OpenCV Hough Circle Transform需要8位图像 [英] OpenCV Hough Circle Transform needs 8-bit image

问题描述

我正在使用RaspberryPi使用Hough Circle Transform，当我进行ROI检查像这样的圆形时:

I am working with Hough Circle Transform with my RaspberryPi and when I take a ROI to check for circle like this:

for (x,y,w,h) in trafficLights:
    cv2.rectangle(image,(x,y),(x+w,y+h),(0,0,255),2)
    roi = image[y:y+h,x:x+w]
    roi = cv2.medianBlur(roi,5)

    circles = cv2.HoughCircles(roi,cv2.HOUGH_GRADIENT,1,20,
                       param1=50,param2=60,minRadius=0,maxRadius=0)
    circles = numpy.uint16(numpy.around(circles))

    for i in circles[0,:]:
        if i[2] < 100:
            cv2.circle(image,(i[0],i[1]),i[2],(0,255,0),2)
            cv2.circle(image,(i[0],i[1]),2,(0,0,255),3)
            if i[1] > 315:
                print "Green Light"
            else:
                print "Red Light"

我收到此错误

The source image must be 8-bit, single-channel in function cvHoughCircles

如何将ROI转换为8位图像，或者该错误表示其他什么意思

How can I transform the ROI to become an 8-bit image or does the error mean something else

先谢谢您！

推荐答案

感谢Miki和bpachev的帮助！

Thank you Miki and bpachev for the help!

第一个错误意味着您需要像这样将其转换为灰度

The first error means that you need to convert it to grayscale like this

gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) 

NoneType错误意味着未找到任何圆圈，为避免错误，您可以添加此if语句

And the NoneType error means that no circles were found so to advoid the error you can add this if statement

if circles is not None:
    circles = numpy.round(circles[0, :]).astype("int")

然后，因为在我知道没有圈的地方发现了任何圈，所以我必须在检测器的设置下玩转.

Then since no circles were found where I knew there were circles I had to play around with the settings of the detector.

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