Abstract:
Apparatus is disclosed for generating control signals for the manipulation of virtual objects in a computer system according to the gestures and positions of an operator&#39;s hand or other body part. The apparatus includes a glove worn on the hand which includes sensors for detecting the gestures of the hand, as well as hand position sensing means coupled to the glove and to the computer system for detecting the position of the hand with respect to the system. The computer system includes circuitry connected to receive the gesture signals and the hand position signals for generating control signals in response thereto. Typically, the control signals are used to manipulate a graphical representation of the operator&#39;s hand which is displayed on a monitor coupled to the computer system, and the graphical representations of the operator&#39;s hand manipulates virtual objects or tools also displayed by the computer.

Description:
This is a Continuation of application Ser. No. 08/356,123 filed on Dec. 15, 1994 now abandoned; which is a Continuation of application Ser. No. 08/130,813 filed on Oct. 5, 1993, now abandoned; which is a Continuation of application Ser. No. 07/863,396, filed on Mar. 20, 1992, now abandoned; which is a Continuation of application Ser. No. 07/546,333, filed on Jun. 29, 1990, now abandoned; which is a Division of application Ser. No. 07/317,107, filed Feb. 28, 1989, now U.S. Pat. No. 4,988,981; which is a Continuation of application Ser. No. 07/026,930, filed Mar. 17. 1987, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to the field of devices for data entry and manipulation in computers, and relates more particularly to an apparatus and method for entering data into a computer and manipulating virtual objects defined by the computer based on the gestures and positions of the hand, or other parts of the body, of an operator. 
     2. Description of the Prior Art 
     Input devices for computers include such devices as keyboards, digitizers, joysticks, mice, trackballs, and light pens. One function of these input devices is to position, in two dimensions, a cursor on the display screen of a computer. Once the cursor is positioned at a desired location, the computer typically will be instructed to perform an operation. The processes of positioning the cursor and selecting the operation are discrete operations, since separate motions are required to perform each operation. With a mouse, for example, cursor positioning is accomplished by moving the mouse along a surface, while selection of the operation is accomplished by pushing keys located either on the mouse or on a separate keyboard. Mastering the operation of such input devices is often difficult because the hand movements required to operate the devices do not correspond to the visual feedback presented by the display screen of the computer. Furthermore, the operator&#39;s hand(s) must be removed from the keyboard, positioned on the mouse, then returned to the keyboard. 
     Glove input devices also have been used to supply data to computers. U.S. Pat. No. 4,414,537, filed Sep. 15, 1981, by G. Grimes and entitled “Digital Data Entry Glove Interface,” describes one such glove input device. The Grimes patent discloses a glove with sensors for detecting the flexing of finger joints, sensors for detecting contact between various portions of the hand, and sensors for detecting the orientation of the hand. The Grimes device is used to identify static hand positions representing the characters of the alphabet. Furthermore, the glove is designed to differentiate from one another a fixed number of static shapes representing the letters of the alphabet. 
     SUMMARY OF THE INVENTION 
     The present invention provides an apparatus and method for manipulating virtual objects defined by a computer according to the gestures, position, and movement of the hand of an operator. Such manipulation includes positioning a cursor or other representation of the hand of the operator with respect to virtual objects defined by the computer. Operations on those virtual objects may then be carried out according to certain gesture specifying movements of the operator&#39;s hand. The virtual objects themselves may be representations of computer input devices such as a joystick, mouse, pen, keyboard, paintbrush or other devices. More generally, the objects may be tools which themselves act on other virtual objects. For example, a virtual steering wheel may be used to drive a simulation of an automobile, or to provide input to a remote system. 
     The invention includes gesture sensing means coupled to the hand for detecting gesture specifying movements of the hand, such as flexing of the fingers, as well as hand position sensing means for detecting the position of the hand with respect to the display. Signal processing means are provided to receive data from the gesture sensing means and the hand position sensing means to instruct the computer to manipulate the cursor and/or virtual objects according to the movements of the operator&#39;s hand. 
     In one embodiment of the present invention, the gesture sensing means includes a glove assembly with attached sensors that are responsive to the degree of flex of the fingers of the operator&#39;s hand. These flex sensors are mounted on a flexible printed circuit board and are sandwiched between an inner and an outer glove. A decoding circuit for addressing the sensors is also mounted on the flexible printed circuit board, and is electrically coupled to the sensors through the flexible printed circuit board and to the computer via a detachable cable. The hand position sensing means preferably includes one or more ultrasonic transmitters affixed to the glove assembly, a stationary receiver comprising three separate spaced-apart ultrasonic receiving units, and a control circuit that measures the time delay of pulsed ultrasonic signals from the transmitter to the three receivers. The time delay provides a measure of the spatial position of the operator&#39;s hand. The signal processing means includes interface circuitry for coupling the glove to the host computer, for positioning a hand-shaped cursor on the display screen of the computer according to the position of the operator&#39;s hand, for responding to output signals from the flex sensors, and for manipulating virtual objects defined by the computer according to commands represented by the gestures and movement of the operator&#39;s hand. A database within the host computer can be employed to provide constraints, such as inertia, linkage to other objects, etc., for the objects being manipulated. 
     The present invention also comprises a computer data entry and manipulation apparatus and method capable of determining the dynamic gestures of an operator&#39;s hand and the spatial position of the hand. As an input device, the present invention is especially well adapted for use with a pictorial or symbolic programming language having a dynamic cursor which corresponds in shape to the shape of the glove and moves on the screen in response to movement of the glove in space. The present invention provides a basis for use of a symbolic programming language in which the physical gestures of the operator&#39;s hand are used to implement conceptually similar and easily recognizable functions or operations on virtual objects displayed on the display screen of the computer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a preferred embodiment of the computer data entry and manipulation apparatus of the invention; 
     FIG. 2 is a perspective view of the glove assembly  12  shown in FIG. 1, including sensors and and ultrasonic transmitter; 
     FIG. 3 is a circuit schematic of a preferred embodiment of the circuitry on glove  12 ; 
     FIG. 4 is a circuit schematic of an ultrasonic receiver; 
     FIG. 5 is a schematic of an interface circuit used to connect a preferred embodiment of the apparatus of the invention to a host computer; and 
     FIG. 6 is a flowchart of software employed to sense when a virtual object is picked up. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 through 6 of the drawings depict various preferred embodiments of the present invention for purposes of illustration only. One skilled in the art will recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the invention. 
     In FIG. 1, a preferred embodiment of the present invention is illustrated in its intended mode of use, namely as a computer data entry and manipulation apparatus  10 . The apparatus  10  includes a glove assembly  12  electrically coupled via cable  13  to an interface circuit  14  that is, in turn, connected to a port of a host computer  16 . A position sensing receiver assembly  20  consisting of three receivers disposed around the screen  28  is also electrically coupled to the interface circuit  14 . As explained below, the glove assembly  12  contains sensors that detect the flexing of the fingers and other gestures of the hand of an operator, and also contains one or more ultrasonic transducers  17  for transmitting signals to receivers  20  to enable detecting the spatial position of the glove assembly  12  with respect to the computer display. The position sensing receiver assembly  20  includes three ultrasonic receivers  24  located at corners of display  28  facing toward the operator. 
     In operation, the glove assembly  12  is worn on the hand of an operator, and is used to position a cursor  26 , typically a representation of the glove  12 , on the display screen  28  of the computer  16 . A computer generated virtual object is displayed on the screen  28 . The spatial position of the glove assembly  12  is determined by the time delay between transmission of an ultrasonic signal by transducer  17  and the reception of that signal by the receivers  20  of the position sensing receiver assembly  20 . The position and orientation of the fingers is transmitted to the interface circuit  14  by conductive cable  13 , although other well-known techniques such as radio could be employed. Software within the host computer  16  converts the time delay data into orthogonal coordinates, and directs the computer  16  to display the cursor  26  on the display screen  28  accordingly. Thus, movement by the glove assembly  12  in a plane parallel to that of the display screen  28  results in corresponding movement by the cursor  26 . Movement by the glove assembly  12  toward and away from the display screen  28  can be represented by varying the size of the glove representation cursor  26 . 
     Signals from the glove assembly  12  may also enter commands into the computer  16 . As described in detail below, glove assembly  12  contains sensors that respond to the gestures of the operator&#39;s hand. The software receives and interprets gesture indicating data from the sensors of the glove assembly  12  and enters commands into the computer  16  according to the gestures recognized. These commands relate to the manipulation of virtual objects created by the computer  16  and displayed on the display screen  28 . For example, FIG. 6 is a flow chart illustrating software for sensing when an object has been “picked up.” 
     FIG. 2 illustrates the preferred embodiment of the glove assembly  12 . An outer glove, not shown, protects the circuitry attached to the inner glove. The component parts of the glove assembly  12  are bonded or otherwise secured to an inner glove  32 , which is worn on the hand of the operator during operation. In the illustrated embodiment, the sensors and electrical components of the glove assembly are soldered to and electrically interconnected by a flexible printed circuit board  34  (FIG.  2 ), which is itself bonded or otherwise secured to the inner glove  32 . The flexible printed circuit board  34  includes five elongated portions  36  positioned along the back side of the fingers and thumb and extending from a central portion  38  positioned along the back of the hand. Preferably, the inner glove  32  is formed from a material such as stretch knitted nylon which accommodates various sizes of hands and maintains a snug fit during use. The outer glove covers and protects the components of the glove assembly  12 , and improves the aesthetics of the glove assembly. Preferably, the outer glove (not shown) is composed of a light weight and durable material such as cotton. 
     The glove assembly  12  includes flex sensors  40 , each positioned on the back side of the inner glove  32  disposed along the fingers to measure bending. The flex sensors  40  are preferably of the type that will provide a signal that is an analog representation of the degree of bend of each of the fingers and thumb. The flex sensor  40  comprises a flexible tube  42  having interior reflective walls with a light source  44  at one end and a photosensitive detector  46  at the other end. The light source  44  is preferably an infrared light emitting diode, and the photosensitive detector  46  is preferably a phototransistor. The tubing is preferably black glossy soft vinyl. The flexible tube  42  is bonded or otherwise secured to the flexible printed circuit board  34 , with the electrical leads of the light source  44  and the photosensitive detector  46  soldered to appropriate conductive traces of the flexible printed circuit board. The amount of light that impinges on the photosensitive detector  46 , and the corresponding amount of current flowing through the photosensitive detector, is dependent upon the amount of bend of the flexible tube  42 . When the finger is extended the flexible tube  42  is generally straight and a maximum amount of light from the light source  44  impinges on the photosensitive detector  46 . As the finger is flexed progressively, the portion of the tube&#39;s  42  reflective inner wall that is mutually viewed by both the light source  44  and the photosensitive detector  46  decreases, which restricts the amount of light transmitted to the photosensitive detector  46 . Thus, the flex sensors  40  provide an analog signal that indicates the flexing of the operator&#39;s fingers and thumb. A detailed description of typical flex sensors may be found in U.S. Pat. No. 4,542,291, entitled “Optical Flex Sensor,” which is commonly assigned. 
     The glove assembly  12  includes circuitry which is described below in conjunction with FIG.  3 . The decoder chip  48  is soldered to appropriate conductive traces at the central portion area  38  of the flexible printed circuit board  34 . The glove assembly  12  is electrically connected to the interface circuit  14  via a cable  13 , which is preferably a flat ribbon cable that is releasably attached to the flexible printed circuit board  34  by a connector  54 . The cable  13  also supplies power and ground signals to the components of the glove assembly  12 . An optical, radio or other electromagnetic transmitter could also be employed. 
     As mentioned above, the glove assembly  12  includes at least one ultrasonic transducer  17 , for example, a high frequency tweeter, that transmits ultrasonic signals for use in determining the spatial position of the glove assembly. Two transducers are used in some embodiments to provide roll and yaw hand orientation information, and so that at least one will be within “line-of-sight” of the receivers. The ultrasonic transducer(s)  17  is soldered to appropriate conductive traces at the central portion area  38  of the flexible printed circuit board  34 , and is electrically connected to the interface electronics  14  via the cable  13 . Preferably, components  55 , including a transformer and transistor for controlling the ultrasonic transducer  17 , are also contained in the glove assembly  12  and mounted to the flexible printed circuit board  34 . 
     In some embodiments, to counteract possible blocking of the ultrasonic signals by the operator&#39;s hand, a flexible transmission tube  56  is utilized to conduct the ultrasonic signals to a different part of the glove assembly. Transmission tube  56  may extend in any desired direction from the ultrasonic transducer  17  to prevent shadowing. The transmission tube carries the ultrasonic signals transmitted by the ultrasonic transducer  17  and radiates those signals out an open end. The transmission tube ensures that hand gestures do not block the transmission of the ultrasonic signals to the position sensing receiver assembly  18 . 
     In addition to the flex sensors, the glove assembly  12  may also include a hand orientation sensor  70  which provides data indicative of the orientation of the glove assembly relative to the three rotational axis of roll, pitch, and yaw. The orientation sensor  70  can be implemented in various ways, such as a three-axis accelerometer, an array of mercury potentiometers, or a bubble gauge read electro optically. In the preferred embodiment, low frequency magnetic fields like the 3SPACE™ system are employed. This system is available from the Polhemus Navigation Sciences Division of McDonnell Douglas Electronics Co., Essex Junction, Vermont. 
     As an alternative to the use of spatial positioning of the glove assembly  12  for directing the two-dimensional positioning of the screen cursor  26 , wrist motions may be used. For example, the forward and back flexing of the wrist can indicate vertical positioning of the screen cursor  26 , while left and right flexing of the wrist can indicate horizontal positioning of the screen cursor. To achieve this additional flex sensors may be secured to the inner glove at locations surrounding the wrist-joint. 
     FIG. 3 is a schematic illustrating the circuitry present on the glove according to a preferred embodiment of the invention. The circuitry shown includes a series of light-emitting diodes LX 0 ,LY 0  . . . LX 7 , LY 7  together with a series of solid state photodetectors PX 0 ,PY 0  . . . PX 7 ,PY 7 . As explained above, these light-emitting and sensing devices are employed in the bend sensors disposed on the glove, and provide direct readings of finger bending. The circuitry shown also includes a dual 2-line to 4-line demultiplexer U 1 , typically a 74LS156 integrated circuit. This circuit receives signals from the host computer and sequentially turns on the appropriate light source by connecting one of terminals L 0 -L 7  to ground. The output signal from the photodetector is supplied on one of lines J 1 . 5 , J 1 . 9  to the detector circuitry, which is described below. 
     The ultrasonic transmitter XT 1  is controlled by a transistor Q 1 , preferably a type 2N2222 under control of signals supplied on line J 1 . 4 , which are supplied through a 10:1 step-up transformer T 1 . When the transmitter is turned on, a pulse of high frequency (about 40 kHz) sound is broadcast. The sound is received by the ultrasonic receivers  20  disposed around the monitor. Preferably, the ultrasonic transmitter XT 1  is an ultrasonic piezoelectric ceramic tweeter, while the ultrasonic receiver comprises an ultrasonic piezoelectric ceramic microphone. Both such devices are commercially available from Panasonic. The time delay between the transmission of the signal by transmitter XT 1  and its reception by the receivers  20  is indicative of the distance between the transmitter and each of the receivers. (Ultrasonic sound travels at about 330 meters per second.) The three distances measured between the glove and the three receivers define the position of the hand with respect to the receivers. 
     If PA is the distance from the ultrasonic transmitter to receiver A, PB the distance to receiver B and PC the distance to receiver C, and if AB and AC equal the distance between A and B, and A and C, respectively, then                    x   =         PA2   -   PB2   +   AB2       2      AB       ≅       K   1          (     PA   -   PB   +       1   /   2        AB       )                     y   =         PC2   -   PA2   +     A                 C2         2      A                 C       ≅       K   2          (     PC   -   PA   +       1   /   2        A                 C       )                           z   =           PA   2     -     X   2     -     Y   2         ≅       K   3          (     PA   +   PB   +   PC     )                                      
     where x, y and z are the distances from the origin of a rectangular coordinate system. Because the position equations require squares and square roots, the approximations are easier to calculate, requiring only addition, subtraction and scaling by constants K 1 , K 2 , and K 3 . 
     The measurement of this distance is initiated by the host computer sending a control byte to select a receiver  20  to generate a short duration high frequency pulse by triggering U 4  in FIG.  5 . The host then measures the time, using a counter internal to the computer, required for the reception of an ultrasonic signal. When received, this signal generates an interrupt by U 32 . The time between sending the control byte and the interrupt is proportional to the distance for the receiver  20  selected. By polling all three receivers sequentially at a sufficiently high frequency, the position of the glove with respect to the receivers may be readily determined. 
     FIG. 4 is a schematic illustrating the ultrasonic receivers and the interconnections among them. As shown in the upper portion of FIG. 4, each receiver includes an ultrasonic receiver XR 1  for receiving the signals, together with a two-stage amplifier comprising two transistors Q 1  and Q 2 , preferably type 2N2222, which amplify the received signal and supply it on line RCV. The two-stage amplifiers are employed immediately next to the receiver transducer to minimize noise. Each of the receivers is disabled during and shortly after the transmission pulse by Q 1  to prevent false detections. Preferably, the transmission lasts about 0.5 msec. (about 20 cycles of a 40 kHz signal), while the post transmission blanking lasts for about 0.2 msec. 
     FIG. 5 is a detailed schematic of the interface circuitry which couples both the glove and ultrasonic receivers to the host computer. The interface circuitry includes provision for two gloves so the operator may wear one on each hand, if necessary. In a preferred embodiment the interface circuitry adapts between a user port, for example, on a Commodore 64 computer, having the characteristics shown in FIG.  5 . The circuitry shown includes three jacks, J 1 , J 2 , and J 3 . The output signals from glove # 1  shown in FIG. 3 are connected to jack J 1 , while those from an optional glove # 2  are connected into jack J 2 . The output terminals of the three receiver  20  amplifiers are connected into jack J 3 . The three jacks are connected to the input terminals of a dual four-channel analog multiplexer U 2 , preferably a type 4052 integrated circuit. This integrated circuit functions as a two pole four-throw switch and routes one of the channels from glove # 1 , glove # 2 , or the ultrasonic receivers to the detector circuitry. The channel routed to the detector circuitry is under control of terminals M 1  and M 2  from the user port. 
     The jacks J 1 , J 2 , and J 3  are coupled to terminals X 0  . . . X 3 , Y 0  . . . Y 3  of switch U 2 . The determination of which of these input terminals is coupled to the output terminals X and Y is made under the control of input signals M 1  and M 2  connected to terminals A and B of switch U 2 . M 1  and M 2  are signals supplied by the user port from the host computer. Under control of M 1  and M 2 , one of the Y input signals will be supplied to the Y output terminal or one of the X input signals supplied to the X output terminal. The Y terminal provides bend sensor information, while the X terminal provides information from one of the ultrasonic receivers. 
     Assuming that the Y terminal of U 2  has been selected, the host computer pulls node /C low to discharge capacitor C 13 . Once node /C is released, the bend sensor current supplied at output terminal Y will begin charging capacitor C 13 . Comparator U 31  compares a reference voltage Vr with the potential on the Y output terminal. When the Y output terminal exceeds the reference voltage, which is approximately ⅔ of 5 volts, the output of comparator U 31  goes to ground potential. This drop in potential on node /F is interpreted by the host computer as an interrupt signal. The delay between pulling node /C low and node /F going low is indicative of the extent of bending of the bend sensor interrogated. 
     The X output terminal from switch U 2  provides information with respect to the time delay between transmission of the ultrasonic signal and its reception, and thereby information relating to the distance between the transmitter and the selected receiver. The ultrasonic pulse is generated by the circuitry in the lower portion of FIG. 5 explained below. In the similar manner to that described above, the output signal on terminal X of switch U 2  is compared by comparator U 32  to a reference voltage. Because the output signal on node X is an AC signal, diode D 3  prevents it from becoming too negative. Transistor Q 1  functions to turn off the detector circuit when node T is held high, while a pulse is being transmitted. Capacitor C 8  and resistor R 15  provide a time delay to blank operation of the detector immediately after pulse transmission to prevent interpretation of electric noise as indicative of the transmitter-receiver separation. The potentiometer R 4  allows adjusting the reference potential to trim to allow for manufacturing tolerances. Once output signal X exceeds the reference voltage, the output node of comparator U 32  is pulled low to create an interrupt signal on line /F, which is supplied to the host computer. 
     The circuitry of the remaining portion of FIG. 5 is used to generate the ultrasonic pulse for transmission by the transducer mounted on the glove. The heart of this circuit is a dual timer U 4 , typically a type 556 integrated circuit. Half the timer determines the transmission duration, typically about 0.5 msec., while the other half determines the transmission frequency, typically 40 kHz. Diodes D 5 -D 8  AND the resulting pulse train with the transmit enable control bits X 1  and X 2  and are applied to comparators U 33  and U 34 . These comparators drive a 1:10 step-up pulse transformer T 1  through Q 1  shown in FIG.  3 . Potentiometer R 17  is employed to set the frequency and potentiometer R 19  controls the number of pulses transmitted. B 1  and B 2  are connected to jacks J 1  and J 2  and thereby provide the pulse train to the base of transistor Q 1  in FIG.  10 . 
     FIG. 6 is a flow chart which illustrates one technique by which the data entry and manipulation application of this invention may operate. Assume that an object is displayed on the screen and represented within the memory of the computer system by virtue of a table in a database indicative of the exterior appearance of the object. As the user of the system moves his hand in space, the position and orientation of the glove are continuously detected by the computer system as shown by block  140 . After each determination of the position of the glove, the display  28  is updated to reflect the new glove position and orientation, as indicated by block  142 . After the display is updated, the position and orientation of the glove are checked to determine whether an object has been “picked up” on the screen. This may be achieved using any desired well known algorithm, for example, by determining whether at least two points on the representation of the glove are coincident with at least two points on the object. The step is shown by block  144 . If no coincidence occurs between the glove representation and object, control is returned to block  140  and the position of the glove is again read. If coincidence between the object and glove are found, control passes to block  146  and the object is displayed in its new position. Once the object has been redisplayed, control returns to block  140  so that the position of the glove may be again read. 
     The foregoing is a description of a preferred embodiment of the invention. It should be understood that specific details, such as component types, have been provided to explain the construction of the invention. The scope of the invention may be determined from the appended claims.