Darker Edges

Captured Image

Last week my friend was in need of her signature in digital format. Fortunately, it was not for any official purpose. So we captured the signature using the camera and used it.

The image that we acquired using the camera was not that much good. So we processed the image and then included in the document.

After this thing happened, I thought of trying the image with MATLAB.

First I adjusted the image intensity using the imadjust function . 
The syntax for the imadjust for rgb image is

imadjust(RGB,[Low_R Low_G Low_B; High_R High G High B],[]);

The Low values should always be lower than High values.

The range of these values between 0 to 1.

After Imadjust

Then I detected the edge of the image. Then to enlarge the image parts I dilated it. Use an appropriate structure element. Here I used 'disk'.

After that, using labeling method, I labeled all the connected components. Based on the size of the components the components where finally used and components whose size are less are ignored.

Edge detected Image

MATLAB CODE:

function my_edge

global filename A I ;

scz=get(0,'ScreenSize');

figure('Position',[round(scz(1,3)/4) round(scz(1,4)/8) 700 500],'MenuBar','None','NumberTitle','off','Name','Pencil sketch Application','Resize','off');

axes('Position',[0 0 .7 1],'xtick',[],'ytick',[]);

Low=uicontrol('Style','slider','Position',[500,280 200 20],'Max',0.99 ,'Min',0,'Value',0.0,'SliderStep',[0.05,0.1],'Callback',@draw);

High=uicontrol('Style','slider','Position',[500,370 200 20],'Max',1,'Min',0.1,'Value',.5,'SliderStep',[0.05,0.1],'Callback',@draw);

uicontrol('Style','pushbutton','String','Done','Position',[500 200 40 20],'Callback',@pushme);

directory=dir('*.jpg');

files={directory.name}';

uicontrol('style','text','Position',[500,310 100 20]','String','Low:');

uicontrol('style','text','Position',[500,395 100 20]','String','High :');

uicontrol('style','text','Position',[500,455 100 20]','String','Filename:');

uicontrol('Style','popupmenu','position',[500 420 160 30],'Value',1,'String',files,'Callback',@displayfile);



    function displayfile(obj,eve)

        ptr=get(obj,'value');

        filename=char(files(ptr));

        A=imread(filename);

        A=imresize(A,0.4);

        subplot('Position',[0.05 0.1 .6 .9]);imshow(A);

    end



    function draw(obj,eve)

        H=get(High,'Value');

        L=get(Low,'Value');

      uicontrol('Style','edit','position',[500 250 50 20],'String',L);

      uicontrol('Style','edit','position',[500 340 50 20],'String',H);

        if( L < H )


            %The intensity values for each R,G,B planes are adjusted.

            I=imadjust(A,[L L L; H H H],[]);

        end

           subplot('Position',[0.05 0.1 .6 .9]);imshow(I);

       end





                                                                                                         

                                                                                        

                                                                                         

                                                                                   

                                                                                    












































    function pushme(obj,eve)

        myedges(I);

    end

    function myedges(A)

      

A1=rgb2gray(A);



B=(edge(A(:,:,1))|edge(A(:,:,2))|edge(A(:,:,3)));

Edge detected

SE=strel('disk',3);

C=~(imdilate(B,SE));





target=(ones([size(A1,1) size(A1,2)] ));

[BW,label]=bwlabel(~C,8);



for l=1:max(max(label))

[row, col] = find(BW==l);



if(size(row,1)>30)



for i=1:size(row,1)

    x=row(i,1);

    y=col(i,1);

    target(x,y)=C(x,y);

end

end



end

subplot('Position',[0 0.5 .8 .45]);imshow(A);title('Original Image');

subplot('Position',[0 0   .8 .45]);imshow(target);title('Final Image');









    end

end

Another example:

After Imadjust and edge detection (structuring element:disk Radius=1)