MATLAB: Problem with output of imrotate function.

Question

Hi, after using imrotate function, why center of object is changing. this problem is appear by obtain center of object before and after rotation. please guide me how to rotate image without changing coordination of center's object. original image:

output after rotation:

    clc;clear;
    img = imread('ms0.jpg');
    degree = 45;
    img1 = imrotate(img,-degree,'crop');
    prob1 = regionprops(img,'centroid');
    prob2 = regionprops(img1,'centroid');
    img_center = prob1.Centroid;
    img1_center = prob2.Centroid;
    img_center = round(img_center);
    img1_center = round(img1_center);
    fprintf('center before  rotation is : ( %d , %d ) \n.',img_center(1),img_center(2));
    fprintf('center after rotation is : ( %d , %d ) \n.',img1_center(1),img1_center(2));

Answer 1

imrotate() rotates about the center of the center of the image. Your blob is not at the center of the image so it will move. Perhaps you should crop your image if you want it to be at the center of an image.