import numpy as np
import cv2
cap = cv2.VideoCapture(0)

while (True):
    ret, frame = cap.read()    
    params = cv2.SimpleBlobDetector_Params()    
    params.minThreshold = 10;     # Change thresholds
    params.maxThreshold = 300;
    params.filterByColor = True    # Filter by color.    
    params.blobColor = 255  # 0 for darkblobs - 255 for light blobs)
    params.filterByArea = True    # Filter by Area.
    params.minArea = 100
    params.maxArea = 600 
    detector = cv2.SimpleBlobDetector_create(params)
    keypoints = detector.detect(frame)    
    im_with_keypoints = cv2.drawKeypoints(frame, keypoints, np.array([]), (0,0,255), cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS)    
    cv2.imshow('frame', im_with_keypoints)
    for kp in keypoints:
     print (int(kp.pt[0]), int(kp.pt[1]))
    
    if cv2.waitKey(1) == 27:
        break