Motion analysis system employing various operating modes

• US 4,813,436 A
• Filed: 07/30/1987
• Issued: 03/21/1989
• Est. Priority Date: 07/30/1987
• Status: Expired due to Fees

• Current Assignee: Human Performance Technologies, Inc. (Saba Software Incorporated)
• Original Assignee: Human Performance Technologies, Inc. (Saba Software Incorporated)
• Inventors: Au, Jan C.
• Primary Examiner(s): Hindenburg, Max
• Application Number:
  US07/079,582
• Time in Patent Office: 600 Days
• Field of Search: 128/774, 128/779, 128/782, 358/105, 364/413, 364/415
• US Class Current: 600/592
• CPC Class Codes: A61B 5/1038 Measuring plantar pressure during gait
• CPC Class Codes: A63B 22/02 with movable endless bands , e.g. treadmills other training appliances for running on the spot A63B69/0028
• CPC Class Codes: A63B 22/025 electrically, e.g. D.C. motors with variable speed control
• CPC Class Codes: A63B 2220/52 Weight, e.g. weight distribution
• CPC Class Codes: A63B 2220/806 Video cameras
• CPC Class Codes: A63B 2220/807 Photo cameras
• CPC Class Codes: A63B 2220/833 Sensors arranged on the exercise apparatus or sports implement
• CPC Class Codes: A63B 24/0003 Analysing the course of a movement or motion sequences during an exercise or trainings sequence, e.g. swing for golf or tennis

Abstract

A motion analysis system and apparatus incorporates markers which are secured at various joints of the subject'"'"'s body as well as pressure sensitive shoes or insoles which are worn by the subject. The subject is caused to perform motion such as walking or running. While performing this motion, the subject is televised by means of two video cameras. The video signal from the cameras is stored by means of video recorders and then processed on a frame-to-frame basis to provide digitized data. The pressure sensitive insoles provide signals which are processed according to analog to digital conversion techniques whereby a display is also provided which indicates the pressure applied to the subject'"'"'s foot while performing. The remaining data as supplied by the first and second video cameras and which is digitized is then further processed to present various displays showing the gait, the angular position of the various joints of the patient and various other information indicative of the particular walking characteristics of the subject. The data thus produced and processed by the system enables a practitioner to judge the persons'"'"'s walking gait as compared to a normal user.

Claims

1. A motion analysis system of the type operative to analyze the movements of designated body portions of a subject to be monitored as the subject walks along a predetermined path and to particularly analyze the pressure applied to the feet of said subject when traversing said path, comprising:

pressure responsive means secured to the feet of said subject and operative to provide output pressure signals indicative of the force applied to eh subject'"'"'s feet while traversing said path, first computer means coupled to said pressure responsive means and operative to analyze said pressure signals to provide a display of the pressure applied to said subject'"'"'s feet during given selected time intervals as said subject traverses said path and pressure operative means associated with said path and operative to provide an output signal when walked on by said subject with said signal coupled to said first computer means to determine a start of processing.

2. The system according to claim 1, wherein said pressure responsive means includes at least one foot pad worn by said user on a foot thereof said pad containing a plurality of pressure transducers with a first located near the big toe of said user, a second at the arch and a third at the heel whereby each transducer provides an output signal associated therewith and indicative of toe, arch and heel pressure respectively as occurring as said subject traverses said path.

3. The system according to claim 2, further including analog to digital converting means coupled to said pressure transducers for providing separate digital signals indicative of the pressure output of each transducer, with said digital signals stored by said first computer means and processed thereby.

4. The system according to claim 1, wherein said first computer means includes display means for generating a visual display of a subject'"'"'s foot including a display of the areas being monitored according to said pressure signals.

5. The system according to claim 1 further including a triggerable light source coupled to said pressure operative means on said path and operative to provide a burst of light when said pressure operative means is walked on.

6. The system according to claim 6, further including,

at least one television camera monitoring said path and responsive to said burst to provide a first brightness level indicative of said burst for determining a start analysis frame,

storage means coupled to said camera for storing televisions signals as said subject traverses said path,

digitizer means coupled to said storage means for digitizing said stored signals on a frame to frame basis, with a first frame defined by the frame after said burst containing frame,

second computer means responsive to said digitized signals for processing the same to provide a display indicative of the motion of the subject while traversing said path to enable a user to use said second computer display with said first computer display for motion analysis.

7. The system according to claim 6, further including a video monitor coupled to said storage means for providing a display of said stored video signals and means coupled to said video monitor for providing another video signal indicative of said displayed signal for application to said digitizing means.

8. The system according to claim 7, wherein said means coupled to said video monitor includes a television camera operative to monitor said display to provide at an output said another video signal.

9. The system according to claim 6, further including a light pen means coupled to said digitizing means and operative to modify said stored signals prior to digitizing the same.

10. A motion analysis system of the type operative to analyze the motion of designated body portions of a subject to be monitored as the subject walks along a predetermined path and particularly adapted to analyze the gait, joint angles and force between said body portions and the forces exerted on said body portions as said subject traverses said path with said body portions of said subject marked by light indicating markers, said system of the type employing first and second television cameras and associated storage means as video tape recorders associated with each camera for storing the video signal from each camera and including digital means coupled to said storage means for digitizing said video signals by forming a pixel array and computer means coupled to said digital means for processing said digitized signals to provide displays indicative of the motion qualities of said subject as traversing said path with said displays as provided being processed according to said markers, the improvement therewith of apparatus for controlling the processing of said motion analysis system comprising:

pressure operative means associated with said path and operative to provide a burst of light when said subject contacts said means, with said burst of light responded to by said cameras to provide a first reference video signal which when stored provides a reference video frame for said digital means,

video image enhancing means coupled to said storage means and operative to provide an output video signal from said stored video signal, with said output video signal including stabilized sync components for application to said digital means to enable said digital means to provide stabilized digitized output signals, and

processing means associated with said computer means and operative to determine the location of said markers by comparing adjacent pixels in said array with a given pixel for selecting those pixels of a greater intensity and indicative of a marker'"'"'s location.

11. The system according to claim 10, further including:

pressure responsive means coupled to the feet of said subject and operative to provide output signals indicative of the pressure applied to the subject'"'"'s feet when traversing said path, and separate computer means responsive to said burst signal and coupled to said pressure responsive means to process said pressure output signals to provide a display of said signals during selected time intervals as said subject traverses said path.

12. The system according to claim 11, wherein said pressure responsive means includes a right and a left foot pad worn by said subject on each foot, with each pad including a plurality of pressure sensors, with a first sensor located near the toe of said subject, a second near the arch and a third near the heel wherein each sensor on each foot provides an output signal indicating the pressure generated at said location, and

analog to digital conversion means coupled to said sensors and operative to convert said output signals to digital signals for processing said signals to provide said display.

13. The system according to claim 12, wherein said separate computer means is operative to provide a display indicative of the outline of a right and a left foot of a subject and including areas on said display designating said pressure sensor locations, for providing a displayed pressure signal at each location indicative of the pressure at said location during a given time interval as said subject traverses said path.

14. The system according to claim 11, wherein said pressure responsive means includes a pressure mat positioned in said path and operative to provided an output signal when a force is applied thereto indicative of said subject walking on said mat,

a strobe light coupled to said mat and operative to emit a light burst during the presence of said output signal, and control means coupled to said mat and operative to provide a control signal for application to said second computer means.

15. The system according to claim 10, further including light pen means coupled to said processing means and operative to manually mark the location of said markers according to said displayed video signals.

16. The system according to claim 11, wherein said video enhancing means includes a video monitor coupled to said storage means and operative to provide a video display of said stored video signal, a television camera positioned to monitor said display to provide said output video signal for application to said digital means.

17. The system according to claim 16, further including brightness control means coupled to said video monitoring means for adjusting the brightness of said display to enable control of the intensity of said markers as compared to non-marker areas of said display.

18. The system according to claim 16, wherein said television camera is a C.C.D. device.

19. The apparatus according to claim 10, wherein said processing means includes means for comparing the intensity of a given selected pixel with the intensity of surrounding pixels and to select a surrounding pixel of a greater intensity as a correct pixel.