Method and apparatus for detecting an image of a reflective object

Abstract

A method of detecting an image of a reflective object includes the steps of: capturing an exposure image by an image sensor while an LED is ON; down-sampling an exposure image signal from the image sensor to a first digital signal by comparing the level of the first image signal with a first reference level; capturing a dark image by the image sensor while the LED is OFF; down-sampling a second image signal from the image sensor to a second digital signal by comparing the level of the second image signal with a second reference level; computing an image of difference between the exposure image and the dark image by subtracting the second digital signal from the first digital signal; and specifying the image of the reflective object by locating a bright point remaining in the image of difference.

1 - 12 . (canceled) 
     
     
         13 . A computer game program product comprising:
 a computer readable recording medium storing a computer executable game program thereon,   wherein the game program includes:   a first computer readable program code unit operable to cause the computer to generate an image of an imaginary object to be moved by a user in a game and a direction indicator indicating a target direction in which the imaginary object is to be moved by the user in the game;   a second computer readable program code unit operable to cause the computer to generate time-series position data items of a controller of the game, wherein the position data item indicates a position of a representative point of the controller with reference to a predetermined coordinate system; and   a third computer readable program code unit operable to cause the computer to compute a trajectory of the imaginary object such that a direction of movement of the imaginary object is determined using the target direction as a reference based on the time-series position data items.   
     
     
         14 . The computer game program product as recited in  claim 13  wherein the controller has a representative surface for virtually hitting the imaginary object in the game,
 wherein the game program further includes:   a fourth computer readable program code unit operable to cause the computer to generate angle data which indicates an angle of the representative surface of the controller,   wherein the third computer readable program code unit computes the trajectory of the imaginary object such that the direction of movement of the imaginary object is determined using the target direction as the reference based on the position data items and the angle data.   
     
     
         15 . The computer game program product as recited in  claim 13  wherein the position data item is generated based on an image data by an image sensor having an image plane for capturing a series of images of the controller,
 wherein the image plane has a predetermined reference axis that defines a direction of one axis of the coordinate system, and   wherein when a direction of movement of the representative point of the controller is in the direction of the predetermined reference axis, the trajectory is computed such that the imaginary object will go in the direction of the target direction.   
     
     
         16 . The computer game program product as recited in  claim 15  wherein the position data item is generated based on a differential image between an image by the image sensor while a light emitting element is turned on and an image by the image sensor while the light emitting element is turned off. 
     
     
         17 . The computer game program product as recited in  claim 16  wherein the controller has a retroreflective member and the position data item is generated based on an image of the retroreflective member contained in the differential image. 
     
     
         18 . The computer game program product as recited in  claim 14  wherein the position data item and the angle data are generated based on a differential image between an image by an image sensor while a light emitting element is turned on and an image by the image sensor while the light emitting element is turned off. 
     
     
         19 . The computer game program product as recited in  claim 18  wherein the controller has a retroreflective member, and the position data item and the angle data are generated based on an image of the retroreflective member contained in the differential image. 
     
     
         20 . The computer game program product as recited in  claim 13  wherein an obstacle is located between a target indicated by the direction indicator and the imaginary object. 
     
     
         21 . The computer game program product as recited in  claim 14  wherein an obstacle is located between a target indicated by the direction indicator and the imaginary object. 
     
     
         22 . The computer game program product as recited in  claim 13  wherein the game is a golf game. 
     
     
         23 . A game apparatus comprising:
 an image generating unit operable to generate an image of an imaginary object to be moved by a user in a game and a direction indicator indicating a target direction in which the imaginary object is to be moved by the user in the game;   a controller of the game;   a position generating unit operable to generate time-series position data items of said controller, wherein the position data item indicates a position of a representative point of the controller with reference to a predetermined coordinate system; and   a trajectory computing unit operable to compute a trajectory of the imaginary object such that a direction of movement of the imaginary object is determined using the target direction as a reference based on the time-series position data items.   
     
     
         24 . The game apparatus as claimed in  claim 23  wherein the controller has a representative surface for virtually hitting the imaginary object in the game,
 wherein said game apparatus further comprising:   an angle generating unit operable to an angle data which indicates an angle of the representative surface of the controller, and   wherein said trajectory computing unit computes the trajectory such that the direction of movement of the imaginary object is determined using the target direction as the reference based on the time-series position data items and the angle data.   
     
     
         25 . The game apparatus as claimed in  claim 23  further comprising:
 an image sensor,   wherein said position generating unit generates the position data item based on an image data by said image sensor having an image plane for capturing a series of images of the controller,   wherein the image plane has a predetermined reference axis that defines a direction of one axis of the coordinate system, and   wherein when a direction of movement of the representative point of the controller is in the direction of the predetermined reference axis, the trajectory computing unit computes the trajectory such that the imaginary object will go in the direction of the target direction.   
     
     
         26 . The game apparatus as recited in  claim 25  further comprising:
 a light emitting element operable to emit light,   wherein the position generating unit generates the position data item based on a differential image between an image by the image sensor while the light emitting element emits the light and an image by the image sensor while the light emitting element does not emit the light.   
     
     
         27 . The game apparatus as recited in  claim 26  wherein the controller has a retroreflective member, and
 wherein said position generating unit generates the position data item based on an image of the retroreflective member contained in the differential image.   
     
     
         28 . The game apparatus as recited in  claim 24  further comprising:
 an image sensor; and   a light emitting element operable to emit light,   wherein the position generating unit generates the position data item based on a differential image between an image by the image sensor while the light emitting element emits the light and an image by the image sensor while the light emitting element does not emit the light, and   wherein the angle generating unit generates the angle data based on the differential image.   
     
     
         29 . The game apparatus as recited in  claim 28  wherein the controller has a retroreflective member,
 wherein the position generating unit generates the position data item based on an image of the retroreflective member contained in the differential image, and   wherein the angle generating unit generates the angle data based on the image of the retroreflective member contained in the differential image.   
     
     
         30 . The game apparatus as recited in  claim 23  wherein an obstacle is located between a target indicated by the direction indicator and the imaginary object. 
     
     
         31 . The game apparatus as recited in  claim 24  wherein an obstacle is located between a target indicated by the direction indicator and the imaginary object. 
     
     
         32 . The game apparatus as recited in  claim 23  wherein the game is a golf game.