Imaging system and method

Abstract

A baseline adjustment method includes acquiring a first image of an object by a first imaging device of an imaging apparatus, acquiring a second image of the object by a second imaging device of the imaging apparatus, determining a binocular disparity between the first and second image and determining an object distance based at least on the binocular disparity by the controller, and automatically adjusting a baseline according to the object distance by a baseline adjustment mechanism. The object distance represents a distance between the imaging apparatus and the object. The baseline represents a relative distance between the first and second imaging device. The baseline is being adjusted to fall within a range approximately between a minimum and a maximum baseline. The maximum baseline is defined by the object distance and an angle-of-view of at least one of the first or the second imaging device.

What is claimed is: 
     
         1 . A method for baseline adjustment of an imaging apparatus, comprising:
 acquiring, by a first imaging device of the imaging apparatus, a first image of an object;   acquiring, by a second imaging device of the imaging apparatus, a second image of the object;   determining, by a controller, a binocular disparity between the first image and the second image;   determining, by the controller, an object distance based at least on the binocular disparity, the object distance representing a distance between the imaging apparatus and the object; and   automatically adjusting, by a baseline adjustment mechanism, a baseline according to the object distance, the baseline representing a relative distance between the first imaging device and the second imaging device,   wherein the baseline is being adjusted to fall within a range approximately between a minimum baseline and a maximum baseline, and wherein the maximum baseline is defined by the object distance and an angle-of-view of at least one of the first imaging device or the second imaging device.   
     
     
         2 . The method of  claim 1 , wherein the maximum baseline is Z* tan(Θ/2), and wherein Z is the object distance and Θ is the angle-of-view of the at least one of the first imaging device or the second imaging device. 
     
     
         3 . The method of  claim 1 , wherein automatically adjusting the baseline further comprises:
 decreasing the baseline in response to determining that the baseline is greater than the maximum baseline by a tolerance.   
     
     
         4 . The method of  claim 1 , wherein the minimum baseline is defined by the object distance, a pixel width of at least one of the first imaging device or the second imaging device, and a focal length of the at least one of the first imaging device or the second imaging device. 
     
     
         5 . The method of  claim 4 , wherein the minimum baseline is 4*Z*L/f, and wherein Z is the object distance, L is the pixel width of the at least one of the first imaging device or the second imaging device, and f is the focal length of the at least one of the first imaging device or the second imaging device. 
     
     
         6 . The method of  claim 1 , wherein automatically adjusting the baseline further comprises:
 increasing the baseline in response to determining that the baseline is below the minimum baseline by a tolerance.   
     
     
         7 . The method of  claim 1 , wherein the imaging apparatus is further coupled to an unmanned aerial vehicle (UAV), and wherein automatically adjusting the baseline further comprises:
 adjusting the baseline according to an operational mode of the UAV.   
     
     
         8 . The method of  claim 7 , wherein the operational mode includes at least one of a landing mode, a takeoff mode, or an aerial image acquisition mode, wherein the baseline is decreased in response to determining that the operational mode is the landing mode, and wherein the baseline is increased in response to determining that the operation mode is the takeoff mode or the aerial image acquisition mode. 
     
     
         9 . The method of  claim 1 , wherein determining the object distance comprises:
 selecting one or more feature points on the object;   determining one or more feature distances between the imaging apparatus and the one or more feature points based at least on the binocular disparity for each feature point on the first image and the second image; and   determining the object distance using the one or more feature distances.   
     
     
         10 . The method of  claim 9 , wherein determining the object distance comprises averaging the one or more feature distances. 
     
     
         11 . The method of  claim 9 ,
 wherein selecting the one or more feature points comprises selecting a predetermined percentage of feature points that are adjacent to the imaging apparatus; and   wherein determining the object distance comprises determining the object distance as the feature distance of one of the selected feature points that is farthest from the imaging apparatus.   
     
     
         12 . The method of  claim 9 , wherein determining the one or more feature distances between the imaging apparatus and the one or more feature points comprises:
 determining the one or more feature distances based on pixels corresponding to the one or more feature points on the first image acquired by the first imaging device or the second image acquired by the second imaging device.   
     
     
         13 . The method of  claim 1 , further comprising:
 calibrating extrinsic parameters of the imaging apparatus after automatically adjusting the baseline, wherein the extrinsic parameters comprise at least one of a translational extrinsic parameter or a rotational extrinsic parameter.   
     
     
         14 . The method of  claim 1 , wherein a first optical axis of the first imaging device is parallel to a second optical axis of the second imaging device. 
     
     
         15 . An imaging system, comprising:
 a first imaging device configured to acquire a first image of an object;   a second imaging device configured to acquire a second image of the object;   a controller configured to:
 determine a binocular disparity between the first image and the second image; 
 determine an object distance based at least on the binocular disparity, the object distance representing a distance between the imaging system and the object; and 
 generate control signals based on the object distance for automatically adjusting a baseline, the baseline representing a relative distance between the first imaging device and the second imaging device; and 
   a baseline adjustment mechanism coupled with the first imaging device and the second imaging device, the baseline adjustment mechanism being in communication with the controller and configured to adjust the baseline according to the control signals received from the controller,   wherein the baseline is being adjusted to fall within a range approximately between a minimum baseline and a maximum baseline, and wherein the maximum baseline is defined by the object distance and an angle-of-view of at least one of the first imaging device or the second imaging device.   
     
     
         16 . The imaging system of  claim 15 , wherein the maximum baseline is Z*tan(Θ/2), and wherein Z is the object distance and Θ is the angle-of-view of the at least one of the first imaging device or the second imaging device. 
     
     
         17 . The imaging system of  claim 15 , wherein the minimum baseline is defined by the object distance, a pixel width of at least one of the first imaging device or the second imaging device, and a focal length of the at least one of the first imaging device or the second imaging device. 
     
     
         18 . An imaging apparatus, comprising:
 a first imaging device configured to acquire a first image of an object;   a second imaging device configured to acquire a second image of the object; and   a baseline adjustment mechanism coupled with the first imaging device and the second imaging device and configured to automatically adjust a baseline according to an object distance, the object distance representing a distance between the imaging apparatus and the object and the baseline representing a relative distance between the first imaging device and the second imaging device,   wherein the object distance is determined based at least on a binocular disparity between the first image and the second image, and   wherein the baseline is being adjusted to fall within a range approximately between a minimum baseline and a maximum baseline, and wherein the maximum baseline is defined by the object distance and an angle-of-view of at least one of the first imaging device or the second imaging device.   
     
     
         19 . The imaging apparatus of  claim 18 , wherein the maximum baseline is Z*tan(Θ/2), and wherein Z is the object distance and Θ is the angle-of-view of the at least one of the first imaging device or the second imaging device. 
     
     
         20 . The imaging apparatus of  claim 18 , wherein the minimum baseline is defined by the object distance, a pixel width of at least one of the first imaging device or the second imaging device, and a focal length of the at least one of the first imaging device or the second imaging device.