在javacv中将IplImage转换为Mat

Question

我需要帮助将我的IplImage转换为Mat。 我想对图像进行HOGDescriptor计算，然后用SVM对其进行分类，但“compute”需要Mat类型。

你能给出Java中将IplImage转换为Mat的示例吗？

- user2389417

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将IplImage转换为BufferedImage，然后我认为API将允许您从Mat中创建图像。 - anshulkatta

Answer 1

将IplImage转换为Mat很简单。

IplImage iplImage= cvLoadImage("image.png");

Mat matImage = new Mat(iplImage);

反之亦然

- Aqeel Haider

Answer 2

不要混淆官方OpenCV Java绑定（文档请参见这里）与没有文档的JavaCV项目。

如果您使用的是JavaCV，则无需转换IplImage即可使用HOGDescriptor，如JavaCV源代码中所示，HOGDescriptor对象包装器操作CvArr对象：

// javacv/cpp/opencv_objdetect.java:527
public static class HOGDescriptor extends Pointer {
    public HOGDescriptor();
    ...
    public native void setSVMDetector(CvArr _svmdetector);
    ...
    public native void compute(CvArr img, FloatPointer descriptors, CvSize winStride, CvSize padding, CvPoint locations);
    public native void detect(CvArr img, CvPoint foundLocations, DoublePointer weights, double hitThreshold, CvSize winStride, CvSize padding, CvPoint searchLocations);
    public native void detect(CvArr img, CvPoint foundLocations, double hitThreshold, CvSize winStride, CvSize padding, CvPoint searchLocations);
    public native void detectMultiScale(CvArr img, CvRect foundLocations, double hitThreshold, CvSize winStride, CvSize padding, double scale, int groupThreshold);
    public native void detectMultiScale(CvArr img, CvRect foundLocations, DoublePointer foundWeights, double hitThreshold, CvSize winStride, CvSize padding, double scale, double finalThreshold, boolean useMeanshiftGrouping);
    public native void detectMultiScale(CvArr img, CvRect foundLocations, double hitThreshold, CvSize winStride, CvSize padding, double scale, double finalThreshold, boolean useMeanshiftGrouping);
    ...
};

现在，正如您可以在 opencv_core.java 中看到的那样，IplImage包装对象扩展了CvArr：

// javacv/cpp/opencv_core.java:410
public static class IplImage extends CvArr {
    ...
};

所以你不需要进行任何转换。

以下是使用HOGDescriptor.detectMultiScale的示例：

IplImage img = cvLoadImage("image.jpg");
CvRect foundRects = new CvRect(null);
HOGDescriptor hog = new HOGDescriptor(); 
FloatPointer svm = HOGDescriptor.getDefaultPeopleDetector();
hog.setSVMDetector(svm);
hog.detectMultiScale(img, foundRects, 0, cvSize(8,8), cvSize(32,32), 1.05, 2);

- zakinster

Answer 3

这个有一个方法：

opencv_core.cvarrToMat(iplImage);

- vitaliy.gerasymchuk