Image capture apparatus and method for tracking a subject

Abstract

Disclosed is an image capture apparatus that has a subject tracking functionality of sequentially detecting a predetermined subject in images that are continuously shot, and a method for controlling the same. During tracking of the subject, degrees of reliability of tracking are determined. When the detected face is set as a template image, the template image is not changed until it is determined a predetermined plurality of times in succession that the degrees of reliability of tracking are low. It is thus possible to achieve a subject tracking functionality that is hardly affected by false detections.

1 . (canceled) 
     
     
         2 . An image capture apparatus comprising:
 a face detection unit configured to detect a face that is included in an image;   a subject detecting unit configured to track a subject by sequentially detecting an area, which has information similar to specific information of the subject, in a sequence of images obtained by shooting, wherein the specific information includes brightness information and/or color information; and   a control unit configured to:
 if information obtained from a face detected by the face detection unit has been set as the specific information,
 not change the specific information until it is determined that the subject detection unit has lost the subject, and 
 change the specific information to information obtained from a subject that meets a predetermined condition if (i) it is determined that the subject detection unit has lost the subject and (ii) there is a subject that meets the predetermined condition. 
 
   
     
     
         3 . The image capture apparatus according to  claim 2 , further comprising:
 an image sensor configured to generate the image; and   a transmissive member configured to display a focus area frame,   wherein the subject detecting unit tracks the subject in a sequence of images generated by the image sensor from light received through the transmissive member.   
     
     
         4 . The image capture apparatus according to  claim 2 , wherein the control unit determines that the subject detecting unit has lost the subject if reliability of detection by the subject detecting unit is less than a predetermined value for a predetermined plurality of times in succession. 
     
     
         5 . The image capture apparatus according to  claim 4 , wherein the subject that meets the predetermined condition is a face that has been continuously detected for the predetermined plurality of times in succession. 
     
     
         6 . The image capture apparatus according to  claim 2 , further comprising:
 an automatic exposure control unit configured to control an exposure amount based on a brightness value of a plurality of faces detected by the face detection unit.   
     
     
         7 . The image capture apparatus according to  claim 3 , further comprising:
 an autofocus control unit configured to select one of a plurality of the focus area frames based on a location of the subject tracked by the subject detecting unit.   
     
     
         8 . An image capture apparatus comprising:
 a face detection unit configured to detect a face that is included in an image;   a subject detecting unit configured to track a subject by sequentially detecting an area, which has information similar to specific information of the subject, in a sequence of images obtained by shooting, wherein the specific information includes brightness information and/or color information; and   a control unit configured to:
 if information obtained from a face detected by the face detection unit has been set as the specific information,
 not change the specific information until it is determined that the subject detection unit has lost the subject, and 
 temporarily interrupt tracking of the subject using the specific information if (i) it is determined that the subject detection unit has lost the subject and (ii) there is no subject that meets a predetermined condition. 
 
   
     
     
         9 . The image capture apparatus according to  claim 8 , further comprising:
 an image sensor configured to generate the image; and   a transmissive member configured to display a focus area frame,   wherein the subject detecting unit tracks the subject in a sequence of images generated by the image sensor from light received through the transmissive member.   
     
     
         10 . The image capture apparatus according to  claim 8 , wherein the control unit determines that the subject detecting unit has lost the subject if reliability of detection by the subject detecting unit is less than a predetermined value for a predetermined plurality of times in succession. 
     
     
         11 . The image capture apparatus according to  claim 10 , wherein the subject that meets the predetermined condition is a face that has been continuously detected for the predetermined plurality of times in succession. 
     
     
         12 . The image capture apparatus according to  claim 8 , further comprising:
 an automatic exposure control unit configured to control an exposure amount based on a brightness value of a plurality of faces detected by the face detection unit.   
     
     
         13 . The image capture apparatus according to  claim 9 , further comprising:
 an autofocus control unit configured to select one of a plurality of the focus area frames based on a location of the subject tracked by the subject detecting unit.   
     
     
         14 . An image capture apparatus comprising:
 a transmissive member configured to display a focus area frame;   an image sensor configured to generate an image from light received through the transmissive member;   a face detection unit configured to detect a face that is included in the image;   a subject detecting unit configured to track a subject by sequentially detecting an area, which has information similar to specific information of the subject, in a sequence of images generated by the image sensor, wherein the specific information includes brightness information and/or color information; and   a control unit configured to:
 if information obtained from a face detected by the face detection unit has been set as the specific information,
 not change the specific information until it is determined that the subject detection unit has lost the subject. 
 
   
     
     
         15 . The image capture apparatus according to  claim 14 , further comprising:
 an automatic exposure control unit configured to control an exposure amount based on a brightness value of a plurality of faces detected by the face detection unit.   
     
     
         16 . The image capture apparatus according to  claim 14 , further comprising:
 an autofocus control unit configured to select one of a plurality of the focus area frames based on a location of the subject tracked by the subject detecting unit.   
     
     
         17 . A method for controlling an image capture apparatus, wherein the image capture apparatus includes a face detection unit configured to detect a face that is included in an image, and a subject detecting unit configured to track a subject by sequentially detecting an area, which has information similar to specific information of the subject, in a sequence of images obtained by shooting, wherein the specific information includes brightness information and/or color information, the method comprising:
 if information obtained from a face detected by the face detection unit has been set as the specific information:
 not changing the specific information until it is determined that the subject detection unit has lost the subject, and 
 changing the specific information to information obtained from a subject that meets a predetermined condition if (i) it is determined that the subject detection unit has lost the subject and (ii) there is a subject that meets the predetermined condition. 
   
     
     
         18 . A method for controlling an image capture apparatus, wherein the image capture apparatus includes a face detection unit configured to detect a face that is included in an image, and a subject detecting unit configured to track a subject by sequentially detecting an area, which has information similar to specific information of the subject, in a sequence of images obtained by shooting, wherein the specific information includes brightness information and/or color information, the method comprising:
 if information obtained from a face detected by the face detection unit has been set as the specific information:
 not changing the specific information until it is determined that the subject detection unit has lost the subject, and 
 temporarily interrupting tracking of the subject using the specific information if (i) it is determined that the subject detection unit has lost the subject and (ii) there is no subject that meets a predetermined condition. 
   
     
     
         19 . A method for controlling an image capture apparatus, wherein the image capture apparatus includes:
 a transmissive member configured to display a focus area frame;   an image sensor configured to generate an image from light received through the transmissive member;   a face detection unit configured to detect a face that is included in the image; and   a subject detecting unit configured to track a subject by sequentially detecting an area, which has information similar to specific information of the subject, in a sequence of images generated by the image sensor, wherein the specific information includes brightness information and/or color information, the method comprising:
 if information obtained from a face detected by the face detection unit has been set as the specific information:
 not changing the specific information until it is determined that the subject detection unit has lost the subject.