带有picamera的python人脸检测树莓派

Question

我是 python 和 opencv 的新手，我正在尝试使用 raspberry pi 构建人脸检测项目。我收到这个错误，这是我的代码

追溯(最近的调用最后):

 File "/home/pi/Desktop/picamera-code/FaceDetection1.0", line 19, in <module>
for frame in 
    camera.capture_continuous(rawCapture, format="bgr", use_video_port=True):

代码:

import numpy as np
import cv2
from picamera.array import PiRGBArray
from picamera import PiCamera
import time


camera = PiCamera()
camera.resolution = (640, 480)
camera.framerate = 32
rawCapture = PiRGBArray(camera, size=(640, 480))

time.sleep(0.1)



face_cascade =  cv2.CascadeClassifier('/home/pi/Downloads/haarcascade_frontalface_default.xml')

for frame in camera.capture_continuous(rawCapture, format="bgr",  use_video_port=True):

    img=np.asarray(frame.array)
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

    faces = face_cascade.detectMultiScale(gray, 1.3, 5)
    for (x,y,w,h) in faces:
        img = cv2.Rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)
        roi_gray = gray[y:y+h, x:x+w]
        roi_color = img[y:y+h, x:x+w]


cv2.imshow('img',img)
cv2.waitKey(0)
cv2.destroyAllWindows()

Answer 1

问题出在您的 camera.capture_continuos 中。第一个值，输出，不能只是一个数组，因为它像文档所说的那样用无限迭代记录。而不是这个你应该放一个输出文件。如果您想要一个流来捕获它，您也可以使用 io.Bytes。

在此link它向您解释了有关如何使用框架以及应将输出重定向到何处的示例。

您可以按照 API 文档中的建议进行操作。获取流并截断它以获取您当前获取的图像:

import io
import time
import picamera
with picamera.PiCamera() as camera:
    stream = io.BytesIO()
    for foo in camera.capture_continuous(stream, format='jpeg'):
    # YOURS:  for frame in camera.capture_continuous(stream, format="bgr",  use_video_port=True):
        # Truncate the stream to the current position (in case
        # prior iterations output a longer image)
        stream.truncate()
        stream.seek(0)
        if process(stream):
            break