DE102010018291B4 - Navigation system and X-ray system - Google Patents

Abstract

Navigation system (8), with at least one camera (10a, b), and with at least one navigation marker (12a, b) with at least four identifiable by the camera (10a, b) in at least one camera image (20a, b) marker elements (22a , b), wherein three of the marker elements (22a, b) define a plane (26) and the fourth marker element (22a, b) lies outside the plane (26) with a reference to the position (23) of the images of the marker elements (22a , b) in the camera image (20a, b) the relative position (z) of the navigation marker (12a, b) to the camera (10a, b) determining evaluation unit (16), wherein the camera (10a, b) is an endoscopic or laparoscopic camera ,

Description

The invention relates to a navigation system and equipped with a navigation system X-ray system.

Patients are referred to as medical measures e.g. performed surgical procedures. Hereby, it will be appreciated by the performers, e.g. Surgeons, more and more desirable to get navigation assistance. This means that both the position and orientation of the patient or his organs, bones or the like, as well as positions and orientations of instruments, medical aids, medical devices, etc. are known in a three-dimensional coordinate system. In doing so, it may be desirable to have the positions absolute, e.g. in the operating room to know, or at least to know the relative positions of patient and instrument. If the corresponding positions and orientations are known, e.g. a so-called navigation-assisted surgery are performed.

The problem of determining positions and orientations in space and their assignment to patient or image data is therefore known from navigation-assisted surgery. To solve the following navigation systems are known:

Navigation markers - or "markers" for short - are attached to the objects to be located. In this case, several marker elements are combined in a geometrically fixed arrangement on a support or tripod to form a marker. The use of active marker elements in the form of light-emitting diodes or passive marker elements in the form of infrared-reflecting spheres is known. Such markers are e.g. attached to a surgical instrument, the relative position between marker and instrument or e.g. whose working tip is known or given. This creates a unique geometric relationship between e.g. the instrument tip and the marker. The position and orientation of the marker in turn is detected by optical stereo cameras. Geometric triangulation defines location and direction, i. Position and orientation of the marker in the reference frame of the stereo camera determined. A known stereo camera has e.g. two CCD cameras and is known as the "Polaris" system from NDI. Markers require 3 marker elements each. With two markers, five degrees of freedom can be determined, namely three positions and two angles. However, a rotation about the connecting axis of the two markers can not be determined, whereas the marker arrangement is invariant. A third marker thus serves to determine a sixth degree of freedom and to distinguish different markers.

Out DE 102 06 193 C1 . DE 11 2007 001 214 T5 . DE 102 46 147 A1 . WO 2007/128 377 A1 and US 2005/0 201 613 A1 are optionally known for navigation systems extracorporeal cameras known. WO 2009/047 335 A1 describes a CAD (Computer Aided Design) model for intelligent and automatic object recognition.

As an alternative to the aforementioned optical navigation, a so-called electromagnetic navigation is known by corresponding navigation systems. Here is an electromagnetic sensor coil as a navigation marker. The optical camera is replaced by a field-generating field generator. In such a navigation system position and orientation of the sensor coil in the field of the field generator and thus determined in the coordinate system. The sensor coil as a navigation marker can be attached to an object again, but e.g. also be integrated in a tool or in an implant.

With regard to the X-ray system, the invention is concerned with the radiographic support of surgical procedures, again in connection with the positioning of surgical instruments or implants and their insertion into medical image data, e.g. be generated by the X-ray system. Known here is e.g. the combination of an X-ray machine and the above-mentioned navigation system with optical stereo camera in the form of the system "C-Nav" of the company CAS-Innovations or similar systems of the company Brainlab.

Alternatively, from the DE 100 49 103 A1 - For example, as a so-called "CAMC" system (camera augmented mobile C-arm) from the company Siemens - an X-ray device is known in which an optical video camera is firmly integrated into the X-ray device that their line of sight corresponds to that of the X-ray image of the X-ray device. This system allows a geometrically exact superimposition of the 2D X-ray image obtained eg from a C-arm with the live camera image of the video camera to support surgical procedures. First, an X-ray image is taken simultaneously with a video image of the patient. The video image then shows the visible surface of the patient and instruments available in the surgery allowance. Both images, X-ray image and video image, can be faded into each other, that are highlighted according to the user's choice different levels.

For example, an instrument placement, i. the choice of a puncture site on the patient is then later alone on the basis of the live video image of instrument and patient, superimposed with the pre-recorded video image.

To check whether a new X-ray image has to be made, for example, a marker is glued to the outside of the patient, which is visible in the video image and in the X-ray image. If the marker in the live video image shifts compared to the position in the previously recorded X-ray image, a patient's movement is assumed and a new X-ray image is taken.

The mentioned navigation systems are associated with a high expenditure on equipment. The CAMC system does not provide actual three-dimensional position and orientation determination of markers in the sense of the above-mentioned navigation systems.

The object of the present invention is to specify an improved navigation system and an improved x-ray system.

With regard to the navigation system, the object is achieved by a navigation system with a camera and with a navigation marker, wherein the navigation marker comprises at least four marker elements. The camera delivers a camera image during operation, the camera and marker elements being matched to one another such that the four marker elements can be detected and identified in the camera image. In this context, "detectable" means that they can be recognized in the camera image to the extent that their position in the camera image can be detected. In other words, the location of the image of the marker elements in the camera image, e.g. relative to the image boundaries. "Identifiable" means that the image of each marker element in the camera image can also be assigned to the corresponding marker element. The marker is designed such that three of the marker elements define a plane and the fourth element lies outside of said plane. In order for three marker elements to define a plane, two marker elements define a straight line, with the third marker element lying outside the line. In other words, the four marker elements must not be in one plane.

The navigation system also includes an evaluation unit. This is designed so that it determines the relative position of the marker to the camera based on the location of the marker elements, or their images, in the camera image.

According to the invention, the camera is an endoscopic or laparoscopic camera. A corresponding navigation system could thus also be used by a camera of an endoscopy capsule in a magnetic capsule endoscopy (MGCE). Such a freely movable in the patient capsule endoscope is eg from the DE 101 42 253 C1 known. Inserts of the navigation system within a patient, ie within the body, are also possible with such a camera. In particular, in combination with navigation markers printed on endoscopic instruments, for example, instruments introduced into the patient together with the camera can be located in their relative position to the endoscopic camera. Especially in this embodiment, therefore, an optical navigation within a patient is possible, which was impossible with previous optical navigation systems or due to the required two cameras in the sense of a stereo camera was previously impractical. The camera is, for example, a camera operating in the visible or infrared light range, which, in particular in the latter case, is combined with a corresponding infrared light source and infrared-reflecting marker elements. In particular, in conjunction with an infrared camera is usually an infrared light source, for example, around the camera lens, mounted. Such an arrangement is known, for example, as a passive camera system or passive camera from the company Polaris, which works with passive markers, for example reflective beads. In contrast, active systems use active markers, ie those that actively emit light, eg with the help of actively controlled LEDs, which are detected by the camera. The navigation markers or marker elements are then equipped, for example, with an infrared-reflecting surface. The infrared camera then has an infrared-sensitive detector. Also here are additional infrared light sources, eg on an X-ray C-arm, conceivable.

In other words, according to the invention, e.g. on a surgical instrument or implant, a marker with n≥4 recognizable recognizable by the camera in an image, so e.g. optically visible, marker elements attached. The marker elements in this case have a defined and known spatial structure or relative arrangement to one another. In other words, distances and angles of the marker elements to one another are known within the marker, the markers not being allowed to lie all in one plane. In contrast to the stereo camera in known navigation systems, the markers are identified by a single, fixed or mobile e.g. recorded in a treatment room, video camera recorded. The camera of the navigation system may e.g. be permanently installed on a device or in a treatment room or mobile, e.g. be stored on an adjustable tripod. The camera is thereby corrected for existing geometrical aberrations and calibrated for its imaging properties (e.g., for an available zoom).

When using n≥4 marker elements per navigation marker or their detection in the camera image, the position and orientation of the navigation marker, ie its position, can be determined and determine orientation in the coordinate system of the camera by a simple object recognition in the video image. This is done by the evaluation unit. If the navigation marker is firmly attached to, for example, an instrument in a known relative position and the geometry of the instrument is known, then the transformation from the marker to the surgically active instrument tip can be clearly defined or determined by a calibration procedure.

Image processing of the camera image enables rapid recognition of the navigation marker and thus real-time position measurement, since the determination of the position of the marker is effected by simple geometric calculations. The recognition, i. Determination of the position and orientation of the navigation marker can then take place in real time by continuous recording of camera images and their evaluation, so that with the aid of the camera a continuous tracking of the marker and thus e.g. the instrument concerned. This only requires a direct and uninterrupted line of sight between the camera and the marker.

In contrast to the navigation or location determination of the position of a marker by a stereo camera, the procedure used according to the invention with a single camera may be somewhat less accurate, but is sufficient for most applications. The omission of the second camera must be compensated by using a fourth marker element per marker compared to the stereo camera; There are three markers sufficient. In the present method, at least four marker elements must be used, with more than four marker elements e.g. increase the accuracy or make redundancies usable. In the known stereo camera, two marker elements are sufficient if it is not important to determine the angle of rotation about its own axis, ie only five degrees of freedom (DoF, Degrees of Freedom) are required. If all parameters, ie six DoFs are to be determined, then at least three marker elements are necessary.

The markers or marker elements should be kept sufficiently small so that they are still clearly recognizable in the camera image, but are not so large that they are e.g. obscure significantly anatomical structures of the patient. Thus, a corresponding observation of the patient can be carried out simultaneously in the camera image, e.g. in the context of the o.g. CAMC process.

In a preferred embodiment of the invention, the marker elements within the navigation marker differ in terms of their color and / or geometry. When the different marker elements, e.g. Spheres, color or geometrically designed differently and a color camera used, the assignment of the images of the respective marker elements to the actual marker element is significantly simplified. Using the geometry as a distinguishing feature is basically possible, but difficult. The center point of the marker element must be determinable from each projection direction, which is particularly simple or unambiguously possible, in particular in the case of a spherical shape.

In a further embodiment, the navigation system comprises at least two navigation markers. These then differ with respect to the color and / or geometry and / or geometric relative arrangement of their marker elements. Thus, the different navigation markers in the camera image can be easily distinguished. Different instruments may e.g. be distinguished by different navigation markers, if the corresponding marker arrangements are designed differently and simultaneously tracked by the camera. In other words, the distinction in color and geometry may differ both within a navigation marker and between different navigation markers.

In conjunction with the o.g. Infrared camera could include various marker elements e.g. be equipped with different reflective infrared filters to facilitate identification of the marker element or the navigation marker in the camera image. For the use of different infrared filters, the camera could then also be equipped with a plurality of infrared chips, which are respectively matched to different infrared filters. Cameras are also conceivable which contain both sensor chips in the visible and in the infrared range, ie at least two chips.

In a preferred embodiment of the navigation system, the marker elements are formed by being applied as marks to a surface of the navigation marker, e.g. printed or glued on. Here, the geometric surface design of the navigation marker must then ensure that the marker elements - as explained above - do not lie in one plane. In other words, the navigation marker is then a spatially-shaped entity having a corresponding surface that contains the marker elements as e.g. has colored imprint. Because of the requirement that the markers must always be visible from a camera, this variant is possible, but may be difficult. Again, an education of the marker elements as an infrared reflecting surface is conceivable.

In particular, in a particular embodiment of this embodiment, the navigation marker may form an integral part of, for example, an instrument or may even be formed by the instrument. The marker elements are then printed directly on the surface of the instrument. Thus, the instrument or its surface simultaneously forms the navigation marker. A navigation marker as a separate component is no longer necessary.

In a further embodiment of the invention, the navigation system comprises at least one second camera, which has its own evaluation unit. This means that strictly speaking, only a single evaluation unit in the navigation system for multiple cameras can be present. The decisive factor is that the camera image of each individual camera is evaluated individually and the relative position of the marker for each camera is determined from each individual camera image. This represents a significant difference to the stereo camera according to the prior art, since in each case at least two cameras are necessary to be able to determine a single position of a marker at all.

By using a second or more additional cameras e.g. At other locations in the treatment room, all of which are aligned with the treatment area, ie the potential location of navigation markers, the problem of the necessary line of sight between camera and marker can be alleviated. It should be emphasized that the several cameras not even in the sense of the above-mentioned stereo camera, i. work together in the sense of triangulation, but each camera for each as a single camera based on the image processing of the individual camera image determines the respective relative position of the marker in the coordinate system of the respective individual camera.

The relative positions of the individual cameras relative to one another can be determined particularly easily here. For this purpose, the cameras whose relative position is to be determined relative to one another simultaneously produce a camera image of the same marker. Since the respective relative position of the camera to the marker is known from each individual camera image, the relative position of the cameras relative to one another is also known.

In particular, such a navigation system can therefore be used "in vivo".

With regard to the X-ray system, the object is achieved by an X-ray system having an X-ray device which delivers an X-ray image during operation and a navigation system described above. The camera of the navigation system is in this case integrated into the x-ray device, which coincides with its direction of view with the imaging direction of the x-ray device. In other words, the camera image and X-ray image form a patient in the X-ray device from the same viewing direction and with the same projection geometry. The central beam of the X-ray machine and the central imaging axis of the camera coincide. Viewing direction - and possibly also the viewing angle - both images are the same or at least similar. The viewing angle of the camera can also be greater than the viewing angle of the x-ray machine.

In particular, e.g. Any X-ray device with the above-mentioned CAMC functionality - there specifically for a C-arm - equipped. The CAMC system may e.g. work together with a mobile or stationary X-ray C-arm, a mobile X-ray system, e.g. Siemens "Mobilett" or digital or analog radiography systems.

For example, For example, an existing CAMC camera in the X-ray system can be used as a camera of the above-mentioned navigation system and retrofitted with a corresponding evaluation unit. Then there are the above mentioned navigation markers with marker elements.

In the X-ray system according to the invention, the use of the camera thus enables both CAMC functionality, ie the possibility of image superimposition between a camera or video image and a 2D X-ray projection image. In other words, an integration into CAMC takes place. At the same time, thanks to the use of the camera in the navigation system, the above-described 3D navigation, ie location and position determination of components, is possible with the aid of navigation markers.

The calibration of the coordinate systems of the camera and X-ray imaging takes place once during the production of an X-ray apparatus according to the invention, as is usual in CAMC systems. A further calibration at a later date is no longer necessary here.

Thus, for example, the currently known CAMC function for operation support can be significantly expanded by the invention. The invention integrates a simple navigation method into the X-ray system, which functions both with video support and without video support in both two or three dimensions, since the acquired location information of the markers is present in 3D. The work without video support works, for example, if a 3D data set was previously generated and the 2D X-ray image was superimposed on the 3D data set by means of 2D / 3D registration.

By a dual function of the camera as a supplier of the video image for the CAMC application on the one hand and to obtain the navigation information in the navigation system on the other hand, an inherent or simple registration between X-ray and navigation functionality and online monitoring of the overlay quality is possible. Online monitoring succeeds e.g. by means of a marker, which is glued on the patient.

The integration of the navigation system allows a significant expansion of the functionality of a previous X-ray system.

In a preferred embodiment of the invention, the X-ray device is a C-arm X-ray device. Thus, the navigation function is actually integrated into an original CAMC system.

In a further embodiment of the invention, the X-ray system has an evaluation unit, which displays a location mark correlated with the navigation marker in the X-ray image with the correct position between the marker and the camera determined by the navigation system. The registration between the camera image and the X-ray image, which is inherent or mandatory in a CAMC X-ray device anyway, can be used in this way. Thus, the navigation information obtained with respect to the markers or connected instruments based on the camera registered for the x-ray system can thus also be superimposed or superimposed on the x-ray image. This is useful when e.g. Instruments are already inside the patient, as in the previous CAMC then e.g. the instrument tip in the patient was no longer visible in real time, as long as no X-ray image was taken. Of course, the markers recognizable in the camera must remain outside the patient in their field of vision.

If pre-operative or intraoperative 2D or X-ray 3D image data are available from the patient, they can also be registered on the X-ray machine. The 3D positions of the markers or instruments currently obtained by the navigation system can then be converted into the respective image data, e.g. the preoperative 3D volume will be transferred. 2D X-ray images currently obtained with the X-ray system can also be used as a monitor for possible object movements, e.g. Patient movements are used. For this, e.g. - As usual with CAMC procedures - a marker on the skin surface of the patient, glued and its movement are tracked by the camera.

If the camera of the navigation system is not attached and registered directly to the C-arm as usual with CAMC, then the procedure just described can be carried out as with a classic navigation. In the treatment room, the inventive singular video camera is used instead of a classically known stereo navigation camera. The - if necessary, several - video cameras can then be placed strategically favorable, and the registration as in the classical optical navigation are performed.

With the appropriately equipped X-ray system, e.g. If the X-ray machine is a C-arm, second or further X-ray images of a patient can be taken at different projection angles. For example, Then there are two 2D X-ray images of a patient from lateral and AP (anteroposterior) position. Thus, the current instrument position determined by the navigation system can be displayed in both X-ray images and thus immediately in a second level. The only prerequisite is that the projection geometry of the second projection direction is also known. The determination of the projection position may e.g. via an angle encoder in an isocentric C-arm. This is a significant advance over pure CAMC functionality because quasi-3D information, e.g. about the penetration depth of an instrument in a patient and can also be visualized.

• 1 ein erfindungsgemäßes Navigationssystem,
• 2 ein Kamerabild des Navigationssystems aus 1,
• 3 einen Navigationsmarker aus 1,
• 4 ein erfindungsgemäßes Röntgensystem,
• 5 Kamera- und Röntgenbilder des Röntgensystems aus 4.

For a further description of the invention reference is made to the embodiments of the drawings. They show, in each case in a schematic outline sketch:

• 1 an inventive navigation system,
• 2 a camera image of the navigation system 1 .
• 3 a navigation marker 1 .
• 4 an inventive X-ray system,
• 5 Camera and X-ray images of the X-ray system 4 ,

1 shows a patient 2 on a patient table 4 on which surgery is currently being performed. This is done by means of a medical instrument 6 or its trained as a tool tip 7 , The procedure is performed as navigation-assisted surgery. This is served by a navigation system 8th according to the invention.

The navigation system 8th includes a camera 10a in the form of an optical video camera, as well as two navigation markers 12a B. The navigation marker 12a is fixed, so in known relative position on the patient 2 fixed so that every movement of the patients 2 also forcibly to a movement of the navigation marker 12a leads. The navigation marker 12b is firmly on the instrument 6 attached, so that every movement of the instrument 6 also in a movement of the navigation marker 12b reflected. In particular, the entire geometry of the instrument 6 , in particular the relative position of the tip 7 , in relation to the navigation marker 12b known. The navigation marker 12a serves as a reference and defines a coordinate system 14a , which serves as a reference or patient coordinate system. The navigation marker 12b on the other hand defines an instrument coordinate system 14b ,

About the patient 2 there is a room area, namely the operating area 13 in which there are instruments during the procedure 6 or navigation markers 12a , b, which are relevant to the intervention at this moment. The camera has a viewing direction 11a as a central image direction, central to the surgical field 13 is directed. The camera has a field of view 15a which covers the entire operating area 13 detected.

The navigation system 8th also includes an evaluation unit 16 which with the camera 10a or their image sensor 18 connected is. During operation of the navigation system 8th Now take the camera 10a over the image sensor 18 a camera picture 20a and transmits this to the evaluation unit 16 ,

The camera picture 20a is enlarged in 2 shown. In the camera picture 20 are respective images of the patient 2 , Patient table 4 and the two navigation markers 12a , b together with that of the instrument 6 to see. From the instrument 6 is only the outside of the patient 2 to see located part; the one in the patient 2 located part with the top 7 is in 2 indicated only by dashed lines, but not visible.

3 shows enlarged the navigation marker 12a , The navigation marker 12a has four marker elements 22a on, the navigation marker 12b four marker elements 22b , Two of the marker elements 22a define a straight line 24 in the room, so do not coincide. A third marker element 22a is arranged such that it is outside this line 24 lies and so together with the former two marker elements 22a a level 26 defined in the room. The fourth marker element 22a again lies outside this level 26 , The respective relative spatial position of the marker elements 22a each other describes their relative arrangement 30 , which for example for different navigation markers 12a , b is different to each other in the camera image 20 to be able to distinguish.

According to 1 now evaluates the evaluation unit 16 this in 2 shown camera image 20a As follows: First, the respective images of the marker elements 22a respectively. 22b recognized and with the respective marker elements 22a , b identified. The positions or positions 23 the images of the marker elements 22a respectively. 22b in the camera picture 20a are recorded.

A location 23 an image is characterized for example by the respective distances x and y of the image to the image edge of the camera image 20a , as in 2 shown.

For every navigation marker 12a and 12b then determines the evaluation unit 16 the location and orientation of the respective navigation marker 12a , b in the coordinate system 14c the camera 10a , In other words, transformation matrices become so between the coordinate systems 14a , b and the coordinate system 14c determined. The individual coordinate systems 14a-c are registered with each other in the right place. This is done with known, not further explained methods of image processing in real time.

In particular, so are the relative positions z _i and z _R between the coordinate systems 14a , b the navigation marker 12a , b and the coordinate system 14c the camera 10a determined. The relative positions Z _{I, R} describe in each case position and orientation, ie a reference point and a vectorial orientation of the coordinate systems 14a , b or the navigation marker 12a , b and thus of patient 2 and instrument 6 and its tip 7 in the coordinate system 14c ,

In particular, this is the relative position z _i the top 7 of the instrument 6 in the coordinate system 14c known, in which also the camera image 20a has been recorded. According to this information, an instrument tip 7 indicating placemark 28 in the camera picture 20a to be displayed.

1 shows in an alternative embodiment in dashed lines a second camera 10b whose line of sight 11b also on the surgery area 13 is aligned. The field of vision 15b thus completely covers the surgical area 13 , Through the other spatial arrangement of the camera 10b in the room or the angular deviation of the viewing directions 11a , b results in the following advantage: For example, if a surgeon's hand, not shown, interferes with the camera 10a and the navigation marker 12a so that this is in the camera image 20a the camera 10a is not visible, but he is in the camera image 20b the camera 10b visible, noticeable. The location tracking of the navigation marker 12a can be continued so continuously. A corresponding relative position z _i can therefore also between the navigation marker 12a and the camera 10b or their coordinate system 14d be determined. As well as the relative position of the camera coordinate systems 14c and 14d is known, are thus again all local contexts in the in 1 situation clearly known.

4 shows an inventive X-ray system 34 with an x-ray machine 36 in the form of a C-arm and the navigation system already explained above 8th , alternative to 1 Here is the medical procedure on the patient 2 performed with X-ray support. This is the x-ray system 34 an X-ray source 38 and in the patient table 4 an x-ray detector 40 integrated. With the help of the X-ray machine 36 can be on the patient 2 a certain area of space in an x-ray image 44 be imaged. The room area results from the X-ray cone 42 who cares about its imaging direction 43 extends around.

The camera 10a is so in the X-ray system 34 Integrate that on one near the X-ray source 38 in the X-ray cone 42 lying mirror 46 is directed. The direction of view 11a the camera 10a after the deflection by the mirror 46 coincides with the imaging direction 43 together. The arrangement of the camera 10a or the mirror 46 takes place in such a way that field of vision 15a with the x-ray cone 42 coincides or at least contains this. This ensures that all in X-ray 44 pictured fluoroscopic information of the patient 2 also in the form of the illuminated patient surface of the camera 10a is shown.

In other words, it succeeds with the help of the X-ray image 44 the from the camera 10a in the camera picture 20a recorded body surface or region of the patient 2 in addition to render radiopaque. In particular, both images can be displayed congruently or be blended into each other depending on the weighting.

5a shows a camera picture 20a that with the x-ray system 34 according to 4 has been recorded. That to the camera picture 20a Simultaneously recorded X-ray image 44 is right in the picture 20 appears. In the area of the X-ray image 44 are therefore also bone structures 48 inside the patient 2 visible, noticeable. Besides, also the tip is 7 of the instrument 6 now completely, namely due to the fluoroscopy and the image content of the X-ray image 44 visible, noticeable. 5b shows another combination of camera image 20 and X-ray image 44 which was obtained in such a way that in 4 the x-ray machine 36 or the C-arm in the direction of the arrow 50 was pivoted by 90 °. Again, the patient is back 2 from the side as image content of the camera image 20a as well as bone structures 48 in the patient 2 as image content of the X-ray image 44 visible in superimposed representation.

Again, each is again a placemark 28 for the position of the tip 7 of the instrument 6 Locally correct in the X-ray image 44 and the camera image 20 appears.

LIST OF REFERENCE NUMBERS

2

patient

4

patient table

6

instrument

7

top

8th

navigation system

10a, b

camera

11a, b

line of sight

12a, b

navigation markers

13

operation area

14a-d

coordinate system

15a, b

field of view

16

evaluation

18

image sensor

20a, b

camera image

22a, b

marker element

23

location

24

Just

26

level

28

placemark

30

relative arrangement

34

X-ray system

36

X-ray machine

38

X-ray

40

X-ray detector

42

X-cone

43

imaging direction

44

X-ray photograph

46

mirror

48

bone structure

50

arrow

X, y

distance

Z _{I, R}

relative position

Claims (8)

Navigation system (8), with at least one camera (10a, b), and with at least one navigation marker (12a, b) with at least four identifiable by the camera (10a, b) in at least one camera image (20a, b) marker elements (22a , b), wherein three of the marker elements (22a, b) define a plane (26) and the fourth marker element (22a, b) lies outside the plane (26) with a position (23) of the images of the marker elements (22a , b) in the camera image (20a, b) the relative position (z _{I, R} ) of the navigation marker (12a, b) to the camera (10a, b) determining evaluation unit (16), wherein the camera (10a, b) an endoscopic or laparoscopic camera is. Navigation system (8) to Claim 1 in which the marker elements (22a, b) within the navigation marker (12a, b) differ in terms of their color and / or geometry. Navigation system (8) according to one of the preceding claims, with at least two navigation markers (12a, b), which differ in terms of color and / or geometry and / or geometric relative arrangement (30) of their marker elements (22a, b). Navigation system (8) according to one of the preceding claims, in which the marker elements (22a, b) are applied as a marking on a surface of the navigation marker (12a, b). Navigation system (8) according to one of the preceding claims, with at least one second camera (10a, b). X-ray system (34) having an X-ray device (36) and at least one X-ray image (44) according to one of the preceding claims, in which the camera (10a, b) is integrated in the X-ray device (34) such that its Viewing direction (11a, b) coincides with the imaging direction (43) of the x-ray device (36). X-ray system (34) after Claim 6 in which the X-ray machine (36) is a C-arm X-ray machine. X-ray system (34) after Claim 6 or 7 , with a location mark (28) which correlates with the navigation marker (12a, b) with the aid of the relative position (z _{I, R} ) in place in the x-ray image (44).

Images