Method of detecting specific object region and digital camera

A digital camera for pickup of a picture frame, comprising:

• an image sensor for sequentially creating picture frames by picking up an object sequentially;
• an input unit for acquiring a shift amount between a present picture frame presently created among said picture frames and a previous picture frame created prior to said present picture frame among said picture frames;
• a normalizer for shifting an outline frame defined around said previous picture frame according to said shift amount on said previous picture frame, to form a normalized picture frame from an image region surrounded in said outline frame after shifting;
• a difference region detector for retrieving a difference between said present picture frame and said normalized picture frame, to detect a difference region according to said difference and included in said present picture frame;
• a specific object detector for detecting a specific object region in said difference region by searching said specific object region in said difference region, said searching being performed by shifting a detection region in said difference region and said detecting of the specific object region being performed on all of said sequentially created picture frames.

A detecting method of detecting a specific object region located in a picture frame recorded by an image sensor, comprising steps of:

• sequentially creating picture frames by picking up an object sequentially;
• acquiring a magnification change of magnification between a present picture frame presently created among said picture frames and a previous picture frame created prior to said present picture frame among said picture frames;
• zooming an outline frame defined around said previous picture frame with a coefficient equal to a reciprocal of said magnification change so as to create a zoomed outline frame, and zooming said previous picture frame with a coefficient equal to said magnification change, to obtain a normalized picture frame surrounded in said zoomed outline frame;
• retrieving a difference between said present picture frame and said normalized picture frame, to detect a difference region according to said difference and included in said present picture frame;
• detecting said specific object region in said difference region by searching said specific object region in said difference region, said searching being performed by shifting a detection region in said difference region,
• wherein if there is a lack of said difference region in said difference region detection for said present picture frame, said information of said specific object region obtained for said previous picture frame is used for said present picture frame;
• wherein pattern matching of image recognition is used in detecting said specific object region from said difference region;
• and
• wherein said specific object region is a human facial image region;
• and
• wherein the step of detecting said specific object region is performed on all of said sequentially created picture frames.

A digital camera for pickup of a picture frame, comprising:

• an image sensor for sequentially creating picture frames by picking up an object sequentially;
• an input unit for acquiring a magnification change of magnification between a present picture frame presently created among said picture frames and a previous picture frame created prior to said present picture frame among said picture frames;
• a normalizer for zooming an outline frame defined around said previous picture frame with a coefficient equal to a reciprocal of said magnification change so as to create a zoomed outline frame, and zooming said previous picture frame with a coefficient equal to said magnification change, to obtain said normalized picture frame surrounded in said zoomed outline frame;
• a difference region detector for retrieving a difference between said present picture frame and said normalized picture frame, to detect a difference region according to said difference and included in said present picture frame;
• a specific object detector for detecting a specific object region in said difference region by searching said specific object region in said difference region, said searching being performed by shifting a detection region in said difference region, wherein said detecting of the specific object region is performed on all of said sequentially created picture frames.