image_proc

#!/usr/bin/env python

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

help = """Usage: python image_proc --in=/image_raw/ --out=/camera/image_raw/

-i, --in: topic to extract the video stream. Default: /image_raw/
-o, --out: topic to publish the video stream. Default: /camera/image_raw/
-b, --brightness: brightness increase. Default: 30
-c, --contrast: contrast coefficient. Default: 1
"""

inTopic = '/image_raw'
outTopic = '/camera/image_raw'
brightness = 10
contrast = 1

bridge = CvBridge()
rospy.init_node('image_proc', anonymous=True)
pub = rospy.Publisher(outTopic, Image, queue_size=10) # Offboard control

try:
    opts, _ = getopt.getopt(sys.argv[1:],'hi:o:b:c:',['help', 'in=', 'out=', 'brightness=', 'contrast='])
except getopt.GetoptError:
    print(help)
    sys.exit(2)

for opt, arg in opts:
    if opt in ('-h', '--help'):
        print(help)
        sys.exit()
    elif opt in ('-i', '--in'):
        inTopic = arg
    elif opt in ('-o', '--out'):
        outTopic = arg
    elif opt in ('-b', '--brightness'):
        brightness = int(arg)
    elif opt in ('-c', '--contrast'):
        contrast = float(arg)

def image_callback(img_msg):
    try:
        cv_image = bridge.imgmsg_to_cv2(img_msg, "bgr8")
    except CvBridgeError as e:
        rospy.logerr("CvBridge Error: {}".format(e))

    cv_image = cv.convertScaleAbs(cv_image, alpha=contrast, beta=brightness)

    # Histogram egalization
    # cv_image = cv.cvtColor(cv_image, cv.COLOR_BGR2GRAY);
    # cv_image = cv.equalizeHist(cv_image)
    # cv_image = cv.cvtColor(cv_image, cv.COLOR_GRAY2RGB)

    try:
        image_message = bridge.cv2_to_imgmsg(cv_image, encoding="bgr8")
        pub.publish(image_message)
    except CvBridgeError as e:
        rospy.logerr("CvBridge Error: {}".format(e))


sub_image = rospy.Subscriber(inTopic, Image, image_callback)

rospy.loginfo('Image processing stream started...')
while not rospy.is_shutdown():
    rospy.spin()