[英]OpenCV Mat to JavaCV Mat conversion
I am in the process of writing an Android application that uses JavaCV for some facial recognition.我正在编写一个使用 JavaCV 进行面部识别的 Android 应用程序。 I have come across a slight problem where I need to convert from an org.opencv.core.Mat
that the onCameraFrame(CvCameraViewFrame inputFrame)
function returns to a org.bytedeco.javacpp.opencv_core.Mat
that the org.bytedeco.javacpp.opencv_contrib.FaceRecognizer
requires.我遇到了一个小问题,我需要从onCameraFrame(CvCameraViewFrame inputFrame)
函数返回到org.bytedeco.javacpp.opencv_core.Mat
的org.opencv.core.Mat
转换为org.bytedeco.javacpp.opencv_contrib.FaceRecognizer
需要。
I have found similar questions here and here but neither got a working solution.我在这里和这里发现了类似的问题,但都没有找到可行的解决方案。
There's an easier, more efficient way documented at https://github.com/bytedeco/javacpp/issues/38#issuecomment-140728812 , in short:在https://github.com/bytedeco/javacpp/issues/38#issuecomment-140728812中记录了一种更简单、更有效的方法,简而言之:
To JavaCPP/JavaCV:到 JavaCPP/JavaCV:
Mat mat2 = new Mat((Pointer)null) { { address = mat.getNativeObjAddr(); } };
To official Java API of OpenCV: OpenCV的官方Java API:
Mat mat = new Mat(mat2.address());
EDIT : OpenCVFrameConverter now provides an easier and safer way to do this, for example:编辑: OpenCVFrameConverter现在提供了一种更简单、更安全的方法来执行此操作,例如:
OpenCVFrameConverter.ToMat converter1 = new OpenCVFrameConverter.ToMat();
OpenCVFrameConverter.ToOrgOpenCvCoreMat converter2 = new OpenCVFrameConverter.ToOrgOpenCvCoreMat();
Mat mat = ...;
org.opencv.core.Mat cvmat = converter2.convert(converter1.convert(mat));
Mat mat2 = converter2.convert(converter1.convert(cvmat));
You can use java.awt.image.BufferedImage as interface.您可以使用 java.awt.image.BufferedImage 作为接口。
Just convert your org.opencv.core.Mat object to java.awt.image.BufferedImage and then take the result object to convert it to org.bytedeco.javacpp.opencv_core.Mat .只需将您的org.opencv.core.Mat对象转换为java.awt.image.BufferedImage ,然后将结果对象转换为org.bytedeco.javacpp.opencv_core.Mat 。
Now, these are the functions that you will need:现在,这些是您需要的功能:
1) Convert org.opencv.core.Mat to java.awt.image.BufferedImage: 1) 将 org.opencv.core.Mat 转换为 java.awt.image.BufferedImage:
public BufferedImage matToBufferedImage(Mat frame) {
int type = 0;
if (frame.channels() == 1) {
type = BufferedImage.TYPE_BYTE_GRAY;
} else if (frame.channels() == 3) {
type = BufferedImage.TYPE_3BYTE_BGR;
}
BufferedImage image = new BufferedImage(frame.width() ,frame.height(), type);
WritableRaster raster = image.getRaster();
DataBufferByte dataBuffer = (DataBufferByte) raster.getDataBuffer();
byte[] data = dataBuffer.getData();
frame.get(0, 0, data);
return image;
}
2) Convert java.awt.image.BufferedImage to org.bytedeco.javacpp.opencv_core.Mat: 2) 将 java.awt.image.BufferedImage 转换为 org.bytedeco.javacpp.opencv_core.Mat:
public Mat bufferedImageToMat(BufferedImage bi) {
OpenCVFrameConverter.ToMat cv = new OpenCVFrameConverter.ToMat();
return cv.convertToMat(new Java2DFrameConverter().convert(bi));
}
Make sure to have all the necessary jars and imports.确保拥有所有必要的罐子和进口。
You could go deeper into JNI stuff, but for test use cases, this should be enough.您可以更深入地研究 JNI 的内容,但对于测试用例,这应该足够了。
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