Abstract:
Disclosed is an inspection device and method of guiding an inspection probe according to a predetermined inspection plan. The device is couple with a probe which is to be moved according to the inspection plan on the test object, the device including an inspection guide unit having a guide control unit, a position encoding such as a 3-D camera and visual feedback eyewear. The method including facilitating a virtual display of the inspection plan onto the visual feedback eyewear, moving the probe following the virtual display of the inspection plan, sensing sensed probe positions in real time of the inspection using the 3-D camera and validating the sensed probe position against the inspection plan using the control module. Then the information of the step of validating, such as those spots at which the probe is moved out of the tolerance of the inspection plan, is displayed on the feedback eyewear.

Description:
FIELD OF THE INVENTION 
       [0001]    The present disclosure generally relates to a method and a system for conducting non-destructive testing/inspection (later as NDT/NDI), and more particular, it relates to guiding and informing an inspector in real time of an inspection path during a manual inspection of a test object. 
       BACKGROUND OF THE INVENTION 
       [0002]    Inspection of complex parts by non-destructive technologies can be quite challenging as finding and sizing a flaw or defect heavily depends on probe positioning during inspection. In the exemplary embodiment of this invention, a nozzle weld phased array ultrasonic (PAUT) inspection is used. The exact position and number of required PAUT scan lines on particular nozzle geometry is defined by the scan plan, knowing that for weld inspection the whole weld zone must typically be completely covered by the various PAUT beams. The complex shape of the nozzle, defined by the intersection of two cylinders, makes it difficult to follow the inspection scan line to ensure correct coverage of the inspected weld as defined by the scan plan. 
         [0003]    The conventional way of conducting PAUT nozzle inspection is manually, with or without a guide on the part. The user must be experienced as he needs to compensate for the effects of the geometry on the ultrasound signal path in order to achieve the interpretation of the scan result. Because such an inspection relies heavily on the user&#39;s experience, reproducibility and reliability is poor. Under those conditions, it is also impossible to ensure the complete part was covered and to save meaningful data as the real position of the probe is unknown to the inspection system. 
         [0004]    A more robust way of inspecting a nozzle is to use an automated scanner, specific to the nozzle geometry, which encodes all PAUT probe movement and ensures coverage by precisely positioning the probe on the inspected part surface. Such a scanner is an expensive alternative and is not suitable for all markets. It also takes a lot of time to deploy, install and it lacks the manual versatility to better size a flaw or defect. 
         [0005]    Either solution requires having a scan plan which is calculated depending on measured parameters of the nozzle such as radius, thickness, pipe thickness and pipe radius. 
         [0006]    Advances in technologies now permit a probe to locate an object with very good precision without the use of a specific scanner. In the preferred embodiment, the chosen encoding unit is a 3D camera that uses two specific objectives to locate a moving target, which reflects infrared, using the stereoscopy principle. Attempts have been made to use such advanced encoder systems for the manual inspection of complex geometries such as the nozzle. While these attempts solved some of the limitations of manual inspection (such as traceability and analysis) it has not been devised as an effective tool for guiding the probe position during the inspection. 
         [0007]    It would be desirable to have a way of using the advanced encoding unit, a 3D camera, to provide adequate feedback of the scanning path during the inspection in order to significantly increase the accuracy and efficiency manual inspection. 
       SUMMARY OF THE INVENTION 
       [0008]    Disclosed is a visual scanning guide system and method for guiding a scan path of a manual NDT/NDI process as it inspects flaws along a predetermined inspection line. In the exemplary embodiment, the guide system assists the inspection of a nozzle to pipe weld using a PA Ultrasound technique. Preferably by using an existing automated wizard with known geometric parameters of the pipe and nozzle, configuration information regarding a desirable path to scan the weld in order to have full coverage is provided. The configuration information also includes operational parameters such as the beam formation to use, which part of the signal is meaningful (gating), what scan line to follow and the number of passes that are necessary to have a full coverage. An acquisition unit of the PA system is configured according to the parameters above and is ready to inspect. 
         [0009]    The visual scan guide system embodies a position encoding unit which is preferably a 3D camera to report real time position and orientation of the probe. Also embodied is a pair of Referenced Feedback glasses, which is partially see-through and partially a screen that can display images generated by a scan path control module. The glasses is configured to display part of the configuration information, such as the desired scanning path, and to allow wearers or inspectors to see through to observe where the probe&#39;s location is in relationship to the desired scanning path. As the inspection continues, the user is informed on the screen of the glasses with information from the scan path control module, including a bad position of the probe, the lack of coupling fluid and the found flaw or defect position. If the probe capability permits it, the system compensates for small positioning errors by modifying the beam formation to alleviate the error. Since only meaningful data is saved, the analysis of the resulting data is simplified and a proper coverage of the weld can be proven. 
         [0010]    The novel aspects of the present invention can be summarized as to include, 
         [0000]    The integration of an automatically calculated scan plan, a position encoding unit and a visual feedback unit (the glasses) to provide real time information guiding the user to follow the planned scan path;
 
The usage of an encoding unit (a 3D camera is exemplarily used) to dynamically correct the focal laws in order to maintain a detection capability as defined in a scan plan.
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a schematic diagram showing the presently disclosed phased array system with the visual guide to assist a manual NDT inspection. 
           [0012]      FIG. 2  is a schematic view showing a scan plan representation on theoretical part, including tolerances and a sample inspection with positioning error/variation from the scan plan. 
           [0013]      FIG. 3  is a schematic view of the visual guide unit showing the assembly of the 3D camera used as the position encoding unit and the visual feedback glasses. 
           [0014]      FIG. 4  is a schematic view showing the automatic beam steering adjustment assisted by the visual guide unit. 
           [0015]      FIG. 5  is a flow chart detailing the steps in providing the visual guide to the PA scanning process. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Referring to  FIG. 1 , the presently disclosed PA system  10  with visual guide  22  comprises a phased array probe  210 , a data acquisition unit  14 , an inspection preparation module  12 , a position encoding unit  16 , a scan path control module  18  and a visual feedback unit  20 . Probe  210  and data acquisition unit  14  are all existing elements of a conventional phased array system and communicate information, such as inspection signals and operational commands, among each other. Added to the conventional PA system is a visual guide unit  22  (Details are shown in  FIGS. 2 and 3 ) which is an assembly of a scan path control module  18 , position encoding unit  16  and visual feedback unit  20 . 
         [0017]    Still referring to  FIG. 1 , scan path control module  18  is configured to perform the following functions:
       receiving inspection plan from inspection preparation module  12 ,   updating data acquisition unit  14  with the correct configuration,   retrieving position and orientation of the part and probe from position encoding unit  16 ;   validating probe position and beam orientation with respect to tolerances,   calculating beam steering modification to program the data acquisition unit  14  in order to meet beam orientation tolerances,   preparing information to be displayed by the visual feedback unit  20 .       
 
         [0024]    The inspection is first prepared by inspection preparation module  12  with a few simple geometric definitions of the test object such as diameters and thicknesses of the pipe and nozzle, and their geometric relation to one another. Using the information, an existing automated wizard is used to provide configuration information regarding a desirable path to scan the weld in order to have full coverage. The configuration information also includes operational parameters such as the beam formation to use, which part of the signal is meaningful (gating), what scan line to follow and the number of passes that are necessary to have a full coverage. Acquisition unit  14  of the PA system is configured according to the parameters above and is then ready to inspect. 
         [0025]    The position encoding unit  16  used in the preferred embodiment is a stereoscopic 3D camera, which can locate the position and orientation of its targets in space. Targets are in a standard 3D camera system, some of whose reflective patterns can be recognized by the camera unit to enable tracking them. To calibrate 3D camera  16 , for example, the test object position is tracked using a fixed target placed at a known position on the object, then the probe&#39;s target position and orientation is tracked in relation to the target fixed on the part. This allows visual feedback unit  20  to show the position and orientation of the probe on the real part and to locate it in a theoretical (virtual) part in order to make calculations and apply different tolerance conditions (shown in  FIG. 2 ). 
         [0026]    Continuing with  FIG. 1  and assisted by referring to  FIG. 2 , visual guide unit  22  also embodies a pair of visual feedback unit  20 , preferably employed in the form similar to that of “augmented reality glasses”. Augmented reality glasses exist in the market and are partially see-through and partially a screen that can display computer generated images related to what is really seen through the glasses. 
         [0027]    One of the novel aspects of the present disclosure is to configure a visual feedback unit in such a way to display part of the configuration information, such as the desired scanning path generated from the inspection preparation module  12 , to allow wearers or inspectors to see through to observe where the probe&#39;s location is, and to employ an encoding unit (3D camera  16 ) to correlate the probe location in relationship to the desired scanning path. 
         [0028]    Referring to  FIG. 2  for an exemplary use of the presently disclosed guide system for inspecting a weld line  213  joining a first pipe  225  with a second pipe  200 . Pipe  225  and pipe  200  together comprise a nozzle (later also referred as a test object or part)  224 . In order to use the presently disclosed guide system, a plurality of geometric parameters pertaining to inspection preparation module  12  is needed. These geometric parameters include nozzle radius, nozzle thickness, pipe radius, pipe thickness, etc. Based on these parameters module  12  calculates an inspection plan scan line  212 . It should be noted that this step of preparation of the scan line is also used by existing PA manual inspections, and it also can be optionally done by manual calculations, which is not the scope of the present invention. The present disclosure deals with the challenge of how to accurately and efficiently follow the scan line at a planned beam orientation  218  as shown in  FIG. 2 .  FIG. 2  also shows scan line tolerances  214  and  216  and planned beam orientation tolerances  220  and  222 . 
         [0029]    It should be noted that the calculation of the scan plan is used but is not one of the objectives of the present disclosure. The present disclosure deals with a novel guide unit ( 22 ) to make sure the probe is following the calculated scan plan. 
         [0030]    Continuing with  FIG. 2 , without the usage of the presently disclosed scan guide system, weld line  213  could be inspected with a wrong inspection line  310  which is outside of scan line tolerances  214  and  216  producing an invalid position area  312 . It also shows probe  210  could be operated at a wrong beam orientation angle  314  which is outside planned tolerances  220  and  222 . The glasses are firstly calibrated to the operational parameters above with the input as to where the nozzle is positioned relative to fixed target(s). Once the calibration is done the guide system can then provide guide to the user tracing the scan line to follow directly on the part through the Referenced Feedback glasses. 
         [0031]    Continuing with  FIGS. 2 and 3 , a sample inspection is shown. The user does its inspection along wrong inspection line  310 . Doing so, he moves probe  210  outside of scan line tolerances  214  and  216 . It creates invalid position area  312  that can be seen in visual feedback unit  20  by the fact that part of line  412  of the inspection plan scan line  212  has not been removed, thus that area is considered as not inspected and was not stored by scan path control module  18 . Later during the scan, a coupling problem happens and is seen in visual feedback unit (glasses)  20  as coupling error symbol  416 . Part of line  414  of inspection plan scan line  212  in that region is still visible. A bit further in the inspection, wrong beam orientation angle  314  goes outside planned beam orientation angle tolerances  220  and  222 . As before, part of line  418  has not been removed from inspection plan scan line  212 . As the inspection progress, the user can see remaining scan line  410  on part  224  to guide the rest of the inspection. When the user sees that parts of line  412 ,  414  or  418  have not been removed he can go back to finish a proper inspection of these sections. 
         [0032]    The two units  16  and  20  are preferably built into an integral assembly so that the physical position of visual feedback unit  20  in relation to position encoding unit  16  is known. There is a mechanical coupling (not shown) between two units  16  and  20  providing mechanical attachment between the two. This also serves the purpose of avoiding the need to track the units&#39; physical locations separately. 
         [0033]    Referring now collectively to  FIGS. 2 and 3 , as the inspection continues, the user is informed of the bad position of the probe, the lack of coupling fluid and the found flaw or defect position, which appears visually on the part of glasses  20  with the information fed by the control module  18 . If the probe capability permits it, the system compensates for small positioning errors by modifying the beam formation to alleviate the error.  FIG. 3  illustrates an example of visual guide provided during an inspection of weld line  213  guided by reference feedback glasses  20 . Visual guide unit  22  assembly has two functions. First function is to track probe  210  position and orientation using position encoding unit  16 . Second function is to display information, using visual feedback unit (glasses)  20 , such as a coupling error symbol  416 , a data value indication  420 , a remaining scan line  410  as well as sections of line  412 ,  414  or  418 , which need to be re-inspected as there was some problem during the inspection (See examples of problems given in  FIG. 5 ). 
         [0034]    Referring now to  FIG. 4 , which illustrates the dynamic beam orientation correction on a simple plane part  510  using probe  210 . Similar to the probe&#39;s location and trajectory detected by encoding unit  16  (3D camera), the probe&#39;s orientation angle is also sensed and provided to control module  18  by encoding unit  16 . Uncorrected beam orientation angle  514  is corrected by θ steering angle, which is calculated by scan path control module  18  and then communicated to data acquisition unit  14 , to get corrected beam orientation angle  516  which is perpendicular to weld  512 . 
         [0035]    Reference is now made to  FIG. 5 . In step  612  the inspection method begins with the creation of a predetermined inspection plan by inspection preparation module  12 . The plan is based on pipe  225  and pipe  200 &#39;s dimensions provided by the user which are: nozzle radius, nozzle thickness, pipe radius, pipe thickness. In step  614  inspection preparation module  12  provides information to scan path module  18  which sets up data acquisition unit  14  with calculated information including beam formation, gates for every beam, scan pattern(s), etc. 
         [0036]    In step  616  the user does the calibration of the position and orientation of inspection target (weld line  213 ) in relation to position encoding unit  16 . To have a good match of the measured position of probe  210  to weld line  213 , the user must place targets on  224  and on probe  210 , and then hold the position of probe  210  at a known position of part  224  at zero degree around pipe  200  with probe  210  facing the nozzle. That way the position of part  224  in the virtual space can be calculated and used as reference to display feedback information. 
         [0037]    Once calibrated, the position of probe  210  relative to weld line  213  and the position of referenced feedback glasses  22  relative to weld line  213  are known to the system. This enables visual feedback unit  20  to display inspection plan scan line  212  onto part  224 . At this state, the user can now begin the inspection, following inspection plan scan line  212  which will disappear step by step as the acquisition of valid inspection data is in progress (Also see  FIG. 3 ). 
         [0038]    In step  617  scan path control module  18  updates visual feedback unit  20  with inspection plan scan line  212  drawing to be followed by the user. 
         [0039]    In step  618  position encoding unit  16  and data acquisition unit  14  provide position and data values to scan path control module  18 . The data values and positions are matched together and then evaluated in the following steps. 
         [0040]    In step  620  position requirements validation is done by scan path control module  18 . There are two tolerances to be respected. First, scan line tolerances  214  and  216  restrict probe  210  position relative to inspection plan scan line  212 . Next, planned beam orientation tolerances  220  and  222  restrict the rotation of probe  210  relative to planned beam orientation angle  218  at that position. If probe  210 &#39;s path does not match the tolerances, scan path control module  18  attempts to adjust the beam formation to match them (step  624 ). Depending on the deviation from the tolerance and equipment used to do the inspection, a correct beam formation may not be found leaving the area uninspected.  FIG. 4  illustrates the dynamic steering correction on simple plane part  510  using matrix phased array probe. Uncorrected beam orientation angle  514  is corrected by θ steering angle to get corrected beam orientation angle  516  which is then perpendicular to weld  512 . The process then returns to step  618  to get the next acquisition point. 
         [0041]    It should be noted that if beam orientation angle is not able to be adjusted by step  624 , the warning sign from step  620  should direct the operator to readjust how the probe is held to correct the probe&#39;s orientation. 
         [0042]    In step  626  a coupling check is done by control module  18  to verify probe  210 &#39;s correct ultrasonic coupling with part  224 . If a bad coupling is detected, visual feedback unit  20  displays coupling error symbol  416  on part  224  (step  628 ) and the process returns to step  618  to get the next acquisition point. 
         [0043]    In step  630  visual feedback unit  20  displays data value indication  420  (in  FIG. 3 ) which is suspected as a flaw or defect at its real position on part  224 . User interprets and further determines the severity of the issue from the measurement of the phased array system. In step  632  scan path control module  18  stores the data value and its position. In step  634  visual feedback unit  20  removes the section of inspection plan scan line  212  that was inspected and the process returns to step  618  to get the next acquisition point. 
         [0044]    It should be noted that data acquisition unit  14  of type that&#39;s normally used by ultrasound phased array system is herein used in this embodiment as an exemplary case of applying the presently disclosed method and apparatus. The framework and teaching shown in the present disclosure can be readily applied to different NDT technologies such as eddy current, bond testing, etc., and such application to other types of inspection technologies should all be covered by the scope of the present disclosure. Data acquisition unit  14  can also be the same and/or share the same unit with the phased array system. 
         [0045]    It should also be noted that scan path controller  18  can be also implemented in the form of a series of executable routines, executed by a digital processor, such as that of the same process as the existing phased array system that the controller is integrated to. On the other hand, controller  18  can be on a stand-alone processor as deemed fit for different designs. The framework and teaching shown in the present disclosure can be readily applied to all the variations of designs pertaining to the scan path controller. 
         [0046]    It should be noted that 3D camera system is exemplarily used in this embodiment as position encoding unit  16  applying the presently disclosed method and apparatus. The framework and teaching shown in the present disclosure can be readily applied to different encoding technologies such as standard rotary encoders, 3D arms, magnetic encoding system, etc. and such application to other types of encoding technologies should all be covered by the scope of the present disclosure. 
         [0047]    It should be noted that visual feedback unit  20  which takes the form of glasses are herein used in this embodiment as an exemplary case of applying the presently disclosed method and apparatus. The framework and teaching shown in the present disclosure can be readily applied to different visual guide technologies such as Laser Projection System, on screen, etc; and such application to other types of visual guide technologies should all be covered by the scope of the present disclosure. 
         [0048]    It should be noted that position encoding unit  16  and visual feedback unit  20  are herein used in this embodiment as an integrated unit, referenced feedback glasses  22 . The framework and teaching shown in the present disclosure can be readily applied to separate units, position encoding unit  16  which tracks visual feedback unit  20  that then displays the feedback information relative to its position. It should also be covered by the scope of the present disclosure. 
         [0049]    It should be noted that in this embodiment, in step  624 , uncorrected beam orientation angle  514  is corrected by θ steering angle to get electronically corrected beam orientation angle  516  which is then perpendicular to weld  512 . The teaching shown in the present disclosure can be readily applied to other beam forming change that allows retaining proper acoustic coverage of the inspected zone. It should also be covered by the scope of the present disclosure. 
         [0050]    Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.