System and method for performing motion capture by strobing a fluorescent lamp
View Patent ↗A system and method are described for performing motion capture on a subject using fluorescent lamps. For example, a system according to one embodiment of the invention comprises: a synchronization signal generator to generate one or more synchronization signals; one or more fluorescent lamps configured to strobe on and off responsive to a first one of the one or more synchronization signals, the fluorescent lamps charging phosphorescent makeup, paint or dye applied to a subject for a motion capture session; and a plurality of cameras having shutters strobed synchronously with the strobing of the light source to capture images of the phosphorescent paint, wherein the shutters are open when the light source is off and the shutters are closed when the light source is on.
1. A system comprising:
a synchronization signal generator to generate one or more synchronization signals;
one or more fluorescent lamps configured to strobe on and off responsive to a first one of the one or more synchronization signals, the fluorescent lamps illuminating makeup, markers, paint or dye applied to a subject for a motion capture session; and
a first plurality of cameras having shutters strobed synchronously with the strobing of the light source to capture sequences of images of the makeup, markers, paint or dye as the subject moves or changes facial expressions during a performance, wherein the shutters are open when the light source is off and the shutters are closed when the light source is on.
2. The system as in claim 1 further comprising:
an image processing device generating motion data representing the movement of the subject using the tracked movement of the makeup, markers, paint or dye.
3. The system as in claim 1 wherein the subject is a performer and wherein makeup, markers, paint or dye is applied in a random pattern to the performer's face.
4. The system as in claim 1 wherein the markers are applied at specified areas of the performer's body.
5. The system as in claim 1 further comprising:
a second plurality of cameras having shutters strobed synchronously with the strobing of the fluorescent lamps to capture images of the performer, wherein the shutters of the second plurality of cameras are open when the fluorescent lamps are on and the shutters of the second plurality of cameras are closed when the fluorescent lamps are off.
6. The system as in claim 5 wherein the first plurality of cameras are grayscale cameras and the second plurality of cameras are color cameras.
7. The system as in claim 1 further comprising:
a ballast circuit electrically coupled to a power source and to at least one of the one or more fluorescent lamps, the ballast circuit configured to provide power to the fluorescent lamp to turn the fluorescent lamp on; and
a synchronization control circuit electrically coupled to the synchronization signal generator and to the ballast circuit, the synchronization control circuit to receive one of the synchronization signals from the synchronization signal generator and to responsively cause the ballast circuit to turn the fluorescent lamp on and off.
8. The system as in claim 1 wherein strobing the shutters comprises opening the shutters for a first period of time and closing the shutters for a second period of time, the second period of time being of a different duration than the first period of time.
9. The system as in claim 8 wherein the first period of time is longer than the second period of time.
10. The system as in claim 1 wherein the camera shutters are controlled by synchronization signals from a computer system.
11. The system as in claim 5 further comprising an image processing device separating the images captured by the first plurality of cameras from the images captured by the second plurality of cameras to generate two separate sets of image data.
12. The system as in claim 5 wherein the first plurality of cameras have a sensitivity which is different from the second plurality of cameras.
13. The system as in claim 5 wherein the second plurality of cameras are controlled to open their shutters for a relatively shorter period of time when the fluorescent lamps are on; and the first plurality of cameras are controlled to open their shutters for a relatively longer period of time when the fluorescent lamps are off.
14. The system as in claim 5 wherein the second plurality of cameras comprise color cameras and the first plurality of cameras comprise grayscale cameras.
15. The system as in claim 14 wherein the grayscale cameras have a relatively higher sensitivity than the color cameras.
16. The system as in claim 14 wherein two different synchronization signals are used to control the shutters of the color and grayscale cameras.
17. The system as in claim 16 wherein the different synchronization signals are 180 degrees out of phase.
18. The system as in claim 1 wherein strobing the shutters further comprises:
opening the shutters for a period of time when the fluorescent lamps are on to capture images of the performer's face and/or body.
19. The system as in claim 1 wherein after being opened to capture a first non-lit image with the fluorescent lamps off, the shutters of the first plurality of cameras are closed and then opened again when the fluorescent lamps are on to capture a lit image with the fluorescent lamps on, and then closed and then opened again with the fluorescent lamps off to capture a second non-lit image.
20. The system as in claim 18 wherein strobing the shutters comprises opening the shutters for a first period of time and closing the shutters for a second period of time, wherein the first period of time is not equal to the second period of time.
21. The system as in claim 19 further comprising:
an image processing device to separate the image frames captured while the fluorescent lamps are off from the image frames captured when the fluorescent lamps are on to generate two separate sets of image data.
22. The system as in claim 18 wherein sensitivity of the cameras is alternated between capturing the image frames when the fluorescent lamps are on and the image frames when the fluorescent lamps are off.
23. The system as in claim 20 wherein the shutters are opened for a relatively shorter period of time when the fluorescent lamps are on; and
wherein the shutters are opened for a relatively longer period of time when the fluorescent lamps are off.
24. The system as in claim 1 wherein the makeup, paint or dye comprises phosphorescent makeup, paint, dye or other material.
25. The system as in claim 24 where the fluorescent lamps are used to charge the phosphorescent makeup, paint, dye or other material.
26. The system as in claim 5 wherein the strobing of first plurality of cameras and the fluorescent lamps are timed to ensure that the shutters of the first plurality of cameras do not open until the light emanated from the fluorescent panels reaches a minimum threshold value.
27. The system as in claim 1 wherein the makeup or dye includes phosphor.
28. The system as in claim 27 wherein the phosphor comprises ZnS:Cu.
29. The system as in claim 27 wherein the phosphor comprises SrAl2O4:Eu 2+ , Dy 3+ .
30. The system as in claim 27 wherein the phosphor comprises SrAl 2 O 4 :Eu 2+ .