Apparatus and method for recognizing subject motion using a camera

Abstract

A method for recognizing a subject motion using a camera is provided, in which each of the previous and current image frames received from the camera is split into multiple image blocks, motion blocks are detected among the image blocks based on a difference between previous and current pixel values for each of the image frames, a motion center is detected based on positions of the motion blocks for each image frame, and the subject motion appearing in the previous and current image frames is recognized based on the motion centers of the previous and current image frames.

1 . A method for recognizing a subject motion using a camera, comprising:
 splitting each of previous and current image frames received from the camera into multiple image blocks;   detecting motion blocks from among the image blocks based on a difference between previous and current pixel values, for each of the previous and current image frames;   detecting a motion center based on positions of the motion blocks, for each of the previous and current image frames; and   recognizing a subject motion appearing in the previous and current image frames based on the motion centers of the previous and current image frames.   
     
     
         2 . The method of  claim 1 , further comprising detecting skin color blocks from among multiple image blocks, each of the skin color blocks having a color value falling within a predetermined threshold range;
 wherein the motion blocks are detected from the skin color blocks.   
     
     
         3 . The method of  claim 1 , wherein the detecting of motion blocks comprises:
 detecting motion pixels by comparing a difference between previous and current pixel values with a predetermined pixel threshold, for each of the previous and current image frames; and   detecting the motion blocks by comparing a number of the motion pixels in each of the image blocks with a predetermined block threshold.   
     
     
         4 . The method of  claim 1 , further comprising calculating a distance between the motion centers. 
     
     
         5 . The method of  claim 4 , further comprising calculating a momentum of the subject motion based on the distance between the motion centers and the number of the motion blocks in each of the previous and current image frames. 
     
     
         6 . The method of  claim 5 , further comprising comparing the calculated momentum with a predetermined momentum threshold. 
     
     
         7 . The method of  claim 1 , further comprising estimating a direction of the subject motion based on positions of the motion centers of the previous and current image frames. 
     
     
         8 . The method of  claim 5 , further comprising estimating a strength of the subject motion by comparing the calculated momentum with a predetermined momentum threshold. 
     
     
         9 . The method of  claim 1 , further comprising generating a predetermined event according to the recognized subject motion. 
     
     
         10 . A computer-readable recording medium storing a program causing a processor to execute a process for recognizing a subject motion using a camera, the process comprising:
 splitting each of previous and current image frames received from the camera into multiple image blocks;   detecting motion blocks from among the image blocks based on a difference between previous and current pixel values, for each of the previous and current image frames;   detecting a motion center based on positions of the motion blocks, for each of the previous and current image frames; and   recognizing a subject motion appearing in the previous and current image frames based on the motion centers of the previous and current image frames.   
     
     
         11 . An apparatus for recognizing a subject motion using a camera, comprising:
 a motion block detector for detecting motion blocks in each of previous and current image frames based on a difference between previous and current pixel values, for each of the previous and current image frames received from the camera; and   a momentum and direction determiner for detecting a motion center based on positions of the motion blocks for each of the previous and current image frames, and calculating a distance between the motion centers of the previous and current image frames.   
     
     
         12 . The apparatus of  claim 11 , further comprising a skin color detector for detecting a skin color block from among the image blocks in each of the previous and current image frames, the skin color block having a color value falling within a predetermined threshold range;
 wherein the motion blocks are detected from the skin color block.   
     
     
         13 . The apparatus of  claim 11 , further comprising an event allocator for generating a predetermined event according to the distance between the motion centers.