cv2对图像进行旋转和放缩变换

旋转：

def get_image_rotation(image):
    #通用写法，即使传入的是三通道图片依然不会出错
    height, width = image.shape[:2]
    center = (width // 2, height // 2)
    rotation = random.randint(-20,20)

    #得到旋转矩阵，第一个参数为旋转中心，第二个参数为旋转角度，第三个参数为旋转之前原图像缩放比例
    M = cv2.getRotationMatrix2D(center, -rotation, 0.7)
    #进行仿射变换，第一个参数图像，第二个参数是旋转矩阵，第三个参数是变换之后的图像大小
    image_rotation = cv2.warpAffine(image, M, (width, height))
    return image_rotation

缩放：

#得到缩放后的图片
def get_image_scale(image):
    height, width = image.shape[:2]

    width_random = random.randint(-3, 3)
    width_scale = 1.0 + width_random / 10.0
    height_random=random.randint(1,6)
    height_scale=1.0+height_random/10.0

    #print("width_scale:%f,height_scale:%f" %(width_scale,height_scale))

    image_resize = cv2.resize(image, (int(width_scale * width), int(height)), interpolation=cv2.INTER_CUBIC)
    height_resize,width_resize=image_resize.shape
    #print('image_binary height: %d width :%d' %(height,width))
    #print('image_scale height: %d  %d' %(height_resize,width_resize))
    return image_resize