Computerized video gait and motion analysis system and method

A motion analysis system for analyzing the movements of a portion of the body of a subject as it moves along a predetermined path;

• comprising:
• (a) marking means of relatively small size and weight in comparison to the size and weight of the subject and being attachable to the subject so as not to modify or hinder the movement of the subject;
• (b) video recording means for viewing and making a video record of the movements of the subject over a predetermined period of time, and at a recording rate of sixty frames per second, said video recording means being formed to be particularly sensative to said marking means;
• (c) minicomputer means connected to said video recording means and coacting therewith for receiving frame by frame views of the movements of the subject and more particularly the images of said marking means as viewed by said video recording means;
• (d) said minicomputer means including video analysis means for receiving and for sequentially digitizing, into a predetermined array of pixels, each of said views of said movement of said subject and said marker as viewed by said video recording means;
• (e) each said pixel having predetermined horizontal and vertical coordinates with respect to horizontal and vertical reference lines and having a gray level corresponding to the brightness of that part of the image represented by said pixel and particularly the brightness of the image of said marking means as viewed by said video recording means;
• (f) first program means coacting with said minicomputer to effect scanning of each said pixel array and for setting a first threshold of gray level above which said minicomputer will respond and provide a predetermined indication thereof, and for changing said first threshold to a second threshold of gray level when said minicomputer fails to respond to a pixel of at least said first threshold of gray level in a frame at the approximate horizontal and vertical coordinates of a pixel previously responded to by said minicomputer in the previous last scanned frame;
• (g) said first program means coacting with said minicomputer to locate, by x and y type data coordinates, each of said pixels responded to by said minicomputer for each frame so viewed and to record same, and to thereafter automatically and similarly locate each of said pixels having at least the gray level established by said first program for such pixel for all of said frames so viewed and to record same;
• (h) computer means coacting with said minicomputer means for receiving said pixel data coordinates and for combining same into a predetermined data display;
• (i) and data output means coacting with said computer means for providing a visual depiction of said predetermined data display.