Point cloud missing points after running ros_to_pcl

[chaonan99]

I tried to convert ROS point cloud to pcl format using ros_to_pcl under Exercise-2/sensor_stick/scripts/pcl_helper.py and show the result in rviz. The original point cloud looks like this:

After ros_to_pcl and pcl_to_ros, lots of points are missing,

And if I remove skip_nans=True in ros_to_pcl, the color becomes strange,

Is this a problem with read_points function or caused by some problems in my code? Here is my code for republishing the topic:

import rospy
from sensor_msgs.msg import PointCloud2
from pcl_helper import ros_to_pcl, pcl_to_ros

def publisher(pc):
  pcl_data = ros_to_pcl(pc)
  ros_pc = pcl_to_ros(pcl_data)
  pub.publish(ros_pc)
  rospy.loginfo("Publish to /repub_pc")
  rate.sleep()

rospy.init_node('pcl_test', anonymous=True)
rospy.Subscriber('/camera/depth_registered/points', PointCloud2, publisher,
    queue_size=10,  buff_size=2**30)

rate = rospy.Rate(float(5))
pub = rospy.Publisher('/repub_pc', PointCloud2, queue_size=10)
rospy.spin()