Systems and methods of capturing high-resolution images of objects

• US 20070291104A1
• Filed: 06/07/2006
• Published: 12/20/2007
• Est. Priority Date: 06/07/2006
• Status: Abandoned Application

• Current Assignee: Wavetronex, Inc.
• Original Assignee: Wavetronex, Inc.
• Inventors: Petersen, Barry Lee, Chan, Li Shen, Huang, Hui Ping, Chu, Chia Ching, Lee, Hou Hsien, Wang, Tsai Te, Li, Chang Jou
• Application Number:
  US11/448,650
• Publication Number:
  US 20070291104A1
• Time in Patent Office: Days
• US Class Current: 348/14.01
• CPC Class Codes: G01S 3/7865 using correlation of the live video image with a stored image
• CPC Class Codes: G06T 7/277 involving stochastic approaches, e.g. using Kalman filters
• CPC Class Codes: G08B 13/19608 Tracking movement of a target, e.g. by detecting an object predefined as a target, using target direction and or velocity to predict its new position
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• CPC Class Codes: H04N 5/77 between a recording apparatus and a television camera

Abstract

The invention relates to a system of capturing zoom-in images of an object. The system comprises a pan, tilt, zoom (PTZ) camera for capturing a video stream in view; an image-capture device for extracting and digitizing images from the video stream; an object detector for detecting objects in the images from the image-capture device, determining the locations and sizes of the objects and sending the locations and the sizes of the objects to a selector; the selector for determining one of the objects and sending the location and size of the one of the objects to a assessor; the assessor for determining the trajectories required to both align the one of the objects to the center of the image based on the current location of the one of the objects relative to the center and to maximize the size and resolution of the one of the objects according to the current size of the one of the objects, and for sending the trajectories to a translator; the translator for converting the trajectories into a signal stream with a command format that a camera controller can understand and for sending the converted trajectories to the camera controller; and the camera controller for moving and zooming the PTZ camera according to the signal stream, thereby the PTZ camera moves to center on the one of the objects and captures zoomed-in images of the one of the objects from the video stream.

Claims

1. A system, comprising:

a pan, tilt, zoom (PTZ) camera for capturing a video stream in view;

an image-capture device for extracting and digitizing images from the video stream;

an object detector for detecting objects in the images from the image-capture device, determining the locations and sizes of the objects and sending the locations and the sizes of the objects to a selector;

the selector for choosing one of the objects and sending the location and size of the one of the objects to an assessor;

the assessor for determining the trajectories required to both align the one of the objects to the center of the image based on the current location of the one of the objects relative to the center and to maximize the size and resolution of the one of the objects according to the current size of the one of the objects, and for sending the trajectories to a translator;

the translator for converting the trajectories into a signal stream with a command format that a camera controller can understand and for sending the converted trajectories to the camera controller; and

the camera controller for moving and zooming the PTZ camera according to the signal stream,

thereby the PTZ camera moves to center on the one of the objects and captures zoomed-in images of the one of the objects from the video stream.

2. The system of claim 1, further comprising:

recording means for recording the zoomed-in images.

3. The system of claim 1, wherein the object detector uses a direct comparison algorithm.

4. The system of claim 3, wherein the direct comparison algorithm is a face-detection algorithm.

5. The system of claim 1, wherein the object detector uses a motion detection algorithm.

6. The system of claim 1, wherein the object detector initially uses a direct comparison algorithm to find the objects and then uses a template matching technique to continue detecting the objects.

7. The system of claim 1, wherein the object detector initially uses a direct comparison algorithm to find the objects and then uses a neural network technique to continue detecting the objects.

8. The system of claim 1, wherein the object detector initially uses a motion detection algorithm to find the objects and then uses a template matching technique to continue detecting the objects.

9. The system of claim 1, wherein the object detector initially uses a motion detection algorithm to find the objects and then uses a neural network technique to continue detecting the objects.

10. The system of claim 1, wherein the command format is in rectangular coordinates.

11. The system of claim 1, wherein the command format is in polar coordinates.

12. The system of claim 1, wherein the PTZ camera is a device capable of producing a constant stream of images.

13. The system of claim 12, wherein the PTZ camera is a video camera.

14. The system of claim 12, wherein the PTZ camera is a continuously activated still-frame camera.

15. A camera assignment system for assigning one or more systems of claim 1, comprising:

a primary camera for capturing a video stream in view;

a primary image-capture device for extracting and digitizing images from the video stream;

a primary object detector for detecting objects in the images from the primary image-capture device, determining the locations and sizes of the objects and sending the locations and the sizes of the objects to a primary selector;

the primary selector for choosing selected objects to capture from the objects detected by the primary object detector and sending the locations and the sizes of the selected objects to an assignor; and

the assignor for assigning the selected objects to the one or more assessors of the one or more systems of claim 1.

16. The camera assignment system of claim 15, wherein the primary camera and the PTZ cameras are mutually calibrated.

17. The camera assignment system of claim 15, wherein the primary camera is a device capable of producing a constant stream of images.

18. The camera assignment system of claim 17, wherein the primary camera is a video camera.

19. The camera assignment system of claim 17, wherein the primary camera is a continuously activated still-frame camera.

20. A method of using a system of claim 1, comprising the steps of:

(a) capturing an image with the PTZ camera;

(b) searching for the objects in the image;

(c) determining whether any existences of the objects have been detected;

(d) if any existences of the objects have been detected, selecting one of the objects and obtaining its location and size;

(e) calculating the distance of the one of the objects from the center of the image;

(f) determining whether the distance is within a predetermined distance;

(g) if the distance is within a predetermined distance, determining whether the size of the one of the objects reaches a predetermined size; and

(h) if the size of the one of the objects reaches a predetermined size, returning the PTZ camera to an original position.

21. The method of claim 20, further comprising the step of:

(i) deactivating a Track Timer.

22. The method of claim 20, where the object selected in step (d) is the object closest to the center of the captured image.

23. The method of claim 20, further comprising the steps of:

(h1) if the size of the one of the objects does not reach the predetermined size, checking whether the PTZ camera lens full zoom extension is reached; and

(i1) if the PTZ camera lens full zoom extension is not reached, zooming in the PTZ camera stepwise.

24. The method of claim 23, further comprising the step of:

(i2) if the PTZ camera lens full zoom extension is reached, returning the PTZ camera to an original position.

25. The method of claim 24, further comprising the step of:

(j2) deactivating a Track Timer.

26. The method of claim 20, further comprising the steps of:

(g1) if the distance of the one of the objects from the center of the image is not within a predetermined distance, moving the PTZ camera to center on the object.

27. The method of claim 20, further comprising the steps of:

(e1) determining whether a Track Timer is active; and

(f1) if the Track Timer is active, executing step (e).

28. The method of claim 27, further comprising the steps of:

(f2) if the Track Timer is deactivated, starting the Track Timer for a third predetermined time that defines how long to continue the search and zoom function for the object that was originally detected; and

(g2) executing step (e1).

29. The method of claim 20, further comprising the step of:

(d1) if no object is detected, zooming the PTZ camera out stepwise.

30. The method of claim 20, further comprising the steps of:

(d2) if the one of the objects is not detected, determining whether a Track Timer is over a third predetermined time that defines how long to continue the search and zoom-in function for the object that was originally detected; and

(e2) if the Track Timer is over the third predetermined time, returning the PTZ camera to an original position.

31. The method of claim 30, further comprising the steps of:

(e3) if the Track Timer is not over the third predetermined time, zooming out the PTZ camera stepwise.

32. The method of claim 20, further comprising the steps of:

(e4) if the one of the objects is not detected, determining whether a Backup Step Timer is over a fourth predetermined time that determines the length of time to search at a given resolution scale before abandoning the search at that scale and retracting the zoom lens stepwise;

(f4) if the Backup Step Timer is over the fourth predetermined time, starting the Backup Step Timer; and

(g4) zooming out the PTZ camera stepwise.

33. The method of claim 32, further comprising the step of:

(f5) if the Backup Step Timer is not over the fourth predetermined time, maintaining the current camera position.

34. The method of claim 30, further comprising the steps of:

(e6) if the Track Timer is not over the third predetermined time, determining whether a Backup Step Timer is over a fourth predetermined time that determines the length of time to search at a given resolution scale before abandoning the search at that scale and retracting the zoom lens stepwise;

(f6) if the Backup Step Timer is over the fourth predetermined time, starting the Backup Step Timer; and

(g6) zooming out the PTZ camera stepwise.

35. The method of claim 34, further comprising the step of:

(f7) if the Backup Step Timer is not over the fourth predetermined time, maintaining the PTZ camera in its current position.

36. The method of claim 20, further comprising the step of:

(d′

) recording images one step prior to the execution of step (e).

37. A method of using a camera assignment system of claim 15, comprising the steps of:

(a) capturing an image with the primary camera;

(b) searching for objects in the image;

(c) determining whether any objects have been detected;

(d) if any objects have been detected, placing them in a list of detected objects;

(e) determining whether any of the one or systems of claim 1 is available;

(f) if one of the one or more systems of claim 1 is available, selecting an associated object from the list of detected objects;

(g) initializing the one of the one or more systems of claim 1;

(h) removing the associated object from the list of detected objects;

(i) determining if any objects remain in the list of detected objects; and

(j) if any objects remain in the list of detected objects, executing step (e).

38. The method of claim 37, wherein the associated object selected in step (f) is the object nearest to the center of the image.

39. The method of claim 37, further comprising the step of:

(d1) if no object is detected, executing step (a).

40. The method of claim 37, further comprising the step of:

(f1) if no system is available, executing step (a).

41. The method of claim 37, further comprising between the steps (a) and (b) a step of:

(j1) if no objects remain in the list of detected objects, executing step (a).

42. The method of claim 37, further comprising the steps of:

(b1) applying a mask overlay created from the list of masks onto the captured image, wherein masked regions effectively hide corresponding areas in the captured image.

43. The method of claim 37, further comprising between the steps (d) and (e) steps of:

(e2) determining if any regions in the image covered by masks in a list of masks and the regions in the image covered by detected objects in the list of detected objects overlap by a predetermined threshold;

(f2) if any regions in the image covered by masks in a list of masks and the regions in the image covered by detected objects in the list of detected objects overlap by a predetermined threshold, removing the respective objects from the list of detected objects; and

(g2) executing step (i).

44. The method of claim 43, further comprising the steps of:

(f3) if none of the regions in the image covered by masks in the list of masks and the regions in the image covered by detected objects in the list of detected objects overlap by a predetermined threshold, executing step (e).

45. The method of claim 37, further comprising the steps of:

(i2) adding a mask to the list of masks corresponding to the region occupied by the associated object;

(j2) starting a Mask Timer associated with the mask added to the list of masks;

(k2) removing mask(s) from the list of masks when the mask'"'"'s associated Mask Timer is over a second predetermined time that determines how long to wait before removing a mask that is used to identify a previously identified object; and

(l2) executing step (i).

46. The method of claim 37, wherein the step of initializing the one of the one or more systems of claim 1 comprises:

capturing an initial image using the PTZ camera of the one of the one or more systems of claim 1;

transferring the calibrated size and positional information to the assessor of the one of the one or more systems of claim 1; and

using object size and positional information to initially align the object in the one of the one or more systems of claim 1.

47. The method of claim 37, wherein the primary camera and the one or more PTZ cameras are mutually calibrated.