, which corresponding measuring laser beams L emit. The evaluable distance range can be maximized and the desired resolution achieved through optimized beam shaping. When using several laser diodes, the measuring laser beams are preferably emitted in different spatial directions by means of suitable lens and / or mirror devices. The detector device 3rd comprises photodiodes, the number of photodiodes corresponding to the number of laser diodes. The photodiodes are preferably integrated into the laser diodes. The measuring laser beams emitted L be on an object 6 , for example a hand of a user, or on particles 6 , such as dust particles, around the auto focus and particle sensor device 1 reflected and captured by the photodiodes. The object or the particles 6 can be static or moving.

The evaluation device 4th includes a self-mixing interference analysis function, which reduces the interference of the emitted and the reflected measurement laser beams L is recorded. In particular, a photocurrent of the photodiodes can be measured and output as a measurement signal.

The evaluation device 4th works in two operating modes, which can be selected, for example, based on user input. In a first operating mode or particle sensor mode, the measurement signal is evaluated in order to determine a measurement variable with regard to the particles in the vicinity of the combined autofocus and particle sensor device 1 to determine, in the second operating mode, a drive signal for adjusting a focus of an external camera 5 is generated and output.

When evaluating the measurement signal by the evaluation device 4th Several processing steps can be carried out, in particular downsampling (English decimation) to change the frequency range, a Fast Fourier transformation ( FFT ), a binning step to combine multiple pixel values, and a particle or object detection to detect the presence of a particle or object 6 . The specific parameters used depend on the operating mode, ie for example for the FFT different frequency ranges are taken into account by means of respective filters.

In each operating mode, the optical emitter device 2nd and the detector device 3rd from the evaluation device 4th can be controlled accordingly. In particular, the laser diodes of the emitter device 2nd be operated in a first phase, the drive current of the laser diodes being modulated in order to achieve a desired resolution, which enables faster object detection. When modulating the current, a Doppler shift occurs and the evaluation device 4th can use the measurement signal to determine the distance between objects or particles 6 determine. The laser diodes of the emitter device 2nd can continue to be operated in a second phase, the drive current of the laser diodes being constant or static, ie not being modulated. The speed of the objects or particles can be determined on the basis of Doppler shifts 6 can be determined, or the residence time can be determined, ie the time during which the object or the particle 6 in the detection area of the respective measuring laser beam L stops. For every measuring laser beam L can be a scalar speed or speed component of the objects or particles 6 be determined and the vectorial speed of the objects or particles 6 can from the evaluation device 4th can be calculated using the respective speed components. The vectorial speed of the objects or particles 6 thus includes both the absolute amount of speed of the objects or particles 6 as well as the direction of movement of the objects or particles 6 .

In the first operating mode or particle sensor mode, the evaluation device determines 4th based on the evaluated measurement signal particle estimates for the number of particles per volume, ie a number density of the particles. The evaluation device calculates on the basis of the particle estimates for the number of particles per volume 4th further a particle load. In particular, the evaluation device 4th Use the particle estimates for the number of particles per volume and with the help of a model that shows the distribution of the sizes or diameters of the dust particles and the distribution of the mass and density of the dust particles. For example, PMx values can be calculated, whereby only particles up to a certain diameter x are taken into account, such as coarse dust, fine dust and / or ultra fine dust values.

The evaluation device generates in the second operating mode or autofocus mode 4th the drive signal for adjusting a focus of the external camera 5 . As soon as the evaluation device 4th here an object 6 the distance and optionally the speed of the object are recognized as described above 6 certainly. The control signal is generated depending on the calculated distance. In addition, based on the speed of the object 6 a trajectory can be calculated so that the auto focus is automatically adjusted and the camera 5 thus on the object 6 remains in focus.

The combined autofocus and particle sensor device 1a can be operated in succession in the first operating mode or in the second operating mode. However, it is also possible for the measurement signal to be sent through the evaluation device 4th to be evaluated in parallel in both operating modes, so that both the particle detection and the generation of the control signal are carried out simultaneously.

Furthermore, the combined autofocus and particle sensor device 1a be operated in an energy-saving mode, with at least one of the laser diodes of the optical emitter device 2nd is deactivated. Alternatively or additionally, the detector device 3rd only a subset of the scattered measuring laser beams L detect and output the measurement signal accordingly.

The camera 5 and the combined auto focus and particle sensor device 1 form a combined camera and particle sensor system.

2nd shows a schematic oblique view of a combined autofocus and particle sensor device 1b according to a second embodiment of the invention. Accordingly, the optical emitter device comprises three laser diodes 71 , 72 , 73 what laser beams L1 , L2 , L3 essentially perpendicular to the surface of a common substrate 74 send out, which by means of a carrier 75 arranged deflection device 76 be distracted in different spatial directions and through an opening 77 of the carrier 75 emerge. The deflector 76 can have lenses or mirror elements. Regarding the other components and the functional principle of the combined autofocus and particle sensor device 1b can be referred to the first embodiment described above.

3rd shows a schematic block diagram for explaining the particle sensor function of the combined autofocus and particle sensor device 1a . It therefore sends at least one measuring laser beam L from which of particles 6 is reflected. As described above, the autofocus and particle sensor device determines 1 at least one measured variable with regard to the particles 6 which to a host processor 8th is issued for further processing.

4th shows a schematic block diagram for explaining the setting of the autofocus of the camera 5 . The camera includes an auto focus processor 53 and an auto focus motor 52 , as well as a lens 51 . The control signal, which from the evaluation device 4th the combined autofocus and particle sensor device 1a is generated is sent to the autofocus processor 53 which transmit the autofocus motor 52 drives such that the lens 51 is correctly focused according to the control signal.

5 shows a schematic block diagram of a combined autofocus and particle sensor device 1c according to a third embodiment of the invention. The optical emitter device 2nd includes a laser drive in addition to the laser diodes described above 21 , which sets the drive current of the laser diodes. An LF modulation control unit 22 controls the laser drive 21 in the first phase described above, wherein the drive current of the laser diodes is modulated. The modulation takes place at a low frequency (English: low-frequency, LF ). A static laser control unit 23 controls the laser drive 21 in the second phase described above, ie with a constant drive current without modulation. The detector device further comprises 3rd a photo front-end facility 31 which the photocurrent of the photodiodes of the detector device 3rd measures. A signal processing device 41 the evaluation device 4th is trained to process the photo stream further. The signal processing device 41 for this purpose comprises an autofocus-specific first signal processing unit 411 , a shared second signal processing unit 412 and a particle sensor specific third signal processing unit 413 . The first signal processing unit 411 and the third signal processing unit 413 can comprise filters which are specially designed for the respective operating modes, while the second signal processing unit 412 can be used both in the first operating mode and in the second operating mode for evaluating the photocurrent. Due to the shared functionality of the second signal processing unit 412 can reduce the complexity of the combined autofocus and particle sensor device 1 compared to individual sensors. The LF modulation control unit 22 , the static laser control unit 23 and the signal processing device 41 can through a host interface 42 the evaluation device 4th can be controlled.

6 shows a schematic flow diagram of a combined autofocus and particle measurement method. The method can be carried out using an autofocus and particle sensor device described above. In particular, all of the functionalities described above can also be transferred to the method, and conversely the method steps described below can be carried out using one of the above-described autofocus and particle sensor devices.

In a first step S1 is at least one measuring laser beam L sent out. Several laser measuring beams are preferred L and preferably emits at least three measuring laser beams in different spatial directions.

In a second step S2 the at least one measuring laser beam L which on particles or objects 6 was scattered, detected. A corresponding measuring signal is generated and output using a self-mixing interference method.

In one step S3 it is determined whether the method is to be carried out in a first method mode or in a second method mode. The first method mode corresponds to the above-described first operating mode of the combined autofocus and particle sensor device and the second method mode corresponds to the above-described second operating mode of the combined autofocus and particle sensor device.

In the first process mode, in a further process step S4 determines at least one measurement variable with regard to the particles in the vicinity of the combined autofocus and particle sensor device. In particular, as described in more detail above, the speed, the distance, the number of particles per volume or a particle load can be calculated and output.

The second process mode is in a further process step S5 a drive signal for adjusting a focus of a camera 5 generated. The control signal is calculated taking into account a calculated distance and a calculated speed of an object 6 determines which are calculated based on the measurement signal.

However, the invention is not limited to the embodiment shown. So it is particularly possible to follow the process steps S4 , S5 to be carried out in parallel, ie at the same time a measured variable with regard to the particles 6 to determine and the drive signal for adjusting a focus of the camera 5 to generate. Furthermore, it is possible to reduce the number of channels in a power saving mode, ie individual ones of the laser diodes of the optical emitter device 2nd to deactivate.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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.

Patent literature cited

• WO 2017/198699 A1 [0003]
• WO 2018/104153 A1 [0004]

Claims (15)

Combined autofocus and particle sensor device (1a; 1b; 1c), with: an optical emitter device (2) which is designed to emit at least one measuring laser beam (L) into the surroundings of the combined autofocus and particle sensor device (1a; 1b; 1c) ) send out; and a detector device (3) which is designed to detect the at least one measurement laser beam (L) scattered on particles or objects (6) in the vicinity of the combined autofocus and particle sensor device (1a; 1b; 1c) and a corresponding one Output measurement signal; characterized by an evaluation device (4), which is designed to use the measurement signal: a. in a first operating mode to determine at least one measurement variable with regard to the particles in the vicinity of the combined autofocus and particle sensor device (1a; 1b; 1c); and b. generate a control signal for adapting a focus of an external camera (5) in a second operating mode. Combined autofocus and particle sensor device (1a; 1b; 1c) after Claim 1 The evaluation device (4) is designed to calculate a distance of an object (6) from the combined autofocus and particle sensor device (1a; 1b; 1c) in the second operating mode using the measurement signal and to control the control signal as a function of the calculated distance to generate. Combined autofocus and particle sensor device (1a; 1b; 1c) after Claim 1 or 2nd The evaluation device (4) is designed to calculate a speed and / or a direction of movement of an object (6) in the vicinity of the autofocus and particle sensor device (1a; 1b; 1c) in the second operating mode using the measurement signal and as a function thereof to predict a setting of the focus of the external camera (5) at a future point in time of the calculated speed amount and / or the calculated direction of movement and to generate the control signal accordingly. Combined autofocus and particle sensor device (1a; 1b; 1c) according to one of the preceding claims, wherein the optical emitter device (2) is designed to emit a plurality of measurement laser beams (L), the optical emitter device (2) being in an energy-saving mode. is set up to emit only a subset of the measurement laser beams (L) and / or the detector device (3) in the energy-saving mode is set up to detect only a subset of the scattered measurement laser beams (L) and to output the measurement signal. Combined autofocus and particle sensor device (1a; 1b; 1c) according to one of the preceding claims, wherein the measurement variable with respect to the particles (6) comprises at least one of reflection amplitudes, Doppler shifts, particle velocity amounts, particle distances, particle movement directions, particle sizes, particle distributions, particle size distributions, particle densities and reflectivity includes. Combined autofocus and particle sensor device (1a; 1b; 1c) according to one of the preceding claims, wherein the evaluation device (4) is designed to use different filters for evaluating the measurement signal in the first operating mode and in the second operating mode. Combined auto focus and particle sensor device (1a; 1b; 1c) according to one of the preceding claims, wherein the optical emitter device (2) has at least one laser diode, in particular a VCSEL, and the detector device (3) has at least one photodiode, in particular one in the at least one has a laser diode integrated photodiode. Combined camera and particle sensor system, with a camera (5) and a combined auto focus and particle sensor device (1a; 1b; 1c) according to one of the preceding claims, which is designed to adjust the focus of the camera (5) with the aid of the control signal. Combined camera and particle sensor system according to Claim 8 , wherein the optical emitter device (2) of the combined autofocus and particle sensor device (1a; 1b; 1c) is designed to direct the at least one measuring laser beam (L) into a surrounding area of the combined autofocus and particle sensor device (1a; 1b; 1c) to be sent, which overlaps at least partially with a detection area of the camera (5). Combined autofocus and particle measurement method, with the steps: emitting (S1) at least one measurement laser beam (L); and detecting (S2) the at least one measurement laser beam (L) scattered on particles or objects (6) and outputting a corresponding measurement signal; characterized in that in a first method mode, using the measurement signal, at least one measurement variable with respect to the particles (6) is determined (S4); and in a second method mode using the measurement signal, a control signal for Adjusting a focus of a camera (5) is generated (S5). Combined autofocus and particle measurement method according to Claim 10 A distance of an object (6) is calculated using the measurement signal in the second method mode and the control signal is generated as a function of the calculated distance. Combined autofocus and particle measurement method according to one of the Claims 10 or 11 , In the second method mode, using the measurement signal, a speed amount and / or a direction of movement of an object (6) are calculated and, depending on the calculated speed amount and / or the calculated direction of movement, a setting of the focus of the camera (5) is predicted at a future point in time and the control signal is generated accordingly. Combined autofocus and particle measurement method according to one of the Claims 10 to 12th , wherein a plurality of measurement laser beams (L) are emitted, only a subset of the measurement laser beams (L) being emitted in an energy-saving mode and / or wherein only a subset of the scattered measurement laser beams (L) is detected in the energy-saving mode and the corresponding measurement signal is output. Combined autofocus and particle measurement method according to one of the Claims 10 to 13 , The measurement variable with respect to the particles (6) comprising at least one of reflection amplitudes, Doppler shifts, particle velocity amounts, particle distances, particle movement directions, particle sizes, particle distributions, particle size distributions, particle densities and a reflectivity. Combined autofocus and particle measurement method according to one of the Claims 10 to 14 , Different filters being used to evaluate the measurement signal in the first method mode and in the second method mode.

Images