UnboundLocalError: local variable 'distance' referenced before assignment

抱歉，我在之前的示例代码中犯了一个错误。错误是由于在`detect_objects()`函数中没有正确返回距离和角度导致的。以下是修正后的代码：

#!/usr/bin/env python

import rospy
from std_msgs.msg import Float32
from sensor_msgs.msg import Image
from cv_bridge import CvBridge
import cv2
import numpy as np

def detect_objects(image):
    # Yolov4物体检测逻辑
    # 这里只是一个示例，你需要根据你自己的实际情况进行修改

    # 假设检测到的物体距离为dist，角度为angle
    dist = 3.5
    angle = 45.0

    return dist, angle

def image_callback(msg):
    bridge = CvBridge()
    cv_image = bridge.imgmsg_to_cv2(msg, desired_encoding="passthrough")

    # 对图像进行处理，例如调整大小、转换颜色空间等
    processed_image = cv2.resize(cv_image, (640, 480))
    processed_image = cv2.cvtColor(processed_image, cv2.COLOR_BGR2RGB)

    # 物体检测
    dist, angle = detect_objects(processed_image)

    # 发布距离和角度到ROS话题
    dist_pub.publish(dist)
    angle_pub.publish(angle)

if __name__ == '__main__':
    rospy.init_node('yolov4_object_detection')

    # 创建ROS话题发布者
    dist_pub = rospy.Publisher('object_distance', Float32, queue_size=10)
    angle_pub = rospy.Publisher('object_angle', Float32, queue_size=10)

    # 创建ROS话题订阅者
    image_sub = rospy.Subscriber('image', Image, image_callback)

    rospy.spin()

我已经在`detect_objects()`函数中添加了正确的返回语句来解决`UnboundLocalError`错误。希望这次能够帮助到你！如果还有其他问题，请随时提问。