Human image tracking system, and human image detection and human image tracking methods thereof

A human image tracking method for tracking a human image in a detection area operated by a human image tracking unit connected to an image processing unit and a human image detection unit, the method comprising:

• receiving a current human image position from the human image detection unit and a prior tracking position detected by the human image tracking unit;
• determining whether a distance between the current human image position and the prior tracking position is less than a first predetermined critical value;
• generating a plurality of supposed current human image positions adjacent to the prior tracking position if the distance is less than the first predetermined critical value;
• calculating a plurality of depth distribution similarities between the supposed current human image positions and the prior tracking position;
• calculating a plurality of accurate possibilities of the supposed current human image positions according to the plurality of depth distribution similarities;
• and
• selecting the supposed current human image position corresponding to a maximum accurate possibility as a current tracking position of the human image.

A human image tracking system for detecting and tracking a human image position in a detection area, comprising:

• a depth image sensor configured to detect a depth image data in the detection area;
• and
• a human image tracker comprising:
• an image processing unit connected to the depth image sensor, configured to receive the depth image data and remove a background image of the depth image data for obtaining a foreground image;
• a human image detection unit connected to the image processing unit, configured to receive the foreground image, perform a graph-based segment process on the foreground image to obtain a plurality of graph blocks, determine whether a potential human region exists in the graph blocks according to an area size of each graph block, determine whether the potential human region is a potential human head region according to a similarity between the potential human region and a hemisphere model, determine whether the potential human head region is a real human head region according to an area size of a surrounding region adjacent to the potential human head region, and regard the position of the real human head region as the human image position if the potential human head region is the real human head region;
• and
• a human image tracking unit connected to the human image detection unit, configured to receive a current human image position from the human image detection unit and a prior tracking position detected by the human image tracking unit, generate a plurality of supposed current human image positions adjacent to the prior tracking position according to a distance between the current human image position and the prior tracking position, calculate a plurality of depth distribution similarities between the supposed current human image positions and the prior tracking position, calculate a plurality of accurate possibilities of the supposed current human image positions according to the depth distribution similarities, and select the supposed current human image position corresponding to the maximum accurate possibility as a current tracking position of the human image.