OpenCV報錯

OpenCV官方栗子執行報錯：

Running DetectFaceDemo
Detected 0 faces Writing faceDetection.png *libpng warning: Image width is zero in IHDR libpng warning: Image height is zero in IHDR libpng error: Invalid IHDR data*

 原因：路徑問題，java代碼getPath()返回的路徑前面多個/,c++中不識別，解決方法如下。

System.out.println("\nRunning DetectFaceDemo");
// Create a face detector from the cascade file in the resources
// directory.
CascadeClassifier faceDetector = new CascadeClassifier(getClass().getResource("/lbpcascade_frontalface.xml").getPath());
Mat image = Imgcodecs.imread(getClass().getResource("/lena.png").getPath());

 修改為：

final URI xmlUri = getClass().getResource("/lbpcascade_frontalface.xml").toURI();
final CascadeClassifier faceDetector = new CascadeClassifier(new File(xmlUri).getAbsolutePath());
final URI imageUri = getClass().getResource("/4.jpg").toURI();
Mat image = Imgcodecs.imread(new File(imageUri).getAbsolutePath());