Moving object tracking method using occlusion detection of the tracked object, and image processing apparatus

A moving object tracking method for tracking a moving object by setting a tracking area corresponding to the moving object appearing in an image, setting a plurality of feature points in the tracking area, and tracking the plurality of feature points, comprising steps of:

• tracking each of the plurality of feature points from the preceding frame to the present frame;
• specifying the position of the tracking area in the present frame by estimating the motion of the tracking area on the basis of the tracking result of each of the feature points,
• detecting the occurrence of an occlusion of the moving object overlapping with an other object, and
• calculating an occlusion value indicating the possibility of the occurrence of the occlusion of the moving object by utilizing a change of a number of feature points being successfully tracked, wherein
• said moving object tracking method calculates a reliability indicator indicating a probability that a feature point has been tracked in the moving object for each of the feature points;
• calculates the motion of the tracking area using the reliability indicator of each feature point and the occlusion value;
• setting a plurality of groups of feature points among the feature points based on the respective reliability indicators;
• and
• calculating the occlusion value based on a change of the number of the feature points being successfully tracked among different groups of the plurality of groups of feature points.

A computer readable medium encoded with a program for making a computer execute a moving object tracking method for tracking a moving object by setting a tracking area corresponding to the moving object appearing in an image, by setting a plurality of feature points in the tracking area, and by tracking the plurality of feature points, said moving object tracking method comprising the steps of:

• tracking each of the plurality of feature points from the preceding frame to the present frame;
• specifying the position of the tracking area in the present frame by estimating the motion of the tracking area based the tracking result of each of the feature points;
• detecting the occurrence of an occlusion of the moving object overlapping with an other object;
• and
• calculating an occlusion value indicating the possibility of the occurrence of the occlusion of the moving object by utilizing a change of a number of feature points being successfully tracked, wherein
• said moving object tracking method calculates a reliability indicator indicating a probability that a feature point has been tracked in the moving object for each of the feature points,
• calculates the motion of the tracking area using the reliability indicator for each feature point and the occlusion value;
• setting a plurality of groups of feature points among the feature points based on the respective reliability indicators;
• and
• calculating the occlusion value based on a change of the number of the feature points being successfully tracked among different groups of the plurality of groups of feature points.

A monitoring apparatus comprising:

• an image processing unit configure to receive a picture signal output from imaging means to track a moving object appearing in an image indicated by the picture signal;
• and
• a security processing unit configured to monitor the moving object utilizing a tracking result output by the image processing unit, wherein
• said image processing unit sets a tracking area in an image corresponding to the moving object, and sets a plurality of feature points in the tracking area, and further tracks the plurality of feature points, and
• said image processing unit includes a tracking processing unit configured to track each of the plurality of feature points from the preceding frame to the present frame, a motion calculation processing unit configured to estimate the motion of the tracking area on the basis of a tracking result of each of the feature points to specify the position of the tracking area in the present frame, and
• an occlusion detecting unit configured to detect the occurrence of an occlusion of the moving object overlapping with an other object, said occlusion detecting unit calculates an occlusion value indicating the possibility of the occurrence of the occlusion of the moving object by utilizing a change of a number of feature points being successfully tracked, wherein
• said tracking processing unit calculates a reliability indicator indicating a probability that a feature point has been tracked in the moving object for each of the feature points, and
• said motion calculation processing unit calculates the motion of the tracking area using the reliability indicator for each of the feature points and the occlusion value;
• wherein
• said occlusion detecting unit sets a plurality of groups of feature points among the feature points based on the respective reliability indicators;
• and
• said occlusion detecting unit calculates the occlusion value based on a change of the number of the feature points being successfully tracked among different groups of the plurality of groups of feature points.

A game apparatus comprising:

• an image processing unit configured to track a moving object appearing in an image encoded in an input picture signal;
• a user's operation unit configured to accept an operation of a user;
• and
• a game processing unit configured to execute a game program on the basis of a tracking result output by the image processing unit and an operation signal from the user's operation unit, wherein
• said image processing unit sets a tracking area in an image corresponding to the moving object, and sets a plurality of feature points in the tracking area to track the plurality of feature points, and
• said image processing unit includes a tracking processing unit configured to track each of the plurality of feature points from the preceding frame to the present frame, a motion calculation processing unit configured to estimate the motion of the tracking area based on the tracking result of each of the feature points to specify the position of the tracking area in the present frame, and
• an occlusion detecting unit configured to detect the occurrence of an occlusion of the moving object overlapping with an other object, said occlusion detecting unit calculates an occlusion value indicating the possibility of the occurrence of the occlusion of the moving object by utilizing a change of a number of feature points being successfully tracked, wherein
• said tracking processing unit calculates a reliability indicator indicating a probability that a feature point has been tracked in the moving object for each of the feature points, and
• said motion calculation processing unit calculates the motion of the tracking area using the reliability indicator for each of the feature points and the occlusion value;
• wherein
• said occlusion detecting unit sets a plurality of groups of feature points among the feature points based on the respective reliability indicators;
• and
• said occlusion detecting unit calculates the occlusion value based on a change of the number of the feature points being successfully tracked among different groups of the plurality of groups of feature points.