issues with displaying video of drone

[Arsalan66]

Prerequisites

Please answer the following questions for yourself before submitting an issue. YOU MAY DELETE THE PREREQUISITES SECTION.

• [x] I am running the latest version of GAAS
• [no answer ] I checked the Gitbook documentation and found no answer
• [ i checked all resources] I checked to make sure that this issue has not already been filed
• [ i have searched a lot] I Googled/Binged the error messages generated by Ubuntu, Gazebo, and PX4
• [ only one forum] I have posted questions regarding Ubuntu, Gazebo, and PX4 in corresponding forums.

Issue Template

Context

Please provide any relevant information about your setup.

• Tutorial No.:[all]
• Mavros: [eg. 0.18.4]
• ROS: [ melodic]
• Gazebo: [ 7]
• Ubuntu: [eg. 18.04]
• System Platform: [ X86]

Expected Behavior

Please describe the behavior you are expecting. I want to process videos based on drone's camera

Current Behavior

What is the current behavior? I have created a publisher and subscriber to video frames on a custom video and it runs perfectly however when i subscribe to topics related to camera, it doesn't show up anything although my program says that frames are being received

Screenshots

If applicable, add screenshots to help explain your problem. here's a screenshot which runs my code here's the output of custom video

Failure Logs

this is the topic that i subscribe to for drone, it says frames are being recieved but doesn't show anything i made a custom drone:

Copy console log and paste it here.

[Arsalan66]

what are the steps that i'm doing wrong and what can i do to rectify them?

[Doodle1106]

I do not think the problem is related to this repo.

If you are sure callbacks are executed, you can add some print functions to help you debug, I don't quite see any issue in the code you provided.

[Arsalan66]

Thanks for the kind response basically I want to implement IBVS via colour detection schemes suppose if I do this in GAAS framework, what are the subscribers that I would have to keep in mind to manipulate the camera, I'll be grateful for your kind response

[Arsalan66]

i ALSO usec cv2.imshow to check

[hddgi]

Can you confirm that you have published information by using the “rostopic” command? Or can you display your published Image msg in ”rviz“?

[Arsalan66]

i made a custom publisher but in case of manipulating the drone's camera i'm unsure about the subscribers

[Arsalan66]

sir can i have your mail, i want to discuss this small issue with you

[hddgi]

We prefer to answer questions at GitHub issue, This can help other people with the same problem.

I don't see any issue in the code you provided. So if you can provide the message you printed using the rostopic command or the rviz screenshot will help me determine the problem.

You can see the usage about rostopic and rviz in GAAS tutorial 1 and GAAS tutorial 2.

[Arsalan66]

Ok sir , I'll provide as soon as possible , thanks for the kind response

[Arsalan66]

!/usr/bin/env python

import rospy, cv2

from std_msgs.msg import String

import numpy as np from sensor_msgs.msg import Image from cv_bridge import CvBridge, CvBridgeError

bridge = CvBridge() def tracking_ball(mask,cv_image):

create a black image

black_image = np.zeros(cv_image.shape, np.uint8)
_,contours,_ = cv2.findContours(mask,cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)
for c in contours:
    if cv2.contourArea(c) > 1000:
        # find radius
        ((x,y),r) = cv2.minEnclosingCircle(c)
        # find the cx, cy of the contour
        m = cv2.moments(c)
        cx = -1
        cy = -1
        if m['m00'] != 0:
            cx = int(m['m10']/m['m00'])
            cy = int(m['m01']/m['m00'])
        # draw the contours
        cv2.drawContours(cv_image,[c],-1,(0,0,255),1)
        cv2.drawContours(black_image,[c],-1,(0,0,255),1)
        # draw a circle around the ball
        cv2.circle(cv_image,(cx,cy),int(r),(255,0,0),1)
        cv2.circle(black_image,(cx,cy), int(r),(255,0,0),1)
        # draw the center of the ball
        cv2.circle(cv_image,(cx,cy),5,(0,0,0),-1)
        cv2.circle(black_image,(cx,cy),5,(0,0,0),-1)
        # show images
        #img_join = np.concatenate((cv_image,black_image),axis=1)
        cv2.imshow('cv_image', cv_image)
        cv2.imshow('black_image',black_image)

def create_mask(hsv_image): lower_hsv = (30,100,100) upper_hsv = (50,255,255) mask = cv2.inRange(hsv_image,lower_hsv,upper_hsv) return mask

def hi_callback(ros_image): print 'got an image' global bridge cv_image = bridge.imgmsg_to_cv2(ros_image, "bgr8") hsv = cv2.cvtColor(cv_image,cv2.COLOR_BGR2HSV) mask=create_mask(hsv) tracking_ball(mask,cv_image) rospy.loginfo('frame received!') cv2.waitKey(5)

if name == 'main':

# create a node
rospy.init_node('tennis_ball_listener_node',anonymous=True)
# create the subscriber
rospy.Subscriber('/gi/simulation/left/image_raw',Image,hi_callback)
# start a loop
rospy.spin()

@hddgi sir, this is my code , i want to process video published by '/gi/simulation/left/image_raw' topic, however the output was the same that frames are being received but not shown, what might i be doing wrong?

[Arsalan66]

Sir, another method that i have in mind is to manipulate the publisher, where might be it's file located and is it a good idea or not?

[Arsalan66]

here's the publisher that i used for testing

!/usr/bin/env python

import numpy as np import cv2 from std_msgs.msg import String from sensor_msgs.msg import Image import rospy import sys from cv_bridge import CvBridge, CvBridgeError

bridge = CvBridge()

def talker(): pub = rospy.Publisher('tennis_ball_image', Image, queue_size=10) rospy.init_node('talker', anonymous=True)

1hz

video_capture = cv2.VideoCapture('video/tennis-ball-video.mp4')
rate = rospy.Rate(1)

while not rospy.is_shutdown():
    # read a frame
    ret, frame = video_capture.read()
    #frame = cv2.resize(frame,None,fx=0.25,fy=0.25,interpolation=cv2.INTER_CUBIC)
    if ret:
        # publish frame in data
        frame_msg = bridge.cv2_to_imgmsg(frame,'bgr8')
        pub.publish(frame_msg)
        rospy.loginfo('Sending frame')
        rate.sleep()

video_capture.release()
cv2.destroyAllWindows()

if name == 'main': try: talker() except rospy.ROSInterruptException: pass