I get a error when using HoughCircles with Python OpenCV that a module is missing [duplicate]

Answer 1

add this line : import cv2.cv as cv and change circles

circles = cv2.HoughCircles(gray,cv.CV_HOUGH_GRADIENT)

i.e. cv.CV_HOUGH_GRADIENT in place of cv2.CV_HOUGH_GRADIENT

This will solve the AttributeError that you were getting but still you'll get a type error, you'll have to provide arguments for dp and minDist (arguments at pos 3 and pos 4) and that you can give accordingly.(Here I've given 1 and 10)

#!/usr/local/bin/python
import cv2
import cv2.cv as cv
import numpy as np

img = cv2.imread("test.jpg")
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
circles = cv2.HoughCircles(gray,cv.CV_HOUGH_GRADIENT, 1, 10)

also please see a similar problem solved here:

http://answers.opencv.org/question/1497/errors-with-cv2houghcircles/

Answer 2

try

circles = cv2.HoughCircles(gray, cv2.cv.CV_HOUGH_GRADIENT, 1.2, 75)

works, to me