DE102012205549A1 - Method for operating e.g. deadman switch in contactless controlled medical device e.g. C-arm x-ray device, involves detecting response signal by part of user, and operating switch depending on detected response signal - Google Patents

Abstract

The method involves projecting a request signal e.g. laser light signal, acoustic and/or optical signal, into an operation region (B) of a contactless controlled medical device (30). A gesture-based response signal is detected by a part of a user in response to the request signal. A safety switch (100) in the medical device is operated depending on the detected response signal. The request signal is projected by a laser projector out/or an infrared light transmitter. The reply signal is computed from positioning data of the user at predefined positions. An independent claim is also included for a system for operating a safety switch.

Description

The present invention is in the fields of safety engineering and medical technology and relates in particular to a method for operating a safety switch, in particular a dead man's switch or a switch for a motor-driven device in a medical device, and a related system.

For safety reasons, electrical installations and equipment, such as X-ray equipment, robots, patient table or detectors in different imaging systems, be protected by separate devices against accidental operation. This is especially important in devices of concern to human health, such as medical devices. These devices often include units which are automatically - e.g. by industrial robots - controlled and operated (such as robot operated units for positioning a C-arm of an X-ray machine). In the state of the art so-called dead man circuits are known from the field of work safety, which check whether a user is present and operational or require additional operating measures by the user to turn on or activate the device or units (especially in dangerous equipment in the tool or Medical technology, etc.). In order to ensure proper functioning of the respective device, it is important that these switches are protected against accidental operation.

In order to simplify the operation of devices and systems, it is further known in the art to provide non-contact control of the devices. This can be implemented, for example, by recognizing gestures of the user. Especially in this case it is important to make sure that no wrong gesture is detected as accidental operation.

In previous systems, special mechanical switches and pushbuttons have been used which have to be operated explicitly by the user. Usually, for example, it was provided that the switch for the entire duration of the operation of the respective motor-driven system must be kept pressed.

This procedure proves to be impractical, especially in non-contact controlled systems. Non-contact control systems typically use specific sensors and a motion detection unit with a 3-D camera, as well as specific computational processes to capture the gestures, movements, and activities of the respective operator. A field of application of non-contact control is medical technology, in which, for example, in the sterile operating room computer-aided actions can be controlled by gestures. Another area of application is manufacturing processes in cleanrooms.

The use of hand and arm gestures has long been a research topic in cybernetics. The algorithms for processing the gesture data are usually based on statistical methods, such as so-called Hidden Markov Models - HMM, Particle Filtering, Condensation, Finite State Machine (FSM) and neural networks. An overview can be found in: Mitra, T. Acharya, IEEE Transactions On Systems, Part C, Applications and Reviews, Volume 37, Number 3, May 2007, pages 311-324 ,

Furthermore, it is known to apply so-called set-top boxes in medical technology. The technique used is based on a gesture recognition technique, which is known in the field of game consoles or video games. For example, Microsoft uses the "Kinect" technology in the X-Box game console developed by Microsoft. Kinect technology relies on the use of an infrared light source to project certain patterns in space or on surfaces. The intervention of a body (e.g., hand or arm as part of a gesture) distorts the applied pattern. This distortion is detected by a camera and converted by means of processing software into a three-dimensional point cloud. With statistical methods and comparison with reference patterns, a movement can be recognized as a predefined gesture.

Based on the above-mentioned prior art, the object of the present invention is to protect non-contact controlled devices and / or systems from unwanted operation, which may occur, inter alia, by accidental operation of emergency switches. Furthermore, the safety of non-contact devices and systems to be improved.

This object is solved by the appended independent claims, in particular by the features of the method claim and the system claim and the claim relating to a control module. Advantageous embodiments and alternative embodiments are mentioned in the subclaims.

• – Projizieren eines Aufforderungssignals in einen Betriebsbereich des medizinischen Gerätes
• – Erfassen eines berührungslosen – vorzugsweise Gestenbasierten – Antwortsignals seitens zumindest eines Nutzers in Antwort auf das Aufforderungssignal
• – Betreiben des Schalters in dem medizinischen Gerät in Abhängigkeit von dem erfassten Antwortsignal.

According to one aspect, the present invention relates to a method for operating a safety switch in a Non-contact controlled medical device, such as an "MR system", a C-arm X-ray machine or subordinate mostly motorized devices of these systems, such as patient table, detectors, etc. The method comprises the following steps:

• - Projecting a request signal in an operating range of the medical device
• - Detecting a non-contact - preferably gesture-based - response signal from at least one user in response to the request signal
• - Operating the switch in the medical device in response to the detected response signal.

The terms used in this application are specified below.

The switch is preferably at least one operating element for controlling the device. Preferably, the switch has safety relevance, so that it must be protected against unintentional operation. It may, for example, be a deadman device, an emergency switch, a warning buzzer or switches that trigger risky, dangerous or health-critical processes (for example X-ray radiation, triggering of radiation of a different wavelength, application of a magnetic field, etc.). These switching elements have hitherto been operated exclusively mechanically in the prior art. The switch can assume two (ON, OFF) or more switching states. The switch may also comprise a combination of switching states and / or switches. In each case, a switch may optionally also control a plurality of functions of the device (for example movement of the patient table and activation of the radiation unit). The term "switch" is to be broadly understood and also includes providing a function or functionality that is activated or deactivated (such as turning on or off the patient table movability). In terms of safety, this also means "risky" so that the switch triggers a function with patient or operator risk. This feature is secured according to one aspect of the application.

The medical device can be imaging modalities (ultrasound device, CT system, magnetic resonance tomography, etc.) or components arranged therein, which are usually motor-driven. Usually, the medical device is connected via a network to other computer-based instances for the purpose of data exchange. The main embodiment relates to the field of medical technology. Alternatively, however, the invention can also be applied in other fields, such as the tool technology with the corresponding electrical equipment (CNC-controlled machine tools, etc.).

The request signal is preferably an optical signal that is applied by a projector in an operating range of the device. For example, a projector (e.g., a laser projector) may be added to the system to apply the prompt signal - for example, in the form of visually-visible laser pulses - to a predefined area. The prompt signal is used to prompt the user for a particular movement or gesture. For example, it is possible for visual signals to be applied to a specific area on the floor. On the basis of a determination, the doctor then knows that he must place himself exactly on this marked area if he wants to comply with the request signal. Alternatively, he can also touch the area marked by the request signal with the hand or with another body part or a tool. Furthermore, it is possible to apply the prompt signal in the form of a TARGET gesture (e.g., two crossed hands, raised hand, or preconfigured gesture combination) to an area (e.g., the wall). This TARGET gesture can then be answered by the user applying the actual gesture (ACTUAL gesture). Match of the desired and actual gesture is then executed by a gesture recognition algorithm implemented on a processor and forwarded to the switch as a control signal. The control command to be executed upon coincidence and mismatch (e.g., ON or OFF) may be preconfigured.

Via an automatic gesture recognition, the positioning or movement of the user is then detected as a response signal to the request signal. The request signal is transmitted according to one aspect of the invention to an evaluation unit, which determines whether the request signal has been answered by the user. Once the response signal has been detected, the operation of the switch can be automatically triggered.

The request signal is in each case assigned to a response signal according to an aspect of the invention. An alternative advantageous variant is to dispense with the request signal and to detect only a gesture-based response signal and to use for controlling the switch. This proves to be particularly advantageous in situations where the safety requirements are lower and the switch has a different functionality in the context of medical equipment (e.g., concerning the display of X-ray images).

The request signal may also comprise a sequence of signals. In this case, the respective request signal is assigned to a respectively corresponding response signal. For example, a request signal from a lighting of a first position and in consequence of the illumination of a second position. Only when both request signals are met (by corresponding movement to the respective position) and this response signal has been detected, the switch is operated. Of course, further juxtaposition of prompt signals can also be provided. Furthermore, other logical links between the individual request signals can also be taken into account (for example, required positioning at position 1 and no positioning in position 2, etc.). Preferably, the response signal is a gesture that is detected via automatic gesture recognition. Alternatively, the response signal may also include other types of signals (eg, optical, acoustic, etc.). The response signal may also consist of a sequence of response signals.

Usually, in each case a request signal is assigned to a respective response signal. In other words, a request to move to a certain position must be answered with the user's movement to the intended position. Only then can a second request signal be detected with a second response signal. Alternatively, a nested procedure can also be provided. A maximum allowable latency between the request signal and the corresponding response signal can be preconfigured.

As already mentioned above, in a preferred embodiment, the request signal is a projected light pattern which is applied, for example, by means of a laser projector. The pattern can either be projected onto an operating area in front of the medical device or in the working environment. The operating area is defined in advance and is preferably a certain area near the work area, which does not disturb the work, but at the same time is easily accessible. In medical applications, the operating area may be either an area on the floor in front of the medical device or an area near the surgical field, e.g. on the wall of the operating room. However, the operating area does not necessarily have to be a cutout on the floor or on a wall of the operating room. Alternatively, the pattern may also be applied to other non-moving surfaces (e.g., patient table, etc.).

In an advantageous development of the invention, the request signal can also be projected onto parts of the body of the user (for example hands or feet). This can preferably take place if the user executes a specific trigger signal. The trigger signal may be an acoustic or a gesture signal, which is executed, for example, in the context of a predefined pose and initiates the automatic gesture control. For example, it is possible for a moving arrow to be projected onto the surgeon's palm to indicate that he needs to move in the direction of the arrow to answer the prompt signal accordingly. If the doctor then moves his hand in the direction of the arrow (possibly also repeated several times), this is detected as a response gesture and transmitted to the system. Thus, the TARGET gesture can also be projected onto the user himself and prompt him to deliberately execute the projected gesture (eg, slowly move the arm to follow the direction of a hand-applied arrow), which then automatically detects as an ACTUAL gesture and is processed to control the device.

In an advantageous development, it can be provided that the request signal additionally comprises an acoustic and / or a visual signal. This serves to give the doctor, in addition to the application of the pattern, further trigger signals (acoustically and / or visually), which inform him that a request for the input of a response signal is expected from him.

The prompt signal is generated in a preferred embodiment by a laser projector. Alternatively, an infrared light source can also be provided here and a corresponding infrared sensor can be used to automatically detect the gesture.

The response signal preferably includes a gesture of the user. The gesture can be triggered by an arm and / or hand movement. For example, the hand gesture may be a wiping motion that triggers scrolling between different pages (e.g., to display different x-ray images). Alternatively or cumulatively, the response signal may also include an audible signal. For example, it is possible for the doctor to support his gesture by entering an appropriate command in an acoustic form. Usually, the response signal is triggered by a gesture of the doctor. For this he can either move his feet to a predefined position on the floor of the operating room or he can move his hand to a predefined position. It is also possible that he uses pointing elements for this (e.g., pointing stick or laser pointer, etc.). Thus, the security of the system can be increased by processing additional signals in addition to the gesture recognition.

The invention is based on automatic gesture recognition and control. However, since medical technology is a safety-critical application, in particular in the operational environment, it is provided according to the invention that the control or the operation of the switch is not triggered solely by the gesture. Rather, it is provided that initially a request signal - as a challenge - is generated and transmitted, which can then be answered by a predefined gesture - response. One aspect is therefore to be seen in a gesture-based challenge-response procedure.

The system is very flexible and can be adapted to different applications. It is thus possible, for example, to configure in advance that the switch is operated only when a specific (predefined) response gesture is detected in response to the request signal. The operation of the switch, in turn, can be configured differently: it includes switching on and off. In other words, it can be provided that the switch is turned on, if the doctor answers by a corresponding gesture, the request signal. Alternatively, the switch can also be switched off. It is also possible to provide here further adjustment measures on the switch, if he knows more than two switching states. In other applications, it may be provided that the operation of the switch is caused if no response signal has been detected. This is particularly useful if the switch is a specific emergency switch that should only be operated in very specific situations. Thus, if a request signal from the system remains unanswered, it may be preconfigured that the device remains in operation and not turned off. In certain situations, the operation of an emergency stop switch may also be controlled by the gesture-based challenge-response method described above.

An essential aspect of the present application relates to protecting a system or device from unwanted operation. This can be ensured by the switch can be operated or operated only after successful execution or answering the Posture Challenge.

In particular, in the context of a medical operation, it is important to alert the persons involved that they are in a hazardous area (for example, an area that must not be entered because it must remain sterile). Other applications (such as the transport or processing of dangerous goods) may define appropriate hazard areas. The method and system described above, according to an alternative embodiment of the invention, may also be used to alert the users that they are in the danger zone and to request the alert signal to move out of the danger zone. The response signal, in one embodiment, is configured to signal, as it were, a missing gesture or absence of the user in the danger area. In other words, the response signal is only triggered and forwarded to the system for calculation, if it is ensured that no person is in the danger zone and necessary persons in the operating area. You can also configure a predefined time interval that is managed.

In a further variant of the invention, provision may be made for defining specific positions at which the person is to be positioned. The response signal is only triggered when the respective person is in the assigned position. In the above-mentioned embodiments, the switch may relate to the switching on or switching on of a device. In other words, the device is turned on only when no person is in the danger zone and / or all persons are at their assigned positions.

The gesture recognition method preferably uses a reference model in which desired gestures and / or desired positions are stored. The current actual position is then compared with the nominal position for agreement. Only if the actual position and setpoint position match, the switch is switched to a ready state.

Usually, it is provided that the operation and / or control of the switch is triggered by the projecting of the request signal. In this variant, the method is thus triggered by the system. Alternatively, however, it may also be provided that the user (for example a doctor) triggers the procedure. Therefore, it is provided in an alternative embodiment of the invention that initially a trigger or trigger signal is detected. The triggering signal is preferably triggered by the user and may be an audible or a gesture signal. Only when this signal is detected by the system and / or the medical device, a request signal is generated and sent. This embodiment has the advantage that no unnecessary request signals are triggered and the commissioning of the respective switch is executed only when needed.

In order to further increase the security of the system, it is provided in a further embodiment of the invention that ensures can be that the respective gesture that serves as a response signal is not carried out in the context of a normal operation (or in the context of surgical intervention) anyway. To do this, the method uses a kinematic model to define specific gestures that require a specific motion pattern that is not used in normal operation. Furthermore, however, it should be ensured that this gesture is simple and also feasible for the respective user (regardless of its size and stature, etc.). The respective kinematic model is thus based on statistical body and movement models of an "averaged" user.

• – Einen Aufforderungssignalsender, der beispielsweise eine Infrarotlichtquelle oder ein Projektor sein kann. Der Aufforderungssignalsender dient zum Projizieren des – vorzugsweise optischen – Aufforderungssignals.
• – Das System umfasst desweiteren eine Gestenerfassungseinheit, die zum automatischen Erfassen einer Geste dient. Die Geste wird als Antwortsignal auf das Aufforderungssignal gewertet und dem System zur weiteren Verarbeitung zugeführt. Der Schalter wird dann ausschließlich in Abhängigkeit von dem erfassten Antwortsignal gesteuert. Wie die Steuerung des Schalters ausgebildet ist, kann voreingestellt sein. Beispielsweise kann bei Erfassen eines entsprechenden Antwortsignals der Schalter in Ein-Stellung oder in Aus-Stellung geführt werden.
• – Die Gestenerfassungseinheit umfasst neben der Projektionseinrichtung bzw. neben dem Projektor eine Kamera, insbesondere eine CCD-Kamera. Die Kamera dient zum Erfassen einer Folge von sogenannten Tiefenbildern, um zumindest einen Bereich einer personenähnlichen Kontur zu ermitteln. Die Folge von Tiefenbildern wird einem Computer zur Verarbeitung zugeführt.
• – Gemäß einer bevorzugten Ausführungsform der Erfindung umfasst das System ein Steuerungsmodul, das zur Steuerung des Schalters bestimmt ist.

The invention is further achieved by a system for operating a safety switch in a non-contact controlled medical device. It will be apparent to those skilled in the art that not only one switch but also multiple switch combinations can be operated. The system includes:

• A request signal transmitter, which may be, for example, an infrared light source or a projector. The request signal transmitter is for projecting the - preferably optical - request signal.
• The system further includes a gesture detection unit for automatically detecting a gesture. The gesture is evaluated as a response signal to the request signal and fed to the system for further processing. The switch is then controlled solely in response to the detected response signal. How the control of the switch is designed can be preset. For example, when detecting a corresponding response signal, the switch can be guided in the on position or in the off position.
• - The gesture detection unit comprises in addition to the projection device or next to the projector, a camera, in particular a CCD camera. The camera is used for detecting a sequence of so-called depth images in order to determine at least one region of a person-like contour. The sequence of depth images is fed to a computer for processing.
• According to a preferred embodiment of the invention, the system comprises a control module which is intended to control the switch.

Another task solution relates to the control module adapted for use in a system.

Portions of the above-mentioned method may be computer-based and implemented by software. Alternatively, it is possible that the respective functionality is implemented by hardware components, e.g. through microprocessor modules etc.

The above-described features, advantages, and features of the invention, as well as the described embodiments and alternatives, will be more clearly understood in connection with the description of specific embodiments which will be further described in connection with the following description of the embodiments in conjunction with the drawings. In the drawing shows:

1 an overview, schematic representation of a non-contact control system for controlling safety functions on a medical device

2 a schematic representation of exchanged signals between the user and a medical device with a safety switch and

3 a flowchart according to a preferred embodiment of the invention.

The invention will be explained below with reference to FIG 1 explained in more detail.

The main field of application of the present invention is the medical technology, so that the method mainly the control of safety switches 100 in medical technology systems 30 concerns.

According to the invention the plant 30 controlled without contact. To ensure that safety-critical functions (such as deadman devices) are not inadvertently operated, mechanical switches have hitherto been provided which, inter alia, must be kept pressed for a specific time interval in order to trigger the specific function. However, the actuation of a mechanical switch proves to be less practicable especially in non-contact systems. At this point, the invention starts and proposes a method for the non-contact control of dead man's switches 100 in front.

As in 1 represented is the user who is in 1 only schematically indicated in an operating room. The system includes a projector 10 which is configured to project a request signal into an operating region B. Furthermore, the system includes a camera 12 , In particular, a CCD camera to detect gestures of the user. The projector 10 and the camera 12 are in communication with a computer 20 , The computer 20 is in turn in data exchange with the medical device 30 , In 1 an example of a C-arm X-ray device is shown. However, this should only be an example; The invention may also be applied to other imaging modalities or other medical devices. It is also possible that only individual components of the medical device 30 through a safety switch 100 be addressed. The safety switch 100 is in a preferred embodiment directly into the medical device 30 integrated. Alternatively it is possible that the switch 100 multiple components or multiple devices 30 on.

Usually, the switch has 100 two states: an on state and an off state, and thus can distinguish between two binary states. Alternative versions see a switch 100 which can also take on more than two states.

How out 1 can be seen, a request signal is projected onto the operating area B. The operating area B is a predefined area used to control the switch 100 is determined. The positioning of area B is in a preferred embodiment beforehand configurable. In other words, a configurator or a system administrator can determine in advance where the operating area B should be arranged. For example, this may be a certain area on the floor of the operating room or a certain wall area. It is also possible to define other stationary elements as operating range. Alternatively, a mobile area, for example a body part of the physician, can also be defined as operating area B (eg his hand or his arm, this has the advantage that the doctor is necessarily aware of the request signal A).

The following is the data exchange with reference to 2 explained in more detail. On the left side of 2 the doctor is pictured while on the right side of the computer 20 and the device 30 with the switch 100 are arranged. In the attribution area of the user two areas are marked. On the one hand, the operating region B and an effective region W. In a preferred embodiment, it is provided that the request signal A by means of the projector 10 projected on the operating area B. The request signal A is to be understood as a request to the user, a control command for the switch 100 trigger. The control command should be recorded without contact. This is preferably done by a gesture and automatic gesture recognition. In the first embodiment, the request signal A is answered by entering the operation area B by the user. The request signal A may be formed as a laser light signal or as a result of laser light signals. It is applied to the operating area B. The request signal A is answered in this first embodiment in that the user enters the operation area B. In this embodiment, therefore, the answering gesture is entering the operating area B. This is done by the camera 12 detected and as a response signal B the computer 20 fed for further processing. The computer 20 accesses mechanisms for automatic gesture recognition and recognizes that the user has sent by entering the operating area B a corresponding response signal B as feedback to the request signal A. This is considered a corresponding control measure to the switch 100 of the device 30 to switch. Which switching state should be taken here can be configured. Usually, it is intended that the device 30 in the operating state. The operating state is maintained until the user instructs a modified control by a corresponding gesture. Thus the control of the switch 100 can also be triggered by the user, it is provided in a preferred embodiment of the invention that first a trigger signal T from the user to the computer 20 is transmitted. The trigger signal T may be an optical, acoustic and / or a gesture-based signal. The trigger signal T is preferably defined in advance. After receiving the trigger signal T from the computer 20 The request signal A is automatically generated and applied or sent. As soon as the user then enters the operating area, this is evaluated as a response signal B and from the computer 20 processed accordingly to a state change of the switch 100 to effect.

In a second embodiment, the response signal B is formed by an arm and / or hand gesture. For this purpose, the effective range W is defined in advance, which comprises a certain volume range. The response signal B is then detected as a gesture of the user in the effective range W.

In a variant of the invention, effective range W and operating range B can coincide or have overlapping ranges. In an alternative embodiment of the invention, the effective range W is separated from the operating range B.

In a further variant of the invention, both of the variants described above can also be combined. In this embodiment, it is provided that the request signal A is applied to the operation area B. If the user now wants to change the device state, two steps are necessary. First, it requires that he enters the operating area B. Once this is detected by the system, a second request signal A can be sent that the Users in turn can answer by a hand gesture. The hand gesture is carried out in the effective range W. The gesture may be, for example, a swipe, a click, the operation of a continue function, a back function, a stop function, etc. This second gesture is then sent as a second response signal B to the computer 20 transfer. Only when both response signals B are obtained, a state change or a corresponding control of the switch 100 triggered.

The following is with reference to 3 a possible sequence according to a preferred embodiment shown.

After the start of the system takes place in step 70 the generation of a request signal A. This is preferably a visible, visual signal (eg laser light projection or ultrasound signal, etc.).

In step 71 the generated request signal A is projected into the operation area B.

In step 72 a gesture of the user (eg, foot positioning, arm positioning, arm gesture, hand gesture) is detected as a response signal B.

The response signal B is in step 73 forwarded to the computer for further processing.

In step 74 the response signal B is processed. The switch is activated in response to the response signal B. 100 operated. Operation in a preferred embodiment includes a change of state from ON to OFF or from OFF to ON. The operation of the switch takes place in step 75 , Then the procedure ends.

As in 3 indicated, it is possible that after processing the response signal B in step 74 to step 72 is branched back. This is particularly useful if the response signal could not be completely resolved and processed and a repeated capture of the gesture is required. Likewise, in general error case, the repeated execution of the gesture may be required. Likewise it is possible that the procedure is completely repeated, so that already to step 71 is branched and the procedure from step 71 is repeatedly executed.

In principle, it should be emphasized that the flexibility of the method can also be increased by the fact that certain configuration measures are taken in advance. Thus, for example, it can be set in advance which state change is to be carried out in which response signal B. Furthermore, it is possible to configure here that further notes are sent to other instances. Thus, for example, upon receipt of a response signal B, an alarm signal (eg also in audible or visual form) can be triggered to alert the personnel to triggering the switch 100 to point. Furthermore, other computer-based instances that are in data exchange with the system can be informed. In the preparation phase can also be configured in what form the response signal B is to be detected. In other words, it can be defined here which gesture should serve as the response signal B. It is possible to enter the operating area B or to execute a predefined gesture (hand or arm), which is compared with the reference gestures for agreement by comparison. In this case, the operating range B and the effective range W differ.

In another embodiment variant of the invention, the request signal A can be applied to a passive operating region B. In this embodiment, the operation area B is characterized only by being "lit" when the request signal A is to be sent. The request signal A can then be answered with a gesture in the effective range W, as the response signal B to the computer 20 is forwarded.

As mentioned above, alternatively, operating region B and effective region W may have overlapping regions. This is particularly the case when the request signal A is applied to the back of the hand or the user's arm, which is then later to execute the corresponding, predefined gesture, which is evaluated as a response signal B.

However, the above-described principle can also be applied differently - in a mathematical sense - by testing and ensuring that a user or a predefined circle of users actually and at a certain point in time can be checked in a medical environment in a safety-critical system a preconfigured, possibly user-specific operating range of the system or device 30 located. Under certain circumstances, the operation of an emergency stop switch come into consideration, which is then activated if a request signal A is not answered accordingly.

A number of advantages are achieved with the present invention. The safety of operation can be increased by the fact that unintentional operation of safety-related switches can be avoided. Furthermore, the operation of non-contact controlled devices simplified and improved. An important point in practice is the fact that the system can be adapted very flexibly to the particular application, for example, in which configuration settings are possible in advance (type of the request signal A and / or the response signal B, choice of the operating range B and / or the effective range W, control or operating behavior of the switch 100 Etc.).

Finally, it should be noted that individual modules can also be designed as software and / or hardware modules, and the exemplary embodiments are in principle not restrictive with regard to a specific physical realization of the invention. For a person skilled in the art, it is particularly obvious that the invention can be implemented partially or completely in software and / or hardware and / or on a plurality of physical products - in particular also computer program products.

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 non-patent literature

• "Gesture Recognition: A survey" S. Mitra, T. Acharya, IEEE Transactions On Systems, Part C, Applications and Reviews, Volume 37, Number 3, May 2007, pages 311 to 324 [0006]

Claims (10)

Method for operating at least one safety-related switch ( 100 ) in a non-contact controlled medical device ( 30 ), comprising the following method steps: - projecting a request signal (A) into an operating region (B) of the medical device ( 30 ) - Detecting a gesture-based response signal (B) by at least one user in response to the request signal (A) - Operating the switch ( 100 ) in the medical device ( 30 ) in response to the detected response signal (B). Method according to Claim 1, in which the switch ( 100 ) a safety function of the medical device ( 30 ). Method according to one of the preceding claims, in which the request signal (A) comprises a sequence of request signals to which respective corresponding response signals (B) are assigned. Method according to one of the preceding claims, in which the request signal (A) comprises an acoustic and / or optical signal. Method according to one of the preceding claims, in which the request signal (A) is projected by means of a laser projector from / or an infrared light transmitter. Method according to one of the preceding claims, in which the response signal (B) is calculated from positioning data of the user at predefined positions. Method according to one of the preceding claims, in which the response signal (B) is detected as part of an automatic gesture control. Method according to one of the preceding claims, in which the response signal (B) serves to detect whether at least one person is located in a predefined danger area and only if so, a response signal (B) is triggered, which then controls the switch ( 100 ) triggers a deadman circuit in particular. System for operating at least one safety-related switch ( 100 ) in a non-contact controlled medical device ( 30 ), comprising: - a request signal transmitter ( 10 ) for projecting a request signal (A) into an operating area (B) of the medical device ( 30 ) - A gesture detection unit ( 20 ) intended for detecting a gesture-based response signal (B) on the part of at least one user in response to the request signal (A) - A control module adapted to operate the switch ( 100 ) in response to the detected response signal (B). Control module for use in a system according to claim 9, which is incorporated in a medical device ( 30 ) or on an external instance as a plug-in to the medical device ( 30 ) is formed hinzuschaltbar.

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