tfi.py 文件源码

def affine_zoom( img, zoom, spin = 0 ):
    '''Returns new image derived from img, after a central-origin affine transform has been applied'''
    img_copy = img.copy()

    # Shift transforms allow Affine to be applied with centre of image as 0,0
    shift_y, shift_x, _ = (np.array(img_copy.shape)-1) / 2.
    shift_fwd = transform.SimilarityTransform(translation=[-shift_x, -shift_y])
    shift_back = transform.SimilarityTransform(translation=[shift_x, shift_y])
    affine = transform.AffineTransform( scale=(zoom, zoom), rotation=(spin * math.pi/180) )

    img_copy = transform.warp( img_copy,
                     ( shift_fwd + ( affine + shift_back )).inverse,
                     order=3,
                     clip=False, preserve_range=True,
                     mode='reflect').astype(np.float32)
    return img_copy