n06_pytorch_utils.py 文件源码

def randomShiftScaleRotate(img, shift_limit=0.0625, scale_limit=0.1, rotate_limit=45, u=0.5):
    if random.random() < u:
        height, width, channel = img.shape

        angle = random.uniform(-rotate_limit, rotate_limit)  # degree
        scale = random.uniform(1 - scale_limit, 1 + scale_limit)
        dx = round(random.uniform(-shift_limit, shift_limit)) * width
        dy = round(random.uniform(-shift_limit, shift_limit)) * height

        cc = math.cos(angle / 180 * math.pi) * (scale)
        ss = math.sin(angle / 180 * math.pi) * (scale)
        rotate_matrix = np.array([[cc, -ss], [ss, cc]])

        box0 = np.array([[0, 0], [width, 0], [width, height], [0, height], ])
        box1 = box0 - np.array([width / 2, height / 2])
        box1 = np.dot(box1, rotate_matrix.T) + np.array([width / 2 + dx, height / 2 + dy])

        box0 = box0.astype(np.float32)
        box1 = box1.astype(np.float32)
        mat = cv2.getPerspectiveTransform(box0, box1)
        img = cv2.warpPerspective(img, mat, (width, height), flags=cv2.INTER_LINEAR,
                                  borderMode=cv2.BORDER_REFLECT_101)  # cv2.BORDER_CONSTANT, borderValue = (0, 0, 0))  #cv2.BORDER_REFLECT_101

    return img