Question

我正在尝试通过网络摄像头进行对象检测（检测手机），但是我的代码未执行。以下是我的代码：

import cv2
import numpy as np


def sift_detector(new_image,image_template):
#Function that compares input image to template. 
#it then returns the number of sift matches between them

   image1 = cv2.cvtColor(new_image,cv2.COLOR_BGR2GRAY)
   image2 = image_template

# create a sift dectector object
#sift = cv2.sift()
   sift = cv2.xfeatures2d.SIFT_create()

#obtain the keypoints and descriptors usng SIFT
   keypoints_1,descriptors_1 = sift.detectAndCompute(image1 , None)
   keypoints_2,descriptors_2 = sift.detectAndCompute(image2 , None)

#define parameters for our flann matcher
   FLANN_INDEX_KDTREE = 0
   index_params = dict(algorithm = FLANN_INDEX_KDTREE,tress = 3)
   search_params = dict(checks = 100)

#create the flann matcher object
   flann = cv2.FlannBasedMatcher(index_params,search_params)

# obtain matches using knn method
# the result 'matchs' is the number of similar matches found in both images
   matches = flann.knnMatch(descriptors_1,descriptors_2,k = 2)

# Store good matches using lowe's ratio test
   good_matches=[]
   for m,n in matches:
       if m.distance < 0.7 *n.distance:
           good_matches.append(m)
   return len(good_matches)

这是我用来检测物体的SIFT检测器功能下面是VideoCapture代码：

cap = cv2.VideoCapture(0)

# laod image template, this is our reference image
image_template = cv2.imread('images/iphone.jpg',0)

while True:
#get webcam images
   ret,frame = cap.read()

#get height and width of webcam frame
   height,width = 480,640 

#Define ROI BOX Dimensions
   top_left_x = int (width / 3)
   top_left_y = int((height / 2) + (height / 4))
   bottom_right_x = int((width / 3) * 2 )
   bottom_right_y = int( (height / 2) - (height / 4) )

# Draw rectangular window of our region of interest
   cv2.rectangle(frame,(top_left_x,top_left_y), 
   (bottom_right_x,bottom_right_y),255 , 3)

# crop window of observation we define above
   cropped = frame[bottom_right_y:top_left_y,top_left_x :bottom_right_x]

# flip frame orientation horizontally
   frame = cv2.flip(frame,1)

# get number of sift matches
   matches = sift_detector(cropped,image_template)

#display status string showing the current no of matches
   cv2.putText(frame,str(matches),(450,450),cv2.FONT_HERSHEY_COMPLEX,2, 
   (0,0,255),1)


#our threshold to indicate object detection
# we use 10 since the sift detector returns little false positives
   threshold = 10

# if matches exceed our threshold then object has been detected
   if matches > threshold :
       cv2.rectangle(frame,(top_left_x,top_left_y), 
       (bottom_right_x,bottom_right_y),(0,0,255),3)
       cv2.putText(frame,'object found',(50,50),cv2.FONT_HERSHEY_COMPLEX,2, 
       (0,0,255),2)

   cv2.imshow('object detector using sift',frame)
   if cv2.waitKey(1) == 13: #13 is enter key
       break
cap.release()
cv2.destroyAllWindows()

当我尝试解决一个错误时，会弹出其他错误。我得到的最常见的错误是NoneType错误。我想知道是否还有其他我可以参考的代码。我是该领域的初学者。

Opencv3错误无法执行代码引发多个错误，视频捕获不起作用

0 个答案: