我遇到了形态学面具的错误

Question

我写了一个找到2个ROI的程序，在2个独立的帧中选择它们，然后计算每个帧的绿色像素数。它工作正常，但当我为相机应用形态学面具时，它给了我错误：/home/pi/opencv/opencv-3.4.0/modules/core/src/arithm.cpp:1769：错误：（ - 209）较低boundary既不是与src相同大小和相同类型的数组，也不是函数inRange中的标量我该如何解决这个问题？

这里出现问题

maskClose=cv2.morphologyEx(maskOpen,cv2.MORPH_CLOSE,kernelClose) 
 maskFinal=maskClose ... for i in range(len(conts)): 
 x,y,w,h=cv2.boundingRect(conts[i]) area=maskFinal[y:y+h, x:x+w] pixcount = 
 cv2.inRange(area,lowerBound,upperBound ) pixNum = cv2.countNonZero(pixcount)

完整代码

import cv2
import numpy as np
from picamera.array import PiRGBArray
from picamera import PiCamera
import time
import sys
prevNrOfContours = 0
lowerBound=np.array([43,53,30])
upperBound=np.array([132,255,255])


camera = PiCamera()
camera.rotation = 180
camera.resolution = (640, 480)
camera.framerate = 30
font=cv2.FONT_HERSHEY_SIMPLEX

rawCapture = PiRGBArray(camera, size=(640, 480))
GREEN_MIN = np.array([0, 0, 0])
GREEN_MAX = np.array([0, 0, 0])



# allow the camera to warmup
time.sleep(0.1)
kernelOpen=np.ones((5,5))
kernelClose=np.ones((20,20))
# capture frames from the camera
for frame in camera.capture_continuous(rawCapture, format="bgr", use_video_port=True):
        img = frame.array
        imgHSV= cv2.cvtColor(img,cv2.COLOR_BGR2HSV)
        mask=cv2.inRange(imgHSV,lowerBound,upperBound)
#morphology
        maskOpen=cv2.morphologyEx(mask,cv2.MORPH_OPEN,kernelOpen)
        maskClose=cv2.morphologyEx(maskOpen,cv2.MORPH_CLOSE,kernelClose)
        maskFinal=maskClose
        _, conts, _=cv2.findContours(maskFinal.copy(),cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_NONE)
        nrOfContours = len(conts)
        for i in range(len(conts)):
            x,y,w,h=cv2.boundingRect(conts[i])
            area=maskFinal[y:y+h, x:x+w] ######## problem is here
            pixcount = cv2.inRange(area,lowerBound,upperBound )
            pixNum = cv2.countNonZero(pixcount)
            print("Area No."+str(i), "Green pixels = " + str(no_black))
            cv2.rectangle(img,(x,y),(x+w,y+h),(0,0,255), 2)
            cv2.imshow("area" + str(i), area)
        # close unnecessary windows
        if prevNrOfContours > nrOfContours:
          for i in range(nrOfContours, prevNrOfContours):
            cv2.destroyWindow("area" + str(i))
        prevNrOfContours = nrOfContours
        cv2.imshow("cam",img)

        # clear the stream in preparation for the next frame
        key = cv2.waitKey(1) & 0xFF
        rawCapture.truncate(0)
        if key == ord("q"):
                break

Answer 1

你正在创建maskFinal的子图像。 maskFinal是二进制图像，与3通道lowerBound不兼容。

要解决这个问题，你实际上可以放弃行pixcount = cv2.inRange(area,lowerBound,upperBound )。绿色区域的蒙面图像为白色，因此计算非零值就足够了。

注意：当前子图像包括形态变换。如果你不想计算由那些引起的像素，你将不得不创建一个mask的子图像