使用OpenCV检测简单的几何形状[Java] [英] Detecting simple geometric shapes using OpenCV [Java]
问题描述
我正在编写一个检测简单几何形状的Java应用程序.
I'm programming a Java application that detects simple geometric shapes.
以下Python代码用作参考:如何使用OpenCV检测简单的几何形状
The following Python code is used as a reference: How to detect simple geometric shapes using OpenCV
这是[Python]的一些代码:
This is some of the code [Python]:
contours,h = cv2.findContours(thresholdedImage,1,2)
for cnt in contours:
approx = cv2.approxPolyDP(cnt,0.01*cv2.arcLength(cnt,True),True)
print len(approx)
if len(approx)==5:
print "pentagon"
cv2.drawContours(img,[cnt],0,255,-1)
elif len(approx)==3:
print "triangle"
cv2.drawContours(img,[cnt],0,(0,255,0),-1)
elif len(approx)==4:
print "square"
cv2.drawContours(img,[cnt],0,(0,0,255),-1)
elif len(approx) == 9:
print "half-circle"
cv2.drawContours(img,[cnt],0,(255,255,0),-1)
elif len(approx) > 15:
print "circle"
cv2.drawContours(img,[cnt],0,(0,255,255),-1)
使用Java的OpenCV方法,我无法提取近似轮廓的"len"(长度)属性(以便确定已检测到的形状).
Using Java's OpenCV methods, I'm unable to extract the "len" (length) property (in order to determine what shape has been detected) of an approximated contour.
打印出两个轮廓会产生[Java]:
Printing out a couple of contours produces [Java]:
[ 4*1*CV_32SC2, isCont=true, isSubmat=false, nativeObj=0x23ac75f0, dataAddr=0x1c7c66c0 ]
[ 5*1*CV_32SC2, isCont=true, isSubmat=false, nativeObj=0x23ac7200, dataAddr=0x1c0e5fc0 ]
etc.
我想从上面的代码中获取特定轮廓对象的点数-4
和5
.
I'd like to get the number of points of a specific contour object -- the 4
and 5
from the code above.
我知道我可以将其转换为字符串,然后提取数字,但是必须有更好的方法,对吧?
I know I could convert it to a String and then extract the numbers, but there must be a better way, right?
感谢您的答复.
推荐答案
这应该可以解决问题. (假设您已经将yourImage
存储在MatOfPoint2f
对象中).
This should do the trick. (Assuming you already have yourImage
stored in a MatOfPoint2f
object).
MatOfPoint2f approx = new MatOfPoint2f();
Imgproc.approxPolyDP(yourImage, approx, Imgproc.arcLength(yourImage, true) * 0.02, true);
long count = approx.total();
if (count == 5) {
// this is a pentagon
}
检查此查看total()
与Python或C ++等其他语言相比,Java上的OpenCV变得有些棘手.
OpenCV on Java becomes a bit tricky compared with other languages like Python or C++.
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