Abstract:
An input apparatus for a multi-layer on-screen display and a method of generating an input signal for a multi-layer on-screen display. The input apparatus includes: an acceleration sensing unit for sensing an acceleration of a motion of the input apparatus; a processing unit for obtaining information including a motion depth and a motion pattern of the input apparatus using the sensed acceleration and determining a layer to be activated from the information; and a transmitter for generating a signal including the determined layer and outputting the signal to the multi-layer OSD.

Description:
BACKGROUND OF THE INVENTION 
     This application claims the priority from Korean Patent Application No. 2003-84725,filed on Nov. 26, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     1. Field of the Invention 
     The present invention relates to an input apparatus for a multi-layer on-screen display and a method of generating an input signal for the same. 
     2. Description of the Related Art 
     An on-screen display (OSD) is a program used to select menus in TVs or monitors. A conventional OSD used in display devices such as TVs and monitors is configured with one layer. In the one-layer OSD, a menu selection is realized using a hierarchy method of searching from an upper menu to a lower menu in the lower menu selection. That is, to select a lower menu, an upper menu is first selected and then the lower menu is selected step by step, and to select another lower menu, an upper menu is first selected again and then the lower menu is selected step by step. The menu selection method is not so inconvenient for TVs or monitors in which a number of menus is small. However, in TVs or monitors in which a plurality of menus are required due to various functions, the one-layer OSD is inconvenient to users. 
     The problem can be solved using a multi-layer OSD. Since the multi-layer OSD includes multiple layers each including a plurality of menus, a menu can be selected while moving among the layers. The multi-layer OSD can be utilized as a menu selection method of digital TVs requiring various functional menus. 
     As an input apparatus for the multi-layer OSD, there is a conventional remote control device using buttons. However, the conventional remote control device requires a plurality of additional buttons for each layer. Therefore, there is a need for an input apparatus for inputting signals on the basis of a user&#39;s input operation and an input signal generating method for the same. 
     SUMMARY OF THE INVENTION 
     The present invention provides an input apparatus for generating a signal input to a multi-layer OSD by sensing acceleration information according to a signal input operation by a user and extracting position information of a 3-dimensional space using the sensed acceleration information and an input signal generating method for the same. 
     According to an exemplary embodiment of the present invention, there is provided an input apparatus for a multi-layer OSD, the apparatus comprising: an acceleration sensing unit for sensing an acceleration of a motion of the input apparatus; a processing unit for obtaining information including a motion depth and a motion pattern of the input apparatus using the sensed acceleration and determining a layer to be activated from the information; and a transmitter for generating a signal including the determined layer and outputting the signal to the multi-layer OSD. 
     According to another exemplary embodiment of the present invention, there is provided a method of generating an input signal for a multi-layer OSD using a predetermined input apparatus, the method comprising: sensing an acceleration of a motion of the input apparatus; obtaining information including a motion depth and a motion pattern of the input apparatus using the sensed acceleration; determining a layer to be activated from the information; and outputting the determined layer to the multi-layer OSD. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: 
         FIG. 1  illustrates an exterior view of an input apparatus of a multi-layer OSD according to an exemplary embodiment of the present invention; 
         FIG. 2  is a schematic block diagram of the inside of a body part of  FIG. 1 ; 
         FIG. 3  is a block diagram of a processing unit of  FIG. 2 ; 
         FIG. 4  illustrates layer increasing/decreasing in response to a layer selection signal according to an embodiment of the present invention; 
         FIG. 5A  illustrates Y-axial acceleration versus time in a navigation frame when both of the acceleration and angular velocity are measured in a body frame; 
         FIG. 5B  illustrates Y-axial acceleration versus time in a navigation frame when the acceleration is measured in a body frame according to an exemplary embodiment of the present invention; 
         FIG. 6A  illustrates a low pass filtering result of an acceleration signal of  FIG. 5B  for removing high frequency components from the acceleration signal; 
         FIG. 6B  illustrates a signal output from an operation signal extractor; 
         FIG. 6C  illustrates a signal which is an integral of an absolute value of the signal of  FIG. 6B ; 
         FIG. 6D  illustrates depth information which is an integral of the signal of  FIG. 6C ; and 
         FIG. 6E  illustrates a layer selection signal output according to the depth information of  FIG. 6D . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, the present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. 
       FIG. 1  illustrates an exterior view of an input apparatus of a multi-layer OSD according to an exemplary embodiment of the present invention. Referring to  FIG. 1 , an input apparatus includes a body part  10  and a button  11  attached to a portion of the body part  10 . A signal is input by a user pushing the button  11  and moving the body part  10  backward/forward. Though the input apparatus of a multi-layer OSD shown in  FIG. 1  is an independent apparatus, it can be realized by being embedded into a conventional remote control device. 
       FIG. 2  is a schematic block diagram of the inside of the body part  10  of  FIG. 1 . Referring  FIG. 2 , the body part  10  includes an acceleration sensing unit  20 , a processing unit  21 , and a transmitter  22 . The transmitter  22  transmits input signals via an antenna  23  in a wireless environment. Also, the transmitter  22  can transmit input signals via a wired interface. 
     The acceleration sensing unit  20  senses an acceleration of a motion when a user operates an input apparatus for inputting a signal and includes a 3-axial acceleration sensor. When the user lets a front part of the input apparatus face an OSD and moves the input apparatus forward/backward, the 3-axial acceleration sensor senses the motion of the body part  10  and outputs an acceleration signal. 
     In general, in order to estimate a position and an orientation of a moving object in a 3-dimensional space without an external reference, a 3-dimensional inertial navigation system (INS) based on 3-axial acceleration information and 3-axial angular velocity information is used. An orientation of the INS can be obtained by solving integral equations of angular velocity measured by a gyroscope, which is an angular velocity sensor. The position can be obtained by removing a gravity component from the acceleration measured by the acceleration sensor in consideration of the orientation of the INS and calculating a double integral over time. Since the orientation of the INS includes an error proportional to time for a measurement error of the angular velocity due to a measurement error of the gyroscope, the acceleration in which the gravity component has been removed also includes an error proportional to time of a measurement error of the angular velocity. Therefore, the position includes an error proportional to the square of time for a measurement error of the acceleration and an error proportional to the cube of time for a measurement error of the angular velocity. Since the errors rapidly increase in proportion to time, it is very difficult to calculate a position using an inertial sensor for a long time period. Accordingly, in the present invention, only an acceleration sensor relatively less sensitive to errors is used. 
     The processing unit  21  calculates a position of the input apparatus from an acceleration value output from the acceleration sensing unit  20 . For this, the processing unit  21  converts an acceleration value output from the acceleration sensing unit  20  into a digital acceleration value, performs a proper operation on the digital acceleration value, and outputs a layer selection signal to be input to the multi-layer OSD. 
     The transmitter  22  includes a wireless communication module for converting the layer selection signal into a proper wireless signal such as an infrared signal and transmitting the wireless signal via the antenna  23 . Also, the transmitter  22  can include a wired communication module. 
       FIG. 3  is a block diagram of the processing unit  21  of  FIG. 2 . Referring to  FIG. 3 , the processing unit  21  includes an analog-to-digital converter (ADC)  30 , a frame transformer  31 , an operation signal extractor  32 , a depth information generator  33 , a motion pattern recognizer  34 , and a layer determinator  35 . 
     The ADC  30  converters the acceleration value output from the acceleration sensing unit  20  into the digital acceleration value. The ADC  30  can further include a low pass filter to reduce noise of the acceleration signal output from the acceleration sensing unit  20 . Here, the noise is a high frequency component inherited in the acceleration sensing unit  20  or mixed in the acceleration signal from neighbor elements. 
     The frame transformer  31  performs frame transformation on the acceleration signal output from the ADC  30 . Here, the frame transformation means that the acceleration signal sensed by the acceleration sensing unit  20  in a body frame, which takes a point on the input apparatus as an origin, is transformed into an acceleration signal in a navigation frame, which takes a point in a space where the input apparatus is placed as an origin. To perform the frame transform, the frame transformer  31  calculates an orientation of the input apparatus from the acceleration signal. The orientation is obtained by calculating parameters indicating the orientation of the input apparatus in the navigation frame from the acceleration information according to a well-known INS theory. The parameters may be exemplified by Euler angles, that is, a yaw angle ψ for a rotation around the z-axis of the input apparatus, a pitch angle θ for a rotation around the y-axis after the z-axis rotation, and a roll angle φ for a rotation around the x-axis after the y-axis rotation. The pitch angle and roll angle are calculated as shown in Equation 1. 
     
       
         
           
             
               
                 
                   
                     
                       
                         ϕ 
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     Here, A bx , A by , A bz  are acceleration signals in the body frame output from the acceleration sensor attached to the input apparatus, and g is acceleration of gravity. 
     The yaw angle is rarely varied since a user mainly moves the input apparatus forward and backward. Accordingly, it can be acceptable that ψ=0. 
     The frame transformer  31  obtains acceleration in the navigation frame using the Euler angles obtained from Equation 1 and ψ=0. In the present exemplary embodiment, an input is performed by moving the input apparatus forward and backward, and the forward and backward movement is performed along the y-axis of the navigation frame. Therefore, only an acceleration component A ny  of the y-axis direction of the acceleration signal in the navigation frame is considered. A ny  is obtained from the Euler angles as shown in Equation 2.
 
 A   ny =cos θ sin ψ A   bx +(cos φ cos ψ+sin φ sin θ sin ψ) A   by +(−sin φ cos ψ+Cos φ sin θ sin ψ) A   bx    (2)
 
     When ψ=0, Equation 2 is simplified to Equation 3.
 
 A   ny =cos φ A   by −sin φ A   bz    (3)
 
     The frame transformer  31  can further include a low pass filter to remove a high frequency component from the A ny  value. 
     The operation signal extractor  32  extracts a user&#39;s operation signal by comparing A ny  to a predetermined threshold value to remove a noise signal generated by the user&#39;s hand trembles or etc., even if the user does not move the input apparatus. That is, if an absolute value of A ny  is smaller than the threshold value C th1 , it is regarded that the user does not operate the input apparatus, and if the absolute value of A ny  is larger than the threshold value C th1 , it is regarded that the user operates the input apparatus. Also, to obtain position information later, A ny  is changed as shown in Equation 4. 
     
       
         
           
             
               
                 
                   
                     
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     Here, Â ny  is an output of the operation signal extractor  32 , and C th1  is a constant larger than 0. Provided that C th1  can be larger than a value output from the acceleration sensor, which is output by the user&#39;s hand trembles not by a user&#39;s intended operation and by drift of the acceleration sensor. 
     In detail, if an absolute value of A ny  is smaller than C th1 , it is determined that there is no user&#39;s intended operation. Accordingly, it is regarded that there is no motion. Also, during a forward or backward operation, if A ny  is larger than C th1  or smaller than −C th1 , it is determined that a user moves the input apparatus intentionally. Then, C th1  is added to or subtracted from a measured value. 
     The depth information generator  33  and the motion pattern recognizer  34  extract motion information such as depth of the motion and whether forward or backward motion occurs, respectively. That is, information of which direction and how far the input apparatus is moved is extracted. The depth information generator  33  generates depth information using Â ny . Here, the depth information is a value indicating how far the input apparatus is moved from a current position. The depth information {circumflex over (P)} ny  is obtained by integrating {circumflex over (V)} ny , and {circumflex over (V)} ny  is obtained by integrating an absolute value of Â ny . 
     The motion pattern recognizer  34  classifies patterns of stop, forward, and backward from a value and sign of Â ny . A previous pattern is maintained until another pattern is sensed. If by Â ny =0 during a first time period T 1 , the operation is recognized as a stop, if Â ny  is changed from 0 to Â ny &gt;0 during a second time period T 2 , the operation is recognized as forward. If Â ny  is changed from 0 to Â ny &lt;0 during the second time period T 2 , the operation is recognized as backward. Here, T 1  and T 2  may vary depending on application or systems. 
     The layer determinator  35  determines a layer according to the value {circumflex over (P)} ny  obtained by the depth information generator  33  and the result obtained by the motion pattern recognizer  34  and outputs the determined layer as a layer select signal. If the value {circumflex over (P)} ny  is larger than a predetermined threshold value C th2  (C th2  is a constant larger than 0) and the result obtained by the motion pattern recognizer  34  is the forward operation, the layer determinator  35  increases a present layer by one and resets values of {circumflex over (V)} ny  and {circumflex over (P)} ny  to 0. 
     If the value {circumflex over (P)} ny  is larger than the predetermined threshold value C th2  and the result obtained by the motion pattern recognizer  34  is the backward operation, the layer determinator  35  decreases the present layer by one and resets values of {circumflex over (V)} ny  and {circumflex over (P)} ny  to 0. The reset is to initialize the values of {circumflex over (V)} ny  and {circumflex over (P)} ny  in a currently determined layer. If the value {circumflex over (P)} ny  is not larger than the predetermined threshold value C th2 , the layer determinator  35  maintains a current layer. Here, the predetermined threshold value C th2  is a value for determining a motion of the input apparatus to be an intended input by the user only when the input apparatus is moved more than a predetermined distance. C th2  can be determined by experiments. 
     The layer determinator  35  outputs a layer select signal according to results output from the depth information generator  33  and the motion pattern recognizer  34 . The layer select signal includes a layer to be activated of total layers. For example, if a second layer is active now and it is determined that a forward operation occurs, a signal activating a third layer becomes the layer select signal. Likewise, if a second layer is active now and it is determined that a backward operation occurs, a signal activating a first layer becomes the layer select signal. 
     If a currently activated layer is the uppermost layer and it is determined that a forward operation is ensued, the layer determinator  35  maintains the activated uppermost layer. In another exemplary embodiment, if a currently activated layer is the uppermost layer and it is determined that a forward operation is ensued, the layer determinator  35  can outputs the layer select signal so as to activate the lowest layer in a circulating pattern. 
     On the contrary, if a currently activated layer is the lowest layer and it is determined that a backward operation is ensued, the layer determinator  35  maintains the activated lowest layer. In another exemplary embodiment, if a currently activated layer is the lowest layer and it is determined that a backward operation is ensued, the layer determinator  35  can outputs the layer select signal so as to activate the uppermost layer in a circulating pattern. 
       FIG. 4  illustrates layer increasing/decreasing in response to a layer selection signal according to an exemplary embodiment of the present invention. Referring to  FIG. 4 , an active layer increases or decreases according to a forward/backward operation of an input apparatus. Also, if layer  4  is activated now and the forward operation occurs, the layer determinator  35  maintains layer  4  active. On the contrary, if layer  1  is active now and the backward operation occurs, the layer determinator  35  maintains layer  1  active. 
       FIGS. 5 and 6  illustrate how layers are changed when the input apparatus is moved. The number of layers is  4 , and an initial layer is layer  1 . 
     Referring to  FIGS. 5 and 6 , movement between layers is set so as to forward from a stop status set as the layer  1 , pass through layer  2  and layer  3 , and reach layer  4 , and to backward from layer  4 , pass through layer  3  and layer  2 , and finish the operation at layer  1 . 
       FIG. 5A  illustrates Y-axial acceleration versus time in a navigation frame when both of the acceleration and angular velocity are measured in a body frame.  FIG. 5B  illustrates Y-axial acceleration versus time in the navigation frame when the acceleration is measured in the body frame according to an exemplary embodiment of the present invention. Comparing  FIG. 5A  and  FIG. 5B , the acceleration is unstable since the acceleration is continuously increasing with time in  FIG. 5A , however, a moving status and a stop status can be discriminated in  FIG. 5B . 
       FIG. 6A  illustrates a low pass filtering result of an acceleration signal of  FIG. 5B  for removing a high frequency component from the acceleration signal.  FIG. 6B  illustrates a signal output from the operation signal extractor  32 .  FIG. 6C  illustrates a signal which is an integral of an absolute value of the signal of  FIG. 6B .  FIG. 6D  illustrates depth information that is an integral of the signal of  FIG. 6C . 
       FIG. 6E  illustrates a layer selection signal output according to the depth information of  FIG. 6D . Referring to  FIG. 6E , the layer selection signal is output with some delay compared with the depth information of  FIG. 6D . Also, referring to  FIG. 6B , if a forward operation signal is generated between 8 seconds and 10 seconds when layer  4  is active, the layer selection signal still activates layer  4 . Likewise, if a backward operation signal is generated between 14 seconds and 16 seconds when layer  1  is active, the layer selection signal still activates layer  1 . 
     As described above, in realizing an input apparatus for a multi-layer OSD, the input apparatus can be realized using only a 3-axial acceleration sensor. Accordingly, the size and consumption power of the apparatus can be reduced and expenses also can be cut down. Since complex computation, such as rotating angle calculation according to angular velocity sensing, does not have to be performed, a high performance microprocessor is not necessary. 
     In an aspect of a user interface, since a layer can be selected using only forward/backward operations, the input apparatus can be easily handled. 
     While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.