Abstract:
A touch screen is disclosed which responds to a user&#39;s touch for re-drawing, re-scaling, re-translating and re-positioning an impedance plane signal received from non-destructive testing equipment, such as an eddy current sensor. The impedance plane is manipulated by slidingne, two or more fingers simultaneously to an end position to effectuate a complete re-drawing operation of the image.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to non-destructive testing and inspection systems (NDT/NDI), using more specifically Eddy Current Technology (ECT), Eddy Current Array technology (ECA), Pitch-Catch Bond Testing (PCBT) and Resonance Bond-Testing (RBT). 
       BACKGROUND OF THE INVENTION 
       [0002]    Eddy current inspection is commonly used as non-destructive control to detect flaws in surfaces of manufactured components fabricated from a conductive material, such as bars, tubes, and special parts for the automotive, aeronautic or energy industries. 
         [0003]    Since the 1950&#39;s, eddy current instruments render test information on an impedance plane display. The original concept of the impedance plane display was to divide the detector coil impedance into resistive and reactive components to produce bi-dimensional figures yielding significant information on the inspected component. The concept quickly evolved as users understood the value of manipulating the impedance plane to highlight specific features of the component to be tested. 
         [0004]    Portable eddy current instruments now offer many controls to achieve these impedance plane manipulations, including: gain, rotation, horizontal position, vertical position, horizontal gain and vertical gain. All controls are typically accessible in various instrument menus and are iteratively applied by the instrument user to produce the desired impedance plane setup. This operation can become time consuming as the user needs to go through the whole sequence before each new inspection procedure (sometimes twice for a dual frequency setup). Thus, there is a need for an easier and faster way to manipulate the impedance plane on NDT equipment, such as a portable eddy current instrument. 
         [0005]    Another limitation of the current method is the troublesome interaction between some parameters such as vertical gain and rotation, which require some additional care when instruments settings are defined. 
         [0006]    More specifically, some additional drawbacks involved in a typical prior art portable eddy current instrument featuring an eddy current impedance plane that shows signal produced by scanning a defect with a probe and the controls available for manipulating this impedance plane signal to enhance the detectability of defect signal over noise signal, are as follows. These controls typically involve the use of multiple buttons associated with multiple parameters displayed on the instrument screen. Parameters found on most eddy current instruments include impedance plane rotation angle, gain, horizontal gain, vertical gain and settings to configure the horizontal and vertical position of the null point. The parameters for impedance plane manipulation are sometimes located in various sub-menus of the instrument. The values for each parameter are typically modified with a knob or by using a keypad. 
         [0007]    An inspection procedure typically describes the desirable signal shapes on a reference block in order to obtain a reliable and repeatable inspection. Those procedures typically require setting the noise signal on the horizontal axis and defines the other parameters to maximize the detectability of defect signal on the vertical axis in order to decouple the defect and noise signals. Furthermore, since eddy current parameters are closely related to probe selection, inspection condition and target defects, those parameters must be set before any inspection task. 
         [0008]    The original impedance plane signal is iteratively modified to highlight the defect signal with the prior art method. Consecutive steps typically include gain adjustment, signal rotation, vertical gain adjustment, vertical movement of the null point and horizontal movement 14 of the null point. Those operations are often conducted on live data (in this case the user needs to repeatedly scan the defect area) or on paused (frozen) data. In the latter case, some post processing is used to manipulate the data previously acquired to reflect in real time changes made on the original signal. For purposes of illustration, the figures and descriptions provided herein are more oriented toward frozen data style manipulation. 
         [0009]    Multi-point touch screen displays now available on the market make it possible for users to directly interface with instruments without going through menus and sub-menus. This invention provide means to benefit from a multi-point touch screen to provide new ways to manipulate an impedance plane and to circumvent current limitations of prior art methods. 
         [0010]    An object of the invention is to reduce the number of steps required for the controls so as to produce an equivalent end result and thus to increase productivity. 
         [0011]    Another object is to provide a simplified and more intuitive operation which, in turn, provides an enhanced user experience. 
       SUMMARY OF THE INVENTION 
       [0012]    The invention is a multi-point touch screen apparatus, system, means and a method of using the same in order to manipulate an eddy current impedance plane signal. The invention make it possible conduct substantially all required impedance plane manipulations in fewer steps while providing a more intuitive interaction as the user can be empowered with the feeling that he or she is actually controlling or adjusting the signals directly with his or her hand. 
         [0013]    Other features and advantages of the present invention will become apparent from the following description of the invention, which refers to the accompanying Drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a schematic depiction of an eddy current instrument built in accordance with the teaching of the invention. 
           [0015]      FIG. 2  illustrates various possibilities regarding parameter selection through the use of a touch screen interface according to an aspect of the invention. 
           [0016]      FIG. 3  illustrates a basic process behind the impedance plane signal&#39;s manipulations using the touch screen interface according to an aspect of the invention. 
           [0017]      FIG. 4  illustrates a manipulation of the impedance plane when horizontal and vertical gains are different according to an aspect of the invention. 
           [0018]      FIG. 5  illustrates how the impedance plane is manipulated when some parameters are fixed according to an aspect of the invention. 
           [0019]      FIG. 6  illustrates various single contact operations possible according to an aspect of the invention. 
           [0020]      FIG. 7  illustrates how a five step sequence of prior art methods may be performed with two steps according to an aspect of the invention. 
           [0021]      FIG. 8  is a flow diagram illustrating the operation illustrated in  FIG. 3  according to an aspect of the invention. 
           [0022]      FIG. 9  is a flow diagram illustrating the operation illustrated in  FIG. 4  according to an aspect of the invention. 
           [0023]      FIG. 10  is a flow diagram illustrating the operation illustrated in  FIG. 5  according to an aspect of the invention. 
           [0024]      FIG. 11  is a flow diagram illustrating the operation previously illustrated on  FIG. 6  according to an aspect of the invention. 
           [0025]      FIG. 12  is a flow diagram describing the operation previously illustrated on  FIG. 6   b  according to an aspect of the invention. 
           [0026]      FIG. 13  is a flow diagram describing the operation previously illustrated on  FIG. 6   c  according to an aspect of the invention. 
           [0027]      FIG. 14  is a block diagram showing components of a Non-Destructive Instrument Data Touch Screen Engine, according to an aspect of the invention. 
       
    
    
       [0028]    With reference to the Drawings, the features thereof are described below. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0029]      FIG. 1  is a first overview of an instrument  200  built in accordance with an aspect of teachings of this invention using a multi-point touch screen interface  240  and displaying the impedance plane  1  for representing the impedance plane signal  8  and displaying a set of buttons  201 ,  202 ,  203 ,  204 ,  205 ,  206 ,  207  and  208 . 
         [0030]    A benefit of the use of a touch screen is the integration of the buttons and displayed parameters to provide the user with a set of buttons  201 ,  202 ,  203 ,  204 ,  205 ,  206 ,  207  and  208 . According to an aspect of the invention, a touch screen interface provides the user with the ability to manipulate impedance plane signal  8  without using knob  220  (although  220  can still be used for some precise operations). They may also have ability to modify simultaneously many parameters of the impedance plane with a single touch screen operation. 
         [0031]      FIG. 2   a  shows how parameters to be modified are first selected on the touch screen interface. Buttons  204  (rotation angle),  205  (horizontal gain),  206  (vertical gain),  207  (horizontal position) and  208  (vertical position) refer to individual parameters. Selecting one such parameter on the touch screen, as seen in  FIG. 2   a , makes it possible to modify these values on touch screen interface  240  or with knob  220 . Now looking at  FIG. 2   b , selecting button  202  (gain) simultaneously activates buttons  205  and  206  and makes it possible to modify both values on touch screen  240  or with knob  220 . Similar results can be achieved with button  203  (null point position) which activates  207  and  208  except that combined position  207  and  208  can only be modified using the touch screen interface  240 . Preferably, as shown in  FIG. 2   c  button  201  may be provided to allow a user to select all parameters simultaneously in order to benefit fully from the touch screen operation. For the touch screen operation, it is also possible to combine any selection of parameters as shown in  FIG. 2   d , where  202  and  204  have been selected. 
         [0032]    Reference is now made to  FIG. 14  presenting the forgoing description with an overall context within a Non-Destructive Data Touch Screen system  1501 . The NDT signal data, such as from an eddy current probe, are gathered in an impedance plane data database  1511 . Based on this data, impedance plane data processing module  1515  provides information to touch screen graphic rendering module  1523  sufficient to draw an image representing the impedance plane signal on touch screen  240 . 
         [0033]    Touch screen sensing  1521  signals to touch screen user selection module  1525  that the user has touched using one or more fingers, or using other parts of his hand, the touch screen interface  240 . That is, touch screen user selection module  1525  detects what user&#39;s selection of the parameter and gives a context for the subsequent touch screen input, then transmits such touch input to impedance plane data processing module  1515  the coordinates, direction, pattern and/or timing of the touch of the user. Based on this information, impedance plane data processing module  1515  transmits instructions to touch screen graphic rendering module  1523  to redraw the image of the impedance plane signal on touch screen interface  240  based on the user&#39;s touch. 
         [0034]    In order to understand principles underlying an aspect of the invention, first consider the case where all parameters are selected (step  1102  in  FIG. 8 ) and where horizontal and vertical gains  205  and  206  have the same value. In this case, as shown on  FIG. 3  and FIG.  8  the impedance plane  330  and corresponding impedance plane signal  350  is modified by pressing and holding two point contacts  301  and  302  to their final position  301 ′ and  302 ′ (step  1106 ). 
         [0035]    The whole impedance plane is morphed (scaled, translated and rotated) (step  1108 ) in order to keep the triangle  320  (defined by  301 ,  302  and  340 ) shape constant with the position of contact points  301 ′ and  302 ′. As part of the process, the new position of null point  340 ′ is defined and the information previously located under  301  and  302  is now under  301 ′ and  302 ′. A preview of the modified impedance plane  331  is constantly displayed to the user (step  1109 ). Once the user obtains the desired signal  350 ′and removes his fingers from the touch screen, the modified instrument parameters  204 ,  205 ,  206 ,  207  and  208  are applied (step  1112 ) to the instrument and impedance plane  331  is displayed (step  1114 ). 
         [0036]    Now a more complex situation is considered as illustrated in  FIG. 4  and  FIG. 9 , where the vertical gain and horizontal gain are different. In this case, the vertical gain is superior by 6 dB, but the explanation and concepts described here are applicable for any gain configuration. At the beginning of the process, the original impedance plane signal  450  is selected at positions  401  and  402  and moved to  401 ′ and  402 ′ (step  1206 ). To evaluate the impact of touch screen operation  411  on signal  450 , a first step  1208  is made to remove the gain difference on the various features of  430  to get impedance plane  330 , signal  350  and contact position  301  and  302 . 
         [0037]    Then, the new contact positions  401 ′ and  402 ′ are processed through step  1209  to remove the gain difference in order to obtain new contact positions  301 ′ and  302 ′ on impedance plane  331 . 
         [0038]    Because the gain difference have been removed in previous steps  1208  and  1209 , Step  1210  which makes it possible to calculate signal  350 ′ and null position  340 ′ on the impedance plane  331  is the same way as step  1108  previously described in  FIG. 8 . We now complete the process by applying back the gain difference (in this case +6 dB on the vertical axis) in step  1212 . The resulting impedance plane  434  provides the user with morphed signal  450 ′ and updated null position  440 ′ (step  1213 ). Note that in this case a portion  460  of  450 ′ is out of  434  and is thus removed from the information displayed to the user. Once the user obtains the desired signal and removes his fingers from the touch screen, the modified instrument parameters  204 ,  205 ,  206 ,  207  and  208  are applied (step  1216 ) to the instrument and the whole impedance plane  434  is displayed (step  1218 ). Steps  1208 ,  1209  and  1210  can be performed automatically by the system. 
         [0039]    When only a few parameters are selected, such as illustrated in  FIG. 2   a ,  FIG. 2   b  and  FIG. 2   d , calculations are essentially similar to those described in  FIG. 8  and  FIG. 9  except that only selected parameters are modified by the process. The example shown in  FIG. 5  and  FIG. 10  illustrates the behaviors of the system when touch screen operation  311  is made on impedance plane  330  with parameter selection illustrated on  FIG. 2   d  to provide an impedance plane  501 . In this case the translation parameters  207  and  208  are discarded step  1308 . 
         [0040]    In addition to the previously described two contact operation, it is possible to manipulate the impedance plane with a single contact in some situations. For example, as illustrated on  FIG. 6   a  and  FIG. 11 , if the angle  204  is the only selected parameter (step  1402 ) when contact  601  is moved toward its final position  601 ′ (step  1406 ), the impedance plane will be rotated by an angle  660  defined by the  601  and  601 ′ versus null point  340  (step  1408 ).  FIG. 6   b  and  FIG. 12  illustrate the situation in which gain  202  is selected (step  1422 ). In this case signal  350  is scaled by the ratio defined by  661  and  662  (step  1428 ), while the null position  340  remains unchanged. It is of course possible to affect only vertical gain  206  or horizontal gain  205  with the same method. Another possibility shown in  FIG. 6   c  and  FIG. 13  shows the effects of single contact movement when position  203  is selected (step  1442 ). In this case, null point  340  and signal  350  are translated vertically  663  and horizontally  664  to provide the new positions of the signal  653  and null  640  (step  1448 ) on the impedance plane  632 . It is of course possible to affect only the vertical position  208  or horizontal position  207  with the same method. 
         [0041]    Some parameters, such as position and gain, can also have a limited range of variability. Typically, the null position will be kept within the impedance plane display; the gain can also be limited to reflect some limitation of the test equipment. In this case, the operation described in  FIGS. 8-11  can be limited according to these predefined parameter&#39;s range. 
         [0042]    Now looking at  FIG. 7 , we see how results equivalent to a prior art process can be achieved with only two operations  20  and  21  using the touch screen based method of the invention while the prior art process requires at least the five following steps: gain modification, signal rotation, vertical gain modification, vertical position translation and horizontal position translation. The first operation  20  combines signal rotation, Gain and null position translation (horizontal and vertical) using a two point contact on the touch screen interface  240 . The second operation  21  involves a modification limited to the vertical gain using only a single point contact on the touch screen interface  240 . 
         [0043]    The teaching of the invention also applies for eddy current test instruments capable of handling more than one test signal (for example with dual frequency testing or multi-channel instruments). In this case, the instrument should provide the ability to select one impedance plane signal at a time in order to conduct the manipulations. 
         [0044]    The method to render the impedance plane preview (steps  1109 ,  1213 ,  1309 ,  1409 ,  1429  and  1449 ) is dependant on the processing capabilities of the test instrument. An instrument with sufficient processing capabilities will render the full impedance plane manipulation in real time to provide the user with a full feedback of the signal resulting from the process. A more limited instrument could provide feedback on a few important signals such as peaks, NULL position, etc. Indications showing the locations of the contact on the touch screen could also be useful to conduct the manipulation. 
         [0045]    Impedance plane manipulations with the touch screen approach described herein are possible when the acquisition is stopped (frozen data manipulation, as first discussed in paragraph 8) or when the acquisition is running. In the later case, it is proposed to freeze the display during the manipulation itself from the touch of the screen to the release of the contact (with a possible delay). 
         [0046]    Although discussed with respect to a touch screen device, it would be understood that other types of displays that provide for user manipulation of an image using a mouse, a separate control pad, a trackball or track pad, a joystick, arrow directional controls, or other types of controls separate from or in addition to the touch screen, are also contemplated and could be readily substituted by a person of ordinary skill in the art within the spirit of the present invention. In addition, as would be readily understood, a user need not touch some types of touch screens to effect (touch) or input to the touch screen. That is, the user may hover over or merely point to portions of a touch screen and sensors will detect the user&#39;s hand or finger, including the direction, timing or other pattern thereof, and this movement of the user&#39;s hand or finger away from the touch screen would be accurately interpreted as interacting with or directing or controlling the displayed image on the screen. 
         [0047]    Touch screens may use various types of display systems, including LEDs, LCDs, CRTs, OLED, displays or other types of electronic displays to convey electronic information or electronic image information to the user. The buttons  204 - 208  illustrated in  FIG. 1  and  FIGS. 2   a - 2   d , may be implemented as soft buttons or may be provided as separate physical buttons adjacent to the touch screen  240 . Although shown as a wired connection between probe  130  and instrument  200 , it will be understood that other types of connection, including a wireless connection implemented via Bluetooth or other types of close or medium distance radial frequency or other frequency technology, including, for example, cellular or other types of wireless signaling, are also contemplated. 
         [0048]    It must also be understood that impedance plane manipulation using the touch screen can apply on previously acquired impedance plane data  1511  and/or on live data (i.e. data to be acquired be the system). For live data, impedance plane manipulations can be limited to digital modifications or can effectively modify some analog setting (for example analog GAIN) in the instrument. 
         [0049]    Other possible applications of the invention are bond testing instruments which also rely on the impedance plane for defect detection. 
         [0050]    Although the present invention has been described in relation to particular embodiments thereof, many other variations, combinations of features 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.