calcOpticalFlowPyrLK丟失單個跟蹤點

我想寫一個python程序來跟蹤用戶的頭部運動，基於他們眼睛之間的單點。我正在使用OpenCV 2.4.5和calcOpticalFlowPyrLK。我使用HAAR點設置了初始點，並且初始點是正確的，但是在第一次調用calcOpticalFlowPyrLK之後，程序正在跟蹤完全不同的點。我對計算機視覺並不是很熟悉，所以我無法弄清楚爲什麼它失去了初始點。calcOpticalFlowPyrLK丟失單個跟蹤點

我使用python 2.7，Fedora 18和OpenCV 2.4.5。

我的代碼：

import numpy as np 
import cv2 

cap = cv2.VideoCapture(0) 

# loading the classifiers 
hcf = cv2.CascadeClassifier('/usr/share/OpenCV/haarcascades/haarcascade_frontalface_default.xml') 
hce = cv2.CascadeClassifier('/usr/share/OpenCV/haarcascades/haarcascade_eye.xml') 

# params for ShiTomasi corner detection 
feature_params = dict(maxCorners = 100, 
         qualityLevel = 0.3, 
         minDistance = 7, 
         blockSize = 7) 

# Parameters for lucas kanade optical flow 
lk_params = dict(winSize = (15,15), 
        maxLevel = 2, 
        criteria = (cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, 10, 0.03)) 

# Create some random colors 
color = np.random.randint(0,255,(100,3)) 

# Take first frame and find corners in it 
ret, old_frame = cap.read() 
old_gray = cv2.cvtColor(old_frame, cv2.COLOR_BGR2GRAY) 

# Create a mask image for drawing purposes 
mask = np.zeros_like(old_frame) 

first = True 
while(1): 
    #Get new frame 
    ret,frame = cap.read() 
    frame_gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) 

    #First iteration, calcualte the face 
    if(first): 
     first = False 
     faces = hcf.detectMultiScale(frame_gray, minSize=(100, 100)) 
     face = faces[0] 
     print face[0],face[1],face[2],face[3] 

     p0 = [[((face[0] + (face[2]/2)),(face[1] + (face[3]/3)))]] 
     p0 = np.float32(np.asarray(p0)) 
     print "p0", p0 

    #cv2.rectangle(frame,(face[0], face[1]), (face[0] + face[2], face[1] + face[3]),(155, 255, 25),2) 
    #Draw circle at initial point 
    cv2.circle(frame,((face[0] + (face[2]/2)),(face[1] + (face[3]/3))),5,(155, 255, 25)) 

    # calculate optical flow 
    p1, st, err = cv2.calcOpticalFlowPyrLK(old_gray, frame_gray, p0, None, **lk_params) 

    # Select good points 
    if st==1: 
     good_new = p1[st==1] 
     good_old = p0[st==1] 

     # draw the tracks 
     for i,(new,old) in enumerate(zip(good_new,good_old)): 
      a,b = new.ravel() 
      c,d = old.ravel() 
      mask = cv2.line(mask, (a,b),(c,d), color[i].tolist(), 2) 
      cv2.circle(frame,(a,b),5,color[i].tolist(),-1) 

    cv2.imshow('frame',frame) 
    k = cv2.waitKey(30) & 0xff 
    if k == 27: 
     break 

    # Now update the previous frame and previous points 
    old_gray = frame_gray.copy() 
    if st==1: 
     p0 = good_new.reshape(-1,1,2) 

cv2.destroyAllWindows() 
cap.release()

來源

2013-12-16 user3105623

我不知道這會有所幫助，但看它是否可能只是面具是無當你畫的軌道：

mask = cv2.line(mask, (a,b),(c,d), color[i].tolist(), 2) 
cv2.circle(frame,(a,b),5,color[i].tolist(),-1)

的cv2.line （）和cv2.circle（）返回Null，正如你在這兩個中的第二個上修復的一樣。嘗試做到第一個也是，所以它看起來像這樣：

cv2.line(mask, (a,b),(c,d), color[i].tolist(), 2) 
cv2.circle(frame,(a,b),5,color[i].tolist(),-1)

我希望工作更好，祝你好運！

來源

2014-02-16 00:11:08

calcOpticalFlowPyrLK丟失單個跟蹤點

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