METHOD FOR CAPTURING IMAGES COMPRISING A MEASUREMENT OF LOCAL MOTIONS

• US 20110194734A1
• Filed: 03/09/2011
• Published: 08/11/2011
• Est. Priority Date: 02/17/2005
• Status: Active Grant

• Current Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Inventors: Martin, Lionel, Gensolen, Fabrice, Cathebras, Guy
• Granted Patent: US 8,139,823 B2
• Time in Patent Office: Days
• US Class Current: 382/107
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6811 based on the image signal
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors
• CPC Class Codes: H04N 23/682 Vibration or motion blur correction
• CPC Class Codes: H04N 25/707 Pixels for event detection

Abstract

A method for capturing a sequence of video images, using an imager including an estimation of the parameters of a model of global motion between successive images. The method may include measurement of local motions on edges of the images, with the estimation of the parameters of the global motion model performed using the result of the measurement of local motions on the edges of the images.

Claims

1. A method, comprising:

capturing video images by,

measuring local motions on edges of the images;

estimating parameters of a global motion model using results of the measurement of local motions on the edges of the images;

calculating local motions using the estimated parameters of the global motion model; and

comparing the local motions calculated and the local motions measured on the edges of the image, wherein the estimating, calculating and comparing are performed by one or more configured electronic devices.

2. The method of claim 1, further comprising:

determining whether the estimated parameters of the global motion model at least partially coincide with the local motions measured.

3. The method of claim 1, wherein the measurement of local motions is taken on four edges of the image.

4. The method of claim 1, wherein the measurement of local motions on the edges of the images is taken according to a single motion detection axis parallel to the edges of the images, and according to two directions of displacement along the detection axis.

5. The method of claim 1, comprising providing and using an imager comprising:

a central region for capturing images comprising light-sensitive cells; and

a peripheral region equipped with motion sensors, supplying local motion data.

6. The method of claim 5, wherein the peripheral region completely surrounds the central region.

7. The method of claim 5, wherein the peripheral region comprises groups of motion sensors each comprising a single row of motion sensors.

8. The method of claim 5, wherein the peripheral region comprises unidirectional motion sensors having a single motion detection axis and two displacement detection directions along the motion detection axis.

9. The method of claim 5, wherein:

the capturing of the images is performed in progressive mode, and

acquisition of local motion data associated with an image is performed in progressive mode and extends in a time window delimited by a first instant corresponding substantially to a start of the capture of a previous image and a second instant corresponding substantially to an end of the capture of the image.

12. The method of claim 1, wherein the parameters of the global motion model comprise an angle of rotation, a zoom factor, and two parameters of translation according to orthogonal axes.

13. The method of claim 1, comprising a step of stabilizing the video images conducted using the estimated parameters of the global motion model.

14. The method of claim 1, further comprising:

compensating for local motions attributable to an animated object entering the images.

10. A method, comprising:

capturing a first and a second image;

measuring local motions at points of a first set of image points, during an acquisition period extending between the capture of the first image and the capture of the second image; and

estimating parameters of a global motion model by;

calculating presumed positions of the image points in the first set of image points on the second image according to their positions on the first image, using the local motions measured on the edges of the image, to obtain a second set of image points;

calculating initial parameters of the global motion model using the second set of image points;

calculating theoretical positions of the image points in the first set on the second image according to their positions on the first image, using the initial parameters of the global motion model, to obtain a third set of image points;

comparing the second and third sets of image points; and

removing, from the first set of image points, image points having a deviation greater than a first threshold between their positions in the second set of image points and their positions in the third set of image points, if the number of image points to be removed is above a second threshold, wherein the estimating is performed by a configured electronic device.

11. The method of claim 10, comprising calculating new parameters of the global motion model, after removing image points from the first set of image points.

34. The method of claim 10 wherein the parameters of the global motion model comprise an angle of rotation, a zoom factor, and two parameters of translation according to orthogonal axes.

15-21. -21. (canceled)

22. A video image acquisition device, comprising:

an imager having;

a first region equipped with light-sensitive cells for capturing images; and

a second region on an edge of the first region, equipped with motion sensors enabling local motions to be measured on the edges of the images simultaneously with the capture of the images, wherein the video imager is configured to supply local motion data in addition to video data; and

a calculating device configured to;

estimate parameters of a model of global motion between successive images supplied by the imager, using a result of a measurement of local motions on edges of the images taken by the imager;

calculate local motions using the estimated parameters of the global motion model; and

compare the local motions calculated and the local motions measured on the edges of the image.

23. The device according to claim 22, wherein the calculating device is configured to estimate the parameters of the global motion between a first and a second image by:

from an initial set of image points on the first image, calculating presumed positions of the image points on the second image according to their positions on the first image, using the local motions measured by the imager, to obtain a second set of image points;

calculating initial parameters of the global motion model using the second set of image points;

calculating theoretical positions of the image points in the initial set on the second image according to their positions on the first image, using the initial parameters of the global motion model, to obtain a third set of image points;

comparing the second and third sets of image points; and

selectively removing from the first set of image points, image points having a deviation greater than a first threshold between their positions in the second set and their positions in the third set, when the number of image points having the deviation greater than the first threshold is above a second threshold.

24. The device according to claim 23, wherein the calculating device is configured to calculate new parameters of the global motion model, after image points having the deviation greater than the first threshold have been removed from the first set of image points.

25. The device according to claim 22, wherein the parameters of the global motion model comprise an angle of rotation, a zoom factor, and two parameters of translation according to orthogonal axes.

26. The device according to claim 22, wherein the calculating device is configured to stabilize video images using the estimated parameters of the global motion model.

27-30. -30. (canceled)

31. A non-transitory computer-readable memory medium containing instructions for causing an imaging device to process video images by generating control signals to cause the imaging device to:

measure local motions on edges of the images;

estimate parameters of a global motion model using results of the measurement of local motions on the edges of the images;

calculate local motions using the estimated parameters of the global motion mode; and

compare the local motions calculated and the local motions measured on the edges of the image.

32. The non-transitory computer-readable memory medium of claim 31, wherein the instructions further cause the imaging device to:

capture a first and a second image, wherein

measuring local motions comprises measuring local motions at points of a first set of image points during an acquisition period extending between the capture of the first image and the capture of the second image; and

estimating parameters of a global motion model comprises;

calculating a second set of image points using the local motions measured on the edges of the image;

calculating initial parameters of the global motion model using the second set of image points;

calculating a third set of image points using the initial parameters of the global motion model;

comparing the second and third sets of image points; and

modifying the initial parameters of the global motion model based on the comparison of the second and third sets of image points.

33. The non-transitory computer-readable medium of claim 31 wherein the parameters of the global motion model comprise an angle of rotation, a zoom factor, and two parameters of translation according to orthogonal axes.