opencv-python 几个小案例记录

旋转图片

def rotate_image(image_path, angle, scale=1.0):
    # 读取图像
    image = cv2.imread(image_path)

    if image is None:
        print("Error: Could not read the image.")
        return None

    # 获取图像的高度和宽度
    (h, w) = image.shape[:2]

    # 计算图像中心
    center = (w / 2, h / 2)

    # 生成旋转矩阵
    M = cv2.getRotationMatrix2D(center, angle, scale)

    # 执行仿射变换
    rotated = cv2.warpAffine(image, M, (w, h))

    return rotated

裁切圆形

def crop_circle(image_path):
    # 读取图像
    image = cv2.imread(image_path)

    if image is None:
        print("Error: Could not read the image.")
        return None

    # 获取图像的高度和宽度
    (h, w) = image.shape[:2]

    # 计算圆的中心 和 半径
    center_x, center_y = w // 2, h // 2
    radius = min(center_x, center_y)

    # 创建一个掩膜，初始全黑（零）
    mask = np.zeros((h, w), dtype="uint8")

    # 在掩膜上绘制白色圆圈
    cv2.circle(mask, (center_x, center_y), radius, 255, -1)

    # 通过掩膜应用图像
    masked_image = cv2.bitwise_and(image, image, mask=mask)

    # 为了去除多余的黑色部分，将结果放入新的最小矩形中
    x = center_x - radius
    y = center_y - radius
    cropped_image = masked_image[y:y + 2 * radius, x:x + 2 * radius]

    return cropped_image

待续...