Method for capturing images comprising a measurement of local motions
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.
1. A video imager comprising:
a first region equipped with light-sensitive cells for capturing images; and
a second region having a plurality of unidirectional motion sensors adjacent to respective edges of the first region, enabling local motions to be measured on edges of the images simultaneously with the capture of the images, all of the unidirectional motion sensors in the second region having a detection axis oriented in a first direction with respect to the respective adjacent edge, wherein the video imager is configured to supply local motion data in addition to video data proceeding from the light-sensitive cells.
2. The imager according to claim 1 , comprising circuits for collecting local motion data supplied by the motion sensors, and for supplying a temporal series of local motion data.
3. The imager according to claim 1 , wherein the first region comprises circuits for image acquisition in progressive mode, and the second region comprises circuits for local motion data acquisition in progressive mode, the acquisition of the local motion data associated with a current image extending 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 current image.
4. The imager according to claim 1 , wherein the second region surrounds the first region.
5. The imager according to claim 1 , wherein the plurality of motion sensors comprises groups of motion sensors each comprising a single row of sensors.
6. The imager according to claim 1 wherein the first direction is a direction parallel to the respective adjacent edge.
7. The imager according to claim 1 , wherein each motion sensor comprises:
at least two photoreceptors supplying electric signals varying according to a light intensity received,
a correlation circuit for producing at least one local motion signal according to the electric signals, and
an integrator circuit for supplying a mean value of the local motion signal, cyclically receiving a reset signal.
8. A video imager comprising:
means for capturing a first video image and a second video image; and
means for measuring local motions on edges of the images simultaneously with the capturing of the images, wherein the video imager is configured to supply local motion data in addition to video data and the means for measuring local motions measures only motions along an axis oriented along a first direction with respect to adjacent edges of the images.
9. The video imager of claim 8 , wherein:
the means for capturing the first and second video images comprises a first plurality of light-sensitive cells; and
the means for measuring local motions comprises a second plurality of cells, each cell in the second plurality of cells comprising a plurality of photoreceptors and means for providing an indication of a displacement speed of an image point.
10. The video imager of claim 9 , wherein the second plurality of cells surrounds the first plurality of cells.
11. The video imager of claim 9 , wherein the means for providing the indication of the displacement speed comprises:
a first edge detector coupled to a first one of the plurality of photoreceptors;
a first pulse shaper coupled to the first edge detector;
a second edge detector coupled to a second one of the plurality of photoreceptors; and
a second pulse shaper coupled to the second edge detector.
12. A video imager, comprising:
a plurality of light sensitive cells configured to capture first and second video images;
a plurality of unidirectional motion sensors adjacent to the plurality of lights sensitive cells, all of which are configured to measure local motions along an axis oriented in a first direction with respect to adjacent edges of the captured video images, the motion sensors having:
a plurality of photoreceptors;
a first edge detector coupled to a first one of the plurality of photoreceptors;
a first pulse shaper coupled to the first edge detector;
a second edge detector coupled to a second one of the plurality of photoreceptors; and
a second pulse shaper coupled to the second edge detector.
13. The video imager of claim 12 wherein the plurality of motion sensors surround the plurality of light sensitive cells.
14. The video imager of claim 12 wherein the first direction is a direction parallel to an adjacent edge.
15. The video imager of claim 8 wherein the first direction is a direction parallel to a respective adjacent edge.