Abstract:
The present invention discloses an optical pointer control system, and a method using in the same system. The system includes: an image display showing a frame having a pointer; a light source generating a light beam; a controller controlling the position of the pointer and including an image sensor receiving the light beam to obtain a image frame having a light spot; and a coordinate transformation processor calculating first coordinates of the light spot in a first coordinate system of the image frame and transferring the first coordinates into second coordinates according to a predetermined second coordinate system; wherein the image display shows the pointer on a corresponding position of the frame according to the second coordinates.

Description:
BACKGROUND OF THE INVENTION 
     Field of Invention 
       [0001]    The present invention relates to an optical pointer control system and an operation method therefor, in particular to such optical pointer control system and operation method wherein the position of a light spot in an image frame obtained by an image sensor is directly transferred into a corresponding position on a displayed image to determine the pointer&#39;s position. 
         [0002]    Many current interactive video game systems provide users with joysticks or remote controllers so that the users can play the games by actions, e.g. to drive a race car, to swing a golf club, etc. Such joystick or remote controller typically includes a gyro, an accelerometer, or an image sensor. In a joystick or remote controller which employs the image sensor, the image sensor senses images and generates information for controlling the movement of a cursor or a pointer on a screen, or for selecting an icon to execute a corresponding function or program, etc. 
         [0003]    In the prior art, the image sensor receives light beams generated from multiple reference points located in the vicinity of a display, wherein each of the reference points includes several light emitting diodes. Accordingly, each image frame captured by the image sensor is an image including multiple light spots. By comparing previous and next image frames wherein complicated calculation is involved such as identifying features in an image frame and calculating a displacement of the features, the joystick controls the cursor and moves it to a desired location. 
         [0004]    U.S. Pat. No. 7,834,848 discloses a prior art technique utilizing images of two references to control a cursor. This prior art is similar to the aforementioned prior art wherein complicated calculation is required, and hence they cannot immediately respond to the instruction of the controller to swiftly move the cursor, and the complicated calculation consumes more power. In another prior art U.S. Pat. No. 5,448,261 which calculates and outputs a relative displacement and moving direction, complicated calculation is also required. 
         [0005]    In view of above, the present invention overcomes the foregoing drawbacks by providing an optical pointer control system and a method, which directly transfer or map the position of a light spot in an image frame captured by the image sensor to a corresponding position on the display to determine the location of a pointer. Thus, no complicated calculation is required so that it can shorten the data processing time to immediately respond to an instruction from the controller, and it also reduces power consumption. 
       SUMMARY OF THE INVENTION 
       [0006]    An objective of the present invention is to provide an optical pointer control system. 
         [0007]    Another objective of the present invention is to provide an operation method of an optical pointer control system. 
         [0008]    To achieve the foregoing objectives, in one aspect, the present invention provides an optical pointer control system, comprising: an image display showing an image including a pointer; a light source generating at least one light beam; a controller controlling a position of the pointer, the controller including an image sensor receiving the light beam to obtain an image frame having a light spot; and a coordinate transformation processor calculating a first coordinate of the light spot in a first coordinate system and transforming the first coordinate into a second coordinate of a predetermined second coordinate system; wherein the image display shows the pointer at a position in the displayed image corresponding to the second coordinate. 
         [0009]    In the foregoing optical pointer control system, the light beam generated by the light source preferably has a specific wavelength. The image sensor preferably includes a filter allowing light with the specific wavelength to pass through. 
         [0010]    In one embodiment of the foregoing optical pointer control system, the first coordinate system is defined by resolution of the image frame outputted from the image sensor. 
         [0011]    In one embodiment of the foregoing optical pointer control system, the second coordinate system is defined by resolution of the image outputted from the image display. 
         [0012]    The foregoing optical pointer control system preferably further comprises a host driving the image display to show the image, wherein the coordinate transformation processor is wholly disposed in the host, or partially disposed in the host and partially disposed in the controller. 
         [0013]    In the foregoing optical pointer control system, the host and the controller may communicate with each other in a wireless way or a wired way. 
         [0014]    In yet another aspect, the present invention provides an operation method of an optical pointer control system, controlling a position of a pointer in a displayed image, comprising: receiving at least one light beam generated from the system to obtain an image frame having a light spot; calculating a first coordinate of the light spot in a first coordinate system and transforming the first coordinate into a second coordinate of a predetermined second coordinate system; and showing the pointer at a position in the displayed image corresponding to the second coordinate. 
         [0015]    The objectives, technical details, features, and effects of the present invention will be better understood with regard to the detailed description of the embodiments below, with reference to the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  shows a schematic diagram illustrating an optical pointer control system of the present invention. 
           [0017]      FIG. 2  shows a schematic diagram illustrating the visual field angles of a controller when receiving the light from a light source. 
           [0018]      FIGS. 3A and 3B  show two image frames captured by the image sensor from the two visual field angles in  FIG. 2 . 
           [0019]      FIG. 4  shows a schematic diagram illustrating an image display on which the movement of the cursor is controlled by the controller in  FIG. 2 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    The present invention is applicable to computers, video players or interactive game systems, such as for moving a pointer on a display of a computer monitor, remote-control of a video player, remote-control of a smart TV, etc. The pointer maybe a cursor or a movable object shown on a display or a monitor. The types of the cursor may be an arrow, an I shape, a cross shape, a hand icon or other controllable position marks represented by any shapes. 
         [0021]      FIG. 1  shows a schematic diagram illustrating an optical pointer control system of the present invention. As shown in this figure, an optical pointer control system  10  substantially comprises a controller  11 , a host  12 , a light source  13  and an image display  14 . The host  12  executes a video game program or a video program, displaying images by the image display  14 . The image display  14  may be an image screen, a projector, a head-mounted display, or other types of display apparatuses. A user operates the controller  11  to interact with the host  12  such that the host  12  executes various actions or instructions such as moving a pointer or a cursor  141  on the image display  14  to the menu at the right side. The light source  13  shown in this embodiment only has a single lighting unit  131 , but in other embodiments, the light source  13  may include multiple lighting units  131 . 
         [0022]    When the controller  11  is operated by the user, the lighting unit  131  of the light source  13  generates an infrared (IR) ray which is imaged in the image sensor  111  of the controller  11 . That is, the image sensor  111  captures an image frame having a light spot formed by the IR ray. The light source  13 /lighting unit  131  preferably has a specific wavelength. In one embodiment, the image sensor  111  includes a filter allowing light with the specific wavelength to pass through. The processor  113  calculates a first coordinate of the light spot in the first coordinate system of the captured image frame, and the first coordinates is transferred into a second coordinate of a predetermined second coordinate system defined by the display  14 , that is, the second coordinate system is defined by the resolution of the image displayed on the image display  14 . The image display  14  shows the cursor  141  on the displayed image  142  according to the second coordinate. In this embodiment, the processor  113  is disposed in the controller  11 ; in other embodiments, it can be disposed in the host  12 . The host  12  includes a transceiver  121 , which communicates with the transceiver  112  of the controller  11  through the radio frequency signals RF 1  and RF 2  (or IR signals) for bidirectional data transmission. In other embodiments, the data transmission can be conducted in a wired way. 
         [0023]      FIG. 2  shows a schematic diagram illustrating the visual field angles of a controller when receiving the light from a light source. As shown in this figure, when the user rightward moves or clockwise rotates the controller  11 , the lighting unit  131  is relatively moved from the right side to the left side of the visual field angle of the image sensor  111 . Referring to  FIG. 3A  and  FIG. 3B , the image sensor  111  captures two image frames according to the different visual field angles at different positions. So, the light spot  331  at the coordinate (x 1 , y 1 ) moves to the coordinate (x 2 , y 2 ) as indicated by the reference number  332 . The coordinates in this coordinate system is obtained according to the resolution of the image sensor  111 . For example, the resolution of the image sensor  111  is 256×256. The coordinate of the pixel where the light spot covers represents the position. The coordinate system of the image sensor  111  is referred to as the first coordinate system herein. To simplify the mapping transformation, in one embodiment, the xy coordinate system in  FIG. 3A  and  FIG. 3B  can be defined as a coordinate system rotating 180 degrees from the normal coordinate system. That is, the coordinate along the horizontal direction increases from the right side to the left side, and the coordinate along the vertical direction increases from the upper side to the lower side. Or alternatively, as shown in the present embodiment, the image sensor  111  is rotated by 180 degrees as it captures images. The present invention has the follow features and advantages: because coordinate of the pixel where the light spot covers represents the position, no complicated calculation is required to identify features in an image, and it is not necessary to compare a feature in a previous image frame with the feature in a next image frame to determine a relative displacement and moving direction. What the present invention generates is an absolute coordinate. In this embodiment, the size of the light spot covers only one pixel. In other embodiments, the light spot may cover multiple pixels; in this case the representative coordinate of the light spot may be the geometric center or the weighted gravity center of the multiple pixels, or the coordinate of any of the pixels. 
         [0024]      FIG. 4  shows a schematic diagram illustrating an image display on which the movement of the cursor is controlled by the controller in  FIG. 2 . Referring to this figure, the cursor  141  in the displayed image  142  on the image display  14  moves from the coordinate (x 1 ′ , y 1 ′) close to the upper left corner to the coordinate (x 2 ′, y 2 ′) as indicated by the reference number  141 ′. The coordinate (x 1 ′, y 1 ′) is directly mapped or transferred from the coordinate (x 1 , y 1 ) in  FIG. 3A . Similarly, the coordinate (x 2 ′, y 2 ′) is directly mapped or transferred from the coordinate (x 2 , y 2 ) in  FIG. 3B . The coordinate system of the image display  14  is referred to as the second coordinate system. A resolution is set to or selected for the image display  14 —1024×768 for example. If the processor  113  knows the resolution of the image display  14  in advance, the coordinates (x 1 , y 1 ) and (x 2 , x 2 ) are directly mapped or transferred to the coordinates (x 1 ′, y 1 ′) and (x 2 ′, x 2 ′), for example by moving average, interpolation, or other methods. If the processor  113  is disposed in the controller  11  and it cannot know the resolution of the image display  14  in advance, it can simply output the coordinates (x 1 , y 1 ) and (x 2 , x 2 ) of the first coordinate system. Then, a processor of the host  12  can transfer the first coordinate system of the image sensor  111  to the second coordinate system of the image display  14 . As such, the coordinates of the light spot captured by the image sensor  111  are mapped to the corresponding coordinates of the second coordinate system in a very easy way, without complicated calculation. In the foregoing description, the processor  113  and the processor in the host  12  can be considered as an overall coordinate transformation processor partially disposed in the controller  11  and partially disposed in the host  12 . That is, the coordinate transformation processor can be completely deposed in the controller  11  (the processor  113  is disposed in the controller  11  and functions as the coordinate transformer), completely deposed in the host (the processor  113  is disposed in the host  12  and functions as the coordinate transformer) or partially disposed in the controller  11  and partially disposed in the host  12  (the process  113  and the processor of the host  12  cowork to function as the coordinate transformer). 
         [0025]    The present invention has been described in considerable detail with reference to certain preferred embodiments thereof. It should be understood that the description is for illustrative purpose, not for limiting the scope of the present invention. Those skilled in this art can readily conceive variations and modifications within the spirit of the present invention. For example, the host  12  may be a game host, a video player or a smart TV. For another example, the processor  113  is shown to be disposed in the controller  11  in the drawing, but it can be disposed in the host  12  or in other parts or locations of the system. The light source  13  can include multiple lighting units  131  that form one light spot together, or form multiple light spots in the image sensor  111 . In the latter case, the coordinate of each of the light spots can be directly transferred to a corresponding coordinate on the image display by the foregoing method, for use to control multiple pointers or cursors. Thus, the present invention should cover all such and other modifications and variations, which should be interpreted to fall within the scope of the following claims and their equivalents.