Hi, i am dooing the openCV for robotics course. if i use the code from exercise 2.2 and i rosrun the python file, the cv2.imwrite function works correctly, but if i run the launch file the imwrite function will not save the jpg.
Here is my exemple code:
#!/usr/bin/env python
import rospy
from sensor_msgs.msg import Image
from cv_bridge import CvBridge, CvBridgeError
import cv2
import time
class Test_image(object):
def __init__(self):
self.image_sub = rospy.Subscriber("/camera/rgb/image_raw", Image, self.camera_calback)
self.image_path = '/home/user/catkin_ws/src/opencv_for_robotics_images/Unit_2/Course_images/test_image_1.jpg'
self.cv_bridge_object = CvBridge()
self.cv_image = cv2.imread(self.image_path)
self.ctr_c = False
rospy.on_shutdown(self.shutdownhook)
def read_and_show_image(self):
try:
img = cv2.imread(self.image_path)
except CvBridgeError as e:
print(e)
cv2.imshow("name of an image: ZIGA", img)
cv2.waitKey(0)
drone_image = cv2.imwrite('drone_image.jpg', self.cv_image)
try:
cv2.destroyAllWindows()
print("destroyed in camera call back")
except:
print("soeomthing went wrong with the destroying images")
def camera_calback(self, data):
try:
self.cv_image = self.cv_bridge_object.imgmsg_to_cv2(data, desired_encoding="bgr8")
except CvBridgeError as e:
print (e)
def imwrite(self):
rospy.loginfo("writing image to file")
cv2.imshow("name of an image: ZIGA displayed image", self.cv_image)
cv2.waitKey(0)
drone_image = cv2.imwrite('imafdsdvgfsdfsge.jpg', self.cv_image)
print(drone_image)
try:
cv2.destroyAllWindows()
print("destroyed the windows")
except:
print("soeomthing went wrong with the destroying images")
def shutdownhook(self):
rospy.loginfo("Robot shutting down")
self.ctr_c = True
def main():
rospy.init_node("test_node")
open_cv_class = Test_image()
#open_cv_class.read_and_show_image()
print("executing imwrite function")
#time.sleep(2)
open_cv_class.imwrite()
while not rospy.is_shutdown():
rospy.spin()
if __name__ == '__main__':
main()
print("Ros is shutting down")
and here is the launch file:
<launch>
<node pkg="unit2" name="load_image_node" type="load_image.py" output="screen"/>
</launch>
any ideas why this could be?
thanks Ziga
