DE102008046346A1 - Spatial region i.e. medical treatment room, monitoring method for X-ray device, involves developing three-dimensional environment model from spatial points, where model specifies space volumes occupied by objects within spatial region - Google Patents

Abstract

The method involves three-dimensionally detecting spatial points of a spatial region (R) using detection units i.e. three-dimensional cameras (7-10), which are arranged in the spatial region. A three-dimensional environment model is developed from the three-dimensional spatial points, where the three-dimensional environment model specifies space volumes occupied by multiple objects e.g. ellipses (A, D), C-shaped arch (1), patient table (2), monitors (3), electro-encephalograph instrument (4), X-ray protective shield (5) and positioning device (6), within the spatial region. An independent claim is also included for a device for monitoring a spatial region of a movable medical device.

Description

The The invention relates to a method and a device for monitoring a spatial Area, in particular the environment of a movable medical Device.

In a variety of technical fields of application there is the requirement spatial areas with devices in it to monitor for example, collisions between the devices and other objects in the Room or the operator to avoid.

in the Medical devices are increasingly being used in medical devices which in the implementation of diagnostics or therapy automated or semi-automated Perform movements. In particular, the problem arises that due to the high Dynamics in medical treatment rooms, eg. B. due to movements the treatment staff or the patient, more and more disturbances occur, which collisions of the moving medical device with persons or objects can cause.

Therefore the invention has the object, a method and a To imagine a device that quickly and reliably vulnerable Monitor area.

These The object is achieved by the method according to claim 1 or by the device according to claim 18 solved. Further developments of the invention are in the dependent claims played.

In the method according to the invention is provided with a plurality of actively ranging measuring means the one to be monitored spatial area captured in three dimensions. From the detected spatial area is then computer-aided created a three-dimensional environment model, which by a or more objects specified volume volumes in the spatial area specified. Under active or direct distance measuring detection means are to understand such detection means, which actively a signal send out and receive again, taking out the change the signal by reflection or scattering on objects or from the Runtime of the transmitted and received signal the distance is determined to objects. The signal can be configured arbitrarily, In particular, it may be electromagnetic waves (eg light in the visible or invisible area) or sound waves (in particular ultrasonic waves) act.

The inventive method has the advantage that through the use of several active distance measuring Detecting means, which may be arranged in arrays, for example can, reliable and three-dimensional space points can be determined quickly, so that the occupancy of the space by objects is not with computationally intensive processing steps from uncertain measurement data needs to be determined. In this way will be a creation of a precise three-dimensional environment model guaranteed in a short computing time.

In the method according to the invention are preferably used as active distance measuring detection means one or more actively distance-measuring 3D cameras and / or one or more pivotable laser scanners and / or one or more Ultrasonic sensors used. For example, distance-measuring cameras the company MESA, z. As the model SR 3000, or two-dimensional Laser scanner, z. Example, the model URG 04-LX Hokuyo or the Model LMS 200 from Sick. The three-dimensional Environment detection is performed on two-dimensional laser scanners achieved a pivot drive of the laser scanner, causing the scanning plane the laser scanner is moved in space and thus the space is three-dimensional is measured.

In a preferred embodiment will be at least part of the spatial Area, in particular the entire spatial area, by actively distance-measuring 3D cameras captured, and in addition becomes a subarea of the spatial Area detected by a pivotable laser scanner. To this Way you can Subareas where there is a high need for accurate environment modeling exists, be recorded separately again by a laser scanner, ensuring the accuracy of the environment model in these subareas elevated becomes. Such subregions are in particular areas in which a increased activity is suspected by movement of objects or persons.

The in the process according to the invention Active distance-measuring detection means used can be arbitrary be arranged in the room. In particular, they can be fixed in place in the room. However, there is also the possibility at least part of the detection means at one or more movable devices to arrange in the room. Thereby can especially areas of spatial Surroundings are detected, which in certain positions of the movable equipment not be seen by stationary detection means can, as they pass through the movable device are shadowed.

In a particularly preferred embodiment, the dynamics of the spatial area is detected, which is characterized by a temporally continuous Monitoring is achieved. That is, the spatial area is detected as an image stream of temporally successive images, wherein the term image stream is to be interpreted broadly and may include any type of three-dimensional measurement data, in particular video images or measurement points of a laser scanner.

In a further embodiment the method according to the invention Detects each actively distance-measuring detection means in one respective subsection of the spatial Area with the occupied by one or more objects Raumvo lumina with a detection probability, taking into account the detection probabilities of all detection means room volumes specified as occupied in the three-dimensional environment model. This will be a suitable settlement of the different Measurement data of the detection means taking into account their detection probabilities reached. For example, a room volume can then be occupied be identified if the detection probability for this Room volume at least for a detection means or for several detection means exceeds a predetermined value.

The individual room volumes in the three-dimensional environment model can be arbitrary be configured, preferably they are cuboidal cells specified. In order to save space, may be unoccupied Room volumes in the environment model combined into a room volume become.

In a particularly preferred embodiment the invention, the occupied space volumes in the three-dimensional Environment model with three-dimensional object types from a database compared to the room volumes based on the comparison result Assign objects. In this way, computer-aided Scene description of the environment can be obtained, which for example for monitoring can be used by collisions.

In a particularly preferred embodiment the method according to the invention is monitored in the space area, a movable device, which by the Device occupied Room volumes identified in the three-dimensional environment model become. This identification may be based on the Comparison of the volume volumes described above with object types a database with the database containing the device as an object type. Based on Such identification of a movable device can in a preferred embodiment of Invention a risk of collision between the movable device and others Objects in the environment model. The determined collision risk can be values in a continuous value range or in one assume discrete value range, the values allow a statement, such as high the risk of collision. For example, an increase or decrease in value represents an increase in collision risk. If necessary, it is possible that the collision risk also exists only between the states "existing Risk of collision "and" not existing collision hazard "differ can.

In a particularly preferred embodiment the determined collision risk is designed such that it the bigger, the smaller a distance measure between the device and the one or more other objects in the room. The distance measure can, for example the smallest distance between object resulting from the environment model and device be.

In a particularly preferred embodiment The invention is further used in determining the risk of collision the future Direction of movement of the device and / or one or more objects in space. there there is a risk of collision if assumed a further movement of the device and / or the one or more other objects in a certain period of time Collision occurs. This is especially the speed the movement of the objects or of the device. The future direction of movement can be determined in several ways. In particular, can from the current and / or past movement direction of the equipment and / or the object (s). It exists, however also the possibility the future Direction of movement Information about the movement to be performed of the device and / or one or more objects. It can in particular Information from the control of the device regarding the movement to be performed be read out.

in the Case that with the method according to the invention a risk of collision is determined or the risk of collision exceeds a predetermined level, can appropriate measures to avoid collision. For example, can an alarm is issued informing the operator, whereupon the operator can stop the device. Likewise the movement of the device be automatically stopped. Furthermore, the device may optionally execute an evasive movement for collision avoidance.

The preferred field of application of the method according to the invention is the monitoring of a medical treatment room with at least one movable medical device arranged therein, such. B. an X-ray device. The X-ray device may in particular be a C-arm, which will be described in more detail below.

Next In the method described above, the invention further relates to a Device for monitoring a spatial Area, in particular the environment of a movable medical device. The Device comprises a plurality of active distance measuring Detection means for the three-dimensional detection of the spatial Range. About that In addition, an evaluation unit is provided which from the detected spatial Area created a three-dimensional environment model, which Spatial volumes occupied by one or more objects in space Range specified. The device is in particular such designed such that each of the above-described variants of the method according to the invention feasible with the device is.

Embodiments of the invention are described below with reference to the attached 1 described. This figure shows a medical intervention room which is monitored based on an embodiment of the method according to the invention.

The method according to the invention is described below using the example of a medical intervention space R, which is shown in plan view in FIG 1 is shown. In the intervention space, an X-ray measurement with the aid of an X-ray device in the form of a so-called. C-arm 1 performed, with the movement of the C-arm to be monitored. The C-arm 1 includes a radiation source with collimator 1a at one end of the arc and a corresponding detector 1b on the other end. The C-arm can be moved or rotated in any direction in space via a positioning device (not shown). As a C-arm known from the prior art device can be used, for example, the model AXIOM Artis dFA Siemens AG. However, it is also possible to use any other X-ray devices, for example biplane systems with two C-arms, such as the model AXIOM Artis dBC from Siemens AG. Similarly, can be monitored with the inventive method Cartesian guided facilities, such. For example, the AXIOM Aristos FX Plus model from Siemens AG.

In the treatment room R is a patient table 2 provided on which the patient to be X-rayed is placed. Depending on the part of the body to be X-rayed, the C-arm is then moved to the appropriate X-ray position. In the treatment room R are also schematized monitors 3 indicated on which the X-ray images recorded by the C-arm are reproduced. There is also another medical device 4 in the form of an EEG (EEG = electroencephalography) at the foot of the patient table. During the radiographs, the treatment staff is protected by an X-ray shield 5 protected against X-radiation, the X-ray protective shield via a corresponding positioning device 6 can be positioned variably. The positioning device is attached to the ceiling of the room R. The current position of a doctor in the treatment room R is represented by an ellipse D and the current position of a wizard by an ellipse A.

The treatment room is covered by an array of four actively distance-measuring 3D cameras 7 . 8th . 9 and 10 monitors, with the angle of view of each camera is denoted by α. The cameras 7 and 8th are doing on a long side of the room R under the ceiling of the room and the cameras 9 and 10 positioned on the opposite longitudinal side of the room also under the ceiling. With the cameras, a part of the space is detected in three dimensions, wherein the detected part is an area in which increased activities occur due to the movement of the C-arm or the patient or the operator. For example, 3D cameras from MESA are used as cameras. Instead of such cameras, any other actively distance-measuring sensors can be used with which the spatial area can be detected three-dimensionally.

The individual cameras are equipped with a corresponding evaluation unit 11 connected, which generates from the captured images of the cameras, a three-dimensional environment model in which the space occupied by objects and in particular the C-space volumes are specified. By capturing a room area with direct distance measuring cameras or sensors a reliable and fast determination of this three-dimensional environment model is guaranteed. Optionally, further active range-measuring sensors may be present in the room for monitoring further areas, in particular sensors may also be attached to moving objects in the room, for example at the two front ends of the C-arm, to thereby monitor areas immediately in front of the C-arm , If, for example, pivotable laser scanners are used for the three-dimensional detection of a part of the room, these laser scanners preferably cover those regions of the room in which the greatest need for precise three-dimensional modeling is due to a presumed high activity.

The generated three-dimensional environment model is determined by the evaluation unit 11 appropriately processed, for example, to detect collisions. The environment model can also be on ei be visualized on a corresponding screen for an operator monitoring the room. Based on the generated three-dimensional environment model, the acquired space can be modeled in different ways. The space is preferably displayed in a volume grid with cells of variable resolution. A modeling of the room can z. B. by means of appropriate models (in particular geometric models) involving the persons and objects to be expected in the room to be performed. The models represent objects or arrangements of objects that are present or suspected in the room. These objects are stored in a database and by comparing the database with the environment model, occupied volumes of space can be identified as corresponding objects. For example, modeling can be based on dynamic models, ie models that can change over time in position and orientation in space and in their shape. In this case, information can be taken into account which indicates to what extent the validity of a model decreases with the passage of time. The models in particular describe the surface of the objects approximately, for example in the form of triangles. The models may also be focused in certain regions, for example in a region where more activities are occurring, such as the working space of a medical device, or in an area where there is a risk of intrusion of people or other devices in the workspace.

In an embodiment the space area detected by the cameras or sensors is subdivided in essentially the same size Volume volumes in the form of cuboids. From each measurement one directly Distance measuring sensor is detected directly, in which cubes the object causing the measurement or its surface with what probability is. In addition, you get one Statement about Which cuboid in the room with which probability is not occupied are. By clearing all this information, which of the various active distance-measuring sensors detected in the room eventually becomes one reliable Statement about it receive where objects are in three-dimensional space. Around Can save space possibly adjacent free (ie not occupied with objects) Cuboid to a larger cuboid be summarized.

In a preferred embodiment of the invention, it is considered that persons and objects in the space are essentially known a priori. In the medical intervention room according to 1 For example, it is known in advance that the patient is on the patient bed, and areas are also known in which the treatment staff preferably moves. It is thus possible to compare models of suspected persons or objects from a model database with the occupied volumes of space in which corresponding persons and objects are suspected. The occupied cells are then analyzed with which model from the model database they match, so that in the course of integration of the measurements in the three-dimensional model not only the occupied volumes, but also the objects characterized characterized are recognized. Thus, the environment model provides a scene description at a higher level, whereupon, for example, in a continuous monitoring of the room corresponding movements of the objects can be detected and possibly also the movement of the objects can be predicted.

The inventive method can be used in particular for collision avoidance. For example, the evaluation unit 11 in the embodiment of the 1 recognize the C-arm as an object and determine depending on predetermined criteria collision risks with the other detected objects. If a collision risk exceeds a certain limit or a risk of collision is detected, appropriate countermeasures can be initiated, for example, an alarm can be output by the evaluation unit. Likewise, the evaluation unit can be connected to the control of the C-arm, where given by the evaluation in Kollisionsgefahren a corresponding command to the C-arm, which triggers a stopping of the C-arm or an evasive maneuver of the C-arm.

Claims (19)

Method for monitoring a spatial area (R), in particular the environment of a movable medical device ( 1 ), in which: - with a plurality of actively distance-measuring detection means ( 7 . 8th . 9 . 10 ) the spatial area is detected three-dimensionally; A three-dimensional environment model is created from the acquired spatial area, which is defined by one or more objects ( 1 . 2 , ..., 6 , A, D) specified volume volumes in the spatial area (R) specified. The method of claim 1, wherein the spatial Area (R) with one or more actively distance-measuring 3D cameras and / or one or more pivotable laser scanners and / or one or more several ultrasonic sensors is detected. Method according to claim 1 or 2, wherein at least a part of the spatial Area (R), in particular the entire spatial area (R), by active distance-measuring 3D cameras is recorded and in addition a subarea of the spatial Area (R) detected by one or more pivotable laser scanner becomes. Method according to one of the preceding claims, in which the active distance-measuring detection means ( 7 . 8th . 9 . 10 ) are fixed in space and / or on one or more movable devices ( 1 ) are attached. Method according to one of the preceding claims, in the spatial Range (R) recorded as a picture stream of temporally successive images becomes. Method according to one of the preceding claims, in which each actively distance-measuring detection means ( 7 . 8th . 9 . 10 ) in a respective sub-section of the spatial area (R) which by one or more objects ( 1 . 2 , ..., 6 , A, D) detected volume volumes with a detection probability, taking into account the detection probabilities of all actively distance-measuring detection means ( 7 . 8th . 9 . 10 ) Space volumes in the three-dimensional environment model are specified as occupied. Method according to one of the preceding claims, wherein in the three-dimensional environment model, the space volumes as cuboid cells be specified. Method according to one of the preceding claims, in the adjacent, unoccupied volume of space to a volume of space be summarized. Method according to one of the preceding claims, in the occupied volumes in the three-dimensional environment model compared with three-dimensional object types from a database and based on the comparison result the room volumes Object types are assigned. Method according to one of the preceding claims, in which a movable device ( 1 ) is monitored in the space area (R), whereby the 1 ) occupied volumes in the three-dimensional environment model are identified. The method of claim 10, wherein based on the environment model, a risk of collision between the identified device ( 1 ) and one or more other objects ( 2 , ..., 6 , A, D) is determined. The method according to claim 11, wherein the determined collision risk is greater, the smaller a distance measure between the device ( 1 ) and the other object or objects ( 2 , ..., 6 , A, D) is in the room. Method according to claim 11 or 12, wherein in determining the risk of collision, the future direction of movement of the device ( 1 ) and / or one or more other objects ( 2 , ..., 6 , A, D) is detected in the room, whereby a risk of collision is determined if, assuming further movement of the device and / or the object or objects ( 2 , ..., 6 , A, D) a collision occurs in a certain period of time. The method of claim 13, wherein the future direction of movement from current and / or past movement directions of the device ( 1 ) and / or one or more other objects ( 2 , ..., 6 , A, D) and / or information about the movement to be performed by the device and / or the object or objects ( 2 , ..., 6 , A, D) is determined. Method according to one of claims 11 to 14, in which, in the event that the risk of collision exceeds a predetermined level, an alarm is output and / or the movement of the device ( 1 ) is stopped. Method according to one of claims 11 to 15, wherein in the event that the risk of collision exceeds a predetermined level, an evasive movement for collision avoidance by the device ( 1 ) is performed. Method according to one of the preceding claims, in which a medical treatment room (R) is provided with at least one movable medical device (R) arranged therein. 1 ), in particular an X-ray device is monitored. Device for monitoring a spatial area, in particular the environment of a movable medical device, comprising: - a plurality of actively distance-measuring detection means ( 7 . 8th . 9 . 10 ) for three-dimensionally detecting the spatial area (R); - an evaluation unit ( 11 ), which creates a three-dimensional environment model from the acquired spatial area, which is defined by one or more objects ( 1 . 2 , ..., 6 , A, D) specified volume volumes in the spatial area specified. Apparatus according to claim 18, which is designed in such a way is that with the device, a method according to any one of claims 1 to 17 is feasible.