siebenhaarmi76624/MDT5_1_Ueberwachungssystem_G1
3
1
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Changed VideoDetector.java to detect based on changed pixel count instead of average luminosity

Browse Source
This commit is contained in:
Bastian Kohler 2023-05-28 22:20:56 +02:00
parent 9fce3be6a8
commit ba6765b1fb
1 changed files with 75 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

81
app/src/main/java/com/example/ueberwachungssystem/VideoDetection/VideoDetector.java
View File

@ -10,7 +10,6 @@ import androidx.annotation.NonNull;
import androidx.camera.core.CameraSelector;
import androidx.camera.core.ExperimentalGetImage;
import androidx.camera.core.ImageAnalysis;
import androidx.camera.core.ImageProxy;
import androidx.camera.core.Preview;
import androidx.camera.lifecycle.ProcessCameraProvider;
import androidx.camera.view.PreviewView;
@ -37,10 +36,15 @@ public class VideoDetector extends Detector {
private final float DELTA_LUMINOSITY_THRESHOLD = 1.5f;
private Float previousLuminosity = null;
private static final int PIXEL_THRESHOLD = 50; // Luminosity (brightness channel of YUV_420_888)
private static final int ALARM_THRESHOLD = 1; // Percent of pixels changed
private ByteBuffer previousBuffer = null;
/** Constructor */
public VideoDetector(Context context) {
super();
this.context = context;
}
@ -54,9 +58,7 @@ public class VideoDetector extends Detector {
// Request Camera Provider
final ListenableFuture<ProcessCameraProvider> cameraProviderFuture = ProcessCameraProvider.getInstance(context);
//Check for Camera availability
cameraProviderFuture.addListener(new Runnable() {
@Override
public void run() {
cameraProviderFuture.addListener(() -> {
try {
cameraProvider = cameraProviderFuture.get();
bindLuminosityAnalysis(cameraProvider);
@ -64,7 +66,6 @@ public class VideoDetector extends Detector {
} catch (ExecutionException | InterruptedException e) {
// No errors need to be handled for this Future. This should never be reached.
}
}
},ContextCompat.getMainExecutor(context));
}
@ -91,25 +92,34 @@ public class VideoDetector extends Detector {
ImageAnalysis.Builder builder = new ImageAnalysis.Builder();
builder.setTargetResolution(new Size(640, 480));
builder.setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST);
builder.setOutputImageFormat(ImageAnalysis.OUTPUT_IMAGE_FORMAT_YUV_420_888);
ImageAnalysis imageAnalysis = builder.build();
// Set Analyzer
imageAnalysis.setAnalyzer(ContextCompat.getMainExecutor(context), new ImageAnalysis.Analyzer() {
@Override
public void analyze(@NonNull ImageProxy imageProxy) {
imageAnalysis.setAnalyzer(ContextCompat.getMainExecutor(context), imageProxy -> {
if (imageProxy.getFormat() == ImageFormat.YUV_420_888) {
Image image = imageProxy.getImage();
assert image != null;
// Analyze frame
float luminosity = calculateLuminosity(image);
Log.d("Video Detector", String.valueOf(luminosity));
if (previousLuminosity != null)
checkForViolation(luminosity, previousLuminosity);
previousLuminosity = luminosity;
// Luminosity Detection
//float luminosity = calculateLuminosity(image);
//if (previousLuminosity != null)
// checkForViolation(luminosity, previousLuminosity);
//previousLuminosity = luminosity;
// Changed Pixel Detection
int pixelChanged = getChangedPixelCount(image);
int width = image.getWidth();
int height = image.getHeight();
float percentPixelChanged = (float) 100f * pixelChanged / (width * height);
if (percentPixelChanged > ALARM_THRESHOLD)
reportViolation("0", "Video", percentPixelChanged);
}
imageProxy.close();
}
});
// Create Preview
Preview preview = new Preview.Builder().build();
@ -149,11 +159,50 @@ public class VideoDetector extends Detector {
}
/** Calculate Amount of Pixels changed */
private int getChangedPixelCount(Image image) {
int width = image.getWidth();
int height = image.getHeight();
Image.Plane[] planes = image.getPlanes();
ByteBuffer buffer = planes[0].getBuffer();
int yRowStride = image.getPlanes()[0].getRowStride();
int yPixelStride = image.getPlanes()[0].getPixelStride();
int changedPixelCount = 0;
if (previousBuffer == null) {
previousBuffer = ByteBuffer.allocate(buffer.capacity());
buffer.rewind();
previousBuffer.put(buffer);
previousBuffer.rewind();
}
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width; x++) {
int index = (y * yRowStride) + (x * yPixelStride);
int luminosity = (buffer.get(index) & 0xff);
int previousLuminosity = (previousBuffer.get(index) & 0xff);
int diff = Math.abs(luminosity - previousLuminosity);
if (diff > PIXEL_THRESHOLD)
changedPixelCount++;
}
}
// Reset and copy Byte Buffer
buffer.rewind();
previousBuffer.rewind();
previousBuffer.put(buffer);
return changedPixelCount;
}
/** Check if delta Luminosity exceeds threshold */
private void checkForViolation(float luminosity, float previousLuminosity) {
float deltaLuminosity = Math.abs(luminosity - previousLuminosity);
if (deltaLuminosity > DELTA_LUMINOSITY_THRESHOLD) {
reportViolation("1232", "Video",luminosity);
reportViolation("0", "Video",luminosity);
Log.d("Violation", "Violation");
}
Log.d("Delta", String.valueOf(Math.abs(previousLuminosity - luminosity)));