KNN火車（）在cv2與opencv 3.0

Question

我想運行使用cv2（python 2.7）和opencv 3.0 k最近鄰居。我複製使用代碼相同的錯誤消息等http://docs.opencv.org/3.0-beta/doc/py_tutorials/py_ml/py_knn/py_knn_understanding/py_knn_understanding.html：

import cv2 
import numpy as np 
import matplotlib.pyplot as plt 
# Feature set containing (x,y) values of 25 known/training data 
trainData = np.random.randint(0,100,(25,2)).astype(np.float32) 
# Labels each one either Red or Blue with numbers 0 and 1 
responses = np.random.randint(0,2,(25,1)).astype(np.float32) 
# Take Red families and plot them 
red = trainData[responses.ravel()==0] 
plt.scatter(red[:,0],red[:,1],80,'r','^') 
# Take Blue families and plot them 
blue = trainData[responses.ravel()==1] 
plt.scatter(blue[:,0],blue[:,1],80,'b','s') 
plt.show() 
newcomer = np.random.randint(0,100,(1,2)).astype(np.float32) 
plt.scatter(newcomer[:,0],newcomer[:,1],80,'g','o') 

#The following line is modified for OpenCV 3.0 
knn = cv2.ml.KNearest_create() 
knn.train(trainData,responses) 
ret, results, neighbours ,dist = knn.find_nearest(newcomer, 3) 

print "result: ", results,"\n" 
print "neighbours: ", neighbours,"\n" 
print "distance: ", dist 

plt.show() 

我修改線KNN = cv2.ml.KNearest_create（）爲OpenCV的3，但是隨後的線路產生一個錯誤「類型錯誤：只長度爲1的數組可以轉換爲Python標量「，我無法弄清楚我應該爲列車功能使用什麼。

Answer 1

你正在通過錯誤的數組長度的KNN算法....掠過你的代碼，我發現你已經錯過了knn.train函數中的cv2.ml.ROW_SAMPLE參數，通過這個參數考慮數組長度作爲整行的1。因此，你的更正後的代碼將是如下：

import cv2 
import numpy as np 
import matplotlib.pyplot as plt 

trainData = np.random.randint(0,100,(51,2)).astype(np.float32) 
responses = np.random.randint(0,2,(51,1)).astype(np.float32) 

red = trainData[responses.ravel()==0] 
plt.scatter(red[:,0],red[:,1],80,'r','^') 
blue = trainData[responses.ravel()==1] 
plt.scatter(blue[:,0],blue[:,1],80,'b','s') 


newcomer = np.random.randint(0,100,(5,2)).astype(np.float32) 
plt.scatter(newcomer[:,0],newcomer[:,1],80,'g','o') 

knn = cv2.ml.KNearest_create() 
knn.train(trainData,cv2.ml.ROW_SAMPLE,responses) 
ret, results, neighbours, dist = knn.findNearest(newcomer, 3) 

print ("results: ", results,"\n") 
print ("neighbours: ", neighbours,"\n") 
print ("distances: ", dist) 

plt.show() 

這裏是我從中得到的結果....