OpenCV Python HoughCircles error
- by Dan
Hi,
I'm working on a program that detects circular shapes in images. I decided a Hough Transform would be the best, and I found one in the OpenCV library. The problem is that when I try to use it I get an error that I have no idea how to fix. Is OpenCV for Python not fully implemented? Is there a fix to the library I need for the program to work?
Here's the code:
import cv
#cv.NamedWindow("camera", 1)
capture = cv.CaptureFromCAM(0)
while True:
img = cv.QueryFrame(capture)
gray = cv.CreateImage(cv.GetSize(img), 8, 1)
edges = cv.CreateImage(cv.GetSize(img), 8, 1)
cv.CvtColor(img, gray, cv.CV_BGR2GRAY)
cv.Canny(gray, edges, 50, 200, 3)
cv.Smooth(gray, gray, cv.CV_GAUSSIAN, 9, 9)
storage = cv.CreateMat(1, 2, cv.CV_32FC3)
#This is the line that throws the error
cv.HoughCircles(edges, storage, cv.CV_HOUGH_GRADIENT, 2, gray.height/4, 200, 100)
#cv.ShowImage("camera", img)
if cv.WaitKey(10) == 27:
break
And here is the error I'm getting:
OpenCV Error: Null pinter () in unknown function,
file ..\..\..\..\ocv\openc\src\cxcore\cxdatastructs.cpp, line 408
Traceback (most recent call last):
File "ellipse-detect-webcam.py", line 20, in
cv.HoughCircles(edges, storage, cv.CV_HOUGH_GRADIENT, 2, gray.height/4, 200, 100)
cv.error
Thanks in advance for the help.
