Abstract:
The present invention relates to a method for graphically displaying an image section of an object under examination ( 1, 18 ) having objects ( 2, 17 ) situated therein, in particular for the display of an image section of a building wall. The invention provides that the image section with the objects ( 2, 17 ) situated in the object under examination ( 1, 18 ) is displayed already while data acquisition by the position detector ( 3, 19 ) is taking place.

Description:
BACKGROUND INFORMATION  
         [0001]    The present invention relates to a method for graphically displaying an image section through an object under examination having objects situated therein, in particular for the display of an image section through a building wall having obstacles situated therein, and a position finder that is designed accordingly.  
           [0002]    In detecting the location of objects in a building wall, various possibilities for displaying the result of the location detection are known.  
           [0003]    The simplest possibility provides only a light-emitting diode and/or a buzzer for indicating the result of the location detection, whereby a warning signal is sounded when the result measured by a position detector exceeds a threshold value. This method for indicating the result of the location detection only enables a statement to be made about possible obstacles in the current position of the position detector, however. Moreover, the operator receives no quantitative information about the maximum possible drilling depth. Instead, he only receives qualitative information as to whether or not an object is even located beneath the position detector.  
           [0004]    It is further known that pointing devices, bar displays and/or buzzers with variable pitch may be used to indicate the result of the location detection, whereby the depth of an object located in a building wall determines the deflection of the pointer or bar, or the pitch. The operator is therefore also provided with quantitative information about the depth of a located object. In this case as well, however, the display of the result of the location detection only enables a statement about the permissible drilling depth at the current position of the position detector.  
           [0005]    In addition, a graphic display of the result of the location detection on an LCD screen is known from the NJJ-85A position finder marketed by the Japanese company JRC Radio Corporation. In this case, the position finder sends a signal into the building wall and the signal is reflected by objects located therein. The depth of the located object can be calculated based on the delay time of the reflected signal after emission until it is received by the position finder. After a line section is measured out on the building wall, the amplitude of the reflected signal is depicted graphically as a function of the delay time and the position on the line section. The operator can then identify objects in the building wall based on maximum amplitudes that stand out from the rest, and he can calculate the depth of the objects based on the delay time. This method of displaying results requires a considerable amount of experience in identifying objects and subsequently calculating the depth of the objects, however.  
           [0006]    Finally, a method for graphically displaying the results of a location detection is known from the HILTI Ferroscan locating device. With this device, the area of interest on the building wall is scanned in eight consecutive linear line sections measuring 60 cm each, and the position result of the individual linear scans is stored. After the scan is performed in two dimensions, a quasi-transparent view of the interior of the wall is displayed on an LCD screen. The depth of each individual location must be queried separately. The operator does not receive any information about any objects at the current position of the position detector while he is performing the scanning function with the position detector, however. Instead, the operator must first generate the required position data in a complex procedure.  
         ADVANTAGES OF THE INVENTION  
         [0007]    The present invention therefore provides a method for graphically displaying a result of a location detection and a position finder that is designed accordingly, with which a current image section through the building wall is displayed during the scanning function itself.  
           [0008]    The invention is not limited to the location detection of fixed objects such as water pipes, concrete reinforcements or electrical leads in a building wall, however. Rather, the invention is also suited in general for detecting the location of any objects in an object under examination. The term “object” is therefore intended to be understood as a general term in the context of the invention. It also includes cavities and moisture pockets, for example.  
           [0009]    A depth scale is preferably included in the image section through the object under examination, so that the operator can identify the depth of a located object immediately without having to perform complex calculations.  
           [0010]    It is preferable for the unit of measure of the depth scale to be adjustable and for it to be included in the image section for the operator&#39;s information.  
           [0011]    In the preferred embodiment, the located objects are displayed in the form of standardized symbols or graphic patterns, which advantageously results in a clear, understandable display.  
           [0012]    In a variant of the invention it is further provided that the located objects are depicted graphically different in the image section depending on their depth. For example, the located objects can be displayed in the image section in different colors, shapes, shades and/or sizes, depending on their depth. The objects close to the surface are preferably shown in red, while the objects further from the surface and less at risk are shown in green or blue.  
           [0013]    A further possibility for graphically differentiating the located objects depending on their particular depth is to display the located objects that are within a certain depth as blinking in order to draw the operator&#39;s attention to them. The blinking frequency of the depicted objects can increase as the depth of the objects decreases, in order to bring particular attention to objects that are close to the surface and, therefore, particularly at risk.  
           [0014]    Furthermore, a variant of the invention also provides an acoustic signal generator that emits a warning signal in certain cases. This can be desirable, for example, when the depth of a located object is within a specified value range about which the operator should be alerted in particular. An acoustic warning signal of this type is usually emitted only when objects close to the surface are located that are particularly at risk. The value range can be stored permanently in the position finder, and/or it can be designed to be adjustable by an operator.  
           [0015]    Preferably, the surface of the object under examination is also depicted in the image section in order to permit rapid orientation by the operator in the image section. When a flat building wall is being scanned, a simple line can be displayed for this purpose.  
           [0016]    Within the framework of the invention, it is preferable to also include markings in the image section that represent the current position of the position detector and/or the edges of the housing of the position detector. In this manner, it is possible to easily match the object positions displayed in the image section with the actual positions of the objects in the building wall.  
           [0017]    The same purpose is served by the ability that is possible within the framework of the invention to include a graphic display of the current position of the position detector.  
           [0018]    In the preferred embodiment of the invention, the displayed objects, the depiction of the surface of the object under examination, the depth scale and/or the unit of measure of the depth scale are displayed in the image section in fixed positions, while the position detector moves during the scanning function and is therefore displayed in the image section as well, always in its current position.  
           [0019]    The position data provided by the position detector usually enable a statement only about an individual point on the surface of the building wall. The position detector is therefore preferably moved linearly over a line section on the surface of the building wall, in order to pick up the desired image section. To identify the area of the image section that has not yet been scanned, a variant of the invention provides that the area of the image section that has already been scanned is depicted graphically differently.  
           [0020]    A possibility for a graphic differentiation of this type is to show the previously scanned region of the image section in white and the region of the image section that has not yet been scanned in gray.  
           [0021]    Preferably, the depicted image section is updated continually or at specified time intervals during the scanning function, so that the image section that is displayed always corresponds to the current position of the position detector.  
           [0022]    Within the framework of the invention it is further possible to include additional information about the operating state of the position finder in the image section or to display it next to the image section.  
           [0023]    It was mentioned hereinabove that, with the position finder according to the invention, the image section through the object to be examined is displayed already while the location detection procedure is being carried out. To accomplish this, the position detector in the position finder according to the invention is connected via an evaluation unit with a graphic display unit, and the connection is a real-time connection that permits a current display of the result of the location detection. The term “real-time connection”, within the framework of the invention, is not limited to connections with which a time delay does not occur between the detection of the position signals and their depiction on the display unit, since signal transmission paths experience delay, in principle, due to response time. The team “real-time connection”, within the framework of the invention, therefore includes connections with which the time delay between detection of the position signals by the position detector and their depiction on the display unit is so small that the image on the display unit essentially reflects an image section through the object under examination at the current position of the position detector.  
           [0024]    Preferably, the image section depicted by the display unit of the position finder contains a graphic reproduction of the current position of the position detector, the current position of the center line of the position detector and/or the current position of an outer line of the position detector. This advantageously makes it easier for the operator to find his spacial orientation in the image section that is displayed.  
           [0025]    For the same purpose, the image section that is displayed preferably contains a graphic depiction of a surface of the object under examination, a depth scale, the unit of measure of the depth scale, and/or objects located in the object to be examined.  
           [0026]    Preferably, specified graphic patterns are provided to depict objects in the image section. The objects are therefore not depicted in the image section in accordance with their signal patterns that were actually measured, but in idealized form in accordance with the graphic patterns or symbols. This advantageously makes the depicted image section clearer and more understandable. The graphic patterns can be stored in a memory located in the position finder or in a memory located outside the position finder, whereby the memory located outside the position finder could be connected with the position finder via a radio interface, for example.  
           [0027]    The display unit is preferably an LED display, an LCD display, a cathode ray tube, a plasma display, a VFD display, or an OLED display, although the invention can also be realized with other types of display units.  
           [0028]    Furthermore, an additional acoustic and/or optical signal generator is provided, in order to generate an indication signal.  
           [0029]    Finally, it should be mentioned that the invention is not limited to certain location detection methods. 
       
    
    
     SUMMARY OF THE DRAWINGS  
       [0030]    Other advantageous further developments of the invention are characterized in the dependent claims or they are explained in greater detail hereinbelow together with the description of the preferred embodiment of the invention, with reference to the figures.  
         [0031]    [0031]FIG. 1 is a perspective view of a building wall and a position finder according to the invention,  
         [0032]    [0032]FIGS. 2 a ,  2   b  are various image sections of the building wall that were generated using the method according to the invention, and  
         [0033]    [0033]FIG. 3 is a simplified block diagram of a position finder according to the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0034]    The perspective illustration in FIG. 1 shows a building wall  1  with a water pipe  2  that can be located using a position finder  3  according to the invention in order to prevent damage to the water pipe  2  by drilling in the building wall  1 .  
         [0035]    To accomplish this, the position finder  3  is guided in linear tracks over the surface of the building wall  1 , each linear track generating an image section of the building wall  1 , as shown in FIGS. 2 a  and  2   b.    
         [0036]    The location detection method used by the position finder  3  is based on the response-time measurement of a signal from the position finder  3  that is penetrating the building wall  1  and is reflected on the water pipe  2 . Location detection methods of this type are known in general, so a detained description of the location detection method will not be provided hereinbelow.  
         [0037]    To display the result of the location detection, the position finder  3  has an integrated LCD screen  4  on which the image sections shown in FIGS. 2 a  and  2   b  are displayed.  
         [0038]    The image sections are displayed already while the individual line sections are being scanned, and it is updated continually, so that the image section shown on the LCD screen  4  corresponds to the current position of the position finder  3  at all times. This makes it easier for the operator to match the position of the objects inside the image section with the actual position of the object located in the building wall  1 .  
         [0039]    It shall now be explained with reference to FIGS. 2 a  and  2   b  how the image sections are depicted on the LCD screen  4  of the position finder  3 .  
         [0040]    [0040]FIG. 2 a  shows an image section through the building wall  1  during the process of scanning a line section on the building wall  1  when a region  5  on the line section has already been scanned and a further region  6  on the line section has not yet been scanned. The two regions  5 ,  6  of the image section are therefore depicted graphically differently in order to inform the operator about the progress of the scanning procedure and the current position of the position finder  3  on the line section. The region  5  that has already been scanned is shown in white, and the region  6  that has not yet been scanned is shown in gray.  
         [0041]    Furthermore, the surface of the building wall  1  is displayed at the bottom of the image section in the form of a baseline  7 , which makes it easier for the operator to find his orientation within the image section.  
         [0042]    This is enhanced by the inclusion of a graphic symbol  8  for the position finder  3 . The graphic symbol  8  is always displayed in the center. In the example of an image section shown in FIG. 2 a , a graphic symbol  12  of a detected object is displayed in the LCD screen  4  in the position that corresponds to its position in the building wall  1  relative to the position finder  3 . As an example, FIG. 2 a  shows an object located to the left of the position finder  3 . If the position finder  3  is moved to the left, the graphic symbol  12  moves in the LCD screen  4  in the direction of the graphic symbol  8  of the position finder  3 . If the graphic symbol  12  of the object is located directly above the graphic symbol  3  of the position finder  3 , the position finder  3  is located directly over the object, and the position of the object can be determined unequivocally using a marking notch—that is not shown in greater detail—on the position finder  3 .  
         [0043]    Furthermore, a centerline  9  that corresponds to the center of the position finder  3  is displayed in the image section in order to permit an exact determination of the position of an object in the building wall  1 .  
         [0044]    Outer lines  10  that depict the lateral edges of the housing of the position finder  3  are displayed for the same purpose.  
         [0045]    The objects detected by the position finder  3 , such as the water pipe  2 , are displayed in the image section in the form of standardized graphic symbols  12 . The graphic symbols  12  are situated correctly in the image section in accordance with their actual position in the building wall  1 .  
         [0046]    A depth scale  13  is included at the side in the image section to simplify spatial orientation. This enables the operator to read the depth of the located objects or a drilling depth derived therefrom immediately and without having to perform complex calculations, by referring to the graphic symbols  12 .  
         [0047]    The position finder  3  according to the invention is suited to detecting the location of objects at various depth ranges, so an additional display  14  is included in the image section that indicates the unit of measure of the depth scale  13 .  
         [0048]    If, using this principle of location detection, the wall areas behind the located objects are shaded by said objects, making it impossible to determine the position of other objects that may be located there, said shaded areas are shown as gray surfaces  15  in the image section, as is the region  6  that has not yet been scanned.  
         [0049]    Finally, FIG. 2 b  shows a finished image section after the position finder  3  has traversed one complete line section. The entire image section is therefore displayed in white to show that the scanning of the depicted image section is complete.  
         [0050]    Finally, FIG. 3 is a simplified block diagram of a position finder  16  according to the invention, that has a largely conventional design and will therefore be described only briefly hereinbelow.  
         [0051]    The position finder  16  enables the detection of the location of an object  17  in an object under examination, whereby the object under examination  18  can be a building wall, and the object  17  can be a pipe in the building wall, for example.  
         [0052]    To accomplish this, the position finder  16  has a position detector  19  that is placed, with a transducer head, on the surface of the object under examination  18  and sends a measurement signal  20  into the object under examination  18 . In the object under examination  18 , the introduced measurement signal  20  is reflected relatively strongly on the bounding surface of the object  17  to be located. It is then detected as a response signal  21  by the transducer head of the position detector  19 .  
         [0053]    The position detector  19  and the other components of the position finder  16  are controlled by a central control unit  22  that controls the introduction of the measurement signal  20  and the measurement of the response time.  
         [0054]    The position data captured by the position detector  19  are forwarded continually during the measurement via a real-time connection  23  to an evaluation unit  24  that calculates an image section through the object under examination  18  using the position data and the measured response times.  
         [0055]    This image section is reproduced continually during the measurement on an LCD display  26  via a real-time connection  25  by the evaluation unit  24 . The LCD display  26  depicts the image section in the manner described hereinabove and illustrated in FIGS. 2 a  and  2   b.    
         [0056]    Due to the real-time connections  23 ,  25  between the position detector  19 , the evaluation unit  24  and the LCD display  26 , the position finder  16  according to the invention makes it possible for the current position of the current image section through the object under examination  18  to be displayed already while scanning is being performed.  
         [0057]    Finally, the position finder  16  also has a speaker  27  that can be controlled by the control unit  22  to emit a warning signal. A warning signal of this type can be emitted, for example, when the location detection finds that the object  17  in the object under examination  18  is located very close to the surface, whereby the depth can be less than a specified minimum value.  
         [0058]    The embodiment of the invention is not limited to the preferred exemplary embodiments indicated hereinabove. Rather, a number of variants are feasible that also employ the means of achieving the object presented hereinabove in entirely different types of embodiments.  
       Reference Numerals  
       [0059]    [0059] 1  building wall  
         [0060]    [0060] 2  water pipe  
         [0061]    [0061] 3  position detector  
         [0062]    [0062] 4  LCD screen  
         [0063]    [0063] 5  scanned range  
         [0064]    [0064] 6  range not yet scanned  
         [0065]    [0065] 7  baseline  
         [0066]    [0066] 8  graphic symbol for position finder  
         [0067]    [0067] 9  center line of the position finder  
         [0068]    [0068] 10  outer line of the position finder  
         [0069]    [0069] 11  outer line of the position finder  
         [0070]    [0070] 12  graphic symbol for object  
         [0071]    [0071] 13  depth scale  
         [0072]    [0072] 14  display for unit of measure of the depth scale  
         [0073]    [0073] 15  hidden surface  
         [0074]    [0074] 16  position finder  
         [0075]    [0075] 17  object  
         [0076]    [0076] 18  object under examination  
         [0077]    [0077] 19  position detector  
         [0078]    [0078] 20  measurement signal  
         [0079]    [0079] 21  response signal  
         [0080]    [0080] 22  control unit  
         [0081]    [0081] 23  real-time connection  
         [0082]    [0082] 24  evaluation unit  
         [0083]    [0083] 25  real-time connection  
         [0084]    [0084] 26  LCD display  
         [0085]    [0085] 27  speaker