Method and apparatus for detecting and quantifying motion of a body part

• US 5,214,711 A
• Filed: 04/23/1992
• Issued: 05/25/1993
• Est. Priority Date: 08/24/1990
• Status: Expired due to Term

• Current Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Original Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Inventors: Cheung, John Y., Neely, John G. H.
• Primary Examiner(s): Mancuso, Joseph
• Application Number:
  US07/872,805
• Time in Patent Office: 397 Days
• Field of Search: 382/6, 382/54, 382/42, 382/30, 382/48, 382/44, 382/18, 382/1, 364/413.13, 364/413.16, 364/413.22, 364/413.23, 364/413.27, 364/413.02, 358/185
• US Class Current: 382/107
• CPC Class Codes: G06T 7/254 involving subtraction of images

Abstract

A method for detecting and quantifying motion of a body part of an individual or animal, such as an individual'"'"'s face or portion thereof. A digitized image of the body part in a reference position is produced (referenced image). A digitized image of the body part in a changed position then is produced (changed image). The referenced image is compared with the changed image to determine movement parameters indicating the movement of the body part from the referenced image to the changed image.

Claims

1. A method for detecting surface deformation of a substantially stationary body part comprising:

producing a digitized frame of the substantially stationary body part in an undeformed surface reference position of the body part, identified as a digitized control frame;

producing a digitized frame of the body part in a surface deformed position of the body part, different from the undeformed surface position of the body part in the reference position, identified as a digitized changed frame, where the deformed position is produced substantially by musculature movements of the individual; and

comparing the digitized control frame with the digitized changed frame and determining surface deformations over a defined surface area of the body part from the reference position to the deformed position.

2. The method of claim 1 wherein the step of producing the digitized control frame further comprises:

videoing using a video camera the body part to produce video images of the body part in an analog format;

grabbing a frame of the video images in the analog format showing the body part in the control position; and

digitizing the frame of the video image in the analog format and in the control position to produce the digitized control frame; and

wherein the step of producing the digitized changed frame further comprises;

videoing using a video camera the body part to produce video images of the body part in an analog format;

grabbing a frame of the video images in the analog format showing the body part in the changed position; and

digitizing the frame of the video image in the analog format and in the changed position to produce the digitized control frame.

3. The method of claim 1 wherein the step of producing the digitized control frame further comprises:

taking a image via a still frame camera of the body part in the control position to produce a still frame image in a digital format thereby producing the digitized control frame; and

wherein the step of producing the digitized changed frame further comprises;

taking a image via a still frame camera of the body part in the changed position to produce a still frame image in a digital format thereby producing the digitized changed frame.

4. The method of claim 1 wherein the step of producing the digitized control frame further comprises:

videoing using a video camera the body part to produce video images of the body part in an analog format and outputting the video images of the body part in the analog format;

recording the video images in the analog format outputted via the video camera on a video medium in an analog format;

playing back the video images recorded on the video medium for outputting the video images in the analog format;

grabbing a frame of the video images in the analog format showing the body part in the control position; and

digitizing the frame of the body part in the control position to produce the digitized control frame; and

wherein the step of producing the digitized changed frame further comprises;

videoing using a video camera the body part to produce video images of the body part in an analog format and outputting the video images of the body part in the analog format;

recording the video images in the analog format outputted via the video camera on a video medium in an analog format;

playing back the video images recorded on the video medium for outputting the video images in the analog format; and

grabbing a frame of the video images in the analog format showing the body part in the changed position; and

digitizing the frame of the body part in the changed position to produce the digitized changed frame.

5. The method of claim 1 wherein, prior to the step of comparing the digitized control frame with the digitized changed frame, the method further comprises:

equalizing the digitized control frame to produce an equalized digitized control frame having an average intensity throughout and with a predetermined distribution of pixel intensity variations;

equalizing the digitized changed frame to produce an equalized digitized changed frame having an average intensity throughout and with a predetermined distribution of pixel intensity variations.

6. The method of claim 1 wherein the step of comparing the digitized control frame with the digitized changed frame further comprises:

subtracting out the common areas of pixel values between the digitized control frame and the digitized changed frame to produce a digitized compare frame.

7. The method of claim 1 wherein the step of comparing the digitized control frame with the digitized changed frame is further defined as producing a digitized compare frame, and wherein the step of comparing the digitized control frame and the digitized changed frame further comprises:

counting the pixels in the digitized compare frame having a brightness value above a predetermined threshold level to provide the movement parameter indicating movement of the body part from the control position to the changed position.

8. The method of claim 1 wherein the step of comparing the digitized control frame with the digitized changed frame is further defined as producing a digitized frame, and wherein the step of comparing the digitized control frame and the digitized changed frame further comprises:

designating a control area of interest in the digitized compare frame; and

counting the pixels having a brightness value above a predetermined threshold level in the area of interest.

9. The method of claim 1 wherein the step of comparing the digitized control frame with the digitized changed frame, is further defined as producing a digitized compare frame, and wherein the step of comparing the digitized control frame and the digitized changed frame further comprises:

designating a control area of interest in the digitized compare frame;

designating a changed area of interest in the digitized compare frame; and

counting the pixels having a brightness value above a predetermined threshold level in the control level in the control area of interest and counting the pixels having a brightness value above a predetermined threshold level in the changed area of interest to provide a movement parameter indicating a difference in the movement in the control area of interest with respect to the changed area of interest.

10. The method of claim 1 wherein the step of comparing the digitized control frame with the digitized changed frame is further defined as producing a digitized compare frame, and wherein the step of comparing the digitized control frame and the digitized changed frame further comprises:

enhancing all of the pixels in the digitized compare frame having a brightness level above a predetermined value whereby all of the pixels having a brightness value above a predetermined value appear to be more bright.

11. The method of claim 1 wherein the step of comparing the digitized control frame with the digitized changed frame is further defined as producing a digitized compare frame, and wherein the step of comparing the digitized control frame and the digitized changed frame further comprises:

replacing all of the pixels in the digitized compare frame having a brightness value below a predetermined threshold level with a substantially null value and enhancing the pixels in the digitized compare frame having a brightness value above a predetermined threshold level whereby the pixels in the digitized compare frame having a brightness value above the predetermined threshold level appear more bright.

12. The method of claim 1 wherein the step of comparing the digitized control frame with each of the digitized changed frame further comprises producing a plurality of digitized compare frames with each digitized compare frame being produced as a result of the comparison of the digitized control frame with one of the digitized changed frames, and wherein the step of comparing each digitized changed frame with the digitized control frame further comprises:

enhancing all of the pixels in each of the digitized compare frames having a brightness level above a predetermined value whereby all of the pixels having a brightness value above a predetermined value appear to be more bright.

13. A method for detecting and quantifying surface deformations of a substantially stationary body part comprising:

producing a plurality of digitized frames of the substantially stationary body part as the body part is surface deformed from one surface deformed position to another surface deformed position, the deformation being a result substantially of muscular movements of the individual, and designating one of the digitized images as a digitized control frame and the remaining digitized frames as digitized changed frames; and

comparing each digitized changed frame with the digitized control frame to determine shape changes over a defined surface area for each comparison, with each of the determined shape changes over the defined surface area being indicative of the surface deformations over the defined surface area of the body part between the digitized changed frame compared with the digitized control frame.

14. The method of claim 13 wherein the step of producing the digitized frames further comprises:

videoing using a video camera the body part as it is being moved from one position to another position to produce video images of the body part in an analog format;

grabbing a plurality of frames of the video images in the analog format showing the body part as the body part is being moved from one position to another position; and

digitizing each of the frames to produce the digitized frames with one of the digitized frames being designated the digitized control frame.

15. The method of claim 13 wherein the step of producing the digitized frames including the digitized control frame further comprises:

taking a plurality of images via a still camera of the body part as the body part is being moved from one position to another position to produce a still frame image in a digital format thereby producing the digitized frames including the digitized control frame.

16. The method of claim 13 wherein the step of producing the digitized frames including the digitized control frame further comprises:

videoing using the video camera the body part as the body part is moved from one position to another position to produce video images of the body part in an analog format and outputting the video images of the body part in the analog format;

recording the video images in the analog format outputting via the video camera on a video medium in an analog format;

playing back the video images recorded on the video medium for outputting the video images in the analog format; and

grabbing a plurality of frames of the video images in the analog format showing the body part as the body part is being moved from one position to another position; and

digitizing the frames of the body part to produce the digitized frames including the digitized control frame.

17. The method of claim 13 wherein, prior to the step of comparing the digitized control frame with the digitized changed frame, the method further comprises:

equalizing the digitized control frame and the digitized changed frames to produce a digitized control frame and digitized changed frames with each having an average intensity throughout and with a predetermined distribution of pixel intensity variations.

18. The method of claim 13 wherein the step of comparing the digitized control frame with each of the digitized changed frame further comprises producing a plurality of digitized compare frames with each digitized compare frame being produced as a result of the comparison of the digitized control frame with one of the digitized changed frames, and wherein the step of comparing each digitized changed frame with the digitized control frame further comprises:

designating a control area of interest in each of the digitized compare frame;

counting the pixels having a brightness value above a predetermined level in each of the areas of interest.

19. The method of claim 13 wherein the step of comparing the digitized control frame with each of the digitized changed frame further comprises producing a plurality of digitized compare frames with each digitized compare frame being produced as a result of the comparison of the digitized control frame with one of the digitized changed frames, and wherein the step of comparing each digitized changed frame with the digitized control frame further comprises:

replacing all of the pixels in each digitized compare frame having a brightness value below a predetermined threshold level with a substantially null value and enhancing the pixels in each of the digitized compare frames having a brightness value above a predetermined threshold level whereby the pixels in each of the digitized compare frames having a brightness value above the predetermined threshold level appear more bright.

20. A method for detecting surface deformation of a substantially stationary body part comprising:

producing a digitized frame of the substantially stationary body part of the individual and designating a part of the frame as a digitized control frame and one other part of the frame as digitized changed frame; and

comparing the digitized control frame with the digitized changed frame and determining surface deformation over a defined surface area of the body part from the digitized control frame to the digitized changed frame where the surface deformations between the digitized control frame and the digitized changed frame are produced by muscular movements of the individual.