Abstract:
A comparison optical system ( 1 ) comprising several image-acquiring optical subsystems is disclosed. A bridge ( 3 ) mechanically and optically connects the optical subsystems to one another. Each of the image-acquiring optical subsystems possesses an XYZ stage ( 8   a   , 8   b ), movable in motorized fashion, on which a sample to be examined is placed. Also provided is a control unit which moves the XYZ stages ( 8   a   , 8   b ), movable in motorized fashion, synchronously in all three spatial directions. The synchronous motion of the XYZ stages ( 8   a   , 8   b ) can be switched on and off by the user.

Description:
RELATED APPLICATIONS 
     This application is a Continuation of U.S. application Ser. No. 10/694,690 filed on Oct. 28, 2003, which in turn claims priority to European Patent Application No. EP 02 102 514.3 filed on Oct. 31, 2002, both of which are incorporated herein by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention concerns a comparison optical system. The invention concerns in particular a comparison optical system having several image-acquiring optical subsystems that are connected to one another via a bridge which mechanically and optically connects the several image-acquiring optical subsystems to one another. 
     BACKGROUND OF THE INVENTION 
     German Patent DE 30 06 379 discloses a defect inspection system for comparative inspection of a standard specimen and a test item. The test item and the standard specimen are on a common support, and both the standard specimen and the test item are imaged via optical means and combined so that a comparison is possible. 
     German Unexamined Application DE 41 03 457 describes a comparison microscope for viewing two similar specimens through two objectives, having a device which is configured for combining the two images for comparative viewing. Each of the two objectives is part of an individual microscope, a video mixing apparatus, to which the video signals of two video cameras acquiring the images from the microscopes are conveyed, being provided as the device for combining the two images. Synchronous displacement of the microscope stages has not been acknowledged. 
     U.S. Pat. No. 4,403,839 describes a comparison optical device that is embodied for simultaneous observation of two specimens. A bridge encompasses the optical means for combining the beam paths that are generated by the microscope or macroscope. Illuminating light is introduced into the system by means of the photo tube. The document does not mention how the individual specimens must be arranged on one or more stages. 
     These macroscopes or microscopes described above are used in corresponding systems, which are embodied as comparison microscopes or comparison macroscopes, for performing forensic comparative examinations. In a very well-known embodiment, two individual microscopes or individual macroscopes, connected to one another by a bridge, are used. The bridge contains an apparatus for combining the two individual images generated by the individual microscopes or macroscopes. Through a common tube arranged on the bridge, the operator of the comparison microscope or macroscope can view in superimposed fashion the images of specimens arranged on two different stages. Appropriate blocking of portions of the two samples corresponding to one another yields a composite image which makes possible a direct comparison, for example, of one sample half to the other sample half. 
     In forensic investigations, crime-solving often requires that an image of a first sample be compared to the image of a second sample in order to obtain more detailed information about the circumstances of a crime. 
     The specimens compared to one another are, for example, the impressions produced on cartridge cases by the firing pin of a weapon, in order to determine whether the same firearm was used in two or more crimes. 
     A further known application of optical comparison investigations consists in checking the authenticity of documents, especially banknotes, in order to determine whether they are counterfeit. 
     Lastly, crime-solving often requires comparing, for example, clothing fibers found at the crime scene to fibers of known articles of clothing, in order to obtain information about how a perpetrator was dressed at the time of a crime. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to create a comparison optical system that is configured in user-friendly fashion and provides reproducible results. 
     This object is achieved by way of a comparison optical system comprising:
         several image-acquiring optical subsystems   a bridge which connects the several image-acquiring optical subsystems mechanically and optically to one another,   an XYZ stage, movable in motorized fashion, is provided for each image-acquiring optical subsystem, and   a control unit for moving the XYZ stages in motorized fashion, synchronously in all three spatial directions.       

     The above object is as well achieved by a comparison optical system comprising:
         two macroscopes,   a bridge which connects the two macroscopes mechanically and optically to one another,   an XYZ stage, movable in motorized fashion, is provided for each macroscope, and   a control unit for moving the XYZ stages in motorized fashion, synchronously in all three spatial directions.       

     The above object is as well achieved by a comparison optical system comprising:
         two microscopes,   a bridge which connects the two microscopes mechanically and optically to one another,   an XYZ stage, movable in motorized fashion, is provided for each microscope, and   a control unit for moving the XYZ stages in motorized fashion, synchronously in all three spatial directions.       

     The invention has the advantage that each image-acquiring optical subsystem possesses a XYZ stage, movable in motorized fashion, on which a sample to be examined is placed. Also provided is a control unit that moves the XYZ stages ( 8   a ,  8   b ), movable in motorized fashion, synchronously in all three spatial directions. If the comparison optical systems are embodied as macroscopes, the control unit is embodied as a control and adjustment apparatus on which is provided an on/off switch with which synchronous displacement of the XYZ stages can be switched on and off. Synchronous displacement has the advantage that upon actuation of an actuation element for a motion direction of an XYZ stage, both XYZ stages are displaced in exactly uniform synchronous fashion. The macroscopes can likewise each have associated with them a remote control device that can be used for stage and focus control. It is also possible to activate the stage and focus control systems of the two remote control devices in such a way that a synchronous motion is possible. The comparison optical system can likewise be constructed from microscopes. In this case a remote control device is connected to each microscope and can be activated so as to make possible, for example by actuation of an actuation element of the remote control device, synchronous displacement of the XYZ stages that are mounted on the microscope stand. The structures present on the specimens to be examined are often larger in terms of dimension than the region which is visible in the eyepiece or with the attached camera. In order to allow the entire specimen to be compared, both XYZ stages must be shifted synchronously in the X direction, Y direction, and Z direction. With synchronous displacement it is possible to shift the two XYZ stages synchronously using only one X actuation element or Y actuation element or the Z fine displacement control for each of the X, Y, and Z axes respectively. This has the advantage that evaluation of the specimens to be examined is considerably improved. A prerequisite for synchronization is that at least the three axes of the XYZ stages be motorized. 
     Further advantageous embodiments of the invention are evident from the dependent claims. 
     The above and other features of the invention including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings: 
         FIG. 1  is a perspective view of a first embodiment of the comparison optical system, the optical subsystems being embodied as macroscopes; 
         FIG. 2  is a perspective view of a second embodiment of the comparison optical system, the optical subsystems being embodied as microscopes; and 
         FIG. 3  is a detail view of a control unit with which the XYZ stages of the comparison optical system are synchronously movable. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a comparison optical system  1 . In this embodiment, comparison optical system  1  comprises a first and a second macroscope  2   a  and  2   b  that are configured as image-acquiring optical subsystems. First and second macroscope  2   a  and  2   b  are mechanically and optically connected to one another via a bridge  3 . Bridge  3  possesses a viewing port  4  for a user, and a tube  5  having a connection  6  for a camera (not depicted). Viewing port  4  for the user can be configured pivotably in order to maintain an ergonomic working position for the user. Tube  5  can additionally possess a further connection  7  with which, for example, a second camera (not depicted) can be attached. A first XYZ stage  8   a  is associated with first macroscope  2   a . A second XYZ stage  8   b  is associated with second macroscope  2   b . A specimen to be compared (not depicted) is placed respectively on first and on second XYZ stage  8   a  and  8   b . In comparison macroscopy, both bullets and tools are assessed as specimens, and the traces left thereby are optically compared to one another and evaluated. This is done, in most cases, by splitting the image in the middle so that the specimen positioned on first XYZ stage  8   a  is visible in the left half, and the specimen positioned on second XYZ stage  8   b  is visible in the right half. 
     Bridge  3 , together with first and second XYZ stage  8   a  and  8   b , is mounted on a column  10  via a dovetail guide  11 . By vertical displacement of column  10 , bridge  3  is displaceable in the Z direction, or vertically, relative to the surface of XYZ stages  8   a  and  8   b . The movement of bridge  3  allows coarse focusing of the specimens, present on the two stages  8   a  and  8   b , whose structures are to be compared. Column  10  itself is joined to a base  12  which is substantially wider than column  10  in order to achieve sufficient stability and steadiness for comparison optical system  1 . Arranged between the first and on the second XYZ stage  8   a  and  8   b  is a control and adjustment apparatus  14  with which various functions of comparison optical system  1  can be adjusted or modified. Control and adjustment apparatus  14  possesses several actuation elements (see  FIG. 3  for description) with which various functions of comparison optical system  1  can be actuated. It is self-evident that control and adjustment apparatus  14  depicted in  FIG. 1  can be variously embodied. 
     The two XYZ stages  8   a  and  8   b  are displaceable in the X direction, Y direction, and Z direction by way of several motors  16 . A first and a second remote control device  18   a  and  18   b  can moreover also be associated with comparison optical system  1 . In this embodiment, the first and a second remote control device  18   a  and  18   b  are each connected to comparison optical system  1  via a cable  19 . Remote control devices  18   a  and  18   b  each possess a plurality of actuation elements  24  that can be assigned for various motorized functions of comparison optical system  1 . It is self-evident that the connection can assume any technical configuration, for example radio, infrared, etc. Comparison optical system  1  can additionally have associated with it a PC  20  that, via an RS232 cable or USB cable  21 , supplies control signals to comparison optical system  1  and receives image data or settings data from comparison optical system  1 . The image data are displayed to the user on a monitor  22  that is connected to PC  20 . The current settings data of comparison optical system  1  can also be displayed to the user on monitor  22 . 
       FIG. 2  is a perspective view of a second embodiment of comparison optical system  1 , the optical subsystems comprising, in this embodiment, a first and a second microscope  30   a  and  30   b . Elements that correspond to the elements in  FIG. 1  are labeled with the same reference characters. First and second microscope  30   a  and  30   b  are connected to one another via a bridge  3 . Each microscope  30   a  and  30   b  comprises a stand that comprises a base  32 . Base  32  is subdivided into three main segments, made up of a transverse main segment  34 , a stand column segment  36 , and a stand foot segment  35 . An XYZ stage  8   a ,  8   b  is mounted on stand column segment  36 . Each microscope  30   a  and  30   b  is equipped with a transmitted-light illumination system and an incident-light illumination system (both not depicted). 
     Stand foot segment  35  is convexly curved in the region facing toward stand column segment  36 , and possesses a display  40  in convexly curved region  37 . Display  40  can also be embodied as a touch screen which allows the user to make parameter inputs and call certain measurement methods therewith. If display  40  is not embodied as a touch screen, current settings data of the respective microscope  30   a  or  30   b  are then visually presented via display  40 . Additionally mounted on each microscope  30   a  and  30   b  is a respective drive knob  42  which, for example, displaces XYZ stage  8   a  or  8   b  associated with each microscope  30   a  or  30   b  vertically (in the Z direction). It is likewise conceivable additionally to assign other functions to drive knob  42 . Multiple actuation elements  44  with which microscope functions can also be switched are provided in the region around drive knob  42 . The microscope functions are, for example, filter changing, aperture selection, revolving turret movement, etc. 
     Bridge  3  is attached to connecting element  50   a  and  50   b  of each microscope  30   a  and  30   b . Analogously to  FIG. 1 , bridge  3  possesses a viewing port  4  for a user, and a tube  5  having a connection  6  for a camera (not depicted). Viewing port  4  for the user can be configured pivotably in order to maintain an ergonomic working position for the user. Both XYZ stages  8   a  and  8   b  are displaceable in the X direction, Y direction, and Z direction by way of several motors  16 . Analogously to  FIG. 1 , first and second remote control device  18   a  and  18   b  are also associated with comparison optical system  1 . These are each connected via a cable  19  to comparison optical system  1  or to PC  20 . It is self-evident that the connection can assume any technical configuration, for example radio, infrared, etc. A display  22  is additionally associated with PC  20 . 
       FIG. 3  is a detail view of control and adjustment apparatus  14  of  FIG. 1 , with which XYZ stages  8   a  and  8   b  of the comparison optical system are synchronously movable. Control and adjustment apparatus  14  encompasses a plurality of adjusting elements for comparison optical system  1 . Provided on a front side  14   a  of control and adjustment apparatus  14  is a switch  60 , actuation of which causes a vertical displacement of column  10  ( FIG. 1 ). This results in coarse focusing on the specimens that are present on XYZ stages  8   a  and  8   b  of comparison optical system  1  of  FIG. 1 . Directly above switch  60  is an on/off switch  61  for synchronous displacement of the two XYZ stages  8   a  and  8   b . To the left of switch  60  is an X actuation element  62   a  for displacing first XYZ stage  8   a  in the X direction. To the right of switch  60  is an X actuation element  62   b  for displacing second XYZ stage  8   b  in the X direction. Provided above X actuation element  62   a  is an adjustment element  63   a  for an illumination system, with which the light intensity of an external light source (not depicted) can be modified. Similarly, above X actuation element  62   b  is an adjustment element  63   b  for an illumination system, with which the light intensity of an external light source (not depicted), whose light is directed onto second XYZ stage  8   b , can be modified. 
     In  FIG. 3 , only a first lateral surface  14   b  of control and adjustment apparatus  14  is depicted visibly. On first lateral surface  14   b  is a Y actuation element  64   b  for displacing second XYZ stage  8   b  in the Y direction. Also provided on first lateral surface  14   b  is a Z fine displacement control  65   b  for second XYZ stage  8   b  in the Z direction. A Z fine displacement control  65   a  for first XYZ stage  8   a  is provided on second lateral surface  14   c.    
     Control and adjustment apparatus  14  furthermore possesses a top surface  14   d  on which are mounted several actuation elements  70 ,  71 ,  72 ,  73 ,  74 ,  75 , and  76  which are provided for modification of the image depiction. Actuation element  70  serves to generate a superimposed image, the image of the specimen on first XYZ stage  8   a  being overlaid on the specimen on second XYZ stage  8   b . Actuation element  71  serves to generate a side-by-side depiction of the specimen on first XYZ stage  8   a  next to the specimen on second XYZ stage  8   b . Actuation element  72  serves to generate a depiction of the image of the specimen on first XYZ stage  8   a . Actuation element  73  serves to generate a depiction of the image of the specimen on second XYZ stage  8   b . Actuation element  74  is used for manual aperture matching. Actuation element  75  is used for manual lateral shifting of the apertures. Actuation element  76  is used for secondary magnification of the specimens to be depicted. In a particular embodiment, a 1.5× magnification is provided. 
     An on/off switch  61  for synchronous displacement of the two XYZ stages  8   a  and  8   b  is configured in such a way that the functioning of the control elements is coupled, so that the previously independent X actuation elements  62   a  and  62   b , Y actuation elements  64   a  and  64   b , and Z fine displacement controls  65   a  and  65   b  for each individual XYZ stage  8   a  and  8   b  act synchronously on both XYZ stages  8   a  and  8   b . Once the two XYZ stages  8   a  and  8   b  have been adjusted, the structures to be investigated are compared. These structures are often larger in terms of their dimensions than the region that is visible in the eyepiece or with the attached camera. To allow the entire specimen to be compared, both XYZ stages  8   a  and  8   b  must be shifted synchronously in the X direction, Y direction, and Z direction. It is thereby possible, using only one X actuation element or Y actuation element or the Z fine displacement control for each of the X, Y, and Z axes respectively, to displace the two XYZ stages  8   a  and  8   b  synchronously in order thereby to improve the evaluation of the specimens being investigated. In addition, the ergonomics of the entire comparison optical system  1  is considerably improved. A prerequisite for synchronization is motorization of the three axes of XYZ stages  8   a  and  8   b . This applies both to macroscopes  2   a  and  2   b  or microscopes  30   a  and  30   b  that are connected by bridge  3 . 
     In addition to control and adjustment apparatus  14  for macroscopes  2   a  and  2   b , the latter also have associated with them a first remote control device and second remote control device  18   a  and  18   b . Once macroscopes  2   a  and  2   b  or microscopes  30   a  and  30   b  have been adjusted in conventional fashion, the functioning of the actuation elements is coupled, by way of a button or a command from the PC (via RS232, USB, etc.), in such a way that upon actuation of any actuation element or the Z fine displacement control for a direction, both XYZ stages are moved synchronously. It is now possible, for example via X operating element  62   b  of second XYZ stage  8   b  and X operating element  62   a  of first XYZ stage  8   a , to move both XYZ stages  8   a  and  8   b  synchronously in the X direction. The same applies to the axes in the Y and Z directions. 
     As with comparison optical system  1  in which macroscopes  2   a  and  2   b  are used, this function can be switched on by way of the built-in electronic system. When two microscopes  30   a  and  30   b  made up of two independently functioning stands are combined with a bridge  3 , electronic synchronization of XYZ stages  8   a  and  8   b  is then accomplished via interfaces or PC  20 . As depicted in  FIG. 2 , first microscope  30   a  and second microscope  30   b  have respectively associated with them a first remote control device  18   a  and a second remote control device  18   b , which have actuation elements  24  for the X direction, Y direction, and Z direction of each XYZ stage  8   a  and  8   b . As with macroscopes  2   a  and  2   b , the synchronization makes it possible to control both XYZ stages  8   a  and  8   b  of microscopes  30   a  and  30   b  synchronously using only one remote control device  18   a  or  18   b.    
     While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.