Patent Publication Number: US-2023154034-A1

Title: Vehicle measuring apparatus and operating method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority from Italian patent application no. 102021000029027 filed on Nov. 16, 2021, the entire disclosure of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     This invention relates to a vehicle measuring apparatus and the corresponding method of operation. In particular, this invention concerns the calibration and determination of the actual position of component parts, preferably image acquisition devices, of a vehicle measuring apparatus. 
     PRIOR ART 
     Vehicle measuring apparatuses are known that comprise a base unit resting on a plane, a support structure that is mounted on the base unit and is provided with a support bar that is approximately horizontal, and two side video cameras that are stably mounted on the opposite ends of the support bar to acquire images of a vehicle arranged in a service area. 
     The images acquired are generally provided to a control unit that processes them via the vehicle measuring algorithms to provide vehicle data regarding some vehicle devices/components/parts. For example, some vehicle measuring algorithms provide vehicle data regarding the arrangement of the vehicle wheels, and/or vehicle data that is useful for calibrating electronic devices of an electronic ADAS (Advanced Driver Assistance Systems) present on board the vehicle and/or vehicle data concerning the position of the vehicle measuring apparatus in relation to the vehicle to be measured. 
     To be able to operate correctly and ensure a certain precision of the measurement, the vehicle measuring apparatuses must be subject to procedures to calibrate the video cameras to compensate, on a case-by-case basis, for any variations/alterations of their position/orientation in relation to a condition established or detected previously, for example during an initial calibration or set-up step of the vehicle measuring apparatus. 
     In particular, during transport, and/or assembly, and/or use of the vehicle measuring apparatus, the two video cameras and the support bar are subject to collisions and/or thermal dilations that may cause not-insignificant variations of the position/orientation of the video cameras themselves in relation to the condition previously detected and stored in the vehicle measuring apparatus. These accidental alterations, if not detected with a certain precision, introduce errors that significantly affect the correctness of the vehicle data provided via the vehicle measuring methods mentioned above. To this end, the video cameras must, therefore, be subject to the above-mentioned calibration procedure. Some known calibration procedures involve: manually providing an operator with a calibration panel at a certain distance from the vehicle measuring apparatus before the video cameras themselves in different, pre-determined positions; simultaneously acquiring, via two video cameras, the image of the calibration panel in the various positions; processing the panel images to determine the relative positions of the two video cameras, one in relation to the other; and calibrating the two video cameras based on the relative positions determined. 
     The implementation of the calibration method for the video cameras described above has numerous technical problems. In particular, the manual intervention for calibration, as well as affecting, in a not insignificant way, the complexity, time, and, thus, cost of the calibration, significantly limits the frequency of execution and increases the risk of error in case of accidental alterations, subsequent to manual calibration. 
     DESCRIPTION OF THE INVENTION 
     The purpose of this invention is, thus, to provide a vehicle measuring apparatus that overcomes the above-mentioned technical issues. 
     In accordance with this purpose, according to this invention, a vehicle measuring apparatus is provided, as well as its method of operation, as defined in the related independent claims and, preferably, but not necessarily, in any one of the claims dependent thereon. 
     The claims describe preferred embodiments of this invention forming an integral part of this description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       This invention will now be described with reference to the attached drawings that illustrate a non-limiting embodiment thereof, in which: 
         FIG.  1    is a perspective view of a vehicle measuring apparatus arranged in a service area produced according to the precepts of this invention, 
         FIG.  2    is a front perspective view, with parts on an enlarged scale, of the vehicle measuring apparatus shown in  FIG.  1   , 
         FIG.  3    is lateral perspective view of the vehicle measuring apparatus shown in  FIG.  1   , 
         FIG.  4    is a raised front view of the vehicle measuring apparatus shown in  FIG.  1    with minimum dimensions, 
         FIG.  5    is a raised front view, with parts in cross-section and parts on an enlarged scale, of the vehicle measuring apparatus shown in  FIG.  1   , 
         FIGS.  6  and  7    are two perspective views on an enlarged scale of the two electronic modules of the vehicle measuring apparatus shown in  FIG.  1   , 
         FIGS.  8  and  9    are two perspective views of the vehicle measuring apparatus produced according to a first embodiment, 
         FIGS.  10  and  11    are two perspective views of the vehicle measuring apparatus produced according to a second embodiment, 
         FIG.  12    is a perspective view of the vehicle measuring apparatus produced according to a third embodiment, 
         FIG.  13    shows a plan view on an enlarged scale of the target of the vehicle measuring apparatus shown in  FIG.  12   . 
     
    
    
     PREFERRED EMBODIMENTS OF THE INVENTION 
     With reference to  FIGS.  1 - 7   , the reference number  1  indicates, as a whole, a vehicle measuring apparatus, such as vehicles, motor vehicles, or the like (vehicles with engines). 
     As will be described in more detail below, the vehicle measuring apparatus  1  may be configured so as to implement vehicle “measuring methods”. 
     The measuring methods may involve, as desired, the execution of one or more of the following measuring functions: functions to determine the arrangement of the vehicle  9  wheels, and/or functions to calibrate one or more electronic devices of an ADAS (acronym for Advanced Driver Assistance Systems) present on board of the vehicle  9 , and/or functions to determine the position of the vehicle measuring apparatus  1  in relation to the vehicle  9 , which is being measured. In the discussion that follows, “measuring method” will be understood to refer to a method that, when implemented by the vehicle measuring apparatus  1 , ensures that the latter performs one or more measuring functions mentioned above. 
     With reference to  FIG.  1   , the vehicle measuring apparatus  1  rests on a plane P opposite a vehicle  9  that is positioned, in turn, in a service area  8  adjacent to the vehicle measuring apparatus  1  and has a longitudinal axis K. 
     With reference to  FIGS.  1 - 7   , the vehicle measuring apparatus  1  comprises a resting platform or base unit  2 , which is arranged resting on the plane P and comprises a target  3  conveniently defining a reference or calibration target, which will be described in detail below. The base unit  2  may, preferably, be mobile on the plane P (in one or more directions) for example via wheels  2   a.    
     The vehicle measuring apparatus  1  comprises, in addition, a frame or support structure  4 , which is mechanically coupled to the base unit  2 . The vehicle measuring apparatus  1  comprises, in addition, a support bar  5 , which is mechanically coupled to the support structure  4 . The support bar  5  extends along a longitudinal axis A approximately horizontal above the base unit  2 . The support bar  5  may comprise, for example, a rod or cross member, and consist of a straight section made of rigid material, preferably metal, for example aluminium or the like, having a preferably quadrangular cross-section, and is sized so as to laterally extend the vehicle measuring apparatus  1  on both opposite sides. 
     With reference to  FIGS.  2 ,  5 - 7   , the vehicle measuring apparatus  1  comprises an electronic vehicle measuring system  6  that is configured so as to carry out one or more vehicle measuring methods. 
     According to one embodiment shown in the attached figures, the electronic vehicle measuring system  6  preferably comprises two main image acquisition devices  7 , which are stably mounted (fixed) on the two corresponding opposite ends  5   a  of the support bar  5  according to relative “poses”. In this description, the term “pose” of an image acquisition device refers to its position and the orientation of its image acquisition visual field. The pose of an image acquisition device may be “relative”, i.e., defined in relation to the pose of another image acquisition device, or it may be “absolute”, i.e., determined in relation to a common, pre-determined reference system. The “relative” pose of an image acquisition device in relation to another image acquisition device is indicative both of its position in relation to the position of the other image acquisition device and the orientation angle of its image acquisition visual field in relation to the orientation of the other image acquisition device. 
     The two main image acquisition devices  7  are stably fixed to the support bar  5  and are positioned on the same (one to the right and one to the left in  FIG.  5   ) so that the corresponding visual fields (indicated, for clarity, with the arrows W in  FIGS.  1  and  2   ) are oriented towards the service area  8  so as to acquire the images relating to the vehicle  9  and/or to component parts and/or additional parts mounted on the same (targets, wheels, or the like), indicated below as “vehicle images”. The two main image acquisition devices  7  are configured to provide, in the form of data and/or signals, the vehicle images. 
     With reference to  FIGS.  2  and  3   , the electronic vehicle measuring system  6  comprises, in addition, an electronic control system  10  that is operationally connected to the main image acquisition devices  7  so as to receive the vehicle images captured from them. The two main image acquisition devices  7  may be conveniently controlled by the electronic control system  10  according to a stereoscopic image acquisition method in which the acquisition of stereograms (simultaneous acquisition) is involved. 
     The electronic control system  10  is, in addition, configured so as to process the vehicle images via one or more measuring functions (algorithms) provided for by the measuring method implemented by the vehicle measuring apparatus  1 . 
     One measuring method implemented by the electronic vehicle measuring system  6  may comprise, for example, an ADAS calibration method for one or more electronic sensor devices comprised in an advanced driver assistance system (ADAS)  100  of the vehicle  9  ( FIG.  1   ). The electronic sensor devices may comprise any sensor  100   a  of an advanced driver assistance system  100  assembled in the vehicle  9 . For example, the sensor  100   a  may comprise: a radar sensor, an optical sensor, a video camera, a LIDAR sensor, an ultrasound sensor, an infrared sensor (IR), or any other similar sensor. 
     Alternatively, and/or additionally, the electronic vehicle measuring system  6  may be configured so as to implement a measuring method that is designed to determine the position of the vehicle measuring apparatus  1  in relation to the vehicle  9  (or vice versa). Alternatively, and/or additionally, the electronic vehicle measuring system  6  may also be configured so as to carry out/implement a measuring method to determine the arrangement of the wheels of the vehicle  9 . The method to determine the arrangement of the wheels of the vehicle  9 , the ADAS calibration method and the method to determine the position of the vehicle  9  are known measuring methods and, as a result, will not be described further. 
     The electronic vehicle measuring system  6  is provided, in addition, with two auxiliary image acquisition devices  11 , which are mounted on the support bar  5  at a predetermined distance from each other and in predetermined positions in relation to the two main image acquisition devices  7 . In the example illustrated in the attached figures, each of the auxiliary image acquisition devices  11  is arranged stably/rigidly on one end  5   a  of the support bar  5  in a position immediately adjacent (close) to a main image acquisition devices  7  (one to the right and one to the left in  FIG.  5   ). The relative pose of each auxiliary image acquisition device  11  in relation to the corresponding main image acquisition device  7  (adjacent), and/or vice versa, may be predetermined and contained/stored in a memory unit (not illustrated) of the electronic control system  10 . The relative pose of each auxiliary image acquisition device  11  in relation to the corresponding main image acquisition device  7 , and/or vice versa, may be determined and stored, for example in an initial calibration and/or production step of the vehicle measuring apparatus  1 . 
     The memory unit may also contain information concerning the position and/or distance of each end  5   a  of the support bar  5  in relation to the position of the adjacent main image acquisition device  7  present on the support bar  5  itself. 
     It is appropriate to specify that the relative and/or absolute “pose” of an image acquisition device (main  7  and/or auxiliary  11 ) may be determined by the electronic control system  10  via the implementation of one or more resolving computer vision algorithms, which are configured so as to resolve PnP (Perspective-n-Point) and/or EPnP (Efficient PnP), and/or SQPnP (described by Terzakis and Lourakis in the European conference publication on artificial vision (ECCV) 2020, 478-494), and/or RANSAC equation systems, or the like. 
     The auxiliary image acquisition devices  11  are arranged on the support bar  5  so that the corresponding visual fields (indicated with the arrows H in  FIGS.  1  and  2   ) are oriented towards the underlying base unit  2  (towards the bottom) so as to acquire images containing the target  3  of the base unit  2 , indicated below as “target images”. The two auxiliary image acquisition devices  11  are configured to provide, in the form of data and/or signals, the target images. 
     The electronic control system  10  is operationally connected to the auxiliary image acquisition devices  11  to receive the target images. The electronic control system  10  is also configured so as to determine, based on the target images received, the actual pose of each auxiliary image acquisition device  11  in relation to the target  3 . 
     The electronic control system  10  is also configured so as to determine the relative pose of each auxiliary image acquisition device  11  in relation to the other auxiliary image acquisition device  11  and/or the absolute pose, on the basis of the poses of the auxiliary image acquisition devices  11  determined in relation to the target  3 . 
     The technical effect obtained thanks to the combined use of the auxiliary image acquisition devices  11  and the target  3  present in the base unit  2 , is represented by the fact that the electronic control system  10  is designed to determine, with high precision, and completely automatically, the actual poses of the auxiliary image acquisition devices  11  in relation to the target  3 . The Applicant found that by positioning the target  3  on the base unit  2 , you obtain/define a convenient fixed reference in the vehicle measuring apparatus  1  that can be used to determine, with great precision, the actual poses of the two auxiliary image acquisition devices  11 . 
     The control system  10  is also, conveniently, configured in order to determine the pose of each main image acquisition device  7  based on the poses of the auxiliary image acquisition devices  11 . The pose of each main image acquisition device  7  in relation to the target  3  can be conveniently determined by the control system  10  by combining the information relating to its pose in relation to the corresponding auxiliary image acquisition device  11 , with the information relating to the pose of the auxiliary image acquisition device  11  itself, determined in relation to the target  3 . 
     The relative pose of each main image acquisition device  7  in relation to the other main image acquisition device  7  may be conveniently determined by the control system  10  by combining the information relating to the poses of the main image acquisition devices  7  determined in relation to the poses of the corresponding, adjacent auxiliary image acquisition devices  11 . 
     The technical effect obtained is that of being able to determine, completely automatically and in real time, the actual pose of the main image acquisition devices  7  as well. 
     The control system  10  is also configured so as to calibrate the main image acquisition devices  7  based on the related determined poses. The calibration of the main image acquisition devices  7  may involve the electronic control system  10  determining an offset between the actual poses of the main image acquisition devices  7  and the poses of the same stored during a previous calibration. The control system  10  may be configured so as to regulate or adjust, during calibration, one or more control parameters connected to the main image acquisition devices  7  based on the determined offset. 
     The technical effect obtained is that of ensuring that the vehicle measuring apparatus  1  carries out, completely automatically, the calibration (self-calibration) of the main image acquisition devices  7 . 
     It remains understood that the control system  10  may be configured so as to carry out, in addition to or alternatively to, a calibration of the auxiliary image acquisition devices  11  of the whole that is similar to that described above implemented in the main image acquisition devices  7 . 
     The electronic control system  10  may also be configured so as to conveniently determine the position of each of the two ends  5   a  of the support bar  5  based on the (relative or absolute) poses of the two main image acquisition devices  7 , and/or based on the (relative or absolute) poses of the two auxiliary image acquisition devices  11 . 
     The electronic control system  10  may also be conveniently configured to conveniently detect/determine a deformation of the support bar  5  based on the poses of the auxiliary image acquisition devices  11  and/or based on the position of each of the two ends  5   a  of the support bar  5 . 
     The technical effect obtained is that of detecting, in real time, deformation of the support bar  5  caused by collisions and/or thermal expansions. The deformation may be determined based on offsets of the ends  5   a  in relation to a predetermined condition. Having determined the deformation of the support bar  5  and, thus, the relative offsets, the electronic control system  10  may, conveniently, be designed to selectively carry out an automatic calibration of the devices of the vehicle measuring apparatus  1  such as: the main image acquisition devices  7 , and/or the auxiliary image acquisition devices  11 , and/or the calibration devices  15  and  16 . 
     The electronic control system  10  may also be configured so as to conveniently determine the position of the support bar  5  in relation to the target  3  or to the base unit  2 , based on the positions of its two ends  5   a.    
     An additional technical effect obtained is that of being designed to determine, completely automatically, any variations in size or shape of the support bar  5   a.    
     An additional technical effect obtained is that of being able to determine, moment by moment, the position of the support bar  5  in relation to the target  3 , i.e., the base unit  2 . As will be explained in detail in the discussion that follows, the determination of the position of the support bar  5 , in real time, makes it possible to automatically determine, indirectly, the position of other devices present in the vehicle measuring apparatus  1  too and used in the measuring methods. 
     According to this invention, the electronic control system  10  may be configured so as to determine and store, completely automatically, in the memory unit, repeatedly, for example at predetermined intervals, the poses and/or calibration of the auxiliary image acquisition devices  11 , and/or the poses and/or the calibration of the main image acquisition devices  7 , and/or the positions of the ends  5   a , and/or the position of the support bar  5 . 
     The technical effect is that of strongly reducing the risk of error caused by any alterations of the poses of the main image acquisition devices  7  and/or the auxiliary  11  ones, and/or by alterations in the size or shape of the support bar  5 . 
     With reference to the embodiment shown in  FIGS.  1  to  7   , the base unit  2  may conveniently comprise at least one two-dimensional target  3 . The target  3  may conveniently comprise at least one two-dimensional image (quadrangular, for example rectangular) that represents a predetermined pattern. In the example illustrated, in  FIGS.  1 - 5   , the pattern has a shape containing graphic elements. In the embodiment shown in  FIGS.  1 - 5   , the graphic elements may be depicted on a flat surface having a neutral-coloured background, preferably a white background. 
     In the example illustrated in  FIGS.  1 - 5   , the target  3  is made on a panel  3   a . The panel  3   a  is coupled to the body of the base unit  2  in a position so as to ensure that the image of the target  3  can be observed simultaneously from the two auxiliary image acquisition devices  11 . The panel  3   a  preferably lies on a plane that is approximately horizontal. The panel  3   a  is preferably arranged on the upper surface of the base unit  2  so as to be positioned below the support bar  5 , preferably below a central portion  5   b  of the same. The panel  3   a  may consist of, for example, a quadrangular slab or lamina, preferably rectangular, based on stiff material, for example metal. The two-dimensional target  3  is made on the upper face of the panel  3   a , opposite the plane  3 . 
     With reference to  FIGS.  5 ,  6 , and  7   , the main image acquisition devices  7  and the auxiliary  11  ones may comprise video or photographic cameras. It remains understood that the video or photographic cameras may comprise digital video or photographic cameras operating to acquire images in the range of the whole electromagnetic spectrum or, alternatively or additionally, selectively within a predetermined range of the electromagnetic spectrum (for example, the infrared spectrum). The angular orientation of the visual field connected to the pose of an image acquisition device (auxiliary  11  or main  7 ) may indicate, for example, the angular orientation of the optical axis of the video camera in relation to the target  3 . 
     According to the preferred embodiment shown in  FIG.  5   , the main image acquisition devices  7  and the auxiliary  11  ones are conveniently integrated/arranged rigidly/stably in the same electronic image acquisition equipment  12  mounted on the end  5   a  of the support bar  5 . The electronic image acquisition equipment  12  may comprise, for example, an external protective casing  12   a  made of stiff material (for example polymer) with an approximately box-shaped form that is rigidly/stably fixed to the end  5   a  of the support bar  5  and permanently/stably houses, inside, a main image acquisition device  7  and an auxiliary image acquisition device  11 . 
     The technical effect of the integration of the main image acquisition devices  7  and the auxiliary  11  ones in a single module is that of ensuring the maintenance of the relative pose between the same and to thus increase the robustness of the precision both during the calibration and during the determination of the positions. 
     According to a possible embodiment illustrated in  FIG.  5   , the main image acquisition device  7  may comprise an electronic board  7   a  (with circuits and electronic components) that is stably installed (fixed) inside the external casing  12   a  and supports an optoelectronic module  7   b . The optoelectronic module  7   b  may comprise, for example, an optical group and may be installed on the electronic board  7   a  so as to face a through hole made on a vertical wall of the external casing  12   a . The optical assembly may be installed so that its visual field is oriented towards the vehicle  9 . 
     According to the embodiment illustrated in  FIG.  5   , the auxiliary image acquisition device  11  comprises an electronic board  11   a  (with circuits and electronic components) stably installed in the external casing  12   a  below the electronic board  7   a  and supports an optoelectronic module  11   b  facing a side opening  12   b  of the external casing  12   a  facing the base unit  2 . The optoelectronic module  11   b  may comprise an optical assembly that is preferably installed on the electronic board so that its visual field is oriented towards the underlying target  3 . 
     According to a preferred embodiment shown in  FIGS.  1 - 5   , the vehicle measuring apparatus  1  also comprises a support column  14  that extends cantilevered from the base unit  2  above the same along a vertical axis B. The support column  14  may be mechanically coupled to the base unit  2  so as to rotate around the axis B in relation to the base unit  2  itself. The rotation of the support column  14  around the axis B may be carried out via an electromechanical assembly (actuators, and/or electric motors) (not illustrated) based on controls provided by the electronic control system  10 . 
     With reference to  FIGS.  1 - 5   , the support structure  4  may be mounted on the support column  14 . The support structure  4  is mounted on the support column  14  so as to shift vertically along the axis B, from and towards the base unit  2 . The vertical movement of the support structure  4  may be carried out via electromechanical components (actuators, and/or electric motors) (not illustrated) based on controls provided by the electronic control system  10 . 
     The support structure  4  is also mechanically coupled to the support column  14  so that the rotation of the latter around the axis B determines a corresponding rotation of the support structure  4  around the axis B itself. In the example illustrated, the above-mentioned vertical and/or rotary movement of the support structure  4  determines the same vertical, and respectively rotary, movement of the support bar  5  in relation to the base unit  2 , and, thus, in relation to the target  3  (along and around the axis B). 
     The support bar  5  may also be coupled to the support structure  4  so as to axially translate along the axis A, staying horizontal, so as to vary the position of the related ends  5   a  in relation to the base unit  2  and, thus, to the target  3 . The support bar  5  may be moved along the axis A via an electromechanical assembly (actuators, and/or electric motors) (not illustrated) based on controls imparted by the electronic control system  10 . 
     According to one embodiment shown in  FIGS.  1 - 5   , one of the calibration devices of the vehicle measuring system  6 , indicated with  15  in  FIGS.  1 - 5   , comprises a target panel that is designed for calibrating one or more sensors  100   a  consisting of the ADAS video cameras of the vehicle  9 . According to one embodiment, the target panel of the calibration device  15  may comprise a monitor/display (flat, LCD, or OLED screen or the like) designed, in use, to display, on command, a digital image of an ADAS calibration target that depends on the optical ADAS sensor to be calibrated. 
     According to the preferred embodiment shown in  FIGS.  1 - 5   , the calibration device  15  is stably coupled to the support structure  4  so that its vertical movement along the axis B, and/or its rotation around the axis B, is caused by the vertical movement, and, respectively, by the rotation of the support structure  4  along and around the axis B itself. The vertical and/or rotary movement of the calibration device  15  may, thus, be selectively controlled by the control system  10  via the control of the electromechanical components (actuators, and/or electric motors) that selectively control the rotation of the column  14  and/or the vertical movement of the support structure  4 . 
     The control system  10  may be conveniently configured so as to control/determine, moment by moment, or in real time, the position of the calibration device  15  based on the positions of the ends  5   a  of the support bar  5  determined in relation to the target  3 . The support bar  5  and the calibration device  15  are, in fact, mechanically coupled to the support structure  4  so as to carry out the same movements. Therefore, determining moment by moment the position of the ends  5   a  of the support bar  5 , it is possible to conveniently determine the position of the calibration device  15  in relation to the target  3 . 
     The technical effect is that of being able to control, automatically, and moment by moment, the position of the calibration device  15  without the aid of sensors and/or complex and costly mechanisms, such as encoders, resolvers, or the like, but just using the above-mentioned auxiliary image acquisition devices  11 . 
     An additional technical effect consists in the fact of being able to know/immediately obtain, upon the start-up/switching-on of the vehicle measuring apparatus  1 , the position of the calibration device  15  based on the target images provided by the auxiliary image acquisition devices  11  (auto-zero). 
     One of the calibration devices, identified with  16  in the  FIGS.  1 - 5   , comprises a radar panel designed for calibrating the ADAS radar sensors. The radar panel is coupled to the support bar  5 . In particular, the radar panel is coupled to the support bar  5  in an axially fixed position. 
     The control system  10  may be conveniently configured so as to control/determine, moment by moment, or in real time, the position of the calibration device  16  based on the positions of the ends  5   a  of the support bar  5 . 
     The technical effect is that of being designed to control, automatically and moment by moment, the horizontal position of the calibration device  16  as well, without the aid of sensors and/or mechanisms, such as encoders, resolvers, or the like, but just using the auxiliary image acquisition devices  11 . 
     An additional technical effect consists in the fact of being able to know/immediately obtain, upon the start-up/switching-on of the vehicle measuring apparatus  1 , the position of the calibration device  16  as well, based on the target images provided by the auxiliary image acquisition devices  11 . 
     According to the preferred embodiment shown in  FIG.  1   , the electronic control system  10  may comprise at least one computer. The computer may preferably be a tablet computer or any similar computer device. The computer may preferably be operationally connected to the electromechanical components mentioned above (actuators, and/or electric motors) and/or with image acquisition devices  7  and  11  so as to be designed to carry out, with the same, a two-way communication of the data/signals, preferably a wireless communication. 
     With reference to  FIG.  4   , the support bar  5  may comprise two connection mechanisms  18 , for example hinges, that connect the two opposite ends of the central portion  5   b  of the support bar  5  to the corresponding side portions of the support bar  5  itself that support the image acquisition devices  7  and  11 . The connection mechanisms  18  are each structured to enable a lateral portion of the support bar  5  to rotate between an operating position ( FIG.  1   ) wherein the side portion is horizontal (coaxial to the axis A) and aligned (parallel) to the central portion  5   b , and a rest position ( FIG.  4   ) (minimum dimensions) in which the side portion of the support bar  5  is arranged orthogonal to the (vertical) axis A so as to be positioned approximately to the side of the vertical side of the calibration device  15 . The technical effect obtained is that of enabling the reduction of the lateral bulk of the support bar  5  in the vehicle measuring apparatus  1  when it is not operating. 
     It is understood that this invention is not limited to the use of the main image acquisition devices  7 , but may also involve a vehicle measuring apparatus  1  that, alternatively, may not have the main image acquisition devices  7  mentioned above. 
     With reference to  FIG.  1   , the method of operation of the vehicle measuring apparatus  1  will be described below in which it is imagined, for the purpose of improving the clarity of this description, that the memory unit of the electronic control system  10  contains: the poses of the auxiliary image acquisition devices  11 , preferably the poses of the main image acquisition devices  7  (if present), the position of the support bar  5 , and/or of its ends  5   a , the position of the calibration devices  15  and  16 . It is understood that the poses and/or positions may be stored in the memory unit (in relation to a common reference system) during a step prior to implementing the method described below. This previous step may correspond, for example, to a production step wherein the configuration and/or set-up of the apparatus was carried out, and/or a calibration step and/or a previous calibration step. 
     Initially, a step is provided for positioning the vehicle measuring apparatus  1  before the vehicle  9  and for rotating (when the vehicle measuring apparatus is provided with the mechanisms  18 ) the two side portions of the support bar  5  downwards from the rest position ( FIG.  4   ) to the operation position ( FIG.  1   ). 
     Following the action of the vehicle measuring apparatus  1 , the method of operation involves implementing the following steps: capturing the target images via the auxiliary image acquisition devices  11 , and processing the target images to determine and store at least the actual poses of the auxiliary image acquisition devices  11  in relation to the target  3  (base unit  2 ). 
     The method of operation may also comprise the step of processing the target images to determine and store the actual poses of the main image acquisition devices  7  based on the actual poses of the auxiliary image acquisition devices  11  determined in relation to the target  3 . 
     The method of operation may also comprise the step of determining the offset/error between the actual pose determined of each main image acquisition device  7  and its pose previously stored in the memory unit. In this step, the method of operation may comprise the step of implementing the procedures for correcting the position/orientation of the main image acquisition devices  7  based on the determined offset. In other words, the method of operation may comprise the step of calibrating the main image acquisition devices  7  based on the actual poses determined by the processing of the target images. 
     The method of operation may also comprise, alternatively and/or additionally, the step of automatically calibrating the auxiliary image acquisition devices  11  based on the related poses actually determined. For example, this step may be included when the vehicle measuring apparatus  1  does not have the main image acquisition devices  7 . 
     In this step, the method of operation may comprise the step of determining the offset/error between the actual, determined pose of the auxiliary acquisition device  11  and its pose previously stored in the memory unit. In this step, the method of operation may comprise the step of implementing procedures for correcting the position/orientation of the auxiliary image acquisition devices  11  based on the determined offset. 
     The method of operation may also comprise the step of determining, in response to control signals provided by the electronic control system  10 , the position of the ends  5   a  of the support bar  5  based on the actual poses of the auxiliary image acquisition devices  11 . Conveniently, the position of the ends  5   a  of the support bar  5  may be determined during the handling of the support bar  5  itself, so as to selectively control its vertical movement (along the axis B), the rotary movement (around the axis B), and the axial movement (along the axis A). 
     The method of operation may also be conveniently configured so as to conveniently detect/determine a deformation of the support bar  5  based on the poses of the auxiliary image acquisition devices  11  and/or based on the position of each of the two ends  5   a  of the support bar  5 . 
     The method is designed to selectively carry out automatic calibration of the devices of the vehicle measuring apparatus  1  based on the deformation of the support bar  5 . The automatic calibration may, preferably, be carried out on at least the following devices: the main image acquisition devices  7 , and/or the auxiliary image acquisition devices  11 , and/or the calibration devices  15  and  16 . 
     The method of operation may also comprise the step of determining, in response to control signals provided by the electronic control system  10 , the position of the calibration devices  15  and/or  16  based on the positions of the ends  5   a  of the support bar  5 . Conveniently, the position of the calibration devices  15  and/or  16  may be determined during the handling of the same so as to selectively control its movements. 
     The vehicle measuring apparatus  1  makes it possible to maintain control of the relative pose and/or the absolute pose of the two main image acquisition devices  7  and/or auxiliary  11  ones used by the measuring methods described above. Therefore, any time the position and/or orientation of the two main image acquisition devices  7  is subject to a change, for example an accidental one or following the re-positioning of the side portions hinged to the support bar  5  in the operating position, the vehicle measuring apparatus is designed to measure this change with great precision without requiring operator interventions. 
     In addition, the vehicle measuring apparatus is designed to determine, with precision, the positions of the other devices mounted on the support structure too, such as, for example the calibration devices  15  and  16  used for ADAS calibration, eliminating, in this method, the need to use other position sensors, thus reducing the complexity and costs of the vehicle measuring apparatus itself. 
     In addition, the vehicle measuring apparatus is designed to determine, with precision, the position of the support bar  5  too and of its two ends  5   a  during the direct and/or indirect movement of the same. 
     Finally, it is clear that the apparatus and method described above may be altered, or variations may be produced thereof, without, as a result, departing from the scope of this invention. 
     The embodiment shown in  FIGS.  8  and  9    relates to a vehicle measuring apparatus  200 , which is similar to the vehicle measuring apparatus  1  shown in  FIGS.  1 - 7   , and whose component parts will be identified, where possible, with the same reference numbers that identify corresponding parts of the vehicle measuring apparatus  1 . The vehicle measuring apparatus  200  differs from the first vehicle measuring apparatus  1  in that the base unit  2  preferably comprises, centrally, a vertical target  203 . The vertical target  203  comprises two opposite faces, each of which has a two-dimensional image oriented so as to be captured by a corresponding auxiliary image acquisition device  11 . 
     The embodiment shown in  FIGS.  10  and  11    relates to a vehicle measuring apparatus  300 , which is similar to the vehicle measuring apparatus  1  shown in  FIGS.  1 - 7   , and whose component parts will be identified, where possible, with the same reference numbers that identify corresponding parts of the vehicle measuring apparatus  1 . The vehicle measuring apparatus  300  differs from the first vehicle measuring apparatus  1  in that the base unit  2  comprises two, lateral targets  303 . The two targets  303  are arranged on opposite sides in relation to the column  14  and at a certain distance from each other. The two targets  303  each comprise a flat upper face slightly inclined in relation to a flat horizontal plane on which there is a two-dimensional image oriented so as to be captured by a corresponding auxiliary image acquisition device  11 . 
     The embodiment shown in  FIGS.  12  and  13    relates to a vehicle measuring apparatus  400 , which is similar to the vehicle measuring apparatus  1  shown in  FIGS.  1 - 7   , and whose component parts will be identified, where possible, with the same reference numbers that identify corresponding parts of the vehicle measuring apparatus  1 . The vehicle measuring apparatus  400  differs from the vehicle measuring apparatus  1  in that the base unit  2  comprises a three-dimensional target  403 . The three-dimensional target  403  comprises three reference elements  403   a  that extend cantilevered from the front side of the base unit  2  below the support bar  5 . The three reference elements  403   a  are approximately horizontal and extend parallel and spaced apart from each other so as to have the corresponding ends in three different positions, i.e., at three different distances in relation to the front side of the base unit  2 . Each reference element  403   a  comprises a rod on the free end of which there is a spherical body. In use, the auxiliary image acquisition devices  11  acquire the images of the three-dimensional target  403 , and the electronic control system  10  determines the three absolute reference points connected to the three ends of the three reference elements. The three absolute reference points enable the electronic control system  10  to determine, via the implementation of computer vision functions and/or algorithms the pose of the auxiliary image acquisition devices  11  in relation to the target  403   a.    
     It remains understood that according to a possible embodiment the body of the base unit  2  can be shaped so as to form a two-dimensional or three-dimensional target  3 . In other words, the base unit  2  can directly form the target  3  defining the reference point that can be observed from the auxiliary image acquisition devices  11 .