如何在Opencv (Android)中绘制矩形轮廓线？
如何在Opencv (Android)中绘制矩形轮廓线？
提问于 2016-04-27 06:47:01
我想在轮廓线周围画长方形。我在Python中做得很好，但是当我将代码转换为android时，应用程序每次都会崩溃。
ImageView im = (ImageView) findViewById(R.id.sampleImageView);
// Bitmap bitmap = ((BitmapDrawable) im.getDrawable()).getBitmap();
Bitmap bitmap = BitmapFactory.decodeResource(getApplicationContext().getResources(), R.drawable.room);
Mat src = new Mat();
Utils.bitmapToMat(bitmap, src);
Mat gray = new Mat();
Imgproc.cvtColor(src, gray, Imgproc.COLOR_RGBA2GRAY);
Imgproc.Canny(gray, gray, 50, 200);
Imgproc.threshold(gray, gray, 10, 255, Imgproc.THRESH_OTSU);
List<MatOfPoint> contours = new ArrayList<>();
Mat hierarchy = new Mat();
Imgproc.findContours(gray, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE, new Point(0, 0));
Imgproc.drawContours(src, contours, -1, new Scalar(0, 0, 255), -1);
/********************************/
MatOfPoint2f approxCurve = new MatOfPoint2f();
// For each contour found
for (int i = 0; i < contours.size(); i++)
{
//Convert contours(i) from MatOfPoint to MatOfPoint2f
MatOfPoint2f contour2f = new MatOfPoint2f(contours.get(i).toArray());
//Processing on mMOP2f1 which is in type MatOfPoint2f
double approxDistance = Imgproc.arcLength(contour2f, true) * 0.02;
Imgproc.approxPolyDP(contour2f, approxCurve, approxDistance, true);
// Convert back to MatOfPoint
MatOfPoint points = new MatOfPoint(approxCurve.toArray());
// Get bounding rect of contour
Rect rect = Imgproc.boundingRect(points);
// draw enclosing rectangle (all same color, but you could use variable i to make them unique)
Imgproc.rectangle(src, new Point(rect.x,rect.y), new Point(rect.x+rect.width,rect.y+rect.height), new Scalar(255,0,255), 3);
}
/*******************************/
Utils.matToBitmap(src, bitmap);
im.setImageBitmap(bitmap);误差
No implementation found for void org.opencv.imgproc.Imgproc.rectangle_1(long, double, double, double, double, double, double, double, double, int) (tried Java_org_opencv_imgproc_Imgproc_rectangle_11 and Java_org_opencv_imgproc_Imgproc_rectangle_11__JDDDDDDDDI)
04-27 11:38:30.655 12221-12221/com.objectdetection.mrawan.objectdetection D/AndroidRuntime: Shutting down VM
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: FATAL EXCEPTION: main
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: Process: com.objectdetection.mrawan.objectdetection, PID: 12221
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: java.lang.IllegalStateException: Could not execute method of the activity
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: at android.view.View$1.onClick(View.java:4096)
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: at android.view.View.performClick(View.java:4856)
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: at android.view.View$PerformClick.run(View.java:19956)
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: at android.os.Handler.handleCallback(Handler.java:739)
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:95)
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: at android.os.Looper.loop(Looper.java:211)
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5371)
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:372)
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:945)
04-27 11:38:30.665 12221-12221/com.objectdetection.mrawan.objectdetection E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:740)回答 1
Stack Overflow用户
发布于 2016-06-23 11:02:19
@Override
public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {
mRgba = inputFrame.rgba();
contours = new ArrayList<MatOfPoint>();
hierarchy = new Mat();
Imgproc.GaussianBlur(mRgba,mIntermediateMat,new Size(9,9),2,2);
Imgproc.Canny(mRgba, mIntermediateMat, 80, 100);
Imgproc.findContours(mIntermediateMat, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE, new Point(0, 0));
/* Mat drawing = Mat.zeros( mIntermediateMat.size(), CvType.CV_8UC3 );
for( int i = 0; i< contours.size(); i++ )
{
Scalar color =new Scalar(Math.random()*255, Math.random()*255, Math.random()*255);
Imgproc.drawContours( drawing, contours, i, color, 2, 8, hierarchy, 0, new Point() );
}*/
hierarchy.release();
// Imgproc.cvtColor(mIntermediateMat, mRgba, Imgproc.COLOR_GRAY2RGBA, 4)
/* Mat drawing = Mat.zeros( mIntermediateMat.size(), CvType.CV_8UC3 );
for( int i = 0; i< contours.size(); i++ )
{
Scalar color =new Scalar(Math.random()*255, Math.random()*255, Math.random()*255);
Imgproc.drawContours( drawing, contours, i, color, 2, 8, hierarchy, 0, new Point() );
}*/
for ( int contourIdx=0; contourIdx < contours.size(); contourIdx++ )
{
// Minimum size allowed for consideration
MatOfPoint2f approxCurve = new MatOfPoint2f();
MatOfPoint2f contour2f = new MatOfPoint2f( contours.get(contourIdx).toArray() );
//Processing on mMOP2f1 which is in type MatOfPoint2f
double approxDistance = Imgproc.arcLength(contour2f, true)*0.02;
Imgproc.approxPolyDP(contour2f, approxCurve, approxDistance, true);
//Convert back to MatOfPoint
MatOfPoint points = new MatOfPoint( approxCurve.toArray() );
// Get bounding rect of contour
Rect rect = Imgproc.boundingRect(points);
Core.rectangle(mRgba, new Point(rect.x, rect.y), new Point(rect.x + rect.width, rect.y + rect.height), new Scalar(255, 0, 0, 255), 3);
}
return mRgba;
}尝试一下，它对我非常有效(如果有任何错误，根据opencv库版本编写代码)。core.rectangle像这样变成了Imgproc.rectangle
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/36882329
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