DE102017110816A1 - An optical observation apparatus and method for efficiently performing an automatic focusing algorithm - Google Patents

Abstract

A method is provided for efficiently performing an automatic focusing algorithm. The method comprises detecting (101) a position of an optical focusing device having an automatic focusing unit relative to a position of an object at a first point in time. It further comprises, based on the position of the optical observation device relative to the position of the object, detecting (102) a start distance between the optical observation device and an observation area on the object and performing an automatic focusing algorithm with the start distance as the initial focus distance (103).

Description

The present invention relates to a method for efficiently performing an automatic focusing algorithm. In addition, the invention relates to an optical observation device.

Optical observation devices are, for example, microscopes or microscope systems, and their optical systems have, for example, tube lenses for observing an observation area of an object by the user of the optical observation device and / or record the observation beam paths of at least the observation area of interest after passing through the associated optical system via image sensors which are therefrom Image signals, for example, in digital form, generate these then with a visualization component, ie For example, to display on one or more displays the observer and possibly also save or supply to another image processing. The visualization component can be an integral part of the optical observation device or microscope system, but also be connected or connectable with the image acquisition component containing the optical system without necessarily being arranged locally, provided, for example, a wired or wireless transmission of the image signals to the visualization component is made possible. In this way, the optical observation device or its image recording component, for example, also be movably attached to a tripod or programmable robotic arm and the visualization component for the user are still optimally convenient arranged visible.

Optical observation devices or their optical systems have a limited depth of focus range. For example, with the use of surgical microscopes, it is important that the observed object or field of interest on the object, for example, the site, i. The operation area, which may be on the patient during an operation, to keep as long as possible in the depth of field, as outside of this range, the observation area for the user appears blurred. Therefore, as focal plane of the optical observation device or its optical system should always be selected that in which the object or the observation area is located. Since the position of the optical observer or the observed object or, for example, in a surgical procedure can change the viewing area itself and thus the working distance, i. the focus distance, a rapid resetting of the focus distance of the optical observation device may be required, which is preferably done automatically.

For example, surgical microscopes can be equipped with varioscope objectives in which at least two lenses displaceable relative to each other along the optical axis are present, whereby the focus distance of the object and thus the working distance of the surgical microscope can be varied by displacing the two lenses relative to each other, without the position of the surgical microscope itself to change so that the viewing position for the user of the surgical microscope when setting the working distance remains unchanged. Optical observation apparatuses may have autofocus functionality in which an automatic focusing algorithm is executed by which the focus distance is optimized based on the evaluation of sensor data, for example image data, by means of an automatic focusing unit having a control unit and a motor.

Image-based methods for autofocus determination generate information about the best focus distance from available image data from the observation area. For example, in the EP2373043 have shown that for this purpose a stereoscopic approach can be used in which the best focus distance is calculated by evaluating the offset between object features visible in the first and in the second stereo image.

However, image-based methods for autofocus determination require some entropy in the image data to be analyzed. However, this may not be the case if the subject is out of the depth-of-field of the imaging system. In non-iterative methods (e.g., stereoscopy), the focus distance calculation can not be done if there is too little texture in the two images to detect corresponding pixels in the left and right images. This may for example be the case with high zoom levels or values of the optical observation device.

Other image-based automatic focusing methods, for example, provide for determining a focus based on the image content (e.g., edges, contrast), which is then optimized in an iterative algorithm where the focal distance is varied.

However, this can be a time-consuming process, especially if the possible value range of focus values has to be changed until the observation area is in the depth of field of the image acquisition system, which can hinder an efficient use of the optical observation device. For example, with changes in the position, ie the position and / or orientation, of a surgical microscope in surgical use, the focus area strong vary, although the user, ie the surgeon, relies on a continuously as possible sharp view of the observation area, if possible without manually make settings themselves. In order to ensure a seamless working of the user as possible, a used autofocus method, ie a used automatic focusing algorithm, should be properly initialized, so that the focusing algorithm can lead to a result more quickly.

It is therefore an object of the present invention to improve the use of automatic focusing algorithms for optical observation devices to the effect that as quickly as possible automatically optimized focus distance is set.

This object is achieved according to the invention with a method for efficiently carrying out an automatic focusing algorithm according to independent claim 1 and an optical observation device according to independent claim 12. Preferred embodiments and further developments of the invention will become apparent from the dependent claims.

The method according to the invention for efficiently carrying out an automatic focusing algorithm comprises firstly detecting a position of an optical observation device having an automatic focusing unit relative to a position of an object at a first point in time. Based on the position of the optical observation device relative to the position of the object, a starting distance between the optical observation device and an observation area on the object is detected and an automatic focusing algorithm is carried out with the starting distance determined as the initial focus distance.

In this way, it is ensured that the autofocus method, i. the automatic focusing algorithm starts at an expected reasonable focus distance and therefore an optimized result can be quickly found.

The observation area should lie in the focal plane and may, depending on the application, comprise the entire object or a subregion thereof. For example, if a surgical microscope is used in a surgical procedure, the object may be exposed to the patient and the viewing area to the site, i. the field of surgery.

The detection of the start distance may in particular comprise calculating by evaluating the relative position information, whereby a measurement with an otherwise additionally to be provided device can be avoided.

In one embodiment, detecting the location, i. the position and / or orientation of the optical focusing device having an automatic focusing unit relative to the position of the object detecting and relating the absolute positions of the optical observation device and the object, i. detecting the positions of the viewing optical device and the object (directly or indirectly) relative to a common fixed reference or coordinate system. This offers, for example, the advantage that even when simultaneous absolute changes in position of both the optical observation device and the object can be registered separately from each other, even if these possibly at least partially compensate each other relative to each other, so that a new autofocusing safety anyway be initiated can, in order to ensure the highest possible precision in each case.

The position information of the optical observation device can be detected, for example, by sensors included in the device or, in particular, by evaluation of externally acquired sensor data of a suitable position detection system, for example an external camera system or optical tracking system. The position of the object can likewise be detected by evaluating sensor data or be previously known by, for example, structural specifications as to how the object is to be arranged.

The observation area is part of the object, therefore detecting the position of the object also involves detecting the position of the observation area. The observation area lies on the object and refers to the currently visible surface. This implies, for example, that the surgical site may also be considered intra-patient during a surgical procedure.

In a further embodiment, the detection of the position of the optical observation device relative to the position of the object comprises detecting the position of the object with a sensor arranged on the optical observation device, ie the relative position to each other is detected directly by evaluating sensor data directly on the sensor optical observation device arranged sensor, for example by optical tracking of the object or at least a reference point on the object in signals such as an environment camera or a topographic sensor of the optical observation device. This offers, for example, the advantage that possibly available sensor data can be evaluated. In addition, a sensor arranged on the optical observation device is in a good position suitable position, in order to be able to detect even smaller changes in distance, which arise, for example, by changing the observation area, for example, by sections of a surgeon in the patient's situs.

In yet another embodiment, detecting the position of the optical focusing device having an automatic focusing unit relative to the position of the object comprises detecting the position of the optical observation device with a sensor disposed on the object, i. Sensor data of a sensor placed directly on the object, e.g. by optical tracking of the optical observation device or at least one reference point on the optical observation device in camera data of a camera attached to the object. The attachment of the sensor to the object offers, for example, the advantage that an attachment of a sensor to the optical observation device can be avoided if it does not already have a suitable sensor. In addition, the shape of the object, e.g. the anatomy of the patient, to be considered individually in the arrangement of the sensor.

In an embodiment, the method further comprises detecting navigation data related to the object. These contain the navigation data related to the observation area or these can be generated from the object-related navigation data. The acquisition or calculation of the start distance then takes place as a function of navigation data related to the observation area of the object. For example, navigation data may be topographical data, but may also include, for example, volume data and non-visible portions of the object, e.g. consider in a patient the anatomy and nature of areas that do not enter the field of view of the optical scope until the surgery. For example, in a skull operation volume data of the skull can serve as navigation data or volume data on areas that the surgeon exposes only through cuts during the operation. For this purpose data measured directly on the patient can be used, but also standardized data sets from a database, which can be used for example. typical forms, for example of the skull, describe e.g. in the form of an individualized or standardized patient atlas.

In addition to temporally previously recorded navigation data and data can be used, which are detected only during the operation of the optical observation device. For example, intraoperative data can be used during an operation in addition to pre-operative data. With knowledge of the current relative position between the optical observation device and the object or patient, an internal or external control unit or a navigation system based on the pre- and / or intraoperative data can calculate the expected focus distance to the situs and the starting distance for the automatic Provide focusing algorithm. Even if the relative position changes, a new initial focus distance can be determined quickly, if necessary.

In one embodiment, it is provided to detect a change in the position of the optical observation device relative to the position of the object at least a second time and to detect an updated distance between the optical observation device and the observation area as the updated initial focus distance based on the change. to calculate.

This offers the advantage that an updated focus distance value is available by checking or tracking the relative position of the optical observation device and object to one another at least one, preferably a plurality of points in time after the original determination of the initial focus distance, with which a renewed automatic focusing is performed can be. In an exemplary embodiment, it is contemplated to re-execute the automatic focus algorithm with the updated initial focus distance immediately. Although the updated initial focus distance is determined in another example embodiment, the re-autofocusing is triggered only by a user command signal, such as a button press or voice prompt, to allow the user to control exactly when the short autofocus is in the user's workflow at least as disturbing.

In a further exemplary embodiment, if there is navigation data related to the object, the detection of the updated distance takes place as a function of the navigation data related to the observation area of the object. In this case, the navigation data related to the object include, at least as a subset, the navigation data related to the observation area of the object.

If there is a change in the relative position between the optical observation device and the object, this can, depending on the application, sometimes result in a significant change in the focal plane. If the navigation data are available, however, based on this, a strongly deviating updated distance as the initial focus distance for a new one can very quickly arise Execution of the automatic focusing algorithm.

In a further embodiment, detecting the change in the position of the optical observation device relative to the position of the object comprises detecting a change in the position of the optical observation device at least at the second time relative to the position of the optical observation device at the first time. Thus, the absolute change in position of the optical observation device is checked from the first at least to the second time.

In particular, if a change in position of the object is only slight or very unlikely, the monitoring of the relative position between the optical observation device and the object can be reduced to monitoring the change in position of the optical observation device. Since, for example, some surgical microscopes provide position information anyway, the calculation effort for the calculation of the initial focal distance is considerably reduced.

The assumption of the constant object position is permissible for many objects, of which only the surface is considered without making changes to the object. If the optical observation device is, for example, a surgical microscope and the object is a patient, motionlessness, for example, under anesthesia, depending on the procedure performed, is also approximately acceptable.

Alternatively or additionally, in one embodiment, detecting the change in the position of the optical observation device relative to the position of the object comprises detecting a change in the position of the object at least at the second time relative to the position of the object at the first time. In particular, if the absolute position of the optical observation device is fixed, for example, if it is firmly locked in a position or no possibility of changing the position, it may be sufficient to monitor the changes in the object position, so that also reduces the calculation effort to the to determine the initial focus value (new).

In a further embodiment, it is first checked whether the updated distance differs by more than a tolerance value from the starting distance, and if this is the case, the automatic focusing algorithm is executed with the updated initial focus distance and the updated distance as the new starting distance. Distance set. The automatic focusing algorithm is not executed immediately with every change of distance, but only when the starting distance is exceeded or fallen below by the tolerance value. Minor deviations caused by slight defocusing, for example due to carelessness of the user, can thus be ignored in favor of an undisturbed workflow if they are within the tolerance range.

In one embodiment, at least the detection of the change takes place at a plurality of different times or continuously. This offers the advantage of being able to track or track the change in the relative position continuously or, for example, at regular time intervals so as to be able to recognize as soon as possible any situation in which re-autofocusing would be advantageous.

In another embodiment, the method further comprises decreasing an original zoom level of the optical viewing device prior to performing the automatic focusing algorithm and increasing the reduced zoom level to the original value after performing the automatic focusing algorithm.

In order to obtain an extended field-of-view or field of view, in particular in the case of otherwise existing high zoom values of the optical observation device, a low zoom value is automatically set in the short term in order to carry out the automatic focusing algorithm there. After the determined focus distance, the original zoom value is set again. Increasing the field-of-view (with an unchanged focus distance) has the advantage that more information is available for the focusing algorithm for determining the focal distance and the determination can therefore be more robust and also faster.

In an exemplary embodiment, decreasing the original zoom value and increasing to the original zoom value occur only when the original zoom level is above a threshold. This has the advantage that this field of view enlargement is performed only for large zoom values, in which the probability is high that otherwise due to the high magnification, no or only a few structures are present in the observation area, which can be evaluated for automatic focusing.

In another exemplary embodiment, if the optical scope has more than one viewing channel, reducing the original zoom level and increasing to the original zoom level on at least one of the viewing channels.

For example, if a separate video channel is available, the fast zooming described above can only be performed on the video channel, so that the user is less disturbed. In a digital system with multiple channels, the process can be performed either on the whole system or only on one of the channels, eg on the SW channel. In one embodiment, it may further be provided to apply the focus distance determined on one channel to other channels.

The subject matter of an independent claim relates to an optical observation device which comprises at least one optical system with an adjustable focus distance, an automatic focusing unit, a position detection unit, at least one interface for receiving at least one object position information and a control unit with a memory, wherein the optical observation device is set up to carry out a method according to the invention. In this way, the advantages and special features of the method according to the invention for the efficient execution of an automatic focusing algorithm are also implemented in the context of an optical observation device. The optical system may in this case include, for example, a zoom lens. The automatic focusing unit has means to perform the respective Autofokussierung depending on the method. The object position information can be received as information measured by another device via the interface, or the interface is the to a separate sensor or measurement unit, so that the observation device actually generates all the data itself. The memory may include a program for performing the Autofokussieralgorithmus, can cache the initial focus distance, as well as possibly the original zoom value, possibly also navigation data. Depending on the embodiment, navigation data can also be received via the at least one interface or a connection can be made to a detection unit for the navigation data or a navigation system.

In a preferred embodiment, the optical observation device is a (for example digital) surgical microscope or surgical microscope or forms part of a surgical microscope.

• 1 eine schematische Darstellung eines Beispiels für den grundsätzlichen Aufbau eines Operationsmikroskops mit Unendlichstrahlengang;
• 2 eine schematische Darstellung eines Varioskopobjektivs;
• 3 eine schematische Darstellung eines Beispiels für den grundsätzlichen Aufbau eines digitalen Operationsmikroskops;
• 4 eine schematische Darstellung einer beispielhaften Ausführungsform eines erfindungsgemäßen Verfahrens zum effizienten Ausführen eines automatischen Fokussieralgorithmus;
• 5 eine schematische Darstellung einer weiteren beispielhaften Ausführungsform eines erfindungsgemäßen Verfahrens zum effizienten Ausführen eines automatischen Fokussieralgorithmus;
• 6 eine schematische Darstellung einer beispielhaften Ausführungsform eines erfindungsgemäßen optischen Beobachtungsgeräts;
• 7 eine schematische Darstellung eines ersten Beispiels einer Möglichkeit, einen Fokusabstand basierend auf einer Lage eines eine automatische Fokussiereinheit aufweisenden optischen Beobachtungsgeräts relativ zu einer Lage eines Objekts zu bestimmen;
• 8 eine schematische Darstellung eines zweiten Beispiels einer Möglichkeit, einen Fokusabstand basierend auf einer Lage eines eine automatische Fokussiereinheit aufweisenden optischen Beobachtungsgeräts relativ zu einer Lage eines Objekts zu bestimmen; und
• 9 eine schematische Darstellung eines dritten Beispiels einer Möglichkeit, einen Fokusabstand basierend auf einer Lage eines eine automatische Fokussiereinheit aufweisenden optischen Beobachtungsgeräts relativ zu einer Lage eines Objekts zu bestimmen.

The invention will be explained in more detail below in conjunction with the following description of embodiments with reference to the accompanying drawings. Show it:

• 1 a schematic representation of an example of the basic structure of a surgical microscope with infinite beam path;
• 2 a schematic representation of a Varioskopobjektivs;
• 3 a schematic representation of an example of the basic structure of a digital surgical microscope;
• 4 a schematic representation of an exemplary embodiment of a method according to the invention for efficiently carrying out an automatic focusing algorithm;
• 5 a schematic representation of another exemplary embodiment of a method according to the invention for efficiently carrying out an automatic focusing algorithm;
• 6 a schematic representation of an exemplary embodiment of an optical observation device according to the invention;
• 7 a schematic representation of a first example of a way to determine a focal distance based on a position of an automatic focusing unit having optical observation device relative to a position of an object;
• 8th a schematic representation of a second example of a way to determine a focal distance based on a position of an automatic focusing unit having optical observation device relative to a position of an object; and
• 9 a schematic representation of a third example of a way to determine a focal distance based on a position of an automatic focusing unit having optical observation device relative to a position of an object.

In the figures, identical or similar elements are provided with identical reference numerals, as appropriate.

It should be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. It should be understood that the features of the various exemplary embodiments described may be combined with each other unless specifically stated otherwise. The description is therefore not to be considered in a limiting sense, and the scope of the present invention is defined by the appended claims.

Hereinafter, with reference to 1 and 2 a possible construction of a surgical microscope 2 illustrated, which serves as an example of an optical observation device, for example, according to 6 can be extended to perform the inventive method for efficiently performing an automatic focusing algorithm.

This in 1 shown surgical microscope 2 includes an object field 3 facing lens 5 , The object field 3 is in the focal plane of the lens 5 arranged so that it is from the lens 5 mapped to infinity. In other words, one from the object field 3 outgoing divergent beam 7 becomes in its passage through the lens 5 in a parallel beam 9 transformed. Such a beam path is also called infinite beam path.

In 1 is the lens 5 for the sake of simplicity only shown schematically as Achromatlinse. To the working distance of the surgical microscope 2 ie the distance of the object-side focal plane from the underside of the surgical microscope 2 to be able to vary without the surgical microscope 2 Having to go by yourself can be done in a surgical microscope 2 Instead of a simple achromatic lens, an objective lens system comprising a plurality of lenses is used, with which the operating distance of the surgical microscope 2 varies by varying the focal distance. Such an object, with which the focus distance can be varied, is sometimes called a varifocal lens.

An example of a varifocal lens or varioscope objective is shown schematically in FIG 2 shown. The Vario lens 50 includes a positive member 51 , ie an optical element with positive refractive power, which in 2 is shown schematically as a convex lens. In addition, the Vario lens includes 50 a negative link 52 , so an optical element with negative refractive power, the in 2 is shown schematically as a concave lens. The negative link 52 is located between the positive member 51 and the object field 3 , In the illustrated zoom lens 50 is the negative link 52 fixed, whereas the positive member 51 as by the double arrow 53 indicated slidably disposed along the optical axis OA. When the positive member 51 in the in 2 dashed position is shifted, the focus distance is extended, so that the working distance of the surgical microscope 2 from the object field 3 changes.

Although in the in 2 illustrated Vario lens 50 the positive member 51 is designed to be displaceable, there is also in principle the possibility of the negative member 52 instead of the positive member 51 to arrange movable along the optical axis OA. The negative link 52 however, often forms the terminating lens of the varifocal lens 50 , A fixed negative link 52 therefore offers the advantage of having the interior of the surgical microscope 2 can be sealed more easily against external influences. It should also be noted that although the positive member 51 and the negative link 52 in 2 are shown as single lenses, each of these members can be realized instead of in the form of a single lens in the form of a lens group or a putty member, for example. To the zoom lens 50 achromatic or apochromatic form.

Observer side of the lens 5 is a magnification changer 11 arranged, which can be formed either as in the illustrated embodiment as a zoom system for stepless change of the magnification factor or as a so-called Galilei changer for stepwise change of the magnification factor. In a zoom system, which is constructed, for example, from a combination of lenses with three lenses, the two object-side lenses can be moved to vary the magnification factor. In fact, however, the zoom system can also have more than three lenses, for example four or more lenses, the outer lenses then being able to be fixed. In a Galilean changer, on the other hand, there are several fixed lens combinations that represent different magnification factors and that can be alternately introduced into the beam path. Both a zoom system and a Galilean changer convert an object-side parallel beam into an observer-side parallel beam with a different beam diameter. The magnification changer 11 In the present embodiment, it is already part of the binocular beam path of the surgical microscope 1, ie it has its own lens combination for each stereoscopic partial beam path 9A . 9B of the surgical microscope 1. Setting a magnification factor using the magnification changer 11 takes place in the present embodiment, a motor-driven actuator, which together with the magnification changer 11 Part of a magnification change unit for setting the magnification factor.

To the magnification changer 11 closes observer side, an interface arrangement 13A . 13B on, via the external devices to the surgical microscope 1 can be connected and the beam splitter prisms in the present embodiment 15A . 15B includes. In principle, however, other types of beam splitters may also be used, for example partially transmissive mirrors. The interfaces 13A . 13B serve in the present embodiment for decoupling a beam from the beam path of the surgical microscope 2 (Beam splitter prism 15B ) or for coupling a beam in the beam path of the surgical microscope 2 (Beam splitter prism 15A ). However, both interfaces can be used 13A . 13B for coupling or both interfaces 13A , 13B for coupling out bundles of rays.

The beam splitter prism 15A in the partial beam path 9A used in the present embodiment, with the help of a display 37 For example, a digital mirror device (DMD) or an LCD display, and an associated optics 39 via the beam splitter prism 15A Information or data for a viewer in the sub-beam path 9A einzuspiegeln the surgical microscope 1. In the other partial beam path 9B is at the interface 13B a camera adapter 19 with a camera attached to it 21 arranged with an electronic image sensor 23 , For example, with a CCD sensor or a CMOS sensor equipped. By means of the camera 21 can be an electronic and especially a digital image of the tissue area 3 be recorded. In particular, a hyperspectral sensor in which not only three spectral channels (for example red, green and blue) are present but also a multiplicity of spectral channels can be used as the image sensor.

At the interface 13, a binocular tube closes observer side 27 at. This has two tube lenses 29A . 29B on which the respective parallel beam 9A . 9B focus on an intermediate image plane 31, so the observation object 3 to the respective intermediate image plane 31A , 31B. The in the intermediate picture planes 31A . 31B intermediate images are finally from eyepiece lenses 35A . 35B again shown to infinity, so that a viewer can view the intermediate image with a relaxed eye. In addition, in the binocular tube by means of a mirror system or prisms 33A . 33B an increase in the distance between the two partial beams 9A , 9B to adjust it to the eye relief of the observer. With the mirror system or the prisms 33A . 33B In addition, a picture erection takes place.

The surgical microscope 2 is also equipped with a lighting device with which the object field 3 can be illuminated with broadband illumination light. For this purpose, the lighting device in the present embodiment, a white light source 41 , such as a halogen bulb or a gas discharge lamp on. That from the white light source 41 Outgoing light is transmitted through a deflecting mirror 43 or a deflection prism in the direction of the object field 3 steered to illuminate this. In the lighting device is also an illumination optics 45 present, for a uniform illumination of the entire observed object field 3 provides.

It should be noted that the in 1 Illuminating beam path shown is highly schematic and does not necessarily reflect the actual course of the illumination beam path. In principle, the illumination beam path can be embodied as so-called oblique illumination, which corresponds to the schematic representation in FIG 1 comes closest. In such an oblique illumination of the beam path is at a relatively large angle (6 ° or more) to the optical axis of the lens 5 and can, as in 1 shown completely outside the lens. Alternatively, however, it is also possible, the illumination beam path of the oblique illumination through an edge region of the lens 5 pass through. Another possibility for the arrangement of the illumination beam path is the so-called 0 ° illumination, in which the illumination beam path through the lens 5 passes through and between the two partial beam paths 9A . 9B , along the optical axis of the lens 5 towards the object field 3 is coupled into the lens. Finally, it is also possible to carry out the illumination beam path as so-called coaxial illumination, in which a first and a second illumination beam path are present. The partial beam paths are parallel to the optical axes of the observation partial beam paths via one or more beam splitters 9A . 9B coupled into the surgical microscope, so that the illumination is coaxial with the two observation partial beam paths.

3 shows an example of a digital surgical microscope 48 in a schematic representation. In this surgical microscope, the main lens differ 5 , the magnification changer 11 as well as the lighting system 41 . 43 . 45 not of that in 1 illustrated surgical microscope 2 with optical insight. The difference is that the in 3 shown surgical microscope 48 does not include an optical binocular tube. Instead of the tube lenses 29A . 29B out 1 includes the surgical microscope 48 out 3 focusing lenses 49A . 49B with which the binocular observation beam paths 9A . 9B on digital image sensors 61A . 61B be imaged. The digital image sensors 61A , 61B may be formed for example as CCD sensors or as CMOS sensors. The of the image sensors 61A . 61B taken pictures are digital to digital displays 63A . 63B which can be formed, for example, as LED displays, as LCD displays or displays based on organic light emitting diodes (OLEDs). The displays 63A . 63B can, as in this example, eyepiece lenses 65A . 65B be associated with those on the displays 63A , 63B, so that an observer can look at them with relaxed eyes. The displays 63A , 63B and the eyepiece lenses 65A . 65B can be part of a digital binocular tube, but they can also be part of a head-mounted display, for example (head mounted display, HMD), such as data glasses.

Although in 3 as in 1 only an achromatic lens 5 is shown with a fixed focal length, the in 3 shown surgical microscope 48 as in 1 illustrated surgical microscope 2 a varioscope lens instead of the objective lens 5 include. Furthermore, in 3 a transmission of the image sensors 61A . 61B taken pictures to the displays 63A . 63B by means of cables 67A . 67B shown. However, instead of being wired, the images can also be sent wirelessly to the displays 63A , 63B, especially when the displays 63A . 63B Part of a head mounted displays are.

4 shows a schematic representation of an exemplary embodiment of a method according to the invention for efficiently performing an automatic focusing algorithm. It is provided to detect a position of an automatic focusing unit having an optical observation device relative to a position of an object at a first time 101. Based on the thus determined position of the optical observation device relative to the position of the object is detected in a next step 102 a start distance between the optical observation device and an observation area on the object. Then, in an additional step, an automatic focusing algorithm is executed 103 with the starting distance as the initial focus distance.

In the embodiment shown, it is additionally provided to first acquire navigation data relating to the object 104. With these, the acquisition can 102 the start distance then take place as a function of navigation data related to the observation area of the object, which are part of the navigation data related to the object.

In the embodiment shown, the method does not end with executing the suitably initialized automatic focusing algorithm once, but is continued in order to be able to take into account later changes in the relative position between the optical observation device and the object.

In a next step, a change of the position of the optical observation device relative to the position of the object is detected 105 at least a second time point. This determination of the relative change in position comprises detection in the embodiment shown 106 a change in the position of the optical observation device at least at the second time point relative to the position of the optical observation device at the first time and a detection 107 a change in the position of the object at least at the second time relative to the position of the object at the first time. In the embodiment shown, it is further provided to detect 105 the change of the position of the optical observation device relative to the position of the object to carry out continuous time. Based on the change is then detected 108 an updated distance between the optical observation device and the observation area as the updated initial focus distance.

An actual re-execution of the automatic focusing algorithm should only be done if the change is not too small. Therefore, in a next step, it is checked whether the updated distance differs by more than a tolerance value from the starting distance 109. If so, the automatic focusing algorithm is executed again with the updated initial focus distance 103. In addition, the updated distance becomes new start distance is set 110, so that the next tolerance range violation will be based on the range around the new start distance. If the change is still in the tolerance range, no autofocusing will take place, but the procedure goes to step 105 continued and the relative change in position further monitored. The process ends when the optical observer or its autofocus functionality is deactivated.

5 shows a schematic representation of another exemplary embodiment of a method according to the invention for efficiently performing an automatic focusing algorithm. For the sake of clarity, the method here is limited to a one-time initialized execution of the automatic focusing algorithm. Other embodiments may also here as in the 4 shown example also provide detection of later changes in position.

After the start, first in a first step 201 the current, ie the original, zoom value of the optical observation device is detected. In a next step 202 it is then checked if the original zoom value is above a threshold. If this is true, then first a decrease 203 the original zoom value of the optical observation device performed. Thereafter, when the zoom level is decreased, the detection is made 101 the position of the optical focusing device having an automatic focusing unit relative to the position of the object at the first time, wherein, based on the position of the optical observation device relative to the position of the object, the starting distance between the optical observation device and the observation area on the object is detected 102 and finally the automatic focusing algorithm After that, if checking whether the original zoom value is above the threshold 202 has been found to be the case 103, that is, if the zoom value was previously decreased and zoomed out, then the reduced zoom value is increased 204 back to the original zoom level and the method shown ends. Returns the check for the original zoom value 202 that the threshold is not exceeded, become the steps 101 . 102 and 103 executed without changing the zoom value.

6 shows a schematic representation of an exemplary embodiment of an optical observation device according to the invention.

In the illustrated embodiment, the optical viewing device 300, which may be, for example, a surgical microscope, comprises an optical system 301 with an adjustable focus distance and an automatic focusing unit 302 with which the focus distance can be adjusted automatically. In addition, the optical observation device has a position detection unit 303 on, with the position, ie the position and / or orientation, the optical observation device is detected. In addition, at least one interface 304 is provided for receiving at least one object position information. Both the automatic focusing unit 302 , as well as the location detection unit 303 and the interface 304 are directly or indirectly communicative with a control unit 305 with an associated memory 306 which evaluates and appropriately drives the information provided by the units to perform a method of efficiently performing an automatic focusing algorithm in accordance with the invention. For example, the controller 305 may be a processor, microcontroller, or other programmable device that has instructions in memory 306 stored program. The memory 306 In addition, it can be used for temporarily storing determined parameter values, for example the initial focus distance, the current position information or, depending on the embodiment, also navigation data.

7 FIG. 12 shows a schematic representation of a first example of a possibility of determining a focal distance based on a position of an optical observation device having an automatic focusing unit relative to a position of an object. In the optical observation device 400 it may be, for example, a digital surgical microscope or other recording device with autofocus function, in which the recorded observation area can be displayed either directly on the observation device or eg on (not shown) separate displays or a head mounted display. The optical observation device is movable on a stand in the embodiment shown 401 or programmable movable robot arm and may be used by the user, for example, a surgeon, with respect to an observed object 402 For example, the patient or the situs, be moved in space. In order to determine the focus distance 403, is via an external position sensing device 404 the position, ie the position and / or orientation of the optical observation device 400 relative to the location of the object 402 by detecting and relating the absolute positions of the viewing optical device 400 and the object 402 detected, based on the position of the position detection device 404 and thus to a common fixed reference or coordinate system.

In the embodiment shown, it is provided as unique reference points for the detection of the position of the optical observation device 400 and the object 402 first and second reference points 405 . 406 to use. It should be noted that each reference point shown 405 . 406 can stand for one or more reference points to be used. To mark the reference points, for example, stickable 2D markers can be used, especially if the position detection device used 404 performs an optical tracking of the reference points. Based on the position detection by the position sensing device 404 not on visible light, other suitable markers may be used accordingly, for example infrared markers in an infrared-based tracking system.

8th FIG. 12 shows a schematic representation of a second example of a possibility of determining a focal distance based on a position of an optical observation device having an automatic focusing unit relative to a position of an object. For the sake of clarity, like reference numerals designate like or similar elements as in FIG 7 and only differing elements will be explained. Unlike in 7 shown here is not an external position sensing device, the location of the optical observation device 400 relative to the location of the object 402 detected. Instead, the location of the object 402 with a directly on the optical observation device 400 arranged sensor 407 detected. In the embodiment shown, the relative position to each other is detected directly by evaluating the sensor data. At the sensor 407 it may, for example, be an environment camera or a topographical sensor and the position or position of the second reference point 406 is tracked by optical tracking in the sensor data. The first reference point 405 is related to optical system of the optical observation device with automatic focusing unit, allowing changes in focus distance 403 based on the change in position of the second reference point 406 relative to the first reference point 405 can be determined.

9 FIG. 12 shows a schematic representation of a third example of a possibility of determining a focal distance based on a position of an optical focusing device having an automatic focusing unit relative to a position of an object. For the sake of clarity, like reference numerals designate like or similar elements as in FIG 7 and 8th and only differing elements will be explained. Unlike in 8th shown, the location of the object 402 not detected with a sensor arranged on the optical observation device. Instead, here is the location of the optical viewing device 400 with one on the object 402 arranged sensor 408 , For example, a camera detected, for example by optical tracking of the optical observation device 400 or at least the first reference point 405 on the optical observation device 400 in camera data on the object 402 attached camera while the location of the second reference point 406 relative to the position of the sensor 408 stays the same, allowing changes in focus distance 403 based on the change in position of the first reference point 405 relative to the second reference point 406 can be determined.

The present invention has been described in detail by way of embodiments for explanatory purposes. Those skilled in the art will recognize that details described with respect to one embodiment may also be used in other embodiments. The invention is therefore not intended to be limited to individual embodiments, but only by the appended claims.

LIST OF REFERENCE NUMBERS

2

surgical microscope

3

surgical field

5

lens

7

Divergent beam

9

ray beam

9A, 9B

stereoscopic partial beam path

11

magnification changer

13A, 13B

Interface arrangement

15A, 15B

Beam splitter prism

19

camera adapter

21

camera

23

image sensor

27

binocular

29A, 29B

tube objective

31A, 31B

Intermediate image plane

33A, 33B

prism

35A, 35B

eyepiece

37

display

39

optics

41

White light source

43

deflecting

45

illumination optics

48

digital surgical microscope

49A, 49B

focusing lens

50

Varifocal lens

51

positive element

52

negative element

53

displacement

61A, 61B

digital image sensor

63A, 63B

digital display

65A, 65B

eyepiece

67A, 67B

electric wire

101

Detecting the relative position of the optical observation device

102

Detecting a start distance

103

Perform an automatic focusing algorithm

104

Capture navigation data

105

Detecting a relative change in position

106

Detecting the change in position of the optical observation device

107

Capture the change in position of the object

108

Detecting an updated distance

109

Check a tolerance range violation

110

Set the updated distance as the new start distance

201

Capture the original zoom value

202

Check if zoom value exceeds threshold

203

Decrease the original zoom level

204

Increase the reduced zoom value

300

Optical observation device

301

Optical system

302

Automatic focusing unit

303

Position detection unit

304

interface

305

control unit

306

Storage

400

optical observation device

401

tripod

402

object

403

focus distance

404

external position detection device

405

first reference point

406

second reference point

407

sensor

408

sensor

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2373043 [0005]

Claims (16)

A method of efficiently performing an automatic focusing algorithm, comprising Detecting (101) a position of an optical focusing device having an automatic focusing unit relative to a position of an object at a first time; Based on the position of the optical observation device relative to the position of the object, detecting (102) a start distance between the observation optical device and an observation area on the object; and Execute (103) an automatic focusing algorithm with the starting distance as the initial focus distance. Method according to Claim 1 wherein the detecting (101) comprises the position of the automatic focusing unit having an optical observation device relative to the position of the object to determine the positions of the optical observation device and the object based on a common fixed reference system. Method according to Claim 1 wherein the detecting (101) comprises the position of the automatic focusing unit having an optical observation device relative to the position of the object to detect the position of the object with a sensor arranged on the optical observation device. Method according to Claim 1 wherein detecting (101) the location of the optical focusing device having an automatic focusing unit relative to the position of the object comprises detecting the position of the optical observation device with a sensor disposed on the object. The method of any one of the preceding claims, further comprising detecting (104) navigation data related to the object; wherein the detection of (102) the starting distance in dependence on the observation area of the object related navigation data takes place. A method according to any one of the preceding claims, comprising at least a second time, detecting (105) a change in the position of the optical observation device relative to the position of the object and based on the change, detecting (108) an updated distance between the optical observation device and the Observation area as updated initial focus distance. Method according to Claim 6 wherein, when there is navigation data related to the object, detecting (108) the updated distance in accordance with the navigation data related to the observation area of the object. Method according to Claim 6 or Claim 7 wherein detecting (105) the change of the position of the optical observation device relative to the position of the object comprises detecting (106) a change in the position of the observation optical device at least at the second time relative to the position of the observation optical device at the first time. Method according to one of Claims 6 to 8th wherein detecting the change in position of the optical observation device relative to the location of the object comprises detecting (107) a change in the location of the object at least at the second time relative to the location of the object at the first time. Method according to one of Claims 6 to 9 further comprising, when the updated distance differs by more than a tolerance value from the starting distance (109), executing (103) the automatic focusing algorithm with the updated initial focus distance, and setting (110) the updated distance as the new starting distance. Method according to one of Claims 6 to 10 wherein at least the detection (105) of the change of the position of the optical observation device relative to the position of the object takes place at a plurality of different times or continuously. The method of any one of the preceding claims, further comprising decreasing (203) an original zoom level of the viewing optical device prior to performing the automatic focusing algorithm and enlarging (204) the reduced zoom level to the original value after performing the automatic focusing algorithm. Method according to Claim 12 wherein decreasing the original zoom level and zooming in to the original zoom level occurs only when the original zoom level is above a threshold (202). Method according to Claim 12 or Claim 13 wherein, if the optical observation device has more than one observation channel, reducing the original zoom value and enlarging to the original zoom value occurs on at least one of the observation channels. An optical observation device (300) comprising an optical system (301) having an adjustable focus distance; an automatic focusing unit (302); a position detection unit (303); at least one interface (304) for receiving at least one object location information; a control unit (305) having a memory (306); wherein the optical observation device is adapted to a method according to one of Claims 1 to 11 perform. Optical observation device after Claim 15 wherein the optical observation device (300) is a surgical microscope.

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