我正在使用minSdkVersion 21和targetSdkVersion 28在Android Studio上进行一些工作。 该程序执行光电描记术,通过使用 前置摄像头实时检测与面部光吸收成比例的信号,并提取呼吸活动。 我的想法是:将人脸放在黑色矩形内,只研究其中的一部分图像。
rectangle.xml (可绘制图):
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<solid android:color="@android:color/transparent"/>
<corners android:radius="12px"/>
<stroke android:width="2dip" android:color="#000000"/>
</shape>
activity_main.xml :
<?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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="edmt.dev.androidcamera2api.MainActivity">
<TextureView
android:id="@+id/textureView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="@+id/btnCapture"
/>
<Button
android:id="@+id/btnCapture"
android:text="CAPTURE"
android:layout_alignParentBottom="true"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<ImageView
android:id="@+id/rectimage"
android:layout_width="196dp"
android:layout_height="200dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="145dp"
android:src="@drawable/rectangle"></ImageView>
</RelativeLayout>
MainActivity.java :
package edmt.dev.androidcamera2api;
import [...]
public class MainActivity extends AppCompatActivity {
private Button btnCapture;
private TextureView textureView;
//Check state orientation of output image
private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
static{
ORIENTATIONS.append(Surface.ROTATION_0,90);
ORIENTATIONS.append(Surface.ROTATION_90,0);
ORIENTATIONS.append(Surface.ROTATION_180,270);
ORIENTATIONS.append(Surface.ROTATION_270,180);
}
private String cameraId;
private CameraDevice cameraDevice;
private CameraCaptureSession cameraCaptureSessions;
private CaptureRequest.Builder captureRequestBuilder;
private Size imageDimension;
private ImageReader imageReader;
//Save to FILE
private File file;
private static final int REQUEST_CAMERA_PERMISSION = 200;
private boolean mFlashSupported;
private Handler mBackgroundHandler;
private HandlerThread mBackgroundThread;
CameraDevice.StateCallback stateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(@NonNull CameraDevice camera) {
cameraDevice = camera;
createCameraPreview();
}
@Override
public void onDisconnected(@NonNull CameraDevice cameraDevice) {
cameraDevice.close();
}
@Override
public void onError(@NonNull CameraDevice cameraDevice, int i) {
cameraDevice.close();
cameraDevice=null;
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textureView = (TextureView)findViewById(R.id.textureView);
//From Java 1.4 , you can use keyword 'assert' to check expression true or false
assert textureView != null;
textureView.setSurfaceTextureListener(textureListener);
btnCapture = (Button)findViewById(R.id.btnCapture);
btnCapture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
takePicture();
}
});
}
private void takePicture() {
if(cameraDevice == null)
return;
CameraManager manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE);
try{
CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraDevice.getId());
Size[] jpegSizes = null;
if(characteristics != null)
jpegSizes = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP)
.getOutputSizes(ImageFormat.JPEG);
//Capture image with custom size
int width = 640;
int height = 480;
if(jpegSizes != null && jpegSizes.length > 0)
{
width = jpegSizes[0].getWidth();
height = jpegSizes[0].getHeight();
}
final ImageReader reader = ImageReader.newInstance(width,height,ImageFormat.JPEG,1);
List<Surface> outputSurface = new ArrayList<>(2);
outputSurface.add(reader.getSurface());
outputSurface.add(new Surface(textureView.getSurfaceTexture()));
final CaptureRequest.Builder captureBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
captureBuilder.addTarget(reader.getSurface());
captureBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
//Check orientation base on device
int rotation = getWindowManager().getDefaultDisplay().getRotation();
captureBuilder.set(CaptureRequest.JPEG_ORIENTATION,ORIENTATIONS.get(rotation));
file = new File(Environment.getExternalStorageDirectory()+"/"+UUID.randomUUID().toString()+".jpg");
ImageReader.OnImageAvailableListener readerListener = new ImageReader.OnImageAvailableListener() {
@Override
public void onImageAvailable(ImageReader imageReader) {
Image image = null;
try{
image = reader.acquireLatestImage();
ByteBuffer buffer = image.getPlanes()[0].getBuffer();
byte[] bytes = new byte[buffer.capacity()];
buffer.get(bytes);
save(bytes);
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
finally {
{
if(image != null)
image.close();
}
}
}
private void save(byte[] bytes) throws IOException {
OutputStream outputStream = null;
try{
outputStream = new FileOutputStream(file);
outputStream.write(bytes);
}finally {
if(outputStream != null)
outputStream.close();
}
}
};
reader.setOnImageAvailableListener(readerListener,mBackgroundHandler);
final CameraCaptureSession.CaptureCallback captureListener = new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
super.onCaptureCompleted(session, request, result);
Toast.makeText(MainActivity.this, "Saved "+file, Toast.LENGTH_SHORT).show();
createCameraPreview();
}
};
cameraDevice.createCaptureSession(outputSurface, new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
try{
cameraCaptureSession.capture(captureBuilder.build(),captureListener,mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
}
},mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void createCameraPreview() {
try{
SurfaceTexture texture = textureView.getSurfaceTexture();
assert texture != null;
texture.setDefaultBufferSize(imageDimension.getWidth(),imageDimension.getHeight());
Surface surface = new Surface(texture);
captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
captureRequestBuilder.addTarget(surface);
cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
if(cameraDevice == null)
return;
cameraCaptureSessions = cameraCaptureSession;
updatePreview();
}
@Override
public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
Toast.makeText(MainActivity.this, "Changed", Toast.LENGTH_SHORT).show();
}
},null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void updatePreview() {
if(cameraDevice == null)
Toast.makeText(this, "Error", Toast.LENGTH_SHORT).show();
captureRequestBuilder.set(CaptureRequest.CONTROL_MODE,CaptureRequest.CONTROL_MODE_AUTO);
try{
cameraCaptureSessions.setRepeatingRequest(captureRequestBuilder.build(),null,mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void openCamera() {
CameraManager manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE);
try{
cameraId = manager.getCameraIdList()[0];
CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
assert map != null;
imageDimension = map.getOutputSizes(SurfaceTexture.class)[0];
//Check realtime permission if run higher API 23
if(ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)
{
ActivityCompat.requestPermissions(this,new String[]{
Manifest.permission.CAMERA,
Manifest.permission.WRITE_EXTERNAL_STORAGE
},REQUEST_CAMERA_PERMISSION);
return;
}
manager.openCamera(cameraId,stateCallback,null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
TextureView.SurfaceTextureListener textureListener = new TextureView.SurfaceTextureListener() {
@Override
public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int i, int i1) {
openCamera();
}
@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int i, int i1) {
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
return false;
}
@Override
public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {
}
};
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if(requestCode == REQUEST_CAMERA_PERMISSION)
{
if(grantResults[0] != PackageManager.PERMISSION_GRANTED)
{
Toast.makeText(this, "You can't use camera without permission", Toast.LENGTH_SHORT).show();
finish();
}
}
}
@Override
protected void onResume() {
super.onResume();
startBackgroundThread();
if(textureView.isAvailable())
openCamera();
else
textureView.setSurfaceTextureListener(textureListener);
}
@Override
protected void onPause() {
stopBackgroundThread();
super.onPause();
}
private void stopBackgroundThread() {
mBackgroundThread.quitSafely();
try{
mBackgroundThread.join();
mBackgroundThread= null;
mBackgroundHandler = null;
} catch (InterruptedException e) {
e.printStackTrace();
}
}
private void startBackgroundThread() {
mBackgroundThread = new HandlerThread("Camera Background");
mBackgroundThread.start();
mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
}
}
编辑如何创建一个“不可见的”层而不是一个矩形,并使用它来研究图像?