How do I flip (mirror image) an image?

I have an image which is being loaded upside-down and mirrored. So using imrotate, 180 I can have the image the right way around but still mirrored. What function would undo this mirroring?

Thanks

        classdef ROITool < hgsetget
    properties(GetAccess=public, SetAccess=private)        
        FigHandle

        ImageControl
        ScaledImage              
        ImSize

        ROI
        nROI 
        MaxnROIS=100

        ToolBar
        ToolBarItems
        ToolBarSates={'circle','square','ellips','rectangle','line','delete','off'}
        ToolBarImages={'Circle.png','Square.png','Ellips.png','Rectangle.png','line.png','Delete.png','MouseCursor.png'};  

        ROIColors={'blue','green','red','cyan','magenta','yellow'}
    end

    properties (Dependent = true, GetAccess=public, SetAccess = public)
        SelectedType
    end

    methods

        function obj=ROITool(ImageM)   

            if nargin==0
               File='liveimage.jpg';     
               ImageM=double(imread(File));
               ImageM = sum(ImageM, 3) / 3; 
                           end

            %Rescale Image
            ImageM=double(ImageM);
            Rescale=[min(ImageM(:)) max(ImageM(:))-min(ImageM(:))];
            obj.ScaledImage=(ImageM-Rescale(1))./Rescale(2);

            obj.DrawGUI;
            set(obj.ImageControl.imageh, 'UserData',Rescale);
            obj.ImageControl.update(obj.ScaledImage');

            obj.nROI=0;

            X=get(obj.ImageControl.imageh,'XData');
            Y=get(obj.ImageControl.imageh,'YData');
            obj.ImSize=[X(2) Y(2)];

            set(obj.ImageControl.imageh,'ButtonDownFcn',{@obj.Buttondown}); 
            obj.SelectedType='off';
        end

        function obj=Buttondown(obj,handle,~)
            if handle~=obj.ImageControl.imageh;return;end
            Mode=obj.SelectedType;

            cp=get(obj.ImageControl.axesh,'Currentpoint');
            MouseDownPosition=[cp(1,1) cp(1,2)];

            switch lower(Mode)              
                case obj.ToolBarSates(5)                            
                    obj.AddLine(MouseDownPosition);                    
                case obj.ToolBarSates(1:4)                                      
                    obj.AddROI(MouseDownPosition,Mode);                                     
            end            
        end 

        function obj=AddLine(obj,StartPoint)
            if obj.nROI>=obj.MaxnROIS;return;end
            obj.nROI=obj.nROI+1;
            color=obj.ROIColors{mod(obj.nROI,length(obj.ROIColors))+1};

            obj.ROI{obj.nROI}=LineProfile(obj.ImSize,StartPoint,color,obj.nROI,obj.ImageControl.axesh);
            addlistener(obj.ROI{obj.nROI},'DestroyObject',@obj.DeleteROI);
            obj.SelectedType='off';
        end

        function obj=AddROI(obj,centerpoint,Type,radius)
            if obj.nROI>=obj.MaxnROIS;return;end
            if nargin==3;radius=[1 1];end

            obj.nROI=obj.nROI+1;
            color=obj.ROIColors{mod(obj.nROI,length(obj.ROIColors))+1};

            obj.ROI{obj.nROI}=Roi(obj.ImSize,centerpoint,Type,radius,color,obj.nROI,obj.ImageControl.axesh);

            addlistener(obj.ROI{obj.nROI},'DestroyObject',@obj.DeleteROI); 
            obj.SelectedType='off';
        end

        function obj=DeleteROI(obj,~,data)
            obj.nROI=obj.nROI-1;
            for i=data.ROINumber:obj.nROI
                obj.ROI{i}=obj.ROI{i+1};
                obj.ROI{i}.Number=i;
            end 

            obj.SelectedType='off';
        end

        function SType=get.SelectedType(obj)            
            for i=1:length(obj.ToolBarSates)
                State=get(obj.ToolBarItems(i),'State');
                if strcmpi(State,'on');SType=obj.ToolBarSates{i};end                                        
            end

        end

        function set.SelectedType(obj,SType)

            I=find(strcmpi(obj.ToolBarSates,SType));
            if I>length(obj.ToolBarItems);return;end

            State=get(obj.ToolBarItems(I),'State');

            if strcmpi(State,'off') %prevent recursion
                TempCallback=get(obj.ToolBarItems(I),'OnCallback'); 
                set(obj.ToolBarItems(I),'OnCallback','');
                set(obj.ToolBarItems(I),'State','on');
                set(obj.ToolBarItems(I),'OnCallback',TempCallback);
            end

            for i=1:length(obj.ToolBarSates)
                if i~=I;set(obj.ToolBarItems(i),'State','off');end
            end

            if strcmpi(SType,'delete');DeleteFlag=true;else DeleteFlag=false;end

            for i=1:obj.nROI
                obj.ROI{i}.DeleteOnClick=DeleteFlag;
            end

        end

        function obj=SelectDrawMode(obj,~,~,index)            
            obj.SelectedType=obj.ToolBarSates{index};                                                                              
        end

        function obj=DrawGUI(obj)
            Position=[100 50 700 650];
            obj.FigHandle=figure('Position',Position,'ToolBar','none','MenuBar','none','NumberTitle', 'off','Name','ROI and Line Profile Tool for 2D Images');
            obj.ToolBar=uitoolbar;
            obj.ImageControl=imagebox(obj.FigHandle,[50 100 600 500]);

            for i=1:length(obj.ToolBarSates) 
                im=imread(obj.ToolBarImages{i});                
                obj.ToolBarItems(i)=uitoggletool('CData',im,'TooltipString',obj.ToolBarSates{i},'OnCallback',{@obj.SelectDrawMode,i});
            end

        end

    end
end

Answer 1

[Paulo Silva]

after the imrotate do

   set(gca,'xdir','reverse')

Another example

I = imread('onion.png');
I2 = flipdim(I ,2);           %# horizontal flip
I3 = flipdim(I ,1);           %# vertical flip
I4 = flipdim(I3,2);    %# horizontal+vertical flip

subplot(2,2,1), imshow(I)
subplot(2,2,2), imshow(I2)
subplot(2,2,3), imshow(I3)
subplot(2,2,4), imshow(I4)

Reference:flip and rotate a color image in MATLAB

[Colm]

nope, still doesn't work would it be easy if i uploaded the code, it is quite long though?

[Paulo Silva]

should work because it does with this similar example

clf

load clown

imagesc(X)

colormap(map)

pause(2)

set(gca,'xdir','reverse')

[Colm]

its still not working. I've attached the file to my question above

[Colm]

I used ur flip dim to re0write the dicom pixelvalues and it seems to work. thanks

[Bharath Lohray]

Now deprecated. Use `flip` instead of `flipdim`

[Sachin Bisht]

Can someone give me the implementation of mirroring for bitmap images?

Answer 2

[Goku]

To mirror flip an "Image_Original" you can just use flip or rotate and transpose the image :

Image_Flip = flip(Image_Original,2);
Image_Flip = imrotate(Image_Original,90)';

Answer 3

[Thili Mahanama]

From scratch, for a gray scale image

% img=zeros(100,100); % img(50:75,20:35)=1; % img(10:20,10:20)=1;
img=imread('cameraman.tif')
subplot(1,2,1)
imshow(img)
[r,c]=size(img);
imgthili=zeros(100,100);
for i=1:r
	for u=1:c
		if (img(i,u)>=1 )
			imgthili(i,c+1-u)=img(i,u);
		else
			imgthili(i,c+1-u)=img(i,u);
		end
	end
end
subplot(1,2,2)
intth=uint8(imgthili);
imshow(intth)

[Aditi Vedalankar]

Thank Paulo..

It worked..

Regards

Aditi

[Image Analyst]

Yes, but it's not the way you'd do it - with a double for loop. You'd simply do

flippedImage = fliplr(grayImage);

It does the same thing, but more efficiently using a built-in function.

[Stephen23]

Or just using basic indexing:

new = img(:,end:-1:1,:)