OpenCV4 Python 图像旋转 之warpAffine仿射变换参数解释

def rotationImg(img_file1,ra): #ra旋转角度
# 获取图片尺寸并计算图片中心点
    #img = cv2.imread(img_file1, cv2.IMREAD_GRAYSCALE)
    img = np.array(img_file1,dtype=float)
    (h, w) = img.shape[:2]
    center = (w/2, h/2)
    ra=np.random.randint(0,90)
    M = cv2.getRotationMatrix2D(center, ra, 1.0)#第三个参数缩放比例
    rotated = cv2.warpAffine(img, M, (w, h),borderMode=cv2.BORDER_REFLECT)#边界填充模式
    '''
    填充模式参数：
    BORDER_CONSTANT #恒像素值填充
    Python: cv.BORDER_CONSTANT
    iiiiii|abcdefgh|iiiiiii with some specified i

    BORDER_REPLICATE #边界像素值填充
    Python: cv.BORDER_REPLICATE
    aaaaaa|abcdefgh|hhhhhhh

    BORDER_REFLECT #翻转像素值填充
    Python: cv.BORDER_REFLECT
    fedcba|abcdefgh|hgfedcb

    BORDER_WRAP #对称像素值填充
    Python: cv.BORDER_WRAP
    cdefgh|abcdefgh|abcdefg

    BORDER_REFLECT_101 #翻转像素值（去掉边界值）填充
    Python: cv.BORDER_REFLECT_101
    gfedcb|abcdefgh|gfedcba

    BORDER_TRANSPARENT #透明填充
    Python: cv.BORDER_TRANSPAREN
    '''
    #cv2.imshow("rotated", rotated)
    #cv2.waitKey(0)
    #cv2.imwrite(out_file, rotated)

    return rotated