程序执行提示UnboundLocalError: local variable 'thresh' referenced before assignment，优化程序def deal_threshold(image): gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) _, binary_image = cv2.threshold(gray, 127, 255, cv2.THRESH_BINARY) binary_image[binary_image == 255] = 1 edges = cv2.Canny(image, 50, 150) lines = cv2.HoughLines(edges, 1, np.pi / 180, threshold=90) sumang = 0 count = 0 if lines is not None: for line in lines: anglep = line[0][1] * 180 / np.pi if anglep > 90: anglep = 180 - anglep sumang += anglep count += 1 angle = sumang / count thresh = Image.fromarray(gray).rotate(angle) thresh = cv2.cvtColor(np.asarray(thresh), cv2.COLOR_BGR2GRAY) return thresh def process_images(input_folder, output_folder): os.makedirs(output_folder, exist_ok=True) images = [] output_paths = [] for filename in os.listdir(input_folder): if filename.endswith(".jpg") or filename.endswith(".png"): image_path = os.path.join(input_folder, filename) images.append(cv2.imread(image_path)) output_paths.append(os.path.join(output_folder, filename)) for image, output_path in zip(images, output_paths): thresh = deal_threshold(image)

在 `process_images` 函数中，`thresh` 变量在循环中被赋值，但在循环结束后使用之前没有被声明。这导致了 `UnboundLocalError` 错误。为了解决这个问题，可以在循环开始之前将 `thresh` 变量初始化为 `None`，然后在循环结束后检查它是否被赋值，并根据需要处理它。以下是优化后的代码示例：

def process_images(input_folder, output_folder):
    os.makedirs(output_folder, exist_ok=True)
    images = []
    output_paths = []
    for filename in os.listdir(input_folder):
        if filename.endswith(".jpg") or filename.endswith(".png"):
            image_path = os.path.join(input_folder, filename)
            images.append(cv2.imread(image_path))
            output_paths.append(os.path.join(output_folder, filename))

    thresh = None  # 初始化 thresh 变量
    for image, output_path in zip(images, output_paths):
        new_thresh = deal_threshold(image)
        if new_thresh is not None:
            thresh = new_thresh

    if thresh is not None:
        # 在这里处理 thresh 变量
        # 例如保存到文件或进行其他操作
        pass

在优化后的代码中，我们在循环开始之前初始化 `thresh` 变量为 `None`。然后，在每次迭代中将 `deal_threshold` 的结果赋值给 `new_thresh`。如果 `new_thresh` 不是 `None`，则将其赋值给 `thresh`。最后，我们在循环结束后检查 `thresh` 是否被赋值，并根据需要进行进一步处理。