How to rotate MRI image in python code example
Example 1: rotate image python
import skimage
import skimage.transform
rotated_img=skimage.transform.rotate(img,-60, resize=True)
Example 2: how to rotate image python manually
def rotate_image(img, degrees, output_scale="crop"):
assert output_scale in ["crop", "full"], "output_scale should be either 'crop' or 'full'"
rot_rad = degrees * np.pi / 180.0
rotate_m = np.array([[np.cos(rot_rad), np.sin(rot_rad)],
[- np.sin(rot_rad), np.cos(rot_rad)]])
gray_scale = False
if len(img.shape) < 3:
img = img.reshape(*img.shape, 1)
gray_scale = True
h, w, c = img.shape
if output_scale == "full":
diagonal = int(np.sqrt(h * h + w * w))
im_padded = np.zeros((diagonal, diagonal, c))
center_h = int((diagonal - h) // 2)
center_w = int((diagonal - w) // 2)
im_padded[center_h:-center_h, center_w:-center_w, :] = img
img = im_padded
rotated_image = np.zeros((diagonal, diagonal, c))
h, w, c = img.shape
else:
rotated_image = np.zeros((h, w, c))
indices_org = np.array(np.meshgrid(np.arange(h), np.arange(w))).reshape(2, -1)
indices_new = indices_org.copy()
indices_new = np.dot(rotate_m, indices_new).astype(int)
mu1 = np.mean(indices_new, axis=1).astype(int).reshape((-1, 1))
mu2 = np.mean(indices_org, axis=1).astype(int).reshape((-1, 1))
indices_new += (mu2-mu1)
t0, t1 = indices_new
t0 = (0 <= t0) & (t0 < h)
t1 = (0 <= t1) & (t1 < w)
valid = t0 & t1
indices_new = indices_new.T[valid].T
indices_org = indices_org.T[valid].T
xind, yind = indices_new
xi, yi = indices_org
rotated_image[xi, yi, :] = img[xind, yind, :]
if gray_scale:
rotated_image = rotated_image.reshape((h, w))
return rotated_image.astype(np.uint8)
img = cv2.imread(image_path)
rotated = rotate_image(img, 45)
cv2.imshow("Rotated_Image", rotated)
cv2.waitkey(0)