extractSubImage

3334 단어
function [new_img,crop,obj_location]=extractSubImage(img,box,crop_margin)
% extractSubImage - extracts the face from an image with a margin
% if the margin goes beyond the image, the last pixel will be continued
%
% Syntax:  [new_img,crop,obj_location]=extractSubImage(img,box,crop_margin)
%
% Inputs:
%    img - image (i.e. load with imread)
%    box - location of face (i.e. img(box(2):box(4),box(1):box(3),:))
%    crop_margin - margin around face as a fraction of the width, height
%                  [left above right below], default is [0.4 0.4 0.4 0.4]
%
% Outputs:
%    new_img - cropped face with margin
%    crop - coordinates in original image of the cropped region
%    obj_location - coordinates in cropped image of the cropped region
%
% Example:
% Getting all faces of the wikipedia dataset with default margin:
% load('wiki/wiki.mat');
% for i=1:length(wiki.dob)
%    fprintf('Cropping face %d/%d
',i,length(wiki.dob)); % orig_img=imread(['wiki/' wiki.full_path{i}]); % cropped_face{i}=extractSubImage(orig_img,wiki.face_location{i}); % end % % Author: Rasmus Rothe % Address: Sternwartstrasse 7, 8092 Zurich, Switzerland % email: [email protected] % Website: http://www.vision.ee.ethz.ch % Jan 2016; Last revision: 16-Jan-2016 % set default margin if nargin==2 crop_margin=[0.4 0.4 0.4 0.4]; end % size of face orig_size(1)=box(4)-box(2)+1; orig_size(2)=box(3)-box(1)+1; % add margin full_crop(1)=round(box(1)-crop_margin(1).*orig_size(2)); full_crop(2)=round(box(2)-crop_margin(2).*orig_size(1)); full_crop(3)=round(box(3)+crop_margin(3).*orig_size(2)); full_crop(4)=round(box(4)+crop_margin(4).*orig_size(1)); % size of face with margin new_size(1)=full_crop(4)-full_crop(2)+1; new_size(2)=full_crop(3)-full_crop(1)+1; % ensure that the region cropped from the original image with margin % doesn't go beyond the image size crop(1)=max(full_crop(1),1); crop(2)=max(full_crop(2),1); crop(3)=min(full_crop(3),size(img,2)); crop(4)=min(full_crop(4),size(img,1)); % size of the actual region being cropped from the original image crop_size(1)=crop(4)-crop(2)+1; crop_size(2)=crop(3)-crop(1)+1; % create new image new_img=single(zeros(new_size(1),new_size(2),size(img,3))); % coordinates of region taken out of the original image in the new image new_location(1)=crop(1)-full_crop(1)+1; new_location(2)=crop(2)-full_crop(2)+1; new_location(3)=crop(1)-full_crop(1)+crop_size(2); new_location(4)=crop(2)-full_crop(2)+crop_size(1); % coordinates of the face in the new image obj_location(1)=new_location(1)+box(1)-crop(1)+1; obj_location(2)=new_location(2)+box(2)-crop(2)+1; obj_location(3)=new_location(3)+box(3)-crop(3)+1; obj_location(4)=new_location(4)+box(4)-crop(4)+1; % do the crop new_img(new_location(2):new_location(4),new_location(1):new_location(3),:)=... img(crop(2):crop(4),crop(1):crop(3),:); % if margin goes beyond the size of the image, repeat last row of pixels if new_location(2)>1 new_img(1:new_location(2)-1,:,:)=repmat(new_img(new_location(2),:,:),[new_location(2)-1,1,]); end if new_location(4)1 new_img(:,1:new_location(1)-1,:)=repmat(new_img(:,new_location(1),:),[1,new_location(1)-1,1]); end if new_location(3)

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