Abstract:
The present embodiments relate to a device for the non-destructive ultrasound testing of workpieces. The device comprises an ultrasonic test probe with an ultrasonic transducer, the ultrasonic test probe being configured for generating and coupling ultrasonic signals into a workpiece or/and for receiving ultrasonic signals from the workpiece. Furthermore, an electronic control unit is provided. The ease of operation is improved as a whole by a special configuration of the test probe and the control unit. Furthermore, the embodiments relate to a method for the non-destructive ultrasound testing of workpieces.

Description:
BACKGROUND 
       [0001]    Embodiments relate to a device for the non-destructive ultrasound testing of workpieces, in particular an ultrasonic test probe on which an input unit is disposed that is configured for transmitting control commands from a user to an electronic control unit. 
         [0002]    The use of pulsed ultrasonic signals for the non-destructive testing of workpieces has been known for years from a variety of methods in material testing. Generally, an ultrasonic test probe is coupled to the test piece using a couplant, generally water or gel. The ultrasonic test probe comprises an ultrasonic transducer that is suitable for generating ultrasonic signals and transmit them into the workpiece to be tested. They are at least partially reflected both on the boundary surfaces of the workpiece and on internal defects (e.g. cracks, pipes, inhomogeneities in the material, etc.) and can be detected by an ultrasonic transducer working as a receiver. In the pulse-echo method, the ultrasonic transducer is suitable to be used both as a transmitter as well as a receiver. In inspections according to the transsonification principle, a second ultrasonic transducer serves as a receiver disposed on the workpiece to be tested at a distance from the first ultrasonic transducer. The ultrasonic test probe is selected depending on the geometry, the other properties of the workpiece to be inspected and the testing task. 
         [0003]    The inspected testing region can be changed both by mechanical movement and the arrangement of ultrasonic test probes as well as by changing the ultrasound parameters of the ultrasonic signals coupled into the workpiece, if phased-array test probes with phase-accurately controllable transducer segments are used. 
         [0004]    The receiver converts the received ultrasonic signals into electrical signals. The electrical signals are then processed, for example amplified or/and filtered, and can be displayed by means of an imaging unit. The sound propagation of the coupled-in ultrasonic signals in the workpiece depends on the material and the ultrasound parameters, such as transmission/reception aperture, insonification angle and focusing depth of the transmitted ultrasonic signals in the workpiece. Depending on what the ultrasonic signals are reflected by, for example by a boundary surface of the workpiece or a flaw within the workpiece (pipe, inhomogeneity in the material, crack), the received ultrasonic signals differ from each other. The position of a flaw can be determined from the transit-time difference between the transmission of the ultrasonic signals and the reception of the reflected ultrasonic signals. The amplitude of the received ultrasonic signals permits drawing conclusions as to the size and the type of the detected flaw. Furthermore, the received ultrasonic signals depend heavily on the orientation and the distance of the flaw relative to the ultrasonic test probe. 
         [0005]    In order to be able to give as comprehensive an evaluation as possible of the workpiece to be tested, it may be beneficial if it is possible to process the received ultrasonic signals, for example by the possibility of changing their graphical representation or by amplifying or filtering the received ultrasonic signals. Furthermore, it may be beneficial to perform several inspections with different ultrasound parameters. In most cases, reacting to deviating geometries or other difficulties on-site is troublesome and time-consuming. Possibly, the different ultrasonic test probes have to be attached to the workpiece in order to obtain an optimum result. 
         [0006]    DE 102007015746 A1 discloses a device for the non-destructive ultrasound testing with a control unit configured as a “stand-alone” ultrasonic testing device, which is configured for communication with the ultrasonic transducer, is able to graphically display received ultrasonic signals, and has various operating elements. With the operating elements of the ultrasonic testing device, both the ultrasound parameters can be varied and the received ultrasonic signals processed. Depending on the workpiece to be inspected and the local conditions, handling of such a “stand-alone” ultrasonic testing device may be disadvantageous. Usually, it is necessary for the ultrasonic test probe to be guided by a user on the workpiece to be tested. Thus, having to execute inputs on an ultrasonic testing device using the other hand is inconvenient. 
         [0007]    Embodiments are based on the object of providing a device and a method for the non-destructive ultrasound testing of workpieces that are easier for a user to handle. 
         [0008]    This object is achieved by means of a device and a method as disclosed herein. Other advantages and features are apparent the exemplary embodiments described below, which are to be understood as illustrative, and not as limiting. 
       BRIEF DESCRIPTION 
       [0009]    A device according to the embodiments for the non-destructive ultrasound testing of workpieces comprises an ultrasonic test probe with an ultrasonic transducer. The ultrasonic test probe is configured for generating and coupling ultrasonic signals into a workpiece as well as, optionally, for receiving ultrasonic signals from the workpiece. Within the context of the present application, ultrasonic signals are to be understood to be ultrasonic fields that are emitted in pulsed form. For example, an ultrasonic test probe is used in the pulse-echo method for transmitting/receiving ultrasonic signals, or two ultrasonic test probes are used in the transsonification method, with one of the ultrasonic test probes respectively receiving the emitted signals of the other ultrasonic test probe. 
         [0010]    Further, the device according to the embodiments comprises an electronic control unit and an input unit, which is disposed on the ultrasonic test probe and configured for communication with the electronic control unit. The electronic control unit is to be understood as a higher-level control unit that can include the various sub-units, for example for beam control or evaluation. The sub-units that are optionally provided do not necessarily have to be united in a single device. 
         [0011]    Within the sense of the application, the term “communication” is to be interpreted broadly. For example, various kinds of data or/and signal transmission, in particular, are included which may take place both via cables as well as wirelessly, for example via WiFi, Bluetooth or infrared or other wireless or cable-based types of transmission. Moreover, communication within the sense of the application is to be considered the wireless or cable-based transmission of binary or analog standard signals and the transmission of digitally encoded data packets via bus systems or digital interfaces. 
         [0012]    According to the embodiments, control commands issued by the user by means of the input unit are transmitted to the electronic control unit. 
         [0013]    In an embodiment, the input unit comprises at least one mechanical operating element via which the user is able to issue control commands. They are issued, for example, by changing one or more of the following input parameters: actuating force, angle of rotation, deflection angle or contact position, or by a change over time of the aforementioned parameters. In an embodiment, the mechanical operating element has a rest position, relative to which changes of an input parameter are detected. Particularly, the mechanical operating element comprises a key, a switch, a joystick, a rotary knob or a ball. For example, the mechanical operating element comprises a joystick with an operating lever configured in such a way that the operating lever is pivotable in at least one plane. A deflection of the operating lever relative to its rest position can be detected as a change of a deflection angle relative to the rest position and processed by the input unit as a control command by the user. 
         [0014]    Moreover, the input unit can be configured in such a way that it detects control commands from a user in the form of voice inputs or by gesture control. For example, the input unit detects control commands from a user in the form of voice inputs. The voice input “Send Pulse” is detected, interpreted and transmitted in the form of a control command to the transmitting/receiving unit by the input unit. Thereupon, the control unit controls the ultrasonic transducer in such a way that the latter emits ultrasonic signals into the workpiece. 
         [0015]    In an embodiment, the electronic control unit is configured for generating a snapshot of the received ultrasonic signals in response to a control command from the user. For example, the received ultrasonic signals are graphically displayed by means of an imaging unit, and the control command from the user received via the input unit causes a screenshot of the display or/and the storing of the received ultrasonic signals in a certain file format, such as .txt, .asc or any other suitable format. 
         [0016]    In an embodiment, the electronic control unit comprises a transmitting/receiving unit configured for communication with the ultrasonic transducer for the purpose of transmitting or/and receiving ultrasonic signals. Particularly, the transmitting/receiving unit is configured for communication with the input unit. 
         [0017]    In an embodiment, the electronic control unit comprises an evaluation unit that is suitable for further processing received ultrasonic signals. For example, these can be displayed in different ways by means of an imaging unit. The evaluation unit is configured for communication with the transmitting/receiving unit. 
         [0018]    The ultrasonic test probe comprises a housing in which the ultrasonic transducer is disposed. In a development, the transmitting/receiving unit is also disposed in the housing of the ultrasonic test probe. 
         [0019]    In an embodiment, the ultrasonic transducer comprises at least two individually controllable segments that can be controlled in a phase-accurate manner by the transmitting/receiving unit, that is, ultrasonic test probes of the phased-array type are used with preference. In particular, linear arrays of 2D arrays can be used. Thus, different ultrasound parameters can be changed. For example, the transmission or/and reception aperture or/and the insonification angle or/and the transverse angle or/and the focusing depth of the ultrasonic signals in the workpiece or/and the central insonification point of the ultrasonic signals can be specifically influenced. The central insonification point means the point of intersection of the acoustic axis of the ultrasonic field and the workpiece surface. In particular in the case of phased arrays, this can vary depending on the transmission aperture used or the insonification angle without the test probe being moved mechanically. 
         [0020]    The term “insonification angle” designates the angle between the surface normal on the workpiece surface in the insonification point and the acoustic axis of the ultrasonic field in the workpiece. The acoustic axis and the surface normal together span the insonification plane E. A gradual change of the insonification angle results in a pivoting of the angle, a so-called “sector scan”. 
         [0021]    The term “transverse angle” within the context of the present application designates the angle of pivoting of the acoustic axis from the undisturbed insonification plane E, with the insonification angle remaining constant. Such a transverse pivoting is possible, for example, by means of a transmitting test probe having a two-dimensional array of individually controllable transducer segments. 
         [0022]    In an embodiment, the change of an ultrasound parameter from a starting parameter towards an end parameter takes place in discrete steps. This is supposed also to include the change of the ultrasound parameter in a single step. The starting parameters of the ultrasonic signal can be predefined by a user prior to a testing sequence. For example, the control commands from a user inputted by means of the input unit state that the insonification angle is to be changed from 20° to 40°. In the case of the discrete change, a first pulse sequence of ultrasonic signals will be transmitted at an insonification angle of 20° (starting parameter) by the ultrasonic transducer into the workpiece, and the next pulse sequence of ultrasonic signals at an insonification angle of 40° (end parameter). In the case of the gradual change, pulse sequences of ultrasonic signals with different insonification angles between 20° and 40° will be transmitted, in each case consecutively, into the workpiece. 
         [0023]    In an embodiment, the size or/and the number of steps for changing the ultrasound parameter can be varied via the input unit by means of control commands from a user. Particularly, for changing the size or/and the number of steps for changing an ultrasound parameter, the same control commands apply for all ultrasound parameters, for example the voice commands “up”, “down”, for increasing/reducing the size or/and number of steps. Furthermore, in a development, the ultrasound parameter whose size or/and number of steps for changing the respective ultrasound parameter is increased or reduced can be selected via another control command, for example by means of a mechanical operating element of the input unit. 
         [0024]    In an embodiment, the transmitting/receiving unit is configured for carrying out a “freeze” of the currently set ultrasound parameters in response to a control command from a user received via the input unit. Within the sense of the application, “freeze” means that the currently set ultrasound parameters are stored. In an embodiment, they are then used as new starting parameters for further changes. For example, a “freeze” takes place by actuating a key disposed on the ultrasonic test probe. 
         [0025]    In a first embodiment, the electronic control unit comprises a transmitting/receiving unit for the purpose of transmitting or/and receiving ultrasonic signals, and the control commands from a user issued via an input unit are converted by the transmitting/receiving unit for beam control. 
         [0026]    In a second embodiment, the electronic control unit comprises a graphical user interface (GUI) with a cursor. The control commands from a user issued by means of the input unit serve for navigating the cursor over a graphical user interface. For example, the cursor is navigated across the graphical user interface by means of a joystick disposed on the ultrasonic test probe, or by voice inputs such as “left, right, . . . ”. 
         [0027]    In an embodiment, the device is configured in such a way that the two embodiments can exist at the same time, and that it is possible to switch between the two modes for example by means of a switch of the input unit and/or a corresponding operating element in the GUI. 
         [0028]    The two embodiments are to be explained below with reference to an exemplary input unit with a mechanical operating element. The control commands from a user are in that case issued, for example, by changing one or more of the following input parameters: actuating force, angle of rotation, deflection angle or contact position. Their change over time may also constitute a control command. However, the person skilled in the art should not have any difficulties in transferring the principle onto differently configured mechanical input units. 
         [0029]    According to a first embodiment, the change of an input parameter by a user is converted by the transmitting/receiving unit into a change of ultrasound parameters. In an embodiment, the transmission or/and reception aperture, the insonification angle, the central insonification point or/and the focusing depth of the ultrasonic signals in the workpiece are changed. This list is not to be considered complete. 
         [0030]    In an embodiment, only one ultrasound parameter is changed at a time by a user changing an input parameter, with the other ultrasound parameters remaining constant. In particular, the ultrasound parameter that is to be changed can be determined by means of the input unit through an input on the GUI. 
         [0031]    For example, the mechanical operating element comprises a joystick with an operating lever configured in such a way that it is pivotable in two planes that are perpendicular to each other. A deflection of the joystick relative to its rest position can be detected as a change of a deflection angle relative to the rest position and as a control command by the user from the input unit. The control command is transmitted to the transmitting/receiving unit of the electronic control unit and used for the control of the ultrasonic test probe. 
         [0032]    For example, the change of the deflection angle of the joystick is converted, for example, into a change of the insonification angle of the ultrasonic signal of a phased-array test probe. Pivoting in a plane results in a change of the central angle formed by the ultrasonic field incident upon the workpiece surface with the normal on the workpiece surface. Pivoting the operating lever in another plane changes the transverse angle, with the insonification angle remaining constant. 
         [0033]    The change of an input parameter can be converted into a change of an ultrasound parameter by means of a conversion factor, there being respectively associated conversion factors for the various ultrasound parameters and input parameters. In an embodiment, a conversion factor can be respectively increased or reduced by a certain value (+2, +4, +. . . ) or factor (×2, ×4, × . . . ). 
         [0034]    For all conversion factors, the same control commands apply for changing them, for example the voice commands “up”, “down” for increasing/reducing the conversion factor. Particularly, it is possible to choose via another control command which conversion factor is changed. For example, the variation of the conversion factor takes place via a mechanical operating element of the input unit. For example, the mechanical operating element comprises a key, and the change of the conversion factor takes place by the user actuating the key. In an embodiment, the mechanical operating element comprises two keys, a +key and a −key, wherein an actuation of the +key respectively increases the conversion factor by a certain factor or certain value. In an embodiment, the keys apply for the conversion factors of all ultrasound parameters, and the user is able to choose in a suitable manner which conversion factor is changed. The selection can take place, for example, through a mechanical operating element of the input unit. 
         [0035]    According to the second embodiment, a change of an input parameter, for example of a deflection angle, an angle of rotation, an actuating force or a contact position, is used for navigating a cursor over the graphical user interface of the electronic control unit. In an embodiment, the rest position of the mechanical operating element corresponds to the resting position of the cursor within the graphical user interface, and the change of an input parameter results in a movement of the cursor. For example, the movement of an operating element configured as a ball causes a movement of the cursor in two directions in space on the graphical user interface. 
         [0036]    In an embodiment, the electronic control unit comprises an evaluation unit. The evaluation unit is configured for communication with the transmitting/receiving unit, and for processing received ultrasonic signals. For example, received ultrasonic signals can be amplified or filtered. 
         [0037]    In an embodiment, the graphical user interface is configured to generate different displays of the received ultrasonic signals and to display them on an imaging unit, for example as an A-scan, B-scan or as a sector scan. The effects on the received ultrasonic signal of changing ultrasound parameters can thus be observed in situ. 
         [0038]    In an embodiment, the transmitting/receiving unit can be controlled for the purpose of beam control via the graphical user interface of the evaluation unit. Particularly, this is done through buttons on the GUI that can be activated by means of the cursor. Within the sense of the application, the term buttons is to be interpreted broadly and comprises, for example, pull-down menus, entry fields, virtual keys, etc. 
         [0039]    In an embodiment, the transmission or/and reception aperture, the insonification angle, the transverse angle, the central insonification point or/and the focusing depth of the ultrasonic signals in the workpiece can be changed via buttons of the graphical user interface. This list is not to be considered complete. 
         [0040]    In an embodiment, the graphical user interface moreover has buttons for changing conversion factors or the number or/and size of the steps for changing an ultrasound parameter. For example, the graphical user interface has two entry fields in which a starting parameter and an end parameter for a sector scan can be predefined. This is done, for example, by means of two arrow keys, respectively, next to the entry field, via which the parameter in the corresponding field can be increased or reduced. In another entry field of that type, the number or/and size of the steps can be determined in an equivalent manner, for example. Corresponding entry fields can be provided for other ultrasound parameters. 
         [0041]    A method according to embodiments for the non-destructive ultrasound testing of workpieces comprises providing a device comprising an ultrasonic test probe with an ultrasonic transducer, an electronic control unit and an input unit disposed on the ultrasonic test probe. The device can be configured in accordance with one of the embodiments described above. Furthermore, the method comprises the step of actuating the input unit disposed on the ultrasonic test probe for issuing a control command, as well as the step of transmitting the control command to the electronic control unit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0042]    Exemplary embodiments of devices are described below, supported by the Figures and not to be understood as limiting. Of course, all of the features of the above-described embodiments and the following exemplary embodiments can be combined in any way, provided this is technically possible. Elements that are the same functionally are designated with the same reference numerals. The Figures show: 
           [0043]      FIG. 1 : a schematic representation of the ultrasonic test probe  10  of a device according to a first embodiment, 
           [0044]      FIG. 2 : a schematic representation of the ultrasonic test probe  10  of the device according to the first embodiment, 
           [0045]      FIG. 3 : a schematic representation of the ultrasonic test probe  10  of the device according to the first embodiment, 
           [0046]      FIG. 4 : an exemplary embodiment of an alternative ultrasonic test probe  10  for use in a device according to an embodiment, and 
           [0047]      FIG. 5 : a second exemplary embodiment of a device according to an embodiment with a graphical user interface. 
       
    
    
     DETAILED DESCRIPTION 
       [0048]      FIGS. 1 to 3  show schematic representations of an ultrasonic test probe  10  for use in a device, wherein the mode of operation of the input unit  12  according to a first embodiment, which is disposed on the ultrasonic test probe  10 , is described. 
         [0049]    The ultrasonic test probe  10  is disposed on the surface of a workpiece  26 . It comprises a housing  16  and an input unit  12  disposed thereon and, not shown here, an ultrasonic transducer with several individually controllable segments for transmitting/receiving ultrasonic signals  24 , which here are outlined as directional arrows. In the exemplary embodiment shown, the input unit  12  comprises a joystick with an operating lever  14  which has a defined rest position  23  and is pivotable in two planes that are perpendicular to each other, i.e. the x-z plane and the y-z plane, as is shown in  FIGS. 1 and 2 . The input unit  12  is configured for communication with an electronic control unit  30  comprising a transmitting/receiving unit  40  for communication with the ultrasonic transducer. The change of an input parameter of the joystick is converted via the transmitting/receiving unit  40  of the electronic control unit  30  into a change of an ultrasound parameter. 
         [0050]    A deflection of the operating lever  14  relative to its rest position  23  in the x-z plane is detected as a change of a deflection angle  21  relative to the rest position  23  and processed by the input unit  12  as a control command by the user. The control command is transmitted to the transmitting/receiving unit  40  of the electronic control unit  30  and used for the control of the ultrasonic transducer. For example, a change of the deflection angle  21  leads to a change of the insonification angle  20  of the ultrasonic field in the workpiece. 
         [0051]    In the exemplary embodiment shown, a change of the deflection angle  21  in the x-z plane is converted into a corresponding change of the insonification angle  20 , which the emitted ultrasonic signals  24  form in the workpiece with the normal  22  on the workpiece surface  26 , as shown in  FIG. 1 . 
         [0052]    In contrast, the change of the deflection angle  21  of the operating lever  14  in the y-z plane causes a change of the transverse angle  19 , with the insonification angle  20  remaining constant. 
         [0053]    For example, an absolute change of the deflection angle  21  in the x-z plane of 25° is converted with a conversion factor of  1  into a pivoting of the insonification angle  20  by 25°. 
         [0054]    In an embodiment, the conversion factor between the change of the deflection angle  21  of the operating lever  14  of the joystick and the change of the insonification angle  20  of the ultrasonic signals  24  in the workpiece can be varied, for example by means of the keys of the input unit  12  or the buttons on the GUI  50 . 
         [0055]    Moreover, the joystick is configured so as to be rotatable about its operating lever  14 . A rotary movement of the operating lever  14  will be converted into a change of the focusing depth of the ultrasonic field in the workpiece. For example, the angle of rotation of the operating lever  14  of the joystick is detected and, depending on the direction of rotation, converted into an increase or reduction of the focusing depth, as is indicated by the partially dashed directional arrows of different lengths in  FIG. 3 . For example, the conversion factor between the angle of rotation and the change of the focusing depth can be varied, for example by means of the keys of the input unit  12  or the buttons on the GUI  50 . 
         [0056]      FIG. 4  shows another exemplary embodiment of an ultrasonic test probe  10  of a device. Its input unit  12  comprises a plus key  17  and a minus key  18 . The change of a conversion factor between the input parameter and the controlled ultrasound parameter is done by the user by actuating the plus key  17  or the minus key  18 . An actuation of the plus key results in an increase of a conversion factor by a certain factor or a certain value, and an actuation of the minus key  18  leads to a corresponding reduction of the conversion factor. 
         [0057]    All relevant conversion factors for the ultrasound parameters can be increased/reduced via the plus key  17  and the minus key  18 . Which conversion factor is currently being changed is determined separately. For this purpose, the input unit  12  comprises a rotary disk  11  suitable for assuming various discrete positions  9 . For example, the positions  9  are labeled with markings on the rotary disk  11  and the housing  16  of the ultrasonic test probe  10 . The position  9  of the rotary disk  11  determines the ultrasound parameter whose conversion factor is varied via the plus/minus keys  17 / 18 . 
         [0058]    Moreover, the joystick comprises a key  13  disposed on the operating lever  14 . An actuation of the key  13  by the user results in the freeze of the ultrasound parameters. It is preset, for example, that a change of the insonification angle  20  is carried out starting from an initial value of 0° in accordance with the change of the deflection angle  21  of the joystick. A deflection of the operating lever  14  in the x-z plane by 20° now causes a change of the insonification angle  20  from the initial value of 0° to the end value of 20°. By actuating the key  13 , the end value of 20° is stored as the new initial value, and a new change of the deflection angle  21  in the x-z plane by 20° now causes a change of the insonification angle  20  from 20° to 40°. 
         [0059]    Moreover, the joystick comprises another key  13 ′ disposed on the operating lever  14 . The key  13 ′ is configured to trigger a snapshot of the received ultrasonic signals  24  upon actuation by a user. 
         [0060]      FIG. 5  shows a schematic representation of another exemplary embodiment of a device for non-destructive ultrasound testing. The device comprises an ultrasonic test probe  10 , which is configured for communication with an electronic control unit  30 . 
         [0061]    The ultrasonic test probe  10  is disposed on the surface of a workpiece  26 , comprises a housing  16  and an input unit  12  disposed thereon and, not shown here, an ultrasonic transducer with several individually controllable segments for transmitting/receiving ultrasonic signals  24 , which here are outlined as directional arrows. 
         [0062]    By means of a WiFi connection  35 , the input unit  12  is configured for communication with the electronic control unit  30 . The electronic control unit  30  comprises a transmitting/receiving unit  40  configured for communication with the ultrasonic transducer for the purpose of transmitting or/and receiving ultrasonic signals  24 , an evaluation unit  60  for processing received ultrasonic signals  24 , and a graphical user interface  50  with a cursor  51 . 
         [0063]    Via the graphical user interface  50  of the electronic control unit  30 , the ultrasound parameters of the emitted ultrasonic signals  24  can be varied by means of the transmitting/receiving unit  40 . The ultrasonic signals  24  received by means of the transmitting/receiving unit  40  are displayed on the graphical user interface  50  by an imaging unit  70 , for example as an A-scan, a B-scan or as a sector scan. The evaluation unit  60  of the electronic control unit  30 , which is configured for communication with the transmitting/receiving unit  40 , enables the processing of received ultrasonic signals  24 , for example filtering them, amplifying them or storing them. 
         [0064]    The processing of received ultrasonic signals  24  and the change of the ultrasound parameters of ultrasonic signals  24  emitted into the workpiece is effected by means of different buttons within the graphical user interface  50  that can be activated by the cursor  51 . 
         [0065]    The input unit  12  shown in  FIG. 5  substantially corresponds to the input unit  12  known from  FIG. 4 . Reference is made to the explanations there. In addition, the input unit  12  shown in  FIG. 5  comprises a switch  55 ′, with which it is possible to switch between the two operation modes. 
         [0066]    A movement of the operating lever  14  of the joystick in the x-z plane in the second operation mode is not converted into the change of the insonification angle  20 , but into a corresponding movement of the cursor  51  within the graphical user interface  50 . If the cursor  51  is located within the graphical user interface  50  on a button, the latter is activated by actuating the key  13 . 
         [0067]      FIG. 5  shows several buttons within the graphical user interface  50  in the form of pull-down menus  52 , entry fields  54 ,  54 ′,  54 ″ and a virtual switch  55 . For example, a starting parameter and an end parameter for changing an ultrasound parameter can be entered into the entry fields  54  and  54 ′, and the number of steps in which the variation of the ultrasound parameter is to take place is entered into the entry field  54 ″. For example, the insonification angle of the ultrasonic signals  24  is to be changed from 0° to 20°. The entry fields  54 ,  54 ′,  54 ″ have two arrow keys  56 ,  56 ′,  56 ″ that respectively increase or reduce a numerical value in the corresponding entry field  54 ,  54 ′,  54 ″ by a certain value. A value of 0 is entered into the entry field  54 , and the value  20  is entered into the entry field  54 ′. The value  20  is also entered into the entry field  54 ″. The start of a testing sequence, for example by means of a corresponding button within one of the pull-down menus  52 , then causes a periodic pivoting of the angle of the insonification angle  20  from 0° to 20° in  20  steps of 1° each. 
         [0068]    Via the pull-down menus  52 , for example, it is possible to select for which ultrasound parameter the starting parameter and the end parameter as well as the number of steps for changing the corresponding ultrasound parameter takes place via the entry field  54 ,  54 ′ and  54 ″. 
         [0069]    Other functions for processing the received ultrasonic signals  24  of for beam control are also located within the pull-down menu  52 . 
         [0070]    According to a particular exemplary embodiment, it is possible to switch at any time between the use of the joystick for manipulating the ultrasound parameter and the navigation by means of the graphical user interface  50 , for example by means of a switch  55 ′ on the input unit  12  and a corresponding virtual switch  55  within the graphical user interface  50 . 
         [0071]    In this exemplary embodiment, it is possible to follow on the graphical user interface  50  how the received ultrasonic signals  24  change when the ultrasound parameters are changed. For example, the change of the received ultrasonic signals  24  can be followed by means of the imaging unit  70 . 
         [0072]    For example, the change of an ultrasound parameter from a starting parameter towards an end parameter is displayed at the same time in the entry buttons  54  and  54 ′. Another entry button  54 ″ is also provided in which the current conversion factor between the change of an input parameter and an ultrasound parameter is displayed. 
         [0073]    With such a device, an intuitive presetting of the ultrasound parameters can be carried out by actuating a mechanical operating element of the input unit  12 . It is possible to track what the settings are that are currently being used. A fine tuning of the parameters can be carried out via the buttons within the graphical user interface  50 . For example, it may be beneficial to approximate an optimum focusing depth for the analysis of a flaw in the workpiece by rotating the operating lever  14  and to then set it precisely via the arrow keys  56 ′ of an entry field  54 ′. 
         [0074]    It is to be understood that even though numerous characteristics and advantages of various embodiments have been set forth in the foregoing description, together with details of the structure and functions of various embodiments, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. It will be appreciated by those skilled in the art that the teachings disclosed herein can be applied to other systems without departing from the scope and spirit of the application.