Autofocus initialization based on target detection

Abstract

One or more depth sensors are configured to acquire one or more depth measurements associated with at least one object. One or more orientation sensors are configured to determine orientation information of an imaging device based on orientation information of an optical device of the imaging device. An object distance between the imaging device and one of the at least one object is estimated based on the one or more depth measurements and the orientation information of the imaging device. The optical device is moved from a first position to a second position according to the object distance and focal information of the optical device, and is moved from the second position to a third position according to an autofocus operation.

What is claimed is: 
     
         1 . A focusing method comprising:
 acquiring, by one or more depth sensors, one or more depth measurements associated with at least one object;   determining, by one or more orientation sensors, orientation information of an imaging device based on orientation information of an optical device of the imaging device, the imaging device capturing one of the at least one object;   estimating an object distance between the imaging device and the one of the at least one object based on the one or more depth measurements and the orientation information of the imaging device;   moving the optical device from a first position to a second position according to the object distance and focal information of the optical device; and   moving the optical device from the second position to a third position according to an autofocus operation.   
     
     
         2 . The method of  claim 1 , wherein the autofocus operation comprises a contrast autofocus operation. 
     
     
         3 . The method of  claim 1 , wherein one of the one or more depth sensors has an orientation along one direction in a space, and one of the one or more depth measurements includes depth information indicative of a projection of the object distance on the direction. 
     
     
         4 . The method of  claim 3 , wherein acquiring, by the one or more depth sensors, the one or more depth measurements comprises:
 generating, by a signal generator, a signal; and   detecting, by the one or more depth sensors, a reflection signal of the signal from the at least one object along the direction of the one or the one or more depth sensors.   
     
     
         5 . The method of  claim 1 , wherein the orientation information of the imaging device indicates an orientation of a center axis of the optical device with respect to at least one direction in a space. 
     
     
         6 . The method of  claim 5 , wherein the one or more depth sensors comprise at least one of:
 a first depth sensor that has a first orientation along a first axis of a coordinate system, the coordinate system including a Cartesian coordinate system;   a second depth sensor that has a second orientation along a second axis of the coordinate system; or   a third depth sensor that has a third orientation along a third axis of the coordinate system.   
     
     
         7 . The method of  claim 6 , wherein the orientation information of the imaging device is indicative of:
 a first angle between the center axis of the optical device and the first axis; and   a second angle based on the first angle and a third angle between the center axis of the optical device and the second axis.   
     
     
         8 . The method of  claim 6 , wherein estimating the object distance between the imaging device and the one of the at least one object comprises:
 determining, using the orientation information of the imaging device, a first angle between the center axis of the optical device and the first axis;   determining, using the orientation information of the imaging device, a second angle between:
 a projection of the center axis of the optical device on a plane defined by the second axis and the third axis, and 
 the second axis; and 
   estimating the object distance based on the first angle, the second angle, and the one or more depth measurements.   
     
     
         9 . An unmanned aerial vehicle (UAV) comprising:
 a propulsion system;   an imaging device comprising an optical device;   one or more depth sensors configured to acquire one or more depth measurements associated with at least one object;   one or more orientation sensors configured to determine orientation information of the imaging device based on orientation information of the optical device, the imaging device capturing one of the at least one object; and   one or more processors coupled to the propulsion system, the one or more depth sensors, the one or more orientation sensors, and the imaging device, and configured to:
 estimate an object distance between the imaging device and the one of the at least one object based on the one or more depth measurements and the orientation information of the imaging device; 
 control the optical device to move from a first position to a second position according to the object distance and focal information of the optical device; and 
 control the optical device to move from the second position to a third position according to an autofocus operation. 
   
     
     
         10 . The UAV of  claim 9 , wherein the autofocus operation comprises a contrast autofocus operation. 
     
     
         11 . The UAV of  claim 9 , wherein one of the one or more depth sensors has an orientation along one direction in a space, and one of the one or more depth measurements includes depth information indicative of a projection of the object distance on the direction. 
     
     
         12 . The UAV of  claim 11 , wherein the one or more depth sensors are configured to acquire the one or more depth measurements by detecting a reflection signal of a signal from the at least one object along the direction of the one of the one or more depth sensors, the signal being generated by a signal generator. 
     
     
         13 . The UAV of  claim 9 , wherein the orientation information of the imaging device indicates an orientation of a center axis of the optical device with respect to at least one direction in a space. 
     
     
         14 . The UAV of  claim 13 , wherein the one or more depth sensors comprise at least one of:
 a first depth sensor that has a first orientation along a first axis of a coordinate system, the coordinate system including a Cartesian coordinate system;   a second depth sensor that has a second orientation along a second axis of the coordinate system; and   a third depth sensor that has a third orientation along a third axis of the coordinate system.   
     
     
         15 . The UAV of  claim 14 , wherein the orientation information of the imaging device is indicative of:
 a first angle between the center axis of the optical device and the first axis; and   a second angle based on the first angle and a third angle between the center axis of the optical device and the second axis.   
     
     
         16 . The UAV of  claim 14 , wherein the one or more processors are configured to estimate the object distance between the imaging device and the one of the at least one object by:
 determining, using the orientation information of the imaging device, a first angle between the center axis of the optical device and the first axis;   determining, using the orientation information of the imaging device, a second angle between:
 a projection of the center axis of the optical device on a plane defined by the second axis and the third axis, and 
 the second axis; and 
   estimating the object distance based on the first angle, the second angle, and the one or more depth measurements.   
     
     
         17 . The UAV of  claim 9 , wherein the one or more depth sensors comprise at least one of a pressure sensor, an infrared sensor, an ultrasonic sensor, a stereo camera, or a time-of-flight camera. 
     
     
         18 . The UAV of  claim 9 , wherein the one or more orientation sensors comprise at least one of an accelerometer, a magnetometer, a potentiometer, a Hall sensor, or a gyroscope. 
     
     
         19 . A focusing system, comprising:
 one or more depth sensors configured to acquire one or more depth measurements associated with at least one object;   one or more orientation sensors configured to determine orientation information of an imaging device based on orientation information of an optical device of the imaging device, the imaging device capturing one of the at least one object; and   one or more processors coupled to the one or more depth sensors, the one or more orientation sensors, and the imaging device, and configured to:
 estimate an object distance between the imaging device and the one of the at least one object based on the one or more depth measurements and the orientation information of the imaging device; 
 control the optical device to move from a first position to a second position according to the object distance and focal information of the optical device; and 
 control the optical device to move from the second position to a third position according to an autofocus operation. 
   
     
     
         20 . The system of  claim 19 , wherein the autofocus operation comprises a contrast autofocus operation.