Abstract:
The present invention relates to devices, system and method for detecting gestures. The devices, systems and methods uses optically shape sensing devices for tracking and monitoring users. This allows unhindered, robust tracking of persons in different setting. The devices, systems and methods are especially useful in health care institutions.

Description:
CROSS-REFERENCE TO PRIOR APPLICATIONS 
     This application is the U.S. National Phase application under 35 U.S.C. §371 of International Application Serial No. PCT/IB2013/053479, filed on May 2, 2013, which claims the benefit of U.S. Provisional Application Ser. No. 61/645,097, filed on May 10, 2012. These applications are hereby incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to gesture control systems and methods. Especially the present invention relates to gesture control systems and method for use in health care institutions. 
     BACKGROUND OF THE INVENTION 
     Interacting with computers can be done in a number of ways, including using a mouse or keyboard. In some situations, however, it is preferable to use a touch-free control unit. Such a control system could be a voice controlled system, but voice control is not always sufficiently accurate and precise. The inventor of the present invention has appreciated that an improved control system and method is of benefit, and has in consequence devised the present invention. 
     SUMMARY OF THE INVENTION 
     Robustness of systems for controlling imaging systems and other medical devices using operator gestures depends on the volume of sensor data and the type of sensor. Current gesture control methods have drawbacks, e.g., a camera-based system needs a line-of-sight and an ultrasound based system is useful only for short range. Another limiting factor is that for most sensor approaches, it is difficult to track, for example, an operator&#39;s entire arm. 
     The present invention proposes a garment enabled with optical shape sensing that tracks, amongst other things, extremities of an operator, e.g. arms, head, hands, fingers, or any optical shape sensing enabled device, preferably in combination with a system, wherein a pattern recognition scheme is applied to evaluate the recorded gestures for event detection in real-time. 
     It would be advantageous to achieve a control system where touch-free control allows precise and robust inputs to a device, e.g. a computer. 
     In general, the invention preferably seeks to mitigate, alleviate or eliminate one or more of the above mentioned disadvantages singly or in any combination. In particular, it may be seen as an object of the present invention to provide a method that solves the above mentioned problems, or other problems, of the prior art. 
     To better address one or more of these concerns, in a first aspect of the invention a garment to be worn by a person, e.g. a health care person, to be monitored is presented that comprises an optical shape sensing device affixed to and running throughout the garment so that shape changes and/or movement of a part of the garment is reflected as a shape change in the optical shape sensing device, wherein the optical shape sensing device is sewed up in, or affixed to, the garment so as to monitor motion. 
     By utilizing a garment having a trackable shape sensing device embedded or affixed to the garment the drawbacks of a camera-based system needing a line-of-sight and an ultrasound-based system being useful for short range only, are eliminated. Another limiting factor which is overcome is that for most sensor approaches, it is difficult to track, for example, an operator&#39;s entire arm. By the present invention it is possible to track an entire arm. This allows for a more precise recognition of gestures. Further, it is contemplated that gesture commands may include movement of more parts of the arm, e.g. combined by upper and lower arm and/or hand. The garment allows monitoring of a person wearing the garment in a robust way. The garment provides possibility of recognition of movement patterns of the person wearing the garment whereby the person is allowed to interact with equipment in a touch-free way. 
     Using the garment, or the instrument, it is possible to control a range of equipment including, but not limited to, an imaging system, e.g. allowing the wearer to change or manipulate images being displayed, a surgical instrument, for instance a catheter or interventional or surgical probe or robot or an injector for contrast agent, a data set being displayed on a screen or any other instrument or equipment that a surgeon may wish to operate in an easy and intuitive manner without having to touch the device to control it. More examples will be given below. 
     The present invention may also include audio and/or visual and/or haptic feedback to confirm gesture interpretation and command execution. Further, the system, garment, instrument and method may employ a mode switch so as to toggle gesture control state on and off during an intervention. Also a confirmation step may be used before a recognized command is executed. 
     When using the garment in a health care institution, especially in a surgical setting, the garment provides intuitive control, and improved workflow due to reduced interaction with the clinical staff handling viewing workstations. It is currently imagined that the system is well suited for examples in medical imaging which in general includes image browsers controlled by gestures. This could e.g. be prerecorded pre-interventional imaging including but not limited to CT, MR, X-ray, Ultrasound imaging or live X-ray images, MR-images, CT images, ultra sound images of a patient undergoing, or scheduled to undergo, surgery or other medical procedure. 
     In an embodiment the optical shape sensing device comprises a flexible body having a cross-section being comparatively small relative to the length of the device, the optical shape sensing device configured to determine the shape of the flexible body relative to a reference, the shape sensing device configured to collect information based on its configuration to track movement and/or current shape of the flexible body. When the optical shape sensing device comprises a flexible body, the optical shape sensing device is able to follow the movements of the person wearing the garment while having an increased strength. 
     Advantageously the optical shape sensing device is integrated in a part of the garment corresponding to an extremity of a person wearing the garment. As mentioned above it is contemplated to be especially useful to integrate the optical shape sensing device in an extremity as these are the most efficient to move purposely. Extremities include arms, head, hands and/or one or more fingers. Tracking the torso of a person alone could yield detection of unintended movement patterns corresponding to a given command or event. Combining movement pattern recognition of torso and one or more extremities provides a wider range of combination s allowing more commands or events to be defined. Tracking at least one extremity allow for an intuitive control of the device to be controlled. 
     In an embodiment the garment is a surgical gown and the optical shape sensing device is located in one arm of the surgical gown. The integration of the optical shape sensing device in a garment for use in surgical gowns is especially useful as in such settings the need for reducing contact to maintain sterility is quite high. Eliminating contact between the surgeon and any equipment reduces the risk of contamination, e.g. from insufficient cleaning of the equipment. 
     Advantageously the garment may comprise a connector for connecting the optical shape sensing device to a control computing device generating gesture events based on position information from the optical shape sensing device. The garment is advantageously used for generating commands or instructions for a computing device, e.g. an imaging device for use in a surgical setting. 
     A second aspect relates to a surgical instrument comprising an optical shape sensing device disposed within the surgical instrument and configured to determine a shape and/or position of the surgical instrument relative to a reference, the optical shape sensing device configured to collect information based on its configuration to during a procedure. Gestures may be detected based on detecting maneuvers of tracked medical devices, such as surgical instruments including but not limited to a shape sensing enabled catheter, which for instance could be used to trigger an infusion if the physician performs specific actions. An example could be a clockwise rotation by 180 degrees or fast movements detectable by applying pattern recognition. The optical shape sensing device may in this relation also be an optical position sensing device. 
     Advantageously the surgical instrument may be a flexible instrument including a catheter and/or a guidewire. 
     In an embodiment the surgical instrument may comprise a connector for connecting to a control computing device generating gesture events based on position information from the optical shape sensing device. The surgical instrument may be connected directly to a control computing device performing gesture pattern recognition or be connected to a garment according to the first aspect of the present invention so that a system for pattern recognition correlates patterns recorded for the surgical instrument with patterns detected using the garment. 
     A third aspect of the present invention relates to a gesture pattern recognition system comprising a garment to be worn by a human to be monitored, the garment comprising: an optical shape sensing device affixed to and running throughout the garment so that shape changes and/or movement of a part of the garment is reflected as a shape change in the optical shape sensing device, wherein the optical shape sensing device is sewed up in, or affixed to, the garment so as to monitor motion, the shape gesture pattern recognition system receiving a signal from the optical shape sensing device and the shape gesture pattern recognition system generating a gesture event based on the signal from the optical shape sensing device. The optical shape sensing device allow for tracking of movement of the person wearing the garment and the system as a whole may then be used for monitoring if/when the person wish to issue a command or instruction to a computing device, such as an image display device. The system provides accurate and robust monitoring of movement without limitations of line of sight. 
     A fourth aspect of the present invention relates to a gesture pattern recognition system comprising a surgical instrument comprising an optical shape sensing device disposed within the surgical instrument and configured to determine a shape and/or position of the surgical instrument relative to a reference, the optical shape sensing device connected to the shape gesture pattern recognition system to collect information based on a signal from the optical shape sensing device relating to the configuration of the instrument to during a procedure, the shape gesture pattern recognition system creating gesture events based on the signal. The optical shape sensing device is used for monitoring movement of the surgical instrument. The person operating the surgical instrument may wish to issue a command to create a gesture event. As an example a shape sensing enabled catheter could be used to trigger an infusion if the physician performs specific actions such as clockwise rotation by 180 degrees or fast movements detectable by using a system according to the applying pattern recognition 
     A fifth aspect of the present invention relates to a method for controlling a shape gesture pattern recognition system comprising an object with an optical shape sensing device, wherein the shape gesture pattern recognition system is configured to determine a shape and/or position of the object relative to a reference, the method comprising the steps of detecting a gesture pattern of the object, determining if the gesture pattern of the object corresponds to one of a set of recognized gestures, if the gesture pattern is recognized generating a gesture event based on the recognized gesture, and operating a device based on the gesture event. The method allows monitoring of a person wearing a garment having an optical shape sensing device. The method provides recognition of movement patterns of the person wearing the garment whereby the person is allowed to interact with equipment in a touch-free way. The method may advantageously be used in connection with the devices and systems mentioned in relation to the other aspects of the present invention. 
     Advantageously the object is a garment and the optical shape sensing device is integrated or affixed to the garment, the method may then comprise detecting gesture patters of the person wearing the garment. The gesture patterns are used for generating gesture events which in turn is used for controlling a device. The device could be an imaging device as described elsewhere. 
     Advantageously when the object is a surgical instrument comprising an optical shape sensing device disposed within the surgical instrument and configured to determine a shape and/or position of the surgical instrument relative to a reference, the optical shape sensing device may be configured to collect information based on its configuration to during a procedure. When applying the method to a surgical instrument the method allows the operator of the instrument to issue touch-free commands. The commands could relate to a shape sensing enabled catheter to trigger an infusion via the catheter. 
     Advantageously detecting the gesture pattern may include detecting discrete events and/or quantitative metrics including velocity and/or acceleration. By applying discrete events, e.g. detecting that an arm moves in a specific manner or movement pattern of a hand, the method allows definition of movements that are not usually part of the operators normal behavior. The same apply to detection of quantitative metrics. 
     Advantageously detecting discrete events may include detecting motion of extremities of a person wearing the object. As mentioned the method may advantageously focus on the movement of an extremity, or several extremities, e.g. arm, leg, hand, finger, head or combinations thereof. 
     In all of the above aspects the following may apply to the optical shape sensing device. 
     Advantageously the optical shape sensing device may include an optical fiber having at least one of Fibre Bragg Gratings (FBGs) and/or a Rayleigh scatter interrogation setup for sensing strain in the fibre. The use of optical fibre or optical fibres allow for the device to be flexible. Other suitable materials or structures may be envisioned. 
     Advantageously the optical shape sensing device includes an area of higher sensitivity by including an area with a higher number of optical fibres having optical strain sensors. E.g. optical shape sensing device may have one area where one number of optical fibres having optical strain sensors are present, in another are another number of optical fibres having optical strain sensors is present, and thus an area having of higher sensitivity may be established. The higher sensitivity may help achieve a better resolution on the determination of the position of the device. It may be advantageous to have an area having one optical fibre having optical strain sensors defining an area having a first sensitivity, and another area having four optical fibres having optical strain sensors defining an area having a second sensitivity being higher than the first sensitivity. 
     Advantageously the optical shape sensing device may include one, or more, of a spiral shape, a ring shape, a straight or curved line and/or a loop shape. The different devises provide different effects e.g. better fitting to a specific organ and/or tumour, and the specific choice may depend on the intended clinical application. 
     In general the various aspects of the invention may be combined and coupled in any way possible within the scope of the invention. These and other aspects, features and/or advantages of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will be described, by way of example only, with reference to the drawings, in which 
         FIG. 1  is a schematic illustration of a principle used in the present invention, 
         FIG. 2  is a schematic illustration of a health care setting, 
         FIG. 3  is a schematic illustration of a system including a surgical instrument, 
         FIG. 4  is a schematic illustration of a system including a garment, and 
         FIG. 5  is a schematic illustration of steps of a method according to the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Gesture control is gaining attention in the medical market due to advantages such as touch-free control, which is important for maintaining sterility, intuitive control, improved workflow and the like. Gesture control robustness, however, depends on the amount of sensor data and the type of sensor: e.g a camera-based system suffers line-of-sight issues. That is to say, the camera must have an unobstructed view on the tracked object, e.g. the arm or hand of a person. An ultrasound based system is useful only for short range applications. For most sensor approaches it is difficult to track, for example, the entire arm of an operator. 
       FIG. 1  schematically illustrates one principle used in the present invention where an optical fiber is used as an optical shape sensing device. In practice, optical fiber  20  may be any type of optical fiber suitable for optically tracking elongated device. Examples of optical fiber  20  include, but are not limited to, a flexible optically transparent glass or plastic fiber incorporating an array of fiber Bragg gratings integrated along a length of the fiber as known in the art, and a flexible optically transparent glass or plastic fiber having naturally variations in its optic refractive index occurring along a length of the fiber as known in the art (e.g., a Rayleigh scattering based optical fiber). Optical fiber  20  may be a single core fiber or preferably, a multi-core fiber. 
     Overall  FIG. 1  schematically illustrates the principles of a system  10  for optical frequency domain reflectometry using a tuneable light source  30  and a fiber-optic interferometer. The output of the light source  30  travels through a splitter  40  which directs a part of the signal into a reference arm  50  and the remaining part of the signal into a sample arm  60  which illuminates and receives the light reflected at the area  70 . 
     The interference between the signal returned from the reference arm and the signal returned from the sample-arm is detected with a square-law photo detector  80  while the wavelength of the monochromatic source is swept and the path lengths of the reference and sample arm are held constant. The axial reflectivity profile (A-line) is obtained by discrete Fourier transform (DFT) of the sampled detector signals. 
     In practice, elongated device  20  may be any type of device suitable for embedding an optical fiber therein for purposes of optically tracking the elongated device. Examples of elongated device  20  include, but are not limited to, an endoscope of any type, a catheter and a guide wire. Further the elongated device  20  may be embedded or attached to a garment. 
     In practice, optical interrogation console  30 , including the light source, may be any device or system structurally configured for transmitting light to optical fiber  20  or  60  and receiving reflected light from optical fiber  20  or  60 . In one embodiment, optical interrogation console  30  employs an optical Fourier domain reflectometer and other appropriate electronics/devices as known in the art. 
       FIG. 2  schematically illustrates a garment  100  worn by a health care person to be monitored. The garment  100  comprises an optical shape sensing device  110  affixed to and running throughout the garment  100  so that shape changes and/or movement of a part of the garment  100  is reflected as a shape change in the optical shape sensing device  110 , wherein the optical shape sensing device  110  is sewed up in, or affixed to, the garment  100  so as to monitor motion. This allows unobstructed monitoring of the person using the garment  100  whereby detection of specific movement patters is possible. In  FIG. 2  the garment  100  is a surgical gown and the optical shape sensing device  110  is located in one arm of the surgical gown. 
     Fiber-optic shape sensing  110  when contained in a flexible substrate such as textile of a garment can be used to track gestures of an operator wearing the sensing enabled garment. If the shape sensor is embedded e.g. in the arm sleeve of the operating apron, the entire arm can be tracked without any sensor limitation such as line-of-sight, or operating field size. 
     The relative accuracy of Optical Shape Sensing (OSS) is good enough even at extended tether lengths of more than three meters for gesture control and movement pattern recognition, allowing for enough cable length to connect garment  100 . The garment  100  may be connected to equipment via the operating table  120  or directly to a control system. Preferably the connection is via a cable  130  as there may be risks involved when using a wireless connection, but it is not excluded that the garment  100 , or optical shape sensing device  110 , may be connected wirelessly. 
     Another advantage of optical shape sensing especially compared to the more established Time Of Flight (TOF) technology is that even small deformation can be tracked. This is particularly important as one current problem of TOF based gesture control is that large movements have to be performed to do the control which is difficult to accept in the operating room. This is not always desirable in operating theaters. 
     The optical shape sensing device  110  comprises a flexible body having a cross-section being comparatively small relative to the length of the device, and the optical shape sensing device  110  is configured to determine a shape of flexible body relative to a reference, the shape sensing device  110  configured to collect information based on its configuration to track movement and/or current shape of the flexible body. This is also possible via the arrangement illustrated in  FIG. 1 . 
     Gestures can also be detected based on detecting maneuvers of tracked medical devices. E.g. a shape sensing enabled catheter could be used to trigger an infusion if the physician performs specific actions such as clockwise rotation by 180 degrees or fast movements detectable by applying pattern recognition approaches.  FIG. 3  is a schematic illustration of a surgical instrument  200  comprising an optical shape sensing device  210  disposed within the surgical instrument  200  and configured to determine a shape and/or position of the surgical instrument  200  relative to a reference, the optical shape sensing device  200  configured to collect information based on its configuration to during a procedure. 
     In an advantageous embodiment the surgical instrument  200  is a flexible instrument including a catheter and/or a guidewire. Such instruments are commonly used by surgeons and the added feature of being able to control functions of the instrument without having to let go of the instrument is an improvement of the safety when operating. 
     As with the garment  100 , the surgical instrument  200  further comprises a connector for connecting to a control computing device  230  generating gesture events based on position information from the optical shape sensing device. Preferably the instrument  200  is connected to a system via a cable  240 . 
     For further improvement of safety is it possible to restrict the system so that the shape sensing  210  can be used for identification purposes: e.g. only when the tracked hand of the interventional cardiologist holds the end of a tracked ablation catheter the ablation procedure can be activated while all other personnel touching the catheter cannot activate it. 
       FIG. 4  schematically illustrates a gesture pattern recognition system  300  comprising a garment  310  to be worn by a human to be monitored, the garment  310  comprising an optical shape sensing device  320  affixed to and running throughout the garment  310  so that shape changes and/or movements of a part of the garment  310  are reflected as shape changes in the optical shape sensing device  320 , wherein the optical shape sensing device  320  are sewed up in, or affixed to, the garment  310  so as to monitor motion, the shape gesture pattern recognition system  300  comprising a processor  330  receiving a signal from the optical shape sensing device  320  and the shape gesture pattern recognition system  300  generating a gesture event based on the signal from the optical shape sensing device  320 . 
     The system is especially suitable for use in a surgical room setting. The optical shape sensing device  320  allows for tracking of movement of the person wearing the garment  310  and the system as a whole may then be used for monitoring if/when the person wishes to issue a command or instruction to a computing device, such as an image display device. The system  300  provides accurate and robust monitoring of movement without limitations of line of sight. 
     A similar system may be defined, with reference  FIG. 3 , wherein a surgical instrument  200  comprising an optical shape sensing device  210  disposed within the surgical instrument  200  and configured to determine a shape and/or position of the surgical instrument  200  relative to a reference, is used. The optical shape sensing  210  device is then connected  240  to a processor  230  in the shape gesture pattern recognition system to collect information based on a signal from the optical shape sensing device  210  relating to the configuration of the instrument  200  to during a procedure, the shape gesture pattern recognition system creating gesture events based on the signal. The person using the system may then issue commands to the pattern recognition system so as to operate further functions in the instrument or an external system such as an image viewing system. 
       FIG. 5  schematically illustrates steps of a method  400  for controlling a gesture pattern recognition system comprising an object with an optical shape sensing device, wherein the shape gesture pattern recognition system is configured to determine a shape and/or position of the object relative to a reference, the method comprising the steps of detecting  410  a gesture pattern of the object, determining  420  if the gesture pattern of the object corresponds to one of a set of recognized gestures, if the gesture pattern is recognized generating a gesture event based on the recognized gesture, and operating  430  a device based on the gesture event. 
     The method may be used in connection with a garment  310  and the optical shape sensing device  320  is then integrated or affixed to the garment  310 , the method may then further comprise detecting gesture patters of the person wearing the garment. 
     Alternatively the method  400  may be used in connection with a surgical instrument  200  comprising an optical shape sensing device  210  disposed within the surgical instrument and configured to determine a shape and/or position of the surgical instrument relative to a reference, the optical shape sensing device configured to collect information based on its configuration to during a procedure. 
     All embodiments described herein may further comprise a further step or device for initiating the gesture control. This could e.g. be a voice recognition system for detecting when an intended command is to be issued by the person wearing the garment or operating the instrument. This allows for improved security as the system or method will not misinterpret movements not related to a command as actual commands. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.