Intensity-modulated light pattern for active stereo
The subject disclosure is directed towards projecting light in a pattern in which the pattern contains components (e.g., spots) having different intensities. The pattern may be based upon a grid of initial points associated with first intensities and points between the initial points with second intensities, and so on. The pattern may be rotated relative to cameras that capture the pattern, with captured images used active depth sensing based upon stereo matching of dots in stereo images.
1. A system comprising:
a projector that projects a light pattern towards a scene, the projector including:
two or more stereo cameras comprising a first stereo camera and a second stereo camera;
a multimode laser; and
a diffractive optical component configured to:
diffract the light pattern from the multimode laser into a dot pattern comprising a first set of points of a higher intensity range and a second set of points of a medium intensity range that is less than the higher intensity range, wherein the second set of points are projected within polygons of the first set of points, wherein the first set of points comprise points of different intensities within the higher intensity range,
rearrange one or more points of the second set of points into modified positions, and
sense the first set of points by one or more stereo cameras.
2. The system of claim 1 , wherein the two or more stereo cameras are configured to sense the first set of points and the second sets of points as left and right stereo camera images.
3. The system of claim 2 , the system further comprising:
an image processing component configured to process the stereo camera images into depth maps.
4. The system of claim 2 , wherein the projector is incorporated into a single device with the two or more stereo cameras.
5. The system of claim 4 , wherein two or more stereo cameras are positioned on opposite sides of the projector.
6. The system of claim 1 , wherein the first set of points, and the second set of points are interleaved via subdivision.
7. The system of claim 1 , wherein at least one of the points of the first set of points or the second set of points is randomly or pseudo-randomly assigned an intensity value within the higher intensity range.
8. The system of claim 7 , wherein assigning intensity values to the points of the first set of points and the second set of points involves applying one or more weighted random techniques to bias assigned intensity values away from values of the medium intensity range.
9. The system of claim 1 , wherein the projected light pattern comprises infrared light for sensing by infrared stereo cameras or visible light for sensing by color stereo cameras.
10. A method of projecting, through a presentation device, a light pattern toward a scene for use in depth sensing, the method comprising:
generating a first set of points oriented in a grid as a collection of polygons;
assigning different intensities to the first set of points within a first intensity range;
generating a second set of points oriented within the polygons of the first set of points;
assigning different intensities to the second set of points within a second intensity range that is lower than the first intensity range;
projecting the first set of points and the second set of points as the light pattern toward the scenes;
rearranging one or more points of the second set of points into modified positions, and
sensing the first set of points by one or more stereo cameras.
11. The method of claim 10 further comprising:
wherein the first set of points are sensed by a right stereo camera and the second set of points are sensed by a left stereo camera.
12. The method of claim 11 wherein the light pattern is outputted by the diffractive component in two instances at different angles rotated toward at least one of the one or more stereo cameras.
13. The method of claim 11 , further comprising:
processing, by an image processing component, the light pattern into a depth map.
14. The method of claim 13 , further comprising extracting matching features from the light pattern.
15. The method of claim 10 , further comprising:
generating a third set of points oriented within the polygons of the first set of points;
assigning different intensities to the third set of points within a third intensity range that differs from the first intensity range and the second intensity range; and
projecting the third set of points as part of the light pattern.
16. The method of claim 10 , further comprising randomly or pseudo-randomly selecting an intensity value within the first intensity range for at least some of the points in the first set of points.
17. The method of claim 10 , wherein the first intensity range comprises a minimum intensity value and a maximum intensity value, the minimum intensity value being numerically smaller than the maximum intensity value.
18. The method of claim 10 wherein said projecting the first set of points and the second set of points as the light pattern includes pulsing at least one of the first set of points or the second set of points.
19. The method of claim 10 , wherein the first set of points are sensed by a right stereo camera and the second set of points are sensed by a left stereo camera.
20. A method comprising:
generating a first set of points oriented in a grid as a collection of polygons;
assigning different intensities to the first set of points within a first intensity range;
generating a second set of points oriented within the polygons of the first set of points;
assigning different intensities to the second set of points within a second intensity range that is higher than the first intensity range;
projecting the first set of points and the second set of points as the light pattern toward the scenes;
rearranging one or more points of the second set of points into modified positions, and
sensing the first set of points by one or more stereo cameras.