METHOD AND DEVICE FOR MONITORING PHASE SHIFTING BETWEEN STEREOSCOPIC CAMERAS

• US 20130229497A1
• Filed: 11/03/2011
• Published: 09/05/2013
• Est. Priority Date: 11/05/2010
• Status: Active Grant

• Current Assignee: Transvideo Co.
• Original Assignee: Transvideo Co.
• Inventors: Delacoux, Jacques
• Granted Patent: US 9,516,297 B2
• Time in Patent Office: Days
• US Class Current: 348/47
• CPC Class Codes: H04N 13/296 Synchronisation thereof; Control thereof
• CPC Class Codes: H04N 5/073 for mutually locking plural sources of synchronising signals, e.g. studios or relay stations

Abstract

A method and device for monitoring phase shifting between stereoscopic cameras. The device for monitoring phase shifting between the images from the stereoscopic cameras includes: a circuit (100) for characterizing the phase shift, which implements the method and is connected to the output terminals of the stereoscopic cameras (G, D); and a monitor (106) for displaying video images, including resources (63) for displaying the images (61, 62) one on top of the other, the image being generated by the cameras and resources (90, 94) for displaying the values (H, V) characterizing the phase shift in relation with the images.

Claims

1. A method for monitoring phase shifting between stereoscopic cameras (2, 3), which comprises:

measuring the phase difference (Dt) between at least a part (10) of a video signal originating from a first stereoscopic camera (2) and a time reference as a corresponding part (11) of the video signal originating from at least one other stereoscopic camera (3);

characterizing the synchronization error (H, D) between the cameras monitored on the basis of said at least one phase difference; and

using the characterization of the synchronization error to monitor said cameras, and/or the video signals originating from said cameras.

2. The method as claimed in claim 1, wherein the step of measuring the phase difference comprises a step for detecting a time reference of the first pixel of a digital video frame, of a digital video line or frame.

3. The method as claimed in claim 1, wherein the step of measuring the phase difference comprises a step for detecting a time reference of the start of a digital video line or frame.

4. The method as claimed in claim 1, wherein the step of characterization of the synchronization error comprises a step for counting the pixels being read belonging to a line and/or for counting the lines being read belonging to a frame produced by at least one of the cameras.

5. The method as claimed in claim 1, wherein the step of characterization of the synchronization error comprises a step for forming the difference between the instantaneous counting of the pixels of a line being captured of at least one camera and a first reference clock as the instantaneous counting of the pixels of a line being captured of at least one other camera and/or to form the difference between the instantaneous counting of the lines of a frame being read for capture of at least one camera and a first reference clock as the instantaneous counting of the lines of a frame being captured of at least one other camera.

6. The method as claimed in claim 1, wherein the step for using the characterization of the phase shift between cameras comprises a step for reinitializing at least one of the video cameras at least when a value characterizing the synchronization error exceeds a determined threshold.

7. The method as claimed in claim 1, wherein the step for using the characterization of the phase shift between cameras comprises a step for displaying on a display device a graphical representation of the characterization of the phase shift of at least one of the images of one of said cameras in relation to a phase reference as the signal of another camera.

8. The method as claimed in claim 1, wherein the step for using the characterization of the phase shift between cameras comprises a step for recording the original streams of the digital images on digital memories, then reading them in synchronism by shifting the reading of at least one of the recorded images of the characterization value of its phase shift in relation to the readings of the other recorded images.

9. The method as claimed in claim 1, wherein the step for using the characterization of the phase shift comprises a step for recording the reading streams of the resynchronized digital images.

10. The method as claimed in claim 1, wherein the step for using the characterization of the phase shift between cameras comprises a step for adding information concerning the instantaneous phase shift recorded for at least a part of the reading data to the reading data of the resynchronized digital images.

11. A device for monitoring the phase shifting between the images originating from stereoscopic cameras which comprises:

a phase shift characterization circuit (100) carrying out the method as claimed in claim 1 and connected to the output terminals of said stereoscopic cameras (G, D); and

a video image display monitor (106) comprising resources for the superimposed display (63) of the images (61, 62) generated by said cameras and resources (90, 94) to display characterization values (H, V) of said phase shift in relation to said images.

12. The device as claimed in claim 11, wherein the resources for displaying values characterizing said phase shift comprise at least a generator of graphical symbols (90) of the instantaneous phase of at least one image, a circuit to display said graphical symbols in an instantaneous position representing the instantaneous phase (91) and/or a circuit to display an alphanumeric value representing said instantaneous phase and/or the instantaneous phase shift (92), and the resources to display values characterizing said phase shift are associated with a horizontal shift and/or a vertical shift of the images of the associated cameras.

13. The device as claimed in claim 11, further comprising a circuit for triggering at least one signal (109) to re-initialize at least one of the associated video cameras connected to the phase shift characterization circuit (100) which comprises a circuit for testing at least one phase value and/or phase shift value at a programmed threshold value for triggering a reinitialization signal transmitted to at least one camera.

14. The device as claimed in claim 11, wherein the phase shift characterization circuit (100) comprises a means (46, 50, 55) for reading in resynchronization the signals (G′

, D′

) representing the images produced by said cameras, which is connected to a recorder (105) of the signals representing the images produced by said cameras and resynchronized.

15. The device as claimed in claim 14, wherein the phase shift characterization circuit comprises a means for producing metadata describing at least a part of the instantaneous phase shifts and recording them with the signals representing the images produced by said cameras (G, D) and/or resynchronized (G′

, D′

).