Automatically Expanding the Zoom Capability of a Wide-Angle Video Camera

• US 20120038776A1
• Filed: 06/17/2011
• Published: 02/16/2012
• Est. Priority Date: 07/19/2004
• Status: Active Grant

• Current Assignee: Grandeye Limited (Oncam Global Group AG)
• Original Assignee: Grandeye Limited (Oncam Global Group AG)
• Inventors: Cetin, Ahmet Enis, Ahiska, Bartu, Davey, Mark Kenneth
• Granted Patent: US 8,405,732 B2
• Time in Patent Office: Days
• US Class Current: 348/159
• CPC Class Codes: G08B 13/19606 Discriminating between target movement or movement in an area of interest and other non-signicative movements, e.g. target movements induced by camera shake or movements of pets, falling leaves, rotating fan
• 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: G08B 13/19628 of wide angled cameras and camera groups, e.g. omni-directional cameras, fish eye, single units having multiple cameras achieving a wide angle view
• CPC Class Codes: G08B 13/19643 wherein the cameras play different roles, e.g. different resolution, different camera type, master-slave camera
• CPC Class Codes: G08B 13/19686 Interfaces masking personal details for privacy, e.g. blurring faces, vehicle license plates
• CPC Class Codes: G08B 13/19689 Remote control of cameras, e.g. remote orientation or image zooming control for a PTZ camera
• 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 23/90 Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

Abstract

A system for automatically expanding the zoom capability of a wide-angle video camera using images from multiple camera locations. One preferred embodiment achieves this using images from the wide-angle video camera that are analyzed to identify regions of interest (RoI). Pan-Tilt-Zoom (PTZ) controls are then sent to aim slave cameras toward the RoI. Processing circuitry is then used to replace the RoI from the wide-angle images with the higher-resolution images from one of the slave cameras. In addition, motion-detecting software can be utilized to automatically detect, track, and/or zoom in on moving objects.

Claims

1-47. -47. (canceled)

48. A method of automatically expanding the zoom capability of a wide-angle video camera comprising the steps of:

capturing a distorted wide-angle video image using a wide-angle master camera which is capable of extracting a plurality of perspective corrected views under remote PTZ control via a transformation engine within the camera;

remotely controlling a mechanical slave PTZ video camera from said master camera;

transmitting estimated PTZ commands to said slave camera from the master camera to achieve an approximate match between a perspective corrected region of interest view from the master camera and the view from the slave both in direction and size;

routing the digital video output of said slave camera to the said transformation engine in the master camera for reverse transformation into a distorted slave image which is distorted in a similar manner as the distorted wide angle video image;

determining adjustments to said PTZ control signals by comparing said distorted slave image with said distorted wide angle image;

transmitting said PTZ adjustment control signals to said slave camera to obtain a better match between the view from the slave-camera and the perspective corrected view for the said region of interest from the master camera;

further iteratively repeating the previous three steps of this method in order to achieve desired matching accuracy; and

replacing the perspective corrected view of the master camera by the adjusted view from the slave camera so that a remote zoom command for the said region of interest which is outside the zoom range of the master camera may be routed to said slave camera to achieve an expanded optical zoom function.

49. A method as recited in claim 48 wherein said remote PTZ control signals to said master camera are issued locally by a software program resident in the master camera.

50. A method as recited in claim 49 wherein said software program involves motion detection and determines moving regions of the video image.

51. A method as recited in claim 49 wherein said software program involves automatic moving region and object tracking.

52. A method as recited in claim 50 wherein said software program involves automatic moving region and object tracking.

53. A method as recited in claim 48 wherein said estimated PTZ commands are determined by including an adjustment for the relative physical positions of said master and slave cameras.

54. A method as recited in claim 48 wherein said estimated PTZ commands are determined by reference to the pre-designated PTZ presets within the slave camera.

55. A method as recited in claim 48 wherein said slave PTZ camera has an analog video output which needs to be converted into a digital video signal.

56. A method as recited in claim 48 wherein the comparison of said distorted slave image with said distorted wide-angle video image is performed using an image matching technique based on comparing color and wavelet histograms.

57. A method as recited in claim 48 wherein the comparison of said distorted slave image with said distorted wide-angle video image can be performed using a commonly used image comparison measure.

58. A method as recited in claim 57 wherein mean square error is used as said image comparison measure.

59. A method as recited in claim 57 wherein mean absolute difference is used as said image comparison measure.

60. A method as recited in claim 57 wherein color histogram differencing is used as said image comparison measure.

61. A method as recited in claim 48 wherein said replaced perspective corrected image is one of the plurality outputs from the master camera displayed as a separate portion of a multi-view output.

62. A method as recited in claim 48 wherein said replacement has been performed by overlaying.

63. A method as recited in claim 48 wherein the brightness, exposure level, colour balance and other image qualities of said slave camera'"'"'s video output are automatically adjusted by comparing the histograms of the video images from said slave camera to that from said master wide-angle camera.

64. A method of claim 48 wherein the wide-angle camera has a fish eye lens.

65. A method of claim 48 wherein the wide-angle camera has a purpose designed lens to amplify peripheral vision.

66. A method of claim 48 wherein the wide-angle camera has the capability of applying user defined privacy regions to the video output, whether the source video is obtained the camera'"'"'s wide-angle image sensor or the slave camera or both.

67. A method of claim 48 wherein the zoom capability of said wide-angle video camera can be expanded by several slave cameras within the close proximity of the said master camera.

68-90. -90. (canceled)