Patent Publication Number: US-2021181315-A1

Title: Multi-pulse lidar system for multi-dimensional detection of objects

Description:
FIELD 
     The present invention relates to a multipulse LIDAR system for multidimensional detection of objects in an observation area of the multipulse LIDAR system. Moreover, the present invention relates to a method for multidimensional detection of objects in an observation area with the aid of such a multipulse LIDAR system. 
     BACKGROUND INFORMATION 
     LIDAR systems are used, among other things, for detecting objects in the surroundings of vehicles. Such a LIDAR system scans its surroundings with the aid of pulsed or time-modulated laser radiation, the light radiation that is emitted by a laser source of the LIDAR system being reflected or scattered on objects in the surroundings and once again received in the LIDAR system with the aid of a detector. During the scanning, the laser beam is successively moved along a scanning direction, and the objects situated in the observation area in question are detected. The relative position of a detected object in relation to the vehicle is ascertained via the corresponding angle of the laser beam and the distance information ascertained with the aid of propagation time measurement of the single laser pulses. The LIDAR system may be designed in the form of a single-pulse LIDAR system or a multipulse LIDAR system. A single-pulse LIDAR system samples each sampling point with the aid of a single laser pulse in each case. A particularly high lateral resolution may thus be achieved. However, the system requires single laser pulses having relatively high laser power, for which reason a correspondingly powerful laser source is required. In contrast, much less laser power is used in the multipulse LIDAR system, in which a sampling point is sampled with the aid of multiple low-power single laser pulses in quick succession. Summing the individual measurements results in a suitable detector signal with a satisfactory signal-to-noise ratio. However, one disadvantage of this method is a reduction in the lateral resolution resulting from summing the individual measurements over a relatively large angular range, and accompanying “smearing” of the detector signal. 
     SUMMARY 
     An object of the present invention, therefore, is to provide a laser-based detection method for objects which operates according to the principle of a multipulse LIDAR system and therefore manages with relatively low laser power, and at the same time allows a relatively high lateral resolution. This object may be achieved by a multipulse LIDAR system according to example embodiments of the present invention. Moreover, the object may be achieved by a method in accordance with example embodiments of the present invention. Further advantageous specific embodiments are described herein. 
     According to the present invention, a multipulse LIDAR system for detecting objects in an observation area is provided. In accordance with an example embodiment of the present invention, the LIDAR system includes a transmitting device with at least one laser source for generating a transmission laser beam from a temporal sequence of single laser pulses, each of which illuminates a detection area that is limited to a portion of the observation area and samples at least one sampling point. In addition, the LIDAR system includes a receiving device with a detection surface, including a linear or matrix-like subdetector system made up of multiple subdetectors, adjacently situated in a first direction of extension, for receiving the transmission laser beam, in the form of a reception laser beam, that is reflected and/or scattered on objects in the observation area of the multipulse LIDAR system. The receiving device is designed to image a sampling point, detected by the transmission laser beam, on the detection surface in the form of a pixel. In addition, the LIDAR system includes a scanning device for generating a scanning movement of the transmission laser beam in a scanning direction for successive sampling of the entire observation area along multiple sampling points situated in succession in the scanning direction. The scanning movement of the transmission laser beam, for single laser pulses in chronological succession, is designed to image a pixel on the detection surface, in each case shifted along the linear or matrix-like subdetector system. Lastly, the LIDAR system includes a control device for determining distance information of the sampling points based on propagation times of the particular single laser pulses, the control device being designed to jointly evaluate subdetectors, which are detected from a pixel that is instantaneously imaged on the detection surface, in the form of a macropixel that is individually associated with the particular pixel. Due to the option for individually associating subdetectors with a macropixel, the position of the particular macropixel may be optimally adapted to the position of the pixel that represents the imaging of the particular sampling point on the detection surface. Optimal use may thus be made of the measuring energy of the particular sampling point. 
     In one specific embodiment of the present invention, it is provided that the control device is also designed to adapt the position of a macropixel on the detection surface by regrouping corresponding subdetectors subsequent to the shift, caused by the scanning movement, of the pixel associated with the particular macropixel on the detection surface. Optimal use may thus be made of the measuring energy and measuring time for the particular sampling point over multiple individual measurements. 
     In another specific embodiment of the present invention, it is provided that the transmitting device is designed to generate a transmission laser beam whose single laser pulses each illuminate a solid angle with at least two sampling points. The receiving device is designed to represent the two sampling points in the sampling range, instantaneously illuminated by the transmission laser beam, in the form of two pixels that are adjacently situated on the detection surface and that are shifted along the linear or matrix-like subdetector system due to the scanning movement. In addition, the control device is designed to group subdetectors, instantaneously detected by a first pixel of the two pixels, together to form a first macropixel that is associated with the first pixel, and to group subdetectors, instantaneously detected by a second pixel of the two pixels, together to form a second macropixel that is associated with the second pixel. The measuring time for each of the two sampling points is increased due to the joint sampling of multiple sampling points. More measuring energy is thus available for each sampling, thereby improving the signal-to-noise ratio. 
     According to another specific embodiment of the present invention, control device  130  is designed to associate subdetectors, which are detected by the first pixel in a first individual measurement that takes place with the aid of a first single laser pulse, and by the second pixel in a second individual measurement that takes place with the aid of a second single laser pulse immediately following the first single laser pulse, with the first macropixel for the first individual measurement, and with the second macropixel for the subsequent second individual measurement. Optimal use is thus made of the detection surface. 
     In another specific embodiment of the present invention, it is provided that the transmitting device includes multiple laser sources whose detection areas are mutually orthogonal with respect to the scanning direction. The detection surface for each laser source includes a subdetector system that is individually associated with the particular laser source, the subdetector systems being mutually orthogonal with respect to the scanning direction. The vertical resolution of the LIDAR system may be increased in this way. 
     Moreover, according to the present invention, a method for multidimensional detection of objects in an observation area with the aid of a multipulse LIDAR system is provided. In accordance with an example embodiment of the present invention, a transmission laser beam in the form of a temporal sequence of single laser pulses is generated in a first method step, the transmission laser beam with each single laser pulse illuminating a detection area that is limited to a subsection of the observation area and that samples at least one sampling point. A scanning movement of the transmission laser beam in a scanning direction is subsequently generated, resulting in successive sampling of the entire observation area at multiple successive sampling points in the scanning direction. A reception laser beam that is generated by reflection and/or scattering of the transmission laser beam on objects in the observation area is subsequently received on a detection surface that includes a linear or matrix-like subdetector system made up of multiple subdetectors adjacently situated in a first direction of extension, a sampling point on the detection surface, instantaneously detected by the transmission laser beam, being imaged in the form of a pixel that is successively shifted along the linear or matrix-like subdetector system due to the scanning movement of the transmission laser. Subdetectors whose positions correspond to the instantaneous position of the pixel are subsequently grouped to form a macropixel that is individually associated with the particular pixel. Lastly, the subdetectors associated with the particular macropixel are jointly evaluated. Due to the option for individually grouping subdetectors to form a macropixel, the position of the particular macropixel may be optimally adapted to the position of the pixel that represents the imaging of the particular sampling point on the detection surface. Optimal use may thus be made of the measuring energy for the particular sampling point. 
     In one specific embodiment of the present invention, it is provided that the signals, measured in multiple individual measurements for a certain macropixel, of the subdetectors associated with the particular macropixel in these individual measurements are jointly associated with a histogram that is associated with the particular macropixel. The measuring time made up of the individual measurements is thus evaluated jointly, which in particular results in a better signal-to-noise ratio. 
     In another specific embodiment of the present invention, it is provided that the position of a macropixel on the detection surface is successively adapted by regrouping corresponding subdetectors subsequent to a shift of the pixel on the detection surface, associated with the particular macropixel, that is caused by the scanning movement. Optimal use may thus be made of the measuring energy and measuring time of the particular sampling point over multiple individual measurements. 
     In another specific embodiment of the present invention, it is provided that multiple sampling points are simultaneously detected during an individual measurement, subdetectors that are detected by a first pixel that is generated by a first sampling point on the detection surface being associated with a first macropixel that is individually associated with the first sampling point. In addition, subdetectors that are detected by a second pixel that is formed by a second sampling point on the detection surface are associated with a second macropixel that is individually associated with the second sampling point. The measuring time for each of the two sampling points is increased due to the joint sampling of multiple sampling points. More measuring energy is thus available for each sampling, thereby improving the signal-to-noise ratio. 
     Lastly, in another specific embodiment of the present invention, it is provided that subdetectors that are detected by the first pixel during a first individual measurement and detected by the second pixel in a second individual measurement that takes place with the aid of a second single laser pulse immediately following the first single laser pulse are associated with the first macropixel for the first individual measurement, and with the second macropixel for the subsequent second individual measurement. Particularly optimal use is thus made of the detection surface, which also allows a particularly flexible measurement. 
     Example embodiments of the present invention is described in greater detail below with reference to the figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically shows a perspective illustration of the multipulse LIDAR system for explaining the rotational movement for scanning the observation area. 
         FIG. 2  shows a schematic illustration of a rotating LIDAR system during scanning of a vehicle that is situated in the observation area thereof. 
         FIGS. 3 through 5  show schematic illustrations of the LIDAR system according to an example embodiment of the present invention for explaining the sampling operation of an object with the aid of three successive single laser pulses. 
         FIG. 6  shows a diagram for explaining the shift of a pixel, imaged on the detection surface, as a function of the scanning movement. 
         FIGS. 7 through 9  show a schematic illustration of a sampling operation for an object for explaining the association of subdetectors with individual macropixels. 
         FIGS. 10 and 11  show a variation of the LIDAR system according to the present invention from  FIGS. 7 through 9 , with three sampling points simultaneously detected. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     The present invention makes possible a multipulse LIDAR system or macroscanner system which, despite use of multiple pulses for a measurement, achieves the same lateral resolution as a single-pulse LIDAR system. Since in a multipulse LIDAR system, a measurement is made up of multiple single pulses in order to improve the measuring accuracy or due to the use of special detectors or measuring principles (SPAD/TCSPC), the resolution of the system is limited for the measurement without suitable compensation for the angular difference between the emission of the first and the last single laser pulse. 
     To avoid this limitation, a row or an array made up of multiple small detectors or subdetectors is used instead of a single detector for receiving the measuring pulses. The rotational or scanning movement may be compensated for by suitably combining or grouping the subdetectors to form macropixels. The speed of the regrouping of the subdetectors results directly from the rotational speed of the sensor. The lateral resolution capability of such a design then corresponds to the resolution capability of a single-pulse approach. In addition, due to the parallel association of the single laser pulses with adjacent macropixels, no measuring energy or measuring time is lost. 
     In the LIDAR system according to an example embodiment of the present invention, an arrangement of multiple small detectors situated in a linear or matrix-like manner is used instead of a single detector for receiving individual measuring pulses. The rotational movement of the sensor head may be compensated for by suitably combining or regrouping these subdetectors to form larger macropixels. The speed of this regrouping of the subdetectors results directly from the rotational speed of the sensor. The lateral resolution capability of such a design corresponds to a single-pulse approach. Likewise, due to parallel association of the pulses with adjacent macropixels, no measuring energy or measuring time is lost. Detectors that operate according to various measuring principles, for example single photon avalanche photodiode (SPAD) or time-correlated single photon counting (TCSPC), may be used as subdetectors. 
       FIG. 1  shows a macro LIDAR system  100  with a rotating sensor head  101  that includes multiple transmitting units and receiving units situated at different angles, in the present example only transmitting device  110  being illustrated. Sensor head  101  carries out a rotating scanning movement  122 , rotational axis  102  extending in parallel to the Z axis in the present example. In this arrangement, the horizontal image resolution of the LIDAR system is determined by the rotational movement and the measuring rate. In contrast, the vertical image resolution is defined by the number and the particular angular distance of the receiving units. Sensor head  101  undergoes a complete revolution of 360° in the present exemplary embodiment. However, in each specific embodiment, the scanning movement may also be limited to a defined angular range. 
       FIG. 2  shows a schematic illustration of macro LIDAR system  100  from  FIG. 1  during a scanning operation, in which an object  400  (in the present case, a vehicle) situated in observation area  300  of LIDAR system  100  is sampled with the aid of laser radiation  200 . LIDAR system  100  includes a rotating sensor head  101  that includes a transmitting device  110  with at least one laser source  111 , and a receiving device  140  with a detection surface  141 . For each laser source, detection surface  141  includes a linear or matrix-like subdetector system  143  made up of multiple subdetectors  142   n  adjacently situated in a first direction of extension  144 . For reasons of clarity, only one linear subdetector system  143  including only three subdetectors  142   n  is illustrated in  FIG. 2 . 
     In the present exemplary embodiment, sensor head  101  also includes an optical imaging device  150 . This may involve, for example, one or multiple optical lens element(s) with the aid of which laser beams  210 ,  220  are shaped in the desired manner. In addition, as is the case in the present exemplary embodiment, sensor head  101  may include a beam splitter  121  for superimposing or separating transmission laser beams and reception laser beams  210 ,  220 . Such an optical beam splitter  121  may be designed in the form of a semitransparent mirror, for example. 
     As also shown in  FIG. 2 , LIDAR system  100  typically also includes a control device  130  for controlling transmitting devices and receiving devices  110 ,  140 . In the present example, control device  130  also includes a measuring device for ascertaining the propagation times of the emitted and received single laser pulses, as well as an evaluation device for ascertaining distance information of the sampling points based on the measured propagation times. Depending on the specific embodiment, control device  130  or its individual components may be situated outside sensor head  101  and connected to the particular devices in sensor head  101  with the aid of appropriate signal lines and data lines. Alternatively, control device  130  or its individual components may be accommodated within sensor head  101 . 
     During operation of LIDAR system  100 , each laser source of transmitting device  110  generates a dedicated transmission laser beam  210  in the form of a temporal sequence of brief single laser pulses. With each single laser pulse, transmission laser beam  210  illuminates a solid angle that defines detection area  310  of the particular single laser pulse, and that typically represents only a relatively small section of overall observation area  300  of LIDAR system  100 . Sampling of overall observation area  300  is achieved only by rotating scanning movement  122  and the accompanying successive shift of detection areas  310  of successive single laser pulses.  FIG. 2  illustrates, by way of example, a measuring sequence with three single laser pulses emitted in succession and their respective detection areas  310 . Detection areas  310  are depicted by a dashed line. Instantaneous detection area  310  of transmission laser beam  210  is illustrated as a circle in the present exemplary embodiment. However, depending on the application, the cross section of transmission laser beam  210 , which defines the shape of detection area  310 , may also have some other design, for example elliptical or approximately square. Due to scanning movement  122  of sensor head  101 , the individual single laser pulses are emitted at various angles, so that transmission laser beam  210  with its particular instantaneous detection area  310  migrates in predefined angular increments over object  400  that is sampled in each case. For the multipulse LIDAR system, the refresh rate of the single laser pulses and scanning movement  123  are in each case coordinated with one another in such a way that an area that is detected by transmission laser beam  210 , and thus the sampling points (not shown here) situated in the particular area, are sampled by multiple single laser pulses in direct succession during a scanning pass. 
     As shown in  FIG. 2 , transmission laser beam  210  that is reflected on object  400  or scattered back from object  400  is received in the form of a reception laser beam  220  in sensor head  101  and imaged on detection surface  141 . Due to scanning movement  122 , a sampling point that is situated in instantaneous detection area  310  and that may be, for example, a detail of vehicle  400 , is imaged on detection surface  141 , shifted in each case by a defined distance, with successive laser pulses. 
     The regrouping of subdetectors, via which a shift of the macropixels on the detection surface, and thus a compensation of the rotating scanning movement, is achieved, is described in greater detail below. For this purpose,  FIGS. 3 through 5  show the brief scanning sequence, already shown in  FIG. 2 , which includes the sampling of vehicle  400  with the aid of three single laser pulses.  FIG. 3  shows a first individual measurement in which vehicle  400  is illuminated with the aid of a first single laser pulse. Instantaneous detection area  310  detects at least a first sampling point  320   n  that is imaged on detection surface  141  in the form of a corresponding pixel  230   n . Pixel  230   n , depicted by a dashed circle, illuminates a total of nine subdetectors  142   i,j  of matrix-like subdetector system  143 , illustrated in dark crosshatch in  FIG. 3 . Subdetectors  142   i,j  in question are subsequently grouped to form a first macropixel  160   n  that represents first sampling point  320   n . The signals of grouped subdetectors  142   i,j  are jointly assigned to a histogram  170   n  that is associated with first macropixel  160   n . The signals of all subdetectors  142   i,j  associated with macropixel  160   n  during the overall measurement are added in this histogram  170   n . The signal-to-noise ratio may be improved in this way. 
     In contrast to  FIG. 2 , in the present exemplary embodiment, detection surface  141  includes a matrix-like subdetector system  143 , which in a first direction of extension  144  includes a total of fourteen adjacently situated subdetectors  142   i,j , and in a second direction of extension  145  includes a total of five subdetectors  142   i,j  situated in succession. 
     In the stage of the method shown in  FIG. 4 , transmission laser beam  210  is migrated further in scanning direction  123  due to scanning movement  122 . The instantaneous emitted second single laser pulse therefore includes a detection area  310  that is shifted by a certain angular extent in scanning direction  123 . As a result, the projection of first sampling point  320   n  and thus the position of first pixel  230   n  on detection surface  141  are also shifted by a defined amount. The shift of pixel  230   n  is a direct function of the imaging properties of the optical components as well as of the particular angular difference between the individual measurements, and thus, of scanning speed  122  and the measuring rate. In the present exemplary embodiment, these parameters are coordinated with one another in such a way that in successive individual measurements, sampling point  320   n  is imaged on the detection surface, in each case shifted by a distance that preferably corresponds exactly to the lateral width of subdetectors  142   i,j . This ensures that subdetectors  142   i,j  may always be unambiguously associated with one of macropixels  160   n . This also applies for specific embodiments in which the increments with which the pixels are imaged on the detection surface, shifted in subsequent individual measurements, are an integral multiple of the lateral width of subdetectors  142   i,j . However, depending on the particular application, the parameters in question of the LIDAR system may also be such that the increments with which the pixels are imaged on the detection surface, shifted in subsequent individual measurements, are in each case a fraction of the lateral width of the subdetectors. In addition, LIDAR systems may also be implemented in which the shift of the pixels on the detection surface is not in a rational ratio with the lateral width of subdetectors  142   i,j . This is possible in particular when directly adjacent sampling points are imaged on the detection surface at a distance that corresponds at least to the width of a subdetector. 
     As shown in  FIG. 4 , the shift of first pixel  230   n  on detection surface  141  due to scanning movement  122  has been compensated for by a corresponding shift of first macropixel  160   n  associated with first pixel  230   n . The shift of first macropixel  160   n  takes place due to a regrouping of subdetectors  142   i,j  in question. For this purpose, three new subdetectors  142   i,j  have now been assigned to first macropixel  160   n  on its right side. In contrast, the three subdetectors  142   i,j  in light crosshatch in  FIG. 4 , which in the preceding individual measurement were still associated with first macropixel  160 , are now associated with subsequent second macropixel  160   n+1 , which in a manner of speaking moves from the left into the active portion of subdetector system  143 . The signals of subdetectors  142   i , in dark crosshatch are assigned to histogram  170   n  of first macropixel  160   n , and the signals of subdetectors  142   i,j  in light crosshatch are assigned to histogram  170   n+1  of second macropixel  160   n+1 , depending on their respective associations. 
       FIG. 5  shows a stage of the method during the third individual measurement, which directly follows the second individual measurement illustrated in  FIG. 4 . The transmission laser beam is migrated to the right by a further angular extent due to the scanning movement, so that associated detection area  310  is now migrated further with respect to the first individual measurement shown in  FIG. 3 . Since the relative position of first sampling point  320   n  has changed in relation to instantaneous detection area  310 , first sampling point  320   n  is now imaged on detection surface  141 , shifted by a corresponding amount. As is apparent from  FIG. 5 , the overall shift of first pixel  230   n  compared to the situation from  FIG. 3  is now twice the lateral width of subdetectors  142   i,j . Similarly, the position of associated first macropixel  160   n  has also been changed by regrouping corresponding subdetectors  142   i,j  subsequent to the position of first pixel  230   n . In comparison to the arrangement from  FIG. 4 , three new subdetectors  142   i,j  have been assigned to first macropixel  160   n  on its right side. Similarly, the three subdetectors  142   i,j  depicted in light crosshatch in  FIG. 5 , which in the preceding individual measurement were still associated with first macropixel  160   n , are now associated with subsequent second macropixel  160   n+1 . As a result, the signals of all subdetectors  142   i,j  associated with one of macropixels  160   n ,  160   n+1  are respectively assigned to histogram  170   n ,  170   n+1  of macropixel  160   n ,  160   n+1  in question within the scope of the instantaneous individual measurement. 
       FIG. 6  shows a time diagram which depicts how subdetectors  142   i,j  of detection surface  141  are individually associated with various macropixels  160   n  in the course of a scanning operation. An ellipsoidal light spot  231  is illustrated, which is generated by the imaging of reception laser beam  220  on detection surface  141 . Light spot  231  extends over the entire active portion of detection surface  141 , which in the present case includes only five subdetectors  142   i,j  for purposes of explanation. During a scanning operation, in which transmission laser beam  210  is successively guided over successive sampling points due to the scanning movement, the sampling points in question are successively imaged on detection surface  141  in the form of pixels. The scanning movement thus results in the impression that the pixels, and thus the macropixels associated with them in each case, are migrating across detection surface  141 . In contrast, viewed from the perspective of the macropixels, the impression results that light spot  231 , which extends on detection surface  141  over the above-mentioned group of five subdetectors  142   i,j  in total, successively moves across a row of adjacently situated macropixels  160   n . This apparent movement of light spot  231  over a group of three successive macropixels in total is illustrated in the time diagram in  FIG. 6 . It is apparent that at point in time t 6 , all subdetectors  142   i,j  of the group in question are associated with the middle macropixel (pixel n). For the subsequent single laser pulse (pixel n+1) at point in time t 7 , of the group in question only four of the subdetectors  142   i,j  are now associated with the middle macropixel (pixel n), while one of subdetectors  142   i,j  of the group is already associated with the right of the three illustrated macropixels (pixel n+1). For a further single laser pulse (pulse i+2) at point in time t 8 , two of the subdetectors  142   i,j  of the group in question are already associated with the right macropixel (pixel n+2). In this way, for each single laser pulse, light spot  231  migrates by one subdetector in each case over the three macropixels (pixel n−1, pixel n, pixel n+1) illustrated here. It is thus apparent from the diagram that a subdetector  142   i,j , which is associated with a first macropixel during a first single laser pulse, is associated with a second macropixel following the first macropixel, no later than five further single laser pulses. 
     The relationship between the rotating scanning movement and the shift of a pixel on the detection surface is explained below. For this purpose,  FIGS. 7 through 9  show a sequence of the scanning operation that includes three individual measurements. A simplified specific embodiment of sensor head  101  is illustrated in each case, laser beams  235  being imaged directly on detection surface  141  with the aid of an optical imaging device  150 , without deflection by a beam splitter. As shown in  FIG. 7 , the emitted transmission laser beam with its conical detection area  310  detects an object  400  that is instantaneously situated in the viewing area of sensor head  101 . Detected object  400  is sampled at a certain sampling point  320   n . Sampling point  320   n  is defined by a certain solid angle, which in the present exemplary embodiment is much smaller than the solid angle that defines detection area  110 . The transmission laser beam is reflected back on object  400  and is received again in the form of a reception laser beam by sensor head  101  of LIDAR system  100 . Sampling point  320   n  associated with object  400  is imaged in the form of a pixel  230   n  on detection surface  141 . For better clarity, detection surface  141 , which in the present exemplary embodiment is designed as a two-dimensional subdetector system  143  in the form of a 12×8 matrix, is illustrated in both the side view and top view. 
     As is shown in  FIG. 7 , the total of sixteen subdetectors  142   i,j  in the present example detected by instantaneous pixel  230   n , depicted in dark crosshatch in  FIG. 7 , are grouped to form a macropixel  160   n  that is associated with the particular pixel. The grouping takes place by interconnecting the subdetectors, the signals detected by individual subdetectors  142   i,j  being summed to form a shared histogram. 
       FIG. 8  shows the arrangement from  FIG. 7  during the subsequent second individual measurement. Transmission laser beam  210  is migrated further in scanning direction  123  due to scanning movement  122 . Detection area  310  of the instantaneous single laser pulse is thus shifted by a certain angular extent in scanning direction  123 . Since sampling point  320   n  is instantaneously situated in the center of detection area  310 , first pixel  230   n , which represents the projection of first sampling point  320   n , is also imaged centrally on detection surface  141 . Compared to the preceding individual measurement, first pixel  230   n  on detection surface  141  has a shift by a defined distance in first direction of extension  144 , which in the present case corresponds to twice the lateral width of the subdetectors. To compensate for the shift of pixel  230   n  on detection surface  141  caused by scanning movement  122  of sensor head  101 , the control device of LIDAR system  100  also shifts the position of macropixel  160   n  associated with pixel  230   n  by the particular distance by activating and deactivating appropriate subdetectors. 
       FIG. 9  shows the arrangement from  FIGS. 7 and 8  during the subsequent third individual measurement. Due to scanning movement  122  of sensor head  101 , transmission laser beam  210  and thus also its detection area  310  are further migrated in scanning direction  123  by the same angular extent as before. Thus, from the perspective of sensor head  101 , sampling point  320   n  is shifted further to the left by the corresponding angular extent. Consequently, first pixel  230   n  is migrated on the detection surface to the right in first direction of extension  144  by twice the lateral width of subdetectors  142   i,j . Associated first macropixel  160   n  has also been shifted to the right by two subdetectors  142   i,j  by regrouping corresponding subdetectors  142   i,j  subsequent to first pixel  230   n . 
       FIGS. 10 and 11  show another specific embodiment in which multiple laterally adjacent sampling points are simultaneously sampled with each single laser pulse. The measuring arrangement corresponds essentially to the arrangement from  FIGS. 7 through 9 . As is apparent from  FIG. 10 , detection area  310  of transmission laser beam  210  includes a total of three sampling points  320   n−1 ,  320   n ,  320   n+1  adjacently situated in scanning direction  123 . Only middle sampling point  320   n  is completely detected, while the two outer sampling points  320   n−1 ,  320   n+1  are not completely situated in instantaneous detection area  310 . The three sampling points  320   n−1 ,  320   n ,  320   n+1  are imaged on various areas of detection surface  141 . Three macropixels  160   n ,  160   n+1  associated with respective sampling points  320   n−1 ,  320   n ,  320   n+1  are simultaneously generated on detection surface  141  by activating and grouping corresponding subdetectors  142   i,j , each macropixel including sixteen subdetectors  142   i,j  and in each case being separated from one another by a column of subdetectors.  FIG. 11  shows the arrangement from  FIG. 10  during a subsequent second individual measurement. As is apparent, transmission laser beam  210  and thus also its instantaneous detection area  310  are migrated further in scanning direction  123  by a defined angular extent due to scanning movement  122 . From the viewpoint of sensor head  101 , the three sampling points  320   n−1 ,  320   n ,  320   n+1  are shifted to the left, opposite scanning direction  123 , by the same angular extent, left sampling point  320   n−1  having almost completely exited from detection area  110 , while right sampling point  320   n+1  now having completely entered into detection area  310 . Pixels  230   n−1 ,  230   n ,  230   n+1  generated by projections  235   n−1 ,  235   n ,  235   n+1  of the sampling points have been correspondingly shifted on detection surface  141  by a distance that corresponds to twice the lateral width of a subdetector. To compensate for this shift, macropixels  160   n ,  160   n+1  associated with respective pixels  230   n−1 ,  230   n ,  230   n+1  have also been shifted by twice the lateral width of a subdetector by regrouping corresponding subdetectors  142   i,j . As is apparent from a comparison of  FIGS. 10 and 11 , for shifting middle macropixel  160   n  on detection surface  141 , a first vertical row of four subdetectors whose subdetectors were previously situated to the right of middle macropixel  160   n  and deactivated, as well as a second vertical row of four subdetectors whose subdetectors were previously associated with right macropixel  160   n−1 , are associated with middle macropixel  160   n . In addition, on the left side of middle macropixel  160   n , two vertical rows of four subdetectors each, previously associated with first macropixel  160   n , are deactivated. 
     In contrast to the measuring arrangement in  FIGS. 3 through 5 , in which laterally adjacent sampling points directly adjoin one another, in the present exemplary embodiment the sampling points are spaced a small distance apart. This distance allows a sharper separation of the individual sampling points or the associated macropixels from one another. This distance may be smaller or larger, depending on the specific embodiment. When the scanning speed, the measuring rate, and the imaging properties of the optical components are coordinated with one another in such a way that the shift of the sampling points for directly successive individual measurements preferably corresponds exactly to the distance between the subdetectors on the detection surface or to an integral multiple of this distance, even sampling points without such a distance or with only a marginally small distance from one another may be implemented. Particularly high lateral image resolution may thus be achieved. 
     If the subdetectors have to be initially activated prior to each reception, it is meaningful for the grouping and activation of the subdetectors in question to take place in each case just before the reflected or backscattered single laser pulse strikes the detection surface. For subdetectors which may detect without a significant delay and which may thus operate quasi-continuously, the grouping of the subdetectors in question to form macropixels may optionally also take place during or even shortly after the particular individual measurement. 
     The basic design of the present invention is in accordance with conventional macro LIDAR scanners. However, whereas conventional scanners use a single detector for each vertical plane, in the scanner according to the present invention an arrangement of subdetectors that extends in the rotational plane, for example a subdetector row or a subdetector array (matrix-like arrangement of subdetectors), is used. The individual subdetectors of the subdetector system may be individually associated to form macrodetectors.  FIGS. 3 through 5  show by way of example the sequence of a measurement made up of a number of “N” single laser pulses. At the point in time of the first pulse emission, the subdetectors in dark crosshatch in  FIG. 3  are associated with a first macropixel  160   n . The imaging of the received single laser pulse is assumed to be centered on first macropixel  160   n . The imaging of the single laser pulse at a defined speed will move over the two-dimensional subdetector system as a function of the rotational speed of sensor head  101 . In  FIG. 4 , first macropixel  160   n  is depicted in dark crosshatch after a shift of exactly one subdetector, while the original position of first macropixel  160   n  is indicated by a circle depicted with a dotted line. If the macropixel is now divided as indicated, the spatial resolution for first macropixel  160   n  is maintained, while the pulse energy received from the subdetectors in light crosshatch, and thus also the measuring time for subsequent second macropixel  160   n+1 , are utilized. This approach thus allows multipulse measuring principles which, despite the continuous rotational movement, have the same lateral resolution as a single-pulse system. In particular, no pulse energy or measuring time is lost. The principle is basically applicable for biaxial as well as coaxial macroscanners. 
     Although the present invention has been described primarily with reference to specific exemplary embodiments, it is in no way limited thereto. Those skilled in the art will therefore appropriately modify the described features and combine them with one another without departing from the core of the present invention. In particular, the methods, in each case described separately herein, may also be arbitrarily combined with one another.