How can i slip and rotate a color image?

Question

Carole 2012-11-28

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Hi,how can i slip and rotate the color image img like the binary image bw?

I=imread('image.jpg'); %color image
bw=segmentation(I); % the result is a binary image where the object detected (ROI) is white
img = bsxfun(@times, I, cast(bw,class(I)));
phy = regionprops(bw, 'Orientation')
[barx,bary]=barycentre(edge);
% slip the region to the center of the image
edge = recentre(edge,barx,bary);
I2 = recentre(bw,barx,bary);
phy1=phy.Orientation;
edge=imrotate(edge,-phy,'loose');
I3=imrotate(I2,-phy,'loose');

thanks

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Carole 2012-11-28

The function recenter and imrotate work with the binary image bw where the ROI is centred and rotated very well but when i want to center and rotate the ROI of the color image img it doesn't work :( . I couldn't use imtransform to center the region and rotate the image with a given angle -phy

yagnesh 2012-11-29

use imrotate after separating rgb planes and after that combine those 3 planes

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Answer 1

Image Analyst 2012-11-29

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Have you tried circshift() to slide the image over?

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Image Analyst 2012-11-29

编辑：Image Analyst 2012-11-30

在 MATLAB Online 中打开

Try this code as an example:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables.
workspace;  % Make sure the workspace panel is showing.
format longg;
format compact;
fontSize = 20;
% Read in a standard MATLAB color demo image.
folder = fullfile(matlabroot, '\toolbox\images\imdemos');
baseFileName = 'onion.png';
% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);
if ~exist(fullFileName, 'file')
  % Didn't find it there.  Check the search path for it.
  fullFileName = baseFileName; % No path this time.
  if ~exist(fullFileName, 'file')
    % Still didn't find it.  Alert user.
    errorMessage = sprintf('Error: %s does not exist.', fullFileName);
    uiwait(warndlg(errorMessage));
    return;
  end
end
rgbImage = imread(fullFileName);
% Get the dimensions of the image.  numberOfColorBands should be = 3.
[rows columns numberOfColorBands] = size(rgbImage);
% Display the original color image.
subplot(2, 2, 1);
imshow(rgbImage, []);
axis on;
title('Original Color Image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Ask the user to click the point they want to be at the center.
userPrompt = 'Click the point you want to be at the center';
promptMessage = sprintf('Click the point you want to be at the center,\nor Cancel to abort processing?');
titleBarCaption = 'Continue?';
button = questdlg(promptMessage, titleBarCaption, 'Continue', 'Cancel', 'Continue');
if strcmp(button, 'Cancel')
  return;
end
[x, y] = ginput(1)
% Determine the middle of the picture.
middleX = columns/2
middleY = rows/2
deltaX = fix(middleX - x)
deltaY = fix(middleY - y)
% Use circshift to shift the image.
% Move white onion to the middle of the image.
shiftsize = [deltaY deltaX 0]
shiftedImage = circshift(rgbImage, shiftsize);
subplot(2, 2, 2);
imshow(shiftedImage, []);
title('Shifted Color Image', 'FontSize', fontSize);
impixelinfo();
axis on;

Carole 2012-12-1

thanks it works with some modifications knowing that I want to move the centroid of the object to the center of the image

Image Analyst 2012-12-1

OK great. Go ahead and mark it as "Answered" then.

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Answer 2

Sean de Wolski 2012-11-28

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在 MATLAB Online 中打开

imrotate can rotate color images just fine:

imshow(imrotate(imread('peppers.png'),42,'crop'))

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Carole 2012-11-29

在 MATLAB Online 中打开

It seems that the problem is in the function recentre because it works with the binary image bw but it doesn't work with the color image img

I=imread('image.jpg'); %color image
bw=segmentation(I); % the result is a binary image where the object detected (ROI) is white
img = bsxfun(@times, I, cast(bw,class(I)));
edge2 = edge(bw, 'prewitt');
edge2 = 1 - edge2;
[barx,bary]=barycentre(edge2);
edge2 = recentre(edge2,barx,bary);
I2 = recentre(bw,barx,bary);
I3 = recentre(img,barx,bary);

The function

function im_trans=recentre(image,barx,bary)
[X,Y]=size(image);
tx=floor(X/2)-barx;
ty=floor(Y/2)-bary;
im_trans = zeros(X, Y);
if tx>=0
    if ty>=0
        for i=1 : X-tx
            for j=1 : Y-ty
                im_trans(i+tx, j+ty) = image(i, j);
            end
        end
    elseif ty<0
        for i=1 : X-tx
            for j=abs(ty)+1 : Y
                im_trans(i+tx, j+ty) = image(i, j);
            end
        end
    end
elseif tx<0
    if ty>=0
        for i=abs(tx)+1 : X
            for j=1 : Y-ty
                im_trans(i+tx, j+ty) = image(i, j);
            end
        end
    elseif ty<0
        for i=abs(tx)+1 : X
            for j=abs(ty)+1 : Y
                im_trans(i+tx, j+ty) = image(i, j);
            end
        end
    end
end
can you help me to correct it please