Abstract:
A method and system that recognize a hand gesture using selective illumination that can reliably perform hand gesture recognition by effectively removing an unnecessary image and noise including static disturbance light and dynamic disturbance light are provided. The method of recognizing a hand gesture includes acquiring, by a controller from an imaging device a hand image, which is a recognition target. A static background image and a dynamic background image are removed by the controller from the hand image. The method further includes recognizing, by the controller, a gesture of the hand by extracting a characteristic point from the hand image in which the dynamic background image is removed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of Korean Patent Application No. 10-2012-0157478 filed in the Korean Intellectual Property Office on Dec. 28, 2012, the entire contents of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    (a) Field of the Invention 
         [0003]    The present invention relates to a method and system that recognize a hand gesture using selective illumination that can reliably perform hand gesture recognition by effectively removing an unnecessary image and noise including static disturbance light and dynamic disturbance light. 
         [0004]    (b) Description of the Related Art 
         [0005]    Nowadays, gesture recognition technology that recognizes (or detects) a hand gesture is applied to various fields (e.g., game, vehicle). A system that recognizes a hand gesture includes a hand recognition system that is based on color information, a shape based hand recognition system, and a three-dimensional information based hand recognition system. 
         [0006]    The hand recognition system that is based on color information is a system that searches for colors such as a skin color within stored color information and recognizes a hand based on a size and a shape of the hand. The hand recognition system that is based on color information utilizes a simple recognition algorithm, however, the system is affected by a peripheral environment such as a varying skin colors from person to person and based on light change, and the system may not be used at night where color differentiation cannot be determined. 
         [0007]    The shape based hand recognition system is a system that recognizes a hand, for example, through matching of a template from an existing database (DB) and an image. The shape based hand recognition system may require an increased number of templates, a calculation amount exponentially increases, and the shape based hand recognition system depends on a hand size as well as a hand shape. 
         [0008]    The three-dimensional information based hand recognition system is an active research field and obtains a three-dimensional image using an imaging device, and recognizes a hand based on depth information. The three-dimensional information based hand recognition system can use three-dimensional information, however, the low cost competitive power of the system is affected by disturbance light and the system has an obstacle limitation between a user and an imaging device. 
         [0009]    The hand recognition system described above is affected by an external light source, and a color and a shadow of an object are thus changed causing a probability that a recognition error may occur to increase. 
         [0010]    The above information disclosed in this section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
       SUMMARY 
       [0011]    The present invention provides a method and system that recognize a hand gesture using selective illumination having advantages of reliably recognizing a hand gesture by effectively removing an unnecessary image and noise including static disturbance light and dynamic disturbance light. 
         [0012]    An exemplary embodiment of the present invention provides a method of recognizing a hand gesture that may include: acquiring a hand image, which is a recognition target; removing a static background image from the acquired hand image; removing a dynamic background image from the hand image in which the static background image is removed; and recognizing a gesture of the hand by extracting a characteristic point from the hand image in which the dynamic background image is removed. 
         [0013]    The static background image may be static disturbance light of an external light source, and the dynamic background image may be dynamic disturbance light of an external light source. 
         [0014]    Additionally, the acquiring of a hand image may include acquiring an image of the hand by performing on and off control of a lighting device every predetermined frame unit with a predetermined rule. The predetermined frame unit may be three frame units; the predetermined rule may turn on the lighting device in a first frame of the three frame units and turn off the lighting device in a second frame and a third frame of the three frame units. 
         [0015]    An imaging device that is configured to acquire the image of the hand may be an infrared camera, and the lighting device may be an infrared lighting device. 
         [0016]    Furthermore, the removing of a static background image may include acquiring a static disturbance light removal image by subtracting the second frame from the first frame. The removing of a dynamic background image may include acquiring a dynamic disturbance light image by subtracting the third frame from the second frame and acquiring a dynamic disturbance light removal image by removing the dynamic disturbance light image from the static disturbance light removal image based on the acquired dynamic disturbance light image. 
         [0017]    Another embodiment of the present invention provides a system that recognizes a hand gesture including: an imaging device configured to acquire a hand image, which is a recognition target; a lighting device configured to illuminate light to allow the imaging device to acquire the image of the hand; and a gesture recognition unit configured to recognize the gesture of the hand by removing a static background image and a dynamic background image from the image of the hand that is acquired from the imaging device. 
         [0018]    The gesture recognition unit may be executed by a controller that includes at least one microprocessor operating by a predetermined program or hardware including the microprocessor and the program may be formed with a series of commands that perform the method of recognizing a hand gesture. 
         [0019]    As described above, according to an exemplary embodiment of the present invention, by effectively removing a static background image (e.g., disturbance light) and a dynamic background image (e.g., disturbance light) through an acquired hand gesture by performing on and off control of a lighting device every predetermined frame unit by a predetermined rule, a reliable hand gesture recognition may be performed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is an exemplary schematic diagram of a hand gesture recognition system according to an exemplary embodiment of the present invention; 
           [0021]      FIG. 2  is an exemplary flowchart illustrating a method of recognizing a hand gesture according to an exemplary embodiment of the present invention; 
           [0022]      FIG. 3  is an exemplary diagram illustrating a process of turning on and off a lighting device every predetermined frame with a predetermined rule according to an exemplary embodiment of the present invention; 
           [0023]      FIG. 4  is an exemplary diagram illustrating a process of removing a static background image (disturbance light) according to an exemplary embodiment of the present invention; and 
           [0024]      FIG. 5  is an exemplary diagram illustrating a process of removing a dynamic background image (disturbance light) according to an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0025]    It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, combustion, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g. fuels derived from resources other than petroleum). 
         [0026]    Although exemplary embodiment is described as using a plurality of units to perform the exemplary process, it is understood that the exemplary processes may also be performed by one or plurality of modules. Additionally, it is understood that the term controller refers to a hardware device that includes a memory and a processor. The memory is configured to store the modules and the processor is specifically configured to execute said modules to perform one or more processes which are described further below. 
         [0027]    Furthermore, control logic of the present invention may be embodied as non-transitory computer readable media on a computer readable medium containing executable program instructions executed by a processor, controller or the like. Examples of the computer readable mediums include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards and optical data storage devices. The computer readable recording medium can also be distributed in network coupled computer systems so that the computer readable media is stored and executed in a distributed fashion, e.g., by a telematics server or a Controller Area Network (CAN). 
         [0028]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and the are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
         [0029]    The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. 
         [0030]    Like reference numerals designate like elements throughout the specification. 
         [0031]      FIG. 1  is an exemplary schematic diagram of a hand gesture recognition system according to an exemplary embodiment of the present invention. A hand gesture recognition system according to an exemplary embodiment of the present invention is a system that recognizes a hand gesture using a hand image acquired by an imaging device. 
         [0032]    A hand gesture recognition system according to an exemplary embodiment of the present invention may include an imaging device (e.g., a camera)  100  configured to acquire a hand image  10 , which is a recognition target; a lighting device  150  configured to illuminate the hand  10  to allow the imaging device  100  to acquire an image of the hand  10 ; and a gesture recognition unit  200  configured to generate a signal that controls a control target  300  by recognizing a gesture of the hand  10  by removing a static background image and a dynamic background image from the image of the hand  10  acquired from the imaging device  100 . 
         [0033]    In an exemplary embodiment of the present invention, the imaging device  100  is, for example, an infrared camera configured to effectively remove disturbance light of an external light source (e.g., street lamp, sun light), but it should be understood that the present invention is not limited thereto. In other words, when the imaging device  100  corresponds to the infrared camera, the present invention may be applied thereto. 
         [0034]    In an exemplary embodiment of the present invention, the lighting device  150  may be for example, an infrared lighting device configured to generate lighting appropriate to the infrared camera, but it should be understood that the present invention is not limited thereto. In other words, when the lighting device  150  corresponds to an infrared lighting device, the present invention may be applied thereto. 
         [0035]    The gesture recognition unit  200  may be executed by a controller that includes at least one microprocessor operating by a predetermined program or hardware including the microprocessor. The predetermined program may be formed with a series of commands that perform a method of recognizing a hand gesture according to an exemplary embodiment of the present invention to be described later. 
         [0036]    Hereinafter, a method of recognizing a hand gesture according to an exemplary embodiment of the present invention will be described in detail with reference to the attached drawings. 
         [0037]      FIG. 2  is an exemplary flowchart illustrating a method of recognizing a hand gesture according to an exemplary embodiment of the present invention. As shown in  FIG. 2 , the gesture recognition unit  200  may be configured to acquire an image of the hand  10 , which is a recognition target by operating the imaging device  100  and the lighting device  150  (S 100 ). To acquire an image of the hand  10 , the gesture recognition unit  200  may be configured to turn the lighting device  150  on and off every predetermined frame unit, for example, every 3 frames by a predetermined rule. 
         [0038]    In an exemplary embodiment of the present invention, the predetermined rule is to, for example, turn on the lighting device  150  at the first frame of the three frames and turn off the lighting device  150  at second frame and third frames of the three frames, as shown in  FIG. 3 . 
         [0039]    In  FIG. 3 , the 1 and 4 frames indicate that the lighting device  150  is turned on and the 2, 3, and 5 frames indicate that the lighting device  150  is turned off. Therefore, when the image of the hand  10  is acquired, to acquire only a pure gesture of the hand  10 , the gesture recognition unit  200  may be configured to remove a static background image, more specifically, static disturbance light of an external light source (e.g., street lamp, sun light) (S 200 ). 
         [0040]    To remove the static disturbance light, the gesture recognition unit  200  may be configured to subtract the second frame from a first frame of the hand image, as shown in  FIG. 4 . In other words, the gesture recognition unit  200  may be configured to acquire a hand image in which a static background image (e.g., disturbance light) may be removed by subtracting the second frame from the first frame of the hand image, as shown in  FIG. 4 . 
         [0041]    When the static disturbance light is removed at step S 200 , in the hand image, a dynamic background image, more specifically, dynamic disturbance light of an external light source may not be removed, as shown in  FIG. 5A . Therefore, the gesture recognition unit  200  may be configured to remove the dynamic disturbance light from a hand image in which the static disturbance light is removed (S 300 ). In other words, as shown in  FIG. 5B , the gesture recognition unit  200  may be configured to extract only an image (e.g., pattern) by an influence of dynamic disturbance light by subtracting the third frame from the second frame of the image of the hand  10 . 
         [0042]    When an image by an influence of the dynamic disturbance light is extracted, the gesture recognition unit  200  may be configured to remove dynamic disturbance light remaining in the hand image in which static disturbance light that is shown in  FIG. 5A  is removed using the extracted image by an influence of the dynamic disturbance light. 
         [0043]    A method of removing dynamic disturbance light remaining in the hand image in which static disturbance light that is shown in  FIG. 5A  is removed using the extracted image by an influence of dynamic disturbance light may be performed through a general image removal technology. 
         [0044]    When the image by an influence of dynamic disturbance light is removed from the hand image at step S 300 , the gesture recognition unit  200  may be configured to extract a characteristic point of the hand image using an existing method, recognize the hand gesture based on the extracted characteristic point, and generate a signal that executes a function of the control target  300  based on the recognized hand gesture (S 400 , S 500 , and S 600 ). 
         [0045]    Therefore, according to an exemplary embodiment of the present invention, by effectively removing a static background image (e.g., disturbance light) and a dynamic background image (e.g., disturbance light) through an acquired hand gesture by performing on and off control of a lighting device every predetermined frame unit by a predetermined rule, a reliable hand gesture may be recognized. 
         [0046]    While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. 
       DESCRIPTION OF SYMBOLS 
       [0047]      
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                  10: recognition target (hand) 
                 100: imaging device 
               
               
                   
                 150: lighting device 
                 200: gesture recognition unit 
               
               
                   
                 300: control target