error: (-2:Unspecified error) FAILED: fs.is_open(). Can‘t open “res10_300x300_ssd_iter_140000_fp16.“

**

在做opencv dnn 人脸检测的时候一直遇到这个问题，翻遍了谷歌、csdn、Stack Overflow，毛都没有。最后自己摸索出来解决方案如下：

**
1、使用绝对路径
2、使用了绝对路径还不行，试试标注下参数，例如：

readNetFromCaffe(prototxt="D:\github\Opencv-Algorithm-summary\deploy.prototxt"

3、以上方法还是没解决，试试把“\”改为“\\”。
笔者这边正常运行的代码：

#coding=utf-8
import numpy as np
import cv2,os,time

def show_detections(image,detections):
    h,w,c=image.shape
    for i in range(0, detections.shape[2]):
        confidence = detections[0, 0, i, 2]
        if confidence >0.6:
            box = detections[0, 0, i, 3:7] * np.array([w, h, w, h])
            (startX, startY, endX, endY) = box.astype("int")
            text = "{:.2f}%".format(confidence * 100)
            y = startY - 10 if startY - 10 > 10 else startY + 10
            cv2.rectangle(image, (startX, startY), (endX, endY),
                (0, 255,0), 1)
            cv2.putText(image, text, (startX, y),
                cv2.FONT_HERSHEY_SIMPLEX, 0.45, (0, 255, 0), 2)
    return image
 
def detect_img(net,image):
    blob = cv2.dnn.blobFromImage(cv2.resize(image, (300, 300)), 1.0,
	(300, 300), (104.0, 177.0, 123.0))
    net.setInput(blob)
    start=time.time()
    detections = net.forward()
    end=time.time()
    print(end-start)
    return show_detections(image,detections)
 
def test_dir(net,dir="images"):
    files=os.listdir(dir)
    for file in files:
        filepath=dir+"/"+file
        img=cv2.imread(filepath)
        showimg=detect_img(net,img)
        cv2.imshow("img",showimg)
        cv2.waitKey()
 
def test_camera(net):
    cap=cv2.VideoCapture(0)
    while True:
        ret,img=cap.read()
        if not ret:
            break
        showimg=detect_img(net,img)
        cv2.imshow("img",showimg)
        cv2.waitKey(1)      
    
if __name__=="__main__":
    net = cv2.dnn.readNetFromCaffe(prototxt="D:\github\Opencv-Algorithm-summary\deploy.prototxt",caffeModel="D:\\github\\Opencv-Algorithm-summary\\res10_300x300_ssd_iter_140000_fp16.caffemodel")
    #net =cv2.dnn.readNetFromTensorflow(model="D:\opencv\opencv\sources\samples\dnn\face_detector\opencv_face_detector_uint8.pb",config="D:\opencv\opencv\sources\samples\dnn\face_detector\opencv_face_detector.pbtxt")
    #test_dir(net)
    test_camera(net)