Image pick-up apparatus and tracking method therefor

Abstract

An image pick-up apparatus that enables to appropriately set a holding time in which there is a possibility of returning to a state that allows tracking when a subject cannot be tracked temporarily during the subject tracking to improve the ease-of-use for a user. A specifying unit specifies a subject included in a captured image. A display unit displays the captured image on a screen and displays identification information showing that the specified subject is tracked. A tracking unit tracks the subject. A setting unit sets a holding time in which the display of the identification information is held according to at least one of a focal length of the image pick-up apparatus and a subject distance. An elimination unit eliminates a display of the identification information when the holding time has passed after the tracking unit lost the subject.

1 . An image pick-up apparatus that generates captured images in series, comprising:
 a tracking unit adapted to track a specified subject by extracting a region of the specified subject in the presently generated captured image having high correlation with a region of the specified subject in the precedently generated captured image;   a display unit adapted to display the captured image on a screen and display identification information showing that the specified subject is tracked; and   a setting unit adapted to set a holding time in which the display of the identification information is held,   wherein said display unit continues to display the identification information when the holding time does not lapse after said tracking unit lost the subject, and eliminates a display of the identification information when the holding time has passed after said tracking unit lost the subject, and   wherein said setting unit changes the holding time according to a sensitivity and at least one of control information for an image stabilizer and an output from an angle velocity sensor of the image pick-up apparatus.   
     
     
         2 . The image pick-up apparatus according to  claim 1 , wherein said setting unit sets the shorter holding time when it is determined that the image pick-up apparatus shakes according to at least one of the control information and the output from the angle velocity sensor, as compared with the holding time when the image pick-up apparatus does not shake. 
     
     
         3 . The image pick-up apparatus according to  claim 1 , wherein said setting unit sets the holding time according to the position at which the subject tracking has failed in the field of the captured image. 
     
     
         4 . The image pick-up apparatus according to  claim 3 , wherein said setting unit sets the shorter holding time as the distance between the position at which the subject tracking has failed and a center of the field of the captured image becomes larger. 
     
     
         5 . A tracking method for an image pick-up apparatus that generates captured images in series; said method comprising:
 a tracking step of the image pick-up apparatus tracking a specified subject by extracting a region of the specified subject in the presently generated captured image having high correlation with a region of the specified subject in the precedently generated captured image;   a display step of the image pick-up apparatus displaying the captured image on a screen and display identification information showing that the specified subject is tracked; and   a setting step of the image pick-up apparatus setting a holding time in which the display of the identification information is held,   wherein said display step continues to display the identification information when the holding time does not lapse after said tracking step lost the subject, and eliminates a display of the identification information when the holding time has passed after the subject has been lost in said tracking step, and   wherein said setting step changes the holding time according to a sensitivity and at least one of control information for an image stabilizer and an output from an angle velocity sensor of the image pick-up apparatus.