Hi everyone,
I'm a beginner and trying to use the basic OpenCV to find the choose color ball's center x,y value from the image. But When I try to run my program there had some error happen but I had no idea what's wrong in my program. Can anyone help me?
Follow is my progam:
#!/usr/bin/env python
# coding=utf-8
import sys
import rospy
import cv2
import cv
import argparse
import numpy as np
from std_msgs.msg import String
from sensor_msgs.msg import Image
import std_srvs.srv
def image_processing (color):
#image_src = cv2.imread('home/ros_ws/src/baxter_examples/ColorBalls.jpg',0)
print ("deciding color...............")
if color == "blue":
lower = (86,31,4)
upper = (220,88,50)
if color == "green":
lower = (29,86,6)
upper = (64,255,255)
if color == "red":
lower = (17,15,100)
upper = (50,56,200)
print color
image_hsv = cv2.cvtColor(image_src,cv2.COLOR_BGR2HSV)##################
image_mask = cv2.inRange(image_hsv,lower,upper)
image_mask = cv2.erode(image_mask, None, iterations=2)
image_mask = cv2.dilate(image_mask, None, iterations=2)
print ("end maskingg")
print ("finding center.........")
contours,hierarchy = cv2.findContours(image_mask,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)[-2]
if len(contours) > 0:
c = max (contours,key=cv2.contourArea)
((x, y), radius) = cv2.minEnclosingCircle(c)
M = cv2.moments(c)
center = (int(M["m10"] / M["m00"]), int(M["m01"] / M["m00"]))
print center
if radius > 1:
cv2.circle(image_src, (int(x), int(y)), int(radius),(0, 255, 255), 2)
cv2.circle(image_src, center, 2, (0, 0, 255), -1)
def main():
global ball_color
global image_src
arg_fmt = argparse.RawDescriptionHelpFormatter
parser = argparse.ArgumentParser(formatter_class=arg_fmt, description=main.__doc__)
parser.add_argument(
'-c','---color', dest='color',choices=['blue','green','red'], required=True,
help= "the ball color to pick up",
)
args=parser.parse_args()
print ("Initializing...........................................")
rospy.init_node("ylj_ballposition",anonymous=True)
image_src = cv2.imread('home/ros_ws/src/baxter_examples/ColorBalls.jpg',1)
image_processing(args.color)
cv2.imshow("image_processed",image_src)
if __name__=='__main__':
main()
This is the error message show:
Initializing...........................................
deciding color...............
blue
OpenCV Error: Assertion failed ((scn == 3 || scn == 4) && (depth == CV_8U || depth == CV_32F)) in cvtColor, file /build/buildd/opencv-2.4.8+dfsg1/modules/imgproc/src/color.cpp, line 3959
Traceback (most recent call last):
File "/home/leddar/ros_ws/src/baxter_examples/scripts/ylj/ylj_imgball.py", line 101, in
main()
File "/home/leddar/ros_ws/src/baxter_examples/scripts/ylj/ylj_imgball.py", line 91, in main
image_processing(args.color)
File "/home/leddar/ros_ws/src/baxter_examples/scripts/ylj/ylj_imgball.py", line 36, in image_processing
image_hsv = cv2.cvtColor(image_src,cv2.COLOR_BGR2HSV)##################
cv2.error: /build/buildd/opencv-2.4.8+dfsg1/modules/imgproc/src/color.cpp:3959: error: (-215) (scn == 3 || scn == 4) && (depth == CV_8U || depth == CV_32F) in function cvtColor
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