在之前的例子里遇到了個讓我頭疼的小問題，豎屏時Camera的預覽圖像總是會左旋90度并且不能全屏。
總之很丑很丑顶霞。趾盐。甥啄。
方法一
經過我的研究，網上有很多解決的方法，主要都是通過修改CameraBridgeViewBase.java這個庫文件實現的，該庫文件在你的工程\openCVLibrary340\java\org.openv\android文件夾下添履，如圖
我嘗試了其中的一種方法，在CameraBridgeViewBase.java中找到protected void deliverAndDrawFrame(CvCameraViewFrame frame) 這個方法
將其中的代碼修改如下：
protected void deliverAndDrawFrame(CvCameraViewFrame frame) {
Mat modified;
if (mListener != null) {
modified = mListener.onCameraFrame(frame);
} else {
modified = frame.rgba();
}
boolean bmpValid = true;
if (modified != null) {
try {
Utils.matToBitmap(modified, mCacheBitmap);
} catch(Exception e) {
Log.e(TAG, "Mat type: " + modified);
Log.e(TAG, "Bitmap type: " + mCacheBitmap.getWidth() + "*" + mCacheBitmap.getHeight());
Log.e(TAG, "Utils.matToBitmap() throws an exception: " + e.getMessage());
bmpValid = false;
}
}
if (bmpValid && mCacheBitmap != null) {
Canvas canvas = getHolder().lockCanvas();
if (canvas != null) {
canvas.drawColor(0, android.graphics.PorterDuff.Mode.CLEAR);
/*
//原來的方法
if (BuildConfig.DEBUG)
Log.d(TAG, "mStretch value: " + mScale);
if (mScale != 0) {
canvas.drawBitmap(mCacheBitmap, new Rect(0,0,mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
new Rect((int)((canvas.getWidth() - mScale*mCacheBitmap.getWidth()) / 2),
(int)((canvas.getHeight() - mScale*mCacheBitmap.getHeight()) / 2),
(int)((canvas.getWidth() - mScale*mCacheBitmap.getWidth()) / 2 + mScale*mCacheBitmap.getWidth()),
(int)((canvas.getHeight() - mScale*mCacheBitmap.getHeight()) / 2 + mScale*mCacheBitmap.getHeight())), null);
} else {
canvas.drawBitmap(mCacheBitmap, new Rect(0,0,mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
new Rect((canvas.getWidth() - mCacheBitmap.getWidth()) / 2,
(canvas.getHeight() - mCacheBitmap.getHeight()) / 2,
(canvas.getWidth() - mCacheBitmap.getWidth()) / 2 + mCacheBitmap.getWidth(),
(canvas.getHeight() - mCacheBitmap.getHeight()) / 2 + mCacheBitmap.getHeight()), null);
}
*/
//修改預覽旋轉90度問題
canvas.rotate(90, 0, 0);
float scalew = canvas.getWidth() / (float)mCacheBitmap.getHeight();
float scaleh = canvas.getHeight() / (float)mCacheBitmap.getHeight();
if (scaleh > scalew) {
scalew = scaleh;
}
if (scalew !=0 ) {
canvas.scale(scalew, scalew, 0, 0);
}
canvas.drawBitmap(mCacheBitmap, 0, -mCacheBitmap.getHeight(), null);
//修改預覽旋轉90度問題end
if (mFpsMeter != null) {
mFpsMeter.measure();
mFpsMeter.draw(canvas, 20, 30);
}
getHolder().unlockCanvasAndPost(canvas);
}
}
}
該方法是能解決此問題脑又，但是圖像被放的很大暮胧，分辨率很低，豎屏時也仍然檢測不到人臉问麸。
方法二
直接調用opencv的庫函數方法叔壤，先定義三個全局變量，并且修改onCameraViewStarted（）函數和onCameraFrame（）函數
Mat mRgba;
Mat mRgbaF;
Mat mRgbaT;
public void onCameraViewStarted(int width, int height) {
mRgba = new Mat(height, width, CvType.CV_8UC4);
mRgbaF = new Mat(height, width, CvType.CV_8UC4);
mRgbaT = new Mat(width, width, CvType.CV_8UC4);
}
@Override
public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {
/**
* // TODO Auto-generated method stub
mRgba = inputFrame.rgba();
// Rotate mRgba 90 degrees
Core.transpose(mRgba, mRgbaT);
Imgproc.resize(mRgbaT, mRgbaF, mRgbaF.size(), 0, 0, 0);
Core.flip(mRgbaF, mRgba, 1);
*/
mRgba = inputFrame.rgba();
switch (mOpenCvCameraView.getDisplay().getRotation()) {
case Surface.ROTATION_0: // Vertical portrait
Core.transpose(mRgba, mRgbaT);
Imgproc.resize(mRgbaT, mRgbaF, mRgbaF.size(), 0,0, 0);
Core.flip(mRgbaF, mRgba, 1);
break;
case Surface.ROTATION_90: // 90° anti-clockwise
break;
case Surface.ROTATION_180: // Vertical anti-portrait
Core.transpose(mRgba, mRgbaT);
Imgproc.resize(mRgbaT, mRgbaF, mRgbaF.size(), 0,0, 0);
Core.flip(mRgbaF, mRgba, 0);
break;
case Surface.ROTATION_270: // 90° clockwise
Imgproc.resize(mRgba, mRgbaF, mRgbaF.size(), 0,0, 0);
Core.flip(mRgbaF, mRgba, -1);
break;
default:
}
return mRgba;
}
這樣就能實現豎屏顯示了口叙，并且橫豎屏能隨意切換，但是在我的測試里豎屏時存在圖像被壓縮不能全屏的問題嗅战，比例為橫屏的比例妄田，理論上如果在 case Surface.ROTATION_0: // Vertical portrait下做替換如下：
Imgproc.resize(mRgbaT, mRgbaF, mRgbaF.size(), 0,0, 0);
Imgproc.resize(mRgbaT, mRgbaF, mRgbaT.size(), 0,0, 0);
Imgproc.resize(mRgba, mRgba, mRgbaT.size(),0,0,0);
Core.flip(mRgbaF, mRgba, 1);
應該能解決圖像比例不對的問題，但是測試發(fā)現驮捍，一直是黑屏并沒有顯示23333具體原因不明疟呐。。东且。
所以這個方法的達不到我想要的效果启具，不知道有沒有同志能有更好的改法，能不改opencv庫文件珊泳，來解決這個比例的問題鲁冯。
方法三
我通過查閱opencv android sdk 給出的sample 發(fā)現了一個解決這個問題的新思路。核心思想就是鎖定app的方向旋轉色查，將其固定為Landscape薯演，即水平模式
通過修改AndroidMainifest.xml來實現，無需修改CameraBridgeViewBase.java這個庫文件
重點
給AndroidMainifest.xml里的<application標簽添加如下代碼android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
給<activity標簽添加android:screenOrientation="landscape"
即把AndroidMainifest.xml修改為
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.aaa.facedetection1_0">
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" android:required="false" />
<uses-feature android:name="android.hardware.camera.autofocus" android:required="false" />
<uses-feature android:name="android.hardware.camera.front" android:required="false" />
<uses-feature android:name="android.hardware.camera.front.autofocus" android:required="false" />
<application
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:theme="@android:style/Theme.NoTitleBar.Fullscreen">
<activity android:name=".MainActivity"
android:screenOrientation="landscape">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
這樣就能鎖定橫屏并且全屏顯示了
另外附上MainActivity.java代碼和activity_main.xml
activity_main.xml為
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/relative"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.aaa.facedetection1_0.MainActivity">
<org.opencv.android.JavaCameraView
android:id="@+id/openCvCameraView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:visibility="gone"
app:camera_id="any"
app:show_fps="true"
/>
</RelativeLayout>
MainActivity.java
package com.example.aaa.facedetection1_0;
import android.app.Activity;
import android.content.Context;
import android.content.res.Configuration;
import android.graphics.Camera;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.TextView;
import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.CameraBridgeViewBase;
import org.opencv.android.JavaCameraView;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.android.OpenCVLoader;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.MatOfRect;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.core.Size;
import org.opencv.imgproc.Imgproc;
import org.opencv.objdetect.CascadeClassifier;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import static com.example.aaa.facedetection1_0.R.id.openCvCameraView;
public class MainActivity extends Activity implements CameraBridgeViewBase.CvCameraViewListener{
private CameraBridgeViewBase openCvCameraView;
private CascadeClassifier cascadeClassifier;
private Mat grayscaleImage;
private int absoluteFaceSize;
public static int CAMERA_FRONT = 0;
public static int CAMERA_BACK = 1;
private int camera_scene = CAMERA_BACK;
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
@Override
public void onManagerConnected(int status){
switch (status){
case LoaderCallbackInterface.SUCCESS:
initializeOpenCVDependencies();
break;
default:
super.onManagerConnected(status);
break;
}
}
};
private void initializeOpenCVDependencies(){
try{
InputStream is = getResources().openRawResource(R.raw.lbpcascade_frontalface);
File casadeDir = getDir("cascade", Context.MODE_PRIVATE);
File mCascadeFile = new File(casadeDir,"lbpcascade_frontalface.xml");
FileOutputStream os = new FileOutputStream(mCascadeFile);
byte[] buffer = new byte[4096];
int bytesRead;
while ((bytesRead = is.read(buffer)) != -1){
os.write(buffer, 0, bytesRead);
}
is.close();
os.close();
cascadeClassifier = new CascadeClassifier(mCascadeFile.getAbsolutePath());
} catch (Exception e) {
Log.e("OpenCVActivity","Error Loading casade",e);
}
openCvCameraView.enableView();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
setContentView(R.layout.activity_main);
final RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.id.relative);
openCvCameraView = new JavaCameraView(this, CameraBridgeViewBase.CAMERA_ID_BACK)
openCvCameraView.setCvCameraViewListener(this);
final Button button = new Button(MainActivity.this);
button.setText("切換攝像頭");
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v){
if (camera_scene == CAMERA_FRONT) {
relativeLayout.removeAllViews();
openCvCameraView.disableView();
openCvCameraView = null;
cascadeClassifier = null;
openCvCameraView = new JavaCameraView(MainActivity.this, CameraBridgeViewBase.CAMERA_ID_BACK);
openCvCameraView.setCvCameraViewListener(MainActivity.this);
openCvCameraView.setCameraIndex(CameraBridgeViewBase.CAMERA_ID_BACK);
camera_scene = CAMERA_BACK;
relativeLayout.addView(openCvCameraView);
relativeLayout.addView(button);
initializeOpenCVDependencies();
} else {
relativeLayout.removeAllViews();
openCvCameraView.disableView();
openCvCameraView = null;
cascadeClassifier = null;
openCvCameraView = new JavaCameraView(MainActivity.this, CameraBridgeViewBase.CAMERA_ID_FRONT);
openCvCameraView.setCvCameraViewListener(MainActivity.this);
openCvCameraView.setCameraIndex(CameraBridgeViewBase.CAMERA_ID_FRONT);
camera_scene = CAMERA_FRONT;
relativeLayout.addView(openCvCameraView);
relativeLayout.addView(button);
initializeOpenCVDependencies();
}
}
});
relativeLayout.addView(openCvCameraView);
relativeLayout.addView(button);
if (camera_scene == CAMERA_FRONT) {
openCvCameraView.setCameraIndex(CameraBridgeViewBase.CAMERA_ID_FRONT);
} else if (camera_scene == CAMERA_BACK) {
openCvCameraView.setCameraIndex(CameraBridgeViewBase.CAMERA_ID_BACK);
}
}
@Override
public void onCameraViewStarted(int width, int height){
grayscaleImage = new Mat(height, width, CvType.CV_8UC4);
absoluteFaceSize = (int)(height * 0.2);
}
@Override
public void onCameraViewStopped(){
}
@Override
public Mat onCameraFrame(Mat aInputFrame){
Imgproc.cvtColor(aInputFrame, grayscaleImage, Imgproc.COLOR_RGBA2RGB);
//使前置的圖像也是正的
if (camera_scene == CAMERA_FRONT) {
Core.flip(aInputFrame, aInputFrame, 1);
Core.flip(grayscaleImage, grayscaleImage, 1);
}
MatOfRect faces = new MatOfRect();
if (cascadeClassifier != null){
cascadeClassifier.detectMultiScale(grayscaleImage,faces,1.1,2,2,new Size(absoluteFaceSize,absoluteFaceSize),new Size());
}
Rect[] faceArray = faces.toArray();
for (int i = 0; i < faceArray.length; i++)
Imgproc.rectangle(aInputFrame, faceArray[i].tl(), faceArray[i].br(), new Scalar(0, 255, 0, 255), 1);
return aInputFrame;
}
@Override
public void onResume(){
super.onResume();
if (!OpenCVLoader.initDebug()){
OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_4_0, this, mLoaderCallback);
} else {
mLoaderCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);
}
}
}
添加了切換前后置攝像頭的功能
注意秧了，因為在要AndroidMainifest.xml里要使用android:theme="@android:style/Theme.NoTitleBar.Fullscreen"這個主題跨扮，需要我們繼承Activity這個類而不是之前一直默認使用的AppCompatActivity，即.java文件開始應該為
public class MainActivity extends Activity implements CameraBridgeViewBase.CvCameraViewListener{
否則程序無法運行，一打開就閃退
后置豎屏
后置橫屏
前置橫屏
可以發(fā)現這個方法還是有問題的衡创，因為是直接鎖定橫屏的帝嗡，豎屏時狀態(tài)欄和按鈕不會旋轉至豎屏，并且仍然是只有在橫屏下人臉識別才能正常運行璃氢，這個可能是因為opencv這個sdk寫的時候時是默認橫屏圖像才是正的吧
附上一個類似問題解決答案的來源
https://stackoverflow.com/questions/14816166/rotate-camera-preview-to-portrait-android-opencv-camera
看來還得好好的啃android開發(fā)和opencv的知識去哟玷，畢竟也是半路上的車，遭不住鞍卫场Ｍ虢怠！塘秦！要學習的東西好多讼渊。。尊剔。
總不能一直做調參俠吧23333
