Imaging apparatus having focus control function

Abstract

A digital camera 1 includes a focus position table. The focus position table, in which focus positions for person-priority pan focus have been set, is used when a face has been detected, and the focus position table (FIG. 2 B), in which focus positions for non-person priority pan focus have been set corresponding to the types of non-person priority pan focus, is used when a face has not been detected. When a face has been detected, the digital camera 1 determines the pan focus as the person-priority pan focus, and after acquiring a focus position from the focus position table, executes the pan focus processing. On the other hand, when a face has not been detected, the digital camera 1 acquires, from the focus position table, a focus position corresponding to a type of non-person priority pan focus determined based on the photography scene and executes the pan focus processing.

1 . An imaging apparatus comprising:
 an imaging section for imaging a photographic subject;   a face detecting section for detecting a human face from an image picked up by the imaging section;   a first focus control section for moving a focus lens to a first lens position when a face has been detected from an image by the face detecting section; and   a second focus control section for moving a focus lens to a second lens position which is different from the first lens position when a face has not been detected from an image by the face detecting section.   
   
   
       2 . The imaging apparatus according to  claim 1 , wherein the face detecting section detects a face which proportion is not less than a predetermined percentage to the whole image picked up by the imaging section. 
   
   
       3 . The imaging apparatus according to  claim 1 , wherein the first focus control section acquires a lens position for person-priority as the first lens position, and moves a focus lens to the acquired lens position for person-priority. 
   
   
       4 . The imaging apparatus according to  claim 1 , wherein the first focus control section acquires, as the first lens position, a lens position corresponding to a size of a face detected from an image by the face detecting section, and moves a focus lens to the acquired lens position. 
   
   
       5 . The imaging apparatus according to  claim 4 , further comprising:
 a number of faces judging section for judging whether multiple faces have been detected from an image by the face detecting section; and   a face identification section for identifying a face which serves as a main photographic subject among the multiple faces when judged by the number of faces judging section that multiple faces have been detected;   wherein the first focus control section acquires, as the first lens position, a lens position corresponding to a size of a single face detected from an image by the face detecting section, when judged by the number of faces judging section that multiple faces have not been detected, and acquires, as the first lens position, a lens position corresponding to a size of a single face which serves as a main photographic subject identified by the face identification section when judged by the number of faces judging section that multiple faces have been detected.   
   
   
       6 . The imaging apparatus according to  claim 5 , wherein the face identification section identifies a face which serves as a main photographic subject based on at least one of requirements consisting of a size of each face, a distance from the center of field angle to each face and a face-likeness of each face detected from an image by the face detecting section. 
   
   
       7 . The imaging apparatus according to  claim 1 , further comprising:
 a photography scene judging section for judging a photography scene;   wherein the second focus control section acquires, as the second lens position, a lens position corresponding to a photography scene judged by the photography scene judging section, and moves a focus lens to the acquired lens position.   
   
   
       8 . The imaging apparatus according to  claim 7 , wherein the photography scene judging section judges a photography scene based on at least one of requirements consisting of whether shooting is with a strobe flash, whether illumination is either one of ultra-high illumination and ultra-low illumination, whether a flicker has been detected, whether a light source is sunlight, and whether an aperture is full. 
   
   
       9 . The imaging apparatus according to  claim 7 , further comprising:
 a determining section for determining a type of pan focus based on a photography scene judged by the photography scene judging section;   wherein the second focus control section acquires, as the second lens position, a lens position corresponding to a type of pan focus determined by the determining section, and moves a focus lens to the acquired lens position.   
   
   
       10 . The imaging apparatus according to  claim 1 , further comprising:
 a zoom magnification setting section for setting a zoom magnification for zoom processing;   wherein the first focus control section acquires, as the first lens position, a lens position corresponding to a zoom magnification set by the zoom magnification setting section, and moves a focus lens to the acquired lens position.   
   
   
       11 . The imaging apparatus according to  claim 1 , further comprising a zoom magnification setting section for setting a zoom magnification for zoom processing;
 wherein the second focus control section acquires, as the second lens position, a lens position corresponding to a zoom magnification set by the zoom magnification setting section, and moves a focus lens to the acquired lens position.   
   
   
       12 . The imaging apparatus according to  claim 1  further comprising:
 a shutter button which enables a half-depression operation and a full-depression operation; and   a first judging section for judging whether the shutter button has been fully depressed without stopping;   wherein the first focus control section moves a focus lens to the first lens position, when judged by the first judging section that a shutter button has been fully depressed without stopping and a face has been detected from an image by the face detecting section, and the second focus control section moves a focus lens to the second lens position when judged by the first judging section that a shutter button has been fully depressed without stopping and a face has not been detected from an image by the face detecting section.   
   
   
       13 . The imaging apparatus according to  claim 12  further comprising:
 an optical zoom magnification setting section for setting an optical zoom magnification for optical zoom; and   an optical zoom magnification judging section for judging whether an optical zoom magnification set by the optical zoom magnification setting section is smaller than a predetermined optical zoom magnification;   wherein the first focus control section moves a focus lens to the first lens position, when judged by the first judging section that a shutter button has been fully depressed without stopping, it is judged by the optical zoom magnification judging section that an optical zoom magnification is smaller than a predetermined optical zoom magnification, and a face has been detected from an image by the face detecting section, and the second focus control section moves a focus lens to the second lens position, when judged by the first judging section that a shutter button has been fully depressed without stopping, it is judged by the optical zoom magnification judging section that an optical zoom magnification is smaller than a predetermined optical zoom magnification, and a face has not been detected from an image by the face detecting section.   
   
   
       14 . The imaging apparatus according to  claim 12  further comprising:
 a second judging section for judging whether the shutter button has been half depressed; and   an auto-focus control section for executing auto-focus processing on a photographic subject;   wherein the auto-focus control section executes the auto-focus processing when judged by the second judging section that a shutter button has been half depressed.   
   
   
       15 . The imaging apparatus according to  claim 14 , further comprising:
 an optical zoom magnification setting section for setting an optical zoom magnification for optical zoom; and   an optical zoom magnification judging section for judging whether an optical zoom magnification set by the optical zoom magnification setting section is smaller than a predetermined optical zoom magnification;   wherein the auto-focus control section further executes the auto-focus processing when judged by the first judging section that a shutter button has been fully depressed without stopping, and judged by the optical zoom magnification judging section that an optical zoom magnification is not smaller than a predetermined optical zoom magnification.   
   
   
       16 . The imaging apparatus according to  claim 14 , wherein the auto-focus control section executes auto-focus processing on an AF area based on a position of a face detected from an image by the face detecting section. 
   
   
       17 . The imaging apparatus according to  claim 16  further comprising:
 a number of faces judging section for judging whether multiple faces have been detected from an image by the face detecting section; and   a face identification section for identifying a face which serves as a main photographic subject among the multiple faces when judged by the number of faces judging section that multiple faces have been detected;   wherein the auto-focus control section executes auto-focus processing on an AF area based on a position of a single face detected from an image by the face detecting section when judged by the number of faces judging section that multiple faces have not been detected, and executes auto-focus processing on an AF area based on a position of a single face which serves as a main photographic subject identified by the face identification section when judged by the number of faces judging section that multiple faces have been detected.   
   
   
       18 . The imaging apparatus according to  claim 14 , wherein the auto-focus control section executes auto-focus processing on an AF area at a predetermined position when a face has not been detected from an image by the face detecting section. 
   
   
       19 . The imaging apparatus according to  claim 14  further comprising:
 an AF failure judging section for judging whether auto-focus processing executed by the auto-focus control section has failed;   wherein the first focus control section moves a focus lens to the first lens position when judged by the AF failure judging section that auto-focus processing has failed and a face has been detected from an image by the face detecting section, and the second focus control section moves a focus lens to the second lens position when judged by the AF failure judging section that auto-focus processing has failed and a face has not been detected from an image by the face detecting section.   
   
   
       20 . The imaging apparatus according to  claim 14 , wherein the first judging section judges that the shutter button has been fully depressed without stopping when the shutter button has been fully depressed before a lapse of predetermined time after a half depression of the shutter button, and the second judging section judges that the shutter button has been half depressed when the predetermined time has passed without the shutter button being fully depressed after a half depression of the shutter button. 
   
   
       21 . The imaging apparatus according to  claim 14 , wherein the first judging section judges that the shutter button has been fully depressed without stopping when judged by the second judging section that the shutter button has been fully depressed without being judged that the shutter button has been half depressed. 
   
   
       22 . The imaging apparatus according to  claim 14  further comprising:
 a third judging section for judging whether the shutter button has been fully depressed when judged by the second judging section that the shutter button has been half depressed;   wherein the first judging section judges that the shutter button has been fully depressed without stopping in the case where auto-focus processing executed by the auto-focus control section is not completed when judged by the third judging section that the shutter button has been fully depressed.   
   
   
       23 . The imaging apparatus according to  claim 1  further comprising:
 an optical zoom magnification setting section for setting an optical zoom magnification for optical zoom; and   an optical zoom magnification judging section for judging whether an optical zoom magnification set by the optical zoom magnification setting section is smaller than a predetermined optical zoom magnification;   wherein the first focus control section moves a focus lens to the first lens position, when judged by the optical zoom magnification judging section that an optical zoom magnification is smaller than a predetermined optical zoom magnification and a face has been detected from an image by the face detecting section, and the second focus control section moves a focus lens to the second lens position when judged by the optical zoom magnification judging section that an optical zoom magnification is smaller than a predetermined optical zoom magnification and a face has not been detected from an image by the face detecting section.   
   
   
       24 . The imaging apparatus according to  claim 23  further comprising:
 an auto-focus control section for executing auto-focus processing on a photographic subject; and   an optical zoom magnification setting section for setting an optical zoom magnification for optical zoom; and   an optical zoom magnification judging section for judging whether an optical zoom magnification set by the optical zoom magnification setting section is smaller than a predetermined optical zoom magnification;   wherein the auto-focus control section executes the auto-focus processing when judged by the optical zoom magnification judging section that an optical zoom magnification is not smaller than a predetermined optical zoom magnification.   
   
   
       25 . A focus control method in an imaging apparatus including an imaging section for imaging a photographic subject, comprising:
 a face detecting step for detecting a human face from an image picked up by the imaging section;   a first focus control step for moving a focus lens to a first lens position when a face has been detected from an image by the face detecting step; and   a second focus control step for moving a focus lens to a second lens position which is different from the first lens position when a face has not been detected from an image by the face detecting step.   
   
   
       26 . A computer-readable storage medium having a program of focus control stored thereon that is executable by a computer for controlling an imaging apparatus including an imaging section for imaging a photographic subject, comprising:
 a face detecting step for detecting a human face from an image picked up by the imaging section;   a first focus control step for moving a focus lens to a first lens position when a face has been detected from an image by the face detecting step; and   a second focus control step for moving a focus lens to a second lens position which is different from the first lens position when a face has not been detected from an image by the face detecting step.