CompressImage、Image传输时出现size=0的情况!_acdbrasterimage imagesize为0

def capture_image(self, ret, image) -> CompressedImage:
 
if ret:
 
    obj_cimage = CompressedImage()
 
    obj_head = Header()
 
 
    obj_head.frame_id = "camera"
 
    obj_head.stamp = rospy.Time.now()
 
    obj_head.seq = 0
 
    # 编码图像为PNG格式的二进制数据
 
    retval, buffer = cv2.imencode('.png', image)
 
    if retval:
 
        obj_cimage.data = np.array(buffer).tobytes()
 
        obj_cimage.format = "png"
 
        obj_cimage.header = obj_head
 
        return obj_cimage
 
    else:
 
        rospy.logerr("图像编码失败")
 
else:
 
    rospy.logerr("没有摄像头数据")

cvbridge=CvBridge()
 
class Sub_image():
    def __init__(self) -> None:
         self.image_sub=rospy.Subscriber("/cam_image",CompressedImage,self.showcb,queue_size=1)
    def showcb(self,data):
        cv_image=cvbridge.compressed_imgmsg_to_cv2(data,"bgr8")
        cv2.imshow("dd",cv_image)
        cv2.waitKey(1)
 
def main():
    rospy.init_node("test1",anonymous=True)
    # 实例化的时候自动就会执行init
    sub_obj=Sub_image()
    rospy.spin()

可以将图像通过cv2.imencode编码一下，就可以了，具体原因不知道为什么。。